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10,754,389 | ACCEPTED | Chip light emitting diode and fabrication method thereof | A chip light emitting diode having a wide viewing angle, and a fabrication method thereof. The chip light emitting diode has a resin package sealing a light emitting chip which has at least one curved projecting part. The curved projecting part has a cross section which is substantially semicircular, or substantially or partially elliptical or parabolic. The curved projecting part preferably has a cross section which is comprised of a plurality of straight lines, an angle being formed between adjacent lines. The cross section is elongated to form a cylindrical outer surface of the resin package. | 1. A chip light emitting diode comprising: a metal pad and a lead spaced away from each other on a printed circuit board; a light emitting chip mounted on the metal pad; a wire connecting the light emitting chip and the lead; and a resin package sealing the light emitting chip and at least a part of the metal pad, lead, and the wire, the resin package having at least one curved projecting part. 2. A chip light emitting diode as recited in claim 1, wherein the curved projecting part has a cross section which is substantially semicircular, or substantially or partially elliptical or parabolic. 3. A chip light emitting diode as recited in claim 1, wherein the curved projecting part has a cross section which is comprised of a plurality of straight lines with an angle formed between adjacent lines. 4. A chip light emitting diode as recited in claim 1, wherein at least one stepped part is formed at an outer edge of the resin package. 5. A chip light emitting diode as recited in claim 1, wherein the surface of the resin package has fine striations to scattering light emitted from the light emitting chip. 6. A chip light emitting diode as recited in claim 1, wherein the resin package has one projecting part. 7. A chip light emitting diode as recited in claim 1, wherein the resin package has two projecting parts which are spaced away from each other by a predetermined interval, wherein the predetermined interval ranges from 0.1 to 0.4 times a bottom length of the resin package 8. A fabrication method of a chip light emitting diode, comprising the steps of: mounting a light emitting chip on a metal pad formed on a printed circuit board; connecting the light emitting chip to a lead formed on the printed circuit board; providing the printed circuit board within a mold having a cavity, the cavity corresponding to at least one projecting part of the chip light emitting diode; and forming a resin package sealing the light emitting chip and at least a part of the metal pad and lead by injecting resin material into the cavity of the mold, the resin package having at least one curved projecting part. | BACKGROUND OF THE INVENTION (a) Field of the Invention The present invention relates to a chip light emitting diode and a fabrication method thereof. (b) Description of the Related Art Chip light emitting diodes (LEDs) are generally employed as display devices and for backlighting. Recently, their use range has been increased to include various applications such as light sources for mobile phones and personal digital assistants (PDAs). Referring to FIG. 1, a conventional chip LED 50 is provided with a metal pad 52 and a lead 55 on a printed circuit board (PCB) 51. A light emitting chip 53 mounted on the metal pad 52 is connected to the lead 55 via a wire 54. A resin package 56 is formed of an epoxy mold compound (EMC), and seals the chip 53. The conventional chip LED 50 has drawbacks in that optical paths of emitted light rays are limited because the resin package 56 has a rectangular cross section, causing a narrow viewing angle of the chip LED. Further, the intensity distribution of the emitted light is concentrated at the position of the chip. Therefore, many chip LEDs are required to light a certain area, resulting in high manufacturing cost in some applications such as for backlighting. Further, heat generated from the conventional chip LED 50 during operation is concentrated in the edges, resulting in thermal or mechanical deformation of the diode. When the thickness of the resin package is reduced for overall compactness of the conventional chip LED, a metal mold of the resin package should be more precisely formed for the edges, which may result in high manufacturing costs. Further, when the thickness of the resin package happens to be not uniform, stress may be concentrated at a thin part, so the adhesive strength is deteriorated causing poor reliability of the chip LED. SUMMARY OF THE INVENTION In view of the prior art described above, it is an object of the present invention to provide a chip light emitting diode (LED) having a wide viewing angle and a fabrication method thereof. It is another object of the present invention to provide a chip LED in which the light intensity is substantially uniform on either side in order to illuminate a larger area with high brightness. It is another object of the present invention to provide a chip LED in which the heat generated is distributed uniformly to avoid thermal and mechanical deformation and to prevent stress from centralizing on one side. It is still another object of the present invention to provide a fabrication method of a chip LED, in which a simple metal mold structure can be employed to reduce fabrication costs. To achieve these and other objects, as embodied and broadly described herein, a chip light emitting diode includes: a metal pad and a lead spaced away from each other on a printed circuit board; a light emitting chip mounted on the metal pad; a wire connecting the light emitting chip and the lead; and a resin package sealing the light emitting chip and at least a part of the metal pad, the lead, and the wire, the resin package having at least one curved projecting part. The curved projecting part has a cross section which is substantially semicircular, or substantially or partially elliptical or parabolic. The curved projecting part preferably has a cross section which is comprised of a plurality of straight lines, an angle being formed between adjacent lines. According to another aspect of the present invention, a fabrication method of a chip light emitting diode comprises the steps of: mounting a light emitting chip on a metal pad formed on a printed circuit board; connecting the light emitting chip to a lead formed on the printed circuit board; providing the printed circuit board within a mold having a cavity, the cavity corresponding to at least one projecting part of the chip light emitting diode; and forming a resin package sealing the light emitting chip and at least a part of the metal pad and lead by injecting resin material into the cavity of the mold, the resin package having at least one curved projecting part. 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 The accompanying drawings provide a further understanding of the invention and, together with the Detailed Description, explain the principles of the invention. In the drawings: FIG. 1 is a perspective view of a conventional chip light emitting diode; FIG. 2 is a perspective view of a chip light emitting diode according to a first preferred embodiment; FIG. 3 is an enlarged sectional view taken along lines A-A of FIG. 2; FIGS. 4a and 4b shows characteristics of viewing angle according to the chips of FIG. 2 and FIG. 1, respectively; FIGS. 5 to 7 show other examples of the resin package in the chip light emitting diodes according to the first preferred embodiment; FIG. 8 is a perspective view of a chip light emitting diode according to a second preferred embodiment; FIG. 9 is a sectional view along lines A-A of FIG. 8; FIGS. 10 and 11 show other examples of the resin package in the chip light emitting diodes according to the second preferred embodiment; and FIG. 12 shows a flow chart illustrating a fabricating method of a chip light emitting diode according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the accompanying drawings. Referring to FIGS. 2 and 3, a chip light emitting diode (LED) 100 according to a first preferred embodiment of the present invention has a metal pad 120 and a lead 150 provided on a printed circuit board (PCB) 110, and a light emitting chip 130 mounted on the metal pad 120. The metal pad 120 is made of an electrically conductive material, and the chip 130 may be suitably selected from among light emitting chips of wavelengths ranging from infrared to ultraviolet. A wire 140 connects the light emitting chip 130 to the lead 150, and a resin package is formed protruding from the PCB 110 to seal the chip 130 and parts of the lead 150 and metal pad 120. The resin package 160 has a curved projecting part 161 which has a cross section that is substantially semicircular. The cross section is elongated to form a cylindrical outer surface of the resin package 160. A suitable epoxy resin may be injected and molded into the resin package 160 using a metal mold (not shown) with a curved cavity. Light rays R emitted by the chip 130 are refracted on the gently curved surface with different refractive angles. This causes light intensity distribution to become uniform and the viewing angle to be wide. As shown in the enlarged sectional view of FIG. 3, the surface of the resin package 160 may have fine striations to scatter light emitted from the chip 130. The striations may be formed with a triangular shape, a sinusoidal wave shape, or another suitable shape. The period p of the striations preferably ranges from about 0.5 μm to 1.0 μm. The striations may scatter the light emitted by the chip 130 during refraction on the surface of the resin package 160 to further widen the viewing angle. As shown in FIGS. 4A and 4B, in which the viewing angles of the chip LED 100 according to the present invention and the conventional chip LED 50 are respectively shown, the chip LED 100 has a viewing angle ranging about 160° from H(a) to H(b) shown in a bold line, while the conventional chip LED 50 has a viewing angle ranging about 120° from H(a′) to H(b′), under the same experimental conditions. Therefore, it is noted that the viewing angle of the chip LED 100 according to the present invention is enhanced by about 400 with respect to the conventional chip LED 50 The resin package 160 of the chip LED 100 has no sharp edge, but rather it has a gently curved surface without limitation of the light path. This causes the light efficiency to be increased, as confirmed by experimental results shown in TABLE 1 which were obtained by the inventors through many experiments. TABLE 1 shows only average values of the light intensity and brightness according to the chip LED 100 and the conventional chip LED 50. TABLE 1 Average light intensity Average Brightness (mcd) (cd/m2) Chip LED according to the 26 980 first preferred embodiment Conventional chip LED 20 700 The experimental results of TABLE 1 were measured under the condition that the light emitting chips 100, 50 had the same dimensions of 304 μm in width, 304 μm in depth, and 100 μm in height, and input currents of 5 mA in light intensity measurement and 15 mA in brightness measurement. Referring to TABLE 1, the chip LED 100 according to the present invention is enhanced in light intensity by 6 mcd and in brightness by 280 cd/m′ on average with respect to the conventional chip LED 50. Therefore, it is noted that the chip LED 100 has more light efficiency than the conventional one. The curved projecting part 161 of the resin package 160 is described having a cross section of a semicircle referring to FIGS. 2 and 3, but it is not limited thereto. The cross section of the curved projecting part 161 may be variably modified. FIGS. 5 to 7 shows examples of chip LEDs having resin packages of various cross sections. Referring now to FIG. 5, the chip LED 200 has a resin package 260. The resin package 260 has a curved projecting part 261 which has a cross section that is substantially semicircular, similar to that of FIG. 2 or FIG. 3. Further, the cross section of the curved projecting part 261 is comprised of a plurality of straight lines with an angle θ formed between adjacent lines. The angle θ may be the same over the entire curvature, or different depending on location. The cross section is elongated to form a cylindrical outer surface of the resin package 260. The resin package 260 may serve a similar function as the resin package 160 according to the first preferred embodiment. Referring to FIG. 6, a resin package 360 of a chip LED 300 has a stepped part 390 along edges on the elongated sides. The resin package 360 has a curved projecting part 361 to serve a similar function as the resin package 160 according to the first preferred embodiment. Although one stepped part is formed on each side in FIG. 6, it is possible to provide two or more stepped parts on each side as necessary. It is also possible to provide a chip LED 400 with a resin package 460, as shown in FIG. 7, whose upper surface is curved while side surfaces thereof are flat. The present invention is not limited to the above-described embodiments. A curved projecting part of the resin package may have a cross section that is partly elliptical, parabolic, or circular, or any modification thereof. A surface of the resin package may have fine striations to scatter light, resulting in further widening of the range of viewing angle. The resin package according to the present invention may be easily adapted to chip LEDs having a two-top structure. Referring next to FIGS. 8 and 9, a chip LED 600 according to a second preferred embodiment of the present invention will be described. The chip LED 600 is similar to the chip LED 100 according to the first preferred embodiment, except the shape of a resin package 660. The resin package 660 of the chip LED 600 has two curved projecting parts 661, 662. Both curved projecting parts 661, 662 are spaced out by spacer 663 with an interval l therebetween. The interval l may be selected from a range of 0.1 to 0.4 times the bottom length b in the cross section. In the chip LED 600 according to the second preferred embodiment, light rays emitted by the chip 130 are transmitted and refracted on the two curved surface of the projecting parts 661 and 662. Then, the refracted rays diverge to provide a large viewing angle. This may enhance the lighting effect of both sides on a predetermined area. Although the resin package 660 of the chip LED 600 according to the second preferred embodiment is described to have two projecting parts 661, 662, it is also possible to form more than two projecting parts in a resin package. FIGS. 10 and 11 show other examples of the resin package. A chip LED 700 of FIG. 10 has a resin package 760 with two projecting parts 761, 762 which are formed adjacent to each other without any spacer. A chip LED 800 having a resin package 860 is shown in FIG. 11. Three projecting parts 861, 862, 863 are formed with two spacers 864, 865. Light rays emitted by the chip 130 in the chip LED 700 or 800 are transmitted and refracted in the projecting parts 661, and they diverge with a large viewing angle. This may enhance the lighting effect as compared to the conventional chip LED 50 in FIG. 1. It is also possible that the surface of the resin package according to the second preferred embodiment may have fine striations to scatter light, resulting in further widening of the range of viewing angle. Referring next to FIG. 12 with FIG. 2, a fabrication method of a chip LED will be described. First, the metal pad 120 and lead 150 are formed on the PCB 110 (S1). The chip 130 is mounted on the metal pad 120 and then connected to the lead 150 with the wire 140 (S2-S3). The chip 130 may be suitably selected from among light emitting chips of a desired wavelength. The PCB 110 is then mounted on a mold having a cavity (S4). The cavity corresponds to the projecting part(s) according to one of the first preferred embodiment and the second preferred embodiment. Next, a solid epoxy mold compound is heated to 170-1800 and injected into the mold. The resin package 160 is formed on the PCB 110 with the shape described in the first or second preferred embodiment (S5). The resin package is formed to seal the light emitting chip. It is possible that the resin package is formed to seal either a part of the metal pad and lead, or the entire surface of the metal pad and lead. Practically, a plurality of chip LEDs are formed on one PCB, which for example has a size of about 80 mm×50 mm. Therefore, each chip LED on the PCB is individually cut off (S6). As described above, light rays emitted from the light emitting chip diverge radially and uniformly in a chip LED according to the present invention, to further widen the viewing angle. The lighting efficiency of the chip LED is also improved, so the number of chip LEDs is reduced in application to backlighting to light a certain area. Heat generated from the chip LED according to the present invention is also uniformly distributed on the surface, to prevent the chip LED from deforming thermally or mechanically. Further, stress is not concentrated on one side, to enhance the adhesive characteristics between the resin package and the PCB, especially in compact chip LEDs. Since a mold with a curved projecting part is easily manufactured, as compared to a resin package with a rectangular cross section, a relatively simple mold structure for a resin package reduces fabrication costs. It will be apparent to those skilled in the art that various modifications and variations can be made to the device and method of the present invention without departing from the spirit and scope of the invention. The present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. | <SOH> BACKGROUND OF THE INVENTION <EOH>(a) Field of the Invention The present invention relates to a chip light emitting diode and a fabrication method thereof. (b) Description of the Related Art Chip light emitting diodes (LEDs) are generally employed as display devices and for backlighting. Recently, their use range has been increased to include various applications such as light sources for mobile phones and personal digital assistants (PDAs). Referring to FIG. 1 , a conventional chip LED 50 is provided with a metal pad 52 and a lead 55 on a printed circuit board (PCB) 51 . A light emitting chip 53 mounted on the metal pad 52 is connected to the lead 55 via a wire 54 . A resin package 56 is formed of an epoxy mold compound (EMC), and seals the chip 53 . The conventional chip LED 50 has drawbacks in that optical paths of emitted light rays are limited because the resin package 56 has a rectangular cross section, causing a narrow viewing angle of the chip LED. Further, the intensity distribution of the emitted light is concentrated at the position of the chip. Therefore, many chip LEDs are required to light a certain area, resulting in high manufacturing cost in some applications such as for backlighting. Further, heat generated from the conventional chip LED 50 during operation is concentrated in the edges, resulting in thermal or mechanical deformation of the diode. When the thickness of the resin package is reduced for overall compactness of the conventional chip LED, a metal mold of the resin package should be more precisely formed for the edges, which may result in high manufacturing costs. Further, when the thickness of the resin package happens to be not uniform, stress may be concentrated at a thin part, so the adhesive strength is deteriorated causing poor reliability of the chip LED. | <SOH> SUMMARY OF THE INVENTION <EOH>In view of the prior art described above, it is an object of the present invention to provide a chip light emitting diode (LED) having a wide viewing angle and a fabrication method thereof. It is another object of the present invention to provide a chip LED in which the light intensity is substantially uniform on either side in order to illuminate a larger area with high brightness. It is another object of the present invention to provide a chip LED in which the heat generated is distributed uniformly to avoid thermal and mechanical deformation and to prevent stress from centralizing on one side. It is still another object of the present invention to provide a fabrication method of a chip LED, in which a simple metal mold structure can be employed to reduce fabrication costs. To achieve these and other objects, as embodied and broadly described herein, a chip light emitting diode includes: a metal pad and a lead spaced away from each other on a printed circuit board; a light emitting chip mounted on the metal pad; a wire connecting the light emitting chip and the lead; and a resin package sealing the light emitting chip and at least a part of the metal pad, the lead, and the wire, the resin package having at least one curved projecting part. The curved projecting part has a cross section which is substantially semicircular, or substantially or partially elliptical or parabolic. The curved projecting part preferably has a cross section which is comprised of a plurality of straight lines, an angle being formed between adjacent lines. According to another aspect of the present invention, a fabrication method of a chip light emitting diode comprises the steps of: mounting a light emitting chip on a metal pad formed on a printed circuit board; connecting the light emitting chip to a lead formed on the printed circuit board; providing the printed circuit board within a mold having a cavity, the cavity corresponding to at least one projecting part of the chip light emitting diode; and forming a resin package sealing the light emitting chip and at least a part of the metal pad and lead by injecting resin material into the cavity of the mold, the resin package having at least one curved projecting part. Both the foregoing general description and the following Detailed Description are exemplary and are intended to provide further explanation of the invention as claimed. | 20040109 | 20060509 | 20050127 | 72292.0 | 0 | HA, NATHAN W | CHIP LIGHT EMITTING DIODE AND FABRICATION METHOD THEREOF | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,754,397 | ACCEPTED | Load leveling yarns and webbings | An improved load leveling yarn has a force-displacement profile that maintains desirable properties of previously known yarns (as exemplified in U.S. Pat. No. 5,830,811), but exhibits a lower elongation at a stress that is greater than the IBS but less than or equal to 1.8 grams/denier. Especially preferred yarns are produced from PET with an IV of greater than 0.9 and epsilon caprolactone (at a ratio of about 90:10) under copolymerization conditions that allow reaction of at least 95% of the added epsilon caprolactone. Such yarns can then be formed into a web to form specific products, and especially seat belts. | 1. A yarn having a force-displacement profile such that: (a) when said yarn is subjected to an initial barrier stress of from about 0.2 gram/denier to less than or equal to about 1.4 grams/denier, said yarn elongates to less than 3 percent and the initial modulus ranges from about 20 grams/denier to about 150 grams/denier; (b) upon subjecting said yarn to greater than said initial barrier stress and less than or equal to 1.8 denier, said yarn elongates further to an amount of no more than about 10 percent at less than or equal to 1.8 grams/denier and the energy absorbed from 0 to the elongation at 1.8 grams/denier is at least about 0.0008 Joule/denier*meter; and (c) upon subjecting said yarn to greater than 1.8 grams/denier, the modulus increases sharply and said yarn elongates further until said yarn breaks at a tensile strength of at least about 5 grams/denier and a total elongation of less than 25 percent, wherein said yarn comprises a multiplicity of fibers, all of said fibers have substantially the same force-displacement profile, are made from polymers having a glass transition temperature in the range from about −10° C. to about +60° C., and are not de from polybutylene terephthalate homopolymer. 2. The yarn of claim 1 wherein said yarn in part (a) elongates to less than about 2 percent, and in part (b) elongates to less than about 7 percent. 3. The yarn of claim 1 wherein said yarn is made from homopolymers, random copolymers, diblock copolymers, triblock copolymers, or segmented block copolymers. 4. The yarn of claim 3 wherein said yarn is made from a homopolymer selected from the group consisting of polytriethylene terephthalate; polyisobutylene terephthalate; and long chain alkylene terephthalate and naphthalate polymers. 5. The yarn of claim 3 wherein said yarn is made from a diblock copolymer. 6. The yarn of claim 1 wherein said yarn is made from a diblock copolymer, triblock copolymer, or segmented block copolymer comprising (a) at least one first block of polyester wherein said first block is made from an aromatic polyester and (b) at least one second block of polyester wherein said second block is made from lactone monomer. 7. The yarn of claim 5 wherein said diblock copolymer comprises: (a) a first block of polyester wherein said first block is made from an aromatic polyester and (b) a second block of polyester wherein said second block is made from lactone monomer. 8. The yarn of claim 6 wherein said aromatic polyester is selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polyalkylene naphthalates, polycycloalkylene naphthalates, polybutylene terephthalate, and polytrimethylene terephthalate. 9. The yarn of claim 7 wherein said aromatic polyester is selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polyalkylene naphthalates, polycycloalkylene naphthalates, polybutylene terephthalate, and polytrimethylene terephthalate. 10. The yarn of claim 6 wherein said aromatic polyester is polyethylene terephthalate. 11. The yarn of claim 7 wherein said aromatic polyester is polyethylene terephthalate. 12. The yarn of claim 6 wherein said lactone monomer is selected from the group consisting of epsilon-caprolactone, propiolactone, butyrolactone, and valerolactone. 13. The yarn of claim 7 wherein said lactone monomer is selected from the group consisting of epsilon-caprolactone, propiolactone, butyrolactone, and valerolactone. 14. The yarn of claim 12 wherein the amount of said lactone monomer is from about 5 to about 45 weight percent so as to achieve the desired initial barrier stress and impact energy absorption with load leveling performance. 15. The yarn of claim 13 wherein the amount of said lactone monomer is from about 10 to about 45 weight percent so as to achieve the desired initial barrier stress and impact energy absorption with load leveling performance. 16. A web comprising a warp yarn, said yarn having a force-displacement profile such that: (a) when said yarn is subjected to an initial barrier stress of from about 0.2 gram/denier to less than or equal to about 1.4 grams/denier, said yarn elongates to less than 3 percent and the initial modulus ranges from about 20 grams/denier To about 150 grams/denier; (b) upon subjecting said yarn to greater than said initial barrier stress and less than or equal to 1.8 grams/denier, said yarn elongates further to an amount of no more than about 10 percent at less than or equal to 1.8 grams/denier, and the energy absorbed from 0 to the elongation at 1.8 grams/denier is at least about 0.0008 Joule/denier*meter; and (c) upon subjecting said yarn to greater than 1.8 grams/denier, the modulus increases sharply and said yarn elongates further until said yarn breaks at a tensile strength of at least about 5 grams/denier and a total elongation of less than 25 percent, wherein said yarn comprises a multiplicity of fibers, all of said warp yarns having substantially the same force-displacement profile, are made from polymer having a glass transition temperature in the range from about −10° C. to about +60° C., and are not made from polybutylene terephthalate homopolymer. 17. The web of claim 16 wherein said yarn in part (a) elongates to less than about 2 percent, and in part (b) elongates to less than about 7 percent. 18. The web of claim 16 wherein said yarn is made from homopolymers, random copolymers, diblock copolymers, triblock copolymers, or segmented block copolymers. 19. The web of claim 18 wherein said yarn is made from homopolymer selected from the group consisting of polytrimethylene terephthalate; polyisobutylene terephthalate; and long chain alkylene terephthalate and naphthalate polymers. 20. The web of claim 18 wherein said yarn is made from a diblock copolymer. 21. The web of claim 16 wherein said yarn is made from a diblock copolymer, triblock copolymer, or segmented block copolymer comprising: (a) at least one first block of polyester wherein said first block is made from an aromatic polyester and (b) at least one second block of polyester wherein said second block is made from lactone monomer. 22. The web of claim 20 wherein said diblock copolymer comprises: (a) a first block of polyester wherein said first block is made from an aromatic polyester and (b) a second block of polyester wherein said second block is made from lactone monomer. 23. The web of claim 21 wherein said aromatic polyester is selected from the group consisting of polyethylene terephthalate; polyethylene naphthalate; polyalkylene naphthalates; polycycloalkylene naphthalates; polybutylene terephthalate; and polytrimethylene terephthalate. 24. The web of claim 22 wherein said aromatic polyester is selected from the group consisting of polyethylene terephthalate; polyethylene naphthalate; polyalkylene naphthalates; polycycloalkylene naphthalates; polybutylene terephthalate; and polytrimethylene terephthalate. 25. The web of claim 21 wherein said aromatic polyester is polyethylene terephthalate. 26. The web of claim 22 wherein said aromatic polyester is polyethylene terephthalate. 27. The web of claim 21 wherein said lactone monomer is selected from the group consisting of epsilon-caprolactone, propiolactone, butyrolactone, and valerolactone. 28. The web of claim 22 wherein said lactone monomer is selected from the group consisting of epsilon-caprolactone, propiolactone, butyrolactone, and valerolactone. 29. The web of claim 27 wherein the amount of said lactone monomer is from about 5 to about 45 weight percent so as to achieve the desired initial barrier stress and impact energy absorption with load leveling performance. 30. The web of claim 28 wherein the amount of said lactone monomer is from about 5 to about 45 weight percent so as to achieve the desired initial barrier stress and impact energy absorption with load leveling performance. 31. A seat belt made from said web of claim 16. 32. A method of restraining a vehicle occupant in a vehicle collision comprising the step of: using an impact energy absorption and load leveling web which restrains said vehicle occupant with force from about 450 pounds (about 2,000 Newtons) to about 1,800 pounds (about 8,000 Newtons) and comprises warp yarn, said yarn having a force-displacement profile such that: (a) when said yarn is subjected to an initial barrier stress of from about 0.2 gram/denier to less than or equal to about 1-4 grams/denier, said yarn elongates to less than 3 percent and the initial modulus ranges from about 20 grams/denier to about 150 grams/denier; (b) upon subjecting said yarn to greater than said initial barrier stress and less than or equal to 1.8 gams/denier, said yarn elongates further to an amount of no more than about 10 percent at less Than or equal to 1.8 grams/denier, and the energy absorbed from 0 to the elongation at 1.8 grams/denier is at least about 0.0008 Joule/denier*meter; and (c) upon subjecting said yarn to greater than 1.8 grams/denier, the modulus increases sharply and said yarn elongates further until said yarn breaks at a tensile strength of at least about 5 grams/denier and a total elongation of less than 25 percent, wherein said yarn comprises a multiplicity of fibers, all of said warp yarns have substantially the same force-displacement profile, are made from polymers having a glass transition temperature in the range from about −10° C. to about +60° C., and are not made from polybutylene terephthalate homopolymer. 33. The method of claim 32 wherein said yarn in part (a) elongates to less than about 2 percent, and in part (b) elongates to less than about 7 percent. 34. The method of claim 32 wherein said yarn is made from homopolymers, random copolymers, diblock copolymers, triblock copolymers, or segmented block copolymers. 35. The method of claim 34 wherein said yarn is made from homopolymer selected from the group consisting of polytrimethylene terephthalate; polyisobutylene terephthalate; and long chain alkylene terephthalate and naphthalate polymers. 36. The method of claim 34 wherein said yarn is made from a diblock copolymer. 37. The method of claim 32 wherein said yarn is made from a diblock copolymer, triblock copolymer, or segmented block copolymer comprising: (a) at least one fist block of polyester wherein said first block is made from an aromatic polyester and (b) at least one second block of polyester wherein said second block is made from lactone monomer. 38. The method of claim 36 wherein said diblock copolymer comprises: (a) a first block of polyester wherein said first block is made from an aromatic polyester and (b) a second block of polyester wherein said second block is made from lactone monomer. 39. The method of claim 37 wherein said aromatic polyester is selected from the group consisting of polyethylene terephthalate; polyethylene naphthalate; polyalkylene naphthalates; polycycloalkylene naphthalates; polybutylene terephthalate; and polytriethylene terephthalate. 40. The method of claim 38 wherein said aromatic polyester is selected from the group consisting of polyethylene terephthalate; polyethylene naphthalate; polyalkylene naphthalates; polycycloalkylene naphthalates; polybutylene terephthalate; and polytrimethylene terephthalate. 41. The method of claim 37 wherein said aromatic polyester is polyethylene terephthalate. 42. The method of claim 38 wherein said aromatic polyester is polyethylene terephthalate. 43. The method of claim 37 wherein said lactone monomer is selected from the group consisting of epsilon-caprolactone, propiolactone, butyrolactone, and valerolactone. 44. The method of claim 38 wherein said lactone monomer is selected from the group consisting of epsilon-caprolactone, propiolactone, butyrolactone, and valerolactone. 45. The method of claim 43 wherein the amount of said lactone monomer is from about 5 to about 45 weight percent so as to achieve the desired initial barrier stress and load leveling performance. 46. The method of claim 44 wherein the amount of said lactone monomer is from about 5 to about 45 weight percent so as to achieve the desired initial barrier stress and load leveling performance. | FIELD OF THE INVENTION Compositions and methods for load leveling yarns and products produced therefrom. BACKGROUND OF THE INVENTION A typical vehicle safety seat belt system is intended to restrict the displacement of an occupant with respect to the occupant's seated position within the vehicle when the vehicle experiences a sudden, sharp deceleration (see e.g., commonly assigned U.S. Pat. No. 3,322,163. Most seat belt systems have three main portions: A retractor belt portion, a torso belt portion, and a lap belt portion, and the performance of each belt portion may be characterized by its force-displacement curve. The area under the force-displacement curve is referred to as the energy absorbed by the safety restraint. Current vehicle safety seat belts are made from fully drawn polyethylene terephthalate (“PET”) fiber which is partially relaxed (2.7%) and having a tenacity of at least 7.5 g/denier and is 14% elongation at break. However, various problems exists with current PET fiber seat belts. Among other things, crash studies indicate that after the initial vehicle impact occurs (e.g., speed of about 35 miles/hr), the occupant tends to move forward from his seated position until the belt engages to build restraining forces. As indicated in Prior Art FIG. 1, the relatively unyielding belt made from PET fiber exerts a load of at least 2000 pounds (about 9000 Newtons) against the occupant so as to cause the occupant to have chest and rib cage injuries at the seat belt torso position and also neck and back injuries when the occupant rebounds and impacts the back structure of the seat assembly. U.S. Government regulation requires that seat belts must withstand loads up to 6,000 lbs. When a car collides at a speed of 35 miles/hour, an impact energy to which an average sized person in the car is subjected is at least 500 Joules on the torso belt. Although the current PET fiber may absorb the impact energy, damage to the vehicle occupant still occurs due to the undesirable force-displacement curve. In 70 milliseconds, an average sized passenger will experience high forces of up to 2,000 pounds (about 9,000 Newtons) as shown in FIG. 1. In order to absorb the impact energy and to reduce the seat belt load against the vehicle occupant, U.S. Pat. No. 3,550,957 discloses a shoulder harness having stitched doubled sections of the webbing arranged above the shoulder of the occupant so that the stitching permits the webbing to elongate from an initial length toward a final length at a controlled rate under the influence of a predetermined restraining force. However, the stitched sections do not give the desirable amount of energy absorption, do not provide uniform response, and are not reusable. See also U.S. Pat. No. 4,138,157. U.S. Pat. No. 3,530,904 discloses a woven fabric which is constructed by weaving two kinds of yarns having relatively different physical properties and demonstrates energy absorption capability. U.S. Pat. Nos. 3,296,062; 3,464,459; 3,756,288; 3,823,748; 3,872,895; 3,926,227; 4,228,829; 5,376,440; and Japanese Patent 4-257336 further disclose webbings which are constructed of multiple kinds of warp yarns having different tenacity and elongations at break. The webbing shows multiple step gives and impact absorbent characteristics. Those skilled in this technical area have recognized the deficiencies in using at least two different yarn types as taught by the preceding references. U.S. Pat. No. 4,710,423 and Kokai Patent Publication 298209 published Dec. 1, 1989 (“Publication 298209”) teach that when using at least two different yarn types, energy absorption occurs in a stepwise manner and thus, the web does not absorb the energy continuously and smoothly. Therefore, after one type of warps absorbs a portion of the impact energy, and before another type of warps absorbs another portion of the impact energy, the human body is exposed to an undesirable shock. In addition, these types of seat belts are not reusable. U.S. Pat. No. 3,486,791 discloses energy absorbing devices such as a rolled up device which separates a slack section of the belt from the taut body restraining section by clamping means which yield under a predetermined restraining force to gradually feed out the slack section so that the taut section elongates permitting the restrained body to move at a controlled velocity. The reference also describes a device which anchors the belt to the vehicle by an anchor member attached to the belt and embedded in a solid plastic energy absorber. These kinds of mechanical devices are expensive, are not reusable, provide poor energy absorption, and are difficult to control. An improvement on the foregoing devices is taught by commonly assigned U.S. Pat. No. 5,547,143 which describes a load absorbing retractor comprising: a rotating spool or reel, seat belt webbing secured to the reel; and at least one movable bushing, responsive to loads generated during a collision situation, for deforming a portion of the reel and in so doing dissipating a determined amount of the energy. U.S. Pat. No. 4,710,423 and Publication 298209 disclose webbing comprised of PET yarns having tenacity of at least 4 grams/denier and an ultimate elongation of from 50% to 80%. Due to the inherent physical properties of PET yarn, the Examples show that, at 5% elongation, the load has already reached more than 700 kg (about 1500 lbs). The damage to the occupant by seat belt still exists and thus, the belt needs to be further modified. Examples in these two patents also show that if PET yarn is overrelaxed, the tenacity drops to 2.3 g/denier. Kokai Patent Publication 90717 published Apr. 4, 1995 discloses high strength polybutylene terephthalate homopolymer (“PBT”) fiber based energy absorption webbing. The fiber's tenacity is over 5.8 g/denier, breaking elongation is over 18.0%, and the stress at 10% elongation is less than 3.0 g/d. However, this reference fails to teach PBT fiber demonstrating the initial stress requirement which engages the seat belt to protect the occupant and the means to control the initial stress barrier. Consequently, it would be desirable to have an improved energy absorbing seat belt which has a smoother performance than that of the known stitched webbing approach or the known use of at least two different fibers, is reusable unlike the known clamp approach, and also addresses the ability to control the initial barrier stress and the impact energy absorption. U.S. Pat. Nos. 5,830,811; 5,869,582; 6,071,835, 6,057,252 and 6,228,488 describe load leveling yarns, the copolymers from which they are made, the process by which they are made and the webbing in which they are utilized, which satisfy the requirement for a smooth energy absorbing seat belt. Subsequent seat belt development work has elucidated the need for an energy absorbing seat belt which effectively absorbs the initial shock of a rapid deceleration, but with less total elongation as is described by the load leveling yarns of U.S. Pat. No. 5,830,811 and its seat belts. For example, in rapid deceleration situations, occupants of the 95 weight percentile, could in belts more than is acceptable for use in rear seats. It would therefore be desirable to have an improved seat belt with the energy absorbing performance of the load leveling yarns of U.S. Pat. No. 5,830,811, but with lower total elongation at the higher force loads produced by the heaviest occupants. Among other advantages, lower total elongation at higher force loads would prevent excessive excursion of heavier occupants into the back side of the front seats in a rapid deceleration situation. Thus, while numerous compositions and methods for load leveling yarns and webbings are known in the art, all or almost all of them suffer from various disadvantages. Consequently, there is still a need to provide improved load leveling yarns and webbings. SUMMARY OF THE INVENTION The present invention is directed to yarns with improved force displacement profiles, and to various products formed from such yarns. Especially contemplated products include webs made from, or comprising the yarn, and seat belts comprising contemplated yarns. In one preferred aspect of the inventive subject matter, contemplated yarns have a force displacement profile such that (a) when said yarn is subjected to an initial barrier stress of from about 0.2 gram/denier to less than or equal to about 1.4 grams/denier, said yarn elongates to less than 3 percent and the initial modulus ranges from about 20 grams/denier to about 150 grams/denier, (b) when that yarn is subjected to greater than said initial barrier stress and less than or equal to 1.8 grams/denier, the yarn elongates further to at least about 6 percent and the energy absorbed from 0 to the elongation at 1.8 grams/denier is at least about 0.0008 Joule/denier*meter, and (c) upon subjecting the yarn to greater than 1.8 grams/denier, the modulus increases sharply and the yarn elongates further until the yarn breaks at a tensile strength of at least about 5 grams/denier, wherein said yarn comprises a multiplicity of fibers, all of said fibers have substantially the same force-displacement profile, are made from polymers having a glass transition temperature in the range from about −10° C. to about +60° C., and are not made from polybutylene terephthalate homopolymer. In further preferred aspects, the yarn may be fabricated from homopolymers (e.g., polytrimethylene terephthalate, polyisobutylene terephthalate, long chain alkylene terephthalate, or naphthalate polymers), or random copolymers, diblock copolymers, triblock copolymers, or segmented block copolymers, which will preferably include an aromatic polyester segment (e.g., PET, PEN, etc.) and a lactone monomer (e.g., epsilon-caprolactone, propiolactone, butyrolactone, or valerolactone). The lactone monomer is preferably present from about 5 to about 45 weight percent, and even more preferably from about 8 to about 15 weight percent. Various objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS Prior Art FIG. 1 depicts the performance of a known PET seat belt at the torso position. Prior Art FIG. 2A illustrates the force-displacement profile of a yarn and webbing that is manufactured according to a known process (U.S. Pat. No. 5,830,811). FIG. 2B illustrates the force-displacement profile of a yarn and webbing that is manufactured using a process according to the inventive subject matter. DETAILED DESCRIPTION The inventors discovered processes and uses for load leveling yarns that solve at least some of the problems, and particularly excessive elongation under stress above initial barrier stress associated with heretofore known yarns. Webbings comprising such yarns, if used in seat belts, demonstrate different load leveling behavior from about 450 pounds (about 2,000 Newton) to about 1,800 pounds (about 8,000 Newton) in a vehicle collision. In order to meet these requirements, the web comprises warp yarn and the warp yarn has a force-displacement profile characterized by: (a) when the yarn is subjected to an initial barrier stress of from about 0.2 gram/denier to less than or equal to about 1.4 grams/denier, the yarn elongates to less than 3 percent and the initial modulus ranges from about 20 grams/denier to about 150 grams/denier; (b) upon subjecting the yarn to greater than the initial barrier stress and less than or equal to 1.8 grams/denier, the yarn elongates further to at least about 6 percent and the energy absorbed from 0 to the elongation at 1.8 grams/denier is at least 0.0008 Joule/denier-meter; and (c) upon subjecting the yarn to greater than 1.8 grams/denier, the modulus increases sharply and the yarn elongates further until the yarn breaks at a tensile strength of at least about 5 grams/denier, wherein the yarn comprises a multiplicity of fibers, all of said warp yarns having substantially the same force-displacement profile, are made from polymers having a glass transition temperature in the range from about −40° C. to about +70° C., and are not made from polybutylene terephthalate homopolymer. The term “modulus” as used herein-means the slope of the force-displacement curve. It should be especially recognized that webs according to the inventive subject matter are particularly advantageous because of their improved impact energy absorption and smoother performance than that of the known stitched webbing approach or the known use of at least two different fibers. Furthermore, it should be appreciated that webs using contemplated yarns typically provide the ability to control the initial barrier stress and the impact energy absorption. In addition, the total elongation at higher stresses (between IBS and greater than 1.8 gm/denier) is limited at about 6 percent. A particularly preferred yarn has the following force-displacement profile: (a) When the yarn is subjected to an initial barrier stress of from about 0.2 gram/denier to less than or equal to about 1.4 grams/denier, the yarn elongates to less than 3 percent. The initial modulus ranges from about 20 grams/denier to about 150 grams/denier and the preferred initial modulus ranges from about 50 grams/denier to about 150 grams/denier. The initial high modulus is needed to engage the seat belt and the height of the initial barrier stress ensures that all the occupant collision energy will be absorbed under the subsequent load leveling portion of the force-displacement curve. (b) Upon subjecting the yarn to greater than the initial barrier stress and less than or equal to 1.8 grams/denier, the yarn elongates further to at least about 6 percent. Preferably, the yarn elongates from about 3 percent to at least about 20 percent and the energy absorbed from 0 to the elongation at 1.8 grams/denier is at least 0.0008 Joule/denier*meter. This portion of the force-displacement curve is the fiber load leveling portion which prevents the passenger from experiencing excessive loads. (c) Upon subjecting the yarn to greater than 1.8 grams/denier, the modulus increases sharply and the yarn elongates further until the yarn breaks at a tensile strength of at least about 5 grams/denier. In a seat belt assembly comprising the foregoing yarn, the load on the passenger's torso position may be reduced to as low as 450 lbs (about 2,000 Newton) even at a collision speed of 35 miles/hour. The reduced force then minimizes or eliminates potential damage to the passenger. Such yarn is preferably made from a polymer having a glass transition temperature in the range from about −40° C. to about +70° C., more preferably about −20° to about +60° C., and most preferably about −11° C. to about +60° C. It should be recognized that the glass transition temperature will at least in part depend on the particular polymer composition, and it is therefore contemplated that all compositions with the contemplated Tg ranges are considered suitable for use herein. However, it is especially preferred that the polymer has a Tg of between about +50° C. and +60° C. (e.g., about +56° C.) and comprises a homopolymer, random copolymer, diblock copolymer, triblock copolymer, or segmented block copolymer. Examples of particularly preferred homopolymers include polytrimethylene terephthalate, polyisobutylene terephthalate, long chain alkylene terephthalates, and naphthalate polymers. Examples of preferred random copolyesters include copolyesters which, in addition to the ethylene terephthalate unit, contain components such as ethylene adipate, ethylene sebacate, or other long chain alkylene terephthalate units. Such components are preferably present in an amount of 10 percent, or more. Most preferably, the copolyester is formed with an aliphatic polyester (e.g., epsilon caprolactone at an amount of between about 8-15%, and most preferably about 10%). Examples of preferred block copolymers include diblock, triblock, and segmented block structure. Block copolymers comprise at least one hard crystalline aromatic polyester block and at least one soft amorphous aliphatic polyester block. The crystalline aromatic polyester includes the homopolymers such as polyethylene terephthalate; polytrimethylene terephthalate; polybutylene terephthalate; polyisobutylene terephthalate; poly(2,2-dimethylpropylene terephthalate); poly[bis-(hydroxymethyl)cyclohexene terephthalate]; polyethylene naphthalate; polybutylene naphthalate; poly[bis-(hydroxymethyl)cyclohexene naphthalate]; other polyalkylene or polycycloalkylene naphthalates and the mixed polyesters which, in addition to the ethylene terephthalate unit, contain component such as ethylene isophthalate; ethylene adipate; ethylene sebacate; 1,4-cyclohexylene dimethylene terephthalate; or other long chain alkylene terephthalate units. A mixture of aromatic polyesters may also be used. The more preferred aromatic polyesters include PET and PEN. As for amorphous aliphatic polyester block, it is made from lactone monomer. epsilon-caprolactone is the most preferable. In addition, propiolactone, butyrolactone, valerolactone, higher cyclic lactones, and two or more types of lactones may also be used. When PBT is used, the amorphous aliphatic polyester block is present in an amount greater than 10 percent. With respect to diblock polyester copolymers and processes for making same, commonly owned U.S. Pat. No. 5,869,582 (which is a CIP of application Ser. No. 08/788,895 filed Jan. 22, 1997) is incorporated herein by reference. Examples of preferred diblock copolymers include those comprising (a) a first block of polyester wherein the first block is made from aromatic polyester and (b) a second block of polyester wherein the second block is made from lactone monomer. More preferably, the aromatic polyester has: (i) an intrinsic viscosity which is measured in a 60/40 by weight mixture of phenol and tetrachloroethane and is at least about 0.6 deciliter/g and (ii) a Newtonian melt viscosity of at least about 7,000 poises at 280° C. Examples of preferred aromatic polyesters include polyethylene terephthalate (“PET”), polyethylene naphthalate (“PEN”); polybutylene terephthalate (“PBT”); polybutylene naphthalate; poly[bis-(hydroxymethyl)cyclohexene terephthalate]; poly[bis-(hydroxymethyl)cyclohexene naphthalate]; polytrimethylene terephthalate; polyisobutylene terephthalate; poly(2,2-dimethylpropylene terephthalate); other polyalkylene or polycycloalkylene naphthalates and the mixed polyesters which in addition to the ethylene terephthalate unit, contain components such as ethylene isophthalate, ethylene adipate, ethylene sebacate, 1,4-cyclohexylene dimethylene terephthalate, or other alkylene terephthalate units. A mixture of aromatic polyesters may also be used. Commercially available aromatic polyesters may be used. The more preferred aromatic polyesters include PET and PEN. The intrinsic viscosities (“IV”), as measured in a 60/40 by weight mixture of phenol and tetrachloroethane, of the preferred aromatic polyesters are about 0.8 for PET and about 0.6 for PEN. However, more preferred IV for PET is 0.97 and for PEN is 0.8. Preferred lactones include epsilon-caprolactone, propiolactone, butyrolactone, valerolactone, and higher cyclic lactones. Two or more types of lactones may be used simultaneously. For use in load leveling seat belts, the PET-polycaprolactone diblock copolymer may have a polycaprolactone concentration of preferably about 5 to about 45 weight percent, and more preferably about 8 to about 15 weight percent. In the diblock copolymer, the polycaprolactone concentration may be varied to achieve the desired initial barrier stress and impact energy absorption with load leveling performance. Catalysts used in the polymerization of lactones may be used in the diblock copolymerization. Preferred catalysts are organometallics based on metals such as lithium, sodium, potassium, rubidium, cesium, magnesium, inorganic acid salts, oxides organic acid salts and alkoxides of calcium, barium, strontium, zinc, aluminum, titanium, cobalt, germanium, tin, lead, antimony, arsenic, cerium, boron cadmium and manganese; and their organometallic complexes. More preferred catalysts are organic acid salts and organometallic compounds of tin, aluminum and titanium. The most preferred catalysts are tin diacylate, tin tetra acylate, dibutyltin oxide, dibutyltin dilaurate, tin octanoate, tin tetra acetate, triisobutyl aluminum, tetra butyl titanium, germanium dioxide, antimony trioxide, porphyrin and phthalocyanine complexes of these metals. Two or more catalyst types may be used in parallel. Useful catalysts are commercially available. Preferably, the amount of catalyst used is about 0.002 to about 0.2 weight percent based on the combined weight of the aromatic polyester and lactone monomer. In a preferred manner of manufacture, the aromatic polyester is added to an extruder. The aromatic polyester may be added to the extruder in a melt phase as from a melt polymerization reactor, or the aromatic polyester may be added to the extruder in a chip form and then melted in the extruder. Unexpectedly, the inventors discovered that mixing and reaction of the polymeric melt with material having a drastic viscosity difference become feasible to produce the yarns according to the inventive subject matter when the extruder is a twin screw extruder. Suitable twin screw extruders can be either intermeshing counter-rotating or intermeshing co-rotating, both of which provide good dispersive mixing, tight residence time distribution, and effective devolatilization. The screw profile is preferably configured to allow polyester feeding (either in a pellet form or molten form), polyester melting (if pellets are feed), lactone monomer injection, mixing, reaction, devolatilization, and finally pelletization or spinning. The inventors further recognized that the most efficient dispersive and distributive mixing occurs at the position where the lactone monomer is injected into the polyester melt. The initial extrusion temperature exceeds the melting point (as measured by Perkin-Elmer Differential Scanning Calorimeter (DSC) from the maxima of the endotherm resulting from scanning a 2 mg. sample at 20° C. per minute) of the aromatic polyester used. The melting points of the preferred aromatic polyesters are 250° C. for PET and 266° C. for PEN. The preferred initial extrusion zone temperature is at least about 30° C. above the aromatic polyester melting point. Thus, the preferred initial extrusion temperature for PET is at least about 280° C. while the preferred initial extrusion temperature for PEN is at least about 296° C. In cases where the aromatic polyester is fed to the twin screw extruder in a molten form, it is generally preferred that the initial extrusion zone temperature is approximately 10° C. above the aromatic polyester melting point. To promote the diblock copolymer formation and minimize transesterification occurrence, the residence time and extrusion temperature profile are important. After the aromatic polyester is melted, the melt temperature is decreased preferably by at least about 20° C. and more preferably by at least about 50° C. due to the mixing with the injected lactone monomer and catalyst. Preferably, the catalyst is added to the epsilon-caprolactone monomer at room temperature and the epsilon-caprolactone monomer/catalyst mixture is injected into the melted aromatic polyester. Thus, the reactive extrusion temperature for PET is preferably about 260° C. and more preferably about 200 C to about 240° C. while the reactive extrusion temperature for PEN is preferably about 276° C. and more preferably about 246 to about 276° C. The term “residence time” in the extruder as used herein means the extruder volume divided by the output rate. The aromatic polyester and lactone are extruded at a residence time of less than about 30 minutes and at a temperature sufficient to form the diblock copolymer. The preferred residence time is less than about 15 minutes. The more preferred residence time is less than about 10 minutes and the most preferred residence time is less than about 5 minutes. This short residence time minimizes transesterification while ensuring complete polymerization which means to graft the epsilon-caprolactone monomer to form the block at the PET chain end and complete consumption of the injected epsilon-caprolactone monomer. Turbulators are used to increase extruder volume without sacrificing the throughput rate and to control the residence reaction time. To determine residence distribution, we added colored pellets which served as a marker to the polyester pellets. The term “distribution time” means the range starting from the color appearance and ending at color disappearance. As those skilled in the art know, as the distribution time decreases, product uniformity increases. Thus, the preferred distribution time is less than about 4 minutes. The distribution time is more preferably less than about 2 minutes and most preferably less than about 1 minutes. The fiber formation may be achieved by spinning either directly from twin screw extruder or separately from single screw extruder. Both processes consist of extrusion, spinning, drawing and relaxing stages. In the twin screw extruder, reaction and compounding may be conducted in polymer melt with a proper screw profile and process conditions. In the single screw extruder, the polymer pellets may be fed and melted with proper screw design and process conditions. A homogeneous melt is then fed into a spin pot which contains a screen pack and a spinneret. The extruded filaments go through a heated sleeve, are quenched in a cross-flow quench system using conditioned air at a predetermined rate, and taken up by godet at a certain speed. The as-spun yarn is then drawn to its optimum draw ratio to obtain the maximum strength. The relaxation stage shrinks the yarn and produces a yarn with the desired stress-strain curve. Fiber relaxation affects the maximum load which the passenger will experience in the vehicle collision. For example, using a PET/25% Polycaprolactone diblock copolymer, the load experienced by the passenger may change from about 1,500 pounds to about 900 pounds when the fully drawn fiber is relaxed from 5% to 15%. Depending upon the intended use of the present web, additives such as UV stabilizers may be used in or on the fiber. The term “multiplicity of fibers” as used herein means at least two ends of yarn and preferably, at least about 342 ends for seat belts. Seat belts are usually woven with a warp yarn of about 1000 to about 1500 denier and a breaking strength of at least about 5 grams/denier and weft yarn with a denier of about 500 to 900 and a breaking strength of at least about 5 grams/denier. Weaving conditions are selected in order for the seat belt to preserve the stress/strain properties of the yarn and maintain the webbing strength. Our results indicate that the most desirable weaving pattern for energy absorption is a 2×2 twill webbing. The present web provides the desired load-leveling characteristics in the absence of a clamping device such as taught by U.S. Pat. No. 3,486,791; stitching such as taught by U.S. Pat. No. 3,550,957; and a mechanical energy absorbing device such as the constant force retractor taught by commonly assigned U.S. Pat. No. 5,547,143. The present web and yarn provide the desired load-leveling characteristics and are made from material other than the PBT homopolymer taught by Publication 90717. The present web provides the desired load-leveling characteristics by using warp yarns having substantially the same force-displacement profile instead of the plurality of warp yarn force-displacement profiles taught by U.S. Pat. Nos. 3,756,288; 3,823,748; 3,872,895; 4,288,829; and 5,376,440. The present web provides the desired load-leveling characteristics and is made from polymer other than the PET homopolymer taught by U.S. Pat. No. 4,710,423 and Publication 298209. Therefore, contemplated webs comprising the yarns according to the inventive subject matter as particularly useful for seat belts. EXAMPLES The following examples are intended to be illustrative and not limiting to the subject matter. Therefore, numerous components, steps, and/or conditions may be modified without departing from the inventive concept presented herein. Comparative Example (1) Dried PET pellets (IV=0.9; MV=15,000 poises at 280° C.) were fed into a counter-rotation twin screw extruder (diameter=27 mm, length=1404 mm) at the rate of 12 lbs/hr. The length of one zone was about 4 times the screw diameter. The pellets started to melt and were advanced forward by a pumping element. After PET melted, the premixed epsilon-caprolactone and catalyst (tin octonate, 0.09 wt % of PET-caprolactone) were injected by a piston pump into the extruder into the melt at the rate of 4 lbs/hr. A forwarding mixer was located under the injection point. The injected liquid was mixed with PET melt by both distributive and dispersive mixers. The mixture of PET and epsilon-caprolactone was then forwarded into reaction zones and the reaction was completed with a residence time of 3.7 minutes. At the end of polymerization, the melt was devolatilized by a vacuum. The stress-strain curve for the yarn, as well as the seat belt which could be made from that yarn, is shown in FIG. 2A. The extrusion conditions for the comparative example are given in Table I. The polymer melt (e.g., PET (75%)-polycaprolactone (25%)) was then either fed into a spin pot which contained a spinneret to form fibers, or extruded through a three hole die, quenched into water, and cut into pellets. The diblock copolymer had a melting point of 231° C. and an IV=0.98 which demonstrates that the PET copolymerized with epsilon-caprolactone. Chemical composition of the polymers are indicated in Table II. Inventive Example (2) High viscosity molten PET (IV>0.9) was fed from a high viscosity, melt PET reactor directly into the feed of a twin screw extruder. The twin screw extruder in this example is a counter rotating 67 mm twin screw, but co-rotating twin screws have been designed to produce similar results. The high viscosity molten PET was metered precisely to the twin screw extruder by a gear type metering pump at the rate of approximately 252 lb/hour. The twin screw extruder had an overall L/D of approximately 38/1 and was comprised of 5 processing sections: a) molten PET feed, b) co-monomer injection and mixing, c) copolymerization reaction section, d) vacuum stripping of residual monomer, and e) pressure build for discharge. An injection port in the co-monomer injection and mixing section allowed injection of approximately 28 lb/hr of room temperature epsilon-caprolactone, which was precisely metered by high pressure metering pumps. Mixed with the epsilon-caprolactone feed was 0.000275 tin octonate by % weight of the PET/epsilon-caprolactone copolymer. The epsilon-caprolactone was quickly mixed with the PET melt by both distributive and dispersive mixers. The PET and epsilon-caprolactone mixture was then forwarded into the copolymerization reaction zones where the reaction was completed resulting in reaction of at least 95% of all the epsilon-caprolactone. At the end of the polymerization section, the melt was devolatilized by vacuum. The polymer melt (PET (90%)-polycaprolactone (10%)) was then fed pumped from the extruder and fed by means of a transfer pump to spin pumps in parallel. The diblock copolymer had a melting point of at least 220° C. and an IV of about 1.0 IV, which demonstrates that the PET had copolymerized with epsilon-caprolactone. Each of the spin pumps pumped the copolymer through a spinneret with 100 round holes. The filaments went through a heated sleeve and were quenched by uniformly controlled air. The undrawn, spun yarn was coated with a spin finish and taken by a godet at a certain speed before passing to subsequent godet rolls prior to being taken onto a package by a winder. The filament bundle from the first godet, was drawn onto a heated godet at 135° C., and then relax about 8 percent before being entangled and taken onto a package by a winder. The stress-strain curve for the yarn, as well as the seat belt which could be made from that yarn, is shown in FIG. 2B. The yarn in this example demonstrates a similar initial barrier stress (IBS) at low stress, about 1 gram/denier in this example, as is shown in the comparative example above (see also FIG. 2A). This low IBS behavior is highly valuable for shock absorption when used as warp yarn in a web. However, at 1.8 gram/denier stress, the yarn in this example elongates significantly less, to about 7% in this example, as compared to the example shown below where the elongation at 1.8 grams/denier stress is about 17%. Likewise, the total elongation of the current example, as shown in FIG. 2B, is limited to less than 25%. The breaking tensile strength is about 7.3 grams/denier in the current example. Test Procedures Tenacity is measured on an Instron equipped with two grips which hold the yarns at the gauge lengths of 10 inches. The yarn is then pulled by the strain rate of 12 inch/minute, the data are recorded by a load cell, and stress-strain curves are obtained. Tenacity is the breaking strength (in grams) divided by the yarn's denier. Thus, specific embodiments and applications of improved load leveling yarns and webbings have been disclosed. It should be apparent, however, to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the spirit of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements; components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. TABLE I Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Example 1(° C.) 2(° C.) 3(° C.) 4(° C.) 5(° C.) 6(° C.) 7(° C.) 8(° C.) 9(° C.) 10(° C.) 11(° C.) 12(° C.) 13(° C.) 1A 292 290 260 250 250 245 245 240 240 240 252 242 240 1B 292 290 255 255 245 240 240 235 235 235 235 235 235 Residence Screw Melt Melt Vacuum Throughput Residence Time Example Speed (RPM) Torque Temperature (° C.) Pressure (psi) (mbar) (lbs/hr) Time (min) Distribution (min) 1A 150 55 264 90 −750 5 12 Not determined 1B 150 48 256 60 −1000 16 3.7 1 Zone temperature had negligible deviation from set points. TABLE II Unreacted Diblock Transesterifi- ε- ε- Copolymer cation Caprolactone Caprolactone Intrinsic in Diblock Example (%) (%) Viscosity (dl/g) Copolymer (%) 1A 15 0 0.94 6 1B 25 0 0.98 5 | <SOH> BACKGROUND OF THE INVENTION <EOH>A typical vehicle safety seat belt system is intended to restrict the displacement of an occupant with respect to the occupant's seated position within the vehicle when the vehicle experiences a sudden, sharp deceleration (see e.g., commonly assigned U.S. Pat. No. 3,322,163. Most seat belt systems have three main portions: A retractor belt portion, a torso belt portion, and a lap belt portion, and the performance of each belt portion may be characterized by its force-displacement curve. The area under the force-displacement curve is referred to as the energy absorbed by the safety restraint. Current vehicle safety seat belts are made from fully drawn polyethylene terephthalate (“PET”) fiber which is partially relaxed (2.7%) and having a tenacity of at least 7.5 g/denier and is 14% elongation at break. However, various problems exists with current PET fiber seat belts. Among other things, crash studies indicate that after the initial vehicle impact occurs (e.g., speed of about 35 miles/hr), the occupant tends to move forward from his seated position until the belt engages to build restraining forces. As indicated in Prior Art FIG. 1 , the relatively unyielding belt made from PET fiber exerts a load of at least 2000 pounds (about 9000 Newtons) against the occupant so as to cause the occupant to have chest and rib cage injuries at the seat belt torso position and also neck and back injuries when the occupant rebounds and impacts the back structure of the seat assembly. U.S. Government regulation requires that seat belts must withstand loads up to 6,000 lbs. When a car collides at a speed of 35 miles/hour, an impact energy to which an average sized person in the car is subjected is at least 500 Joules on the torso belt. Although the current PET fiber may absorb the impact energy, damage to the vehicle occupant still occurs due to the undesirable force-displacement curve. In 70 milliseconds, an average sized passenger will experience high forces of up to 2,000 pounds (about 9,000 Newtons) as shown in FIG. 1 . In order to absorb the impact energy and to reduce the seat belt load against the vehicle occupant, U.S. Pat. No. 3,550,957 discloses a shoulder harness having stitched doubled sections of the webbing arranged above the shoulder of the occupant so that the stitching permits the webbing to elongate from an initial length toward a final length at a controlled rate under the influence of a predetermined restraining force. However, the stitched sections do not give the desirable amount of energy absorption, do not provide uniform response, and are not reusable. See also U.S. Pat. No. 4,138,157. U.S. Pat. No. 3,530,904 discloses a woven fabric which is constructed by weaving two kinds of yarns having relatively different physical properties and demonstrates energy absorption capability. U.S. Pat. Nos. 3,296,062; 3,464,459; 3,756,288; 3,823,748; 3,872,895; 3,926,227; 4,228,829; 5,376,440; and Japanese Patent 4-257336 further disclose webbings which are constructed of multiple kinds of warp yarns having different tenacity and elongations at break. The webbing shows multiple step gives and impact absorbent characteristics. Those skilled in this technical area have recognized the deficiencies in using at least two different yarn types as taught by the preceding references. U.S. Pat. No. 4,710,423 and Kokai Patent Publication 298209 published Dec. 1, 1989 (“Publication 298209”) teach that when using at least two different yarn types, energy absorption occurs in a stepwise manner and thus, the web does not absorb the energy continuously and smoothly. Therefore, after one type of warps absorbs a portion of the impact energy, and before another type of warps absorbs another portion of the impact energy, the human body is exposed to an undesirable shock. In addition, these types of seat belts are not reusable. U.S. Pat. No. 3,486,791 discloses energy absorbing devices such as a rolled up device which separates a slack section of the belt from the taut body restraining section by clamping means which yield under a predetermined restraining force to gradually feed out the slack section so that the taut section elongates permitting the restrained body to move at a controlled velocity. The reference also describes a device which anchors the belt to the vehicle by an anchor member attached to the belt and embedded in a solid plastic energy absorber. These kinds of mechanical devices are expensive, are not reusable, provide poor energy absorption, and are difficult to control. An improvement on the foregoing devices is taught by commonly assigned U.S. Pat. No. 5,547,143 which describes a load absorbing retractor comprising: a rotating spool or reel, seat belt webbing secured to the reel; and at least one movable bushing, responsive to loads generated during a collision situation, for deforming a portion of the reel and in so doing dissipating a determined amount of the energy. U.S. Pat. No. 4,710,423 and Publication 298209 disclose webbing comprised of PET yarns having tenacity of at least 4 grams/denier and an ultimate elongation of from 50% to 80%. Due to the inherent physical properties of PET yarn, the Examples show that, at 5% elongation, the load has already reached more than 700 kg (about 1500 lbs). The damage to the occupant by seat belt still exists and thus, the belt needs to be further modified. Examples in these two patents also show that if PET yarn is overrelaxed, the tenacity drops to 2.3 g/denier. Kokai Patent Publication 90717 published Apr. 4, 1995 discloses high strength polybutylene terephthalate homopolymer (“PBT”) fiber based energy absorption webbing. The fiber's tenacity is over 5.8 g/denier, breaking elongation is over 18.0%, and the stress at 10% elongation is less than 3.0 g/d. However, this reference fails to teach PBT fiber demonstrating the initial stress requirement which engages the seat belt to protect the occupant and the means to control the initial stress barrier. Consequently, it would be desirable to have an improved energy absorbing seat belt which has a smoother performance than that of the known stitched webbing approach or the known use of at least two different fibers, is reusable unlike the known clamp approach, and also addresses the ability to control the initial barrier stress and the impact energy absorption. U.S. Pat. Nos. 5,830,811; 5,869,582; 6,071,835, 6,057,252 and 6,228,488 describe load leveling yarns, the copolymers from which they are made, the process by which they are made and the webbing in which they are utilized, which satisfy the requirement for a smooth energy absorbing seat belt. Subsequent seat belt development work has elucidated the need for an energy absorbing seat belt which effectively absorbs the initial shock of a rapid deceleration, but with less total elongation as is described by the load leveling yarns of U.S. Pat. No. 5,830,811 and its seat belts. For example, in rapid deceleration situations, occupants of the 95 weight percentile, could in belts more than is acceptable for use in rear seats. It would therefore be desirable to have an improved seat belt with the energy absorbing performance of the load leveling yarns of U.S. Pat. No. 5,830,811, but with lower total elongation at the higher force loads produced by the heaviest occupants. Among other advantages, lower total elongation at higher force loads would prevent excessive excursion of heavier occupants into the back side of the front seats in a rapid deceleration situation. Thus, while numerous compositions and methods for load leveling yarns and webbings are known in the art, all or almost all of them suffer from various disadvantages. Consequently, there is still a need to provide improved load leveling yarns and webbings. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention is directed to yarns with improved force displacement profiles, and to various products formed from such yarns. Especially contemplated products include webs made from, or comprising the yarn, and seat belts comprising contemplated yarns. In one preferred aspect of the inventive subject matter, contemplated yarns have a force displacement profile such that (a) when said yarn is subjected to an initial barrier stress of from about 0.2 gram/denier to less than or equal to about 1.4 grams/denier, said yarn elongates to less than 3 percent and the initial modulus ranges from about 20 grams/denier to about 150 grams/denier, (b) when that yarn is subjected to greater than said initial barrier stress and less than or equal to 1.8 grams/denier, the yarn elongates further to at least about 6 percent and the energy absorbed from 0 to the elongation at 1.8 grams/denier is at least about 0.0008 Joule/denier*meter, and (c) upon subjecting the yarn to greater than 1.8 grams/denier, the modulus increases sharply and the yarn elongates further until the yarn breaks at a tensile strength of at least about 5 grams/denier, wherein said yarn comprises a multiplicity of fibers, all of said fibers have substantially the same force-displacement profile, are made from polymers having a glass transition temperature in the range from about −10° C. to about +60° C., and are not made from polybutylene terephthalate homopolymer. In further preferred aspects, the yarn may be fabricated from homopolymers (e.g., polytrimethylene terephthalate, polyisobutylene terephthalate, long chain alkylene terephthalate, or naphthalate polymers), or random copolymers, diblock copolymers, triblock copolymers, or segmented block copolymers, which will preferably include an aromatic polyester segment (e.g., PET, PEN, etc.) and a lactone monomer (e.g., epsilon-caprolactone, propiolactone, butyrolactone, or valerolactone). The lactone monomer is preferably present from about 5 to about 45 weight percent, and even more preferably from about 8 to about 15 weight percent. Various objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the invention. | 20040109 | 20060131 | 20050714 | 59036.0 | 0 | EDWARDS, NEWTON O | LOAD LEVELING YARNS AND WEBBINGS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,754,454 | ACCEPTED | Method of making wall block | A method of making a wall block and a mold box therefore. The wall block design maximizes the use of the mold box. The method produces wall blocks having a large surface area front face compared to the front face size of prior art blocks. The blocks have about one third more front surface area. This results in faster construction of walls and a faster construction sequence. The method of making the blocks makes efficient use of mold space and material, resulting in higher production yields and/or higher total daily production square footage. | 1. A mold box for making first and second wall blocks comprising: first and second opposed end rails and first and second opposed side rails, the end rails and side rails together forming a mold cavity, the first and second end rails being spaced apart a distance d1, the first and second side rails being spaced apart a distance d2 which is less than distance d1; and a divider plate having a first end connected to the first end rail and a second end connected to the second end rail, the divider plate dividing the mold cavity into a first mold section for forming the first block and a second mold section for forming the second block. 2. A mold box for making first and second wall blocks comprising: first and second opposed end rails and first and second opposed side rails, the end rails and side rails together forming a mold cavity, the first and second end rails being spaced apart a distance d1, the first and second side rails being spaced apart a distance d2 which is less than distance d1; and a divider plate having a first end connected to the first end rail and a second end connected to the second end rail, the divider plate dividing the mold cavity into a first mold section for forming the first block and a second mold section for forming the second block, the first mold section being configured such that a front face of the first block is formed adjacent the first side rail, the second mold section being configured such that a front face of the second block is formed adjacent the second side rail. 3. The mold box of claim 3 wherein distance d1 is about 24 inches (61 cm) and distance d2 is about 18 inches (45.7 cm). 4. The mold box of claim 3 wherein the mold box has a thickness defined by a distance d3, wherein distance d3 is less than distance d2. 5. The mold box of claim 4 wherein distance d3 is 8 inches (20.3 cm). 6. A mold box for making first and second wall blocks comprising: first and second opposed end rails and first and second opposed side rails, the end rails and side rails together forming a mold cavity, the first and second end rails being spaced apart a distance d1, the first and second side rails being spaced apart a distance d2 which is less than distance d1; and a divider plate having a first end connected to the first end rail and a second end connected to the second end rail, the divider plate dividing the mold cavity into a first mold section for forming the first block and a second mold section for forming the second block, the first mold section being configured such that a front face of the first block is formed adjacent the first side rail, the second mold section being configured such that a front face of the second block is formed adjacent the second side rail, the divider plate being shaped in a non-planar configuration such that a maximum first block depth measured between the first side rail and the divider plate along a line generally perpendicular to the first side rail is greater than d2/2 and a maximum second block depth measured between the second side rail and the divider plate along a line generally perpendicular to the second side rail is greater than d2/2. 7. A method of making wall blocks comprising: providing a mold box having first and second opposed end rails and first and second opposed side rails, the end rails and side rails together forming a mold cavity, the first and second end rails being spaced apart a distance d1, the first and second side rails being spaced apart a distance d2 which is less than distance d1; dividing the mold cavity into a first mold section for forming a first block and a second mold section for forming a second block, the first mold section being configured such that a front face of the first block is formed adjacent the first side rail, the second mold section being configured such that a front face of the second block is formed adjacent the second side rail; filling the first and second mold sections with a desired block material; and removing the block material from the first mold section to form the first block and from the second mold section to form the second block, the first block having a maximum depth measured between the front face and a rear face along a line generally perpendicular to the front face which is greater than d2/2 and the second block having a maximum depth measured between the front face and a rear face along a line generally perpendicular to the front face which is greater than d2/2. 8. A method of making wall blocks comprising: providing a mold box having first and second opposed end rails and first and second opposed side rails, the end rails and side rails together forming a mold cavity, the first and second end rails being spaced apart a distance d1, the first and second side rails being spaced apart a distance d2 which is less than distance d1; dividing the mold cavity into a first mold section for forming a first block and a second mold section for forming a second block, the first mold section being configured such that a front face of the first block is formed adjacent the first side rail, the second mold section being configured such that a front face of the second block is formed adjacent the second side rail; filling the first and second mold sections with a desired block material; and removing the block material from the first mold section to form the first block and from the second mold section to form the second block, the front faces of the first and second blocks each having a length approximately equal to d1. 9. A method of making wall blocks comprising: providing a mold box having first and second opposed end rails and first and second opposed side rails, the end rails and side rails together forming a mold cavity, the first and second end rails being spaced apart a distance d1, the first and second side rails being spaced apart a distance d2 which is less than distance d1; connecting a divider plate between the first and second end rails to divide the mold cavity into a first mold section for forming a first block and a second mold section for forming a second block, the first mold section being configured such that a front face of the first block is formed adjacent the first side rail, the second mold section being configured such that a front face of the second block is formed adjacent the second side rail; filling the first and second mold sections with a desired block material; and removing the block material from the first mold section to form the first block and from the second mold section to form the second block. 10. A method of making wall blocks comprising: providing a mold box having first and second opposed end rails and first and second opposed side rails, the end rails and side rails together forming a mold cavity, the first and second end rails being spaced apart a distance d1, the first and second side rails being spaced apart a distance d2 which is less than distance d1; connecting a divider plate between the first and second end rails to divide the mold cavity into a first mold section for forming a first block and a second mold section for forming a second block, the first mold section being configured such that a front face of the first block is formed adjacent the first side rail, the second mold section being configured such that a front face of the second block is formed adjacent the second side rail, the divider plate being non-planar and having a first mold surface and a second mold surface, a rear face of the first block being formed adjacent the first mold surface and a rear face of the second block being formed adjacent the second mold surface, the divider plate being configured such that the rear faces of the first and second blocks overlap when they are formed in the mold cavity; filling the first and second mold sections with a desired block material; and removing the block material from the first mold section to form the first block and from the second mold section to form the second block. 11. A wall block comprising: a front portion including opposed top and bottom surfaces, opposed side surfaces and a front surface, the front surface having a length equal to the distance between the side surfaces and a height equal to the distance between the top and bottom surfaces; and at least one leg extending from the front portion in a direction opposite the front surface and having a rear surface, a distance between the front surface and rear surface comprising a maximum block depth, the at least one leg being positioned such that when a plurality of the blocks including first and second blocks are packaged for shipment the first and second blocks can be positioned on a common surface with their front surfaces oriented in opposite directions and with the at least one leg of the first block overlapping the at least one leg of the second block so that the first and second blocks occupy an area on the common surface which is less than the length of the front surface times twice the maximum block depth. 12. A wall block comprising: a front portion including opposed top and bottom surfaces, opposed side surfaces and a front surface, the front surface having a length equal to the distance between the side surfaces and a height equal to the distance between the top and bottom surfaces; and at least one leg extending from the front portion in a direction opposite the front surface and having a rear surface, the at least one leg being positioned such that when a wall is formed from multiple courses of the blocks which are offset from course to course by about one half the length of the front surface the legs in each course of blocks align vertically. | This application is a continuation-in-part of application Ser. No. 29/186,712, filed Jul. 21, 2003, hereby incorporated herein by reference. FIELD OF THE INVENTION The present invention relates to retaining wall blocks and a method for making these blocks. BACKGROUND OF THE INVENTION Numerous methods and materials exist for the construction of retaining walls. Such methods include the use of natural stone, poured in place concrete, masonry, and landscape timbers or railroad ties. In recent years, segmental concrete retaining wall units which are dry stacked (i.e., built without the use of mortar) have become a widely accepted product for the construction of retaining walls. Such products have gained popularity because they are mass produced, and thus relatively inexpensive. They are structurally sound, easy and relatively inexpensive to install, and couple the durability of concrete with the attractiveness of various architectural finishes. It is desirable to build a wall from such blocks quickly and without the need for special skilled labor. The efficiency of building a wall can be measured by determining how fast the front face of a wall is constructed. Clearly, this depends on the size of the blocks used and ease of stacking the blocks. It is standard practice in the prior art to use similarly sized mold boxes to produce various styles of block. For example, a standard size box has a block molding area of about 18 inches by about 24 inches (about 45.7 cm by about 61 cm), and produces a block about 8 inches (20.3 cm) thick. FIG. 1A illustrates retaining wall block B1 in mold box M. This block is symmetrical about a centrally located vertical plane of symmetry. Block B1 has pin holes PH, pin receiving cavities PC, and two cores C1 and C2. The sides generally converge from the front to the back of the block. Front face F is produced by the removal of waste portion W after the block has formed. This portion is split off to form a roughened surface. The block of FIG. 1A is manufactured one block at a time so that the yield per cycle is one square foot (1 sq ft or 929 sq cm) of front face. A typical weight for this block is about 110 lbs (50 kg). Other prior art blocks are shown in FIGS. 1B and 1C in mold box M. This block is similar to that described in WO 02/101157 (MacDonald et al.). This block also has similarities to block B1, as it is symmetrical about a centrally located vertical plane of symmetry. Block B2 has pin holes PH, pin receiving cavities PC, and core C. Preferably, the blocks are formed so that front face F will have a roughened appearance. Block B2 is made in a mold box two at one time. This provides a good use of mold space, producing about two square feet (1858 sq cm) of front face per manufacturing cycle. FIG. 1B illustrates that the blocks can be formed two at a time and separated at the back faces. In this case, the front surface of the block is textured by texturing elements T that contact the front surface as the block is removed from the mold box. FIG. 1C shows blocks that are molded together at front face F. The front faces of these blocks will be separated, or split apart after curing. The splitting of such blocks is used to form the desirable surface appearance. When manufactured in this manner, each block has a front face of about one square foot (1 sq ft or 929 sq cm). Thus, the yield per cycle is two square feet of front face. A typical weight for this block is about 85 lbs (38.6 kg). A third type of prior art block in its mold box M is shown in FIG. 1D. Block B3 is a rectangular block, shown having two cores or cavities C. The long dimension of the block typically is used to form the face of a wall. Thus, this type of block produces a useful front surface about 24 inches long, rather than the 18 inch long surface of blocks B1 and B2. The surface area (for the same thickness block, i.e., about 8 inches) is about 33% greater than the surface area of blocks B1 or B2. However, this block weighs about 250 lbs (113.6 kg) and must be set in place using mechanized means. Accordingly, a need in the art remains for wall blocks that make the most use of a mold box's area while producing a block with a large front surface area. SUMMARY OF THE INVENTION The present invention is a mold box and a method of making a wall block that maximizes the use of the mold box and produces wall blocks having a large surface area front face that are lightweight and easy to handle when constructing a wall. This results in faster construction of walls and a faster construction sequence, because for each block, the front face surface area is larger than blocks known in the art. The method of making the blocks makes efficient use of mold space and material, resulting in higher production yields and/or higher total daily production square footage. In one aspect, this invention is a mold box for making first and second wall blocks comprising first and second opposed end rails and first and second opposed side rails, the end rails and side rails together forming a mold cavity, the first and second end rails being spaced apart a distance d1, the first and second side rails being spaced apart a distance d2 which is less than distance d1; and a divider plate having a first end connected to the first end rail and a second end connected to the second end rail, the divider plate dividing the mold cavity into a first mold section for forming the first block and a second mold section for forming the second block. In another aspect, this invention is a mold box for making first and second wall blocks comprising first and second opposed end rails and first and second opposed side rails, the end rails and side rails together forming a mold cavity, the first and second end rails being spaced apart a distance d1, the first and second side rails being spaced apart a distance d2 which is less than distance d1; and a divider plate having a first end connected to the first end rail and a second end connected to the second end rail, the divider plate dividing the mold cavity into a first mold section for forming the first block and a second mold section for forming the second block, the first mold section being configured such that a front face of the first block is formed adjacent the first side rail, the second mold section being configured such that a front face of the second block is formed adjacent the second side rail. In another aspect, this invention is a mold box for making first and second wall blocks comprising first and second opposed end rails and first and second opposed side rails, the end rails and side rails together forming a mold cavity, the first and second end rails being spaced apart a distance d1, the first and second side rails being spaced apart a distance d2 which is less than distance d1; and a divider plate having a first end connected to the first end rail and a second end connected to the second end rail, the divider plate dividing the mold cavity into a first mold section for forming the first block and a second mold section for forming the second block, the first mold section being configured such that a front face of the first block is formed adjacent the first side rail, the second mold section being configured such that a front face of the second block is formed adjacent the second side rail, the divider plate being shaped in a non-planar configuration such that a maximum first block depth measured between the first side rail and the divider plate along a line generally perpendicular to the first side rail is greater than d2/2 and a maximum second block depth measured between the second side rail and the divider plate along a line generally perpendicular to the second side rail is greater than d2/2. In another aspect, this invention is a method of making wall blocks comprising providing a mold box having first and second opposed end rails and first and second opposed side rails, the end rails and side rails together forming a mold cavity, the first and second end rails being spaced apart a distance d1, the first and second side rails being spaced apart a distance d2 which is less than distance d1; dividing the mold cavity into a first mold section for forming a first block and a second mold section for forming a second block, the first mold section being configured such that a front face of the first block is formed adjacent the first side rail, the second mold section being configured such that a front face of the second block is formed adjacent the second side rail; filling the first and second mold sections with a desired block material; and removing the block material from the first mold section to form the first block and from the second mold section to form the second block, the first block having a maximum depth measured between the front face and a rear face along a line generally perpendicular to the front face which is greater than d2/2 and the second block having a maximum depth measured between the front face and a rear face along a line generally perpendicular to the front face which is greater than d2/2. In another aspect, this invention is a method of making wall blocks comprising providing a mold box having first and second opposed end rails and first and second opposed side rails, the end rails and side rails together forming a mold cavity, the first and second end rails being spaced apart a distance d1, the first and second side rails being spaced apart a distance d2 which is less than distance d1; dividing the mold cavity into a first mold section for forming a first block and a second mold section for forming a second block, the first mold section being configured such that a front face of the first block is formed adjacent the first side rail, the second mold section being configured such that a front face of the second block is formed adjacent the second side rail; filling the first and second mold sections with a desired block material; and removing the block material from the first mold section to form the first block and from the second mold section to form the second block, the front faces of the first and second blocks each having a length approximately equal to d1. In another aspect, this invention is a method of making wall blocks comprising providing a mold box having first and second opposed end rails and first and second opposed side rails, the end rails and side rails together forming a mold cavity, the first and second end rails being spaced apart a distance d1, the first and second side rails being spaced apart a distance d2 which is less than distance d1; connecting a divider plate between the first and second end rails to divide the mold cavity into a first mold section for forming a first block and a second mold section for forming a second block, the first mold section being configured such that a front face of the first block is formed adjacent the first side rail, the second mold section being configured such that a front face of the second block is formed adjacent the second side rail; filling the first and second mold sections with a desired block material; and removing the block material from the first mold section to form the first block and from the second mold section to form the second block. In another aspect, this invention is a method of making wall blocks comprising providing a mold box having first and second opposed end rails and first and second opposed side rails, the end rails and side rails together forming a mold cavity, the first and second end rails being spaced apart a distance d1, the first and second side rails being spaced apart a distance d2 which is less than distance d1; connecting a divider plate between the first and second end rails to divide the mold cavity into a first mold section for forming a first block and a second mold section for forming a second block, the first mold section being configured such that a front face of the first block is formed adjacent the first side rail, the second mold section being configured such that a front face of the second block is formed adjacent the second side rail, the divider plate being non-planar and having a first mold surface and a second mold surface, a rear face of the first block being formed adjacent the first mold surface and a rear face of the second block being formed adjacent the second mold surface, the divider plate being configured such that the rear faces of the first and second blocks overlap when they are formed in the mold cavity; filling the first and second mold sections with a desired block material; and removing the block material from the first mold section to form the first block and from the second mold section to form the second block. In another aspect, this invention is a wall block comprising a front portion including opposed top and bottom surfaces, opposed side surfaces and a front surface, the front surface having a length equal to the distance between the side surfaces and a height equal to the distance between the top and bottom surfaces. The at least one leg extends from the front portion in a direction opposite the front surface and has a rear surface, a distance between the front surface and rear surface comprising a maximum block depth. The at least one leg is positioned such that when a plurality of the blocks including first and second blocks are packaged for shipment the first and second blocks can be positioned on a common surface with their front surfaces oriented in opposite directions with the at least one leg of the first block overlapping the at least one leg of the second block so that the first and second blocks occupy an area on the common surface which is less than the length of the front surface times twice the block depth. In another aspect, the invention is a wall block comprising a front portion including opposed top and bottom surfaces, opposed side surfaces and a front surface, the front surface having a length equal to the distance between the side surfaces and a height equal to the distance between the top and bottom surfaces. The at least one leg extends from the front portion in a direction opposite the front surface and has a rear surface, the at least one leg being positioned such that when a wall is formed from multiple courses of the blocks which are offset from course to course by about one half the length of the front surface the legs in each course of blocks align vertically. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is plan view of the mold box configuration for a first Prior Art block. FIG. 1B is a plan view of a first mold box configuration for a second Prior Art block. FIG. 1C is a plan view of a second mold box configuration for a second Prior Art block. FIG. 1D is a plan view of a mold box configuration for a third Prior Art block. FIG. 2 is a plan view of the configuration of the block of this invention in a mold box. FIG. 3 is a perspective view of the block of this invention. FIG. 4A is a top view and FIG. 4B is a bottom view of the block of FIG. 2. FIGS. 5A and 5B are side views of the block of FIG. 2. FIG. 6 is a back view of the block of FIG. 2. FIG. 7 is a perspective view showing stacked blocks of FIG. 2. FIG. 8A is a perspective view and FIG. 8B is a top view of another block of this invention. FIG. 9 is a perspective view of another block of this invention. FIG. 10 is a top view of the block of FIG. 9. FIG. 11 is a perspective view of another block of this invention. FIG. 12 is a top view of a mating pair of the blocks of FIG. 11. FIGS. 13A and 13B are partial top views of a row of blocks comprising the blocks of FIGS. 9 and 11. FIG. 14 is a partial view of a wall of blocks constructed with the blocks of FIGS. 9 and 11. FIG. 15A is a bottom perspective view of another block of this invention. FIG. 15B a top perspective view of stacked blocks of FIG. 15A. FIG. 16 is a side view of the block of FIG. 15A. FIG. 17 is a top view of another block of this invention. FIG. 18 is a top view of two other blocks of this invention. FIGS. 19A and 19B are partial cross sectional views of a block showing pin placement in a pin hole. FIGS. 20A and 20B are cross sectional views of walls constructed from the blocks of this invention. FIG. 21 is a perspective view of a mold box used to form the blocks of this invention. FIG. 22A is a plan view of the mold box of FIG. 21 showing the divider plate and FIG. 22B is a plan view of the divider plate with the mold box and the blocks in phantom. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS In this application, “upper” and “lower” refer to the placement of the block in a retaining wall. The lower surface faces down, that is, it is placed such that it faces the ground. In forming a retaining wall, one row of blocks is laid down, forming a course. A second course is laid on top of this by positioning the lower surface of one block on the upper surface of another block. The blocks of this invention may be made of a rugged, weather resistant material, such as concrete, especially if the wall is constructed outdoors. Other suitable materials include plastic, reinforced fibers, and any other materials suitable for use in molding wall blocks. The surface of the blocks may be smooth or may have a roughened appearance, such as that of natural stone. The blocks are formed in a mold and various textures can be formed on the surface, as is known in the art. Several embodiments are illustrated in the figures below. In one embodiment, this invention is a block comprising a front portion having two legs extending therefrom. The two legs each have a core and a back portion and the back face of each back portion is the back of the block. The cores are optional and their positions can be varied. The legs are located asymmetrically on the block. The legs have sides that define the area of the core and the leg side walls generally converge from the front toward the back. In another embodiment, this invention is a block similar to the block described above, except that one of the legs joins the front portion at right angles. This block is suitable for forming a corner structure. In another embodiment, this invention is a block having one leg extending from the front face where the leg is located at one side of the front face. In another embodiment, this invention is a block having multiple curvilinear legs, all legs extending away from the front surface. The blocks of this invention may be provided with a connection means for connecting blocks in adjacent courses. The connection means may comprise pin holes and pin receiving cavities. The cavities in a second or top block accept the head of a pin placed in a pin hole of a first or bottom block. Alternatively, the bottom surface of this block may be provided with a channel configured to accept the head of a pin placed in a pin hole in an underlying block. The appearance of the front face of the block may be varied as desired. The advantage to the design of blocks described herein is that the blocks provide good structural stability with a maximum amount of block front face and a minimum use of material. Not only are the blocks easy to handle, but the manufacture of the blocks is efficient in its use of space and material, which can be seen, for example, by the illustration of FIGS. 22A and 22B, discussed further below. The blocks are made by forming matching pairs of blocks in a single mold designed so that one or more legs on a first block interweave or overlap with one or more legs on a second block. In this way the blocks nest together. The length of the front face of the block is generally about twice the distance from the front of the block to the back face of a leg. This has been found to maximize the volume of mold space used. Molding the blocks in this manner is also an advantage when it comes to shipping the blocks since the blocks are removed from the mold, pallatized and shipped in the same overlapping or nested configuration. This overlapping configuration takes up less space and is easier to handle than blocks molded in a conventional manner. The depth of the block (i.e., the distance from front to back surfaces) is greater than half the mold box depth. It should be understood, however, that other lengths or dimensional relationships of the blocks can be used within the scope of the invention. This block design maximizes the area of the front face of the block while minimizing the weight of the block. As a result, the block manufacturer is able to produce more wall area per manufacturing or mold cycle and gain greater yield of wall blocks per a given volume of raw materials while at the same time manufacturing the blocks in a configuration which saves space and is easy to handle and to ship. The wall installer is able to install more face area of wall each time a block is placed and the blocks generally weigh no more or just slightly more than prior art blocks having a smaller front surface area. It is useful to compare the block of the present invention to prior art blocks, such as those illustrated in FIGS. 1A to 1D above. FIG. 2 shows the present inventive blocks 100 in a mold box. This figure can be compared directly with FIGS. 1A to 1D. The mold box illustrated is a standard size for the industry, about 18 by 24 inches, and produces a block about 8 inches thick. Blocks 100 each weigh about 95 lbs (43.2 kg). The front surface (F) of the block is the dimension of the long dimension of the mold box, i.e., about 24 inches. Thus this block has a larger surface area (24 by 8 inches, 192 sq in, or 1.33 sq ft) than the surface area (18 by 8 inches, 144 sq in, or 1 sq ft) of the prior art blocks shown in FIGS. 1A to 1C. This equals a 33% increase in front surface area. Yet the weight increases only about 11%, to 95 lbs from 85 lbs (43.2 to 38.6 kg), still a handleable weight. In addition, an even greater manufacturing advantage is realized because the inventive blocks are made two at a time. Thus, one production cycle produces 2.66 sq ft (2470 sq cm) of front surface area per manufacturing cycle. This compares to the production of one sq ft for Prior Art block B1, two sq ft for Prior Art block B2, and 1.33 sq ft. for Prior Art block B3. In addition, in all cases for the present block, the capacity of the mold box is maximized or at least increased substantially. Various embodiments of the blocks of this invention are shown in the drawings. FIGS. 3 to 7 illustrate block 100. FIGS. 8A and 8B illustrate block 100a, which is substantially similar to block 100 except that block 100a has rounded corners and fewer pin holes. Similar features of these blocks will be referred to by the same numbers. Block 100 has parallel top face 102 and bottom face 103. Front face 104 has optional bevel or chamfer 108 adjacent the top and sides of the block to provide a desirable appearance. The length of face 104 is defined by the distance between corners 106 and 107. Extending from front portion 110 are two legs 120 and 130. Cores 121 and 131 are located primarily in the legs, though they extend into front portion 110. It should be noted that the shape of the cores as shown in the figures is a convenient shape for manufacturing, however, any suitable shape can be used. Legs 120 and 130 extend to rear portions 124 and 134, respectively, having rear faces 125 and 135, respectively. Front face 104 and rear faces 125 and 135 each extend from top face 102 to bottom face 103, as shown in FIG. 6. The distance between faces 102 and 103 defines the thickness of the block. Legs 120 and 130 are separated by void 140. Each leg 120 and 130 has two side walls 122, 123 and 132, 133, respectively. These side walls generally converge from the front to the back of the block. The side walls extend from top face 102 to bottom face 103. In a preferred embodiment, legs 120 and 130 are positioned such that, when stacking blocks one on top of another in a wall, a leg of one block is placed over a leg in an underlying block and a running bond pattern is created. The alignment of legs is desirable because it adds to the structural stability of a wall, and also permits the introduction of vertical reinforcement or filler materials that would extend through the cores and voids of adjacent legs. Side 111 of block 100 is shown in FIG. 5A and side 113 is shown in FIG. 5B. Side 111 comprises the side surfaces of leg side wall 122 and back portion 124, and the side of front portion 110. Side 113, as shown in FIG. 5B, comprises the side surfaces of leg side wall 133 and back portion 134, and the side of front portion 110. Front portion 110 (FIG. 3) includes front face 104 and also includes pin holes 112, 114, 115, and 116 and pin receiving cavities 117 and 118 (FIG. 4A). It should be noted that the shape of the cores as shown in FIGS. 3 to 8 is a convenient shape for manufacturing, however, any suitable shape can be used. The cores serve to reduce the weight of the block. When a block is manufactured, a core is tapered from top to bottom to ease stripping the block from the mold, as known to one of skill in the art. Cores are optional but may be desirable since they reduce the amount of material required to make the block, and they allow more blocks to be shipped since weight is usually a constraint on how many blocks may be shipped at one time. In addition, a lower weight block is easier for those who handle the block when constructing a wall. Further, the size and shape of the legs and voids can be varied. Pin receiving cavities 117 and 118 are positioned at any desired location along the front portion of the block and may have any desired shape. The placement of cavities in conjunction with pin holes 115 and 116 can be used to form a running-bond pattern in a wall of blocks. The pin receiving cavities may extend from the top to the bottom of the block, which aids in minimizing block weight, or may only partially extend toward the bottom of the block. However, they also could be depressions in the block rather than passageways. Pin holes 112, 114, 115 and 116 extend from the top face 102 to bottom face 103. Four pin holes are shown, but more or fewer pin holes may be used. The holes are tapered to ease the removal of forming elements from the molded block. These pin holes are sized to receive a connecting element, such as a pin. The pin may be a shouldered pin, in which case the pin hole may be substantially the same diameter for the thickness of the block, or the pin holes may be truncated to allow a portion of a headless pin to sit above the surface of the block. Various pins are described further below. Block 100 is shown stacked in a running bond pattern in FIG. 7. These blocks are configured so that the back portion of a block above rests on at least a part of the back portion of the block below. Optimally, a leg of one block is placed on the leg of an underlying block. This adds stability to a wall formed from these blocks and increases the frictional connection of the blocks. Block 100a in FIGS. 8A and 8B is similar to block 100, having curvilinear back portions 124a and 134a that extend from legs 120 and 130. Curvilinear shapes frequently are more desirable due to the ease of removal of the block from a mold. FIGS. 9 and 10 illustrate another embodiment of the block. Block 200 is similar to blocks 100 and 100a of FIGS. 3 to 8, except that there are no chamfers on the front of the block. The absence of chamfered edges and corners is that the top and the bottom of the block are interchangeable, that is, if block 200 is flipped over, it is a mirror image of another block 200. By contrast, the mirror image of block 100 would have to be manufactured separately if it is desired to use the block in more than one orientation when constructing a retaining wall. FIGS. 9 and 10 show block 200 having parallel top face 202 and bottom face 203. The length of face 204 is defined by the distance between corners 206 and 207. Extending from front portion 210 are two legs 220 and 230. Cores 221 and 231 are located primarily in the legs, though they extend into front portion 210. Legs 220 and 230 extend to rear portions 224 and 234, respectively, having rear faces 225 and 235, respectively. Front face 204 and rear faces 225 and 235 each extend from top face 202 to bottom face 203. The distance between faces 202 and 203 defines the thickness of the block. Legs 220 and 230 are separated by void 240. Each leg 220 and 230 has two side walls 222, 223 and 232, 233, respectively, generally converging from the front to the back of the block. Block side walls 211 and 213 extend from top face 202 to bottom face 203. Pin holes 215 and 216 and pin receiving cavities 217 and 218 are located on the front portion of the block. FIGS. 11 and 12 illustrate another embodiment of the block of this invention and FIG. 12 shows how the blocks form a mating pair. FIGS. 13A, 13B and 14 show block 300 along with block 200 in a course of blocks and in a wall. Block 300 is similar to block 200, but one of the legs forms right angles at the front and the back of the block. Since there are no chamfers on the front of the block, the block can be used in any orientation, i.e., the bottom and top surfaces are interchangeable. Block 300 has parallel top face 302 and bottom face 303. Face 304 extends between corners 306 and 307. Extending from front portion 310 are two legs 320 and 330. Cores 321 and 331 are located primarily in the legs, though they extend into front portion 310. Legs 320 and 330 extend to rear portions 324 and 334, respectively, having rear faces 325 and 335, respectively. Front face 304 and rear faces 325 and 335 each extend from top face 302 to bottom face 303. The distance between faces 302 and 303 defines the thickness of the block. Legs 320 and 330 are separated by void 340. Each leg 320 and 330 has two side walls 322, 323 and 332, 333, respectively. Leg side wall 322 joins front portion 310 and back portion 324 at right angles. Therefore, side 311 is perpendicular to the front face 304 and back face 325. Side 313 is substantially similar to side 213 in block 200. Side walls 332 and 333 generally converging from the front to the back of the block. The side walls extend from top face 302 to bottom face 303. Pin holes 315 and 316 and pin receiving cavities 317 and 318 are located on the front portion of the block. FIGS. 13A and 13B show blocks 200 and 300 in a course of blocks for the construction of a wall. FIG. 13A shows course 980, in which block 300 is used as the corner block in the orientation as shown in FIGS. 11 and 12. Block 300 is flipped over in FIG. 13B, which shows course 981. During construction of a wall, courses 980 and 981 would be adjacent so that the wall would have an offset or running bond pattern. FIG. 14 shows wall 985 formed from these two types of blocks. FIGS. 15A and 15B show another block embodiment, in which pin receiving cavities are absent and the front portion of the block is provided with a channel. FIGS. 15A and 15B illustrate the bottom and top perspective views of block 400. In FIG. 15A, the block is shown in the orientation as it is manufactured, that is, with the bottom surface facing up, and FIG. 16 shows a side view of the block, with pin holes and core shown in phantom. FIG. 15B shows the block stacked together with other blocks. Block 400 has parallel top face 402 and bottom face 403. Front face 404 extends between chamfered corners 406 and 407 and has chamfered top edge 408. Extending from front portion 410 are two legs 420 and 430. Cores 421 and 431 are located primarily in the legs, though they extend into front portion 410. Legs 420 and 430 extend to rear portions 424 and 434, respectively, having rear faces 425 and 435, respectively. Front face 404 and rear faces 425 and 435 each extend from top face 402 to bottom face 403. The distance between faces 402 and 403 defines the thickness of the block. Legs 420 and 430 are separated by void 440. Each leg 420 and 430 has two side walls 422, 423 and 432, 433, respectively, generally converging to the back surfaces. Side 411 comprises the side surface of side wall 422 and the side of front portion 410. Similarly, side 413 comprises the side surface of side wall 433 and the side of front portion 410 and has a complex geometry. Side walls 432 and 433 generally converge from the front to the back of the block. The side walls extend from top face 402 to bottom face 403. FIG. 15B shows the top perspective view of block 400, illustrating that there are two pin holes. Pin holes 415a, 415b, 416a and 416b are located on the front portion of the block. A set of pinholes (e.g., 415a and 415b) are aligned in a plane generally perpendicular to the front face of block 400; this same plane passes through the core (e.g., core 421). It is to be noted, however, that the pin hole position may be varied as desired. Channel 444 spans the length of the block on the bottom surface near the front face. Channel 444 is configured to receive the head of a pin extending from a pin hole in a block underneath. FIG. 15B also illustrates that back portion 424 rests on back portion 434 of an underlying block. This coincidence of back portions adds to the stability of a wall. FIG. 16 shows pin holes in phantom and illustrates that pin holes 416a and 416b extend from the top to the bottom of the block with substantially the same diameter, though it is to be noted that passageways through a block thickness typically taper from the bottom to the top in the block (as-manufactured), for ease of removal of mold elements. FIG. 16 also shows pin hole 416a opens into channel 444. This type of pin hole is used with shouldered pins, to that the head of the pin lies within the channel. Another embodiment of the block of this invention is shown in FIG. 17. The block is similar to the block embodiments described above and has correspondingly similar elements, and not every element is numbered for this block. Block 500 has one leg 520 extending from front portion 510 to back portion 524. Leg 520 comprises two side walls 522 and 523, which join together with the front and back portions to form core 521. The core is optional but preferred because it results in a lower weight block. Pin holes 515 and 516 and pin receiving cavities 517 and 518 are located near the front face of the block. FIG. 17 demonstrates that a pair of blocks can be formed in the mold such that mold space is maximized. Convenient dimensions for block 500 are those in which the front face is about 24 inches (60.1 cm) wide and 8 inches (20.3 cm) high. The depth of the front portion is about 4 inches (10.1 cm), and the depth of leg 520 is about 8 inches (20.3 cm). Blocks 600 and 700 are shown as a mating pair in FIG. 18 and for clarity are shown moved apart from their position in a mold box. The formation of a mating pair results in one block having three legs (620, 630, 680) and the other having four legs (720, 730, 780, 790). Each leg has a core (621, 631, 681 and 721, 731, 781, and 791 respectively). Block 600 is provided with pin holes (615a/615b, 616a/616b) and channel 644 that extends the length of the block on its bottom surface. Similarly, block 700 is provided with pin holes (715a/715b, 716a/716b) and channel 744 that extends the length of the block on its bottom surface. The legs have a curvilinear shape. The legs of block 600 extend from the front portion in equally spaced intervals, essentially dividing the block into thirds. FIG. 18 illustrates that blocks having this curvilinear shape can be formed in a matching pair, thus maximizing the mold space and minimizing the amount of material needed for each block. Regardless of the block embodiment, various pin configurations can be used, and two are shown in FIGS. 19A and 19B. If it is desirable to use a straight pin, the pin hole should be tapered or truncated so that the pin will not slide to the bottom of the block. Thus, as shown in FIG. 19A, pin 840 is in pin hole 116 of block 100. The pin hole is provided with a taper about half way through the thickness of the block. FIG. 19B shows pin 850 having head 852 attached to straight portion 854. Head 852 rests on the top surface of block 400. Pin hole 416b has substantially the same diameter throughout the thickness of the block. FIG. 20A shows a cross sectional view of a wall wherein blocks are stacked on top of each other, interlocked by pins 850, which are placed in forward pin hole 815. Head 852 fits within a channel (e.g., channel 444 in block 400) on the bottom surface of a block above. This arrangement produces a substantially vertical wall. FIG. 20B illustrates a wall in which blocks are set back from each other by placing pin 850 in the rearward pin hole of an underlying block. A wall having positive set back is frequently desirable because of both appearance and structural stability. FIGS. 21, 22A, and 22B illustrate mold box 900, having first and second opposing end rails 902 and first and second opposing side rails 904. The first and second end rails are spaced apart a distance d1 and the first and second side rails are spaced apart a distance d2. Distance d2 is less than distance d1. A third distance, d3, is the height of the mold box and defines the thickness of the block. The mold box sits on a bottom plate (not shown). The bottom plate, end rails and side rails together form a cavity in which blocks are molded. In order to form the blocks of this invention, the mold box is prepared by installing divider plate 950. The divider plate thus forms first and second mold sections in the mold cavity. This plate preferably is machined from steel into the desired shape and dimensions and is bolted at either end to each side rail. FIG. 22A shows the divider plate bolted into mold box 900 with bolts 955. FIG. 22B shows the divider plate with the bolts, the mold box, and the blocks shown in phantom. Forming elements (not shown) for the cores, pin holes, and pin receiving cavities are hung over the mold box, and a concrete mix is poured into the mold box. The box is vibrated to compact the concrete mix, which solidifies it. The blocks can then be pressed out of the mold box, and away from the divider plate and forming elements, by a stripping shoe or head that presses on the block as the bottom plate moves away. The stripping shoe is designed to pass over all the forming elements and the divider plate to facilitate removal of the block. The block, on the bottom plate, is then moved, typically by a conveyor belt, to an oven, where it is heat cured. Typically, the blocks are shipped in the same orientation in which they are manufactured. This is desirable because each handling step increases the cost of the block. This results in another desirable feature of the present invention. Since the blocks are manufactured in an overlapping configuration they form a compact and efficient package which is easy to handle and requires less space for shipping. The front surface of the block may be provided with a desired appearance or pattern by treating the surface as it is removed from the mold, just after it has been removed from the mold, or after curing. The surface appearance can be made to be smooth, corduroy, molded, fluted, ribbed, sand blasted, or fractured, as is known to one of skill in the art. Chamfers or other edge detail can be included in this molding process, as desired, or a block can be treated after curing to round the edges, by methods known to those of skill in the art. A fractured or split appearance is desirable because the surface then has the appearance of natural stone. Mechanical means can be used to treat the surface of a block after it has been cured and such is very effective in producing the appearance of natural stone. Such means are described in commonly assigned, co-pending application U.S. Application Publication No. 2003-0214069 (Ser. No. 10/150,484, filed May 17, 2002), hereby incorporated herein by reference. Though the blocks illustrated in the Figures may have any desired dimension, block 100, for example (as in FIGS. 3 to 8) typically has a thickness (i.e., the distance between surfaces 102 and 103) of about 8 inches (20.3 cm) and a length (i.e., the distance from corner 20a to corner 21a) of about 24 inches (60.1 cm). The length is determined by distance d1 of the mold box. For those blocks described above having a length of about 24 inches (60.1 cm), a depth (i.e., from the front surface to a back surface) of about 12 inches (30.5 cm), and a thickness of about 8 inches (20.3 cm), the weight is about 95 pounds. This translates to about 60 pounds per square foot of front face surface area. This is a convenient weight to use when positioning the blocks in a retaining wall and compares favorably to the weight of Prior Art blocks in terms of handling. Thus the blocks offer an advantage over the Prior Art blocks in terms of their higher front surface area per unit weight. The blocks of this invention are efficient to use in constructing walls because the relatively larger face size, compared to the face size of prior art blocks, results in about one third more area when building a wall. Although particular embodiments have been disclosed herein in detail, this has been done for purposes of illustration only, and is not intended to be limiting with respect to the scope of the claims. In particular, it is contemplated that various substitutions, alterations and modifications may be made to the invention without departing from the spirit and scope of the invention as defined by the claims. For instance, the choice of materials or variations in the shape or angles at which some of the surfaces intersect are believed to be a matter of routine for a person of ordinary skill in the art with knowledge of the embodiments disclosed herein. | <SOH> BACKGROUND OF THE INVENTION <EOH>Numerous methods and materials exist for the construction of retaining walls. Such methods include the use of natural stone, poured in place concrete, masonry, and landscape timbers or railroad ties. In recent years, segmental concrete retaining wall units which are dry stacked (i.e., built without the use of mortar) have become a widely accepted product for the construction of retaining walls. Such products have gained popularity because they are mass produced, and thus relatively inexpensive. They are structurally sound, easy and relatively inexpensive to install, and couple the durability of concrete with the attractiveness of various architectural finishes. It is desirable to build a wall from such blocks quickly and without the need for special skilled labor. The efficiency of building a wall can be measured by determining how fast the front face of a wall is constructed. Clearly, this depends on the size of the blocks used and ease of stacking the blocks. It is standard practice in the prior art to use similarly sized mold boxes to produce various styles of block. For example, a standard size box has a block molding area of about 18 inches by about 24 inches (about 45.7 cm by about 61 cm), and produces a block about 8 inches (20.3 cm) thick. FIG. 1A illustrates retaining wall block B 1 in mold box M. This block is symmetrical about a centrally located vertical plane of symmetry. Block B 1 has pin holes PH, pin receiving cavities PC, and two cores C 1 and C 2 . The sides generally converge from the front to the back of the block. Front face F is produced by the removal of waste portion W after the block has formed. This portion is split off to form a roughened surface. The block of FIG. 1A is manufactured one block at a time so that the yield per cycle is one square foot (1 sq ft or 929 sq cm) of front face. A typical weight for this block is about 110 lbs (50 kg). Other prior art blocks are shown in FIGS. 1B and 1C in mold box M. This block is similar to that described in WO 02/101157 (MacDonald et al.). This block also has similarities to block B 1 , as it is symmetrical about a centrally located vertical plane of symmetry. Block B 2 has pin holes PH, pin receiving cavities PC, and core C. Preferably, the blocks are formed so that front face F will have a roughened appearance. Block B 2 is made in a mold box two at one time. This provides a good use of mold space, producing about two square feet (1858 sq cm) of front face per manufacturing cycle. FIG. 1B illustrates that the blocks can be formed two at a time and separated at the back faces. In this case, the front surface of the block is textured by texturing elements T that contact the front surface as the block is removed from the mold box. FIG. 1C shows blocks that are molded together at front face F. The front faces of these blocks will be separated, or split apart after curing. The splitting of such blocks is used to form the desirable surface appearance. When manufactured in this manner, each block has a front face of about one square foot (1 sq ft or 929 sq cm). Thus, the yield per cycle is two square feet of front face. A typical weight for this block is about 85 lbs (38.6 kg). A third type of prior art block in its mold box M is shown in FIG. 1D . Block B 3 is a rectangular block, shown having two cores or cavities C. The long dimension of the block typically is used to form the face of a wall. Thus, this type of block produces a useful front surface about 24 inches long, rather than the 18 inch long surface of blocks B 1 and B 2 . The surface area (for the same thickness block, i.e., about 8 inches) is about 33% greater than the surface area of blocks B 1 or B 2 . However, this block weighs about 250 lbs (113.6 kg) and must be set in place using mechanized means. Accordingly, a need in the art remains for wall blocks that make the most use of a mold box's area while producing a block with a large front surface area. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention is a mold box and a method of making a wall block that maximizes the use of the mold box and produces wall blocks having a large surface area front face that are lightweight and easy to handle when constructing a wall. This results in faster construction of walls and a faster construction sequence, because for each block, the front face surface area is larger than blocks known in the art. The method of making the blocks makes efficient use of mold space and material, resulting in higher production yields and/or higher total daily production square footage. In one aspect, this invention is a mold box for making first and second wall blocks comprising first and second opposed end rails and first and second opposed side rails, the end rails and side rails together forming a mold cavity, the first and second end rails being spaced apart a distance d1, the first and second side rails being spaced apart a distance d2 which is less than distance d1; and a divider plate having a first end connected to the first end rail and a second end connected to the second end rail, the divider plate dividing the mold cavity into a first mold section for forming the first block and a second mold section for forming the second block. In another aspect, this invention is a mold box for making first and second wall blocks comprising first and second opposed end rails and first and second opposed side rails, the end rails and side rails together forming a mold cavity, the first and second end rails being spaced apart a distance d1, the first and second side rails being spaced apart a distance d2 which is less than distance d1; and a divider plate having a first end connected to the first end rail and a second end connected to the second end rail, the divider plate dividing the mold cavity into a first mold section for forming the first block and a second mold section for forming the second block, the first mold section being configured such that a front face of the first block is formed adjacent the first side rail, the second mold section being configured such that a front face of the second block is formed adjacent the second side rail. In another aspect, this invention is a mold box for making first and second wall blocks comprising first and second opposed end rails and first and second opposed side rails, the end rails and side rails together forming a mold cavity, the first and second end rails being spaced apart a distance d1, the first and second side rails being spaced apart a distance d2 which is less than distance d1; and a divider plate having a first end connected to the first end rail and a second end connected to the second end rail, the divider plate dividing the mold cavity into a first mold section for forming the first block and a second mold section for forming the second block, the first mold section being configured such that a front face of the first block is formed adjacent the first side rail, the second mold section being configured such that a front face of the second block is formed adjacent the second side rail, the divider plate being shaped in a non-planar configuration such that a maximum first block depth measured between the first side rail and the divider plate along a line generally perpendicular to the first side rail is greater than d2/2 and a maximum second block depth measured between the second side rail and the divider plate along a line generally perpendicular to the second side rail is greater than d2/2. In another aspect, this invention is a method of making wall blocks comprising providing a mold box having first and second opposed end rails and first and second opposed side rails, the end rails and side rails together forming a mold cavity, the first and second end rails being spaced apart a distance d1, the first and second side rails being spaced apart a distance d2 which is less than distance d1; dividing the mold cavity into a first mold section for forming a first block and a second mold section for forming a second block, the first mold section being configured such that a front face of the first block is formed adjacent the first side rail, the second mold section being configured such that a front face of the second block is formed adjacent the second side rail; filling the first and second mold sections with a desired block material; and removing the block material from the first mold section to form the first block and from the second mold section to form the second block, the first block having a maximum depth measured between the front face and a rear face along a line generally perpendicular to the front face which is greater than d2/2 and the second block having a maximum depth measured between the front face and a rear face along a line generally perpendicular to the front face which is greater than d2/2. In another aspect, this invention is a method of making wall blocks comprising providing a mold box having first and second opposed end rails and first and second opposed side rails, the end rails and side rails together forming a mold cavity, the first and second end rails being spaced apart a distance d1, the first and second side rails being spaced apart a distance d2 which is less than distance d1; dividing the mold cavity into a first mold section for forming a first block and a second mold section for forming a second block, the first mold section being configured such that a front face of the first block is formed adjacent the first side rail, the second mold section being configured such that a front face of the second block is formed adjacent the second side rail; filling the first and second mold sections with a desired block material; and removing the block material from the first mold section to form the first block and from the second mold section to form the second block, the front faces of the first and second blocks each having a length approximately equal to d1. In another aspect, this invention is a method of making wall blocks comprising providing a mold box having first and second opposed end rails and first and second opposed side rails, the end rails and side rails together forming a mold cavity, the first and second end rails being spaced apart a distance d1, the first and second side rails being spaced apart a distance d2 which is less than distance d1; connecting a divider plate between the first and second end rails to divide the mold cavity into a first mold section for forming a first block and a second mold section for forming a second block, the first mold section being configured such that a front face of the first block is formed adjacent the first side rail, the second mold section being configured such that a front face of the second block is formed adjacent the second side rail; filling the first and second mold sections with a desired block material; and removing the block material from the first mold section to form the first block and from the second mold section to form the second block. In another aspect, this invention is a method of making wall blocks comprising providing a mold box having first and second opposed end rails and first and second opposed side rails, the end rails and side rails together forming a mold cavity, the first and second end rails being spaced apart a distance d1, the first and second side rails being spaced apart a distance d2 which is less than distance d1; connecting a divider plate between the first and second end rails to divide the mold cavity into a first mold section for forming a first block and a second mold section for forming a second block, the first mold section being configured such that a front face of the first block is formed adjacent the first side rail, the second mold section being configured such that a front face of the second block is formed adjacent the second side rail, the divider plate being non-planar and having a first mold surface and a second mold surface, a rear face of the first block being formed adjacent the first mold surface and a rear face of the second block being formed adjacent the second mold surface, the divider plate being configured such that the rear faces of the first and second blocks overlap when they are formed in the mold cavity; filling the first and second mold sections with a desired block material; and removing the block material from the first mold section to form the first block and from the second mold section to form the second block. In another aspect, this invention is a wall block comprising a front portion including opposed top and bottom surfaces, opposed side surfaces and a front surface, the front surface having a length equal to the distance between the side surfaces and a height equal to the distance between the top and bottom surfaces. The at least one leg extends from the front portion in a direction opposite the front surface and has a rear surface, a distance between the front surface and rear surface comprising a maximum block depth. The at least one leg is positioned such that when a plurality of the blocks including first and second blocks are packaged for shipment the first and second blocks can be positioned on a common surface with their front surfaces oriented in opposite directions with the at least one leg of the first block overlapping the at least one leg of the second block so that the first and second blocks occupy an area on the common surface which is less than the length of the front surface times twice the block depth. In another aspect, the invention is a wall block comprising a front portion including opposed top and bottom surfaces, opposed side surfaces and a front surface, the front surface having a length equal to the distance between the side surfaces and a height equal to the distance between the top and bottom surfaces. The at least one leg extends from the front portion in a direction opposite the front surface and has a rear surface, the at least one leg being positioned such that when a wall is formed from multiple courses of the blocks which are offset from course to course by about one half the length of the front surface the legs in each course of blocks align vertically. | 20040109 | 20100824 | 20050127 | 76453.0 | 1 | SAFAVI, MICHAEL | MOLD BOX FOR MAKING FIRST AND SECOND WALL BLOCKS | UNDISCOUNTED | 1 | CONT-ACCEPTED | 2,004 |
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10,754,739 | ACCEPTED | Low cost surge protection | A motor drive for an electric machine includes a live line, a second line, and a ground line. A surge protector includes a first varistor and a gas discharge tube (GDT) that is non-conductive below a trigger voltage and that is conductive above the trigger voltage. The first varistor and the GDT are connected in series between one of the live line and the second line and the second line and the ground line. A second varistor is connected between the other of the live line and the second line and the second line and the ground line. When a voltage on the live line exceeds the trigger voltage, the first varistor, the second varistor and the GDT limit voltage output to the electric machine and deliver excess voltage to the ground line. | 1. A motor drive for an electric machine, comprising: a live line; a second line; a ground line; and a surge protector including: a first varistor; and a gas discharge tube (GDT) that is non-conductive below a trigger voltage and that is conductive above said trigger voltage, wherein said first varistor and said GDT are connected in series between one of said live line and said second line and said second line and said ground line. 2. The motor drive of claim 1 wherein said first varistor has a voltage threshold that is less than a hi-pot test voltage and said trigger voltage, wherein said hi-pot test voltage is less than said trigger voltage, and wherein said trigger voltage is less than a surge voltage. 3. The motor drive of claim 1 wherein said surge protector further comprises a second varistor connected between the other of said live line and said second line and said second line and said ground line. 4. The motor drive of claim 3 wherein when a voltage on said live line exceeds said trigger voltage, said first varistor, said second varistor and said GDT clamp excess voltage between said live line and said second line and clamp excess voltage between said second line and said ground line. 5. The motor drive of claim 1 wherein said surge protector further includes a fuse that is connected in series with said live line and that creates an open-circuit when current flowing through said fuse exceeds a current threshold of said fuse. 6. The motor drive of claim 1 further comprising a rectifier that communicates with said live line, said second line and said ground line and that converts an AC power input to a DC power output. 7. The motor drive of claim 6 wherein said rectifier is a doubler-type rectifier. 8. The motor drive of claim 1 wherein said second line is a neutral line. 9. The motor drive of claim 1 wherein said second line is a second live line. 10. The motor drive of claim 6 further comprising: a first capacitor that has one end that communicates with a first output of said rectifier and an opposite end that communicates with said second line; and a second capacitor that has one end that communicates with a second output of said rectifier and an opposite end that communicates with said second line. 11. The motor drive of claim 10 further comprising: a first resistor that is connected in parallel to said first capacitor; a second resistor that is connected in parallel to said second capacitor. 12. The motor drive of claim 3 wherein said first and second varistors are metal oxide varistors (MOVs). 13. A motor drive for an electric machine, comprising: a live line; a second line; a ground line; and a surge protector including: a first varistor; a gas discharge tube (GDT) that is non-conductive below a trigger voltage and that is conductive above said trigger voltage, wherein said first varistor and said GDT are connected in series between one of said live line and said second line and said second line and said ground line; and a second varistor connected between the other of said live line and said second line and said second line and said ground line. 14. The motor drive of claim 13 wherein said first and second varistors have a voltage threshold that is less than a hi-pot test voltage and said trigger voltage, wherein said hi-pot test voltage is less than said trigger voltage, and wherein said trigger voltage is less than a surge voltage. 15. The motor drive of claim 13 wherein when a voltage on said live line exceeds said trigger voltage, said first varistor, said second varistor and said GDT clamps excess voltage between said live line and said second line and clamps excess voltage between said second line and said ground line. 16. The motor drive of claim 13 wherein said surge protector further includes a fuse that is connected in series with said live line and that creates an open-circuit when current flowing through said fuse exceeds a current threshold of said fuse. 17. The motor drive of claim 13 further comprising a rectifier that communicates with said live line, said second line and said ground line and that converts an AC power input to a DC power output. 18. The motor drive of claim 17 wherein said rectifier is a doubler-type rectifier. 19. The motor drive of claim 18 further comprising: a first capacitor that has one end that communicates with a first output of said rectifier and an opposite end that communicates with said second line; and a second capacitor that has one end that communicates with a second output of said rectifier and an opposite end that communicates with said second line. 20. The motor drive of claim 19 further comprising: a first resistance having one end that is connected in parallel to said first capacitor; a second resistance that is connected in parallel to said second capacitor. 21. The motor drive of claim 13 wherein said first and second varistors are metal oxide varistors (MOVs). 22. The motor drive of claim 13 wherein said second line is a neutral line. 23. The motor drive of claim 13 wherein said second line is a second live line. 24. A method for insulation testing an electric machine with a surge protection circuit without using a jumper circuit to disconnect said surge protection circuit during said insulation testing, comprising: providing an electric machine having a live line, a ground line and a second line; connecting a first varistor and a gas discharge tube (GDT) in series between one of a live line and a second line and said second line and said ground line; and performing said insulating testing. 25. The method of claim 24 further comprising setting a trigger voltage of said GDT, wherein said GDT is conductive above said trigger voltage and non-conductive below said trigger voltage. 26. The method of claim 25 further comprising setting a voltage threshold of said first varistor less than a hi-pot test voltage and said trigger voltage, said hi-pot test voltage less than said trigger voltage, and said trigger voltage is less than a surge voltage. 27. The method of claim 26 wherein said surge protector further comprises a second varistor connected between the other of said live line and said second line and said second line and said ground line. 28. The method of claim 27 further comprising clamping excess voltage between said live line and said second line and between said second line and said ground line when a voltage on said live line exceeds said trigger voltage using said first varistor, said second varistor and said GDT. | FIELD OF THE INVENTION The present invention relates to appliance motor drives, and more particularly to an appliance motor drive incorporating low cost surge protection. BACKGROUND OF THE INVENTION Appliances, such as dishwashers, washing machines, clothes dryers, and the like are typically driven by electric machines. A motor drive provides power from a source, such as a household power outlet, to the electric machine. The household power outlet typically supplies A/C power at a line voltage (such as 115V) and a line frequency (such as 60 Hz). Line voltage transients, or surges, can occur due to lightning strikes and other sources. Voltage surges may reach up to 6000V. Residential electrical appliances are designed to withstand these power surges. Some motor drives incorporate surge protection circuits that limit damage due to power surges. One surge protection circuit includes a line to neutral metal oxide varistor (MOV) and a neutral to ground MOV in the motor drive circuitry. The MOV's clamp the surge voltages. Appliances typically undergo insulation testing, which requires 1200V to 1800V to be applied to the electric machine through the motor drive. This high voltage causes conduction of traditional MOV-type surge protectors that are incorporated in the motor drive which prevents satisfactory testing. As a result, a jumper circuit is used during insulation testing to disconnect the surge protection circuit. The requirement of connecting and disconnecting the jumper circuit adds additional cost and time to the manufacturing process. Another surge protection circuit employs spark gaps in the circuit board of the motor drive. The breakdown voltage of spark gaps, however, is adversely impacted by dirt and humidity variations. Spark gaps are further subject to carbon accumulation and metal displacement from electrodes into the spark gap area, which limits their useful life. SUMMARY OF THE INVENTION A motor drive for an electric machine according to the present invention includes a live line, a second line, and a ground line. A surge protector includes a first varistor and a gas discharge tube (GDT) that is non-conductive below a trigger voltage and that is conductive above the trigger voltage. The first varistor and the GDT are connected in series between one of the live line and the second line and the second line and the ground line. In other features, the first varistor has a voltage threshold that is less than a hi-pot test voltage and the trigger voltage. The hi-pot test voltage is less than the trigger voltage. The trigger voltage is less than a surge voltage. In yet other features, the surge protector further comprises a second varistor connected between the other of the live line and the second line and the second line and the ground line. When a voltage on the live line exceeds the trigger voltage, the first varistor, the second varistor and the GDT function to limit the voltages. In still other features, the surge protector further includes a fuse that is connected in series with the live line and that creates an open-circuit when current flowing through the fuse exceeds a current threshold of the fuse. In still other features, a rectifier communicates with the live line, the second line and the ground line and converts an AC power input to a DC power output. A first capacitor has one end that communicates with a first output of the rectifier and an opposite end that communicates with the second line. A second capacitor has one end that communicates with a second output of the rectifier and an opposite end that communicates with the second line. A first resistor is connected in parallel to the first capacitor. A second resistor is connected in parallel to the second capacitor. In still other features, the first and second varistors are metal oxide varistors (MOVs). Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: FIG. 1 illustrates an electric machine that receives power from a motor drive; and FIG. 2 is an electrical schematic of the motor drive according to the principles of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. For purposes of clarity, the same reference numbers will be used in the drawings to identify similar elements. Referring now to FIG. 1, an electric machine 10 is schematically illustrated. In one embodiment, the electric machine 10 is a direct-current (DC) or alternating-current (AC), fractional horsepower (Hp) electric machine. The electric machine 10 is powered by a voltage signal (AC or DC) and generates power under 1 Hp. While a fractional Hp electric machine is shown and described, other types of electric machines may be used. The voltage signal to the electric machine 10 is supplied by a motor drive 12. A motor drive connector 14 that is associated with the motor drive 12 is connected to an electric machine connector 16 that is associated with the electric machine 10. An alternating-current (AC) power source 18 provides an AC voltage signal to the motor drive 12 through a power input 20. The motor drive 12 converts the AC voltage signal to a DC voltage signal to power the electric machine 10, in the case of a DC electric machine. Referring now to FIG. 2, an electrical schematic of the motor drive 12 is illustrated. The motor drive 12 includes the power input 20 and a power output or voltage bus 22. The power input 20 includes a live line 24, a second line 26 and a ground line 28. In the case of a 115V application, the second line 26 is a neutral line. In the case of a 230V application, the second line 26 is a second live line. Power is supplied to the voltage bus 22 via the live and second lines 24 and 26. The ground line 28 is connected to a safety ground 30. A voltage rectifier 32 converts the AC voltage signal from the power input 20 to the DC voltage signal. In some applications, the voltage rectifier 32 can be a doubler-type voltage rectifier or a standard full wave-type voltage rectifier. The DC voltage signal is supplied to the voltage bus 22. The voltage bus 22 includes a voltage output terminal 34 and a common return terminal 36. The voltage bus 22 communicates with the motor drive connector 14 to supply the DC voltage signal to the electric machine 10 through the electric machine connector 16. Capacitors 38 and 40 store charge. Resistors 42, 44, 46 and 48 equalize stored charges in the capacitors 38 and 40. While four resistors are shown, additional or fewer resistors may be used. A motor case terminal 50 is connected to a motor case (not shown) of the electric machine 10 through the connectors 14 and 16. A capacitor 52 enables voltage from the motor case to bypass the voltage bus 22 to the common return 36. In this manner, electro-magnetic interference (EMI) from the motor case is limited. Resistors 54 and 56 allow the motor case to float while enabling a DC path to ground 30. In this manner, charge is not built up in the motor case over time. The motor drive 12 includes a surge protector 58 that prevents excessive voltage from damaging the components of the motor drive 12 and the electric machine 10. The surge protector 58 includes a fuse 60 in the live line 24 and a metal-oxide varistor (MOV) 62 that bridges the live and second lines 24 and 26. The surge protector 58 further includes MOV 64 and a gas-discharge tube (GDT) 66 that are connected in series and that bridge the second line and the ground line 26 and 28. The surge protector 58 enables insulation testing, discussed in further detail below, without modification to the motor drive 12, while protecting the motor drive 12 and electric machine 10 from voltage surges. The MOV's 62 and 64 limit surge voltages by clamping them as will be described. The MOV's 62 and 64 provide a variable resistance that is based on the voltage across each. Each MOV 62 and 64 includes a corresponding voltage threshold or break-over voltage. Exemplary break-over voltages for the MOV's 62 and 64 are between approximately 600V and 800V. When the voltage across the MOV is less than its break-over voltage, the MOV has a high resistance that limits current flow. When the voltage across the MOV is above its break-over voltage, the MOV has a relatively low resistance that limits the voltage. The GDT 66 also limits voltage. The GDT 66 includes an inert gas within a ceramic housing that is capped by electrodes (not shown). The GDT 66 has a trigger voltage, above which it becomes conductive. An exemplary trigger voltage is between 3000V and 3500V. For example, when the voltage across the GDT 66 is below the trigger voltage, the GDT 66 is non-conductive (i.e., no current flow therethrough). When the voltage across the GDT 66 is above the trigger voltage, the GDT 66 is conductive and current flows therethrough. Once the GDT 66 is triggered, it becomes highly conductive. This further limits the voltage and reduces the possibility of damage from the voltage surge. The fuse 60 also provides surge protection. When the current exceeds the rated current of the fuse, the fuse blows and creates an open-circuit. The open-circuit prevents power flow through the motor drive 12 and prevents operation of the electric machine 10. If a normal, sustained voltage appears on the second line 26, the series MOV 64 allows the normal voltage without clamping. When operating under a normal condition, the AC voltage signal from the power source 18 is supplied to the voltage rectifier 32 through the live and second lines 24 and 26. The voltage rectifier 32 converts the AC voltage signal to the DC voltage signal, which is supplied to the voltage bus 22. The DC signal from the voltage bus drives the electric machine 10 through the connectors 14 and 16. Prior to entering the marketplace, the motor drive 12 may undergo insulation testing or high potential (hi-pot) testing to insure component integrity. Hi-pot testing generally requires applying an AC voltage signal to the power input 20 at approximately twice the line voltage plus 1000V. The line voltage can be 115V, or other voltage levels. In applications including a doubler-type voltage rectifier, the line voltage is typically 115V. Therefore, during hi-pot testing, 1230V (2*115V+1000V) to as much as 1460V (2*230V+1000V) can be supplied through the motor drive 12. In one test, the hi-pot testing includes application of the amplified voltage through the motor drive 12 for a 60 second period. However, in hi-pot testing, the testing time can be reduced by increasing the applied voltage. More particularly, an increase of approximately 20% in the voltage reduces the testing time to approximately 1 second. Therefore, in the lightest case, 1230V is applied through the motor drive 12 (115V application using 60s test time). In the heaviest case, up to approximately 1800V is applied through the motor drive 12 (230V application using 1s test time). When hi-pot testing, the live and second lines 24 and 26 are interconnected by a jumper (not shown). An amplified AC voltage is applied between the combined live line 24 and second line 26 and ground 30. The amplified voltage ranges between approximately 1230V and 1800V depending on the application type and testing time, as discussed above. The amplified voltage signal is supplied to the voltage rectifier 32 through the combined live and second lines 24 and 26. Neither the MOV 62 nor the series MOV 64 and GDT 66 affect the application of the amplified voltage during hi-pot testing. Because the live and second lines 24 and 26 are combined, opposite ends of the MOV 62 are at the same voltage potential and there is no voltage drop across the MOV 62. Therefore, the break-over voltage of the MOV 62 is not reached. Although the break-over voltage of the MOV 64 would be achieved during hi-pot testing, the trigger voltage of the GDT 66 is not achieved. Therefore, the GDT 66 remains non-conductive and there is no path to ground 30. A voltage surge from the power source 18 induces operation of the motor drive 13 under a surge condition. A lightning strike or other event can induce a voltage surge up to approximately 6000V. Additionally, surges can occur in one of two modes, a common mode and a differential mode. In the common mode, the voltage surge is applied through the motor drive 12 via both the live and second lines 24 and 26 (i.e., live and second lines are combined). In the differential mode, the voltage surge is applied through the motor drive 12 via the live line 24, as would occur during normal operation. During a common mode surge, the MOV 64 and the GDT 66 limit the voltage through the motor drive 12 and divert the excess voltage to ground 30. More particularly, as the voltage surges, the voltage across the MOV 64 exceeds the break-over voltage and the voltage across the GDT 66 exceeds the trigger voltage. As a result, the GDT 66 is conductive and diverts the excess voltage to ground 30. During a differential mode surge, the MOV 62 limits the voltage to the motor drive 12, clamping the excess voltage as previously described. More particularly, as the voltage surges, the voltage across the MOV 62 achieves its break-over voltage. Although the present description and Figures illustrate the MOV 64 and the GDT 66 connected in series between the second line 26 and the ground line 28, it is anticipated that the MOV 64 and the GDT 66 can be connected in series between the live line 24 and the second line 26. With this configuration, the MOV 62 is connected across the second line 26 and the ground line 28. The surge protector 58 provides similar surge protection of the motor drive 12 in this alternative configuration. Those skilled in the art can now appreciate from the foregoing description that the broad teachings of the present invention can be implemented in a variety of forms. Therefore, while this invention has been described in connection with particular examples thereof, the true scope of the invention should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, the specification and the following claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>Appliances, such as dishwashers, washing machines, clothes dryers, and the like are typically driven by electric machines. A motor drive provides power from a source, such as a household power outlet, to the electric machine. The household power outlet typically supplies A/C power at a line voltage (such as 115V) and a line frequency (such as 60 Hz). Line voltage transients, or surges, can occur due to lightning strikes and other sources. Voltage surges may reach up to 6000V. Residential electrical appliances are designed to withstand these power surges. Some motor drives incorporate surge protection circuits that limit damage due to power surges. One surge protection circuit includes a line to neutral metal oxide varistor (MOV) and a neutral to ground MOV in the motor drive circuitry. The MOV's clamp the surge voltages. Appliances typically undergo insulation testing, which requires 1200V to 1800V to be applied to the electric machine through the motor drive. This high voltage causes conduction of traditional MOV-type surge protectors that are incorporated in the motor drive which prevents satisfactory testing. As a result, a jumper circuit is used during insulation testing to disconnect the surge protection circuit. The requirement of connecting and disconnecting the jumper circuit adds additional cost and time to the manufacturing process. Another surge protection circuit employs spark gaps in the circuit board of the motor drive. The breakdown voltage of spark gaps, however, is adversely impacted by dirt and humidity variations. Spark gaps are further subject to carbon accumulation and metal displacement from electrodes into the spark gap area, which limits their useful life. | <SOH> SUMMARY OF THE INVENTION <EOH>A motor drive for an electric machine according to the present invention includes a live line, a second line, and a ground line. A surge protector includes a first varistor and a gas discharge tube (GDT) that is non-conductive below a trigger voltage and that is conductive above the trigger voltage. The first varistor and the GDT are connected in series between one of the live line and the second line and the second line and the ground line. In other features, the first varistor has a voltage threshold that is less than a hi-pot test voltage and the trigger voltage. The hi-pot test voltage is less than the trigger voltage. The trigger voltage is less than a surge voltage. In yet other features, the surge protector further comprises a second varistor connected between the other of the live line and the second line and the second line and the ground line. When a voltage on the live line exceeds the trigger voltage, the first varistor, the second varistor and the GDT function to limit the voltages. In still other features, the surge protector further includes a fuse that is connected in series with the live line and that creates an open-circuit when current flowing through the fuse exceeds a current threshold of the fuse. In still other features, a rectifier communicates with the live line, the second line and the ground line and converts an AC power input to a DC power output. A first capacitor has one end that communicates with a first output of the rectifier and an opposite end that communicates with the second line. A second capacitor has one end that communicates with a second output of the rectifier and an opposite end that communicates with the second line. A first resistor is connected in parallel to the first capacitor. A second resistor is connected in parallel to the second capacitor. In still other features, the first and second varistors are metal oxide varistors (MOVs). Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. | 20040109 | 20071225 | 20050714 | 98362.0 | 1 | NGUYEN, DANNY | LOW COST SURGE PROTECTION | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,754,789 | ACCEPTED | Time-hopping systems and techniques for wireless communications | Systems and techniques are disclosed relating to wireless communications. The systems and techniques involve wireless communications wherein a process, module or communications terminal schedules communications over a frame having a plurality of time slots. The process, module or communications terminal may be used to assign information to be transmitted between two terminals to a block of the time slots within a frame, and reordering the time slot assignments within the frame using a permutation function, the permutation function being a function of frame count. | 1. A method of scheduling communications over a frame having a plurality of time slots, comprising: assigning information to be transmitted between two terminals to a block of the time slots within a frame; and reordering the time slot assignments within the frame using a permutation function, the permutation function being a function of frame count. 2. The method of claim 1 wherein the two terminals are in a first piconet, and wherein the method further comprises determining one or more time slots for a transmission between a terminal in a second piconet and a bridge terminal, the bridge terminal belonging to the first and second piconets, and using the determined one or more time slots as a constraint in the time slot assignments for the two terminals in the first piconet. 3. The method of claim 1 wherein the permutation function is further a function of an initial seed. 4. The method of claim 3 wherein the two terminals are in a piconet, and the initial seed is unique to the piconet. 5. The method of claim 3 further comprising providing the initial seed, the frame count, and the time slot assignments to each of the two terminals, and wherein the reordering of the assigned time slots is performed at each of the two terminals 6. The method of claim 3 wherein the two terminals are in a first piconet, and the initial seed is unique to the first piconet, the method further comprising providing the initial seed and the frame count for the first piconet to a terminal in a second piconet. 7. The method of claim 3 wherein the two terminals are in a first piconet, and the initial seed is unique to the first piconet, the method further comprising receiving a different initial seed and frame count from a terminal in a second piconet. 8. The method of claim 7 further comprising receiving time slot assignments from the terminal in the second piconet for information to be transmitted between the terminal in the second piconet and a bridge terminal, the bridge terminal belonging to both the first and second piconets. 9. The method of claim 8 further comprising reordering the received time slot assignments for the transmission between the terminal in the second piconet and the bridge terminal using the permutation function for the second piconet, demapping the reordered time slots for the transmission between the terminal in the second piconet and the bridge terminal using the permutation function for the first piconet, and using the demapped reordered time slots as a constraint in the block of time slot assignments for the information to be transmitted between the two terminal pairs. 10. The method of claim 1 further comprising identifying additional information to be transmitted between two different terminals, and assigning the additional information to at least a portion of the block of time slot assignments for the information. 11. The method of claim 10 further comprising assigning a first spreading code to the information, and a second spreading code to the additional information. 12. A communications terminal, comprising: a transceiver configured to receive a block of time slot assignments within a frame to communicate with a remote terminal; and a controller configured to reorder the time slot assignments within the frame using a permutation function, the permutation function being a function of frame count. 13. The communications terminal of claim 12 wherein the permutation function is further a function of an initial seed. 14. The communications terminal of claim 13 wherein the transceiver is further configured to receive the initial seed, the frame count, and the time slot assignments from a master terminal. 15. The communications terminal of claim 14 wherein the initial seed uniquely identifies the master terminal. 16. The communications terminal of claim 12 wherein the transceiver is further configured to communicate with the remote terminal during the reordered time slot assignments. 17. The communications terminal of claim 16 further comprising a processor configured to perform spread-spectrum processing on the communications. 18. A communications terminal configured to operate in a first piconet, comprising: a transceiver configured to receive a block of time slot assignments within a frame for a transmission between a bridge terminal and a terminal in a second piconet, the bridge terminal belonging to the first and second piconets; and a scheduler configured to reorder the time slot assignments within the frame using a permutation function for the second piconet, demap the reordered time slots within the frame using a permutation function for the first piconet, and use the demapped time slots as a constraint in assigning a block of time slots within the frame for a transmission between two terminals in the first piconet, the permutation for the first piconet being different from the permutation function for the second piconet. 19. The communications terminal of claim 18 wherein the transceiver is further configured to transmit the block of time slot assignments for the transmission between the two terminals to each of the two terminals. 20. The communications terminal of claim 18 wherein the permutation function for the first piconet is a function of an initial seed and frame count relating to the first piconet and the permutation function for the second piconet is related to an initial seed and frame count relating to the second piconet. 21. The communications terminal of claim 20 wherein the initial seed for the first piconet uniquely identifies the communication terminal. 22. The communications terminal of claim 20 wherein the transceiver is further configured to receive the initial seed and the frame count for the second piconet, and provide the received initial seed and the frame count for the second piconet to the scheduler. 23. The communications terminal of claim 18 wherein the scheduler is further configured to assign a spreading code to the transmission between the two terminals in the first piconet, and wherein the transceiver is further configured to transmit the spreading code to each of the two terminals in the first piconet. 24. A communications terminal, comprising: means for receiving a block of time slot assignments within a frame to communicate with a remote terminal; and means for reordering the time slot assignments within the frame using a permutation function, the permutation function being a function of frame count. | BACKGROUND 1. Field The present disclosure relates generally to wireless communications, and more specifically, to various time-hopping systems and techniques for wireless communications. 2. Background In conventional wireless communications, an access network is generally employed to support communications for a number of mobile devices. These access networks are typically implemented with multiple fixed site base stations dispersed throughout a geographic region. The geographic region is generally subdivided into smaller regions known as cells. Each base station may be configured to serve all mobile devices in its respective cell. As a result, the access network may not be easily reconfigured to account for varying traffic demands across different cellular regions. In contrast to the conventional access network, ad-hoc networks are dynamic. An ad-hoc network may be formed when a number of wireless communication devices, often referred to as terminals, decide to join together to form a network. Since terminals in ad-hoc networks operate as both hosts and routers, the network may be easily reconfigured to meet existing traffic demands in a more efficient fashion. Moreover, ad-hoc networks do not require the infrastructure required by conventional access networks, making ad-hoc networks an attractive choice for the future. A completely ad-hoc network consisting of peer-to-peer connections generally result in very inefficient communications. To improve efficiency, the terminals may organize themselves into a collection of piconets. A “piconet” is a group of terminals in close proximity to one another. The piconet may have a master terminal that schedules access to the communications medium for the terminals in its piconet. Numerous multiple access techniques exist to support communications in an ad-hoc network. A Frequency Division Multiple Access (FDMA) scheme, by way of example, is a very common technique. FDMA typically involves allocating distinct portions of the total bandwidth to individual communications between two terminals in the piconet. While this scheme may be effective for uninterrupted communications, better utilization of the total bandwidth may be achieved when such constant, uninterrupted communication is not required. Other multiple access schemes include Time Division Multiple Access (TDMA). These TDMA schemes may be particularly effective in allocating limited bandwidth among a number of terminals which do not require uninterrupted communications. TDMA schemes typically dedicate the entire bandwidth to each communication channel between two terminals at designated time intervals. Code Division Multiple Access (CDMA) techniques may be used in conjunction with TDMA to support multiple communications during each time interval. This may be achieved by transmitting each communication or signal in a designated time interval with a different code that modulates a carrier, and thereby, spreads the signal. The transmitted signals may be separated in the receiver terminal by a demodulator that uses a corresponding code to de-spread the desired signal. The undesired signals, whose codes do not match, are not de-spread and contribute only to noise. In TDMA systems that use spread-spectrum communications, each master terminal may schedule transmissions within its own piconet in a way that does not cause excessive mutual interference. However, it may be more difficult to manage interference from other piconets, or “inter-piconet interference”. Inter-piconet interference management generally involves the coordination of transmission schedules across multiple piconets. While this approach may be workable between a handful of master terminals, it may be problematic in larger networks due to scheduling delays and excessive overhead. Accordingly, a more robust and efficient scheduling algorithm is needed which addresses the problems of inter-piconet interference. SUMMARY In one aspect of the present invention, a method of scheduling communications over a frame having a plurality of time slots includes assigning information to be transmitted between two terminals to a block of the time slots within a frame, and reordering the time slot assignments within the frame using a permutation function, the permutation function being a function of frame count. In another aspect of the present invention, a communications terminal includes a transceiver configured to receive a block of time slot assignments within a frame to communicate with a remote terminal, and a controller configured to reorder the time slot assignments within the frame using a permutation function, the permutation function being a function of frame count. In yet another aspect of the present invention, a communications terminal configured to operate in a first piconet includes a transceiver configured to receive a block of time slot assignments within a frame for a transmission between a bridge terminal and a terminal in a second piconet, the bridge terminal belonging to the first and second piconets, and a scheduler configured to reorder the time slot assignments within the frame using a permutation function for the second piconet, demap the reordered time slots within the frame using a permutation function for the first piconet, and use the demapped time slots as a constraint in assigning a block of time slots within the frame for a transmission between two terminals in the first piconet, the permutation for the first piconet being different from the permutation function for the second piconet. In a further aspect of the present invention, a communications terminal includes means for receiving a block of time slot assignments within a frame to communicate with a remote terminal, and means for reordering the time slot assignments within the frame using a permutation function, the permutation function being a function of frame count. It is understood that other embodiments of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein various embodiments of the invention are shown and described by way of illustration. As will be realized, the invention is capable of other and different embodiments and its several details are capable of modification in various other respects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive. BRIEF DESCRIPTION OF THE DRAWINGS Aspects of the present invention are illustrated by way of example, and not by way of limitation, in the accompanying drawings, wherein: FIG. 1 is a conceptual diagram illustrating an example of a piconet; FIG. 2 is a conceptual diagram illustrating an example of two piconets forming a piconet cluster; FIG. 3 is a conceptual diagram illustrating an example of a piconet having a peer-to-peer connection with an isolated terminal; FIG. 4 is a conceptual diagram illustrating an example of two adjacent piconets; FIG. 5 is a conceptual diagram illustrating an example of a Medium Access Control (MAC) frame for controlling intra-piconet communications; FIG. 6 is a functional block diagram illustrating an example of a terminal capable of operating within a piconet; FIG. 7 is a functional block diagram illustrating an example of a baseband processor for a terminal; FIG. 8 is a conceptual diagram illustrating an example of a MAC before and after time slot randomization; FIG. 9 is a conceptual diagram illustrating another example of a MAC before and after time slot randomization; FIG. 10 is a conceptual diagram illustrating yet another example of a MAC before and after time slot randomization. DETAILED DESCRIPTION The detailed description set forth below in connection with the appended drawings is intended as a description of various embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. Each embodiment described in this disclosure is provided merely as an example or illustration of the present invention, and should not necessarily be construed as preferred or advantageous over other embodiments. The detailed description includes specific details for the purpose of providing a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the present invention. Acronyms and other descriptive terminology may be used merely for convenience and clarity and are not intended to limit the scope of the invention. In the following detailed description, various aspects of the present invention may be described in the context of an Ultra Wide Band (UWB) wireless communications system. While these inventive aspects may be well suited for use with this application, those skilled in the art will readily appreciate that these inventive aspects are likewise applicable for use in various other communication environments. Accordingly, any reference to a UWB communications system is intended only to illustrate the inventive aspects, with the understanding that such inventive aspects have a wide range of applications. FIG. 1 illustrates an example of a network topology for a piconet in a wireless communications system. A piconet 102 is shown with a master terminal 104 supporting communications between several member terminals 106a-106h. The master terminal 104 may be able to communicate with each of the member terminals 106 in the piconet. The member terminals 106 may also be able to directly communicate with one another under control of the master terminal 104. As to be explained in greater detail below, each member terminal 106 in the piconet 102 may also be able to directly communicate with terminals outside the piconet. The master terminal 104 may communicate with the member terminals 106 using a multiple access scheme, such as TDMA, FDMA, CDMA, or another multiple access scheme. To illustrate the various aspects of the present invention, the wireless communications system shown in FIG. 1 will be described in the context of a hybrid multiple access scheme employing both TDMA and CDMA technologies. Those skilled in the art will readily understand that the present invention is in no way limited to such multiple access schemes. A piconet may be formed in a variety of ways. By way of example, when a terminal initially powers up, it may search for pilot signals from various piconet master terminals. The pilot signal broadcast from each piconet master terminal may be an unmodulated spread-spectrum signal, or another type of reference signal. In spread-spectrum communications, a psuedo-random noise (PN) code unique to each piconet master terminal may be used to spread the pilot signal. Using a correlation process, the terminal may search through all possible PN codes to locate a pilot signal from a master terminal, such as the pilot signal broadcast from the master terminal 104 in FIG. 1. The pilot signal may be used by the member terminal 106 to synchronize to the master terminal 104. The acquisition of a spread spectrum pilot signal is well known in the art. The master terminal 104 may be used to manage high data rate communications. This may be achieved by allowing only those terminals that can support a minimum or threshold data rate with the master terminal 104 to join the piconet 102. In UWB communication systems, for example, a data rate of 1.2288 Mbps may be supported at a distance of 30-100 meters depending on the propagation conditions. In these systems, the master terminal 104 may be configured to organize the piconet 102 with member terminals 106 that can support a data rate of at least 1.2288 Mbps. If higher data rates are desired, the range may be further restricted. By way of example, data rates of 100 Mbps may be achieved in UWB systems at a range of 10 meters. The member terminal 106 may be configured to determine whether it can satisfy the minimum data rate requirements of the piconet by measuring the link quality using the pilot signal broadcast from the master terminal 104. As discussed in greater detail above, a terminal may identify a pilot signal through a correlation process. The link quality may then be measured by computing the carrier-to-interference (C/I) ratio from the pilot signal by means well known in the art. Based on the C/I ratio computation, the member terminal 106 may then determine whether the minimum or threshold data rate may be supported by means also well known in the art. If the member terminal 106 determines that the minimum or threshold data rate may be supported, it may attempt to join the piconet 102 by registering with the master terminal 104. A member terminal that is able to communicate at the minimum or threshold data rate with two (or more) master terminals becomes an “intra-cluster bridge terminal” between the two piconets, and the two piconets become members of the same cluster. FIG. 2 is an example of a network topology illustrating a cluster 202 formed by two piconets 102 and 204. The first piconet 102 of the cluster 202 is the same piconet described in connection with FIG. 1 with its master terminal 104 supporting several member terminals 106. The second piconet 204 of the cluster 202 includes a master terminal 206 also supporting several member terminals 208. The member terminal 106a is a member of both the first and second piconets 102 and 204, and is therefore an intra-cluster bridge terminal. If there is more than one intra-cluster bridge between two piconets, one of them is chosen to be the primary intra-cluster bridge and the others are secondary bridges. Communications between the two piconets 102 and 204 may be routed through the primary intra-cluster bridge terminal. In some instances, a terminal may be unable to find a pilot signal of sufficient signal strength to support the minimum or threshold data rate. This may result from any number of reasons. By way of example, the terminal may be too far from the master terminal. Alternatively, the propagation environment may be insufficient to support the requisite data rate. In either case, the terminal may be unable to join an existing piconet, and therefore, may begin operating as an isolated terminal by transmitting its own pilot signal. FIG. 3 illustrates an example of a network topology with a wireless terminal 302 that is unable to join the piconet 102 of FIG. 1. The master terminal 104 may designate a number of member terminals 106 as “piconet edge terminals”, such as the member terminal 106a. The designation of piconet edge terminals may be based on feedback from the various member terminals 106. The feedback may be used to provide a rough indication of those member terminals located at the edge of the piconet 102. The piconet edge terminal 106a may be assigned the task of searching for pilot signals from isolated terminals. When a piconet edge terminal 106a detects a pilot signal from an isolated terminal that cannot support the minimum required data rate, such as the isolated terminal 302 shown in FIG. 3, then the piconet edge terminal 106a may establish a peer-to-peer connection with the isolated terminal 302. The piconet edge terminal 106a becomes an “inter-piconet bridge terminal” to support communications between the isolated terminal 302 and a member terminal 106 in the piconet 102. The isolated terminal 302 may become the master terminal for a new piconet. Other terminals that are able to receive the pilot signal broadcast from the isolated terminal 302 with sufficient strength may attempt to acquire that pilot signal and join the piconet of this isolated terminal. FIG. 4 illustrates an example of a network topology of this kind. The first piconet 102 is the same piconet described in connection with FIG. 1 with its master terminal 104 supporting several member terminals 106. The isolated terminal 302 described in connection with FIG. 3 has become the master terminal for a second piconet 402. The master terminal 302 in the second piconet 402 may be used to support multiple member terminals 406. Using feedback from the various member terminals 406, the master terminal 302 in the second piconet 402 may designate one or more member terminals 406 as piconet edge terminals, such as the member terminal 406a. As described in greater detail above, the master terminal 104 in the first piconet 102 may also designate one or more member terminals 106 as piconet edge terminals, such as the member terminal 106a. Each piconet edge terminal may search for pilot signals from isolated terminals and master terminals of adjacent piconets unable to support the minimum required data rate. By way of example, when the piconet edge terminal 106a from the first piconet 102 detects the pilot signal broadcast from the master terminal 302 in the second piconet 402, it may establish a connection with that master terminal 302. The master terminal 302 may maintain that connection, or alternatively, assign a piconet edge terminal 406a in the second piconet 402 to maintain the connection. The piconet edge terminals 106a and 406a may be referred to as “inter-piconet bridge terminals”. Communications between a terminal in the first piconet 102 and a terminal in the second piconet 402 may be supported through the inter-piconet bridge terminals 106a and 406a. The master terminal 104 may use a periodic frame structure to coordinate communications within the piconet, or “intra-piconet communications”. This frame is typically referred to in the art as a Medium Access Control (MAC) frame because it is used to provide access to the communications medium for various terminals. The frame may be any duration depending on the particular application and overall design constraints. For the purpose of discussion, a frame duration of 5 ms will be used. A 5 ms frame is reasonable to accommodate a high chip rate of 650 Mcps and a desire to support data rates down to 19.2 kbps. An example of a MAC frame structure is shown in FIG. 5 with n number of frames 502. Each frame may be divided into 160 or another number of time slots 504. The slot duration may be 31.25 μs, which corresponds 20,312.5 chips at 650 Mcps. The frame may dedicate some of its slots for overhead. By way of example, the first slot 506 in the frame 502 may be used to broadcast the spread-spectrum pilot signal to all the member terminals. The pilot signal may occupy the entire slot 506, or alternatively, be time shared with a control channel as shown in FIG. 5. The control channel occupying the end of the first slot 506 may be a spread-spectrum signal broadcast to all the member terminals at the same power level as the pilot signal. The master terminal may use this control channel to define the composition of the MAC frame. The master terminal may be responsible for scheduling intra-piconet communications. This may be accomplished through the use of one or more additional spread-spectrum control channels which occupy various time slots within the frame, such as time slots 508 and 510 in FIG. 5. These additional control channels may be broadcast by the master terminal to all the member terminals and include various scheduling information. The scheduling information may include time slot assignments for communications between terminals within the piconet. As shown in FIG. 5, these time slots may be selected from the data slots portion 512 of the frame 502. Additional information, such as the power level and data rate for each communication between terminals, may also be included. The master terminal may also assign multiple terminal pairs to any given time slot using a CDMA scheme. In this case, the scheduling information may also assign the spreading codes to be used for the individual communications between terminals. FIG. 6 is a conceptual block diagram illustrating one possible configuration of a terminal. As those skilled in the art will appreciate, the precise configuration of the terminal may vary depending on the specific application and the overall design constraints. For the purposes of clarity and completeness, the various inventive concepts will be described in the context of a UWB terminal with spread-spectrum capability, however, such inventive concepts are likewise suitable for use in various other communication devices. Accordingly any reference to a spread-spectrum UWB terminal is intended only to illustrate the various aspects of the invention, with the understanding that such aspects have a wide range of applications. The terminal may be implemented with a front end transceiver 602 coupled to an antenna 604. A baseband processor 606 may be coupled to the transceiver 602. The baseband processor 606 may be implemented with a software based architecture, or another type of architecture. The software based architecture may configured with a microprocessor (not shown) that serves as a platform to run software programs that, among other things, provide executive control and overall system management functions that allow the terminal to operate either as a master or member terminal in a piconet. The baseband processor 606 may also include a digital signal processor (DSP) (not shown) with an embedded communications software layer which runs application specific algorithms to reduce the processing demands on the microprocessor. The DSP may be used to provide various signal processing functions such as pilot signal acquisition, time synchronization, frequency tracking, spread-spectrum processing, modulation and demodulation functions, and forward error correction. The terminal may also include various user interfaces 608 coupled to the baseband processor 606. The user interfaces may include, by way of example, a keypad, mouse, touch screen, display, ringer, vibrator, audio speaker, microphone, camera and/or the like. FIG. 7 is a conceptual block diagram illustrating an example of a baseband processor. The baseband processor 606 is shown with the transceiver 602. The transceiver 602 may include a receiver 702. The receiver 702 provides detection of desired signals in the presence of noise and interference. The receiver 702 may be used to extract the desired signals and amplify them to a level where information contained in the received signal can be processed by the baseband processor 606. The transceiver 602 may also include a transmitter 704. The transmitter 704 may be used to modulate information from the baseband processor 606 onto a carrier frequency. The modulated carrier may be upconverted to an RF frequency and amplified to a sufficient power level for radiation into free space through the antenna 604. The baseband processor 606 may be responsible for configuring the terminal as a master or member terminal of the piconet depending on the results of the pilot signal acquisition process. When the baseband processor 606 configures the terminal as a member terminal of the piconet, a signal processor 706 on the receiving end may be used to extract scheduling information broadcast by the piconet master terminal over one or more control channels. The signal processor 706 may use spread-spectrum processing, in conjunction with digital demodulation and forward error correction techniques, to extract the pertinent scheduling information from the control channel and provide it to a controller 708 for processing. The controller 708 may use the scheduling information to determine the time slots for the various transmissions to and from the member terminal, as well as the power level and data rate for each. In the receive mode, the controller 708 may be used to provide data rate and spreading information to the signal processor 706 on the receiving end for the scheduled transmissions to the member terminal. Using this information, the signal processor 706 may recover information embedded in the transmissions from other terminals at the appropriate times and provide the recovered information to the various user interfaces. A signal processor 710 on the transmitting end may be used to spread information destined for various other terminals. The information may be originated from the various user interfaces 608 and stored in a buffer 712 until the scheduled transmission. At the scheduled time, the controller 708 may be used to release the information from the buffer 712 to the signal processor 710 for spread-spectrum, processing. The signal processor 710 may also employ digital modulation and forward error correction techniques. The data rate, spreading code and power level of the transmission may be programmed into the signal processor 710 by the controller 708. Alternatively, the transmission power level may be programmed by the controller 708 at the transmitter 704 in the transceiver 602. When the baseband processor 606 configures the terminal as the master terminal of the piconet, it may enable a scheduler 714. In the software based implementation of the baseband processor 606, the scheduler 706 may be a software program running on the microprocessor. However, as those skilled in the art will readily appreciate, the scheduler 714 is not limited to this embodiment, and may be implemented by other means known in the art, including a hardware configuration, firmware configuration, software configuration, or combination thereof, which is capable of performing the various functions described herein. The scheduler 714 may be used to generate scheduling information to support intra-piconet communications. The scheduling information may be derived based on any number of considerations and/or in accordance with any known scheduling algorithm. By way of example, scheduling information may be made based on a priority system, where voice communications are given priority over high latency communications. The scheduler 714 may also give priority to high data rate transmissions in an effort to maximize throughput. Further increases in throughput may be achieved by scheduling parallel transmissions using spread-spectrum techniques. By carefully selecting the terminal pairs that will engage in parallel communications, intra-piconet interference may be managed. A fairness criteria that considers the amount of data to be transferred between terminal pairs and the delay already experienced by such terminal pairs may also be considered. Other factors may be considered and are within the scope of the present invention. Those skilled in the art will be readily able to adapt existing scheduling algorithms to any particular piconet application. Inter-piconet interference may be managed through the use of time hopping techniques. “Time hopping” refers to a process whereby a communication between two terminal pairs in a piconet are assigned a block of time slots in the MAC frame to handle the call, and then “reordered” or “randomized” before each transmission. The “reordering” or “randomizing” of the time slots in the MAC frame may be referred to herein as a “permutation.” Each MAC frame may have a different permutation which follows a pseudo-random permutation sequence. In at least one embodiment of the piconet, a block assignment for a call between two member terminals may be made by the scheduler 714 in the master terminal and transmitted to the two member terminals during call set-up. The controller 708 in each of the two member terminals may then reorder or randomize the time slot assignments every frame using the pseudo-random permutation sequence. More specifically, the controller 708 may use a permutation function (g) to compute a permutation for each MAC frame. The permutation function (g) may be a function of two input parameters, namely, an initial seed unique to the piconet and the frame count. The initial seed may be, by way of example, the identifier (ID) of the master terminal to which the member terminal is slaved. The master terminal ID is typically referred to as a MAC ID. The initial seed and the frame count may be maintained at the master terminal and provided to the various member terminals during call set-up. A permutation (p) of size n, where n is the number of time slots in a MAC frame, may be represented by the following relationship: p=g(initial seed, frame count); and p(i)=j, i,j=1 . . . n The permutation function (g) is known by all terminals in the network. When a terminal joins a piconet, it obtains the initial seed and the current frame count from the master terminal of that piconet during the registration process. With this approach, the data related to the permutation function needs to be sent from the master terminal only once during the registration process rather than every frame. In the event that a connection is set up between two terminals in a different piconets, then the permutation function (g) between the two terminals should be the synchronized. This may be accomplished in a variety of ways. Referring to FIG. 2, by way of example, if a terminal 106 in the first piconet 102 initiates a call with a terminal 208 in the second pioconet 204, then the initial seed and the current frame count of the first piconet 102 may be provided from the terminal 106 to the terminal 208 during call-set-up. This information allows the terminal 208 in the second piconet 204 to generate the same permutation that the terminal 106 in the first piconet 102 uses in every MAC frame. An example of a permutation for a single MAC frame will be described in connection with FIGS. 1, 7 and 8. A MAC frame before slot randomization is shown in FIG. 8A. The scheduler may use this MAC frame to assign blocks of time slots to intra-piconet communications in accordance with any of the scheduling considerations discussed earlier. In the example shown, a first transmission from the member terminal 106f to the member terminal 106e has been assigned to data slots 1-8. Simultaneously with the first transmission, is a transmission from the member terminal 106g to the member terminal 106b assigned to data slots 1-5, and a transmission from the master terminal 104 to the member terminal 106b assigned to data slots 6-8. These data slots are shown as shaded regions in FIGS. 8A and 8B. Later transmissions from the member terminal 106e to the member terminal 106c are assigned to data slots 9-15 and from the member terminal 106b to the member terminal 106g are assigned to data slots 9-12. These time slots are shown with slanted lining. The signal processor 710 on the transmitting end may be used to spread the block assignments before being provided to the transceiver 602 for broadcast to the various member terminals during call set-up. For communications involving the master terminal, the pertinent block assignments may be routed from the scheduler 714 to the controller 708, either directly or through the signal processor 710. The controller 708 in the appropriate terminals may be used to “reordered” or “randomized” the assigned time slots in accordance with the permutation function (g) before transmission. FIG. 8B is an example of the single MAC frame permutation. One can readily see from FIGS. 8A and 8B, that data slot 1 has been mapped to data slot 7, data slot 2 to data slot 10, data slot 3 to data slot 18, and so on. By mapping the data slots of the MAC frame for each piconet with a permutation that changes every frame in a different fashion for each piconet, an interference averaging effect is seen by each piconet. The scheduler may periodically set aside a fraction of the time for peer-to-peer communications. During this time, the inter-piconet bridge terminals may transmit to an isolated terminal or a distant piconet. Transmissions to a distant piconet may be either to its master terminal or its inter-piconet bridge terminal. These transmissions may require high transmit power, and in some instances can only be sustained at low data rates. In the event that high power transmissions are needed to communicate, the scheduler may decide not to assign any intra-piconet communications to the time slots supporting peer-to-peer communications. FIG. 9A shows a MAC frame permutation with a transmission from the inter-piconet bridge terminal 106a to the isolated terminal 302 of FIG. 3 assigned to data slots 16-18, shown with vertical lining. The data slots may be randomized by the controller in accordance with the permutation function as shown in FIG. 9B. Note that the scheduler in the master terminal has not assigned any other intra-piconet communications to the time slots assigned to the inter-piconet bridge terminal 106a to transmit to the isolated terminal 302. Returning to FIG. 2, the member terminal 106a is shown as an intra-cluster bridge terminal between the two piconets 102 and 204 forming the piconet cluster 202. In some embodiments, the intra-cluster bridge terminal 106a may be configured to receive the pilot signal and the control channels from both the master terminals 104 and 406 simultaneously. In other embodiments, the intra-cluster bridge terminal 106a may only be able to receive transmissions from one master terminal at a time. The later approach reduces receiver complexity at the intra-cluster bridge terminal 106a, and therefore, may be desirable in some applications. If the intra-cluster bridge terminal 106a can only receive transmissions from one master terminal at a time, then it may signal to one of the master terminals to adjust its MAC frame start time. Thus, multiple piconets in a cluster may have synchronized MAC frames which are offset in time. Different permutation functions among piconets of a cluster may present certain challenges to implementing of an efficient communications environment. By way of example, an “inter-piconet communication” from the intra-cluster bridge terminal 106a to a member terminal 208 in the second piconet 204 may be assigned by the master terminal 104 in the first piconet 102 to a block of time slots. However, since the two piconets use different permutation functions, communications within the second piconet 404 may interfere with the reception of the signal at the member terminal 408. Several approaches may be used to reduce or minimize this type of interference. By way of example, the intra-cluster bridge terminal 106a may use a high spreading factor and a low data rate so that the signal can be decoded at the member terminal 208 even in the presence of other communications within the second piconet 204. Alternatively, the two piconets may coordinate their respective intra-piconet communications to avoid this type of interference. An example of coordinating intra-piconet communications will be illustrated with the two piconet cluster shown in FIG. 2. Those skilled in the art will be readily able to extend the concepts disclosed herein to any number of piconets within a cluster. Referring to FIGS. 2 and 7, each master terminal 104 and 206 may provide to the other its initial seed and current frame count over one or more control channels in the MAC frame. This may be done through the intra-cluster bridge terminal 106a which communicates with both master terminals 104 and 206. More specifically, the scheduler 714 in each of the master terminals may provide its initial seed and current frame count to the baseband processor 606 for spread spectrum processing and transmit the sequence via the transceiver 602 to the intra-cluster bridge terminal 106a over one or more control channels. The intra-cluster bridge terminal 106a may forward the information received from each master terminal 104 and 206 to the other master terminal in much the same way. The scheduler 714 in the master terminal 104 for the first piconet 102 may then assign a block of time slots to communicate with the intra-cluster bridge terminal 106a. During call set-up, a number of time slots may be assigned to support transmissions from the master terminal 104 to the intra-cluster bridge terminal 106a, and a number of time slots may be assigned to support transmissions in the reverse direction. These time slot assignments may be provided to the baseband processor 606 for spread spectrum processing before being transmitted, via the transceiver 602, to the intra-cluster bridge terminal 106a over one or more control channels. The intra-cluster bridge terminal 106a may randomize the time slot assignments using the permutation function with the initial seed and the current frame count maintained by the master terminal 104 for the first piconet 102 to obtain the scheduled time slots for the communication. These scheduled time slots may then be forwarded from the intra-cluster bridge terminal 106a to the master terminal 206 in the second piconet 204 in the same manner, and become constraints in the time slot assignments generated by the master terminal 206. Similarly, the scheduled time slots resulting from the block assignment by the master terminal 206 in the second piconet 202 to support communications with the intra-cluster bridge terminal 106a becomes a constraint in the time slot assignments generated by the master terminal 104 in the first piconet 102. The constraints in the time slot assignments will be further illustrated with reference to FIGS. 2 and 10. A MAC frame for the first piconet 102 before slot randomization is shown in FIG. 10A, and the same MAC frame after slot randomization is shown in FIG. 10B. The time slots that have been scheduled for the master terminal 206 in the second piconet 404 to communicate with the intra-cluster bridge 106a are marked RESERVED in FIG. 10B. These are the scheduled time slots that result from applying the permutation function for the second piconet 204 to the block of time slots originally assigned by the master terminal 206. These RESERVED time slots in FIG. 10B may then be demapped using the permutation function for the first piconet 102 to the RESERVED time slots shown in FIG. 10A. These time slots are not available for scheduling intra-piconet communications in the first piconet 102. The concept of coordinating inter-piconet communications between the two master terminals 104 and 206 may be extended to other terminals in the piconet cluster. Whenever a connection is to be set up between two terminals in different piconets, the master terminals of those piconets can mark out the assigned time slots as unavailable during call set-up. In this way, inter-piconet communications can be made with reduced interference. The various illustrative logical blocks, modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. The methods or algorithms described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. A storage medium may be coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in the terminal, or elsewhere. In the alternative, the processor and the storage medium may reside as discrete components in the terminal, or elsewhere. The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. | <SOH> BACKGROUND <EOH>1. Field The present disclosure relates generally to wireless communications, and more specifically, to various time-hopping systems and techniques for wireless communications. 2. Background In conventional wireless communications, an access network is generally employed to support communications for a number of mobile devices. These access networks are typically implemented with multiple fixed site base stations dispersed throughout a geographic region. The geographic region is generally subdivided into smaller regions known as cells. Each base station may be configured to serve all mobile devices in its respective cell. As a result, the access network may not be easily reconfigured to account for varying traffic demands across different cellular regions. In contrast to the conventional access network, ad-hoc networks are dynamic. An ad-hoc network may be formed when a number of wireless communication devices, often referred to as terminals, decide to join together to form a network. Since terminals in ad-hoc networks operate as both hosts and routers, the network may be easily reconfigured to meet existing traffic demands in a more efficient fashion. Moreover, ad-hoc networks do not require the infrastructure required by conventional access networks, making ad-hoc networks an attractive choice for the future. A completely ad-hoc network consisting of peer-to-peer connections generally result in very inefficient communications. To improve efficiency, the terminals may organize themselves into a collection of piconets. A “piconet” is a group of terminals in close proximity to one another. The piconet may have a master terminal that schedules access to the communications medium for the terminals in its piconet. Numerous multiple access techniques exist to support communications in an ad-hoc network. A Frequency Division Multiple Access (FDMA) scheme, by way of example, is a very common technique. FDMA typically involves allocating distinct portions of the total bandwidth to individual communications between two terminals in the piconet. While this scheme may be effective for uninterrupted communications, better utilization of the total bandwidth may be achieved when such constant, uninterrupted communication is not required. Other multiple access schemes include Time Division Multiple Access (TDMA). These TDMA schemes may be particularly effective in allocating limited bandwidth among a number of terminals which do not require uninterrupted communications. TDMA schemes typically dedicate the entire bandwidth to each communication channel between two terminals at designated time intervals. Code Division Multiple Access (CDMA) techniques may be used in conjunction with TDMA to support multiple communications during each time interval. This may be achieved by transmitting each communication or signal in a designated time interval with a different code that modulates a carrier, and thereby, spreads the signal. The transmitted signals may be separated in the receiver terminal by a demodulator that uses a corresponding code to de-spread the desired signal. The undesired signals, whose codes do not match, are not de-spread and contribute only to noise. In TDMA systems that use spread-spectrum communications, each master terminal may schedule transmissions within its own piconet in a way that does not cause excessive mutual interference. However, it may be more difficult to manage interference from other piconets, or “inter-piconet interference”. Inter-piconet interference management generally involves the coordination of transmission schedules across multiple piconets. While this approach may be workable between a handful of master terminals, it may be problematic in larger networks due to scheduling delays and excessive overhead. Accordingly, a more robust and efficient scheduling algorithm is needed which addresses the problems of inter-piconet interference. | <SOH> SUMMARY <EOH>In one aspect of the present invention, a method of scheduling communications over a frame having a plurality of time slots includes assigning information to be transmitted between two terminals to a block of the time slots within a frame, and reordering the time slot assignments within the frame using a permutation function, the permutation function being a function of frame count. In another aspect of the present invention, a communications terminal includes a transceiver configured to receive a block of time slot assignments within a frame to communicate with a remote terminal, and a controller configured to reorder the time slot assignments within the frame using a permutation function, the permutation function being a function of frame count. In yet another aspect of the present invention, a communications terminal configured to operate in a first piconet includes a transceiver configured to receive a block of time slot assignments within a frame for a transmission between a bridge terminal and a terminal in a second piconet, the bridge terminal belonging to the first and second piconets, and a scheduler configured to reorder the time slot assignments within the frame using a permutation function for the second piconet, demap the reordered time slots within the frame using a permutation function for the first piconet, and use the demapped time slots as a constraint in assigning a block of time slots within the frame for a transmission between two terminals in the first piconet, the permutation for the first piconet being different from the permutation function for the second piconet. In a further aspect of the present invention, a communications terminal includes means for receiving a block of time slot assignments within a frame to communicate with a remote terminal, and means for reordering the time slot assignments within the frame using a permutation function, the permutation function being a function of frame count. It is understood that other embodiments of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein various embodiments of the invention are shown and described by way of illustration. As will be realized, the invention is capable of other and different embodiments and its several details are capable of modification in various other respects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive. | 20040108 | 20080805 | 20050714 | 63347.0 | 0 | HUYNH, NAM TRUNG | TIME-HOPPING SYSTEMS AND TECHNIQUES FOR WIRELESS COMMUNICATIONS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,754,797 | ACCEPTED | COOLING WATER SCALE AND CORROSION INHIBITION | A methods of the present invention for inhibiting silica scale formation and corrosion in aqueous systems where soluble silica residuals (SiO2) are maintained in excess of 200 mg/L, and source water silica deposition is inhibited with silica accumulations as high as 4000 mg/L (cycled accumulation) from evaporation and concentration of source water. The methods of the present invention also provides inhibition of corrosion for carbon steel at corrosion rates of less than 0.3 mpy (mils per year), and less than 0.1 mpy for copper, copper alloy, and stainless steel alloys in highly concentrated (high dissolved solids) waters. The methods of the present invention comprise pretreatment removal of hardness ions from the makeup source water, maintenance of electrical conductivity, and elevating the pH level of the aqueous environment. Thereafter, specified water chemistry residual ranges are maintained in the aqueous system to achieve inhibition of scale and corrosion. | 1. A method for controlling silica or silicate scale formation in an aqueous heat transfer water system with silica contributed by source water, the methods of the present invention comprising the steps: a) removing hardness ions from said source water; b) controlling the conductivity of said aqueous system water such that said aqueous system water possesses a conductivity from approximately 10,000 to 150,000 μmhos; and c) elevating and maintaining the pH of said aqueous system water such that said aqueous system water possesses a pH of approximately 9.0 or greater. d) providing a metallic heat transfer surface and cyclically contacting said aqueous system water thereabout. 2. The method of claim 1 wherein in step a), said hardness ions comprise ions of calcium and magnesium. 3. The method of claim 1 wherein said aqueous system water contains soluble SiO2 in excess of 200 mg/L. 4. The method of claim 3 wherein said aqueous system water contains soluble SiO2 in excess of 300 mg/L. 5. The methods of the present invention of claim 3 wherein in step a), said hardness ions are removed in amounts equal to or less than approximately 20% of the SiO2 present within said source water. 6. The methods of the present invention of claim 3 wherein in step a), said hardness ions are removed in amounts equal to or less than approximately 5% of the SiO2 present within said source water. 7. The method of claim 1 wherein in step c), said pH is maintained at 9.6 or higher. 8. The method of claim 1 wherein in step a), said hardness ions are removed via a method selected from the group consisting of ion exchange, selective ion removal with reverse osmosis, reverse osmosis, electro chemical removal, chemical precipitation, evaporation and distillation. 9. The method of claim 1 wherein in step c), said pH is increased by adding an alkali agent. 10. The method of claim 9 wherein said alkali agent comprises sodium hydroxide. 11. The method of claim 1 wherein in step c), said pH is elevated by evaporating a portion of said aqueous system water. 12. The method of claim 1 wherein in step c), said pH is elevated by distilling a portion of said aqueous system water. 13. The method of claim 1 wherein in step c), said source water comprises water utilized for cooling processes, water utilized for cooling tower systems, water utilized for evaporative cooling, water utilized for cooling lakes or ponds, water utilized for enclosed or secondary cooling and heating loops. 14. A method for inhibiting corrosion of a metallic substance in an aqueous system wherein said aqueous system derives water from make-up source water, the methods of the present invention comprising the steps: a) removing hardness ions from said source water; b) controlling the conductivity of said aqueous system water such that said aqueous system water possesses a conductivity from approximately 10,000 to 150,000 μmhos; and c) elevating and maintaining the pH of said aqueous system water such that said aqueous system water possesses a pH of approximately 9.0 or greater. 15. The method of claim 14 wherein in step a), said hardness ions comprise ions of calcium and magnesium. 16. The method of claim 14 wherein said aqueous system water contains soluble SiO2 in excess of 200 mg/L. 17. The method of claim 16 wherein said aqueous system water contains soluble SiO2 in excess of 300 mg/L. 18. The method of claim 14 wherein in step a), said hardness ions are removed in amounts equal to or less than approximately 20% of the SiO2 present within said source water. 19. The method of claim 16 wherein in step a), said hardness ions are removed in amounts equal to or less than approximately 5% of the SiO2 present within said source water. 20. The method of claim 14 wherein in step c), said pH is maintained at 9.6 or higher. 21. The method of claim 14 wherein in step a), said hardness ions are removed via a method selected from the group consisting of ion exchange, selective ion removal with reverse osmosis, reverse osmosis, electro chemical removal, chemical precipitation, evaporation and distillation. 22. The method of claim 14 wherein in step c), said pH is increased by adding an alkali agent. 23. The method of claim 22 wherein said alkali agent comprises sodium hydroxide. 24. The method of claim 14 wherein in step c), said pH is elevated by evaporating a portion of said aqueous system water. 25. The method of claim 14 wherein in step c), said pH is elevated by distilling a portion of said aqueous system water. 26. The method of claim 14 wherein said metallic substrate is selected from the group consisting of carbon steel, copper, copper alloy and stainless steel alloy. 27. The method of claim 1 wherein prior to step a), said methods of the present invention comprises the step: a) analyzing said source water to determine the concentration of SiO2 present therein. 28. The method of claim 14 wherein prior to step a), said methods of the present invention comprises the step: a) analyzing said source water to determine the concentration of SiO2 present therein. 29. The method of claim 1 wherein in step b), said conductivity of said aqueous system water is controlled such that said aqueous system water possesses a conductivity from approximately 20,000 to 150,000 μmhos. 30. The method of claim 14 wherein in step b), said conductivity of said aqueous system water is controlled such that said aqueous system water possesses a conductivity from approximately 20,000 to 150,000 μmhos. 31. The method of claim 1, wherein said source water contains silica in an amount of 4000 mg/L or less. | CROSS-REFERENCE TO RELATED APPLICATIONS Not Applicable STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT Not Applicable BACKGROUND OF THE INVENTION Silica is one of the major scale and fouling problems in many processes using water. Silica is difficult to deal with because it can assume many low solubility chemical forms depending on the water chemistry and metal surface temperature conditions. Below about pH 9.0, monomeric silica has limited solubility (125-180 mg/L as SiO2) and tends to polymerize as these concentrations are exceeded to form insoluble (amorphous) oligomeric or colloidal silica. At higher pH, particularly above about pH 9.0, silica is soluble at increased concentrations of the monomeric silicate ion or in the multimeric forms of silica. Since conversion can be slow, all of these forms may exist at any one time. The silicate ion can react with polyvalent cations like magnesium and calcium commonly present in process waters to produce salts with very limited solubility. Thus it is common for a mixture of many forms to be present: monomeric, oligomeric and colloidal silica; magnesium silicate, calcium silicate and other silicate salts. In describing this complex system, it is common practice to refer to the mixture merely as silica or as silica and silicate. Herein these terms are used interchangeably. To address such problem, methods of the present inventions for controlling deposition and fouling of silica or silicate salts on surfaces in a aqueous process have been derived and include: 1) inhibiting precipitation of the material from the process water; 2) dispersing precipitated material after it has formed in the bulk water; 3) maintaining an aqueous chemical environment that supports formation of increased residuals of soluble silica species; and 4) producing a non-adherent form of silica precipitants in the bulk water. The exact mechanism by which specific scale inhibition methods of the present inventions function is not well understood. In industrial application, most scale and corrosion control methods of the present inventions used in aqueous systems typically rely on the addition of a scale and corrosion inhibitor in combination with controlled wastage of system water to prevent scale and corrosion problems. In this regard, the major scale formation potentials are contributed by the quantity of hardness (calcium and magnesium) and silica ions contributed by the source water, while the major corrosive potential results from the ionic or electrolytic strength in the system water. Treatment methods of the present inventions to minimize corrosion have further generally relied on the addition of chemical additives that inhibit corrosion through suppression of corrosive reactions occurring at either the anode or the cathode present on the metal surface, or combinations of chemical additives that inhibit reactions at both the anode and cathode. The most commonly applied anodic inhibitors include chromate, molybdate, orthophosphate, nitrite and silicate whereas the most commonly applied cathodic inhibitors include polyphosphate, zinc, organic phosphates and calcium carbonate. In view of toxicity and environmental concerns, the use of highly effective heavy metal corrosion inhibitors, such as chromate, have been strictly prohibited and most methods of the present inventions now rely on a balance of the scale formation and corrosive tendencies of the system water and are referred to in the art as alkaline treatment approaches. This balance, as applied in such treatment approaches, is defined by control of system water chemistry with indices such as LSI or Ryznar, and is used in conjunction with combinations of scale and corrosion inhibitor additives to inhibit scale formation and optimize corrosion protection at maximum concentration of dissolved solids in the source water. These methods of the present inventions, however, are still limited by the maximum concentration of silica and potential for silicate scale formation. Moreover, corrosion rates are also significantly higher than those available with use of heavy metals such as chromate. Along these lines, since the use of chromate and other toxic heavy metals has been restricted, as discussed above, corrosion protection has generally been limited to optimum ranges of 2 to 5 mils per year (mpy) for carbon steel when treating typical source water qualities with current corrosion control methods of the present inventions. Source waters that are high in dissolved solids or are naturally soft are even more difficult to treat, and typically have even higher corrosion rates. In an alternative approach, a significant number of methods of the present inventions for controlling scale rely on addition of acid to treated systems to control pH and reduce scaling potentials at higher concentrations of source water chemistry. Such method allows conservation of water through modification of the concentrated source water, while maintaining balance of the scale formation and corrosive tendencies of the water. Despite such advantages, these methods of the present inventions have the drawback of being prone to greater risk of scale and/or corrosion consequences with excursions with the acid/pH control system. Moreover, there is an overall increase in corrosion potential due to the higher ionic or electrolytic strength of the water that results from addition of acid ions that are concentrated along with ions in the source water. Lower pH corrosion control methods of the present inventions further rely on significantly higher chemical additive residuals to offset corrosive tendencies, but are limited in effectiveness without the use of heavy metals. Silica concentration must still be controlled at maximum residuals by system water wastage to avoid potential silica scaling. In a further approach, source water is pretreated to remove hardness ions in a small proportion of systems to control calcium and magnesium scale potentials. These applications, however, have still relied on control of silica residuals at previous maximum guideline levels through water wastage to prevent silica scale deposits. Corrosion protection is also less effective with softened water due to elimination of the balance of scale and corrosion tendency provided by the natural hardness in the source water. Accordingly, there is a substantial need in the art for methods of the present inventions that are efficiently operative to inhibit corrosion and scale formation that do not rely upon the use of heavy metals, extensive acidification and/or water wastage that are known and practiced in the prior art. There is additionally a need in the art for such processes that, in addition to being efficient, are extremely cost-effective and environmentally safe. Exemplary of those processes that would likely benefit from such methods of the present inventions would include cooling water processes, cooling tower systems, evaporative coolers, cooling lakes or ponds, and closed or secondary cooling and heating loops. In each of these processes, heat is transferred to or from the water. In evaporative cooling water processes, heat is added to the water and evaporation of some of the water takes place. As the water is evaporated, the silica (or silicates) will concentrate and if the silica concentration exceeds its solubility, it can deposit to form either a vitreous coating or an adherent scale that can normally be removed only by laborious mechanical or chemical cleaning. Along these lines, at some point in the above processes, heat is extracted from the water, making any dissolved silicate less soluble and thus further likely to deposit on surfaces, thus requiring removal. Accordingly, a methods of the present invention for preventing fouling of surfaces with silica or silicates, that further allows the use of higher levels of silica/silicates for corrosion control would be exceptionally advantageous. In this respect for cooling water, an inhibition method has long been sought after that would enable silica to be used as a non-toxic and environmentally friendly corrosion inhibitor. To address these specific concerns, the current practice in these particular processes is to limit the silica or silicate concentration in the water so that deposition from these compounds does not occur. For example in cooling water, the accepted practice is to limit the amount of silica or silicates to about 150 mg/L, expressed as SiO2. Reportedly, the best technology currently available for control of silica or silicates in cooling water is either various low molecular weight polymers, various organic phosphate chemistries, and combinations thereof. Even with use of these chemical additives, however, silica is still limited to 180 mg/L in most system applications. Because in many arid areas of the U.S. and other parts of the world make-up water may contain from 50-90 mg/L silica, cooling water can only be concentrated 2 to 3 times such levels before the risk of silica or silicate deposition becomes too great. A method that would enable greater re-use or cycling of this silica-limited cooling water would be a great benefit to these areas. SUMMARY OF THE INVENTION The present invention specifically addresses and alleviates the above-identified deficiencies in the art. In this regard, the invention relates to methods for controlling silica and silicate fouling problems, as well as corrosion of system metallurgy (i.e. metal substrates) in aqueous systems with high concentrations of dissolved solids. More particularly, the invention is directed to the removal of hardness ions from the source water and control of specified chemistry residuals in the aqueous system to inhibit deposition of magnesium silicate and other silicate and silica scales on system surfaces, and to inhibit corrosion of system metallurgy. To that end, we have unexpectedly discovered that the difficult silica and silicate scaling problems that occur in aqueous systems when silica residuals exceed 200 mg/L as SiO2 or reach as high as 4000 mg/L of silica accumulation (cycled accumulation from source water) can be controlled by initially removing hardness ions (calcium and magnesium) from the makeup source water (i.e., water fed to the aqueous system) using pretreatment methods of the present inventions known in the art, such as through the use of ion exchange resins, selective ion removal with reverse osmosis, reverse osmosis, electrochemical removal, chemical precipitation, or evaporation/distillation. Preferably, the pretreatment methods of the present invention will maintain the total hardness in the makeup water at less than 20% of the makeup silica residual (mg/L SiO2), as determined from an initial assessment of the source water. In some embodiments, the total hardness ions will be maintained at less than 5% of the makeup silica residual. When source makeup water is naturally soft, with less than 10 mg/L hardness as CaCO3, pretreatment removal of hardness ions may be bypassed in some systems. Thereafter, the conductivity (non-neutralized) in the aqueous system is controlled such that the same is maintained between 10,000 and 150,000 μmhos, and preferably between 20,000 to 150,000 μmhos and the pH of the source water elevated to a pH of 9.0, and preferably 9.6, or higher. With respect to the latter, the pH may be adjusted by the addition of an alkaline agent, such as sodium hydroxide, or by simply removing a portion of the aqueous system water through such well known techniques or processes as evaporation and/or distillation. In a related application, we have unexpectedly discovered that the excessive corrosion of carbon steel, copper, copper alloys, and stainless steel alloys in aqueous systems due to high ionic strength (electrolytic potential) contributed by high dissolved solids source water or highly cycled (10,000 to 150,000 μmhos non-neutralized conductivity) systems can likewise be controlled by the methods of the present inventions of the present invention. In such context, the methods of the present invention comprises removing hardness ions (calcium and magnesium) from the makeup source water using known pretreatment methods of the present inventions, such as ion exchange resins, selective ion removal with reverse osmosis, reverse osmosis, electrochemical removal, chemical precipitation, or evaporation/distillation. The pretreatment methods of the present invention will preferably maintain the total hardness ratio in the makeup water at less than 20%, and preferably at least less than 5%, of the makeup silica residual (mg/L SiO2), as determined from an initial analysis of the source water. When source makeup water is naturally soft, with less than 10 mg/L hardness as CaCO3, pretreatment removal of hardness ions may be bypassed in some systems. Thereafter, the conductivity (non-neutralized) in the aqueous system is controlled such that the same is maintained between 10,000 and 150,000, and more preferably 20,000 to 150,000, μmhos. Alkalinity is then controlled as quantified by pH at 9.0 or higher, with a pH of 9.6 being more highly desired in some applications. Control of soluble silica at a minimum residual concentration of 200 mg/L as SiO2 to support corrosion inhibition. With respect to the latter, the SiO2 may be adjusted by the addition of a silica/silicate agent, such as sodium silicate, or by simply removing a portion of the aqueous system water through such well known techniques or processes as evaporation and/or distillation. DETAILED DESCRIPTION OF THE INVENTION The detailed description set forth below is intended as a description of the presently preferred embodiment of the invention, and is not intended to represent the only form in which the present invention may be constructed or utilized. The description sets forth the functions and sequences of steps for constructing and operating the invention. It is to be understood, however, that the same or equivalent functions and sequences may be accomplished by different embodiments and that they are also intended to be encompassed within the scope of the invention. According to the present invention, there is disclosed methods for inhibiting silica and silicate scale in aqueous systems and providing exceptional metal corrosion protection that comprise the removal of hardness from the makeup source water prior to being fed into the aqueous system and thereafter controlling the aqueous system within specified water chemistry control ranges. Specifically, hardness ions (calcium and magnesium) are removed from the makeup source water using pretreatment methods known in the art, which include methods such as ion exchange resins, selective ion removal with reverse osmosis, reverse osmosis, electrochemical removal, chemical precipitation, or evaporation/distillation. The pretreatment methods will preferably maintain the total hardness ratio in the makeup water at less than 20% of the makeup silica residual (mg/L SiO2). In a more highly preferred embodiment, the pretreatment methods will maintain the total hardness ions present in the makeup water at less than 5% of the makeup silica residual. As will be appreciated by those skilled in the art, the silica residual can be readily determined by utilizing known techniques, and will preferably be determined prior to the application of the methods of the present invention. Along these lines, when source makeup water is naturally soft, with less than 10 mg/L hardness as CaCO3, pretreatment removal of hardness ions may be bypassed in some systems. Conductivity (non-neutralized) is controlled in the aqueous system such that the same is between approximately 10,000 and 150,000 μmhos through control or elimination of blowdown wastage from the system. In a more highly preferred embodiment, conductivity will be maintained between approximately 20,000 and 150,000 μmhos. The higher level of ionic strength in this control range increases the solubility of multivalent metal salts that are less soluble at lower ionic strengths of other methods of the present inventions. This residual control parameter also provides indirect control of silica and alkalinity (pH) residuals contributed by concentration of naturally available silica and alkalinity in the source water or by addition of adjunct forms of these chemicals. Aqueous system pH is maintained at 9.0 or greater as contributed by the cycled accumulation of alkalinity from the source water or through supplemental addition of an alkalinity adjunct, such as sodium hydroxide, to the system when required. The minimum pH will provide increased solubility of silica and control of silicate scale and support corrosion protection for metals. Along these lines, in certain preferred embodiments of the present invention, the pH may be raised and maintained to a level of 9.6 of higher. Silica residuals (soluble) will be maintained in the system at levels of greater than 200 mg/L as contributed by the cycled accumulation of silica from the source water or through supplemental addition of adjunct forms of silica to the system when required. In certain applications, such levels may be maintained at levels of greater than 300 mg/L. The minimum residual of soluble silica will support corrosion inhibition for metals, and more particularly, inhibit corrosion of carbon steel to less than 0.3 mpy and less than 0.1 mpy for copper, copper alloys and stainless steel alloys present in the aqueous system. With respect to the mechanisms by which the methods of the present inventions effectively achieve their results, excess source water silica (beyond the soluble residuals attained with specified pH control) is probably adsorbed as non-adherent precipitates that form following reaction with small amounts of metals (Ca, Mg, Fe, Al, Zn) or solids introduced by source water or scrubbed from the air by the tower system. This is the probable result of the expanded solubility of the monomeric and multimeric species of silica with the methods of the present invention that impede polymerization of excess silica until it reacts with these incrementally introduced adsorption materials to form small quantities of non-adherent precipitants. The adsorption and precipitation of high ratios of silica on small amounts of solids such as magnesium hydroxide has been demonstrated by the Freundlich isotherms, and is common experience in water treatment chemical precipitation processes. The small quantity of precipitate is removed from the circulating water through settling in the tower basin or drift losses. Control of the lower solubility hardness scale formations and resultant nucleation sites on cooling system surfaces are controlled with the methods of the present invention disclosed herein, through pretreatment removal of the majority of the scale forming (hardness) metal ions and control of system water at the specified higher ionic strength control ranges. The higher level of ionic strength in this control range increases the solubility of scale forming metal salts. Such approach is well suited to address a further complication in controlling silica and silicate fouling brought about from the phenomena that colloidal silica tends to be more soluble as temperature is raised, while the polyvalent metal salts of the silicate ion tend to be less soluble with increasing temperature. As a result, control or minimization of polyvalent metals in the aqueous solution will prohibit formation of the insoluble salts on heat transfer surfaces, and promote increased solubility of other forms of silica at the elevated temperatures of heat transfer surfaces. The present methods thereby eliminate potential reaction of insoluble silica forms with hardness scale or metal salt deposits on system surfaces and their nucleation sites that initiate silica or silicate scale formations. The higher residuals of soluble silica and higher pH levels maintained via the present methods of the present inventions provide highly effective polarization (corrosion barrier formation) and exceptional corrosion protection for carbon steel, copper, copper alloy and stainless steel metals (less than 0.3 mpy for mild steel, and less than 0.1 mpy copper, copper alloy, and stainless steel). Comparable corrosion rates for carbon steel in aqueous systems with existing methods of the present inventions are optimally in the range of 2 to 5 mpy. Though not fully understood, several corrosion inhibition mechanisms are believed to be contributing to the metals corrosion protection provided by the methods of the present inventions of the present invention, and the synergy of both anodic and cathodic inhibition functions may contribute to the corrosion inhibition process. An anodic corrosion inhibitor mechanism results from increased residuals of soluble silica provided by the present methods, particularly in the multimeric form. Silicates inhibit aqueous corrosion by hydrolyzing to form negatively charged colloidal particles. These particles migrate to anodic sites and precipitate on the metal surfaces where they react with metallic ion corrosion products. The result is the formation of a self-repairing gel whose growth is self-limited through inhibition of further corrosion at the metal surface. Unlike the monomeric silica form normally found in source water that fails to provide effective corrosion inhibition, the methods of the present invention provide such beneficial effect by relying upon the presence and on control of total soluble silica residuals, with conversion of natural monomeric silica to the multimeric forms of silica at much higher levels, through application of the combined control ranges as set forth above. In this regard, the removal of most source water calcium and magnesium ions is operative to prevent reaction and adsorption of the multimeric silica forms on the metal oxide or metal salt precipitates from source water, which is believed to be an important contribution to the effectiveness of this corrosion inhibition mechanism afforded by the present invention. The resultant effective formation and control of the multimeric silica residuals with such methods of the present invention has not heretofore been available. In addition to an anodic corrosion inhibition mechanism, a cathodic inhibition mechanism is also believed to be present. Such inhibition is caused by an increased hydroxyl ion concentration provided with the higher pH control range utilized in the practice of the present invention. In this regard, iron and steel are generally considered passive to corrosion in the pH range of 10 to 12. The elevated residual of hydroxyl ions supports equilibrium with hydroxyl ion produced during oxygen reduction at the cathode, and increases hydroxyl ion availability to react with iron to form ferrous hydroxide. As a consequence, ferrous hydroxide precipitates form at the metal surface due to very low solubility. The ferrous hydroxide will further oxidize to ferric oxide, but these iron reaction products remain insoluble at the higher pH levels attained by implementing the methods described herein to polarize or form a barrier that limits further corrosion. At the 9 to 10 pH range (as utilized in the practice of the present invention), effective hydroxyl ion passivation of metal surfaces may be aided by the pretreatment reduction of hardness ions (calcium and magnesium) in the source water that may compete with this reaction and interfere with metal surface barrier formation. Galvanized steel and aluminum may be protected in general by the silicate corrosion inhibitor mechanism discussed herein, but protective films may be destabilized at water-air-metal interfaces. Steel, copper, copper alloy, stainless steel, fiberglass, and plastic are thus ideal aqueous system materials for application of the methods of the present inventions of the present invention. The extensive improvement in corrosion protection provided by the methods of the present invention is not normally attainable with prior art methods when they utilize significantly higher residuals of aggressive ions (e.g., chloride and sulfate) and the accompanying greater ionic or electrolytic strength present in the aqueous system water. This may result from either use of acid for scale control and/or concentration of source water ions in the aqueous system. As is known, corrosion rates generally increase proportionately with increasing ionic strength. Accordingly, through the ability to protect system metals exposed to this increased electrolytic corrosion potential, opportunity for water conservation and environmental benefits that result with elimination of system discharge used with previous methods to reduce corrosion or scaling problems in aqueous systems can be readily realized through the practice of the methods disclosed herein. Still further, the methods of the present inventions of the present invention can advantageously provide gradual removal of hardness scale deposits from metal surfaces. This benefit is accomplished through both pretreatment removal of the majority of the scale forming (hardness) metal ions and control of system water at the specified higher ionic strength control ranges. Solubility of hardness salts is increased by the higher ionic strength (conductivity) provided by the present methods of the present invention, which has been determined with high solids water such as seawater, and may contribute to the increased solubility of deposits present within the aqueous environment so treated. Studies conducted with hardness scale coated metal coupons in treated systems demonstrated a significant deposit removal rate for CaCO3 scale films in ten days. Control of source water hardness at lower specified residuals will probably be required to achieve optimum rate of hardness scale removal. Furthermore, the present methods advantageously prohibits microorganism propagation due to the higher pH and dissolved solids levels that are attained. Biological fouling potentials are thus significantly reduced. In this regard, the methods of the present inventions disclosed herein create a chemical environment that inhibits many microbiological species that propagate at the pH and dissolved solids chemistry ranges used with previous treatment approaches. The reduction in aqueous system discharge also permits use of residual biocides at more effective and economical dosages that impede development of problem concentrations of any microbiological species that are resilient in the aqueous environment generated through the practice of the methods of the present inventions disclosed herein. A still further advantage of the methods of the present invention include the ability of the same to provide a lower freeze temperature in the aqueous system, comparable to ocean water, and avert potential mechanical damage from freezing and/or operational restrictions for systems located in freeze temperature climates. Additional modifications and improvements of the present invention may also be apparent to those of ordinary skill in the art. Thus, the particular combination of parts and steps described and illustrated herein is intended to represent only certain embodiments of the present invention, and is not intended to serve as limitations of alternative devices and methods of the present inventions within the spirit and scope of the invention. For example, since the methods of the present invention provides both effective silicate scale control and corrosion inhibition when using high silica or high dissolved solids source waters, extensive variation in source water quality can be tolerated. These source waters might otherwise be unacceptable and uneconomical for use in such aqueous systems. In addition, such modifications may include, for example, using other conventional water treatment chemicals along with the methods of the present invention, and could include other scale inhibitors, such as for example phosphonates, to control scales other than silica, corrosion inhibitors, biocides, dispersants, defoamers and the like. Accordingly, the present invention should be construed as broadly as possible. As an illustration, below there are provided non-restrictive examples of an aqueous water system that has been treated with methods conforming to the present invention. EXAMPLES OF SILICATE SCALE INHIBITOR METHOD The following analytical tests were performed on a cooling tower system treated with the methods of the present invention to demonstrate the efficacy of the present invention for controlling the solubility of silica and silicate species, and preventing scale deposition of these species. Two samples of each of the following: 1) varying source water; 2) the resultant treated system water; and 3) tower sump insoluble accumulations, for a total of six samples were analyzed from different operating time frames. Although the exact mechanism of action of the process is not completely understood, the methods of the present invention minimize the turbidity of the treated water, which is considered a demonstration of an effective silica and silicate scale inhibitor. Methods that produce treated water of less than eight nephelometric turbidity units (NTU) are considered improvements over the current available technology. Turbidity measurements (Table 1) performed on samples taken from the cooling systems, before and after filtration through a 0.45-micron filter, illustrate effective silicate inhibition in the treated water. The turbidity levels are well below typical cooling tower systems, in particular at such high concentrations (80 COC), and indicate the methods of the present invention provide controlled non-adherent precipitation of excess silica and other insoluble materials entering the system. Clean heat exchanger surfaces have confirmed that the method silica precipitation is non-adherent. The precipitated silica forms are contained in the cooling tower sump. However, the volume of precipitant and scrubbed accumulations in the tower sump were not appreciably greater than previous treatment methods due to reduction of insoluble multivalent metal salt precipitates by pretreatment removal. TABLE 1 Tower Water Turbidity Analyses Sample No. 1: (Turbidity, NTU) Neat, 4 NTU; Filtered, 2 NTU Sample No. 2: (Turbidity, NTU) Neat, 3 NTU The cooling tower and makeup water analytical tests performed in Table 2 and Table 3 illustrate the effectiveness of the methods of the present invention in maintaining higher levels of soluble silica in the cooling tower system when parameters are controlled within the specified pH and low makeup hardness ranges. Soluble silica residuals are present at 306 and 382 mg/L in these tower samples at the respective 9.6 and 10.0 pH levels. The lower cycles of concentration (COC) for silica in these tower samples, as compared to the higher cycled residuals for soluble chemistries (chloride, alkalinity, conductivity), indicate that excess silica is precipitating as non-adherent material, and accumulating in the tower basin. This is confirmed by the increased ratio of silica forms found in tower basin deposit analyses. System metal and heat exchange surfaces were free of silica or other scale deposits. TABLE 2 Cooling Tower Sampl No. 1/Makeup/Residual Ratios (COC) SAMPLE/TESTS Tower (*adjunct) Makeup (soft) COC Conductivity, 33,950 412 82.4 μmhos (Un-neutralized) pH 10.01 8.23 NA Turbidity, NTUs 3 0.08 NA Neat Filtered (0.45 μ) — — — Copper, mg/L Cu ND ND NA Zinc, mg/L ND ND NA Silica, mg/L SiO2 382 9.5 40.2 Calcium, mg/L 16.0 0.20 NA CaCO3 Magnesium, mg/L 3.33 0.05 NA CaCO3 Iron, mg/L Fe ND ND NA Aluminum, mg/L ND ND NA Al Phosphate, mg/L ND ND NA PO4 Chloride, mg/L 6040 80 75.5 Tot. Alkalinity, 13200 156 84.6 mg/L ND = Not Detectable; NA = Not Applicable; COC = Cycles of Concentration TABLE 3 Cooling Tower Sample No. 2/Makeup/Residual Ratios (COC) SAMPLE/TESTS Tower (no adjunct) Makeup (soft) COC Conductivity, 66,700 829 80 μmhos (Un-neutralized) pH 9.61 7.5 NA Turbidity, NTUs 4 0.08 NA Neat Filtered (0.45 μ) 2 — — Zinc, mg/L ND ND NA Silica, mg/L SiO2 306.4 11 28 Calcium, mg/L 21.5 0.20 NA CaCO3 Magnesium, mg/L 0.65 0.05 NA CaCO3 Iron, mg/L Fe ND ND NA Aluminum, mg/L ND ND NA Al Phosphate, mg/L ND ND NA PO4 ND = Not Detectable; NA = Not Applicable; COC = Cycles of Concentration Microscopic and chemical analysis of deposit samples from accumulated residue in the tower basin of a system treated by present methodology are shown in Exhibit 1 and Exhibit 2. Both analyses illustrate the significant ratio of silica materials in the deposit. The major proportion of this silica is the probable result of silica adsorption or reaction with insoluble precipitates of multivalent metals as they concentrated in the tower water. Visual inspections of heat transfer equipment in the system treated by this method have confirmed that it has remained free of silica and other scale deposits. System heat transfer efficiencies were also maintained at minimum fouling factor levels. DEPOSIT DESIGNATION: Cooling Tower Basin Deposit % ESTIMATED CONSTITUENTS Exhibit 1 MICROSCOPICAL ANALYSIS - POLARIZED LIGHT MICROSCOPY >30 Amorphous silica, including assorted diatoms, probably including amorphous magnesium silicate; calcium carbonate (calcite) 1-2 Assorted clay material including feldspar; hydrated iron oxide; carbonaceous material <1 Silicon dioxide (quartz); assorted plant fibers; unidentified material including possibly aluminum oxide (corundum) Exhibit 2 CHEMICAL ANALYSIS - DRIED SAMPLE 12.1 CaO 8.5 MgO 5.2 Fe3O4 3.7 Fe2O3 <0.5 Al2O3 13.2 Carbonate, CO2 51.1 SiO2 5.7 Loss on Ignition Most probable combinations: Silica ˜54%, Calcium Carbonate ˜32%, Oxides of Iron ˜9%, Mg and Al Oxides ˜5%. EXAMPLES OF CORROSION INHIBITION METHODS OF THE PRESENT INVENTION The data in Table 4 illustrate the effectiveness of the methods of the present invention in inhibiting corrosion for carbon steel and copper metals evaluated by weight loss coupons in the system. No pitting was observed on coupon surfaces. Equipment inspections and exchanger tube surface testing have confirmed excellent corrosion protection. Comparable corrosion rates for carbon steel in this water quality with existing methods of the present inventions are optimally in the range of 2 to 5 mpy. TABLE 4 CORROSION TEST DATA Specimen Type Carbon Steel Copper Test location Tower Loop Tower loop Exposure period 62 Days 62 Days Corrosion Rate (mpy) 0.3 <0.1 EXAMPLES OF SCALE DEPOSIT REMOVAL The data in Table 5 illustrate harness (CaCO3) scale removal from metal surfaces in a tower system treated with the methods of the present invention through coupon weight loss reduction. Standard metal coupons that were scaled with CaCO3 film were weighed before and after ten days of exposure and the visible removal of most of the scale thickness. The demonstrated CaCO3 weight loss rate will provide gradual removal of hardness scale deposits that have occurred in a system prior to method treatment. TABLE 5 SCALE DEPOSIT REMOVAL TEST DATA Specimen Type Carbon Steel Copper Test location Tower Loop Tower loop Exposure period 10 Days 10 Days Scale Removal (mpy) 8.3 8.1 | <SOH> BACKGROUND OF THE INVENTION <EOH>Silica is one of the major scale and fouling problems in many processes using water. Silica is difficult to deal with because it can assume many low solubility chemical forms depending on the water chemistry and metal surface temperature conditions. Below about pH 9.0, monomeric silica has limited solubility (125-180 mg/L as SiO 2 ) and tends to polymerize as these concentrations are exceeded to form insoluble (amorphous) oligomeric or colloidal silica. At higher pH, particularly above about pH 9.0, silica is soluble at increased concentrations of the monomeric silicate ion or in the multimeric forms of silica. Since conversion can be slow, all of these forms may exist at any one time. The silicate ion can react with polyvalent cations like magnesium and calcium commonly present in process waters to produce salts with very limited solubility. Thus it is common for a mixture of many forms to be present: monomeric, oligomeric and colloidal silica; magnesium silicate, calcium silicate and other silicate salts. In describing this complex system, it is common practice to refer to the mixture merely as silica or as silica and silicate. Herein these terms are used interchangeably. To address such problem, methods of the present inventions for controlling deposition and fouling of silica or silicate salts on surfaces in a aqueous process have been derived and include: 1) inhibiting precipitation of the material from the process water; 2) dispersing precipitated material after it has formed in the bulk water; 3) maintaining an aqueous chemical environment that supports formation of increased residuals of soluble silica species; and 4) producing a non-adherent form of silica precipitants in the bulk water. The exact mechanism by which specific scale inhibition methods of the present inventions function is not well understood. In industrial application, most scale and corrosion control methods of the present inventions used in aqueous systems typically rely on the addition of a scale and corrosion inhibitor in combination with controlled wastage of system water to prevent scale and corrosion problems. In this regard, the major scale formation potentials are contributed by the quantity of hardness (calcium and magnesium) and silica ions contributed by the source water, while the major corrosive potential results from the ionic or electrolytic strength in the system water. Treatment methods of the present inventions to minimize corrosion have further generally relied on the addition of chemical additives that inhibit corrosion through suppression of corrosive reactions occurring at either the anode or the cathode present on the metal surface, or combinations of chemical additives that inhibit reactions at both the anode and cathode. The most commonly applied anodic inhibitors include chromate, molybdate, orthophosphate, nitrite and silicate whereas the most commonly applied cathodic inhibitors include polyphosphate, zinc, organic phosphates and calcium carbonate. In view of toxicity and environmental concerns, the use of highly effective heavy metal corrosion inhibitors, such as chromate, have been strictly prohibited and most methods of the present inventions now rely on a balance of the scale formation and corrosive tendencies of the system water and are referred to in the art as alkaline treatment approaches. This balance, as applied in such treatment approaches, is defined by control of system water chemistry with indices such as LSI or Ryznar, and is used in conjunction with combinations of scale and corrosion inhibitor additives to inhibit scale formation and optimize corrosion protection at maximum concentration of dissolved solids in the source water. These methods of the present inventions, however, are still limited by the maximum concentration of silica and potential for silicate scale formation. Moreover, corrosion rates are also significantly higher than those available with use of heavy metals such as chromate. Along these lines, since the use of chromate and other toxic heavy metals has been restricted, as discussed above, corrosion protection has generally been limited to optimum ranges of 2 to 5 mils per year (mpy) for carbon steel when treating typical source water qualities with current corrosion control methods of the present inventions. Source waters that are high in dissolved solids or are naturally soft are even more difficult to treat, and typically have even higher corrosion rates. In an alternative approach, a significant number of methods of the present inventions for controlling scale rely on addition of acid to treated systems to control pH and reduce scaling potentials at higher concentrations of source water chemistry. Such method allows conservation of water through modification of the concentrated source water, while maintaining balance of the scale formation and corrosive tendencies of the water. Despite such advantages, these methods of the present inventions have the drawback of being prone to greater risk of scale and/or corrosion consequences with excursions with the acid/pH control system. Moreover, there is an overall increase in corrosion potential due to the higher ionic or electrolytic strength of the water that results from addition of acid ions that are concentrated along with ions in the source water. Lower pH corrosion control methods of the present inventions further rely on significantly higher chemical additive residuals to offset corrosive tendencies, but are limited in effectiveness without the use of heavy metals. Silica concentration must still be controlled at maximum residuals by system water wastage to avoid potential silica scaling. In a further approach, source water is pretreated to remove hardness ions in a small proportion of systems to control calcium and magnesium scale potentials. These applications, however, have still relied on control of silica residuals at previous maximum guideline levels through water wastage to prevent silica scale deposits. Corrosion protection is also less effective with softened water due to elimination of the balance of scale and corrosion tendency provided by the natural hardness in the source water. Accordingly, there is a substantial need in the art for methods of the present inventions that are efficiently operative to inhibit corrosion and scale formation that do not rely upon the use of heavy metals, extensive acidification and/or water wastage that are known and practiced in the prior art. There is additionally a need in the art for such processes that, in addition to being efficient, are extremely cost-effective and environmentally safe. Exemplary of those processes that would likely benefit from such methods of the present inventions would include cooling water processes, cooling tower systems, evaporative coolers, cooling lakes or ponds, and closed or secondary cooling and heating loops. In each of these processes, heat is transferred to or from the water. In evaporative cooling water processes, heat is added to the water and evaporation of some of the water takes place. As the water is evaporated, the silica (or silicates) will concentrate and if the silica concentration exceeds its solubility, it can deposit to form either a vitreous coating or an adherent scale that can normally be removed only by laborious mechanical or chemical cleaning. Along these lines, at some point in the above processes, heat is extracted from the water, making any dissolved silicate less soluble and thus further likely to deposit on surfaces, thus requiring removal. Accordingly, a methods of the present invention for preventing fouling of surfaces with silica or silicates, that further allows the use of higher levels of silica/silicates for corrosion control would be exceptionally advantageous. In this respect for cooling water, an inhibition method has long been sought after that would enable silica to be used as a non-toxic and environmentally friendly corrosion inhibitor. To address these specific concerns, the current practice in these particular processes is to limit the silica or silicate concentration in the water so that deposition from these compounds does not occur. For example in cooling water, the accepted practice is to limit the amount of silica or silicates to about 150 mg/L, expressed as SiO 2 . Reportedly, the best technology currently available for control of silica or silicates in cooling water is either various low molecular weight polymers, various organic phosphate chemistries, and combinations thereof. Even with use of these chemical additives, however, silica is still limited to 180 mg/L in most system applications. Because in many arid areas of the U.S. and other parts of the world make-up water may contain from 50-90 mg/L silica, cooling water can only be concentrated 2 to 3 times such levels before the risk of silica or silicate deposition becomes too great. A method that would enable greater re-use or cycling of this silica-limited cooling water would be a great benefit to these areas. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention specifically addresses and alleviates the above-identified deficiencies in the art. In this regard, the invention relates to methods for controlling silica and silicate fouling problems, as well as corrosion of system metallurgy (i.e. metal substrates) in aqueous systems with high concentrations of dissolved solids. More particularly, the invention is directed to the removal of hardness ions from the source water and control of specified chemistry residuals in the aqueous system to inhibit deposition of magnesium silicate and other silicate and silica scales on system surfaces, and to inhibit corrosion of system metallurgy. To that end, we have unexpectedly discovered that the difficult silica and silicate scaling problems that occur in aqueous systems when silica residuals exceed 200 mg/L as SiO 2 or reach as high as 4000 mg/L of silica accumulation (cycled accumulation from source water) can be controlled by initially removing hardness ions (calcium and magnesium) from the makeup source water (i.e., water fed to the aqueous system) using pretreatment methods of the present inventions known in the art, such as through the use of ion exchange resins, selective ion removal with reverse osmosis, reverse osmosis, electrochemical removal, chemical precipitation, or evaporation/distillation. Preferably, the pretreatment methods of the present invention will maintain the total hardness in the makeup water at less than 20% of the makeup silica residual (mg/L SiO 2 ), as determined from an initial assessment of the source water. In some embodiments, the total hardness ions will be maintained at less than 5% of the makeup silica residual. When source makeup water is naturally soft, with less than 10 mg/L hardness as CaCO 3 , pretreatment removal of hardness ions may be bypassed in some systems. Thereafter, the conductivity (non-neutralized) in the aqueous system is controlled such that the same is maintained between 10,000 and 150,000 μmhos, and preferably between 20,000 to 150,000 μmhos and the pH of the source water elevated to a pH of 9.0, and preferably 9.6, or higher. With respect to the latter, the pH may be adjusted by the addition of an alkaline agent, such as sodium hydroxide, or by simply removing a portion of the aqueous system water through such well known techniques or processes as evaporation and/or distillation. In a related application, we have unexpectedly discovered that the excessive corrosion of carbon steel, copper, copper alloys, and stainless steel alloys in aqueous systems due to high ionic strength (electrolytic potential) contributed by high dissolved solids source water or highly cycled (10,000 to 150,000 μmhos non-neutralized conductivity) systems can likewise be controlled by the methods of the present inventions of the present invention. In such context, the methods of the present invention comprises removing hardness ions (calcium and magnesium) from the makeup source water using known pretreatment methods of the present inventions, such as ion exchange resins, selective ion removal with reverse osmosis, reverse osmosis, electrochemical removal, chemical precipitation, or evaporation/distillation. The pretreatment methods of the present invention will preferably maintain the total hardness ratio in the makeup water at less than 20%, and preferably at least less than 5%, of the makeup silica residual (mg/L SiO 2 ), as determined from an initial analysis of the source water. When source makeup water is naturally soft, with less than 10 mg/L hardness as CaCO 3 , pretreatment removal of hardness ions may be bypassed in some systems. Thereafter, the conductivity (non-neutralized) in the aqueous system is controlled such that the same is maintained between 10,000 and 150,000, and more preferably 20,000 to 150,000, μmhos. Alkalinity is then controlled as quantified by pH at 9.0 or higher, with a pH of 9.6 being more highly desired in some applications. Control of soluble silica at a minimum residual concentration of 200 mg/L as SiO 2 to support corrosion inhibition. With respect to the latter, the SiO 2 may be adjusted by the addition of a silica/silicate agent, such as sodium silicate, or by simply removing a portion of the aqueous system water through such well known techniques or processes as evaporation and/or distillation. detailed-description description="Detailed Description" end="lead"? | 20040109 | 20050816 | 20050714 | 63101.0 | 1 | HRUSKOCI, PETER A | COOLING WATER SCALE AND CORROSION INHIBITION | SMALL | 0 | ACCEPTED | 2,004 |
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10,754,899 | ACCEPTED | System and methods for determining nerve proximity, direction, and pathology during surgery | The present invention involves systems and methods for determining nerve proximity, nerve direction, and pathology relative to a surgical instrument based on an identified relationship between neuromuscular responses and the stimulation signal that caused the neuromuscular responses. | 1. A surgical system, comprising: a control unit having at least one of computer programming software, firmware and hardware capable of delivering a stimulation signal, receiving and processing neuromuscular responses due to the stimulation signal, and identifying a relationship between the neuromuscular response and the stimulation signal; and a surgical instrument having at least one stimulation electrode electrically coupled to said control unit for transmitting the stimulation signal, wherein said control unit is capable of determining at least one of nerve proximity, nerve direction, and nerve pathology relative to the surgical instrument based on the identified relationship between the neuromuscular response and the stimulation signal. 2. The surgical system of claim 1 and further, wherein said control unit is further equipped to communicate at least one of alpha-numeric and graphical information to a user regarding at least one of nerve proximity, nerve direction, and nerve pathology. 3. The surgical system of claim 1 and further, wherein the surgical instrument may comprise at least one of a device for maintaining contact with a nerve during surgery, a device for accessing a surgical target site, and a device for testing screw placement integrity. 4. The surgical system of claim 1 and further, wherein the surgical instrument comprises a nerve root retractor and wherein the control unit determines nerve pathology based on the identified relationship between the neuromuscular response and the stimulation signal. 5. The surgical system of claim 1 and further, wherein the surgical instrument comprises a dilating instrument and wherein the control unit determines at least one of proximity and direction between a nerve and the instrument based on the identified relationship between the neuromuscular response and the stimulation signal. 6. The surgical system of claim 5 and further, wherein the dilating instrument comprises at least one of a K-wire, an obturator, a dilating cannula, and a working cannula. 7. The surgical system of claim 1 and further, wherein the surgical instrument comprises a screw test probe and wherein the control unit determines the proximity between the screw test probe and an exiting spinal nerve root to assess whether a medial wall of a pedicle has been breached by at least one of hole formation and screw placement. 8. A system comprising: an instrument with an electrode configured to transmit electrical current signals with adjustable amplitudes to a tissue; a sensor configured to detect a voltage response from a muscle; and a control unit coupled to the instrument and the sensor, the control unit being configured to (a) command the electrode to transmit electrical current signals with adjustable amplitudes, (b) receive a voltage response from the sensor, and (c) determine a threshold stimulation current for a predetermined threshold voltage response value, the threshold stimulation current corresponding to a distance between the electrode and a nerve associated with the muscle. 9. The system of claim 8, wherein the control unit is configured to determine a peak-to-peak amplitude of the voltage response and derive a threshold response voltage vs. stimulation current recruitment curve to determine a proximity of a nerve to the electrode. 10. The system of claim 8, wherein the control unit comprises a display configured to display the determined threshold stimulation current. 11. The system of claim 8, wherein the control unit comprises a display configured to display a response voltage vs. stimulation current recruitment curve. 12. The system of claim 8, wherein the control unit comprises a display configured to display an advance icon to a user when the determined threshold stimulation current is above a predetermined level. 13. The system of claim 8, wherein the control unit comprises a display configured to display a hold icon to a user when the determined threshold stimulation current is below a predetermined level. 14. The system of claim 8, wherein the control unit is configured to send a signal to the electrode to generate monophase current pulses with a predetermined duration. 15. The system of claim 8, wherein the control unit is configured to cause the electrode to generate monophase current pulses with a configurable duration. 16. The system of claim 8, wherein the control unit comprises an audio output configured to emit an audible sound to a user, the sound indicating a distance between the electrode and a nerve associated with the muscle. 17. The system of claim 8, wherein the sensor comprises a plurality of electrodes configured to sense electromyographic (EMG) voltage responses from a plurality of muscle groups. 18. The system of claim 8, wherein the instrument comprises a plurality of cannulae with different diameters, each cannula having at least one electrode. 19. The system of claim 8, wherein the instrument comprises a reusable component configured to be inserted through a cannula to a surgical site within a body. 20. The system of claim 8, wherein the instrument comprises a disposable portion. 21. The system of claim 8, wherein the instrument comprises a pedicle screw hole probe. 22. A system comprising: an instrument with a plurality of electrodes, each electrode being configured to transmit electrical current signals with adjustable amplitudes to a tissue; a sensor configured to detect voltage responses from a muscle; and a control unit coupled to the instrument and the sensor, the control unit being configured to (a) control the electrodes to transmit electrical current signals with adjustable amplitudes, (b) receive voltage responses from the sensor, and (c) for each electrode, determine a threshold stimulation current for a predetermined threshold voltage response value, the threshold stimulation currents of the electrodes corresponding to a direction with respect to the electrodes to a nerve associated with the muscle. 23. The system of claim 22, wherein the electrodes comprises four electrodes spaced orthogonally in a two-dimensional plane. 24. The system of claim 22, wherein the control unit is configured to determine a two-dimensional vector from a reference point of the instrument to a nerve by using: x = 1 - 4 R ( d 1 2 - d 3 2 ) and y = 1 - 4 R ( d 2 2 - d 4 2 ) . 25. The system of claim 22, wherein the sensor comprises a plurality of electrodes configured to sense electromyographic (EMG) voltage responses from a plurality of muscle groups. 26. The system of claim 22, wherein the control unit is configured to display the direction of the nerve in the tissue associated with the muscle with respect to the electrodes. 27. An instrument configured to be partially inserted through tissue, the instrument having a plurality of electrodes near a distal end of the instrument, each electrode being configured to generate an electrical current to the tissue, wherein the electrical current stimulates a nerve in the tissue if the instrument is sufficiently close to the nerve. 28. The instrument of claim 27, wherein the instrument comprises a shaft and four electrodes in a two-dimensional plane. 29. The instrument of claim 28, wherein the four electrodes are orthogonal. 30. A system comprising: an instrument with an electrode configured to transmit electrical current signals with adjustable amplitudes to a nerve; a sensor configured to detect voltage responses from a muscle associated with the nerve; and a control unit coupled to the instrument and the sensor, the control unit being configured to (a) control the electrode to transmit electrical current signals with adjustable amplitudes, (b) receive voltage responses from the sensor, and (c) determine a pathology of the nerve associated with the muscle by determining a relationship between a stimulation current and a voltage response. 31. The system of claim 30, wherein the relationship includes at least one of a threshold voltage response and threshold stimulation current. 32. The system of claim 30, wherein the relationship includes a ratio of the stimulation current and the corresponding voltage response. 33. The system of claim 30, wherein the relationship includes at least one of a saturation voltage response and a saturation stimulation current. 34. The system of claim 30, wherein the sensor comprises a plurality of electrodes configured to sense electromyographic (EMG) voltage responses from a plurality of muscle groups. 35. The system of claim 30, wherein the control unit comprises an audio output configured to emit an audible sound indicating a voltage response. 36. The system of claim 30, wherein the instrument comprises a nerve root retractor with a curved distal region. 37. A computer configured to (a) receive a plurality of voltage response signals, each voltage response value corresponding in time to a stimulation current signal with a configurable amplitude, and (b) determine a nerve stimulation current for a pre-determined voltage response value. 38. The computer of claim 37, being further configured to command an instrument to transmit the stimulation current signals. 39. The computer of claim 37, being configured to determine a peak-to-peak amplitude for each voltage response signal. 40. The computer of claim 37, being configured to store a first time duration from a stimulation current signal to a first peak of a voltage response. 41. The computer of claim 40, being configured to store a second time duration from the stimulation current signal to a second peak of the voltage response. 42. The computer of claim 41, being configured to store a plurality of first and second time durations as a plurality of stimulation current signals are generated and a plurality of voltage response values are received, the processing unit using the plurality of first and second time durations to perform artifact rejection. 43. The computer of claim 37, being configured to execute a bracketing process with a plurality of pre-determined stimulation current levels to determine the stimulation current for the pre-determined voltage response value. 44. The computer of claim 37, being configured to execute a bisecting process with a plurality of pre-determined stimulation current levels to determine the stimulation current for the pre-determined voltage response value. 45. The computer of claim 37, being further configured to communicate the determined stimulation current for the predetermined threshold voltage response value to a user. 46. The computer of claim 37, being further configured to control a display unit configured to display the stimulation current for the pre-determined voltage response value. 47. The computer of claim 37, being further configured to receive user commands. 48. The computer of claim 37, further comprising a touch screen display configured to receive instructions from a user. 49. The computer of claim 37, being configured to receive a plurality of voltage response signals from a plurality of sensors located at various locations of a body. 50. The computer of claim 49, being configured to execute a time-multiplexing process to determine the stimulation current of each sensor for the pre-determined voltage response value. 51. A software application stored in a medium and executable by processor, the software application being configured to (a) receive a plurality of voltage response values and (b) bracket a threshold nerve stimulation current value corresponding to a predetermined threshold voltage response value. 52. The software application of claim 51, being configured to bisect a bracket that includes the threshold nerve stimulation current value corresponding to the predetermined threshold voltage response value. 53. The software application of claim 51, being configured to receive user commands. 54. The software application of claim 51, being configured to activate a nerve proximity determination mode. 55. The software application of claim 51, being configured to activate a nerve direction determination mode. 56. The software application of claim 51, being configured to activate a nerve pathology determination mode. 57. The software application of claim 51, comprising a graphical user interface configured to display a bracketed threshold nerve stimulation current value. 58. The software application of claim 51, comprising a graphical user interface configured to display a name of an instrument being used to deliver a plurality of electrical current signals. 59. The software application of claim 51, comprising a graphical user interface configured to display a symbol of an instrument being used to deliver a plurality of electrical current signals. 60. The software application of claim 51, comprising a graphical user interface configured to display locations of nerves and muscles. 61. The software application of claim 51, comprising a graphical user interface configured to display locations of a plurality of sensors. 62. The software application of claim 51, comprising a graphical user interface configured to display a color that indicates a determined threshold stimulation current value. 63. The software application of claim 51, configured to determine a maximum frequency of stimulation current pulses. 64. A software application stored in a medium and executable by processor, the software application being configured to adjust a frequency and an amplitude of a stimulation electrical current generated by an electrode on an instrument, the electrical current stimulating a nerve when the instrument is placed within a range of the nerve. 65. A module comprising: an output connector configured to output a signal to an instrument to generate a stimulation electrical current to a tissue; a plurality of input connectors configured to receive a plurality of voltage signals from a plurality of sensors in response to the stimulation current; signal conditioning circuitry configured to convert the voltage signals to digital signals; and a second output connector configured to output digital signals to a control unit. 66. The module of claim 65, further comprising a stimulator drive and steering circuitry. 67. The module of claim 65, further comprising a digital communications interface. 68. A surgical device with a plurality of electrodes along a longitudinal surface of the device, each electrode operable to generate an electrical stimulation current to a tissue proximate to the electrode, if the tissue comprises a nerve within range of an electrode, the current causes an electromyographic (EMG) response in a muscle associated with the nerve. 69. The surgical device of claim 68, comprising a cannula. 70. The surgical device of claim 68, comprising a nerve root retractor. 71. A system comprising: a pedicle screw test probe having at least one electrode, the electrode being configured to deliver an electrical current signal to a hole sized to fit a pedicle screw; a sensor configured to sense a voltage response from a muscle caused by the electrical current signal; and a control unit configured to compare the electrical current signal and the voltage response to determine if the pedicle hole has been breached. 72. The system of claim 71, wherein the pedicle screw test probe has a ball-tipped distal end. 73. A device configured to simulate a nerve and muscle in a patient, the device comprising: a input connector configured to receive electrical current stimulation signals with a plurality of amplitude levels from an instrument; a processing unit configured to derive pre-determined voltage response signals in response to the electrical current stimulation signals; and an output connector configured to output voltage response signals in response to the electrical current stimulation signals. 74. A method of providing a nerve stimulation system, the method comprises: providing a control unit; and loading software in the control unit, the software being configured to initiate a stimulation current signal upon receiving a user command, monitor a voltage response signal after initiating the stimulation current signal, and determine a stimulation current for a pre-determined voltage response value. 75. The method of claim 74, further comprising setting a threshold voltage response value. 76. The method of claim 74, further comprising configuring a maximum stimulation current. 77. A method comprising: delivering a plurality of electrical current signals near a tissue region; sensing a plurality of electromyographic (EMG) voltage responses of a muscle associated with a nerve in the tissue region; and identifying a relationship between amplitudes of the current signals and the EMG voltage responses. 78. The method of claim 77, further comprising determining a stimulation current for a predetermined threshold voltage response. 79. The method of claim 77, wherein identifying a relationship comprises bracketing a threshold stimulation current. 80. The method of claim 77, wherein identifying a relationship comprises bisecting a bracket containing a threshold stimulation current. 81. The method of claim 77, further comprising inserting an instrument with an electrode through tissue near a spine. 82. The method of claim 77, further comprising establishing an operative corridor through tissues having neural structure. 83. The method of claim 77, further comprising advancing a cannula toward a target site. 84. The method of claim 77, wherein the target site is an annulus of an intervertebral disc. 85. The method of claim 77, further comprising determining a threshold current by linear regression. 86. The method of claim 77, further comprising a dynamic sweep subtraction process. 87. The method of claim 77, further comprising displaying a decreasing threshold stimulation current as a stimulation electrode moves closer to a nerve. 88. The method of claim 77, further comprising displaying a name of an instrument being used to deliver the plurality of electrical current signals. 89. The method of claim 77, further comprising displaying locations of sensors sensing a plurality of electromyographic (EMG) voltage responses of muscles. 90. The method of claim 77, further comprising notifying a user to advance a surgical instrument delivering the plurality of electrical current signals. 91. The method of claim 77, further comprising notifying a user to hold a surgical instrument delivering the plurality of electrical current signals. 92. The method of claim 77, further comprising notifying a user when a nerve is impinged. 93. The method of claim 77, further comprising determining peak-to-peak voltage values of the EMG voltage responses of a muscle myotome in response to the plurality of electrical current signals applied to a nerve. 94. The method of claim 77, further comprising delivering electrical current signals as monophase pulses with a predetermined duration and configurable amplitudes. 95. The method of claim 77, further comprising delivering electrical current signals as monophase pulses with configurable durations and amplitudes. 96. The method of claim 77, further comprising displaying a voltage response vs. stimulation current recruitment curve. 97. The method of claim 77, further comprising measuring a first time duration from a stimulation current pulse to a first peak of a voltage response waveform. 98. The method of claim 97, further comprising measuring a second time duration from a stimulation current pulse to a second peak of a voltage response waveform. 99. The method of claim 98, further comprising collecting multiple samples of the first and second time durations. 100. The method of claim 98, further comprising compiling the first and second time durations in a histogram. 101. The method of claim 77, further comprising displaying a direction of a nerve based on the relationship between amplitudes of the current signals and the EMG voltage responses. 102. The method of claim 77, further comprising displaying a pathology of a nerve based on the relationship between amplitudes of the current signals and the EMG voltage responses. 103. The method of claim 77, further comprising retracting the nerve. 104. The method of claim 77, further comprising displaying a function of the nerve in real-time as a surgical instrument is moved with respect to the nerve. 105. The method of claim 77, further comprising sensing and displaying a function of the nerve in real-time during a surgical procedure. 106. The method of claim 77, further comprising testing a pedicle hole. 107. The method of claim 77, further comprising testing a screw in a pedicle hole. 108. The method of claim 77, further comprising determining whether a pedicle wall has been breached by the screw. 109. The method of claim 77, further comprising displaying a channel with a lowest response among a plurality of channels. 110. The method of claim 77, further comprising concurrently displaying voltage waveforms of a plurality of electromyographic (EMG) responses from a plurality of sensors. | CROSS-REFERENCES TO RELATED APPLICATIONS The present application is a regular patent application of and claims the benefit of priority from U.S. Provisional Patent Application Ser. No. 60/305,041, filed Jul. 11, 2001 and assigned to the Assignee hereof, the entire contents of which is hereby expressly incorporated by reference into this disclosure as if set forth fully herein. BACKGROUND OF THE INVENTION I. Field of the Invention This invention relates to nerve monitoring systems and to nerve muscle monitoring systems, and more particularly to systems and methods for determining nerve proximity, nerve direction, and pathology during surgery. II. Description of Related Art Systems and methods exist for monitoring nerves and nerve muscles. One such system determines when a needle is approaching a nerve. The system applies a current to the needle to evoke a muscular response. The muscular response is visually monitored, typically as a shake or “twitch.” When such a muscular response is observed by the user, the needle is considered to be near the nerve coupled to the responsive muscle. These systems require the user to observe the muscular response (to determine that the needle has approached the nerve). This may be difficult depending on the competing tasks of the user. In addition, when general anesthesia is used during a procedure, muscular response may be suppressed, limiting the ability of a user to detect the response. While generally effective (although crude) in determining nerve proximity, such existing systems are incapable of determining the direction of the nerve to the needle or instrument passing through tissue or passing by the nerves. This can be disadvantageous in that, while the surgeon may appreciate that a nerve is in the general proximity of the instrument, the inability to determine the direction of the nerve relative to the instrument can lead to guess work by the surgeon in advancing the instrument and thereby raise the specter of inadvertent contact with, and possible damage to, the nerve. Another nerve-related issue in existing surgical applications involves the use of nerve retractors. A typical nerve retractor serves to pull or otherwise maintain the nerve outside the area of surgery, thereby protecting the nerve from inadvertent damage or contact by the “active” instrumentation used to perform the actual surgery. While generally advantageous in protecting the nerve, it has been observed that such retraction can cause nerve function to become impaired or otherwise pathologic over time due to the retraction. In certain surgical applications, such as spinal surgery, it is not possible to determine if such retraction is hurting or damaging the retracted nerve until after the surgery (generally referred to as a change in “nerve health” or “nerve status”). There are also no known techniques or systems for assessing whether a given procedure is having a beneficial effect on a nerve or nerve root known to be pathologic (that is, impaired or otherwise unhealthy). Based on the foregoing, a need exists for a better system and method that can determine the proximity of a surgical instrument (including but not limited to a needle, catheter, cannula, probe, or any other device capable of traversing through tissue or passing near nerves or nerve structures) to a nerve or group of nerves during surgery. A need also exists for a system and method for determining the direction of the nerve relative to the surgical instrument. A still further need exists for a manner of monitoring nerve health or status during surgical procedures. The present invention is directed at eliminating, or at least reducing the effects of, the above-described problems with the prior art, as well as addressing the above-identified needs. SUMMARY OF THE INVENTION The present invention includes a system and related methods for determining nerve proximity and nerve direction to surgical instruments employed in accessing a surgical target site, as well as monitoring the status or health (pathology) of a nerve or nerve root during surgical procedures. According to a broad aspect, the present invention includes a surgical system, comprising a control unit and a surgical instrument. The control unit has at least one of computer programming software, firmware and hardware capable of delivering a stimulation signal, receiving and processing neuromuscular responses due to the stimulation signal, and identifying a relationship between the neuromuscular response and the stimulation signal. The surgical instrument has at least one stimulation electrode electrically coupled to said control unit for transmitting the stimulation signal, wherein said control unit is capable of determining at least one of nerve proximity, nerve direction, and nerve pathology relative to the surgical instrument based on the identified relationship between the neuromuscular response and the stimulation signal. In a further embodiment of the surgical system of the present invention, the control unit is further equipped to communicate at least one of alpha-numeric and graphical information to a user regarding at least one of nerve proximity, nerve direction, and nerve pathology. In a further embodiment of the surgical system of the present invention, the surgical instrument may comprise at least one of a device for maintaining contact with a nerve during surgery, a device for accessing a surgical target site, and a device for testing screw placement integrity. In a further embodiment of the surgical system of the present invention, the surgical instrument comprises a nerve root retractor and wherein the control unit determines nerve pathology based on the identified relationship between the neuromuscular response and the stimulation signal. In a further embodiment of the surgical system of the present invention, the surgical instrument comprises a dilating instrument and wherein the control unit determines at least one of proximity and direction between a nerve and the instrument based on the identified relationship between the neuromuscular response and the stimulation signal. In a further embodiment of the surgical system of the present invention, the dilating instrument comprises at least one of a K-wire, an obturator, a dilating cannula, and a working cannula. In a further embodiment of the surgical system of the present invention, the surgical instrument comprises a screw test probe and wherein the control unit determines the proximity between the screw test probe and an exiting spinal nerve root to assess whether a medial wall of a pedicle has been breached by at least one of hole formation and screw placement. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a surgical system 10 capable of determining, among other things, nerve proximity, direction, and pathology according to one aspect of the present invention; FIG. 2 is a block diagram of the surgical system 10 shown in FIG. 1; FIG. 3 is a graph illustrating a plot of the neuromuscular response (EMG) of a given myotome over time based on a current stimulation pulse (similar to that shown in FIG. 4) applied to a nerve bundle coupled to the given myotome; FIG. 4 is a graph illustrating a plot of a stimulation current pulse capable of producing a neuromuscular response (EMG) of the type shown in FIG. 3; FIG. 5 is a graph illustrating a plot of peak-to-peak voltage (Vpp) for each given stimulation current level (IStim) forming a stimulation current pulse train according to the present invention (otherwise known as a “recruitment curve”); FIG. 6 is a graph illustrating a plot of a neuromuscular response (EMG) over time (in response to a stimulus current pulse) showing the manner in which maximum voltage (VMax) and minimum voltage (VMin) occur at times T1 and T2, respectively; FIG. 7 is an exemplary touch-screen display according to the present invention, capable of communicating a host of alpha-numeric and/or graphical information to a user and receiving information and/or instructions from the user during the operation of the surgical system 10 of FIG. 1; FIGS. 8A-8E are graphs illustrating a rapid current threshold-hunting algorithm according to one embodiment of the present invention; FIG. 9 is a series of graphs illustrating a multi-channel rapid current threshold-hunting algorithm according to one embodiment of the present invention; FIG. 10 is a graph illustrating a T1, T2 artifact rejection technique according to one embodiment of the present invention via the use of histograms; FIG. 11 is a graph illustrating the proportion of stimulations versus the number of stimulations employed in the T1, T2 artifact rejection technique according to the present invention; FIG. 12 is an illustration (graphical and schematic) of a method of automatically determining the maximum frequency (FMax) of the stimulation current pulses according to one embodiment of the present invention; FIG. 13 is a graph illustrating a method of determining the direction of a nerve (denoted as an “octagon”) relative to an instrument having four (4) orthogonally disposed stimulation electrodes (denoted by the “circles”) according to one embodiment of the present invention; FIG. 14 is a graph illustrating recruitment curves for a generally healthy nerve (denoted “A”) and a generally unhealthy nerve (denoted “B”) according to the nerve pathology determination method of the present invention; FIG. 15 is flow chart illustrating an alternate method of determining the hanging point of a recruitment curve according to an embodiment of the present invention; and FIG. 16 is a graph illustrating a simulated recruitment curve generated by a “virtual patient” device and method according to the present invention. DESCRIPTION OF THE SPECIFIC EMBODIMENTS Illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. The systems disclosed herein boast a variety of inventive features and components that warrant patent protection, both individually and in combination. FIG. 1 illustrates, by way of example only, a surgical system 10 capable of employing the nerve proximity, nerve direction, and nerve pathology assessments according to the present invention. As will be explained in greater detail below, the surgical system 10 is capable of providing safe and reproducible access to any number of surgical target sites, as well as monitoring changes in nerve pathology (health or status) during surgical procedures. It is expressly noted that, although described herein largely in terms of use in spinal surgery, the surgical system 10 and related methods of the present invention are suitable for use in any number of additional surgical procedures wherein tissue having significant neural structures must be passed through (or near) in order to establish an operative corridor, or where neural structures are retracted. The surgical system 10 includes a control unit 12, a patient module 14, an EMG harness 16 and return electrode 35 coupled to the patient module 14, and a host of surgical accessories 20 capable of being coupled to the patient module 14 via one or more accessory cables 22. The surgical accessories 20 may include, but are not necessarily limited to, surgical access components (such as a K-wire 24, one or more dilating cannula 26, and a working cannula 28), neural pathology monitoring devices (such as nerve root retractor 30), and devices for performing pedicle screw test (such as screw test probe 32). A block diagram of the surgical system 10 is shown in FIG. 2, the operation of which is readily apparent in view of the following description. The control unit 12 includes a touch screen display 36 and a base 38. The touch screen display 36 is preferably equipped with a graphical user interface (GUI) capable of communicating information to the user and receiving instructions from the user. The base 38 contains computer hardware and software that commands the stimulation sources, receives digitized signals and other information from the patient module 14, and processes the EMG responses to extract characteristic information for each muscle group, and displays the processed data to the operator via the display 36. The primary functions of the software within the control unit 12 include receiving user commands via the touch screen display 36, activating stimulation in the requested mode (nerve proximity, nerve direction, nerve pathology, screw test), processing signal data according to defined algorithms (described below), displaying received parameters and processed data, and monitoring system status and report fault conditions. The patient module 14 is connected via a serial cable 40 to the control unit 12, and contains the electrical connections to all electrodes, signal conditioning circuitry, stimulator drive and steering circuitry, and a digital communications interface to the control unit 12. In use, the control unit 12 is situated outside but close to the surgical field (such as on a cart adjacent the operating table) such that the display 36 is directed towards the surgeon for easy visualization. The patient module 14 should be located between the patient's legs, or may be affixed to the end of the operating table at mid-leg level using a bedrail clamp. The position selected should be such that the EMG leads can reach their farthest desired location without tension during the surgical procedure. In a significant aspect of the present invention, the information displayed to the user on display 36 may include, but is not necessarily limited to, alpha-numeric and/or graphical information regarding nerve proximity, nerve direction, nerve pathology, stimulation level, myotome/EMG levels, screw testing, advance or hold instructions, and the instrument in use. In one embodiment (set forth by way of example only) the display includes the following components as set forth in Table 1: TABLE 1 Screen Component Description Menu/Status Bar The mode label may include the surgical accessory attached, such as the surgical access components (K-Wire, Dilating Cannula, Working Cannula), nerve pathology monitoring device (Nerve Root Retractor), and/or screw test device (Screw Test Probe) depending on which is attached. Spine Image An image of a human body/skeleton showing the electrode placement on the body, with labeled channel number tabs on each side (1-4 on left and right). Left and Right labels will show the patient orientation. The Channel number tabs may be highlighted or colored depending on the specific function being performed. Display Area Shows procedure-specific information. Myotome & Level A label to indicate the Myotome name and Names corresponding Spinal Level(s) associated with the channel of interest. Advance/Hold When in the Detection mode, an indication of “Advance” will show when it is safe to move the cannula forward (such as when the minimum stimulation current threshold IThresh (described below) is greater than a predetermined value, indicating a safe distance to the nerve) and “Hold” will show when it is unsafe to advance the cannula (such as when the minimum stimulation current threshold IThresh (described below) is less than a predetermined value, indicating that the nerve is relatively close to the cannula) and during proximity calculations. Function Indicates which function is currently active (Direction, Detection, Pathology Monitoring, Screw Test). Dilator In Use A colored circle to indicate the inner diameter of the cannula, with the numeric size. If cannula is detached, no indicator is displayed. The surgical system 10 accomplishes safe and reproducible access to a surgical target site by detecting the existence of (and optionally the distance and/or direction to) neural structures before, during, and after the establishment of an operative corridor through (or near) any of a variety of tissues having such neural structures which, if contacted or impinged, may otherwise result in neural impairment for the patient. The surgical system 10 does so by electrically stimulating nerves via one or more stimulation electrodes at the distal end of the surgical access components 24-28 while monitoring the EMG responses of the muscle groups innervated by the nerves. In a preferred embodiment, this is accomplished via 8 pairs of EMG electrodes 34 placed on the skin over the major muscle groups on the legs (four per side), an anode electrode 35 providing a return path for the stimulation current, and a common electrode 37 providing a ground reference to pre-amplifiers in the patient module 14. By way of example, the placement of EMG electrodes 34 may be undertaken according to the manner shown in Table 2 below for spinal surgery: TABLE 2 Channel Color ID Myotome Nerve Spinal Level Red Right 1 Right Vastus Medialis Femoral L2, L3, L4 Orange Right 2 Right TibialisAnterior Peroneal L4, L5 Yellow Right 3 Right Biceps Femoris Sciatic L5, S1, S2 Green Right 4 Right Gastroc. Medial Post Tibialis S1, S2 Blue Left 1 Left Vastus Medialis Femoral L2, L3, L4 Violet Left 2 Left Tibialis Anterior Peroneal L4, L5 Gray Left 3 Left Biceps Femoris Sciatic L5, S1, S2 White Left 4 Left Gastroc. Medial Post Tibialis S1, S2 Although not shown, it will be appreciated that any of a variety of electrodes can be employed, including but not limited to needle electrodes. The EMG responses provide a quantitative measure of the nerve depolarization caused by the electrical stimulus. Analysis of the EMG responses is then used to determine the proximity and direction of the nerve to the stimulation electrode, as will be described with particularity below. The surgical access components 24-28 are designed to bluntly dissect the tissue between the patient's skin and the surgical target site. An initial dilating cannula 26 is advanced towards the target site, preferably after having been aligned using any number of commercially available surgical guide frames. An obturator (not shown) may be included inside the initial dilator 26 and may similarly be equipped with one or more stimulating electrodes. Once the proper location is achieved, the obturator (not shown) may be removed and the K-wire 24 inserted down the center of the initial dilating cannula 26 and docked to the given surgical target site, such as the annulus of an intervertebral disc. Cannulae of increasing diameter are then guided over the previously installed cannula 26 until the desired lumen is installed. By way of example only, the dilating cannulae 26 may range in diameter from 6 mm to 30 mm. In one embodiment, each cannula 26 has four orthogonal stimulating electrodes at the tip to allow detection and direction evaluation, as will be described below. The working cannula 28 is installed over the last dilating cannula 26 and then all the dilating cannulae 26 are removed from inside the inner lumen of the working cannula 28 to establish the operative corridor therethrough. A stimulator driver 42 is provided to electrically couple the particular surgical access component 24-28 to the patient module 14 (via accessory cable 22). In a preferred embodiment, the stimulator driver 42 includes one or more buttons for selectively activating the stimulation current and/or directing it to a particular surgical access component. The surgical system 10 accomplishes neural pathology monitoring by electrically stimulating a retracted nerve root via one or more stimulation electrodes at the distal end of the nerve root retractor 30 while monitoring the EMG responses of the muscle group innervated by the particular nerve. The EMG responses provide a quantitative measure of the nerve depolarization caused by the electrical stimulus. Analysis of the EMG responses may then be used to assess the degree to which retraction of a nerve or neural structure affects the nerve function over time, as will be described with greater particularity below. One advantage of such monitoring, by way of example only, is that the conduction of the nerve may be monitored during the procedure to determine whether the neurophysiology and/or function of the nerve changes (for the better or worse) as the result of the particular surgical procedure. For example, it may be observed that the nerve conduction increases as the result of the operation, indicating that the previously inhibited nerve has been positively affected by the operation. The nerve root retractor 30 may comprise any number of suitable devices capable of maintaining contact with a nerve or nerve root. The nerve root retractor 30 may be dimensioned in any number of different fashions, including having a generally curved distal region (shown as a side view in FIG. 1 to illustrate the concave region where the nerve will be positioned while retracted), and of sufficient dimension (width and/or length) and rigidity to maintain the retracted nerve in a desired position during surgery. The nerve root retractor 30 may also be equipped with a handle 31 having one or more buttons for selectively applying the electrical stimulation to the stimulation electrode(s) at the end of the nerve root retractor 30. In one embodiment, the nerve root retractor 30 is disposable and the handle 31 is reusable and autoclavable. The surgical system 10 can also be employed to perform screw test assessments via the use of screw test probe 32. The screw test probe 32 is used to test the integrity of pedicle holes (after formation) and/or screws (after introduction). The screw test probe 32 includes a handle 44 and a probe member 46 having a generally ball-tipped end 48. The handle 44 may be equipped with one or more buttons for selectively applying the electrical stimulation to the ball-tipped end 48 at the end of the probe member 46. The ball tip 48 of the screw test probe 32 is placed in the screw hole prior to screw insertion or placed on the installed screw head. If the pedicle wall has been breached by the screw or tap, the stimulation current will pass through to the adjacent nerve roots and they will depolarize at a lower stimulation current. Upon pressing the button on the screw test handle 44, the software will execute an algorithm that results in all channel tabs being color-coded to indicate the detection status of the corresponding nerve. The channel with the “worst” (lowest) level will be highlighted (enlarged) and that myotome name will be displayed, as well as graphically depicted on the spine diagram. A vertical bar chart will also be shown, to depict the stimulation current required for nerve depolarization in mA for the selected channel. The screw test algorithm preferably determines the depolarization (threshold) current for all 8 EMG channels. The surgeon may also set a baseline threshold current by stimulating a nerve root directly with the screw test probe 32. The surgeon may choose to display the screw test threshold current relative to this baseline. The handle 44 may be equipped with a mechanism (via hardware and/or software) to identify itself to the system when it is attached. In one embodiment, the probe member 46 is disposable and the handle 44 is reusable and autoclavable. An audio pick-up (not shown) may also be provided as an optional feature according to the present invention. In some cases, when a nerve is stretched or compressed, it will emit a burst or train of spontaneous nerve activity. The audio pick-up is capable of transmitting sounds representative of such activity such that the surgeon can monitor this response on audio to help him determine if there has been stress to the nerve. Analysis of the EMG responses according to the present invention will now be described. The nerve proximity, nerve direction, and nerve pathology features of the present invention are based on assessing the evoked response of the various muscle myotomes monitored by the surgical system 10. This is best shown in FIGS. 3-4, wherein FIG. 3 illustrates the evoked response (EMG) of a monitored myotome to the stimulation current pulse shown in FIG. 4. The EMG response can be characterized by a peak to peak voltage of Vpp=Vmax−Vmin. The stimulation current is preferably DC coupled and comprised of monophasic pulses of 200 microsecond duration with frequency and amplitude that is adjusted by the software. For each nerve and myotome there is a characteristic delay from the stimulation current pulse to the EMG response. As shown in FIG. 5, there is a threshold stimulation current required to depolarize the main nerve trunk. Below this threshold, current stimulation does not evoke a significant Vpp response. Once the stimulation threshold is reached, the evoked response is reproducible and increases with increasing stimulation, as shown in FIG. 5. This is known as a “recruitment curve.” In one embodiment, a significant Vpp is defined to be a minimum of 100 uV. The lowest stimulation current that evoked this threshold voltage is called Ithresh. Ithresh decreases as the stimulation electrode approaches the nerve. This value is useful to surgeons because it provides a relative indication of distance (proximity) from the electrode to the nerve. As shown in FIG. 6, for each nerve/myotome combination there is a characteristic delay from the stimulation current pulse to the EMG response. For each stimulation current pulse, the time from the current pulse to the first max/min is T1 and to the second max/min is T2. The first phase of the pulse may be positive or negative. As will be described below, the values of T1, T2 are each compiled into a histogram with bins as wide as the sampling rate. New values of T1, T2 are acquired with each stimulation and the histograms are continuously updated. The value of T1 and T2 used is the center value of the largest bin in the histogram. The values of T1, T2 are continuously updated as the histograms change. Initially Vpp is acquired using a window that contains the entire EMG response. After 20 samples, the use of T1, T2 windows is phased in over a period of 200 samples. Vmax and Vmin are then acquired only during windows centered around T1, T2 with widths of, by way of example only, 5 msec. This method of acquiring Vpp is advantageous in that it automatically performs artifact rejection (as will be described in greater detail below). As will be explained in greater detail below, the use of the “recruitment curve” according to the present invention is advantageous in that it provides a great amount of useful data from which to make various assessments (including, but not limited to, nerve detection, nerve direction, and nerve pathology monitoring). Moreover, it provides the ability to present simplified yet meaningful data to the user, as opposed to the actual EMG waveforms that are displayed to the users in traditional EMG systems. Due to the complexity in interpreting EMG waveforms, such prior art systems typically require an additional person specifically trained in such matters. This, in turn, can be disadvantageous in that it translates into extra expense (having yet another highly trained person in attendance) and oftentimes presents scheduling challenges because most hospitals do not retain such personnel. To account for the possibility that certain individuals will want to see the actual EMG waveforms, the surgical system 10 includes an Evoked Potentials display that shows the voltage waveform for all 8 EMG channels in real time. It shows the response of each monitored myotome to a current stimulation pulse. The display is updated each time there is a stimulation pulse. The Evoked Potentials display may be accessed during Detection, Direction, or Nerve Pathology Monitoring. Nerve Detection (Proximity) The Nerve Detection function of the present invention is used to detect a nerve with a stimulation electrode (i.e. those found on the surgical access components 24-28) and to give the user a relative indication of the proximity of the nerve to the electrode as it is advanced toward the surgical target site. A method of nerve proximity detection according one embodiment of the present invention is summarized as follows: (1) stimulation current pulses are emitted from the electrode with a fixed pulse width of 200 μs and a variable amplitude; (2) the EMG response of the associated muscle group is measured; (3) the Vpp of the EMG response is determined using T1, T2, and Fmax (NB: before T2 is determined, a constant Fsafe is used for Fmax); (4) a rapid hunting detection algorithm is used to determine IThresh for a known Vthresh minimum; (5) the value of It is displayed to the user as a relative indication of the proximity of the nerve, wherein the IThresh is expected to decrease as the probe gets closer to the nerve. A detailed description of the algorithms associated with the foregoing steps will follow after a general description of the manner in which this proximity information is communicated to the user. The Detection Function displays the value of Ithresh to the surgeon along with a color code so that the surgeon may use this information to avoid contact with neural tissues. This is shown generally in FIG. 7, which illustrates an exemplary screen display according to the present invention. Detection display is based on the amplitude of the current (Ithresh) required to evoke an EMG Vpp response greater than Vthresh (nominally 100 uV). According to one embodiment, if Ithresh is <=4 mA red is displayed, the absolute value of Ithresh is displayed. If 4 mA<Ithresh<10 mA yellow is displayed. If Ithresh>=10 mA green is displayed. Normally, Ithresh is only displayed when it is in the red range. However, the surgeon has the option of displaying Ithresh for all three ranges (red, yellow, green). The maximum stimulation current is preferably set by the user and is preferably within the range of between 0-100 mA. Detection is performed on all 4 channels of the selected side. EMG channels on the opposite side are not used. The first dilator 26 may use an obturator having an electrode for stimulation. In one embodiment, all subsequent dilators 26 and the working cannula 28 use four electrodes for stimulation. The lowest value of Ithresh from the 4 electrodes is used for display. There is an “Advance/Hold” display that tells the surgeon when the calculations are finished and he may continue to advance the instrument. The threshold-hunting algorithm employs a series of monopolar stimulations to determine the stimulation current threshold for each EMG channel that is in scope. The nerve is stimulated using current pulses with amplitude of Istim. The muscle groups respond with an evoked potential that has a peak to peak voltage of Vpp. The object of this algorithm is to quickly find Ithresh. This is the minimum Istim that results in a Vpp that is greater than a known threshold voltage Vthresh. The value of Istim is adjusted by a bracketing method as follows. The first bracket is 0.2 mA and 0.3 mA. If the Vpp corresponding to both of these stimulation currents is lower than Vthresh, then the bracket size is doubled to 0.2 mA and 0.4 mA. This exponential doubling of the bracket size continues until the upper end of the bracket results in a Vpp that is above Vthresh. The size of the brackets is then reduced by a bisection method. A current stimulation value at the midpoint of the bracket is used and if this results in a Vpp that is above Vthresh, then the lower half becomes the new bracket. Likewise, if the midpoint Vpp is below Vthresh then the upper half becomes the new bracket. This bisection method is used until the bracket size has been reduced to IThresh mA. IThresh is the value of Istim that is the higher end of the bracket. More specifically, with reference to FIGS. 8A-8E, the threshold hunting will support three states: bracketing, bisection, and monitoring. A stimulation current bracket is a range of stimulation currents that bracket the stimulation current threshold IThresh. The upper and/or lower boundaries of a bracket may be indeterminate. The width of a bracket is the upper boundary value minus the lower boundary value. If the stimulation current threshold IThresh of a channel exceeds the maximum stimulation current, that threshold is considered out-of-range. During the bracketing state, threshold hunting will employ the method below to select stimulation currents and identify stimulation current brackets for each EMG channel in scope. The method for finding the minimum stimulation current uses the methods of bracketing and bisection. The “root” is identified for a function that has the value −1 for stimulation currents that do not evoke adequate response; the function has the value +1 for stimulation currents that evoke a response. The root occurs when the function jumps from −1 to +1 as stimulation current is increased: the function never has the value of precisely zero. The root will not be known precisely, but only with some level of accuracy. The root is found by identifying a range that must contain the root. The upper bound of this range is the lowest stimulation current IThresh where the function returns the value +1, i.e. the minimum stimulation current that evokes VThresh response. The proximity function begins by adjusting the stimulation current until the root is bracketed (FIG. 8B). The initial bracketing range may be provided in any number of suitable ranges. In one embodiment, the initial bracketing range is 0.2 to 0.3 mA. If the upper stimulation current does not evoke a response, the upper end of the range should be increased. The range scale factor is 2. The stimulation current should never be increased by more than 10 mA in one iteration. The stimulation current should never exceed the programmed maximum stimulation current. For each stimulation, the algorithm will examine the response of each active channel to determine whether it falls within that bracket. Once the stimulation current threshold of each channel has been bracketed, the algorithm transitions to the bisection state. During the bisection state (FIGS. 8C and 8D), threshold hunting will employ the method described below to select stimulation currents and narrow the bracket to a width of 0.1 mA for each EMG channel with an in-range threshold. After the minimum stimulation current has been bracketed (FIG. 8B), the range containing the root is refined until the root is known with a specified accuracy. The bisection method is used to refine the range containing the root. In one embodiment, the root should be found to a precision of 0.1 mA. During the bisection method, the stimulation current at the midpoint of the bracket is used. If the stimulation evokes a response, the bracket shrinks to the lower half of the previous range. If the stimulation fails to evoke a response, the bracket shrinks to the upper half of the previous range. The proximity algorithm is locked on the electrode position when the response threshold is bracketed by stimulation currents separated by 0.1 mA. The process is repeated for each of the active channels until all thresholds are precisely known. At that time, the algorithm enters the monitoring state. During the monitoring state (FIG. 8E), threshold hunting will employ the method described below to select stimulation currents and identify whether stimulation current thresholds are changing. In the monitoring state, the stimulation current level is decremented or incremented by 0.1 mA, depending on the response of a specific channel. If the threshold has not changed then the lower end of the bracket should not evoke a response, while the upper end of the bracket should. If either of these conditions fail, the bracket is adjusted accordingly. The process is repeated for each of the active channels to continue to assure that each threshold is bracketed. If stimulations fail to evoke the expected response three times in a row, then the algorithm transitions back to the bracketing state in order to reestablish the bracket. When it is necessary to determine the stimulation current thresholds (It) for more than one channel, they will be obtained by time-multiplexing the threshold-hunting algorithm as shown in FIG. 9. During the bracketing state, the algorithm will start with a stimulation current bracket of 0.2 mA and increase the size of the bracket exponentially. With each bracket, the algorithm will measure the Vpp of all channels to determine which bracket they fall into. After this first pass, the algorithm will know which exponential bracket contains the It for each channel. Next, during the bisection state, the algorithm will start with the lowest exponential bracket that contains an It and bisect it until It is found within 0.1 mA. If there are more than one It within an exponential bracket, they will be separated out during the bisection process, and the one with the lowest value will be found first. During the monitoring state, the algorithm will monitor the upper and lower boundries of the brackets for each It, starting with the lowest. If the It for one or more channels is not found in it's bracket, then the algorithm goes back to the bracketing state to re-establish the bracket for those channels. The method of performing automatic artifact rejection according to the present invention will now be described. As noted above, acquiring Vpp according to the present invention (based on T1,T2 shown in FIG. 6) is advantageous in that, among other reasons, it automatically performs artifact rejection. The nerve is stimulated using a series of current pulses above the stimulation threshold. The muscle groups respond with an evoked potential that has a peak to peak voltage of Vpp. For each EMG response pulse, T1 is the time is measured from the stimulus pulse to the first extremum (Vmax or Vmin). T2 is the time measured from the current pulse to the second extremum (Vmax or Vmin). The values of T1 and T2 are each compiled into a histogram with Thin msec bin widths. The value of T1 and T2 used for artifact rejection is the center value of the largest bin in the histogram. To reject artifacts when acquiring the EMG response, Vmax and Vmin are acquired only during windows that are T1±Twin and T2±Twin. Again, with reference to FIG. 6, Vpp is Vmax−Vmin. The method of automatic artifact rejection is further explained with reference to FIG. 10. While the threshold hunting algorithm is active, after each stimulation, the following steps are undertaken for each EMG sensor channel that is in scope: (1) the time sample values for the waveform maximum and minimum (after stimulus artifact rejection) will be placed into a histogram; (2) the histogram bin size will be the same granularity as the sampling period; (3) the histogram will be emptied each time the threshold hunting algorithm is activated; (4) the histogram will provide two peaks, or modes, defined as the two bins with the largest counts; (5) the first mode is defined as T1; the second mode is defined as T2; (6) a (possibly discontinuous) range of waveform samples will be identified; (7) for the first stimulation after the threshold hunting algorithm is activated, the range of samples will be the entire waveform; (8) after a specified number of stimulations, the range of samples will be limited to T1±0.5 ms and T2±0.5 ms; and (9) before the specified number of stimulations, either range may be used, subject to this restriction: the proportion of stimulations using the entire waveform will decrease from 100% to 0% (a sample of the curve governing this proportion is shown in FIG. 11). Peak-to-peak voltage (Vpp) will be measured either over the identified range of waveform samples. The specified number of stimulations will preferably be between 220 and 240. According to another aspect of the present invention, the maximum frequency of the stimulation pulses is automatically obtained with reference to FIG. 12. After each stimulation, Fmax will be computed as: Fmax=1/(T2+Safety Margin) for the largest value of T2 from each of the active EMG channels. In one embodiment, the Safety Margin is 5 ms, although it is contemplated that this could be varied according to any number of suitable durations. Before the specified number of stimulations, the stimulations will be performed at intervals of 100-120 ms during the bracketing state, intervals of 200-240 ms during the bisection state, and intervals of 400-480 ms during the monitoring state. After the specified number of stimulations, the stimulations will be performed at the fastest interval practical (but no faster than Fmax) during the bracketing state, the fastest interval practical (but no faster than Fmax/2) during the bisection state, and the fastest interval practical (but no faster than Fmax/4) during the monitoring state. The maximum frequency used until Fmax is calculated is preferably 10 Hz, although slower stimulation frequencies may be used during some acquisition algorithms. The value of Fmax used is periodically updated to ensure that it is still appropriate. This feature is represented graphically, by way of example only, in FIG. 12. For physiological reasons, the maximum frequency for stimulation will be set on a per-patient basis. Readings will be taken from all myotomes and the one with the slowest frequency (highest T2) will be recorded. Nerve Direction Once a nerve is detected using the working cannula 28 or dilating cannulae 26, the surgeon may use the Direction Function to determine the angular direction to the nerve relative to a reference mark on the access components 24-28. This is also shown in FIG. 7 as the arrow A pointing to the direction of the nerve. This information helps the surgeon avoid the nerve as he or she advances the cannula. The direction from the cannula to a selected nerve is estimated using the 4 orthogonal electrodes on the tip of the dilating cannula 26 and working cannulae 28. These electrodes are preferably scanned in a monopolar configuration (that is, using each of the 4 electrodes as the stimulation source). The nerve's threshold current (Ithresh) is found for each of the electrodes by measuring the muscle evoked potential response Vpp and comparing it to a known threshold Vthresh. This algorithm is used to determine the direction from a stimulation electrode to a nerve. As shown in FIG. 13, the four (4) electrodes are placed on the x and y axes of a two dimensional coordinate system at radius R from the origin. A vector is drawn from the origin along the axis corresponding to each electrode that has a length equal to IThresh for that electrode. The vector from the origin to a direction pointing toward the nerve is then computed. This algorithm employs the T1/T2 algorithm discussed above with reference to FIG. 6. Using the geometry shown in FIG. 13, the (x,y) coordinates of the nerve, taken as a single point, can be determined as a function of the distance from the nerve to each of four electrodes. This can be expressly mathematically as follows: Where the “circles” denote the position of the electrode respective to the origin or center of the cannula and the “octagon” denotes the position of a nerve, and d1, d2, d3, and d4 denote the distance between the nerve and electrodes 1-4 respectively, it can be shown that: x = d 1 2 - d 3 2 - 4 R and y = d 2 2 - d 4 2 - 4 R Where R is the cannula radius, standardized to 1, since angles and not absolute values are measured. After conversion from (x,y) to polar coordinates (r,θ), then θ is the angular direction to the nerve. This angular direction is then displayed to the user as shown in FIG. 7, by way of example only, as arrow A pointing towards the nerve. In this fashion, the surgeon can actively avoid the nerve, thereby increasing patient safety while accessing the surgical target site. The surgeon may select any one of the 4 channels available to perform the Direction Function. The surgeon should preferably not move or rotate the instrument while using the Direction Function, but rather should return to the Detection Function to continue advancing the instrument. Insertion and advancement of the access instruments 24-28 should be performed at a rate sufficiently slow to allow the surgical system 10 to provide real-time indication of the presence of nerves that may lie in the path of the tip. To facilitate this, the threshold current IThresh may be displayed such that it will indicate when the computation is finished and the data is accurate. For example, when the detection information is up to date and the instrument is now ready to be advanced by the surgeon, it is contemplated to have the color display show up as saturated to communicate this fact to the surgeon. During advancement of the instrument, if a channel's color range changes from green to yellow, advancement should proceed more slowly, with careful observation of the detection level. If the channel color stays yellow or turns green after further advancement, it is a possible indication that the instrument tip has passed, and is moving farther away from the nerve. If after further advancement, however, the channel color turns red, then it is a possible indication that the instrument tip has moved closer to a nerve. At this point the display will show the value of the stimulation current threshold in mA. Further advancement should be attempted only with extreme caution, while observing the threshold values, and only if the clinician deems it safe. If the clinician decides to advance the instrument tip further, an increase in threshold value (e.g. from 3 mA to 4 mA) may indicate the Instrument tip has safely passed the nerve. It may also be an indication that the instrument tip has encountered and is compressing the nerve. The latter may be detected by listening for sporadic outbursts, or “pops”, of nerve activity on the free running EMG audio output (as mentioned above). If, upon further advancement of the instrument, the alarm level decreases (e.g., from 4 mA to 3 mA), then it is very likely that the instrument tip is extremely close to the spinal nerve, and to avoid neural damage, extreme caution should be exercised during further manipulation of the Instrument. Under such circumstances, the decision to withdraw, reposition, or otherwise maneuver the instrument is at the sole discretion of the clinician based upon available information and experience. Further radiographic imaging may be deemed appropriate to establish the best course of action. Nerve Pathology As noted above, the surgical system 10 accomplishes neural pathology monitoring by electrically stimulating a retracted nerve root via one or more stimulation electrodes at the distal end of the nerve root retractor 30 while monitoring the EMG responses of the muscle group innervated by the particular nerve. FIG. 14 shows the differences between a healthy nerve (A) and a pathologic or unhealthy nerve (B). The inventors have found through experimentation that information regarding nerve pathology (or “health” or “status”) can be extracted from the recruitment curves generated according to the present invention (see, e.g., discussion accompanying FIGS. 3-5). In particular, it has been found that a healthy nerve or nerve bundle will produce a recruitment curve having a generally low threshold or “hanging point” (in terms of both the y-axis or Vpp value and the x-axis or IStim value), a linear region having a relatively steep slope, and a relatively high saturation region (similar to those shown on recruitment curve “A” in FIG. 14). On the contrary, a nerve or nerve bundle that is unhealthy or whose function is otherwise compromised or impaired (such as being impinged by spinal structures or by prolonged retraction) will produce a recruitment curve having a generally higher threshold (again, in terms of both the y-axis or Vpp value and the x-axis or Istim value), a linear region of reduced slope, and a relatively low saturation region (similar to those shown on recruitment curve “B” in FIG. 14). By recognizing these characteristics, one can monitor nerve root being retracted during a procedure to determine if its pathology or health is affected (i.e. negatively) by such retraction. Moreover, one can monitor a nerve root that has already been deemed pathologic or unhealthy before the procedure (such as may be caused by being impinged by bony structures or a bulging annulus) to determine if its pathology or health is affected (i.e. positively) by the procedure. The surgical system 10 and related methods have been described above according to one embodiment of the present invention. It will be readily appreciated that various modifications may be undertaken, or certain steps or algorithms omitted or substituted, without departing from the scope of the present invention. By way of example only, certain of these alternate embodiments or methods will be described below. a. Hanging Point Detection Via Linear Regression As opposed to identifying the stimulation current threshold (IThresh) based on a predetermined VThresh (such as described above and shown in FIG. 5), it is also within the scope of the present invention to determine IThresh via linear regression. This may be accomplished via, by way of example only, the linear regression technique disclosed in commonly owned and co-pending U.S. patent application Ser. No. 09/877,713, filed Jun. 8, 2001 and entitled “Relative Nerve Movement and Status Detection System and Methods,” the entire contents of which is hereby expressly incorporated by reference as if set forth in this disclosure in its entirety. b. Hanging Point Detection Via Dynamic Sweep Subtraction With reference to FIG. 15, the hanging point or threshold may also be determined by the following dynamic sweep subtraction method. The nerve is stimulated in step 80 using current pulses that increase from IMin to IMax (as described above). The resulting neuromuscular response (evoked EMG) for the associated muscles group is acquired in step 82. The peak-to-peak voltage (Vpp) is then extracted in step 84 for each current pulse according to the T1, T2 algorithm described above with reference to FIGS. 3-6. A first recruitment curve (S1) is then generated by plotting Vpp vs. IStim in step 86. The same nerve is then stimulated such that, in step 88, the peak-to-peak voltage (Vpp) may be extracted by subtracting the VMax from VMin of each EMG response without the T1, T2 filters employed in step 84. A second recruitment curve (S2) is then generated in step 90 by plotting Vpp vs. IStim. The generation of both recruitment curves S1, S2 continues until the maximum stimulation current (IMax) is reached (per the decision step 92). If IMax is not reached, the stimulation current IStim is incremented in step 94. If IMax is reached, then the first recruitment curve S1 is subtracted from the second recruitment curve S2 in step 96 to produce the curve “C” shown in step 98. By subtracting S1 from S2, the resulting curve “C” is actually the onset portion of the recruitment curve (that is, the portion before the threshold is reached) for that particular nerve. In this fashion, the last point in the curve “C” is the point with the greatest value of IStim and hence the hanging point. c. Peripheral Nerve Pathology Monitoring Similar to the nerve pathology monitoring scheme described above, the present invention also contemplates the use of one or more electrodes disposed along a portion or portions of an instrument (including, but not limited to, the access components 24-28 described above) for the purpose of monitoring the change, if any, in peripheral nerves during the course of the procedure. In particular, this may be accomplished by disposing one or more stimulation electrodes a certain distance from the distal end of the instrument such that, in use, they will likely come in contact with a peripheral nerve. For example, a mid-shaft stimulation electrode could be used to stimulate a peripheral nerve during the procedure. In any such configuration, a recruitment curve may be generated for the given peripheral nerve such that it can be assessed in the same fashion as described above with regard to the nerve root retractor, providing the same benefits of being able to tell if the contact between the instrument and the nerve is causing pathology degradation or if the procedure itself is helping to restore or improve the health or status of the peripheral nerve. d. Virtual Patient for Evoked Potential Simulation With reference to FIG. 16, the present invention also contemplates the use of a “virtual patient” device for simulating a naturally occurring recruitment curve. This is advantageous in that it provides the ability to test the various systems disclosed herein, which one would not be able to test without an animal and/or human subject. Based on the typically high costs of obtaining laboratory and/or surgical time (both in terms of human capital and overhead), eliminating the requirement of performing actual testing to obtain recruitment curves is a significant offering. According to the present invention, this can be accomplished by providing a device (not shown) having suitable software and/or hardware capable of producing the signal shown in FIG. 16. The device will preferably accept a sweeping current signal according to the present invention (that is, 200 microseconds width pulses sweeping in amplitude from 0-100 mA) and produce a voltage pulse having a peak-to-peak voltage (Vpp) that varies with the amplitude of the current input pulse. The relationship of the output Vpp and the input stimulation current will produce a recruitment curve similar to that shown. In one embodiment, the device includes various adjustments such that the features of the recruitment curve may be selectively modified. For example, the features capable of being modified may include, but are not necessarily limited to, Vpp at onset, maximum stimulation current of onselt (hanging point), the slope of the linear region and/or the Vpp of the saturation region. While this invention has been described in terms of a best mode for achieving this invention's objectives, it will be appreciated by those skilled in the art that variations may be accomplished in view of these teachings without deviating from the spirit or scope of the present invention. For example, the present invention may be implemented using any combination of computer programming software, firmware or hardware. As a preparatory step to practicing the invention or constructing an apparatus according to the invention, the computer programming code (whether software or firmware) according to the invention will typically be stored in one or more machine readable storage mediums such as fixed (hard) drives, diskettes, optical disks, magnetic tape, semiconductor memories such as ROMs, PROMs, etc., thereby making an article of manufacture in accordance with the invention. The article of manufacture containing the computer programming code is used by either executing the code directly from the storage device, by copying the code from the storage device into another storage device such as a hard disk, RAM, etc. or by transmitting the code on a network for remote execution. As can be envisioned by one of skill in the art, many different combinations of the above may be used and accordingly the present invention is not limited by the scope of the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>I. Field of the Invention This invention relates to nerve monitoring systems and to nerve muscle monitoring systems, and more particularly to systems and methods for determining nerve proximity, nerve direction, and pathology during surgery. II. Description of Related Art Systems and methods exist for monitoring nerves and nerve muscles. One such system determines when a needle is approaching a nerve. The system applies a current to the needle to evoke a muscular response. The muscular response is visually monitored, typically as a shake or “twitch.” When such a muscular response is observed by the user, the needle is considered to be near the nerve coupled to the responsive muscle. These systems require the user to observe the muscular response (to determine that the needle has approached the nerve). This may be difficult depending on the competing tasks of the user. In addition, when general anesthesia is used during a procedure, muscular response may be suppressed, limiting the ability of a user to detect the response. While generally effective (although crude) in determining nerve proximity, such existing systems are incapable of determining the direction of the nerve to the needle or instrument passing through tissue or passing by the nerves. This can be disadvantageous in that, while the surgeon may appreciate that a nerve is in the general proximity of the instrument, the inability to determine the direction of the nerve relative to the instrument can lead to guess work by the surgeon in advancing the instrument and thereby raise the specter of inadvertent contact with, and possible damage to, the nerve. Another nerve-related issue in existing surgical applications involves the use of nerve retractors. A typical nerve retractor serves to pull or otherwise maintain the nerve outside the area of surgery, thereby protecting the nerve from inadvertent damage or contact by the “active” instrumentation used to perform the actual surgery. While generally advantageous in protecting the nerve, it has been observed that such retraction can cause nerve function to become impaired or otherwise pathologic over time due to the retraction. In certain surgical applications, such as spinal surgery, it is not possible to determine if such retraction is hurting or damaging the retracted nerve until after the surgery (generally referred to as a change in “nerve health” or “nerve status”). There are also no known techniques or systems for assessing whether a given procedure is having a beneficial effect on a nerve or nerve root known to be pathologic (that is, impaired or otherwise unhealthy). Based on the foregoing, a need exists for a better system and method that can determine the proximity of a surgical instrument (including but not limited to a needle, catheter, cannula, probe, or any other device capable of traversing through tissue or passing near nerves or nerve structures) to a nerve or group of nerves during surgery. A need also exists for a system and method for determining the direction of the nerve relative to the surgical instrument. A still further need exists for a manner of monitoring nerve health or status during surgical procedures. The present invention is directed at eliminating, or at least reducing the effects of, the above-described problems with the prior art, as well as addressing the above-identified needs. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention includes a system and related methods for determining nerve proximity and nerve direction to surgical instruments employed in accessing a surgical target site, as well as monitoring the status or health (pathology) of a nerve or nerve root during surgical procedures. According to a broad aspect, the present invention includes a surgical system, comprising a control unit and a surgical instrument. The control unit has at least one of computer programming software, firmware and hardware capable of delivering a stimulation signal, receiving and processing neuromuscular responses due to the stimulation signal, and identifying a relationship between the neuromuscular response and the stimulation signal. The surgical instrument has at least one stimulation electrode electrically coupled to said control unit for transmitting the stimulation signal, wherein said control unit is capable of determining at least one of nerve proximity, nerve direction, and nerve pathology relative to the surgical instrument based on the identified relationship between the neuromuscular response and the stimulation signal. In a further embodiment of the surgical system of the present invention, the control unit is further equipped to communicate at least one of alpha-numeric and graphical information to a user regarding at least one of nerve proximity, nerve direction, and nerve pathology. In a further embodiment of the surgical system of the present invention, the surgical instrument may comprise at least one of a device for maintaining contact with a nerve during surgery, a device for accessing a surgical target site, and a device for testing screw placement integrity. In a further embodiment of the surgical system of the present invention, the surgical instrument comprises a nerve root retractor and wherein the control unit determines nerve pathology based on the identified relationship between the neuromuscular response and the stimulation signal. In a further embodiment of the surgical system of the present invention, the surgical instrument comprises a dilating instrument and wherein the control unit determines at least one of proximity and direction between a nerve and the instrument based on the identified relationship between the neuromuscular response and the stimulation signal. In a further embodiment of the surgical system of the present invention, the dilating instrument comprises at least one of a K-wire, an obturator, a dilating cannula, and a working cannula. In a further embodiment of the surgical system of the present invention, the surgical instrument comprises a screw test probe and wherein the control unit determines the proximity between the screw test probe and an exiting spinal nerve root to assess whether a medial wall of a pedicle has been breached by at least one of hole formation and screw placement. | 20040109 | 20111129 | 20050818 | 59394.0 | 1 | KAHELIN, MICHAEL WILLIAM | SYSTEM AND METHODS FOR DETERMINING NERVE PROXIMITY, DIRECTION, AND PATHOLOGY DURING SURGERY | UNDISCOUNTED | 1 | CONT-ACCEPTED | 2,004 |
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10,755,000 | ACCEPTED | Methods for deposition of semiconductor material | The invention includes a method for selective deposition of semiconductor material. A substrate is placed within a reaction chamber. The substrate comprises a first surface and a second surface. The first and second surfaces are exposed to a semiconductor material precursor under conditions in which growth of semiconductor material from the precursor comprises a lag phase prior to a growth phase, and under which it takes longer for the growth phase to initiate on the second surface than on the first surface. The exposure of the first and second surfaces is conducted for a time sufficient for the growth phase to occur on the first surface, but not long enough for the growth phase to occur on the second surface. | 1. A method for deposition of semiconductor material, comprising: providing a substrate, the substrate comprising a first material and a second material; exposing the first and second materials to at least one semiconductor material precursor under conditions in which growth of semiconductor material from the at least one precursor over the first and second materials comprises a lag phase period prior to a growth phase, and under which it takes longer for the growth phase to initiate on the second material than on the first material; and the exposing being conducted for long enough for the growth phase to occur on the first material, but not for long enough for the growth phase to substantially occur on the second material. 2. The method of claim 1 wherein the growth phase of the semiconductor material on the first material forms a layer of the semiconductor material having a thickness of from about 10 Å to about 5000 Å. 3. The method of claim 2 wherein the semiconductor material is a single crystal material epitaxially grown over the first material. 4. The method of claim 1 wherein the exposing is conducted in a reaction chamber and comprises a pulse of the at least one precursor into the chamber followed by a purge to remove the at least one precursor substantially entirely from within the chamber. 5. The method of claim 4 wherein the purge utilizes one or more of H2, Cl2 and HCl. 6. The method of claim 5 wherein the purge utilizes H2 without a chlorine-containing component. 7. The method of claim 4 wherein a sequence comprising two or more of the pulses is utilized to form a thickness of semiconductor material. 8. The method of claim 7 wherein the same semiconductor precursor is flowed into the chamber during each of the two or more pulses. 9. The method of claim 7 wherein a different semiconductor precursor is flowed into the chamber during one of the two or more pulses relative to another of the two or more pulses. 10. The method of claim 1 further comprising flowing an etchant into the reaction chamber during at least some of the exposing, and wherein the etchant is suitable for etching some of the semiconductor material. 11. The method of claim 1 wherein no etchant suitable for etching the semiconductor material is within the reaction chamber during the exposing. 12. The method of claim 1 further comprising flowing a halogen-containing material into the reaction chamber during at least some of the exposing. 13. The method of claim 12 wherein the halogen of the halogen-containing material is Cl. 14. The method of claim 12 wherein the halogen-containing material is HCl and is present in the reaction chamber to a concentration of less than or equal to about 0.1 volume percent. 15. The method of claim 1 wherein the semiconductor material consists essentially of one or both of silicon and germanium. 16. The method of claim 1 wherein the semiconductor material consists essentially of silicon. 17. The method of claim 1 wherein the semiconductor material consists essentially of germanium. 18. The method of claim 1 wherein the semiconductor material consists of one or both of silicon and germanium. 19. The method of claim 1 wherein the semiconductor material consists of silicon. 20. The method of claim 1 wherein the semiconductor material consists of germanium. 21. The method of claim 1 wherein the first material comprises a semiconductor material and wherein the second material comprises an electrically insulative material. 22. The method of claim 21 wherein the first material is monocrystalline or polycrystalline. 23. The method of claim 21 wherein the first material consists essentially of doped or undoped silicon. 24. The method of claim 23 wherein the second material consists essentially of silicon and one or both of oxygen and nitrogen. 25. The method of claim 21 wherein the first material consists of doped or undoped silicon. 26. The method of claim 25 wherein the second material consists of silicon and one or both of oxygen and nitrogen. 27. The method of claim 21 wherein the first material consists essentially of doped or undoped germanium. 28. The method of claim 27 wherein the second material consists essentially of silicon and one or both of oxygen and nitrogen. 29. The method of claim 21 wherein the first material consists of doped or undoped germanium. 30. The method of claim 29 wherein the second material consists of silicon and one or both of oxygen and nitrogen. 31. The method of claim 21 wherein the first material consists essentially of doped or undoped silicon/germanium. 32. The method of claim 31 wherein the second material consists essentially of silicon and one or both of oxygen and nitrogen. 33. The method of claim 21 wherein the first material consists of doped or undoped silicon/germanium. 34. The method of claim 33 wherein the second material consists of silicon and one or both of oxygen and nitrogen. 35. A method for deposition of semiconductor material, comprising: providing a substrate within a reaction chamber, the substrate including a first material with a first surface and including a second material with a second surface; providing a semiconductor material precursor having a first activation time associated therewith for forming semiconductor material over the first surface and a second activation time associated therewith for forming semiconductor material over the second surface, the second activation time being longer than the first activation time; and providing a pulse of the semiconductor material precursor within the chamber, the pulse being maintained in the chamber for a time longer than the first activation time and no greater than the second activation time to selectively form semiconductor material from the semiconductor material precursor over the first surface relative to the second surface. 36. The method of claim 35 wherein the semiconductor material formed from the precursor deposits over the first surface as a crystalline layer. 37. The method of claim 35 wherein the pulse is followed with a purge utilizing one or more of H2, Cl2 and HCl to remove the semiconductor material precursor substantially entirely from within the chamber. 38. The method of claim 36 wherein the purge utilizes H2 without a chlorine-containing component. 39. The method of claim 35 wherein two or more of the pulses are sequentially utilized to form a stack of semiconductor material. 40. The method of claim 39 wherein the same semiconductor precursor is flowed into the chamber during each of the two or more pulses. 41. The method of claim 39 wherein a different semiconductor precursor is flowed into the chamber during one of the two or more pulses relative to another of the two or more pulses. 42. The method of claim 35 further comprising flowing a halogen acid into the chamber during at least some of the time of the pulse of the semiconductor material precursor. 43. The method of claim 42 wherein the halogen acid is HCl. 44. The method of claim 42 wherein the halogen acid is HCl and is present in the reaction chamber to a concentration of less than or equal to about 0.1 volume percent. 45. The method of claim 35 wherein substantially no halogen acid is present within the chamber during the time of the pulse of the semiconductor material precursor. 46. The method of claim 35 wherein the semiconductor material precursor is selected from the group consisting of dichlorosilane, trichlorosilane, tetrachlorosilane, disilane, silane and germane. 47. The method of claim 35 wherein the semiconductor material of the semiconductor material precursor is silicon. 48. The method of claim 35 wherein the semiconductor material of the semiconductor material precursor is germanium. 49. The method of claim 35 wherein the first surface consists essentially of doped or undoped silicon. 50. The method of claim 49 wherein the second surface consists essentially of silicon and one or both of oxygen and nitrogen. 51. The method of claim 35 wherein the first material consists of doped or undoped silicon. 52. The method of claim 51 wherein the second material consists of silicon and one or both of oxygen and nitrogen. 53. The method of claim 35 wherein the first material consists essentially of doped or undoped germanium. 54. The method of claim 53 wherein the second material consists essentially of silicon and one or both of oxygen and nitrogen. 55. The method of claim 35 wherein the first material consists of doped or undoped germanium. 56. The method of claim 55 wherein the second material consists of silicon and one or both of oxygen and nitrogen. 57. The method of claim 35 wherein the first material consists essentially of doped or undoped silicon/germanium. 58. The method of claim 57 wherein the second material consists essentially of silicon and one or both of oxygen and nitrogen. 59. The method of claim 35 wherein the first material consists of doped or undoped silicon/germanium. 60. The method of claim 59 wherein the second material consists of silicon and one or both of oxygen and nitrogen. 61. A method for deposition of semiconductor material, comprising: providing a substrate within a reaction chamber, the substrate having a first surface consisting essentially of one or more semiconductor materials, the substrate having a second surface consisting of one or more electrically insulative materials; providing a pulse of at least one precursor selected from the group of silicon-containing precursors and germanium-containing precursors within the reaction chamber and utilizing the at least one precursor for depositing a substance comprising one or both of silicon and germanium over the substrate; the depositing of the substance over the substrate occurring under conditions in which depositing of the substance over the first and second surfaces comprises nucleation phase/growth phase dynamics, and under which it takes longer for the growth phase to initiate over the second surface than over the first surface; and the pulse having a sufficient duration to substantially initiate the growth phase over the first surface but not being of sufficient duration to substantially initiate the growth phase over the second surface. 62. The method of claim 61 wherein: the pulse is a first pulse of the at least one precursor and forms a layer of the deposited substance; the first pulse is followed with a purge to remove the at least one precursor substantially entirely from within the chamber; and the purge is followed with a second pulse of the at least one precursor into the chamber; the second pulse being for a sufficient duration to substantially initiate the growth phase over the layer of the deposited substance but not of sufficient duration to substantially initiate the growth phase over the second surface. 63. The method of claim 62 wherein the purge utilizes at least one halogen-containing component. 64. The method of claim 62 wherein the purge utilizes no halogen-containing component. 65. The method of claim 62 wherein the purge utilizes H2 and one or both of Cl2 and HCl. 66. The method of claim 61 further comprising flowing a halogen-containing material into the chamber during at least some of the time of the pulse of the at least one precursor. 67. The method of claim 61 further comprising flowing a halogen acid into the chamber during at least some of the time of the pulse of the at least one precursor. 68. The method of claim 67 wherein the halogen acid is HCl. 69. The method of claim 67 wherein the halogen acid is HCl and is present in the reaction chamber to a concentration of less than or equal to about 0.1 volume percent. 70. The method of claim 61 wherein substantially no halogen acid is present within the chamber during the time of the pulse of the at least one precursor. 71. The method of claim 61 wherein the at least one precursor is selected from the group consisting of dichlorosilane, trichlorosilane, tetrachlorosilane, disilane, silane, germane and mixtures thereof. 72. The method of claim 61 wherein the first surface is polycrystalline. 73. The method of claim 61 wherein the first surface is monocrystalline. 74. The method of claim 61 wherein the first surface consists essentially of one or both of germanium and silicon. 75. The method of claim 61 wherein the first surface consists of one or both of germanium and silicon. 76. The method of claim 61 wherein the second surface consists essentially of silicon and one or both of oxygen and nitrogen. 77. The method of claim 61 wherein the second surface consists of silicon and one or both of oxygen and nitrogen. | TECHNICAL FIELD The invention pertains to methods for deposition of semiconductor material. BACKGROUND OF THE INVENTION There are numerous applications in which it is desired to selectively deposit semiconductor material onto a semiconductor surface relative to other surfaces. For instance, it can be desired to epitaxially form one or both of silicon and germanium on a semiconductor surface. A prior art method of epitaxially forming semiconductor material over a semiconductor surface is described with reference to FIGS. 1-3. FIG. 1 shows a semiconductor wafer fragment 10 at a preliminary processing stage. Fragment 10 comprises a semiconductor substrate 12. Substrate 12 can comprise, consist essentially of, or consist of monocrystalline silicon. The silicon can be appropriately doped with one or more conductivity-enhancing dopants. For instance, the silicon can be lightly background doped with p-type dopant, and can comprise various conductively-doped diffusion regions (not shown) formed therein. To aid in interpretation of the claims that follow, the terms “semiconductive substrate” and “semiconductor substrate” are defined to mean any construction comprising semiconductive material, including, but not limited to, bulk semiconductive materials such as a semiconductive wafer (either alone or in assemblies comprising other materials thereon), and semiconductive material layers (either alone or in assemblies comprising other materials). The term “substrate” refers to any supporting structure, including, but not limited to, the semiconductive substrates described above. The term “semiconductor material” refers to a material comprising one or more of the semiconductive elements, such as, for example, a material comprising one or both of silicon and germanium. An electrically insulative material 14 is formed over substrate 12. Material 14 can comprise, consist essentially of, or consist of silicon and one or both of oxygen and nitrogen. For instance, material 14 can comprise silicon dioxide, silicon nitride, and/or silicon oxynitride. In the illustrated example, substrate 12 has an upper surface 13, and material 14 is formed directly against (i.e., in physical contact with) the upper surface 13. Material 14 is patterned to have a gap 16 extending therethrough to the upper surface 13 of substrate 12. Material 14 has exposed surfaces 15. Referring to FIG. 2, a semiconductor material 18 is formed within gap 16 and also over the surfaces 15 of insulative material 14. Material 16 will typically comprise, consist essentially of, or consist of one or both of silicon and germanium. If material 16 comprises, consists essentially of, or consists of silicon, such material can be formed utilizing dichlorosilane, H2 and HCl. The dichlorosilane provides a silicon source. The H2 participates in the silicon deposition, and also can remove undesired oxides forming over the growing silicon. The HCl etches material 18 before the material can form a uniform layer over insulative material 14. Specifically, the material 18 nucleates over insulative material 14 to form small islands on surface 15, as shown. The HCl continuously etches material 18 from the small islands, and accordingly removes material 18 from the islands before the islands can merge to form a continuous layer. The HCl is also thought to remove material 18 which is growing over surface 13 (the shown material 18 within gap 16), but such removal is too slow to prevent the layer of material 18 from forming within gap 16. Accordingly, the HCl effectively creates a selective deposition of material 18 over the surface 13 of semiconductor material 12 relative to the surfaces 15 of insulative material 14. The HCl can be replaced with Cl2 in some aspects of the prior art. FIG. 3 shows construction 10 at the conclusion of the epitaxial growth, and shows that the semiconductor material 18 has been selectively formed over surface 13 of semiconductor substrate 12 relative to surfaces 15 of insulative material 14. A problem with the processing of FIGS. 1-3 is that the utilization of HCl significantly slows the rate of deposition of semiconductor material 18 relative to a rate which would occur in the absence of the HCl. Accordingly, it is desired to develop deposition processes which can selectively form a semiconductor material over an exposed semiconductor substrate surface relative to exposed surfaces of non-semiconductor materials, and which have a higher rate than the processing sequence of FIGS. 1-3. The processing sequence of FIGS. 1-3 is an exemplary prior art process. Other processes have been developed which are modifications of the process described with reference to FIGS. 1-3. For instance, in one modification a semiconductor precursor (such as, for example, dichlorosilane) is provided in combination with H2 to form semiconductor material 18 over a surface of a semiconductor substrate and over surfaces of insulative materials. After the growth of the semiconductor material, HCl is provided to selectively remove the semiconductor material from over the insulative materials surfaces while leaving a layer of the semiconductor material over the semiconductor substrate surface. In some aspects, the cycling of deposition of semiconductor material, etching of semiconductor material from over insulative material surfaces, deposition of the material, etching of the material, etc., is repeated multiple times to form a semiconductor material to a desired thickness over a semiconductor substrate surface. A particular prior art methodology flows disilane for about 10 seconds, then Cl2 for about 10 seconds, then H2 for about 10 seconds, and repeats the process multiple times to form a semiconductor layer to a desired thickness over a semiconductor substrate surface. FIGS. 4 and 5 illustrate another exemplary prior art application for selective formation of epitaxially-grown semiconductor material over a semiconductor substrate. Referring initially to FIG. 4, a wafer fragment 20 comprises a substrate 22. Substrate 22 can comprise the same construction as described previously relative to substrate 12 of FIG. 1, and accordingly can comprise monocrystalline silicon lightly-background doped with p-type dopant. Substrate 22 comprises an upper surface 23. An isolation region 24 extends within substrate 22. Isolation region 24 can comprise, for example, a shallow trench isolation region, and accordingly can comprise silicon dioxide. Isolation region 24 comprises an upper surface 25. A transistor gate 26 is formed over surface 23 of substrate 22. Transistor gate 26 comprises an insulative material 28, a conductive material 30, and an insulative cap 32. Insulative material 28 can comprise, for example, silicon dioxide, and can be referred to as pad oxide. Conductive material 30 can comprise, for example, one or more of metal, metal compounds and conductively-doped semiconductor material (such as, for example, conductively-doped silicon). Insulative cap 32 can comprise, consist essentially of, or consist of silicon together with one or both of oxygen and nitrogen. For instance, insulative cap 32 can comprise, consist essentially of, or consist of silicon dioxide, silicon nitride, or silicon oxynitride. Insulative cap 32 comprises an upper exposed surface 33. An anisotropically-etched sidewall spacer 34 is along a sidewall of transistor gate 26. Spacer 34 can comprise, consist essentially of, or consist of silicon together with one or both of oxygen and nitrogen. Accordingly, spacer 34 can comprise, or consist essentially of, or consist of one or more of silicon dioxide, silicon nitride and silicon oxynitride. Spacer 34 has an exposed surface 35. A conductively-doped diffusion region 36 extends within substrate 22 beside transistor gate 26. The conductively-doped diffusion region 36 and transistor gate 26 can be together incorporated into a transistor device. Referring to FIG. 5, a semiconductor material 38 is formed over surface 23 of semiconductor substrate 22 selectively relative to surfaces 25 and 33 of insulative materials 24 and 32, respectively. Semiconductor material 38 can comprise, consist essentially of, or consist of one or both of silicon and germanium, and can be formed utilizing processing analogous to that described previously with reference to FIGS. 1-3. Accordingly, the semiconductor material can be formed by deposition from a semiconductor precursor in combination with an etch which removes the deposited material from over surfaces 25 and 33 while leaving the material over surface 23. An undesired consequence of the etch is that such rounds an outer corner of deposited material 38, as can be seen at a location 40 in the diagram of FIG. 5. The rounded outer corner can be referred to as a faceted corner, and can increase degradation of a transistor device component (with a common effect being p-channel degradation), and can also adversely affect an implant profile if a dopant is implanted either into or through semiconductor material 38. For instance, conductively-doped diffusion region 36 would sometimes be formed by an implant subsequent to formation of material 38 rather than being present prior to deposition of semiconductor material 38. The rounded faceted corner 40 could then adversely affect formation of the diffusion region 36. The semiconductor material 38 of FIG. 5 can ultimately be conductively doped, and can be incorporated into, for example, an elevated source/drain region associated with a transistor device comprising gate 26. Numerous problems are encountered during the processing described above with reference to FIGS. 1-5. Such problems include the faceted corner 40 and slow growth rate discussed previously. Another problem is that the deposition rate and quality can be sensitive to the amount of etchant (such as, for example, HCl) utilized during the deposition/etch processing, which can make it problematic to control wafer throughput and quality in a fabrication process. For instance, it is sometimes found that increasing HCl flow by 10% will decrease the growth rate of a deposited semiconductor material by about 20%. It would be desirable to develop deposition methods which alleviate, and preferably eliminate, some or all of the above-discussed problems. SUMMARY OF THE INVENTION In one aspect, the invention encompasses a method for deposition of semiconductor material. A substrate is provided within a reaction chamber. The substrate includes a first material and a second material, with the second material having a different composition than the first material. The first and second materials are exposed to a semiconductor material precursor under conditions in which growth of semiconductor material from the precursor comprises a lag phase prior to a growth phase. The conditions are also such that it takes longer for the growth phase to initiate on the second material than on the first material. A concentration of the precursor is pulsed into the chamber. The duration of the pulse is long enough for the growth phase to substantially occur on the first material, but not long enough for the growth phase to substantially occur on the second material. In one aspect, the invention encompasses a method for deposition of a semiconductor material comprising one or both of silicon and germanium. A substrate is provided within a reaction chamber. The substrate has a first surface consisting essentially of one or more semiconductor materials and a second surface consisting of one or more electrically insulative materials. The first and second surfaces are exposed to at least one precursor selected from the group consisting of silicon-containing precursors and germanium-containing precursors to deposit a substance comprising one or both of silicon and germanium over the substrate. The exposure is under conditions in which deposition of the substance over the first and second surfaces comprises nucleation phase/growth phase dynamics, and under which it takes longer for the growth phase to initiate over the second surface than over the first surface. The exposure is conducted for a time long enough to substantially initiate the growth phase over the first surface but not long enough to substantially initiate the growth phase over the second surface. Thus, the substance is selectively formed over the first surface relative to the second surface. BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments of the invention are described below with reference to the following accompanying drawings. FIG. 1 is a diagrammatic, cross-sectional view of a semiconductor wafer fragment shown at a preliminary stage of a prior art process. FIG. 2 is a view of the FIG. 1 wafer fragment shown at a prior art processing stage subsequent to that of FIG. 1. FIG. 3 is a view of the FIG. 1 wafer fragment shown at a prior art processing stage subsequent to that of FIG. 2. FIG. 4 is a diagrammatic, cross-sectional view of a semiconductor wafer fragment shown at a preliminary processing stage of a second prior art process. FIG. 5 is a view of the FIG. 4 wafer fragment shown at a prior art processing stage subsequent to that of FIG. 4. FIG. 6 is a graphical illustration of time versus thickness illustrating the growth dynamics for semiconductor material over two different surfaces under particular conditions. FIG. 7 is a graphical illustration of gas flow versus time illustrating an exemplary processing sequence of an aspect of the present invention. FIG. 8 is a diagrammatic, cross-sectional view of a reaction chamber configured for utilization in an exemplary aspect of the present invention. FIG. 9 is a diagrammatic, cross-sectional view of a wafer fragment at a preliminary processing stage of an exemplary aspect of the present invention. FIG. 10 is a view of the FIG. 9 wafer fragment shown at a processing stage subsequent to that of FIG. 9. FIG. 11 is a view of the FIG. 9 wafer fragment shown at a processing stage subsequent to that of FIG. 10. FIG. 12 is a view of the FIG. 9 wafer fragment shown at a processing stage subsequent to that of FIG. 11. FIG. 13 is a diagrammatic, cross-sectional view of a semiconductor wafer fragment at a preliminary processing stage of a second embodiment aspect of the present invention. FIG. 14 is a view of the FIG. 13 wafer fragment shown at a processing stage subsequent to that of FIG. 13. FIG. 15 is a view of the FIG. 13 wafer fragment shown at a processing stage subsequent to that of FIG. 14. FIG. 16 is a view of the FIG. 13 wafer fragment shown at a processing stage subsequent to that of FIG. 15. FIG. 17 is a view of the FIG. 13 wafer fragment shown at the processing stage of FIG. 16 in accordance with an exemplary aspect of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS This disclosure of the invention is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws “to promote the progress of science and useful arts” (Article 1, Section 8). One aspect of the invention is a recognition that the dynamics of growth of deposited semiconductor materials on different surfaces can differ, and that this can be taken advantage of for selective deposition on particular surfaces. FIG. 6 is a graphical illustration of the dynamics of growth of a deposited semiconductor material on two different surfaces. One of the surfaces is a semiconductor material (the line labeled 50), and the other is an insulative material (the line labeled 60). The insulative material can consist of silicon together with one or both of oxygen and nitrogen (i.e., can consist of silicon dioxide, silicon nitride or silicon oxynitride). The rate of growth of the deposited semiconductor material over the surfaces is illustrated in the FIG. 6 graph as a change in thickness of the deposited material over time. Notably, the growth dynamics on both the semiconductor surface (line 50) and the insulative material surface (line 60) are similar in that both have a delay phase (lag phase) prior to a growth phase. Specifically, the thickness of the deposited material does not increase from the zero timepoint, but rather begins to increase after a lag phase. The lag phase for growth on the semiconductor material corresponds to time T1, and the lag phase for the growth on the insulative material corresponds to time T2. The lag phase for growth of the deposited material on the semiconductor material is significantly shorter than the lag phase for the growth on the insulative material. In exemplary applications, the lag phase T1 may be about 2 seconds, while the lag phase T2 may be about 10 seconds. The particular length of a lag phase can be impacted by the deposition conditions utilized. For instance, if the deposition conditions comprise a semiconductor precursor in the absence of an etchant material (such as HCl), the lag phases will be relatively short. In contrast, if an etchant is present the lag phases will be extended. Particular conditions may extend one of the lag phases T1 or T2 more than the other. Such can reduce the interval between T1 and T2 in some cases, and in other cases can increase the interval between T1 and T2. The lag phases T1 and T2 are believed to result from nucleation phase/growth phase dynamics during deposition of semiconductor material. Specifically, there is initially a nucleation phase of the deposited semiconductor material during which there is substantially no increase in the thickness of the material over an underlying surface. The nucleation phase then progresses to a growth phase, with the growth phase being defined as the phase in which there is a substantial increase in thickness of the deposited material. Accordingly, the lag phase times T1 and T2 correspond to the duration of the nucleation phases on the semiconductor surface and insulative material surface, respectively, and the lines 50 and 60 correspond to the growth phases on the semiconductor material surface and the insulative material surface, respectively. In some aspects, the growth phase can be considered a period of substantially linear increase in the thickness of a deposited material. The increased lag phase over an insulative material surface relative to a semiconductor surface can be taken advantage of to selectively deposit a semiconductor material on the semiconductor surface relative to the insulative material surface. Specifically, an insulative material surface and a semiconductor material surface can both be exposed to a pulse of semiconductor precursor, but the pulse can be of a duration which exceeds the lag phase T1 while being less than the lag phase T2. Accordingly, there will be growth of semiconductor material on the semiconductor surface, but there will not be growth of semiconductor material on the insulative material surface. An exemplary method is diagrammatically illustrated in FIG. 7. Specifically, FIG. 7 shows a graph of gas flow versus time for a pulse/purge sequence that can be utilized for growing semiconductor materials selectively over a semiconductor surface. Each pulse corresponds to flow of appropriate semiconductor material precursor within a reaction chamber to a sufficient concentration to grow semiconductor material over semiconductor surfaces and insulative material surfaces. The pulses are for a duration longer than the lag phase for growth on the semiconductor surface, but less than or equal to the lag phase for growth on the insulative material surface (i.e., of for a time longer than T1 of FIG. 6, but no greater than the time T2 of FIG. 6). After each pulse, the semiconductor material precursor is purged from within the reaction chamber. In particular aspects, the semiconductor material which is deposited comprises, consists essentially of, or consists of one or both of silicon and germanium. In such aspects, the semiconductor material precursor utilized during the pulses can be selected from the group consisting of dichlorosilane, trichlorosilane, tetrachlorosilane, disilane, silane and germane. The material utilized for the purge can comprise any suitable purge gas, and/or vacuum. If a purge gas is utilized, such can be inert relative to reaction with exposed substrate surfaces in the reaction chamber, or in some aspects can be reactive with one or more exposed materials in the reaction chamber. In particular aspects, the purge will comprise flowing a gas through a reaction chamber, with such gas containing H2. The gas can comprise a halogen-containing component in addition to the H2, such as, for example, Cl2, or a halogen acid, such as, for example, HCl. If HCl is utilized during the purge, such can be present in the reaction chamber to a concentration of less than 0.1 volume percent. The utilization of a halogen-containing material during the purge can be advantageous in that it can remove nucleated semiconductor materials from over insulative surfaces. However, it can slow down a deposition process by also removing deposited semiconductor material from over a semiconductor surface. Accordingly, the invention also encompasses aspects in which a purge gas does not include etchants. In some aspects, the purge gas utilizes H2 without any halogen-containing components, and specifically, without any chlorine-containing components. If halogen-containing material, or other etchant, is desired in the reaction chamber, such can be provided in the chamber during the pulsing of the semiconductor material into the reaction chamber alternatively to, or in addition to, providing the etchant during the purging. In exemplary aspects, HCl is present in the reaction chamber during the pulse of semiconductor material into the chamber, and is present to a concentration of less than 0.1 volume percent. The HCl can advantageously remove semiconductor material nucleating on insulative surfaces. A disadvantage of including etchants with deposition precursors is that the etchants can slow down a deposition process, and accordingly in some aspects it can be advantageous to not have etchants (such as, for example, Cl) present during the pulse of semiconductor material into a reaction chamber. FIG. 8 illustrates an exemplary reaction apparatus 70 that can be utilized in particular aspects of the present invention. Apparatus 70 comprises a chamber 72. A substrate holder 74 is within the chamber, and is shown holding an exemplary substrate 76. Substrate 76 can correspond to, for example, a semiconductor wafer, such as, for example, a monocrystalline silicon wafer. An inlet 78 extends into the chamber, and is blocked by a valve 80. An outlet 82 also extends into the chamber, and is blocked by a valve 84. In operation, materials are flowed into chamber 72 through inlet 78, and expelled from chamber 72 through outlet 82. The materials flowed into chamber 72 can be suitable reactants during a pulse of precursor into the chamber, and can be suitable purge gases during a purge of materials from the chamber. Additionally, a vacuum (not shown) can be provided downstream of outlet 82 to assist in purging materials from within the chamber. The apparatus 70 can be any suitable apparatus, including, for example, a chemical vapor deposition (CVD) apparatus, an atomic layer deposition (ALD) apparatus, a plasma-enhanced (PE) CVD or ALD apparatus, etc. FIGS. 9-12 illustrate an exemplary aspect of the invention. FIG. 9 shows a semiconductor wafer fragment 100 at a preliminary processing stage. Fragment 100 comprises a substrate 102 and an insulative material 104 over substrate 102. Substrate 102 can comprises identical materials to those discussed above for substrate 12 of FIG. 1. Accordingly, substrate 102 can comprise, consist essentially of, or consist of semiconductor materials, and in particular aspects will comprise, consist essentially of, or consist of one or both of silicon and germanium. Substrate 102 comprises an upper surface 103. The portion of substrate 102 comprised by surface 103 can be monocrystalline or polycrystalline, and in particular aspects will comprise, consist essentially of, or consist of one or both of silicon and germanium in monocrystalline or polycrystalline form. The semiconductor material of surface 103 can be doped or undoped. Specifically, surface 103 can be comprised by a conductively-doped diffusion region (not shown) in particular aspects of the invention, or can be comprised by undoped semiconductor material in other aspects of the invention. Insulative material 104 can comprise identical materials to those discussed above for material 14 of FIG. 1, and accordingly can comprise, consist essentially of, or consist of silicon in combination with one or both of nitrogen and oxygen. Insulative material 104 comprises a surface 105. In particular aspects, surface 105 can comprise, consist essentially of, or consist of one or more of silicon dioxide, silicon nitride and silicon oxynitride. Materials 102 and 104 can be referred to as first and second materials, respectively, in the discussion that follows; and surfaces 103 and 105 can be referred to as first and second surfaces respectively. In exemplary aspects of the invention, the wafer comprising fragment 100 is provided within a reaction chamber, such as, for example, the chamber above with reference to FIG. 8, and first and second surfaces 103 and 105 are exposed to at least one semiconductor material precursor. The surfaces are exposed to the precursor under conditions in which growth of semiconductor material from the precursor over the first and second materials 102 and 104 will comprise a lag phase prior to a growth phase, and under which it takes longer for the growth phase to initiate on surface 105 of material 104 than on surface 103 of material 102. The precursor is injected within the chamber to a sufficient concentration for growth of semiconductor material from the precursor on both first surface 103 and second surface 105. However, the precursor concentration is maintained within the chamber for a duration only long enough for the growth phase to substantially occur on first surface 103, and not long enough for the growth phase to substantially occur on second surface 105. A growth phase is considered to have “substantially occurred” on a surface if a detectable layer of uniform thickness has formed on the surface, and not if nucleated islands are the only deposition on the surface. The duration that the precursor concentration is maintained in the chamber can be considered a pulse of the precursor within the chamber. In some aspects, the deposition of semiconductor material on surfaces 103 and 105 can be considered to have a first activation time relative to surface 103, and a second activation time relative to surface 105. The term “activation time” refers to the time of the lag phase associated with growth of semiconductor material over the surfaces, and specifically is the time which elapses before the growth phase initiates. The activation time relative to surface 105 (the second activation time) is longer than the activation time relative to surface 103 (the first activation time). The semiconductor material precursor is pulsed into the chamber for a time longer than the first activation time and no greater than the second activation time. The pulse thus selectively deposits semiconductor material over the first surface 103 relative to the second surface 105. The precursor utilized for deposition of semiconductor material over surface 103 can comprise at least one precursor selected from the group of silicon-containing precursors and germanium-containing precursors. Accordingly, the semiconductor material deposited over surface 103 can comprise, consist essentially of, or consist of one or both of silicon and germanium. If the semiconductor material comprises both silicon and germanium, it can be referred to as silicon/germanium. In particular aspects, the precursor can comprise one or more materials selected from the group consisting of dichlorosilane, trichlorosilane, tetrachlorosilane, disilane, silane and germane. FIG. 10 shows fragment 100 after exposure of surfaces 103 and 105 to the semiconductor material precursor. A semiconductor material 110 is selectively formed over surface 103 relative to surface 105. Semiconductor material 110 can comprise any suitable semiconductor material, and in particular aspects will comprise, consist essentially of, or consist of one or both of silicon and germanium. The deposition of material 110 can be, in some aspects, considered a “blanket” deposition in that surfaces 103 and 105 are both exposed to precursor, even though the deposition is selective for the particular surface 103. The formation of material 110 can be accomplished utilizing the various conditions discussed above with reference to FIGS. 6 and 7. Accordingly, the formation of material 110 can be accomplished utilizing a semiconductor material precursor alone in the reaction chamber, or in combination with a halogen-containing material. Exemplary halogen-containing materials are halogen-containing acids (for example, HCl), and diatomic halogen molecules (for example, Cl2). If HCl is present in the reaction chamber during deposition of semiconductor material 110, the HCl will preferably be present in the chamber to a concentration of less than or equal to about 0.1 volume percent (i.e., the HCl will be present to a concentration of from greater than 0 volume percent to less than or equal to about 0.1 volume percent). In the shown aspect of the invention, material 110 is deposited to a thickness which is less than the initial thickness of material 104, and accordingly material 110 only partially fills a gap extending through material 104. Material 110 can be thick enough at the processing stage of FIG. 10 for particular applications. For other applications, it can be desired that a thicker amount of semiconductor material be provided. An exemplary thickness of material 110 is from about 10 Å to about 5000 Å. FIG. 11 shows fragment 100 after another pulse of semiconductor material is utilized to selectively form a layer 112 of semiconductor material over the layer 110. The conditions utilized for forming layer 112 can be similar to, or identical to, the conditions utilized for forming semiconductor material 110. Specifically, it is noted that semiconductor material 110 comprises a surface 111 of semiconductor material. Accordingly, the conditions described above with reference to FIGS. 6 and 7 can be utilized for selectively forming semiconductor material over surface 111 relative to the surface 105 of material 104. Layers 110 and 112 can be considered to have been formed by the pulse/purge cycle of FIG. 7. Such pulse/purge cycle can be repeated multiple times to deposit a desired thickness of semiconductor material. FIG. 12 shows construction 100 after a layer 114 of semiconductor material is selectively formed over layer 112 relative to surface 105 of material 104. Layers 110, 112 and 114 can comprise the same semiconductor material compositions as one another, or different compositions, and can be together considered to be a stack of semiconductor material layers. At least two of the layers will comprise different compositions relative to one another if different semiconductor material precursors, or semiconductor material precursor combinations, are utilized during formation of one of the layers than are utilized during formation of another of the layers. The layers 110, 112 and 114 can all be crystalline in particular aspects of the invention. Further, in some aspects of the invention layers 110, 112 and 114 can be epitaxially grown single crystal materials. FIGS. 13-17 illustrate another aspect of the invention. FIG. 13 shows a semiconductor wafer fragment 200 comprising a substrate 202, an isolation region 204 extending into the substrate, and a transistor gate 206 over the substrate. Substrate 202, isolation region 204 and transistor gate 206 can comprise the same compositions as discussed above with reference to FIG. 4 for substrate 22, isolation region 24 and transistor gate 26, respectively. Accordingly, substrate 202 can comprise, consist essentially of, or consist of monocrystalline semiconductor material, such as, for example, monocrystalline silicon; isolation region 204 can comprise, consist essentially of, or consist of silicon dioxide; and transistor gate 206 can comprise layers 208, 210 and 212 having identical compositions to layers 28, 30 and 32 described previously. An anisotropically etched sidewall spacer 214 is adjacent a sidewall of transistor gate 206, and can comprise an identical composition as discussed above for spacer 34 of FIG. 4. A conductively-doped diffusion region 216 extends within substrate 202 proximate gate 206, and can comprise an identical composition as the diffusion region 36 discussed above with reference to FIG. 4. In an exemplary aspect, substrate 202 comprises an upper surface 203 consisting essentially of, or consisting of semiconductor material; isolation region 204 comprises an upper surface 205 consisting essentially of or consisting of, for example, silicon dioxide; layer 212 comprises an upper surface 213 consisting essentially of, or consisting of, for example, silicon nitride, silicon dioxide and/or silicon oxynitride; and sidewall spacer 214 comprises a surface 215 consisting essentially of, or consisting of, for example, silicon nitride, silicon dioxide, and/or silicon oxynitride. Construction 200 can be exposed to the conditions discussed above with reference to FIGS. 6 and 7 to selectively grow semiconductive material over surface 203 relative to surfaces 205, 213 and 215. FIG. 14 shows construction 200 after growth of semiconductor material 220 selectively over surface 203. An upper surface of semiconductor material 220 can be utilized as a substrate in subsequent processing to form another semiconductor material 222 over material 220 as shown in FIG. 15. Additionally, an upper surface of semiconductor material 222 can be utilized as a substrate for selectively forming another semiconductor material 224 as shown in FIG. 16. The layers 220, 222 and 224 can all be crystalline in particular aspects of the invention, and in some aspects can be epitaxially grown single crystal materials. The structure 200 of FIG. 16 advantageously has a substantially square outer corner 230 at the region where the problematic rounded corner 40 occurred in the prior art structure of FIG. 5. Accordingly, the problems discussed above relative to FIG. 5 can be alleviated, and in particular aspects even entirely overcome, utilizing the processing of the present invention. The structure of FIG. 16 shows semiconductor materials 220, 222 and 224 as separate distinct layers from one another. As discussed previously, the invention includes processing in which the multiple layers formed through sequential pulse/purge cycles of the type described with reference to FIG. 7 have different compositions relative to one another, and such would form a structure of the type formed in FIG. 16. However, as was also discussed above, the invention encompasses processes in which the multiple pulse/purge cycles of the type described with reference to FIG. 7 form layers having the same composition as one another. In such aspect, the layers 220, 222 and 224 of FIG. 16 would not be distinguishable from one another in the structure of FIG. 16. FIG. 17 shows construction 200 at the processing stage of FIG. 16 in an aspect in which layers 220, 222 and 224 of FIG. 16 have the same composition as one another and merge to form a single semiconductor material 240. FIG. 17 also illustrates another exemplary advantageous aspect of the present invention in which there has been lateral overgrowth of semiconductor material 240 over isolation region 204. Such lateral overgrowth can help to reduce p-channel degradation relative to transistor devices lacking the overgrowth. The invention described herein can provide numerous advantages relative to prior art processes. For instance, the invention can reduce the faceting described with reference to FIG. 5; can increase lateral overgrowth of a semiconductor material as described above with reference to FIG. 17; can reduce processing time due to removal of etchant, or decreasing of etchant concentration relative to prior art processes; can increase the robustness of processes by removing the etchant that prior art processing was undesirably sensitive to; and can increase selectivity for semiconductor formation over semiconductor surfaces relative to other surfaces by substantially avoiding, and in some cases entirely avoiding, detectable growth of semiconductor materials on undesired surfaces, such as, for example, surfaces comprising silicon nitride, silicon dioxide, and/or silicon oxynitride. 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. | <SOH> BACKGROUND OF THE INVENTION <EOH>There are numerous applications in which it is desired to selectively deposit semiconductor material onto a semiconductor surface relative to other surfaces. For instance, it can be desired to epitaxially form one or both of silicon and germanium on a semiconductor surface. A prior art method of epitaxially forming semiconductor material over a semiconductor surface is described with reference to FIGS. 1-3 . FIG. 1 shows a semiconductor wafer fragment 10 at a preliminary processing stage. Fragment 10 comprises a semiconductor substrate 12 . Substrate 12 can comprise, consist essentially of, or consist of monocrystalline silicon. The silicon can be appropriately doped with one or more conductivity-enhancing dopants. For instance, the silicon can be lightly background doped with p-type dopant, and can comprise various conductively-doped diffusion regions (not shown) formed therein. To aid in interpretation of the claims that follow, the terms “semiconductive substrate” and “semiconductor substrate” are defined to mean any construction comprising semiconductive material, including, but not limited to, bulk semiconductive materials such as a semiconductive wafer (either alone or in assemblies comprising other materials thereon), and semiconductive material layers (either alone or in assemblies comprising other materials). The term “substrate” refers to any supporting structure, including, but not limited to, the semiconductive substrates described above. The term “semiconductor material” refers to a material comprising one or more of the semiconductive elements, such as, for example, a material comprising one or both of silicon and germanium. An electrically insulative material 14 is formed over substrate 12 . Material 14 can comprise, consist essentially of, or consist of silicon and one or both of oxygen and nitrogen. For instance, material 14 can comprise silicon dioxide, silicon nitride, and/or silicon oxynitride. In the illustrated example, substrate 12 has an upper surface 13 , and material 14 is formed directly against (i.e., in physical contact with) the upper surface 13 . Material 14 is patterned to have a gap 16 extending therethrough to the upper surface 13 of substrate 12 . Material 14 has exposed surfaces 15 . Referring to FIG. 2 , a semiconductor material 18 is formed within gap 16 and also over the surfaces 15 of insulative material 14 . Material 16 will typically comprise, consist essentially of, or consist of one or both of silicon and germanium. If material 16 comprises, consists essentially of, or consists of silicon, such material can be formed utilizing dichlorosilane, H 2 and HCl. The dichlorosilane provides a silicon source. The H 2 participates in the silicon deposition, and also can remove undesired oxides forming over the growing silicon. The HCl etches material 18 before the material can form a uniform layer over insulative material 14 . Specifically, the material 18 nucleates over insulative material 14 to form small islands on surface 15 , as shown. The HCl continuously etches material 18 from the small islands, and accordingly removes material 18 from the islands before the islands can merge to form a continuous layer. The HCl is also thought to remove material 18 which is growing over surface 13 (the shown material 18 within gap 16 ), but such removal is too slow to prevent the layer of material 18 from forming within gap 16 . Accordingly, the HCl effectively creates a selective deposition of material 18 over the surface 13 of semiconductor material 12 relative to the surfaces 15 of insulative material 14 . The HCl can be replaced with Cl 2 in some aspects of the prior art. FIG. 3 shows construction 10 at the conclusion of the epitaxial growth, and shows that the semiconductor material 18 has been selectively formed over surface 13 of semiconductor substrate 12 relative to surfaces 15 of insulative material 14 . A problem with the processing of FIGS. 1-3 is that the utilization of HCl significantly slows the rate of deposition of semiconductor material 18 relative to a rate which would occur in the absence of the HCl. Accordingly, it is desired to develop deposition processes which can selectively form a semiconductor material over an exposed semiconductor substrate surface relative to exposed surfaces of non-semiconductor materials, and which have a higher rate than the processing sequence of FIGS. 1-3 . The processing sequence of FIGS. 1-3 is an exemplary prior art process. Other processes have been developed which are modifications of the process described with reference to FIGS. 1-3 . For instance, in one modification a semiconductor precursor (such as, for example, dichlorosilane) is provided in combination with H 2 to form semiconductor material 18 over a surface of a semiconductor substrate and over surfaces of insulative materials. After the growth of the semiconductor material, HCl is provided to selectively remove the semiconductor material from over the insulative materials surfaces while leaving a layer of the semiconductor material over the semiconductor substrate surface. In some aspects, the cycling of deposition of semiconductor material, etching of semiconductor material from over insulative material surfaces, deposition of the material, etching of the material, etc., is repeated multiple times to form a semiconductor material to a desired thickness over a semiconductor substrate surface. A particular prior art methodology flows disilane for about 10 seconds, then Cl 2 for about 10 seconds, then H 2 for about 10 seconds, and repeats the process multiple times to form a semiconductor layer to a desired thickness over a semiconductor substrate surface. FIGS. 4 and 5 illustrate another exemplary prior art application for selective formation of epitaxially-grown semiconductor material over a semiconductor substrate. Referring initially to FIG. 4 , a wafer fragment 20 comprises a substrate 22 . Substrate 22 can comprise the same construction as described previously relative to substrate 12 of FIG. 1 , and accordingly can comprise monocrystalline silicon lightly-background doped with p-type dopant. Substrate 22 comprises an upper surface 23 . An isolation region 24 extends within substrate 22 . Isolation region 24 can comprise, for example, a shallow trench isolation region, and accordingly can comprise silicon dioxide. Isolation region 24 comprises an upper surface 25 . A transistor gate 26 is formed over surface 23 of substrate 22 . Transistor gate 26 comprises an insulative material 28 , a conductive material 30 , and an insulative cap 32 . Insulative material 28 can comprise, for example, silicon dioxide, and can be referred to as pad oxide. Conductive material 30 can comprise, for example, one or more of metal, metal compounds and conductively-doped semiconductor material (such as, for example, conductively-doped silicon). Insulative cap 32 can comprise, consist essentially of, or consist of silicon together with one or both of oxygen and nitrogen. For instance, insulative cap 32 can comprise, consist essentially of, or consist of silicon dioxide, silicon nitride, or silicon oxynitride. Insulative cap 32 comprises an upper exposed surface 33 . An anisotropically-etched sidewall spacer 34 is along a sidewall of transistor gate 26 . Spacer 34 can comprise, consist essentially of, or consist of silicon together with one or both of oxygen and nitrogen. Accordingly, spacer 34 can comprise, or consist essentially of, or consist of one or more of silicon dioxide, silicon nitride and silicon oxynitride. Spacer 34 has an exposed surface 35 . A conductively-doped diffusion region 36 extends within substrate 22 beside transistor gate 26 . The conductively-doped diffusion region 36 and transistor gate 26 can be together incorporated into a transistor device. Referring to FIG. 5 , a semiconductor material 38 is formed over surface 23 of semiconductor substrate 22 selectively relative to surfaces 25 and 33 of insulative materials 24 and 32 , respectively. Semiconductor material 38 can comprise, consist essentially of, or consist of one or both of silicon and germanium, and can be formed utilizing processing analogous to that described previously with reference to FIGS. 1-3 . Accordingly, the semiconductor material can be formed by deposition from a semiconductor precursor in combination with an etch which removes the deposited material from over surfaces 25 and 33 while leaving the material over surface 23 . An undesired consequence of the etch is that such rounds an outer corner of deposited material 38 , as can be seen at a location 40 in the diagram of FIG. 5 . The rounded outer corner can be referred to as a faceted corner, and can increase degradation of a transistor device component (with a common effect being p-channel degradation), and can also adversely affect an implant profile if a dopant is implanted either into or through semiconductor material 38 . For instance, conductively-doped diffusion region 36 would sometimes be formed by an implant subsequent to formation of material 38 rather than being present prior to deposition of semiconductor material 38 . The rounded faceted corner 40 could then adversely affect formation of the diffusion region 36 . The semiconductor material 38 of FIG. 5 can ultimately be conductively doped, and can be incorporated into, for example, an elevated source/drain region associated with a transistor device comprising gate 26 . Numerous problems are encountered during the processing described above with reference to FIGS. 1-5 . Such problems include the faceted corner 40 and slow growth rate discussed previously. Another problem is that the deposition rate and quality can be sensitive to the amount of etchant (such as, for example, HCl) utilized during the deposition/etch processing, which can make it problematic to control wafer throughput and quality in a fabrication process. For instance, it is sometimes found that increasing HCl flow by 10% will decrease the growth rate of a deposited semiconductor material by about 20%. It would be desirable to develop deposition methods which alleviate, and preferably eliminate, some or all of the above-discussed problems. | <SOH> SUMMARY OF THE INVENTION <EOH>In one aspect, the invention encompasses a method for deposition of semiconductor material. A substrate is provided within a reaction chamber. The substrate includes a first material and a second material, with the second material having a different composition than the first material. The first and second materials are exposed to a semiconductor material precursor under conditions in which growth of semiconductor material from the precursor comprises a lag phase prior to a growth phase. The conditions are also such that it takes longer for the growth phase to initiate on the second material than on the first material. A concentration of the precursor is pulsed into the chamber. The duration of the pulse is long enough for the growth phase to substantially occur on the first material, but not long enough for the growth phase to substantially occur on the second material. In one aspect, the invention encompasses a method for deposition of a semiconductor material comprising one or both of silicon and germanium. A substrate is provided within a reaction chamber. The substrate has a first surface consisting essentially of one or more semiconductor materials and a second surface consisting of one or more electrically insulative materials. The first and second surfaces are exposed to at least one precursor selected from the group consisting of silicon-containing precursors and germanium-containing precursors to deposit a substance comprising one or both of silicon and germanium over the substrate. The exposure is under conditions in which deposition of the substance over the first and second surfaces comprises nucleation phase/growth phase dynamics, and under which it takes longer for the growth phase to initiate over the second surface than over the first surface. The exposure is conducted for a time long enough to substantially initiate the growth phase over the first surface but not long enough to substantially initiate the growth phase over the second surface. Thus, the substance is selectively formed over the first surface relative to the second surface. | 20040109 | 20060117 | 20050714 | 65977.0 | 1 | ANYA, IGWE U | METHODS FOR DEPOSITION OF SEMICONDUCTOR MATERIAL | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,755,047 | ACCEPTED | Light emission device | A light emission device. A lead frame comprises a first lead frame segment and a second lead frame segment. A light source is coupled to the first lead frame segment. A wire bond is coupled to the light source and coupled to the second lead frame segment. A translucent epoxy cast encases the light source, the wire bond and a portion of the lead frame. | 1. A light emission device comprising: a lead frame comprising a first lead frame segment and a second lead frame segment; a light source coupled to said first lead frame segment; a wire bond coupled to said light source and coupled to said second lead frame segment; and an epoxy cast encasing said light source, said wire bond, and a portion of said lead frame. 2. The light emission device as recited in claim 1 wherein said first lead frame segment comprises a first recess such that said light source resides at least partially within said first recess. 3. The light emission device as recited in claim 1 wherein said first lead frame segment comprises a second recess such that said epoxy cast is anchored to said first lead frame segment. 4. The light emission device as recited in claim 2 wherein said first recess is a reflector cup. 5. The light emission device as recited in claim 1 wherein said epoxy cast comprises a shaped epoxy portion. 6. The light emission device as recited in claim 1 wherein said lead frame comprises plating. 7. The light emission device as recited in claim 1 wherein said epoxy cast comprises a color tinting. 8. The light emission device as recited in claim 1 wherein said epoxy cast is operable to diffuse light from said light source. 9. The light emission device as recited in claim 1 further comprising a second wire bond coupled to said first lead frame segment and said light source. 10. The light emission device as recited in claim 5 wherein said shaped epoxy portion is a dome shape. 11. The light emission device as recited in claim 1 wherein said light source is a light emitting diode die. 12. A method for generating a light emission device, said method comprising: coupling a light source to a first lead frame segment of a lead frame, said lead frame further comprising a second lead frame segment; coupling a wire bond to said light source and said second lead frame segment; and encasing said light source, said wire bond, and a portion of said lead frame in an epoxy cast. 13. The method as recited in claim 12 wherein said first lead frame segment comprises a first recess such that said light source resides at least partially within said first recess. 14. The method as recited in claim 13 wherein said first recess is a reflector cup. 15. The method as recited in claim 12 wherein said encasing comprises forming a shaped portion of said epoxy cast. 16. The method as recited in claim 12 further comprising dying said epoxy cast with a color tinting. 17. The method as recited in claim 12 further comprising diffusing at least a portion of said translucent epoxy cast. 18. The method as recited in claim 12 further comprising coupling a second wire bond to said first lead frame segment and said light source. 19. The method as recited in claim 12 wherein said light source is a light emitting diode die. 20. A light emission device comprising: a lead frame comprising a first lead frame segment and a second lead frame segment; a light emitting diode coupled to said first lead frame segment, said first lead frame segment comprising a first recess such that said light source resides at least partially within said first recess; a wire bond coupled to said light source and coupled to said second lead frame segment; and an epoxy cast encasing said light emitting diode, said wire bond, and a portion of said lead frame, said epoxy cast comprising a shaped epoxy portion. 21. The light emission device as recited in claim 20 wherein said first lead frame segment comprises a second recess such that said epoxy cast is anchored to said first lead frame segment. 22. The light emission device as recited in claim 20 wherein said first recess is a reflector cup. 23. The light emission device as recited in claim 20 wherein said shaped epoxy portion is incident to said light source. 24. The light emission device as recited in claim 20 wherein said lead frame comprises plating. 25. The light emission device as recited in claim 20 wherein said epoxy cast comprises a color tinting. 26. The light emission device as recited in claim 20 wherein said epoxy cast is operable to diffuse light from said light source. 27. The light emission device as recited in claim 20 further comprising a second wire bond coupled to said first lead frame segment and said light source. 28. The light emission device as recited in claim 20 wherein said shaped epoxy portion is a dome shape. | FIELD OF INVENTION Various embodiments of the present invention relate to the field of light emission devices. BACKGROUND OF THE INVENTION Light emitting diodes (LEDs) are display devices that use a semiconductor diode that emits light when charged with electricity. LEDs provide light in a wide array of electronic devices. For example, LEDs are used as on/off indicators in electronic devices, are used to provide LCD or keypad backlighting in handheld devices, such as personal digital assistants (PDAs) and cellular telephones, and are used for digital display readouts, such as electronic signs. Typically, LEDs are manufactured into an electronic chip (e.g., LED chips) that provide for easy integration into electronic devices. Conventional LED chips employ surface mount technology (SMT) using a printed circuit board (PCB) as a base, with the LED die encapsulated into an epoxy resin. The encapsulating process typically used is transfer molding, which utilizes high temperature and pressure to melt the mold compound and force it into the mold cavity. Due to the use of SMT and transfer molding epoxy encapsulation, there are a number of problems inherent to the used of conventional LED chips. Typical LED chips are subject to thermal breakdown as a result of the poor thermal dissipation properties of a typical PCB. Due to the poor heat dissipation of a typical PCB, an LED used in a high power or high brightness application, may fail. Therefore, typical LED chips are restricted to low power or brightness, or have short life spans. Furthermore, an encapsulating process using transfer molding creates an epoxy molding over an LED on top of a PCB. An LED chip subjected to the elements is prone to delamination caused by moisture absorption. Delamination causes the epoxy molding to separate from the PCB, exposing the LED die to moisture, and eventually leading to failure. Due to the wide number of electronic devices using LEDs that are exposed to the elements, delamination is a wide problem. Moreover, transfer molding requires expensive tools, machines and materials, requiring a substantial investment that is not typically viable for small- and medium-scale production. SUMMARY OF THE INVENTION Various embodiments of the present invention, a light emission device and a method for generating a light emission device, are described herein. In one embodiment, the light emission device comprises a lead frame comprising a first lead frame segment and a second lead frame segment. A light source is coupled to the first lead frame segment. A wire bond is coupled to the light source and coupled to the second lead frame segment. A translucent epoxy cast encases the light source, the wire bond and a portion of the lead frame. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention: FIG. 1 illustrates a side view of a light emission device in accordance with an embodiment of the present invention. FIG. 2 illustrates a side view of a light emission device in accordance with another embodiment of the present invention. FIG. 3 illustrates an isometric view of a lead frame of a light emission device in accordance with an embodiment of the present invention. FIG. 4 illustrates a cut-away cross-sectional view of a light emission device in accordance with an embodiment of the present invention. FIG. 5A illustrates a cut-away side view of a light emission device including a round shape epoxy dome in accordance with an embodiment of the present invention. FIG. 5B illustrates a top view of a light emission device including a round shape epoxy dome in accordance with an embodiment of the present invention. FIG. 6A illustrates a cut-away side view of a light emission device including an oval shape epoxy dome in accordance with an embodiment of the present invention. FIG. 6B illustrates a top view of a light emission device including an oval shape epoxy dome in accordance with an embodiment of the present invention. FIG. 7 illustrates a side view of a light emission device including a hemispherical reflector cup in accordance with an embodiment of the present invention. FIG. 8 illustrates side view of a light emission device including a flat top epoxy surface and including a first wire bond and a second wire bond in accordance with an embodiment of the present invention. FIG. 9 is a flow chart illustrating a process for generating a light emission device in accordance with an embodiment of the present invention. BEST MODE(S) FOR CARRYING OUT THE INVENTION Reference will now be made in detail to various embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with various embodiments, it will be understood that they are not intended to limit the invention to these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and the scope of the invention as defined by the appended claims. Furthermore, in the following detailed description of the present invention, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components, structures and devices have not been described in detail so as to avoid unnecessarily obscuring aspects of the present invention. FIG. 1 illustrates a side view of an exemplary light emission device 100 in accordance with an embodiment of the present invention. Light emission device 100 comprises light source 105, wire bond 110, and a lead frame comprising first lead frame segment 115 and second lead frame segment 120. Light source 105, wire bond 110 and at least a portion of the lead frame are encased in epoxy cast 125. It should be appreciated that a lead frame refers to a type of chip package that uses conductive leads that extend outside of a housing. In the present embodiment, a portion of first lead frame segment 115 and a portion of second lead frame segment 120 are not encased within epoxy cast 125, allowing for the transmission of power signals to light source 105. In one embodiment, the lead frame is comprised of copper, however, it should be appreciated that any other conductive material, such as another metal, may be implemented. In one embodiment, the lead frame is covered in a plating to improve various properties of the lead frame. For example, plating may be used to improve the bonding strength between light source 105 and first lead frame segment 115 and between wire bond 110 and second lead frame segment 120, may enhance the adhesiveness of epoxy cast 125 to the lead frame, may prevent oxidization of a metal lead frame, may enhance to solderability of pads of first lead frame segment 115 and second lead frame segment 120, and can improve the surface reflectivity to enhance flux extraction. In one embodiment, the plating is nickel/palladium/gold (NiPdAu). In another embodiment, the plating is silver (Ag). It should be appreciated that any other plating material may be implemented depending on the design requirements of light emission device 100. A lead frame provides improved thermal dissipation over the use of a PCB substrate, due to the lower thermal resistance. Light emission device 100 can be subjected to higher operating current due to the better heat dissipation properties of the lead frame. Therefore, the luminous intensity of light emission device 100 can be increased. Furthermore, light emission device 100 may have a lower profile due to a lead frame being thinner than a PCB substrate. Light source 105 is coupled to first lead frame segment 115. In one embodiment, a power signal is received at light source 105 from first lead frame segment 115. In one embodiment, light source 105 is a light emitting diode (LED) die. While embodiments of the invention are described using an LED, it should be appreciated that other types of light sources may be implemented, such as an infrared emitting diode (IRED) or a laser diode. Wire bond 110 is coupled to light source 105 and second lead frame segment 120. Light source 105 receives positive and negative power signals via first lead frame segment 115 and wire bond 110, and emits light in response to such signals. In one embodiment, wire bond 110 is a gold wire. However, it should be appreciated than any conductive material may be implemented at wire bond 110. In one embodiment, first lead frame segment 115 operates as a cathode for transmitting a negative power signal, and second lead frame 120 operates as an anode for transmitting a positive power signal, as indicated at anode mark 130. Epoxy cast 125 is formed over light source 105, wire bond 110, a portion of first lead frame segment 115 and an portion of second lead frame segment 120 using an epoxy casting process. The use of a conductive lead frame substrate provides for the use of a conventional casting process in forming epoxy cast 125. In one embodiment, epoxy cast 125 is comprised of substantially half epoxy resin and substantially half epoxy hardener. However, it should be appreciated that any combination of epoxy resin and epoxy hardener may be used. Epoxy cast 125 is translucent, allowing for the passage of light. In one embodiment, epoxy cast 125 comprises a color tinting for filtering the wavelength of light passing through epoxy cast 125. In one embodiment, epoxy cast 125 is operable to diffuse light passing through epoxy cast 125. Using a casting process to generate epoxy cast 125 provides a substantial cost savings over transfer molding process due to the high volume per run with high density lead frame design as well as lower initial tooling costs. Furthermore, epoxy cast 125 provides improved moisture absorption resistivity compared to molding compound which is more sensitive to moisture. FIG. 2 illustrates a side view of light emission device 200 in accordance with another embodiment of the present invention. Light emission device 200 comprises light source 205, wire bond 210, and a lead frame comprising first lead frame segment 215 and second lead frame segment 220. Light source 205, wire bond 210 and at least a portion of the lead frame are encased in epoxy cast 225. Light emission device 200 is similar to light emission device 100 of FIG. 1, while providing additional features. Light emission device 200 comprises recess 235 for receiving light source 205 such that light source 205 resides at least partially within recess 235. Placing light source 205 within recess 235 assists in providing a low profile for light emission device 200, thereby allowing wider applicability. Light source 205 is coupled to first lead frame segment 215 and wire bond 210, and wire bond 210 is also coupled to second lead frame segment 220. Light source 205 receives positive and negative power signals via first lead frame segment 215 and wire bond 210, and emits light in response to such signals. In one embodiment, first lead frame segment 215 operates as a cathode for transmitting a negative power signal, and second lead frame 220 operates as an anode for transmitting a positive power signal, as indicated at anode mark 230. With reference to FIG. 3, an isometric view of the lead frame of light emission device 200 is illustrated, in accordance with an embodiment of the present invention. Recess 235 is configured for receiving a light source (e.g., light source 205 of FIG. 2). With reference to FIG. 2, the lead frame of light emission device 200 also comprises at least one anchoring recess for allowing epoxy cast 225 to be anchored to first lead frame segment 215 and second lead frame segment 220. In one embodiment, first lead frame segment 215 comprises anchoring recess 250, such that during epoxy casting, anchoring recess 250 is filled such that epoxy cast 225 is anchored to first lead frame segment 215. FIG. 4 illustrates a cut-away cross-sectional view of light emission device 200 of FIG. 2, in accordance with an embodiment of the present invention. The cut-away cross-sectional view of FIG. 4 shows the cross-sectional area of light emission device 200 at dotted line 280 of FIGS. 2 and 3. As shown in FIG. 4, the illustrated portion of first lead frame segment 215 is completely surrounded by epoxy cast 225. In particular, anchoring recess 250 is completely filled with epoxy cast 225. With reference to FIG. 2, first lead frame segment 215 also comprises anchoring recesses 245 and 255, and second lead frame segment 220 comprises anchoring recesses 240 and 260. Anchoring recesses 240, 245, 255 and 260 provide additional anchoring functionality to the lead frame, thereby providing increased anchorage between the lead frame and epoxy cast 225. With reference to FIG. 3, first lead frame segment 215 also comprises anchoring extensions 265 and 270, providing additional anchoring functionality by locking epoxy casting 225 to first lead frame segment 215. It should be appreciated that first lead frame segment 215 and second lead frame segment 220 may comprise any number of anchoring recesses and anchoring extensions, and that those illustrated in FIGS. 2, 3 and 4 are exemplary. Improving the anchorage between the lead frame and epoxy cast 225 prevents delamination due to operation of light emission device 200 under a wide range of environmental conditions. In various embodiments of the present invention, a portion of the epoxy cast may be formed into a shape, such as a dome, for directing light. FIG. 5A illustrates a cut-away side view of a light emission device 500 including a round shape epoxy dome in accordance with an embodiment of the present invention. Light emission device 500 comprises light source 505, wire bond 510, and a lead frame comprising first lead frame segment 515 and second lead frame segment 520. Light source 505, wire bond 510 and at least a portion of the lead frame are encased in epoxy cast 525. Epoxy cast 525 comprises epoxy shaped portion 530. In the illustrated embodiment, shaped portion 530 is a round shape dome. It should be appreciated that epoxy shaped portion 530 may be any shape (e.g., rectangular, triangular, cylindrical), and is not limited to the illustrated embodiment. FIG. 5B illustrates a top view of light emission device 500 including a round shape epoxy dome in accordance with an embodiment of the present invention. As shown in FIG. 5B, epoxy shaped portion 530 is seen to provide for symmetric viewing angles of emitted light in all directions. FIG. 6A illustrates a cut-away side view of a light emission device 600 including an oval shape epoxy dome in accordance with an embodiment of the present invention. Light emission device 600 comprises light source 605, wire bond 610, and a lead frame comprising first lead frame segment 615 and second lead frame segment 620. Light source 605, wire bond 610 and at least a portion of the lead frame are encased in epoxy cast 625. Epoxy cast 625 comprises epoxy shaped portion 630. In the illustrated embodiment, shaped portion 630 is an oval shape dome. As described at FIG. 5A, it should be appreciated that epoxy shaped portion 630 may be any shape, and is not limited to the illustrated embodiment. FIG. 6B illustrates a top view of light emission device 600 including an oval shape epoxy dome in accordance with an embodiment of the present invention. As shown in FIG. 6B, epoxy shaped portion 630 is seen to provide for asymmetric viewing angles of emitted light in all directions. Using an oval shape dome, the viewing angle on the horizontal axis is greater than the viewing angle on the vertical axis. FIG. 7 illustrates a side view of light emission device 700 including a reflector cup 735 in accordance with an embodiment of the present invention. Light emission device 700 comprises light source 705, wire bond 710, and a lead frame comprising first lead frame segment 715 and second lead frame segment 720. Light source 705, wire bond 710 and at least a portion of the lead frame are encased in epoxy cast 725. Light emission device 700 is similar to light emission device 100 of FIG. 1, while providing additional features. Light emission device 700 comprises reflector cup 735 for receiving light source 705 and for reflecting light emitted from light source 705. In one embodiment, light source 705 resides at least partially within reflector cup 735. Placing light source 705 within reflector cup 735 allows for enhancing and directing the light emitted by light source 705. Furthermore, placing light source 705 within reflector cup 735 assists in providing a low profile for light emission device 700, thereby allowing wider applicability. Epoxy cast 725 comprises epoxy shaped portion 730. In the illustrated embodiment, shaped portion 730 is a round shape dome. It should be appreciated that epoxy shaped portion 730 may be any shape and is not limited to the illustrated embodiment. The use of reflector cup 735 in conjunction with epoxy shaped portion 730 allows for directing the light emitted in a desired radiation pattern and viewing angle. As described above, embodiments of the present invention are configured to implement different types of light sources. For example, embodiments of the present invention may implement a double wire bonded light source (e.g., a double wire bonded LED). A double wire bonded light source is operable to receive positive and negative power signals through two wire bonds, respectively, rather than through one wire bond and through coupling the light source to a lead frame. FIG. 8 illustrates a side view of light emission device 800 including first wire bond 810 and second wire bond 830 in accordance with an embodiment of the present invention. Light emission device 800 comprises light source 805, first wire bond 810, second wire bond 830 and a lead frame comprising first lead frame segment 815 and second lead frame segment 820. Light source 805, wire bond 810 and at least a portion of the lead frame are encased in epoxy cast 825. In one embodiment, epoxy cast 825 has a flat top surface. It should be appreciated that a lead frame refers to a type of chip package that uses conductive leads that extend outside of a housing. First wire bond is coupled to light source 805 and second lead frame segment 820 and second wire bond 830 is coupled to light source 805 and first lead frame segment 815. FIG. 9 is a flow chart illustrating a process 900 for generating a light emission device in accordance with an embodiment of the present invention. For purposes of clarity, the following discussion will refer to FIG. 2 to more clearly describe the present invention. However, it should be appreciated that other embodiments of the present invention may be generated according to process 900. Although specific steps are disclosed in process 900, such steps are exemplary. That is, the embodiments of the present invention are well suited to performing various other steps or variations of the steps recited in FIG. 9. At step 910 of process 900, light source 205 is coupled to first lead frame segment 215 of a lead frame, wherein the lead frame also includes second lead frame segment 220. In one embodiment, light source 205 is an LED die. In one embodiment, first lead frame segment 215 comprises a first recess 235 such that light source 205 resides at least partially within first recess 235. In one embodiment, first recess 235 is a reflector cup (e.g., reflector cup 735 of FIG. 7). At step 920, a wire bond is coupled to light source 205 and second lead frame segment 220. In one embodiment, as shown at step 925, a second wire bond (e.g., second wire bond 830 of FIG. 8) is coupled to first lead frame 215 and light source 205. It should be appreciated that step 925 is used when light source 205 is a double wire bonded light source. Accordingly, step 925 is optional. At step 930, light source 205, wire bond 210, and a portion of lead frame are encased in translucent epoxy cast 225. In one embodiment, as shown at step 940, a shaped portion (e.g., shaped portion 530 of FIG. 5) of translucent epoxy cast 225 is formed. In one embodiment, the shaped portion is formed incident light source 205. In one embodiment, as shown at step 950, translucent epoxy cast 225 is dyed with a color tinting. In one embodiment, translucent epoxy cast 225 is configured to act as a diffuser. Embodiments of the invention provide a light emission device that provides higher operating conditions with better heat dissipation. Furthermore, the light emission device has improved reliability and package robustness due to the use of a lead frame and an epoxy casting process, as well as providing better anchorage between the lead frame and the epoxy cast. Moreover, the lead frame can be etched or stamped into a desirable shape, and can provide a thinner package profile. The described embodiments also provide a light emission device that provides higher light output due to the improved heat dissipation, as well as a higher reflective surface, a reflector cup, and a shaped epoxy dome. Various embodiments of the present invention, a light emission device, are thus described. While the present invention has been described in particular embodiments, it should be appreciated that the present invention should not be construed as limited by such embodiments, but rather construed according to the below claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>Light emitting diodes (LEDs) are display devices that use a semiconductor diode that emits light when charged with electricity. LEDs provide light in a wide array of electronic devices. For example, LEDs are used as on/off indicators in electronic devices, are used to provide LCD or keypad backlighting in handheld devices, such as personal digital assistants (PDAs) and cellular telephones, and are used for digital display readouts, such as electronic signs. Typically, LEDs are manufactured into an electronic chip (e.g., LED chips) that provide for easy integration into electronic devices. Conventional LED chips employ surface mount technology (SMT) using a printed circuit board (PCB) as a base, with the LED die encapsulated into an epoxy resin. The encapsulating process typically used is transfer molding, which utilizes high temperature and pressure to melt the mold compound and force it into the mold cavity. Due to the use of SMT and transfer molding epoxy encapsulation, there are a number of problems inherent to the used of conventional LED chips. Typical LED chips are subject to thermal breakdown as a result of the poor thermal dissipation properties of a typical PCB. Due to the poor heat dissipation of a typical PCB, an LED used in a high power or high brightness application, may fail. Therefore, typical LED chips are restricted to low power or brightness, or have short life spans. Furthermore, an encapsulating process using transfer molding creates an epoxy molding over an LED on top of a PCB. An LED chip subjected to the elements is prone to delamination caused by moisture absorption. Delamination causes the epoxy molding to separate from the PCB, exposing the LED die to moisture, and eventually leading to failure. Due to the wide number of electronic devices using LEDs that are exposed to the elements, delamination is a wide problem. Moreover, transfer molding requires expensive tools, machines and materials, requiring a substantial investment that is not typically viable for small- and medium-scale production. | <SOH> SUMMARY OF THE INVENTION <EOH>Various embodiments of the present invention, a light emission device and a method for generating a light emission device, are described herein. In one embodiment, the light emission device comprises a lead frame comprising a first lead frame segment and a second lead frame segment. A light source is coupled to the first lead frame segment. A wire bond is coupled to the light source and coupled to the second lead frame segment. A translucent epoxy cast encases the light source, the wire bond and a portion of the lead frame. | 20040108 | 20070227 | 20050714 | 69914.0 | 0 | SOWARD, IDA M | LIGHT EMISSION DEVICE | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,755,172 | ACCEPTED | Apparatus and methods for an underfilled integrated circuit package | Embodiments of the present invention include first and second substrate structures with underfill injected into a substrate structure interface through a feature of the substrate structure, a heat spreader, and the like. | 1. An apparatus comprising: a first substrate structure; a second substrate structure electrically coupled to the first substrate structure with at least one electrical connection, the at least one electrical connection located in a first portion of a substrate structure interface; and said second substrate structure further comprising at least one hole to allow an underfill material to be injected into a second portion of the substrate structure interface. 2. The apparatus of claim 1, wherein the first substrate structure includes a die and the second substrate structure includes a package substrate. 3. The apparatus of claim 1, wherein the underfill material is a selected one of a thermosetting resin and a thermoplastic. 4. The apparatus of claim 1, wherein the at least one electrical connection is a solder joint. 5. The apparatus of claim 4, wherein the at least one solder joint comprises at least a selected one of lead, tin, gold, silver, indium, bismuth, and copper. 6. The apparatus of claim 1, wherein the first and second portions of the substrate structure interface include substantially the entire substrate structure interface. 7. The apparatus of claim 1, wherein the at least one hole in the second substrate structure is located approximately under the center of the first substrate structure. 8. The apparatus of claim 1, further comprising: a heat spreader attached to the second substrate structure and thermally coupled to the first substrate structure. 9. An apparatus comprising: a first substrate structure; a second substrate structure electrically coupled to the first substrate structure with at least one electrical connection, the at least one electrical connection located in a first portion of a substrate structure interface; and a heat spreader attached to the second substrate structure and thermally coupled to the first substrate structure, the heat spreader having at least one hole to allow an underfill material to be injected into a second portion of the substrate structure interface. 10. The apparatus of claim 9, wherein the underfill material is a selected one of a thermosetting resin and a thermoplastic. 11. The apparatus of claim 9, wherein the at least one electrical connection is a solder joint. 12. The apparatus of claim 11, wherein the at least one solder joint comprises at least a selected one of lead, tin, gold, silver, indium, bismuth, and copper. 13. The apparatus of claim 9, wherein the first and second portions of the substrate structure interface include substantially the entire substrate structure interface. 14. The apparatus of claim 9, wherein the first substrate structure includes a die and the second substrate structure includes a package substrate. 15. A method comprising: forming an electrical interconnection between a first and second substrate structure by heating a solderable material, located substantially in a first portion of a substrate structure interface, to a reflow temperature; and injecting underfill material into a second portion of the substrate structure interface, before at least a selected one of the first and second substrate structure cools substantially below the reflow temperature. 16. The method of claim 15, wherein the injecting underfill material is done when at least a selected one of the first and second substrate structure is approximately between a solder solidification temperature and a component cracking temperature. 17. The method of claim 16, wherein the solder solidification temperature is approximately between 180 degrees Celsius (C.) and 230 degrees C. and the component cracking temperature is approximately 180 degrees C. 18. The method of claim 15, wherein injecting underfill material into a second portion of the substrate structure interface comprises injecting underfill material through at least one hole in the second substrate structure. 19. The method of claim 18, wherein the at least one hole in the second substrate structure is located approximately under the center of the first substrate structure. 20. The method of claim 15, further comprising: placing a heat spreader over the first substrate structure and attaching the heat spreader to the second substrate structure, the heat spreader to form a substantially sealed cavity surrounding the substrate structure interface; and injecting underfill material until sealed cavity is substantially filled. 21. The method of claim 20, wherein injecting underfill material comprises injecting underfill material through at least one hole in the second substrate structure. 22. The method of claim 20, wherein injecting underfill material comprises injecting underfill material through at least one hole in the heat spreader. 23. The method of claim 15, further comprising: temporarily placing a chuck over the first substrate structure to form a substantially sealed cavity surrounding the substrate structure interface; and injecting underfill material, through at least one hole in the chuck, until the sealed cavity is substantially filled. 24. The method of claim 23, wherein the chuck heats the first substrate structure. 25. A system comprising: an integrated circuit, wherein the integrated circuit is housed in a package including: a first substrate structure electrically coupled to a second substrate structure with at least one electrical connection located in a first portion of a substrate structure interface; and the second substrate structure having at least one hole to allow the an underfill material to be injected into a second portion of the substrate structure interface; a dynamic random access memory coupled to the integrated circuit; and an input/output interface coupled to the integrated circuit. 26. The system of claim 25, wherein the integrated circuit is a microprocessor. 27. The system of claim 26 wherein the system is a selected one of a set-top box, an entertainment unit, and a digital versatile disk player. 28. The system of claim 25, wherein the input/output interface comprises a networking interface. 29. A system comprising: an integrated circuit, wherein the integrated circuit is housed in a package including: a first substrate structure electrically coupled to a second substrate structure with at least one electrical connection located in a first portion of a substrate structure interface; and a heat spreader attached to the second substrate structure and thermally coupled to the first substrate structure, the heat spreader having at least one hole to allow an underfill material to be injected into a second portion of the substrate structure interface; a dynamic random access memory coupled to the integrated circuit; and an input/output interface coupled to the integrated circuit. 30. The system of claim 29, wherein the integrated circuit is a microprocessor. 31. The system of claim 30, wherein the system is a selected one of a set-top box, an audio/video controller, and a DVD player. 32. The system of claim 29, wherein the input/output interface comprises a networking interface. | FIELD OF THE INVENTION The present invention relates to the field of integrated circuits, and more particularly, to an integrated circuit package adapted to receive underfill injected at near die-attach temperatures, and a process to make the same. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a cross-sectional view of an IC package, in accordance with one embodiment of this invention; FIG. 2 is a cross-sectional view of an underfill process, in accordance with an embodiment of this invention; FIG. 3 is a graphical representation of process cycles as a function of time and temperature, in accordance with an embodiment of this invention; FIG. 4 is a cross-sectional view of an IC package with an integrated heat spreader, in accordance with an embodiment of this invention; FIG. 5 is a cross-sectional view of an IC package underfill process, in accordance with an embodiment of this invention; and FIG. 6 is a block diagram of a system including an IC package, in accordance with one embodiment of this invention. DETAILED DESCRIPTION Parts of the description will be presented in terms commonly employed by those skilled in the art to convey the substance of their work to others skilled in the art. For purposes of explanation, specific processes, materials, and configurations are set forth in order to provide a thorough understanding of the illustrated embodiments of the present invention. However, it will be apparent to one skilled in the art that embodiments of the present invention may be practiced without the specific details. In other instances, well-known features are omitted or simplified in order not to obscure the illustrated embodiments of the present invention. The phrase “in one embodiment” is used repeatedly. The phrase generally does not refer to the same embodiment; however, it may. The terms “comprising,” “having,” and “including” are synonymous, unless the context dictates otherwise. FIG. 1 shows an integrated circuit (IC) package 200 in accordance with an embodiment of the present invention. The IC package 200 may include a first substrate structure 201 attached to a second substrate structure 204 with solder bumps 202. The solder bumps are located in between the first and second substrate structures at an area known as the substrate structure interface. A dielectric underfill 208 may be added to the substrate structure interface to substantially surround the solder bumps. In one embodiment the IC package 200 may include a first substrate structure 201 that comprises a die and a second substrate structure 204 that includes a package substrate. In various embodiments the die 201 may be composed of silicon, silicon on sapphire, silicon germanium, gallium arsenide, or any other suitable materials. An integrated circuit may be fabricated on the die 201 (usually on or near the first die surface 201a) with the terminals of the integrated circuit substantially corresponding with the die pads 206 on the second die surface 201b. A low-k interlayer dielectric (ILD) 209 may be used to insulate adjacent conductive lines in the die 201. Dies may be fragile with extremely small terminals. Often one or more dies may be placed on a package substrate that provides protection, cooling, and more accessible electrical connections. This may be referred to as a die package. This die package may be attached to an interconnecting substrate that provides integration with components such as high-power resistors, mechanical switches, capacitors, etc., which may not be readily integrated onto a the die package. Examples of interconnecting substrates include, but are not limited to a printed circuit card (PCC) and a printed circuit board (PCB). Referring to FIG. 1, in various embodiments the first substrate structure 201 may represent a naked die, a package substrate, or an interconnecting substrate, while the second substrate structure 204 may represent the package substrate or an interconnecting substrate. The substrate structures of the IC package 200 are not limited to a particular material. Embodiments which use the substrate primarily for mechanical support and insulating purposes may include ceramic (thick-filmed, cofired, or thin-filmed), plastic, and glass; embodiments using the substrate to provide electrical functions may be composed of a wide variety of semiconductor and ferrite materials. The substrate structures may contain alternating conductive and dielectric layers in order to provide trace paths from one surface to the other. For example, in the embodiment depicted in FIG. 1 where the second substrate structure 204 includes a package substrate, conductive package pads 207 on a first package surface 204a may be electrically connected to a second package surface 204b by these traces. Solder bumps 202 may be arranged in a two-dimensional array at the substrate structure interface between the second die surface 201b and the first package surface 204a. The solder bumps 202 may comprise a lead-tin solder rich in lead. However, in other embodiments, solder bumps 202 may include various combinations of gold, copper, silver, lead, bismuth, indium, and tin. It may also be desirable for the solder metal to be as compliant as possible, i.e., a low yield strength, so that the solder deforms under relatively low loads without translating the associated stress to the die. Each of the solder bumps 202 may be substantially aligned between a corresponding die pad 206 and a package pad 207. The solder bumps 202 may be heated to a reflow temperature such that the solder 202 attaches to each of the pads. The reflow temperature may be just above the solidification temperature for a given solder composition. The package 200 may be allowed to cool to below the solidification temperature of the solder. As the solder solidifies it may form a solder joint that electrically and mechanically interconnects the first substrate structure 201 and the second substrate structure 204. The solder joint in this embodiment may be referred to as a controlled collapse chip connection (C4). Shortly after the package has cooled to below the solidification temperature of the solder, an underfill material 208 may be injected into the interface. The underfill is usually a type of thermosetting epoxy resin. The underfill may distribute the stress resulting from coefficient of thermal expansion (CTE) mismatches between the IC package components, and thereby reinforcing the C4 solder joints, first substrate structure 201, and the second substrate structure 204. In general, a cured thermosetting material is a cross-linked resin made up of resin, crosslinker, catalyst, fillers, and other components for adhesion and flow. Cross-linking is the attachment of polymer chains by bridges of an element, a molecular group, or a compound, and in thermosets, will occur upon heating. Curing of thermosets may be difficult to reverse because of this structural change of the molecules. Because the underfill is injected at a high temperature, the thermosetting material may cross-link quickly, inhibiting the flow of the material under the die. Depending on the curing profile of the underfill composition, cross-linking can take place from anywhere between 80 and 170 degrees Celsius (C). This resistance may be overcome by exerting external pressure by injecting the underfill material. Using external pressure of the injection process may allow the underfill to be quickly dispersed throughout the entire bumped region, before the resin has a chance to gel. The underfill may be injected until the entire substrate structure interface is substantially filled. Underfill material may also protect the C4 joints from moisture and other forms of contamination, and thus, it may be desirable to underfill beyond the boundaries of the bumped region so that the underfill “wicks up” the side of the die. Depending on the package needs, the amount of underfill injected beyond the bump region could be varied. After the appropriate amount of resin is injected it may be allowed to reach its desired state. Thermosets may be cured by exposing the package to a high temperature until the resin becomes sufficiently cross-linked. In one embodiment this curing could take place in-line by passing the package through a belt oven. Once the underfill 208 is set, it may act as a buffer between the first substrate structure 201 and the second substrate structure 204 and function to distribute the CTE-induced stress over the entire surface, during the cool down and subsequent thermal cycles throughout the chip life. FIG. 2 depicts an underfill process and IC package 300 in accordance with an embodiment of the present invention. In this embodiment the first substrate structure 201 may include a die and the second substrate structure 210 may include a package substrate, similar to the FIG. 1 embodiment. The IC package 300 may be prepared for die attach by cleaning the die pads 206, removing insulating oxides, and providing a pad metallurgy, including an ILD 209, that may protect the integrated circuit while making a good mechanical and electrical connection to the solder bumps 202. Solder bumps 202 may be formed on the first substrate structure 201 so that they are substantially aligned with the die pads 206. Solder bumps 202 may be formed by any number of methods, including, but not limited to, direct placement, electroplating, evaporation, jetting, printing, and stud bumping. The bumped die (201 and 202) may then be placed such that the solder bumps 202 are substantially aligned with the package pads 207. The bumped die may be placed using any number of standard die pick and place mechanisms, e.g., fine-pitch surface-mount technology or high-accuracy flip-chip placement equipment. In the embodiment depicted by FIG. 2, the first substrate structure 201 may be placed on the second substrate structure 210 by a precision head 301 that heats the first substrate structure 201 to approximately die-attach temperature. Applying heat to the die through the placement mechanism is optional, and may be absent in other embodiments. Once the solder bumps 202 are substantially aligned with both the die pads 206 and the package pads 207, the solder bumps 202 may be reflowed such that they wet both the pads. The solder may be raised to a reflow temperature by any combination of contact heat from second substrate structure 210, contact heat from the first substrate structure 201, ambient heat provided through a belt furnace, hot gas, or by some other local means. In an embodiment, the second substrate structure 210 may be heated by the injection mechanism 302 or by a substrate support (not shown). Generally, leaded solders have a lower reflow rate than lead-free solders, e.g., eutectic SnPb is around 183 degrees C., while SnAgCu or SnAg is around 230 degrees C. A lower reflow temperature may at least contribute to a reduction of residual stress from the cool down. However, other considerations, such as subsequent solder packaging, could require solder with higher reflow temperatures. When the solder reflows, the wetting forces of the solder may pull the bumps 202 and pads (206 and 207) into alignment. After reflowing, the IC package 300 may be allowed to cool below solidification temperature and an electrically and mechanically connective C4 joint may be formed between the first substrate structure 201 and the second substrate structure 210. Shortly following the joint formation, at a temperature slightly below the solidification temperature, an underfill material 208 may be injected into the interface area. In this embodiment the second substrate structure 210 may have a through hole 303 located approximately at the center of the die shadow. The through hole may have an unobstructed path from the second surface of the second substrate structure 210b to the first surface of the second substrate structure 210a to allow for underfill transmission. In other embodiments, design considerations could place the through hole off-center, or there may be several through holes located under the first substrate structure 201. In this embodiment, underfill 208 may be injected into the substrate structure interface from the second surface of the second substrate structure 210b using the injection mechanism 302. FIG. 3 graphically depicts the underfill timing for one embodiment of this invention as a function of process time and temperature. As the IC package is heated an optional flux may be applied 403 prior to joint formation 404 (hereinafter “joint formation” may also be referred to as “die-attach”) to ensure adequate wetting to the surfaces of the substrate structures, if so desired. After the solder has been heated past its melting point 405, the solder bumps may reflow into solder joints 404. Following the die-attach, the IC package is allowed to cool below the solder solidification temperature 406. Shortly after the IC package has dropped below solder solidification 406, underfill may be injected into the interface area 407. While the underfill may be injected prior to solder solidification, it may be advantageous to allow the solder to solidify in order to prevent first substrate structure movement upon the injection of the underfill. In one embodiment, the underfill may be injected prior to the package cooling down into the component cracking region 408. This practice may at least facilitate the support of the substrate structures and/or joints. The component cracking region 408 may be a temperature, range substantially at or below a component cracking temperature that may result in stress fractures in the ILD (or other parts of the substrate structures) and/or joints, in the absence of any additional support from the underfill. For example, in one embodiment an unsupported ILD may be vulnerable to cracking at temperatures around 180 degrees C. during the cool down; therefore the component cracking range would begin around 180 degrees C., even if the joints and the other substrate structure were not yet at risk at this temperature. In an embodiment, a triggering mechanism may be used to signal the injection of the underfill before the IC package drops into the component cracking region. This may be done by using temperature sensors, a timer coupled with known component cool down rates, or any other similar methods. Referring to FIG. 4, an optional integrated heat spreader (IHS) 501 may be placed over the first substrate structure 201 and attached to the second substrate structure 210 in order to dissipate and manage the heat produced during thermal cycles in the operation of the chip. The IHS 501 may be secured to the second substrate structure 210 by a sealant material 502. A thermal interface material (TIM) 503, such as a highly filled epoxy, may be added between the IHS 501 and the first substrate structure 201 to help transfer heat. The IHS 501 may also serve to define a cavity for the underfill 208 to be injected into, through a hole 303 in the second substrate structure 210. This cavity-defining feature could regulate the amount of underfill 208 to be applied. As discussed earlier, in some applications it may be beneficial to underfill beyond the substrate structure interface. Therefore, specifically tailoring the cavity to coincide with the desired amount and area of underfill 208 may prove beneficial. A cavity may also increase the flow-out rate by allowing a higher pressure injection to be used, without “blowing out” the underfill. In another embodiment, the underfill 208 could be injected into the cavity through a hole in the IHS 501. In various embodiments, the number and location of holes in the IHS 501 for injecting the underfill could be varied to accommodate design criteria. This embodiment could be employed as the sole point of injection with a standard package substrate (without a hole), or it could be used in conjunction with the second substrate structure 210 for injecting underfill from multiple locations. FIG. 5 shows another embodiment of this invention. In this embodiment, a first substrate structure 201 including a die is attached to a second substrate structure 204 including a package substrate, much the same way as discussed above with reference to earlier embodiments. In this embodiment, a chuck 601 may be placed over the first substrate structure 201 such that it provides a seal with the first surface of the second substrate structure 204a. The chuck 601 may be used to define a cavity surrounding the substrate structure interface. The cavity could define the area that the injected underfill 208 will consume. An optional gasket 603 may be located at the contact area between the chuck 601 and the first surface of the package substrate 204a. Optional downward pressure 602 from the chuck 601 may be applied to the topside of the first substrate structure 201. This pressure 602 may be utilized in various embodiments such as, but not limited to embodiments using thermocompression bonding techniques. It could also be advantageous in embodiments where the underfill injection takes place prior to solder joints annealing and forming a mechanical connection between the first substrate structure 201 and the second substrate structure 204. In those embodiments the downward pressure could help stabilize the first substrate structure 201 during the injection. The chuck 601 may also be used to heat and place the first substrate structure 201. After the package has cooled slightly from the die-attach temperatures, underfill 208 may be injected through a hole 604 in the chuck 601. In different embodiments, the position and number of the holes through which the underfill is injected may be varied depending on the specific needs of the manufacturing process. Embodiments of this invention may not only be beneficial by providing early support for the solder joints and package interface, but it may also present the possibility of using more diverse and potentially beneficial types and compositions of underfill. The CTE of the underfill material may at least in part compensate for a CTE mismatch between the die and the package substrate. In order to reduce the solder joint fatigue and to reinforce the ILD layer, the CTE of the underfill material may be in the range of about 20-40 ppm/deg C. Raw epoxy resin, which may be used as the base material for the underfill, has a CTE of approximately 70 ppm/deg C. This may be too high for many underfill applications where typical CTEs for silicon, solder, and substrates are between 4 ppm/deg C and 21 ppm/deg C. In order to lower the CTE, filler particles like silica, for example, may be added. However, as filler particles are added the viscosity of the underfill rises, which may make it more difficult to flow out. With the injection force used in embodiments of this invention potentially being more substantial than the capillary force, it may be possible to work with higher viscosity/lower CTE underfill materials. In an embodiment, a thermoplastic resin may be used as the underfill material. As discussed earlier, the curing of a thermosetting resin involves a cross-linking of polymer chains. Once this structural change occurs, it may be difficult to reverse. However, often testing of the packaged part results in the need for reworking the component parts, which may be difficult with thermosetting material. Contrary to thermosets, when thermoplastics are heated and injected into interface, there is no structural change of the molecules. So even after the plastic has cooled and hardened into shape, it may be subsequently reheated and reworked as necessary. Thermoplastics are also known as “reworkable underfills.” Referring to FIG. 6, there is illustrated one of many possible systems in which embodiments of the present invention may be used. The IC package 625 may be similar to the IC packages depicted in above FIGS. 1, 2, 4, and 5. In one embodiment, the IC package 625 may include a microprocessor 630. In an alternate embodiment, the IC package 625 may include an application specific IC (ASIC). Integrated circuits found in chipsets, e.g., graphics (similar to the graphics processor 635), sound and control chipsets, may also be packaged in accordance with embodiments of this invention. For the embodiment depicted by FIG. 6, the system 620 also includes a main memory 640, a graphics processor 635, a mass storage device 645, and an input/output module 650 coupled to each other by way of a bus 655, as shown. Examples of the memory 640 include but are not limited to static random access memory (SRAM) and dynamic random access memory (DRAM). Examples of the mass storage device 645 include but are not limited to a hard disk drive, a compact disk drive (CD), a digital versatile disk drive (DVD), and so forth. Examples of the input/output modules 650 include but are not limited to a keyboard, cursor control devices, a display, a network interface, and so forth. Examples of the bus 655 include but are not limited to a peripheral control interface (PCI) bus, and Industry Standard Architecture (ISA) bus, and so forth. In various embodiments, system 620 may be a wireless mobile phone, a personal digital assistant, a pocket PC, a tablet PC, a notebook PC, a desktop computer, a set-top box, an audio/video controller, a DVD player, and a server. Conclusion and Epilogue Thus, it can be seen from the above descriptions, a novel underfilled IC package has been described. Although specific embodiments have been illustrated and described herein for purposes of description of the preferred embodiment, it will be appreciated by those of ordinary skill in the art that a wide variety of alternate and/or equivalent implementations calculated to achieve the same purposes may be substituted for the above embodiments without departing from the scope of the present invention. Those with skill in the art will readily appreciate that the present invention may be implemented in a wide variety of embodiments. This application is intended to cover any adaptations or variations of the embodiments discussed herein. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof. | <SOH> FIELD OF THE INVENTION <EOH>The present invention relates to the field of integrated circuits, and more particularly, to an integrated circuit package adapted to receive underfill injected at near die-attach temperatures, and a process to make the same. | <SOH> BRIEF DESCRIPTION OF DRAWINGS <EOH>FIG. 1 is a cross-sectional view of an IC package, in accordance with one embodiment of this invention; FIG. 2 is a cross-sectional view of an underfill process, in accordance with an embodiment of this invention; FIG. 3 is a graphical representation of process cycles as a function of time and temperature, in accordance with an embodiment of this invention; FIG. 4 is a cross-sectional view of an IC package with an integrated heat spreader, in accordance with an embodiment of this invention; FIG. 5 is a cross-sectional view of an IC package underfill process, in accordance with an embodiment of this invention; and FIG. 6 is a block diagram of a system including an IC package, in accordance with one embodiment of this invention. detailed-description description="Detailed Description" end="lead"? | 20040106 | 20051227 | 20050707 | 69687.0 | 0 | GEYER, SCOTT B | APPARATUS AND METHODS FOR AN UNDERFILLED INTEGRATED CIRCUIT PACKAGE | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,755,396 | ACCEPTED | Wear-premonitory carbon brush holder | A wear-premonitory carbon brush holder includes a holder body and a premonitory circuit. A carbon brush that is received in the holder body is reciprocately moveable in the holder body along a predetermined path. The premonitory circuit has a sensing unit mounted on the holder body for activating the premonitory circuit to generate a predetermined action or a warning signal when the carbon brush moves in the holder body to a predetermined position. | 1. A wear-premonitory carbon brush holder comprising; a holder body for receiving therein a carbon brush, which is reciprocately moveable in the holder body along a predetermined path, and a premonitory circuit having a sensing unit mounted on said holder body for activating said premonitory circuit to generate a predetermined action or a warning signal when the carbon brush moves in the holder body to a predetermined position. 2. The carbon brush holder as defined in claim 1, wherein said holder body comprises a receiving slot for receiving therein said carbon brush and a spring connected between said holder body and said carbon brush; said sensing unit comprises a tongue that is mounted on said holder body and has an end extending into said receiving slot to a position where said spring can touch when said spring extends, thereby activating said premonitory circuit to generate the predetermined action or the warning signal when said spring touches said tongue. 3. The carbon brush as defined in claim 2, wherein said holder body further comprises a copper barrel in which the receiving slot is provided, said copper barrel having a through hole running therethrough between said receiving slot and an outside thereof; said sensing unit further comprises an insulated plug inserted into said through hole of said copper barrel; wherein said tongue is mounted through said insulated plug. 4. The carbon brush as defined in claim 2, wherein said premonitory circuit comprises an alarm indicator for generating the warning signal when said tongue contacts said spring. 5. The carbon brush as defined in claim 2, wherein said premonitory circuit comprises a normally open switch loop and a warning unit, said switch loop being electrically conducted while said tongue contacts said spring to enable said warning unit to generate the warning signal. 6. The carbon brush as defined in claim 1, wherein said holder body comprises a receiving slot for receiving therein said carbon brush and a spring connected between said holder body and said carbon brush; said sensing unit comprises a first tongue and a second tongue, said first and second tongues being mounted on said holder body and spaced apart from each other for a distance, each of said two tongues having an end extending into said receiving slot, said spring contacting against one of said ends of the tongues when said spring extends to enable said tongue that has said end contacted by said spring to bend to contact the other tongue, further activating said premonitory circuit to generate the action or the warning signal. 7. The carbon brush holder as defined in claim 6, wherein said holder body further comprises a copper barrel in which said receiving slot is provided, said copper barrel having a through hole running therethrough between said receiving slot and an outside thereof; said sensing unit further comprises an insulated plug inserted into said through hole of said copper barrel; wherein said first and second tongues are mounted through said insulated plug. 8. The carbon brush holder as defined in claim 6, wherein said premonitory circuit comprises a normally open switch loop and a warning unit, said switch loop being electrically conducted while said spring contacts said respective tongue to enable said warning unit to generate the warning signal. 9. The carbon brush as defined in claim 1, wherein said holder body comprises a receiving slot for receiving therein said carbon brush and a spring; said sensing unit comprises a first tongue and a second tongue, said first and second tongues being mounted on said holder body and spaced apart from each other for a distance, each of said two tongues having an end extending into said receiving slot, said two ends contacting each other, the length that one of said two tongues extends into said receiving slot being larger than the other tongue, one of said tongues being disposed in a position where said respective tongue is contacted by said spring when said spring extends such that said respective tongue that is contacted by said spring is bent to disengage from the other tongue, further activating said premonitory circuit to generate the action or the warning signal. 10. The carbon brush as defined in claim 9, wherein said holder body further comprises a copper barrel in which said receiving slot is provided, said copper barrel having a through hole running therethrough between said receiving slot and an outside thereof; said sensing unit further comprises an insulated plug inserted into said through hole of said copper barrel; wherein said first and second tongues are mounted through said insulated plug. 11. The carbon brush as defined in claim 9, wherein said premonitory circuit comprises a normally close switch loop and a warning unit, said switch loop being off to activate said warning unit to generate the warning signal while said spring contacts said respective tongue. 12. The carbon brush holder as defined in claim 1, wherein said holder body comprises a receiving slot for receiving therein said carbon brush and a spring connected between said holder body and said carbon brush; said sensing unit comprises a tongue mounted on said holder body and having an end extending into said receiving slot to keep contacting said carbon brush; when said carbon brush disengages from said tongue, said premonitory circuit is activated to generate the action or the warning signal. 13. The carbon brush holder as defined in claim 12, wherein said holder body further comprises a copper barrel in which said receiving slot is provided, said copper barrel having a through hole running therethrough between said receiving slot and an outside thereof; said sensing unit further comprises an insulated plug inserted into said through hole of said copper barrel; wherein said tongue is mounted through said insulated plug. 14. The carbon brush as defined in claim 12, wherein said premonitory circuit comprises a normally close switch loop and a warning unit, said switch loop being off to generate the warning signal while said tongue disengages from said carbon brush. 15. The carbon brush as defined in claim 1, wherein said holder body comprises a receiving slot for receiving therein said carbon brush and a spring connected between said holder body and said carbon brush; said sensing unit is a resilient switch composed of a shell, a spring, and an actuating bar, each of said shell and said actuating bar having a conductive piece; when said actuating bar is exerted by none of any force, said spring keeps pushing against said actuating bar to enable said two conductive pieces to contact each other; when said actuating bar is exerted by a force, said actuating bar moves towards inside of said shell to compress said spring to enable said two conductive pieces to disengage from each other, said resilient switch being mounted on said holder body, said actuating bar keeping oppressed by said carbon brush to move towards inside of said shell; when said carbon brush disengages from said actuating bar, said two conductive pieces contact each other to activate said premonitory circuit to generate the action or the warning signal. 16. The carbon brush as defined in claim 15, wherein said premonitory circuit comprises a normally open switch loop and a warning unit, said switch loop being electrically conducted to activate said warning unit to generate the warning signal while said two conductive pieces of said resilient switch contact each other. 17. The carbon brush as defined in claim 1, wherein said sensing unit is composed of an infrared transmitter and an infrared receiver, said infrared transmitter and receiver being mounted at two opposite sides of said holder body, said carbon brush interrupting the communication between said infrared transmitter and receiver; when said carbon brush moves away to remove the interruption of the communication, said premonitory circuit is activated to generate the action or the warning signal. | BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to carbon brushes for use in motors, and more particularly to a wear-premonitory carbon brush holder. 2. Description of the Related Art As shown in FIG. 1, a conventional carbon brush holder 1 includes a holder body 11 for accommodating a spring A and a carbon brush B. The spring A has an end contacting against an internal end of the holder body 11 and the other end contacting against an end of the carbon brush B; meanwhile, the carbon brush B is pushed by the spring A to contact against the rotor C of the motor and then transfers the electric current to the rotor C to drive the rotor C to rotate. Because the friction generated between the carbon brush B and the rotor C wears the carbon brush B, the carbon brush B needs the resilience generated by the spring A to keep contacting against the rotor C. However, the resilience of the spring A will be gradually reduced when the spring A is self-extended along with the wear of the carbon brush B. When the carbon brush B is worn to a certain degree, the spring A fails to provide sufficient resilience to enable the carbon brush B to keep contacting against the rotor C, such that a gap will be formed between the carbon brush B and the rotor C to incur imperfect contact therebetween to further generate arc sparks. Thus, when the motor mounted with the carbon brush holder 1 is operated, the operator has to frequently check the wear degree of the carbon brush B and replace the carbon brush B when the carbon brush B is worn to a certain degree. As shown in FIG. 2, another conventional carbon brush holder 2 is different from the aforementioned carbon brush holder 1 by that the spring D is a constant-force spring that generates balanced constant resilience to avoid the generation of the aforementioned arc sparks; however, the operator still has to frequently check the wear degree of the carbon brush 2. SUMMARY OF THE INVENTION The primary objective of the present invention is to provide a carbon brush holder that premonishes the operator to replace the carbon brush when the carbon brush is worn to a certain degree, and thereby it is unnecessary to frequently check whether the carbon brush is worn out and needs to be replaced. The foregoing objective of the present invention is attained by the wear-premonitory carbon brush holder that is composed of a holder body and a premonitory circuit. A carbon brush is received in the holder body and slidably reciprocates along a predetermined path. The premonitory circuit has a sensing unit mounted on the holder body for activating the premonitory circuit to generate a predetermined action or a warning signal when the carbon brush moves to a predetermined position. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a conventional carbon brush working with a rotor of a motor; FIG. 2 is a schematic view of another conventional carbon brush working with a rotor of a motor; FIG. 3 is a sectional view of a first preferred embodiment of the present invention, showing that a tongue is away from a spring; FIG. 4 is another sectional view of the first preferred embodiment of the present invention, showing that the tongue contacts the spring; FIG. 5 is a sectional view of a second preferred embodiment of the present invention; FIG. 6 is a sectional view of a third preferred embodiment of the present invention; FIG. 7 is a sectional view of a fourth preferred embodiment of the present invention; FIG. 8 is a top view of a fifth preferred embodiment of the present invention; FIG. 9 is a sectional view of the fifth preferred embodiment of the present invention, showing that a carbon brush contacts the tongue; FIG. 10 similar to FIG. 9 shows that the tongue is away from the carbon brush; FIG. 11 is a front sectional view of a sixth preferred embodiment of the present invention; FIG. 12 is a right sectional view of the sixth preferred embodiment of the present invention, showing that an actuating bar is oppressed; FIG. 13 is another right sectional view of the sixth preferred embodiment of the present invention, showing that the actuating bar is not exerted by a force; and FIG. 14 is a sectional view of a seventh preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 3, a carbon brush holder 3 constructed according to a first preferred embodiment of the present invention is composed of a holder body 20 and a premonitory circuit 30. The holder body 20 includes a base 21 and a copper barrel 22 in which an elongated receiving slot 23 that has an opening is provided. A spring A and a carbon brush B are accommodated in the receiving slot 23 through the opening. The holder body 20 has a through hole 24 running through the inner and outer walls of the copper barrel 22. The premonitory circuit 30 includes a sensing unit 31 and an alarm indicator 32, which is embodied as a warning lamp in this preferred embodiment. The sensing unit 31 is formed of an insulated plug 33 and an electrically conductive member which is embodied as a copper springy tongue 34 in this embodiment. The insulated plug 33 is securely disposed in the through hole 24 of the copper barrel 22. The springy tongue 34 is inserted into a midsection of the insulated plug 33 and has a free end extending into the receiving slot 23 and the other end electrically connected with the alarm indicator 32 of the premonitory circuit 30 by wire. When the carbon brush B is worn to a certain degree, the spring A that is self-extended due to the wear of the carbon brush B contacts the free end of the springy tongue 34 as shown in FIG. 4. Referring to FIG. 4, when an end of the carbon brush B keeps contacting against a surface of a rotor E of a motor to be worn, the spring A resiliently extends forwards to keep the worn end of the carbon brush B contacting against the surface of the rotor E. When the spring A resiliently extends further for a length to contact the springy tongue 34, the electric current flows through the connection between the spring A and the springy tongue 34 to electrically conduct the premonitory circuit 30 to further activate the alarm indicator 32 to function. When the carbon brush B is worn for a predetermined length, the premonitory circuit 30 generates a predetermined action or transmits a warning signal to prompt the operator to replace the worn carbon brush B, such that the operator will not have to frequently check the wear degree of the carbon brush B and decide whether the carbon brush B needs to be replaced. Hence, the present invention saves lots of time of checking for the operator to avoid the carbon brush B from being worn-out that causes sudden stop of the motor to further incur abnormal operation. The sensing unit of the premonitory circuit and the warning signal can be any alternatives that alert the operator to replace the carbon brush when the carbon brush is worn to a certain degree. Referring to FIG. 5, the carbon holder 4 constructed according to a second preferred embodiment of the present invention is shown different from the aforementioned first preferred embodiment by that the premonitory circuit 30 further includes a normally open switch loop 35 and a warning unit (not shown), which can be embodied as a buzzer, an alarm indicator, and so on, in addition to the sensing unit 31. When the carbon brush B is worn to a certain degree, the spring A extends to contact the springy tongue 34 to be electrically connected with the switch loop 35 to further activate the warning unit to function. Referring to FIG. 6, the carbon holder 5 constructed according to a third preferred embodiment of the present invention is different from the second preferred embodiment by that the premonitory circuit 40 further includes a sensing unit 41 having an insulated plug 43, a first tongue 44 and a second tongue 45 in addition to the normally open switch loop 42 and the warning unit (not shown). The first and second tongues 44 and 45 are inserted inside the insulated plug 43 and parallel spaced apart from each other for a predetermined distance. The first and second tongues 44 and 45 each have a free end extending into the receiving slot 23 of the holder body 20 to be at a position which the spring A can contact while the spring A extends, and other end connected with the premonitory circuit 40. Thus, the two tongues 44 and 45 contact each other to electrically conduct the switch loop 42 to activate the warning unit to function. When the carbon brush B is worn to enable the spring A to extend to a predetermined position, the spring A contacts and pushes the first tongue 44 to bend, then the first tongue 44 contacts the second tongue 45 to enable the switch loop 42 of the premonitory circuit 40 to be electrically conducted, and further the warning unit transmits a warning signal or action. Referring to FIG. 7, the carbon holder 6 constructed according to a fourth preferred embodiment of the present invention is characterized in that the premonitory circuit 50 includes a sensing unit 51 having a first tongue 53 and a second tongue 54 and an insulated plug 55, a normally close switch loop 52 and a warning unit (not shown). The free ends of the first and second tongues 53 and 54 are slightly set to contact each other without bearing a force. In addition, the first tongue 53 is positioned close to the opening of the holder body 20 more than the second tongue 54 does, and the length that the first tongue 53 extends into the receiving slot 23 is longer than the second tongue 54. When the carbon brush B is worn to enable the spring A to extend for a predetermined length, the first tongue 53 is contacted by the spring A to be pushed to further disengage from the second tongue 54, such that the switch loop 52 is off to activate the warning unit to transmit a warning signal. Referring to FIGS. 8-10, the carbon brush holder 7 constructed according to a fifth preferred embodiment of the present invention is characterized in that the premonitory circuit 60 includes a sensing unit 61 having a tongue 63 and an insulated plug 64, a normally close switch loop 62 and a warning unit (not shown). The tongue 63 is inserted inside the insulated plug 64 that is mounted on the holder body 20 and has a free end extending to the receiving slot 23 to keep contacting the carbon brush B. When the tongue 63 disengages from the carbon brush B, the normally close switch loop 62 is off to activate the warning unit. Referring to FIGS. 11-13, the carbon brush holder 8 constructed according to a sixth preferred embodiment of the present invention is composed of a holder body 70 and a premonitory circuit 80. The holder body 70 includes a receiving slot 71 and a through hole 72. The receiving slot 71 has an opening at a top end thereof for accommodating a constant-force spring D and a carbon brush B. The through hole 72 is positioned on the holder body 70 away from the opening of the receiving slot 71 and runs through the holder body for communication between inside and outside of the holder body 70. The premonitory circuit 80 includes a resilient switch 81, a normally open switch loop (not shown), and a warning unit (not shown). The resilient switch 81 is composed of a shell 83, a spring 84, and an actuating bar 85. Each of the shell 83 and the actuating bar 85 is provided with a conductive piece 86. When the actuating bar 85 is not exerted by any of forces, the spring 84 pushes the actuating bar 85 to enable the two conductive pieces 86 to contact each other. When the actuating bar 85 is exerted by a force, the actuating bar 85 is driven to moves towards inside of the shell 83 to compress the spring 84 to isolate the two conductive pieces 86, as shown in FIG. 12. The resilient switch 81 is mounted inside the through hole 72 of the holder body 70. Normally, the actuating bar 85 is pushed by the carbon brush B at an end thereof to move towards inside the shell 93 to compress the spring 84, as sown in FIG. 12. The switch loop is designed being electrically conducted by the contact of the two conductive pieces 87 to further activate the warning unit. When the carbon brush B is worn to be pushed outwards by the constant-force spring D to disengage from the actuating bar 85, the spring 84 pushes the actuating bar 85 to move towards the carbon brush B to enable the conductive piece 86 of the actuating bar 85 to contact the conductive piece 86 of the shell 83, as shown in FIG. 13, and the switch loop is electrically conducted to activate the warning unit to transmit a warning signal. Referring to FIG. 14, the carbon brush holder 9 constructed according to a seventh preferred embodiment of the present invention is different from the aforementioned preferred embodiments by that the sensing unit 90 is composed of an infrared transmitter and an infrared receiver. The carbon brush B interrupts the communication between the infrared transmitter and the infrared receiver in a normal condition. When the carbon brush B is worn for a predetermined length, the carbon brush B moves away to remove the interruption of the communication and then the receiver can receive the signal transmitted from the transmitter, thereby activating the premonitory circuit 92 to transmit the warning signal. Furthermore, the sensing unit of the present invention can alternatively be other sensors, such as a sensor that detects the difference of colors or materials. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates generally to carbon brushes for use in motors, and more particularly to a wear-premonitory carbon brush holder. 2. Description of the Related Art As shown in FIG. 1 , a conventional carbon brush holder 1 includes a holder body 11 for accommodating a spring A and a carbon brush B. The spring A has an end contacting against an internal end of the holder body 11 and the other end contacting against an end of the carbon brush B; meanwhile, the carbon brush B is pushed by the spring A to contact against the rotor C of the motor and then transfers the electric current to the rotor C to drive the rotor C to rotate. Because the friction generated between the carbon brush B and the rotor C wears the carbon brush B, the carbon brush B needs the resilience generated by the spring A to keep contacting against the rotor C. However, the resilience of the spring A will be gradually reduced when the spring A is self-extended along with the wear of the carbon brush B. When the carbon brush B is worn to a certain degree, the spring A fails to provide sufficient resilience to enable the carbon brush B to keep contacting against the rotor C, such that a gap will be formed between the carbon brush B and the rotor C to incur imperfect contact therebetween to further generate arc sparks. Thus, when the motor mounted with the carbon brush holder 1 is operated, the operator has to frequently check the wear degree of the carbon brush B and replace the carbon brush B when the carbon brush B is worn to a certain degree. As shown in FIG. 2 , another conventional carbon brush holder 2 is different from the aforementioned carbon brush holder 1 by that the spring D is a constant-force spring that generates balanced constant resilience to avoid the generation of the aforementioned arc sparks; however, the operator still has to frequently check the wear degree of the carbon brush 2 . | <SOH> SUMMARY OF THE INVENTION <EOH>The primary objective of the present invention is to provide a carbon brush holder that premonishes the operator to replace the carbon brush when the carbon brush is worn to a certain degree, and thereby it is unnecessary to frequently check whether the carbon brush is worn out and needs to be replaced. The foregoing objective of the present invention is attained by the wear-premonitory carbon brush holder that is composed of a holder body and a premonitory circuit. A carbon brush is received in the holder body and slidably reciprocates along a predetermined path. The premonitory circuit has a sensing unit mounted on the holder body for activating the premonitory circuit to generate a predetermined action or a warning signal when the carbon brush moves to a predetermined position. | 20040113 | 20060516 | 20050526 | 94321.0 | 1 | LE, DANG D | WEAR-PREMONITORY CARBON BRUSH HOLDER | SMALL | 0 | ACCEPTED | 2,004 |
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10,755,419 | ACCEPTED | In2O3 thin film resistivity control by doping metal oxide insulator for MFMox device applications | The present invention discloses a novel ferroelectric transistor design using a resistive oxide film in place of the gate dielectric. By replacing the gate dielectric with a resistive oxide film, and by optimizing the value of the film resistance, the bottom gate of the ferroelectric layer is electrically connected to the silicon substrate, eliminating the trapped charge effect and resulting in the improvement of the memory retention characteristics. The resistive oxide film is preferably a doped conductive oxide in which a conductive oxide is doped with an impurity species. The doped conductive oxide is most preferred to be In2O3 with the dopant species being hafnium oxide, zirconium oxide, lanthanum oxide, or aluminum oxide. | 1-10. (canceled) 11. A method of fabricating a ferroelectric transistor comprising the steps of: preparing a semiconductor substrate; forming a gate stack on the substrate, the gate stack comprising a conductive oxide overlying the substrate; doping the conductive oxide using an impurity species: modifying the resistance of the conductive oxide in response to the impurity species, forming a doped conductive oxide; and forming drain and source regions on opposite sides of the gate stack. 12. A method as in claim 11 wherein the I-V characteristic of the doped conductive oxide is substantially linear. 13. A method as in claim 11 wherein the gate stack farther comprises a ferroelectric material layer over the doped conductive oxide layer; and a top electrode conductive layer over the ferroelectric material layer. 14. A method as in claim 11 wherein the gate stack further comprises a bottom electrode conductive layer over the doped conductive oxide layer; a ferroelectric material layer over the bottom electrode layer; and a top electrode conductive layer over the ferroelectric material layer. 15. A method as in claim 13 wherein the top electrode conductive layer is selected from the group including a layer of metal, a layer of conductive, oxide or a multilayer of metal and conductive oxide. 16. A method as in claim 11 wherein the doped conductive oxide layer comprises a conductive perovskite oxide, a high temperature superconducting oxide, or an oxide film of any metal selected from a group consisted of Mo, W, Tc, Re, Ru, Os, Rh, Ir, Pd, Pt, In, Zn, Sn, Nd, Nb, Sm, La, and V. 17. A method as in claim 11 wherein the conductive oxide is indium oxide. 18. A method as in claim 11 wherein the impurity species is selected from a groups consisting of Hf, Zr, Al, La, hafnium oxide, zirconium oxide, aluminum oxide and lanthanum oxide. 19. A method as in claim 11 wherein the doped conductive oxide is indium oxide doped with hafnium oxide, zirconium oxide, lanthanum oxide or aluminum oxide. 20. A method as in claim 11 wherein the gate stack is a replacement gate stack further comprising a sacrificial layer over the doped conductive oxide layer, and the fabrication method further comprising the following steps filling the areas surrounding the replacement gate stack while exposing the top portion of the replacement gate stack; removing the sacrificial layer portion of the replacement gate stack; forming the remainder of the gate stack, the remainder of the gate stack comprising a ferroelectric material layer over the conductive oxide layer; and a top electrode conductive layer over the ferroelectric material layer. 21. A method as in claim 20 wherein the replacement gate stack further comprises a bottom electrode conductive layer positioned between the conductive oxide layer and the sacrificial layer. 22. A method as in claim 20 wherein the filling of the areas surrounding the replacement gate stack while exposing a top portion of the replacement gate stack comprises the deposition of a dielectric film; and the planarization of the deposited dielectric film to expose the top portion of the replacement gate stack. 23. A method as in claim 20 wherein the formation of the remainder of the gate stack comprises the deposition of the ferroelectric material layer; the planarization of the ferroelectric material layer; the deposition of the top electrode conductive layer; the photolithography patterning of the top electrode conductive layer; and the etching of the top electrode conductive layer. 24. A method of fabricating a ferroelectric transistor comprising: supplying a semiconductor substrate; forming an indium oxide layer overlying the substrate; doping the indium oxide with an impurity species; modifying the resistance of the indium oxide, forming a doped indium oxide layer; forming a ferroelectric material layer overlying the doped indium oxide layer; forming a gate top electrode conductive layer overlying the ferroelectric material layer; and forming drain and source regions. 25. The method of claim 24 further comprising: forming a bottom electrode interposed between the doped indium oxide layer and the ferroelectric material layer. 26. A method of fabricating a ferroelectric transistor comprising: supplying a silicon (Si) substrate; forming a metal oxide layer overlying the substrate; doping the metal oxide layer with an impurity species; in response to the doping, forming a conductive metal oxide layer; forming a gate stack overlying the conductive oxide layer; forming source and drain regions; in response to forming the conductive oxide layer, preventing elements from diffusing into the Si substrate from the gate stack; and in response to forming the conductive oxide layer, forming an electrically conductive path between the gate stack and the Si substrate. 27. The method of claim 28 wherein forming the gate stack includes: forming a ferroelectric material layer overlying the conductive oxide layer; forming a gate top electrode conductive layer overlying the ferroelectric material layer. 28. The method of claim 27 wherein forming the gate stack further includes: forming a bottom electrode interposed between the conductive oxide layer and the ferroelectric material layer. | FIELD OF THE INVENTION This invention relates generally to semiconductor device and nonvolatile memory transistor, and more particularly to ferroelectric gate transistor structures and methods of fabrication. BACKGROUND OF THE INVENTION Ferroelectric materials are composed of many randomly-distributed permanently polarized regions. Under the presence of an electric field, the regions with a polarization component in the direction of the electric field grow at the expense of the non-aligned regions so that a net polarization can result. If the electric field decreases, the polarization also decreases but at a slower rate so that even when the electric field becomes zero, a remnant polarization remains. A negative coercive field is required to bring the polarization to zero. This hysteresis behavior of a ferroelectric material is the basis of ferroelectric nonvolatile memory devices. Currently there are two types of ferroelectric nonvolatile memory devices: ferroelectric capacitor which uses a transistor to detect the polarization of a ferroelectric capacitor, and ferroelectric transistor which detects a change in the transistor conductance caused by the polarization of a ferroelectric gate material. The ferroelectric transistor is much more advantageous than the ferroelectric capacitor due to the smaller surface area which enables higher density memory chip, and the non-destructive readout which significantly reduces the fatigue problem. The ferroelectric transistor is typically a ferroelectric-gate-controlled semiconductor field-effect transistor (FET), which employs a ferroelectric film in the gate stack of the FET, and in which a proper polarization of the ferroelectric film can create an inversion layer in the channel region of the transistor. The basic ferroelectric-gate controlled field-effect transistor is a metal-ferroelectric silicon (MFS) FET. The term MFS represents the layers in the gate stack of the ferroelectric transistor. Thus the gate stack of the MFS transistor consists of a metal (M) gate electrode disposed on a ferroelectric (F) gate dielectric on the silicon (S) channel of the transistor. FIG. 1 shows the schematic of an n-channel MFS transistor. A ferroelectric film 12 is formed as a gate insulating film on a p-type silicon substrate 13, together with source 14 and drain 15 regions having a high concentration of n-type impurity ions. A metal gate electrode 11 is formed over the ferroelectric film 12. The MFS transistor is isolated by the isolation trenches 16. However, effective transistor operation of the above MFS transistor is difficult to achieve due to the requirement of the ferroelectric/silicon interface. When a ferroelectric film is deposited directly on the silicon substrate, metals and oxygen from the ferroelectric layer may diffuse into the ferroelectric-silicon interface, creating interface trapped charges which affect the polarization of the ferroelectric film, and overall may make the operation of the ferroelectric transistor unstable. Further, since the thermal expansion coefficient and lattice structure of a ferroelectric film is not compatible with silicon, it is very difficult to form a high-quality ferroelectric film with a clean interface directly on the silicon substrate. To address the drawbacks posed by the direct ferroelectric/silicon interface, a gate dielectric can be inserted between the ferroelectric film and the silicon substrate. The ferroelectric transistor is then called metal-ferroelectric-oxide (or insulator) silicon (MFOS or MFIS) FET. FIG. 2A shows a MFOS memory transistor using a gate oxide layer 27 formed between the silicon substrate 13 and the ferroelectric film 12. Alternatively, a metal floating gate layer 28 can be added between the ferroelectric film 12 and the gate oxide layer 27 as shown in FIG. 2B for a metal-ferroelectric-metal-oxide (or insulator) silicon (MFMOS or MFMIS) transistor. A suitable conducting material (e.g. Pt or Ir) is normally selected for the floating gate 28 to allow the deposition of the ferroelectric thin film and to prevent diffusion of the ferroelectric material into the gate dielectric and the channel. The floating gate layer 28 is also called bottom electrode, or bottom gate, in reference to the other gate electrode 11, called top electrode, or top gate. Such gate stack structures (metal-ferroelectric-oxide gate stack or metal-ferroelectric-metal-oxide gate stack) overcome the surface interface and surface state issues of a ferroelectric layer in contact with the silicon substrate. However, they incorporate other difficulties such as higher operation voltage and trapped charges in the bottom floating gate layer. The operation voltage of these transistors is higher than the ferroelectric layer programming voltage by an amount of the voltage across the gate dielectric. And when there is a voltage applied across the ferroelectric thin film, there will be current flow in the gate stack, and charges would be trapped in this floating electrode. The trapped charges may neutralize the polarization charges at the interface of the bottom electrode and the ferroelectric film and could shorten the memory retention time of this structure. Various prior designs have been disclosed to compensate for the trapped charges in the floating bottom electrode. One of the prior art design to reduce the trapped charges in the lower electrode is the formation of a Schottky diode such as a metal-ferroelectric-metal silicon (MFMS) device disclosed in Nakao et al., U.S. Pat. No. 5,303,182, entitled “Nonvolatile semiconductor memory utilizing a ferroelectric film”. A Schottky barrier is formed between the bottom metal electrode of the gate unit (or a very shallow junction layer) and the silicon substrate. The Schottky ferroelectric gate memory transistor requires a space between the bottom electrode and the source and drain region or a very shallow n-channel under the gate, therefore the drive current of the Schottky ferroelectric gate memory transistor can be relatively low. Hsu et al., U.S. Pat. No. 5,731,608, entittled “One transistor ferroelectric memory cell and method of making the same”, and its continuations and divisions (U.S. Pat. Nos. 5,962,884; 6,117,691; 6,018,171; 5,942,776; 5,932,904; 6,146,904; 6,011,285; 6,531,325), hereby incorporated by reference, disclose a distance between 50 to 300 nm from the bottom metal electrode to the source and drain to reduce the possible high leakage current due to the increased field intensity at the metal edge of the Schottky diode because of the sharp edge at the periphery of the metal contact. Alternatively, Willer et al., U.S. Pat. No. 6,538,273, entittled “Ferroelectric transistor and method for fabricating it”, discloses a recess of the source and drain below the surface of the semiconductor surface in a Schottky ferroelectric gate memory transistor. Another design to reduce the trapped charges in the lower electrode is to provide a conduction path for the lower electrode. Black et al., U.S. Pat. No. 6,069,381, entitled “Ferroelectric memory transistor with resistively coupled floating gate” discloses an integrated resistor in the form of a spacer between the bottom floating gate electrode and the source/drain to remove the trapped charges. Moise et al., U.S. Pat. No. 6,225,655 and its continuation U.S. Pat. No. 6,362,499, entitled “Ferroelectric transistors using thin film semiconductor gate electrodes” disclose an external resistor connecting the lower electrode to ground to drain the trapped charges. This additional resistor ensures that the potential of the floating gate will approach that of the source/drain region after a certain delay time, but this could affect the high speed switching characteristic of the ferroelectric memory. Yoo, U.S. Pat. No. 5,812,442, entitled “Ferroelectric memory using leakage current and multi-numerical system ferroelectric memory” discloses a leakage gate dielectric to remove the trapped charges through the silicon channel. The leakage current is generated by a Schottky emission or a Frankel-Poole emission or Fowler-Nordheim tunneling to reduce the bound charges in the bottom metal electrode. SUMMARY OF THE INVENTION The present invention discloses a novel design to reduce the trapped charges in the ferroelectric transistor operation by the use of a resistive oxide film in place of the gate dielectric, fabricated with proper resistance value to optimize the performance of the ferroelectric transistor. By replacing the gate dielectric with a resistive oxide film, and by optimizing the value of the film resistance, the bottom gate of the ferroelectric layer is electrically connected to the silicon substrate, therefore the floating gate effect can be eliminated, resulting in the improvement of the memory retention characteristics. Furthermore, the operating voltage for the ferroelectric transistor can be reduced because of the absence of the gate dielectric The resistive oxide film is preferably a doped conductive oxide which is a conductive oxide doped with an impurity species. By varying the dopant concentration and other fabrication process parameters, the resistive oxide film can achieve a wide range of resistance suitable for the optimization of the ferroelectric transistor performance. The doped conductive oxide is most preferred to be In2O3 with the dopant species being hafnium oxide, zirconium oxide, lanthanum oxide, or aluminum oxide. The present invention ferroelectric transistor can be a metal-ferroelectric-metal-doped conductive oxide silicon (MFMRS) FET. The gate stack of the MFMRS transistor has a top metal electrode (or top gate) disposed on a ferroelectric layer disposed on a bottom metal electrode (or bottom gate) disposed on a doped conductive oxide layer on the silicon substrate. The present invention ferroelectric transistor can also be a metal-ferroelectric-doped conductive oxide silicon (MFRS) FET. The gate stack of the MFRS transistor has a top metal electrode (or top gate) disposed on a ferroelectric layer disposed on a doped conductive oxide layer on the silicon substrate. The resistive doped conductive oxide further can have the advantages of possible lattice matching with the ferroelectric layer, reducing or eliminating the oxygen diffusion problem at the ferroelectric interface to improve the reliability of the ferroelectric transistor, and possible etch selectivity improvement with other dielectric and metal films. The fabrication process of the present invention ferroelectric transistor can be performed by a gate etching process or by a replacement gate process. In the gate etching process, the multilayer gate stack is deposited and etched, while in the replacement gate process, a replacement gate stack is deposited as a place holder for the fabrication of other portions of the device, then the replacement gate stack is removed and the functional gate stack is deposited. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a typical ferroelectric-gate-controlled semiconductor field-effect transistor (FET) which is a metal-ferroelectric silicon (MFS) FET. FIG. 2A shows a schematic of a metal-ferroelectric-oxide silicon MFOS transistor. FIG. 2B shows a schematic of a metal-ferroelectric-metal-oxide silicon MFMOS transistor. FIG. 3 shows the X-ray patterns of doped In2O3 thin films with various hafnium oxide contents. FIGS. 4A-D show the X-ray patterns of doped In2O3 thin films with different post annealing temperatures. FIGS. 5A-D show the resistivity of doped In2O3 thin films with different post annealing temperatures. FIG. 6 shows the resistivity of doped In2O3 thin films with various hafnium oxide contents and post annealing temperatures. FIG. 7 shows a schematic of the present invention resistive oxide ferroelectric transistor. FIGS. 8A-B show the operation of the present invention doped conductive oxide ferroelectric transistor. FIG. 9 shows another embodiment of the present invention doped conductive oxide ferroelectric transistor. FIGS. 10A-F show a representative fabrication process for the gate etching process. FIGS. 11A-K show a representative fabrication process for the replacement gate process. DETAILED DESCRIPTION OF THE INVENTION The ferroelectric transistor of the present invention is a ferroelectric field effect transistor having a resistive oxide layer replacing the gate dielectric. By replacing the gate dielectric with a resistive oxide layer, the ferroelectric layer is electrically connected to the substrate, and thus eliminating the trapped charges effect. Further, by using a resistive oxide layer comprising oxygen component, the silicon interfacial property of the resistive oxide layer is comparable with that of the gate dielectric, and the resistance of the resistive oxide layer would not vary significantly after subsequent processes of anneal and oxygen exposure. The resistance of the resistive oxide layer can be adjustable through fabrication process variations and thus can be optimized to achieve the best performance for the ferroelectric transistor. In the limits of the present invention, when the resistive oxide layer is non-conductive, it behaves as a gate dielectric in a conventional ferroelectric transistor. When the resistive oxide layer is highly conductive (i.e. negligible film resistivity), the ferroelectric transistor behaves as a conductive oxide ferroelectric transistor, disclosed by the same inventors in a co-pending application “Conductive metal oxide gate ferroelectric memory transistor”, hereby incorporated by reference. The disclosed resistive oxide film is substantially ohmic, meaning for a given film thickness, the resistance of the resistive film is substantially constant with respect to the applied voltage (with preferably less than 20% variation), or the current running through the resistive film is substantially linear with respect to the applied voltage. The advantages of using ohmic resistive oxide layer are the ease of fabrication process, the ease of device design and simulation since the I-V characteristics of the resistive oxide film is substantially linear due to the ohmic law, markedly advantageous than non-linear I-V characteristics such as the leakage current generated by a Schottky emission or a Frankel-Poole emission or Fowler-Nordheim tunneling. The resistive oxide film in the present invention is preferably a doped conductive oxide film in which the conductive oxide is doped with an impurity species or a variety of impurity species to modify its resistance. The doped conductive oxide preferably exhibits ohmic behavior, meaning having an I-V characteristic that is substantially linear. The conductive oxide film is preferably a conductive oxide film of any one metal selected from a group of Mo, W, Tc, Re, Ru, Os, Rh, Ir, Pd, Pt, In, Zn, Sn, Sr—Ru or Sr—Co (such as IrO2 and RuO2), or a rock-salt (NaCl) crystal structure face-centered cubic metal oxide, such as NdO, NbO, SmO, LaO, and VO. The preferred method of forming the conductive oxide is by deposition. However, other methods may be used such as doping by diffusion and ion implantation. For example, the conductive oxide can be boron (B) doped or fluorine (F) doped ZnO and antimony (Sb) doped or fluorine (F) doped SnO2. The conductive oxide may be composed of any number of conductive perovskite oxides such as lanthanum strontium cobalt oxide (LSCO). Typical examples of simple perovskite oxides are expressed by the general formula ABO3 such as SrRuO3 or LaNiO3, where AB can be any combination of (A=Ca, Sr) (B═V, Cr, Fe, Ru), (A=La)(B═Ti, Co, Ni, Cu), (A=H, Li, Na, K)(B═Re, Mo, Nb), (A=La1-xSrx)(B═V, Mn, Co). Another example of conductive perovskite oxides is expressed by the general formula A2B2O7 where (A=Bi, Pd)(B═Ru1-xBix, Ru1-xPbx). Examples of layered perovskite oxides include CaTiO, (Sr(Ru, Ir, Cr)O3)(SrO)n such as SrRuO3, SrIrO3, Sr2RuO4, Sr2IrO4 and Ba2RuO4. The conductive oxide film can also include high temperature superconducting oxides such as La1-xSrxCuO4, Nd1-xCexCuO4, YBa2Cu3O7, Bi2Sr2Can-1CunO2n+4, (Nd1-xCex)2CuO4. See, for example, Suzuki, U.S. Pat. No. 6,151,240, entitled “Ferroelectric nonvolatile memory and oxide multi-layered structure”, hereby incorporated by reference. The impurity species is preferably an insulator material, and amorphously distributed throughout the conductive oxide film. The impurity species is preferably an element or its non-conductive oxide such as hafnium or hafnium oxide (HfO2 and its variants of oxygen-rich or oxygen-deficiency HfOx), zirconium or zirconium oxide (ZrO2 and its variants of oxygen-rich or oxygen-deficiency ZrOx), lanthanum or lanthanum oxide (LaO2 and its variants of oxygen-rich or oxygen-deficiency LaOx), or aluminum or aluminum oxide (Al2O3 and its variants of oxygen-rich or oxygen-deficiency AlOx). The conductive oxide is most preferred to be In2O3 with the dopant species being hafnium, zirconium, lanthanum, aluminum or their oxides. Doping with an element, for example hafnium, will likely generate hafnium oxide due to the presence of oxygen in the conductive oxide film. The following experiment demonstrates the feasibility of the fabrication of a typical resistive oxide film of conductive oxide In2O3 doped with hafnium/hafnium oxide where its phase, grain size and resistance can be controlled by various deposition parameters and post annealing process conditions. The doped indium oxide film is deposited by sputtering (physical vapor deposition, PVD) process in this experiment, but other deposition processes such as chemical vapor deposition (CVD), evaporation, atomic layer deposition (ALD) can be used. Using an indium target together with a hafnium target in the presence of oxygen plasma, hafnium/hafnium oxide doped indium oxide films with various physical and electrical properties can be fabricated. The deposition conditions are typically 200-300 W of DC sputtering power, 0-60% of oxygen partial pressure, 20-200° C. substrate temperature, 400-850° C. post annealing temperature with silicon, silicon dioxide substrates and with or without platinum or platinum/titanium underlayer. The silicon substrate can be cleaned in HF (50:1) for 5 seconds before indium oxide deposition. FIG. 3 shows the X-ray patterns of doped In2O3 thin films deposited on platinum substrate with various percentage (0, 10, 20, and 30%) of hafnium oxide at substrate temperature of 200° C. With increased percentage of hafnium oxide dopant, only the peaks of indium thin film decrease without any indication of hafnium oxide peaks, indicating that hafnium oxide exists in the In2O3 thin film as amorphous state. FIGS. 4A, 4B, 4C, and 4D show the X-ray patterns of un-doped, 10% doped, 20% doped, and 30% doped In2O3 thin films at various annealing temperatures (400-800° C.) respectively, showing the effects of post annealing on the phase transformation of indium oxide thin film deposited on Pt. When deposited, the thin film consists of indium oxide phase with oxygen deficiency. After annealing at 400° C. for 5 minutes in oxygen ambient, the oxygen-poor indium oxide film is mostly transform into stochiometric indium oxide (In2O3) film. The In2O3 peaks increase with increasing annealing temperatures, which means the grain size of In2O3 thin film increases with increasing annealing temperatures. There are no peaks of hafnium oxide, thus the hafnium oxide exists in indium oxide film as an amorphous state. Even at the annealing temperature of 800° C. for 5 minutes, the hafnium oxide is still amorphous. The effects of post annealing temperatures on the resistivity of indium oxide are shown in FIGS. 5A, 5B, 5C, and 5D for un-doped, 10% doped, 20% doped, and 30% doped In2O3 thin films respectively. After annealing in oxygen ambient for 5 minutes, the resistivity increases with increasing annealing temperature due to the indium oxidation. After reaching the maximum value at around 600° C. for un-doped indium oxide film and 400° C. for doped indium oxide films, the resistivity decreases with increasing temperatures due to the growth of the grain size. FIG. 6 shows the dependencies of doped indium oxide resistivity with respect to dopant concentrations and post anneal temperatures. These data indicate that various physical and electrical properties of a resistive oxide film can be achieved by doping a conductive oxide layer with selective impurity species. Employing a doped conductive oxide film as a gate dielectric for the ferroelectric transistor, the first embodiment of the present invention is shown in FIG. 7, illustrating an n-channel doped conductive oxide gate ferroelectric transistor. The gate stack of the present invention comprises a top gate electrode 61, a ferroelectric film 62, a bottom gate electrode 68 and a doped conductive oxide gate 51, positioning on a p-type silicon substrate 63, and disposed between the source 64 and drain 65 regions having a high concentration of n-type impurity ions. The ferroelectric transistor is isolated by the isolation trenches 66. The gate insulator of the present invention transistor is replaced with a doped conductive oxide such as hafnium (or Zr, La, or Al) oxide doped In2O3 to prevent floating gate effect. FIGS. 8A and 8B show the operation of the above n-channel doped conductive oxide ferroelectric transistor. In FIG. 8A, when a positive voltage is applied to the gate electrode 61, polarization of the ferroelectric film 62 occurs with electrons pulled to the top and holes pulled to the bottom of the ferroelectric film. Electrons are then accumulated at the doped conductive oxide and the surface of the silicon under the ferroelectric gate stack. This forms a high conductive channel 67. Therefore the ferroelectric transistor is “ON”, i.e. if a voltage bias is placed across the source 64 and the drain 65, a current will flow through the transistor. The ferroelectric transistor memory is nonvolatile, meaning that the transistor remains in the ON state even after this positive voltage is removed due to the remnant polarization of the ferroelectric film 62. In FIG. 8B, when a negative voltage is applied to the gate electrode 61, opposite polarization occurs in the ferroelectric film 62 with holes pulled to the top of the ferroelectric gate and electrons pulled to the bottom of the ferroelectric film. Holes then are accumulated at the doped conductive oxide and the surface of the silicon under the ferroelectric gate stack. There are no conduction channel 67, and the ferroelectric transistor is “OFF”, i.e. a non-conduction state takes place between the source 64 and drain 65 regions, and is maintained even after the negative voltage is removed. The doped conductive oxide prevents the bottom electrode 68 from direct contact to the n+ source and drain junctions. Since the bottom electrode 68 is connected to the silicon through the doped conductive oxide 51, the bottom electrode 68 is not electrically isolated, and therefore would not be able to accumulate charges as a floating gate. The charge retention time of this device is thus independent of the current flow through the ferroelectric thin film. In the second embodiment of the invention, the bottom gate electrode is omitted. Thus the gate stack of the doped conductive oxide gate ferroelectric transistor comprises a top gate electrode 161, a ferroelectric film 162, and a doped conductive oxide gate 151 as shown in FIG. 9. The doped conductive oxide in the present invention is preferably a doped conductive metal oxide, but can be without any metal component. The doped conductive oxide can make good interface with the silicon substrate, and can be selected to have a good lattice matching with the deposited ferroelectric film, especially the ones having perovskite crystal structures. Furthermore, a doped conductive oxide serving as electrodes for the ferroelectric film may improve the quality of the ferroelectric film, and thus improving the operation of the ferroelectric transistor. A ferroelectric film is generally formed in an oxidizing ambience such as a deposition process with oxygen as a reactive gas, or an annealing process in an oxygen ambience to improve the stability of the deposited ferroelectric film. Therefore the electrode material for a ferroelectric film is preferable an oxidization resistant noble metal such as Pt and Ir. Doped conductive oxides is already oxidation resistant, and further, due to the high concentration of oxygen, the doped conductive oxide film can suppress the movement and accumulation of oxygen at the ferroelectric/doped conductive oxide interface to improve the reliability such as fatigue and the controllability of the ferroelectric and therefore its polarization property. One further advantage of doped conductive metal oxide is its etch selectivity. Oxygen can be used as an etching gas for doped conductive metal oxides since the steam pressure of metal oxide is typically very high. The doped conductive metal oxide therefore can be etched with higher selective etching rate than other dielectric films. In addition, the doped conductive metal oxide and the metal can have high selective etching rate since the doped conductive metal oxide films (RuO2, for example) normally cannot react easily with halogen such as F and Cl used for etching the metal films. The ferroelectric material disclosed in the present invention is preferably any of the following: Pb(Zr, Ti)O3 (PZT), SrBi2Ta2O9 (SBT), Pb5Ge3O11(PGO), BaTiO3, or LiNbO3, but any ferroelectric material exhibiting hysteresis effect can be employed in the conductive oxide ferroelectric transistor. The preferred ferroelectric compounds are, in order of preference, PGO, SBT and PZT. The bottom electrode and the top electrode are preferably a metal layer such as aluminum, platinum or iridium, and more preferably a conductive layer, a conductive oxide layer, a conductive metal oxide layer, or a multilayer such as conductive oxide/metal, or conductive metal oxide/metal. Within the scope of the invention, the disclosed resistive oxide ferroelectric transistor structure may also incorporate all the advanced features of the state of the art technology such as SOI or SIMOX substrate, halo or LDD source and drain, sidewall spacers for the gate stack, shallow trench isolation (STI) or LOCOS isolation, silicide formation such as titanium silicide, cobalt silicide, or nickel silicide, raised source and drain, passivation, tungsten or aluminum contact, aluminum or copper metallization. The present invention further discloses the fabrication process for the doped conductive oxide ferroelectric transistor. Although the fabrication process for the doped conductive oxide ferroelectric transistor is illustrated and described below with reference to certain specific processes, the present invention is nevertheless not intended to be limited to the details shown. The general process of semiconductor fabrication has been practiced for many years, and due to the multitude of different ways of fabricating a device or structure, various modifications may be made in the fabrication process details within the scope and range of the present invention and without departing from the meaning of the invention. One fabrication process for the doped conductive oxide ferroelectric transistor is a gate etching process, employing an etching process to form the gate stack and comprising the steps of: Preparing a semiconductor substrate Forming a gate stack on the substrate Forming drain and source regions on opposite sides of the gate stack. The device fabrication process is then completed with passivation and interconnect metallization steps. Preparing a Semiconductor Substrate, FIG. 10A: The fabrication process starts with a substrate (p-type or n-type, bulk or silicon-on-insulator, SOI or SIMOX) and any state of the art suitable processes for the well formation and device isolation. FIG. 10A shows a p-type substrate 210 (similar fabrication process can be applied to an n-type substrate with appropriate corrections and adjustments) and shallow trench isolation (STI) 216 to form an active device area 214. For simplicity, important but unrelated details such as periphery devices, well formation process and active region threshold voltage adjustment, are not shown. Forming a Gate Stack on the Substrate, FIG. 10B: Then the gate stack multilayer of doped conductive oxide/bottom electrode/ferroelectric film/top electrode is deposited. In the second embodiment of the invention, the bottom electrode is omitted, and the gate stack multilayer comprises only of three layers: doped conductive oxide, ferroelectric film, and top electrode. The doped conductive oxide is perferably between 10 to 30 nm thick and is preferably hafnium oxide, zirconium oxide, lanthanum oxide or aluminum oxide doped In2O3, but can be any doped conductive oxide or resistive oxide materials as disclosed above. The bottom electrode is perferably between 50 to 200 nm thick and is perferably platinum or iridium, but can also be any conductive metal or conductive oxide materials. The ferroelectric layer is perferably between 50 to 300 nm thick and is perferably PGO, BST or PZT, but can be any ferroelectric material exhibiting hysteresis effect. The top electrode is perferably between 50 to 200 nm thick and is perferably aluminum, platinum or iridium, but can also be any conductive metal or conductive oxide materials. Furthermore, the electrode layers (either the bottom or the top electrode) can be a multilayer of metal and conductive oxide. The gate stack multilayer is then patterned into a ferroelectric gate stack, comprising a top electrode 213, a ferroelectric 212, a bottom electrode 211, and a doped conductive oxide 201 as shown in FIG. 10B. The patterning of the gate stack multilayer is preferably by photolithography where a patterned mask is provided on the gate stack multilayer, then the gate stack multilayer is etched according to the pattern mask, and then the patterned mask is removed. The patterned mask is preferably a photoresist layer, coated and exposed to UV light under a photo mask to transfer a pattern from the photo mask onto the photoresist. The photoresist mask protects the gate stack multilayer during an etch step to transfer the pattern from the photoresist onto the gate stack multilayer. And then the photoresist mask can be stripped. The gate stack multilayer etching is preferably accomplished by reactive ion etching or by wet etches. The next step is lightly doping drain (LDD) ion implantation into source 218 and drain 219 regions, although the ferroelectric memory transistor may or may not requires this LDD ion implantation. LDD implantation includes implantation of phosphorus ions at an energy level of 15 keV to 40 keV, or arsenic ions at an energy level of 30 keV to 60 keV. The doses of the LDD phosphorus or arsenic implantation are about 5×1014 cm−2 to 1015 cm−2 (FIG. 10C), though the specific energy and dose values can be adjusted for optimizing the ferroelectric transistor operation. The next step is sidewall spacer formation. A layer of dielectric material such as silicon nitride or silicon dioxide is deposited onto the gate stack to a thickness of about between 20 to 80 nm, and then is anisotropic etched to leave a dielectric sidewall spacer 220 on the ferroelectric gate stack (FIG. 10D). Forming Drain and Source Regions on Opposite Sides of the Gate Stack, FIG. 10E. Then a source region 221 and a drain region 222 are formed by implantation of doping ions, for example arsenic at a dose of about 1015 cm−2 to 5×1015 cm−2 and at an energy level of 15 keV to 30 keV (FIG. 10E). The device fabrication process is then completed with passivation and interconnect metallization steps, FIG. 10F. A passivation layer 235 such as silicon dioxide is deposited on the whole structure to a thickness of about 1000 to 2000 nm. The passivation layer may be planarized to improve the topology of the device. The structure is then annealed at a temperature of between about 400° C. to 500° C. for about 15 to 60 minutes. The passivation layer is then patterned, preferably by photolithography, to form contact holes, and then the fabrication process continued with first level metallization contact 241 to source 221, contact 243 to gate stack (top electrode 213, ferroelectric 212, bottom electrode 211 and doped conductive oxide 201), contact 242 to drain 222. The gate etching process for the second embodiment of the present invention (the ferroelectric transistor with the gate stack of top electrode/ferroelectric/doped conductive oxide) is similar to the above gate etching process, with the exception of the omission of the bottom gate electrode steps, meaning no bottom gate electrode deposition and no bottom gate electrode etching. Alternatively, the ferroelectric gate stack may be fabricated by a replacement gate process similar to Hsu et al., U.S. Pat. No. 6,274,421, entitled “Method of making metal gate sub-micron MOS transistor”, hereby incorporated by reference. The fabrication process uses a replacement process to form the gate stack and comprises the steps of: Preparing a semiconductor substrate Forming a replacement gate stack comprising a sacrificial layer Forming drain and source regions on opposite sides of the replacement gate stack Filling the areas surrounding the replacement gate stack while exposing a top portion of the replacement gate stack Removing the sacrificial layer portion of the replacement gate stack Forming the remainder of the gate stack. The device fabrication process is then completed with passivation and interconnect metallization steps. Preparing a Semiconductor Substrate, FIG. 11A: Similar to the gate etching process, the fabrication process starts with preparing a substrate (p-type or n-type, bulk or silicon-on-insulator, SOI or SIMOX) and any state of the art suitable processes for the well formation and device isolation. FIG. 11A shows a p-type substrate 310 (similar fabrication process can be applied to an n-type substrate with appropriate corrections and adjustments) and shallow trench isolation (STI) 316 to form an active device 314. For simplicity, important but unrelated details such as periphery devices, well formation process and active region threshold voltage adjustment, are not shown. Forming a Replacement Gate Stack Comprising a Sacrificial Layer on the Substrate, FIG. 11B: Then the multilayer replacement gate stack is deposited. The replacement gate stack serves as a place holder for the continued fabrication of the device, and will be removed before the fabrication of the functional gate stack. Thus the multilayer replacement gate stack comprises the first two layers (doped conductive oxide and bottom electrode) of the multilayer gate stack, and a sacrificial gate replacement layer. In the second embodiment of the invention where the bottom electrode of the gate stack is omitted, the replacement gate stack comprises only the doped conductive oxide layer and the sacrificial gate replacement layer. The doped conductive oxide is perferably between 10 to 30 nm thick and is preferably hafnium oxide, zirconium oxide, lanthanum oxide or aluminum oxide doped In2O3, but can be any doped conductive oxide or resistive material as disclosed above. The bottom electrode is perferably between 50 to 200 nm thick and is perferably platinum or iridium, but also can be any conductive material. The sacrificial gate replacement layer is preferably between about 100 to 300 nm thick and is preferably silicon nitride or silicon dioxide. Since the sacrificial gate replacement layer serves as a place holder for the functional gate stack, the thickness of the sacrificial layer is partially determined by the total thickness of the remainder of the functional gate stack. The replacement gate stack multilayer is then patterned into a ferroelectric gate stack, comprising a replacement gate layer 330, a bottom electrode 311, and a doped conductive oxide 301 as shown in FIG. 11B. The patterning of the gate stack multilayer is preferably by photolithography and reactive ion etching. The next step is lightly doping drain (LDD) ion implantation into source 318 and drain 319 regions, although the ferroelectric memory transistor may or may not require this LDD ion implantation. LDD implantation includes implantation of phosphorus ions at an energy level of 15 keV to 40 keV, or arsenic ions at an energy level of 30 keV to 60 keV. The doses of the LDD phosphorus or arsenic implantation are about 5×1014 cm−2 to 1015 cm−2 (FIG. 11C). Then a layer of dielectric material such as silicon nitride or silicon dioxide is deposited onto the replacement gate stack to a thickness of about between 20 to 80 nm, and then is anisotropic etched to leave a dielectric sidewall spacer 320 on the ferroelectric gate stack (FIG. 11D). Forming Drain and Source Regions on Opposite Sides of the Replacement Gate Stack, (FIG. 11E): Then a source region 321 and a drain region 322 are formed by implantation of doping ions, for example arsenic at a dose of about 1015 cm−2 to 5×1015 cm−2 and at an energy level of 15 keV to 30 keV. Filling the Areas Surrounding the Replacement Gate Stack While Exposing a Top Portion of the Replacement Gate Stack, FIG. 11F: A dielectric layer 335 such as silicon dioxide is deposited on the whole structure. The dielectric layer is then planarized, preferably by a chemical mechanical polishing (CMP) process. The thickness of the dielectric layer is preferably about 50% thicker than the replacement gate layer 330 to prevent dishing during planarization. Removing the Sacrificial Layer Portion of the Replacement Gate Stack, FIG. 11G: The replacement gate layer 330 is removed to expose a gate trench 337, preferably by a wet etch process to prevent damage to the surrounding structure. An optional spacer 340 can be formed in the sidewall of the gate trench. The spacer formation is preferably by depositing a layer of silicon nitride of about 10 to 30 nm thick, and then anisotropically etched (FIG. 11H). Forming the Remainder of the Gate Stack, FIG. 11I: The ferroelectric layer is then deposited into the gate trench. The ferroelectric layer is perferably PGO, BST or PZT, but can be any ferroelectric material exhibiting hysteresis effect. The thickness of the ferroelectric layer is preferably slightly thicker than the depth of the gate trench to minimize the dishing effect during the subsequent CMP process of planarizing the ferroelectric layer 312. The top electrode 313 is then fabricated on the feroelectric layer 312. The top electrode formation is preferably by depositing a blanket layer of top eletrode material, and then is patterned into the top electrode, preferably by photolithography and reactive ion etching techniques (FIG. 11J). The top electrode is perferably between 50 to 200 nm thick and is perferably aluminum, platinum or iridium, but also can be any conductive material. The device fabrication process is then completed with passivation and interconnect metallization steps, FIG. 11K. A passivation layer such as silicon dioxide is deposited on the whole structure to a thickness of about 300 to 500 nm. The structure is then annealed at a temperature of between about 400° C. to 500° C. for about 15 to 60 minutes. The passivation layer is then patterned, preferably by photolithography, to form contact holes, and then the fabrication process continued with first level metallization contact 341 to source 321, contact 343 to gate stack (top electrode 313, ferroelectric 312, bottom electrode 311 and doped conductive oxide 301), contact 342 to drain 322. The replacement gate process for the second embodiment of the present invention (the ferroelectric transistor with the gate stack of top electrode/ferroelectric/doped conductive oxide) is similar to the above replacement process, with the exception of the omission of the bottom gate electrode steps, meaning no bottom gate electrode deposition and no bottom gate electrode etching. Thus a novel ferroelectric transistor and its memory cell application has been disclosed, together with the method of device fabrication. It will be appreciated that though preferred embodiments of the invention have been disclosed, further variations and modifications thereof may be made within the scope of the invention as defined in the appended claims. Further, although the invention has been described with reference to a ferroelectric transistor for use with nonvolatile memory applications, other applications of the inventive concepts disclosed herein will also be apparent to those skilled in the art. | <SOH> BACKGROUND OF THE INVENTION <EOH>Ferroelectric materials are composed of many randomly-distributed permanently polarized regions. Under the presence of an electric field, the regions with a polarization component in the direction of the electric field grow at the expense of the non-aligned regions so that a net polarization can result. If the electric field decreases, the polarization also decreases but at a slower rate so that even when the electric field becomes zero, a remnant polarization remains. A negative coercive field is required to bring the polarization to zero. This hysteresis behavior of a ferroelectric material is the basis of ferroelectric nonvolatile memory devices. Currently there are two types of ferroelectric nonvolatile memory devices: ferroelectric capacitor which uses a transistor to detect the polarization of a ferroelectric capacitor, and ferroelectric transistor which detects a change in the transistor conductance caused by the polarization of a ferroelectric gate material. The ferroelectric transistor is much more advantageous than the ferroelectric capacitor due to the smaller surface area which enables higher density memory chip, and the non-destructive readout which significantly reduces the fatigue problem. The ferroelectric transistor is typically a ferroelectric-gate-controlled semiconductor field-effect transistor (FET), which employs a ferroelectric film in the gate stack of the FET, and in which a proper polarization of the ferroelectric film can create an inversion layer in the channel region of the transistor. The basic ferroelectric-gate controlled field-effect transistor is a metal-ferroelectric silicon (MFS) FET. The term MFS represents the layers in the gate stack of the ferroelectric transistor. Thus the gate stack of the MFS transistor consists of a metal (M) gate electrode disposed on a ferroelectric (F) gate dielectric on the silicon (S) channel of the transistor. FIG. 1 shows the schematic of an n-channel MFS transistor. A ferroelectric film 12 is formed as a gate insulating film on a p-type silicon substrate 13 , together with source 14 and drain 15 regions having a high concentration of n-type impurity ions. A metal gate electrode 11 is formed over the ferroelectric film 12 . The MFS transistor is isolated by the isolation trenches 16 . However, effective transistor operation of the above MFS transistor is difficult to achieve due to the requirement of the ferroelectric/silicon interface. When a ferroelectric film is deposited directly on the silicon substrate, metals and oxygen from the ferroelectric layer may diffuse into the ferroelectric-silicon interface, creating interface trapped charges which affect the polarization of the ferroelectric film, and overall may make the operation of the ferroelectric transistor unstable. Further, since the thermal expansion coefficient and lattice structure of a ferroelectric film is not compatible with silicon, it is very difficult to form a high-quality ferroelectric film with a clean interface directly on the silicon substrate. To address the drawbacks posed by the direct ferroelectric/silicon interface, a gate dielectric can be inserted between the ferroelectric film and the silicon substrate. The ferroelectric transistor is then called metal-ferroelectric-oxide (or insulator) silicon (MFOS or MFIS) FET. FIG. 2A shows a MFOS memory transistor using a gate oxide layer 27 formed between the silicon substrate 13 and the ferroelectric film 12 . Alternatively, a metal floating gate layer 28 can be added between the ferroelectric film 12 and the gate oxide layer 27 as shown in FIG. 2B for a metal-ferroelectric-metal-oxide (or insulator) silicon (MFMOS or MFMIS) transistor. A suitable conducting material (e.g. Pt or Ir) is normally selected for the floating gate 28 to allow the deposition of the ferroelectric thin film and to prevent diffusion of the ferroelectric material into the gate dielectric and the channel. The floating gate layer 28 is also called bottom electrode, or bottom gate, in reference to the other gate electrode 11 , called top electrode, or top gate. Such gate stack structures (metal-ferroelectric-oxide gate stack or metal-ferroelectric-metal-oxide gate stack) overcome the surface interface and surface state issues of a ferroelectric layer in contact with the silicon substrate. However, they incorporate other difficulties such as higher operation voltage and trapped charges in the bottom floating gate layer. The operation voltage of these transistors is higher than the ferroelectric layer programming voltage by an amount of the voltage across the gate dielectric. And when there is a voltage applied across the ferroelectric thin film, there will be current flow in the gate stack, and charges would be trapped in this floating electrode. The trapped charges may neutralize the polarization charges at the interface of the bottom electrode and the ferroelectric film and could shorten the memory retention time of this structure. Various prior designs have been disclosed to compensate for the trapped charges in the floating bottom electrode. One of the prior art design to reduce the trapped charges in the lower electrode is the formation of a Schottky diode such as a metal-ferroelectric-metal silicon (MFMS) device disclosed in Nakao et al., U.S. Pat. No. 5,303,182, entitled “Nonvolatile semiconductor memory utilizing a ferroelectric film”. A Schottky barrier is formed between the bottom metal electrode of the gate unit (or a very shallow junction layer) and the silicon substrate. The Schottky ferroelectric gate memory transistor requires a space between the bottom electrode and the source and drain region or a very shallow n-channel under the gate, therefore the drive current of the Schottky ferroelectric gate memory transistor can be relatively low. Hsu et al., U.S. Pat. No. 5,731,608, entittled “One transistor ferroelectric memory cell and method of making the same”, and its continuations and divisions (U.S. Pat. Nos. 5,962,884; 6,117,691; 6,018,171; 5,942,776; 5,932,904; 6,146,904; 6,011,285; 6,531,325), hereby incorporated by reference, disclose a distance between 50 to 300 nm from the bottom metal electrode to the source and drain to reduce the possible high leakage current due to the increased field intensity at the metal edge of the Schottky diode because of the sharp edge at the periphery of the metal contact. Alternatively, Willer et al., U.S. Pat. No. 6,538,273, entittled “Ferroelectric transistor and method for fabricating it”, discloses a recess of the source and drain below the surface of the semiconductor surface in a Schottky ferroelectric gate memory transistor. Another design to reduce the trapped charges in the lower electrode is to provide a conduction path for the lower electrode. Black et al., U.S. Pat. No. 6,069,381, entitled “Ferroelectric memory transistor with resistively coupled floating gate” discloses an integrated resistor in the form of a spacer between the bottom floating gate electrode and the source/drain to remove the trapped charges. Moise et al., U.S. Pat. No. 6,225,655 and its continuation U.S. Pat. No. 6,362,499, entitled “Ferroelectric transistors using thin film semiconductor gate electrodes” disclose an external resistor connecting the lower electrode to ground to drain the trapped charges. This additional resistor ensures that the potential of the floating gate will approach that of the source/drain region after a certain delay time, but this could affect the high speed switching characteristic of the ferroelectric memory. Yoo, U.S. Pat. No. 5,812,442, entitled “Ferroelectric memory using leakage current and multi-numerical system ferroelectric memory” discloses a leakage gate dielectric to remove the trapped charges through the silicon channel. The leakage current is generated by a Schottky emission or a Frankel-Poole emission or Fowler-Nordheim tunneling to reduce the bound charges in the bottom metal electrode. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention discloses a novel design to reduce the trapped charges in the ferroelectric transistor operation by the use of a resistive oxide film in place of the gate dielectric, fabricated with proper resistance value to optimize the performance of the ferroelectric transistor. By replacing the gate dielectric with a resistive oxide film, and by optimizing the value of the film resistance, the bottom gate of the ferroelectric layer is electrically connected to the silicon substrate, therefore the floating gate effect can be eliminated, resulting in the improvement of the memory retention characteristics. Furthermore, the operating voltage for the ferroelectric transistor can be reduced because of the absence of the gate dielectric The resistive oxide film is preferably a doped conductive oxide which is a conductive oxide doped with an impurity species. By varying the dopant concentration and other fabrication process parameters, the resistive oxide film can achieve a wide range of resistance suitable for the optimization of the ferroelectric transistor performance. The doped conductive oxide is most preferred to be In 2 O 3 with the dopant species being hafnium oxide, zirconium oxide, lanthanum oxide, or aluminum oxide. The present invention ferroelectric transistor can be a metal-ferroelectric-metal-doped conductive oxide silicon (MFMRS) FET. The gate stack of the MFMRS transistor has a top metal electrode (or top gate) disposed on a ferroelectric layer disposed on a bottom metal electrode (or bottom gate) disposed on a doped conductive oxide layer on the silicon substrate. The present invention ferroelectric transistor can also be a metal-ferroelectric-doped conductive oxide silicon (MFRS) FET. The gate stack of the MFRS transistor has a top metal electrode (or top gate) disposed on a ferroelectric layer disposed on a doped conductive oxide layer on the silicon substrate. The resistive doped conductive oxide further can have the advantages of possible lattice matching with the ferroelectric layer, reducing or eliminating the oxygen diffusion problem at the ferroelectric interface to improve the reliability of the ferroelectric transistor, and possible etch selectivity improvement with other dielectric and metal films. The fabrication process of the present invention ferroelectric transistor can be performed by a gate etching process or by a replacement gate process. In the gate etching process, the multilayer gate stack is deposited and etched, while in the replacement gate process, a replacement gate stack is deposited as a place holder for the fabrication of other portions of the device, then the replacement gate stack is removed and the functional gate stack is deposited. | 20040112 | 20060307 | 20050714 | 83468.0 | 0 | QUACH, TUAN N | IN2O3 THIN FILM RESISTIVITY CONTROL BY DOPING METAL OXIDE INSULATOR FOR MFMOX DEVICE APPLICATIONS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,755,519 | ACCEPTED | Toy glider | A toy glider including a shaft, a roller attached to a first end of the shaft, and a housing attached to a second opposing end of the shaft. The roller, a front end portion of the housing, and other portions of the toy glider are interchangeable to create a variety of different designs. | 1. A toy glider comprising: a shaft; a roller attached to a first end of the shaft; and a housing attached to a second opposing end of the shaft. 2. The toy glider of claim 1, further comprising a front end coupled to the housing. 3. The toy glider of claim 1, further comprising a sound pad coupled to the housing. 4. The toy glider of claim 1, further comprising a light pad coupled to the housing. 5. The toy glider of claim 1, wherein the roller comprises at least one wheel and an axle. 6. The toy glider of claim 1, further comprising at least one decorative member coupled to the housing. 7. The toy glider of claim 1, further comprising at least one decorative member coupled to the roller. 8. The toy glider of claim 1, further comprising at least one handle coupled to the housing. 9. The toy glider of claim 6, wherein the at least one decorative member coupled to the housing comprises a front end made to resemble the front end of a jet. 10. The toy glider of claim 6, wherein the at least one decorative member coupled to the housing comprises a front end made to resemble the front end of an automobile. 11. The toy glider of claim 6, wherein the at least one decorative member coupled to the housing comprises at least one wing. 12. The toy glider of claim 6, wherein the at least one decorative member coupled to the roller comprises at least one wing. 13. The toy glider of claim 1, wherein the housing includes at least one handle for grasping the toy glider. 14. A method for manufacturing a toy glider comprising the steps of: providing a shaft; coupling at least one roller to a first end of the shaft; and, coupling at least one housing to a second opposing end of the shaft. 15. The method of claim 14, comprising the further step of: coupling a decorative front end to the housing. | FIELD OF THE INVENTION This present invention relates to toys, and in particular, to a toy glider. BACKGROUND OF THE INVENTION Stick horses have been popular toys with children for many years. Stick horses essentially comprises a wooden stick with a plush horse head attached to one end. The idea behind the stick horse is that children place the wooden stick portion between their legs and ‘pretend’ to ride the horse. Although the stick horse was a popular toy for many years, it is also a very outdated toy. Due to the fact that horses have been replaced as a means of transportation in modem society with automobiles, motorcycles, bus and planes, to name a few, the viability of a toy horse is diminished. With the modernization of transportation, children are more likely to gravitate to modem vehicles as playthings. Although there exist toy cars and the like, there are presently no commercially available simple toys which allow children to ‘pretend’ to drive or pilot modem vehicles, such as cars, trucks, and airplanes. Thus, there is presently a need for toy which simulates this experience for children. SUMMARY OF THE INVENTION An exemplary embodiment of the present invention comprises a toy glider including a shaft, a roller attached to a first end of the shaft, and a housing attached to a second opposing end of the shaft. An exemplary embodiment of the present invention also comprises a method for manufacturing a toy glider including the steps of providing a shaft, coupling at least one roller to a first end of the shaft, and coupling at least one housing to a second opposing end of the shaft. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a left side view showing a toy glider according to a first exemplary embodiment of the present invention. FIG. 2 is a back side isometric view showing the toy glider of FIG. 1. FIG. 3 is a back side isometric view showing the toy glider of FIG. 1. FIG. 4 is a left side exploded view showing the toy glider of FIG. 1. FIG. 5 is a top side exploded view showing the toy glider of FIG. 1. FIG. 6 is a front view showing the toy glider of FIG. 1. FIG. 7 is a rear view showing the toy glider of FIG. 1. FIG. 8 is a top view showing the toy glider of FIG. 1. FIG. 9 is a bottom view showing the toy glider of FIG. 1. FIG. 10 is an exploded view of exemplary embodiments of the toy glider showing interchangeable parts. FIG. 11 is front view of a toy glider according to a second exemplary embodiment of the present invention. FIG. 12 is a rear view of a the toy glider of FIG. 11. FIG. 13 is a front perspective view of the toy glider of FIG. 11. FIG. 14 is a rear perspective view of the toy glider of FIG. 11. FIG. 15 is a left side view of the toy glider of FIG. 11. FIG. 16 is a top view of the toy glider of FIG. 11. FIG. 17 is a bottom view of the toy glider of FIG. 11. FIG. 18 is an exploded view of the toy glider of FIG. 11. FIG. 19 is front view of a toy glider according to a third exemplary embodiment of the present invention. FIG. 20 is a rear view of a the toy glider of FIG. 19. FIG. 21 is a front perspective view of the toy glider of FIG. 19. FIG. 22 is a rear perspective view of the toy glider of FIG. 19. FIG. 23 is a left side view of the toy glider of FIG. 19. FIG. 24 is a top view of the toy glider of FIG. 19. FIG. 25 is a bottom view of the toy glider of FIG. 19. FIG. 26 is an exploded view of the toy glider of FIG. 19. FIG. 27 is front view of a toy glider according to a fourth exemplary embodiment of the present invention. FIG. 28 is a rear view of a the toy glider of FIG. 27. FIG. 29 is a front perspective view of the toy glider of FIG. 27. FIG. 30 is a rear perspective view of the toy glider of FIG. 27. FIG. 31 is a left side view of the toy glider of FIG. 27. FIG. 32 is a top view of the toy glider of FIG. 27. FIG. 33 is a bottom view of the toy glider of FIG. 27. FIG. 34 is an exploded view of the toy glider of FIG. 27. FIG. 35 is front view of a toy glider according to a fifth exemplary embodiment of the present invention. FIG. 36 is a rear view of a the toy glider of FIG. 35. FIG. 37 is a front perspective view of the toy glider of FIG. 35. FIG. 38 is a rear perspective view of the toy glider of FIG. 35. FIG. 39 is a left side view of the toy glider of FIG. 35. FIG. 40 is a top view of the toy glider of FIG. 35. FIG. 41 is a bottom view of the toy glider of FIG. 35. FIG. 42 is an exploded view of the toy glider of FIG. 35. FIG. 43 is front view of a toy glider according to a sixth exemplary embodiment of the present invention. FIG. 44 is a rear view of a the toy glider of FIG. 43. FIG. 45 is a front perspective view of the toy glider of FIG. 43. FIG. 46 is a rear perspective view of the toy glider of FIG. 43. FIG. 47 is a left side view of the toy glider of FIG. 43. FIG. 48 is a top view of the toy glider of FIG. 43. FIG. 49 is a bottom view of the toy glider of FIG. 43. FIG. 50 is an exploded view of the toy glider of FIG. 43. DETAILED DESCRIPTION FIGS. 1-3 show a toy glider 100 according to a first exemplary embodiment of the present invention. FIG. 1 shows a left side view of the toy glider 100, and FIGS. 2 and 3 show isometric views. The toy glider 100 comprises a shaft 110, a roller 120, a housing 130, a front end 140 and a sound and/or light pad 150. The shaft 110 may comprise a unitary member, or may comprises a two-piece ‘snap-fit’ construction, as is well known in the art. The roller 120 is coupled to a first end 111 of the shaft 110 and includes at least one wheel 121, which may be held in place by an axle (now shown) disposed in the roller body. The roller 120 may also include optional decorative members, such as decorative wings 122, 123 shown. As will be explained in detail below, the decorative wings 122, 123 may comprise a plurality of different designs, such as for example, the tail wings of a jet plane (or spaceship), the bumper and/or tail lights of an automobile, or other various designs. The housing 130 preferably includes handles 133, 134 for grasping and holding the toy glider 100. As with the roller 120, the housing 130 may also include optional decorative members, such as decorative wings 136 shown. As will be explained in detail below, the decorative wings 136 may comprise a plurality of different designs, such as for example, the wings of a jet plane (or spaceship), the rear view mirrors of an automobile, or other various designs. The front end 140 preferably includes a toy windscreen 141 and a decorative bumper 142. As will be explained in detail below, the decorative bumper 142 may comprise a plurality of different designs, such as for example, the front end of a jet plane, the front end of an automobile, or other various designs. The sound and/or light pad 150 may be configured to emit sounds, light displays, or both. The sound and/or light pad 150 may also include buttons, switches or other members which serve to actuate the sound and/or light displays. For example, if the toy glider 100 is made to resemble a police car, the sound and/or light pad 150 may include a ‘siren’ sound and flashing red lights. As shown in FIGS. 4 and 5, the housing 130 may be formed of left half piece 131, and a right half piece 132 which are preferably coupled together at one end of the shaft 110, so as to secure a second end 112 of the shaft 110 therebetween. As also shown in FIGS. 4 and 5, the first end 111 of the shaft 110 may be disposed and secured within an opening in the roller 120. FIGS. 6-9 show additional views of the toy glider 100. In particular, FIG. 6 shows a front view of the toy glider 100, and FIG. 7 shows a rear view. FIG. 8 shows a top view of the glider 100, and FIG. 9 shows a bottom view. FIG. 10 is an exploded view of the toy glider 100 showing parts which are interchangeable. For example, although the toy glider 100 is described above as including a roller 120, decorative wings 136, and a decorative bumper 142, and alternate exemplary embodiment of the toy glider 100′ may be manufactured which includes roller 120′, decorative wings 136′, and decorative bumper 142′. As will be noted, the roller 120, decorative wings 136, and a decorative bumper 142 of the toy glider 100 are made to respectively resemble the front end, side wings and rear wings of a jet plane, and the roller 120′, decorative wings 136′, and a decorative bumper 142′ of the toy glider 100′ are made to respectively resemble the front end, rear view mirrors and rear bumper of an automobile. It will be noted by those of ordinary skill in the art that a plurality of different rollers (e.g., 120, 120′), wings (e.g., 136, 136′) and bumpers (e.g., 142, 142′) may be manufactured and provided to make the toy glider resemble different types of vehicles and/or objects (e.g., motorcycle, animal, cartoon character, etc.). The interchangeability of these parts permits the manufacturer of the toy glider to tailor the toy to different child's tastes with minimal effort and expense. In operation, a child straddles the shaft 110 of the toy glider 100 and grasps the handles 133, 134. The child then moves the toy glider around using his or her feet while holding the handle 133, 134. The roller 120 is preferably disposed on the ground during operation, and the wheel 121 thereof rolls along the ground as the child moves the toy glider 100 about. As discussed above, the sound and/or light pad 150 may be activated during operation of the toy glider 100. This may be accomplished either by the actuation of a button, switch or other means by the child, automatically upon movement of the wheel 121, automatically upon grasping of the handles 133, 134, and/or by some other mechanism known to those of ordinary skill in the art. FIGS. 11-18 show a toy glider 200 according to a second exemplary embodiment of the present invention. The toy glider 200 comprises a shaft 210, a roller 220, a housing 230, a front end 240 and a sound and/or light pad 250. The toy glider 200 is similar in appearance to the toy glider 100, and like reference numerals denote like elements. However, the roller 220, handles 233, 234, decorative wings 236 and decorative bumper 242 are made to resemble a spaceship. FIGS. 19-26 show a toy glider 300 according to a third exemplary embodiment of the present invention. The toy glider 300 comprises a shaft 310, a roller 320, a housing 330, a front end 340 and a sound and/or light pad 350. The toy glider 300 is similar in appearance to the toy glider 100, and like reference numerals denote like elements. However, the roller 320, handles 333, 334, decorative wings 336 and decorative bumper 342 are made to resemble a police truck. FIGS. 27-34 show a toy glider 400 according to a fourth exemplary embodiment of the present invention. The toy glider 400 comprises a shaft 410, a roller 420, a housing 430, a front end 440 and a sound and/or light pad 450. The toy glider 400 is similar in appearance to the toy glider 100, and like reference numerals denote like elements. However, the roller 420, handles 433, 434, decorative wings 436 and decorative bumper 442 are made to resemble a motorcycle. FIGS. 35-42 show a toy glider 500 according to a fifth exemplary embodiment of the present invention. The toy glider 500 comprises a shaft 510, a roller 520, a housing 530, a front end 540 and a sound and/or light pad 550. The toy glider 500 is similar in appearance to the toy glider 100, and like reference numerals denote like elements. However, the roller 520, handles 533, 534, decorative wings 536 and decorative bumper 542 are made to resemble a fire truck. FIGS. 43-50 show a toy glider 600 according to a sixth exemplary embodiment of the present invention. The toy glider 600 comprises a shaft 610, a roller 620, a housing 630, a front end 640 and a sound and/or light pad 650. The toy glider 600 is similar in appearance to the toy glider 100, and like reference numerals denote like elements. However, the roller 620, handles 633, 634, decorative wings 636 and decorative bumper 642 are made to resemble a delivery truck. Although the invention has been described in terms of exemplary embodiments, it is not limited thereto. Rather, the appended claims should be construed broadly to include other variants and embodiments of the invention which may be made by those skilled in the art without departing from the scope and range of equivalents of the invention. | <SOH> BACKGROUND OF THE INVENTION <EOH>Stick horses have been popular toys with children for many years. Stick horses essentially comprises a wooden stick with a plush horse head attached to one end. The idea behind the stick horse is that children place the wooden stick portion between their legs and ‘pretend’ to ride the horse. Although the stick horse was a popular toy for many years, it is also a very outdated toy. Due to the fact that horses have been replaced as a means of transportation in modem society with automobiles, motorcycles, bus and planes, to name a few, the viability of a toy horse is diminished. With the modernization of transportation, children are more likely to gravitate to modem vehicles as playthings. Although there exist toy cars and the like, there are presently no commercially available simple toys which allow children to ‘pretend’ to drive or pilot modem vehicles, such as cars, trucks, and airplanes. Thus, there is presently a need for toy which simulates this experience for children. | <SOH> SUMMARY OF THE INVENTION <EOH>An exemplary embodiment of the present invention comprises a toy glider including a shaft, a roller attached to a first end of the shaft, and a housing attached to a second opposing end of the shaft. An exemplary embodiment of the present invention also comprises a method for manufacturing a toy glider including the steps of providing a shaft, coupling at least one roller to a first end of the shaft, and coupling at least one housing to a second opposing end of the shaft. | 20040112 | 20080311 | 20050714 | 74020.0 | 0 | NGUYEN, KIEN T | TOY GLIDER | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,755,527 | ACCEPTED | Cleaning and sanitizing system | A high pressure water stream(14) is discharged onto a surface to be cleaned. An ozone/water stream(16) is discharged on the same surface for sanitizing the surface. The high pressure water and ozone/water streams(14,16) are discharged simultaneously along closely adjacent paths that are either parallel (FIG. 3) or concentric (FIG. 2). The water pressure is at least about 100 p.s.i. and is preferably between 100 p.s.i. and 2000 p.s.i. The nozzles that discharge the streams (14,16) maybe movable relative to the object(s) that receives the high pressure water and ozone/water (FIG. 1). Or, they may be fixed and the object may be movable relative to them (FIG. 4). | 1. A cleaning and sanitizing system, comprising: a first discharge nozzle; a first conduit for delivering water to the first discharge nozzle to be discharged by the first discharge nozzle as a first stream; a second discharge nozzle; a second conduit for delivering ozone/water to the second discharge nozzle, to be discharged from the second discharge nozzle as a stream of ozone/water; a source of water connected to the first conduit for delivering ozone/water into and through the first conduit and out from the first discharge nozzle as a stream of high pressure water; a source of ozone/water connected to the second conduit for delivering ozone/water into and through the second conduit and out from the second discharge nozzle as a stream of ozone/water; said first and second nozzles being positioned relative to each other so that the water and ozone/water streams are contiguous but the ozone is not delivered into the high pressure water stream; and wherein the high pressure water stream is discharged at a high enough pressure that it will exert a cleaning force on a surface to be cleaned and would convert the ozone/water into oxygen if the ozone/water stream were to be delivered into the high pressure water stream; and wherein the high pressure water stream will clean a surface to be cleaned and the ozone/water stream will sanitize the same surface. 2. The system of claim 1, wherein the pressure of the high pressure water stream is at least about 100 psi. 3. The system of claim 1, wherein the pressure of the high pressure water stream is between about 100 psi and about 2000 psi. 4. The system of claim 3, wherein the pressure of the ozone/water stream is lower than the pressure of the high pressure water stream and is sufficiently low that the ozone does not covert to oxygen. 5. The system of claim 1, wherein the second discharge nozzle concentrically surrounds the first discharge nozzle and discharges an ozone/water stream that concentrically surrounds a high pressure water stream that is discharged from the first nozzle. 6. The system of claim 1, wherein the second discharge nozzle is positioned to discharge the stream of ozone/water along a path that is laterally adjacent the path of the high pressure water stream that is discharged from the first discharge nozzle. 7. The system of claim 1, wherein the first and second discharge nozzles are a part of a single wand that has a first end that includes inlets for sections of the first and second conduits that are in the wand and a second end that includes the first and second discharge nozzles. 8. The system of claim 1, wherein the first and second discharge nozzles are fixed in position, and the surface to be cleaned is moved relative to the first and second discharge nozzles. 9. The system of claim 1, wherein said first conduit includes a first hose section and said second conduit includes a second hose section. 10. The system of claim 9, comprising a hose reel on which the two hose sections are wound, said hose reel allowing the hoses to be pulled off from the reel and functioning to rewind the hoses back on the reel when a pull force is removed from the hoses. 11. The system of claim 9, further comprising a single wand that has a first end that includes inlets for sections of the first and second conduits that are in the wand, and a second end that includes the first and second discharge nozzles, wherein the hose sections are connected to the inlets for the sections of the first and second conduits that are in the wand. 12. The system of claim 11, wherein the second discharge nozzle concentrically surrounds the first discharge nozzle and discharges an ozone/water stream that concentrically surrounds a high pressure water stream that is discharged from the first nozzle. 13. The system of claim 1, comprising a closed loop flow path for ozone/water, wherein the second conduit extends from the closed loop path to the second discharge nozzle, and a source of make up ozone/water for adding ozone/water to the system to replace the ozone/water that leaves the path through the second conduit and the second discharge nozzle. 14. The system of claim 13, wherein the high pressure water stream discharging from the first-nozzle is used to aspirate ozone/water from the second discharge nozzle. 15. A method of cleaning and sanitizing an object, comprising: forming wash water into a high pressure first stream and directing it onto the object to be cleaned; forming ozonated water into a second stream and discharging it closely adjacent the first stream of high pressure wash water but without admixing the ozone to the high pressure wash water stream; regulating the pressure of the high pressure wash water stream so that it will exert a cleaning force on the object to be cleaned and would convert the ozone into oxygen if the ozonated water stream were to be delivered into the high pressure wash water stream; and directing the high pressure wash water stream onto the object to be cleaned; and directing the ozonated water stream onto the object after it has been cleaned by the high pressure wash water stream, and using the ozonated water stream to sanitize the same object. 16. The method of claim 15, wherein the pressure of the high pressure water stream is at least about 100 psi. 17. The method of claim 15, wherein the pressure of the high pressure wash water stream is between about 100 psi and about 2000 psi. 18. The method of claim 17, wherein the pressure of the ozonated water stream is smaller than the pressure of the high pressure water stream. 19. The method of claim 15, comprising discharging the ozonated water stream as an annular stream that concentrically surrounds the high pressure wash water stream. 20. The method of claim 15, comprising discharging the stream of ozonated water along a path that is laterally adjacent the path of the high pressure wash water stream. 21. The method of claim 15, comprising providing a closed flow path for the ozonated water, and removing some of the ozonated water from the flow path to form the second stream that is discharged closely adjacent the first stream of high pressure wash water. 22. The method of claim 21, comprising admixing additional ozonated water to the closed loop flow path to make up for the ozonated water that is removed and discharged as the ozonated water stream. 23. The method of claim 21, comprising locating an ozonated water generator in the closed loop flow path, and providing the closed loop flow path with a pump for moving ozonated water from the ozonated water generator through the closed loop flow path and back to the ozonated water generator. 24. A cleaning system, comprising: a wand having a first conduit with an inlet and an outlet, and a first discharge nozzle connected to the outlet of the first conduit; a source of high pressure water connected to the wand; and a source of ozone/water connected to the wand. 25. The cleaning system of claim 24, wherein the source of high pressure water is connected to the first conduit for delivering the high pressure water through the first conduit and the first discharge nozzle. 26. The cleaning system of claim 24, wherein the source of ozone/water is connected to the first conduit for delivering the ozone/water through the first conduit and the first discharge nozzle. 27. The cleaning system of claim 24, further comprising a valve attached to the wand for controlling the flow of the high pressure water. 28. The cleaning system of claim 24, further comprising a second conduit having an inlet and an outlet, and further wherein the source of high pressure water is connected to the inlet of the first conduit and the source of ozone/water is connected to the inlet of the second conduit. 29. The cleaning system of claim 28, further comprising a second discharge nozzle connected to the outlet of the second conduit. 30. The cleaning system of claim 29, wherein the first discharge nozzle is positioned to discharge ozone/water along a path that is substantially parallel to a path of the high pressure that is discharged from the first discharge nozzle. 31. The cleaning system of claim 29, wherein the first discharge nozzle is positioned to discharge ozone/water along a path that is adjacent to a path of the high pressure that is discharged from the first discharge nozzle. 32. The cleaning system of claim 29, wherein the second discharge nozzle substantially concentrically surrounds the first discharge nozzle and discharges an ozone/water stream that substantially concentrically surrounds a high pressure stream that is discharged from the first discharge nozzle. 33. The cleaning system of claim 24, wherein the pressure of the high pressure water is greater than about 100 psi. 34. A cleaning system, comprising: a wand having a grip; a source of ozone/water connected to the wand; a source of high pressure water connected to the wand; a means for delivering the high pressure water from the wand to an object to be cleaned; and a means for delivering the ozone/water from the wand to the object. 35. A cleaning device, comprising: a first fluid inlet; a second fluid inlet; a source of high pressure water connected to first fluid inlet; a source of ozone/water connected to the second fluid inlet; and a first nozzle in fluid communication with at least one of the source of high pressure water or the source of ozone/water, whereby a stream of fluid is directed through the first nozzle. 36. The device of claim 35, further comprising a second nozzle, and wherein the first nozzle is in fluid communication with the source of high pressure water and the second nozzle is in fluid communication with the source of ozone/water. 37. The device of claim 36, wherein a stream of high pressure water emerges from the first nozzle and a stream of ozone/water emerges from the second nozzle, and further wherein the first nozzle and second nozzle are positioned such that the high pressure water stream and ozone/water stream are adjacent one another. 38. A method of cleaning an object, comprising: directing a stream of high pressure water from a hand-held spraying device toward the object; and directing a stream of ozone/water from the hand-held spraying device toward the object. 39. The method of claim 38, wherein the steps of directing a stream of high pressure water and directing a stream of ozone/water are accomplished simultaneously. 40. The method of claim 38, wherein the stream of high pressure water and the stream of ozone/water are substantially parallel to on another. 41. The method of claim 38, wherein the stream of high pressure water is adjacent to the stream of ozone/water without admixing the ozone to the high pressure wash stream. | TECHNICAL FIELD This invention relates to cleaning by use of a high pressure water stream and sanitizing by use of an ozone/water stream. More particularly, it relates to a cleaning and sanitizing method and apparatus in which the high pressure water stream and the ozone/water stream are discharged together, closely adjacent each other but without mixing. BACKGROUND OF THE INVENTION The following United States Patents disclose apparatus and methods of using ozone together with a cleaning fluid: U.S. Pat. No. 5,236,512 granted Aug. 17, 1993, to Ernest E. Rogers, Blaine A. Frandsen and Lamont Hislop; U.S. Pat. No. 5,493,754, granted Feb. 27,1996 to Russell Gurstein and Edgar York; U.S. Pat. No. 5,815,869, granted Oct. 6, 1998 to John M. Hopkins; U.S. Pat. No. 5,839,155, granted Nov. 24, 1998 to Edward D. Berglund, Sung K. Cho and Lowell H. Schiebe; U.S. Pat. No. 6,115,862 granted Sep. 12, 2000 to Theodore R. Cooper, Allyson T. Toney and John B. McParlane; U.S. Pat. No. 6,348,227, granted Feb. 19, 2002, to Luis D. Caracciolo; U.S. Pat. No. 6,455,017, granted Sep. 24, 2002, to John R. Kasting, Dwayne H. Joines and John V. Winings; U.S. Pat. No. 6,458,398, granted Oct. 1, 2002 to Durand M. Smith, Dale S. Winger and Joshua N. Brown, and U.S. Pat. No. 6,638,364, granted Oct. 28, 2003 to Gene Harkins and John M. Hopkins. U.S. Pat. No. 6,454,017 discloses various uses of ozone as a sterilant. In this patent, it is stated that ozone cannot be combined with detergent or other cleaning agents since these are vulnerable to ozone attack. It is also stated that the ozone will destroy both its own effectiveness and that of the cleaning agent rather than attacking pathogens. U.S. Pat. No. 6,455,017 discloses directing a detergent cleaning solution, preferably under pressure, onto a surface to be cleaned. Then following the removal of the soils by the detergent an aqueous ozone rinse is applied to the surface. It is stated that the ozone rinse functions to sanitize the object being cleaned and remove residual detergent. The method of U.S. Pat. No. 6,455,017 involves first directing the cleaning solution onto the surface under pressure, and then rinsing the surface by directing a flow of the ozonated water onto the surface. U.S. Pat. No. 5,865,995, granted Feb. 2, 1999 to William R. Nelson, and U.S. Pat. No. 6,361,688, granted Mar. 26, 2002, also to William R. Nelson, disclose systems for producing “ozonated water”, also termed “ozone/water”. As well be described, the selected one of the systems is combined in a novel way in the system of the present invention. An object of the present invention is to deliver a high pressure cleaning water stream and an ozone/water stream substantially simultaneously to a surface to be cleaned and sanitized. The invention is basically characterized by delivering the high pressure water stream and the ozone/water stream closely adjacent to each other but without mixing. The high pressure water stream removes particles from the surface and the ozone/water stream sanitizes the surface almost simultaneously BRIEF SUMMARY OF THE INVENTION The cleaning and sanitizing system of the present invention is basically characterized by a first discharge nozzle from which a stream of high pressure water is discharged and a second discharge nozzle from which a stream of ozone/water is discharged. The first and second nozzles are positioned adjacent to each other so that the water and ozone/water streams are contiguous but the ozone/water is not delivered into the high pressure water stream. The high pressure water stream is discharged at a pressure high enough that it will exert a cleaning force on a surface to be cleaned and would convert the ozone into oxygen if the ozone/water stream were to be delivered into the high pressure water stream. In preferred form, the pressure of the high water pressure stream is at least about 100 p.s.i. More preferably, the pressure of the high pressure water stream is between 100 p.s.i. and about 2000 p.s.i. The pressure of the ozone/water stream is smaller than the pressure of the high pressure water stream and is sufficiently small that the ozone is not converted into oxygen. According to one aspect of the invention, the ozone/water stream concentrically surrounds the high pressure water stream. According to another aspect of the invention, the high pressure water and the ozone/water are discharged as closely spaced substantially parallel streams. The nozzles for discharging the high pressure water and the ozone/water can be movable to the object that is to be cleaned. Or, the discharge nozzles can be fixed and the article to be cleaned can be moved relative to the nozzles. In an embodiment of the cleaning and sanitizing system of the present invention, a circulating flow path of ozone/water is provided. Along this path, one or more high pressure water discharge nozzles are provided. An ozone/water nozzle is associated with each high pressure water nozzle. The high pressure water stream may be used to “pump” or “aspirate” ozone/water from the circulating system. As ozone/water is removed from the system, new water is delivered to the ozone/water generator and additional ozone is added to the water in the generator. Other objects, advantages, and features of the invention will become apparent. From the description of the best mode set forth below, from the drawings, from the claims and from the principles that are embodied in the specific structure that are illustrated and described. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS Like reference numerals are used to designate like parts throughout the several views of the drawing, and: FIG. 1 is a fragmentary side elevational view showing a workman in the process of cleaning and sanitizing an object, by use of a high pressure water stream and an ozone/water stream; FIG. 2 is a side elevational view of the wand shown in FIG. 1, showing a portion of the wand in longitudinal section, such view showing a first nozzle discharging high pressure water stream surrounded by a second nozzle discharging an ozone/water stream; FIG. 3 is a somewhat schematic view of a second embodiment of the wand, showing the high pressure water nozzle and stream and the ozone/water nozzle and stream in a side-by-side relationship; FIG. 4 is a view of an apparatus in a carcass washing system for conveying chickens, other fowl pork, beef, etc. along a path that is between stationary nozzles for delivering a high pressure water stream, for cleaning the fowl, and an ozone/water stream, for sanitizing the fowl; and FIG. 5 is a flow diagram of a system embodying the present invention. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows a workman 10 holding a wand 12 that is adapted to discharge a high pressure water stream, for cleaning, and an ozone/water stream for sanitizing. The two streams 14, 16 are being discharged against an object 18 that needs to be cleaned and sanitized. FIG. 2 shows the high pressure water stream 14 surrounded by the ozone/water stream 16. FIG. 3 shows the high pressure water stream 14 and the ozone/water stream 16 being discharged in a side by side relationship. Referring to FIG. 2, the wand 12 has a grip portion 20 that the workman 10 grips with one hand 22. The workman's other hand 24 grips an elongated central portion of the wand 12. In this embodiment, the wand 12 includes a conduit 26 that extends through the wand 12 from an inlet 28 to an outlet 30. The inlet 28 is connected to a source of high pressure water 32. The outlet 30 is in the form of a discharge nozzle that discharges a stream of the high pressure water 14. Wand 12 includes a tubular outer wall 34 that surrounds the high pressure water conduit 26. An annular passageway 36 is defined by and radially between the two tubular walls 26, 34. A cone 38 is provided at the outlet of the annular passageway 36. A conduit 40 delivers ozone from a source 42 into the passageway 36. The ozone/water flows through passageway 36, and through diagonal ports in cone 38 and discharges as an annular stream 16 surrounding stream 14. Streams 16, 14 do not directly impinge. They extend substantially parallel to each other along a relative small diameter combined stream path. The conduits 28, 40 includes suitable on-off valves that are not shown. This is because they are not a part of the present invention but can be like the many valves that are available for controlling fluids that flow through conduits. FIG. 3 shows a wand 12 that includes a high pressure water conduit 26′ positioned closely adjacent an ozone/water conduit 36′. As previously described, the high pressure water stream 14 and the ozone/water stream 16 are discharged in close proximity to each other but neither infringes directly on the other. There is no attempt to mix the ozone/water stream 16 with the high pressure water stream 14. As is well known by a person of ordinary skill in the art, the high pressure water conduit 26′ will include an off/on valve and the ozone/water stream 36′ will also include an off/on valve. The valves may also control the pressure and discharge flow rate of the two streams 14, 16, in a known matter. FIG. 1 shows an overhead hose reel 44 on a pulley 46. Pulley 46 is adapted to travel along a rod or a line 48. The reel 44 is preferably a dual reel. It supports a high pressure water hose 50 and an ozone/water hose 52. As the worker 10 walks forwardly from the position shown in FIG. 1, the pulley 46 will move forwardly on the rod or line 48. In a manner that is known to those skilled in the art, a first coiled hose 54 and a second coil holds 56 extend downwardly from the reel 44. The coils 54, 56 are in the nature of coil springs. They will extend when the operator 10 and the wand 12 move forwardly. They will retract when the operator 10 and the wand 14 move rearwardly. FIG. 4 is substantially like FIG. 6 in the aforementioned U.S. Pat. No. 6,348,227 B1. A conveyor 60 is shown conveying a fowl 62 (e.g. chicken or turkey) or some other animal or object along a path, through a processing area between high pressure water and ozone/water streams discharging from nozzles 62. In addition to the nozzles 62, the system 59 may include brushes 64, as described in U.S. Pat. No. 6,348,227 B1. The nozzles 62 are constructed to discharge a stream of high pressure wash water 14 closely adjacent a stream of ozone/water, but without direct mixing of the two streams. As has been described, the high pressure water stream 14 and the ozone/water stream 16 may be brought to the object or article to be cleaned and sanitized. Or, the high pressure water stream 14 and the ozone/water stream 16 may be discharged from stationary nozzles (e.g. nozzles 62) towards a moving object or objects (e.g. fowl that are moved relative to the stationary nozzles 62). FIG. 5 shows a cleaning and sanitizing system that utilizes the present invention. High pressure water is pumped from source 32 into conduit 50 and from conduit 50 to the nozzle 30, 30′ that forms the high pressure water stream 14. Ozonated water (ozone/water) 10 is delivered from apparatus 80 into conduit 52 which leads to the nozzles from the ozone streams 16. The apparatus 80 for admixing ozone to water maybe one of the apparatuses disclosed in the aforementioned U.S. Pat. No. 5,865,995 and U.S. Pat. No. 6,361,688. The contents of these patents are hereby incorporated herein by this specific reference. The ozonated water conduit 52 forms a closed loop with the apparatus 80. A pump 82 pumps the ozone/water in conduit 52 to the recirculated liquid inlet of a contact tank 84. See inlet 112 in U.S. Pat. No. 6,361,688 leading into contact tank 36 disclosed in that patent. The high pressure water stream 14 will pump or aspirate the ozone/water and removed it from the closed loop conduit 52. Because some of the ozonated water is discharged from the water nozzles 30,30′, new water is added at 86 into admixture with the recirculated ozone/water that is moved by pump 82 into the inlet of the contact chamber 84. Preferably, the cleaning water that is discharged from the nozzles 30,30′ is water only. That is, it does not include a detergent or some other chemical. The surface to be cleaned is cleaned by the force of the high pressure water stream rather than by a detergent or other additive to the water stream. The ozone/water stream is delivered directly on the surface that is being cleaned by the water stream and there is no chemical present with which the ozone may react. The illustrated embodiments are only examples of the present invention, and therefore, are non-limitive. It is to be understood that many changes in the particular structure, materials, and features of the invention may be made without departing from the spirit and scope of the invention. Therefore, it is my intention that my patent rights not be limited by the particular embodiments that are illustrated and described herein, but rather are to be determined by the following claims, interpreted according to accepted doctrine of claim interpretation, including the use of the doctrine of equivalence. | <SOH> BACKGROUND OF THE INVENTION <EOH>The following United States Patents disclose apparatus and methods of using ozone together with a cleaning fluid: U.S. Pat. No. 5,236,512 granted Aug. 17, 1993, to Ernest E. Rogers, Blaine A. Frandsen and Lamont Hislop; U.S. Pat. No. 5,493,754, granted Feb. 27,1996 to Russell Gurstein and Edgar York; U.S. Pat. No. 5,815,869, granted Oct. 6, 1998 to John M. Hopkins; U.S. Pat. No. 5,839,155, granted Nov. 24, 1998 to Edward D. Berglund, Sung K. Cho and Lowell H. Schiebe; U.S. Pat. No. 6,115,862 granted Sep. 12, 2000 to Theodore R. Cooper, Allyson T. Toney and John B. McParlane; U.S. Pat. No. 6,348,227, granted Feb. 19, 2002, to Luis D. Caracciolo; U.S. Pat. No. 6,455,017, granted Sep. 24, 2002, to John R. Kasting, Dwayne H. Joines and John V. Winings; U.S. Pat. No. 6,458,398, granted Oct. 1, 2002 to Durand M. Smith, Dale S. Winger and Joshua N. Brown, and U.S. Pat. No. 6,638,364, granted Oct. 28, 2003 to Gene Harkins and John M. Hopkins. U.S. Pat. No. 6,454,017 discloses various uses of ozone as a sterilant. In this patent, it is stated that ozone cannot be combined with detergent or other cleaning agents since these are vulnerable to ozone attack. It is also stated that the ozone will destroy both its own effectiveness and that of the cleaning agent rather than attacking pathogens. U.S. Pat. No. 6,455,017 discloses directing a detergent cleaning solution, preferably under pressure, onto a surface to be cleaned. Then following the removal of the soils by the detergent an aqueous ozone rinse is applied to the surface. It is stated that the ozone rinse functions to sanitize the object being cleaned and remove residual detergent. The method of U.S. Pat. No. 6,455,017 involves first directing the cleaning solution onto the surface under pressure, and then rinsing the surface by directing a flow of the ozonated water onto the surface. U.S. Pat. No. 5,865,995, granted Feb. 2, 1999 to William R. Nelson, and U.S. Pat. No. 6,361,688, granted Mar. 26, 2002, also to William R. Nelson, disclose systems for producing “ozonated water”, also termed “ozone/water”. As well be described, the selected one of the systems is combined in a novel way in the system of the present invention. An object of the present invention is to deliver a high pressure cleaning water stream and an ozone/water stream substantially simultaneously to a surface to be cleaned and sanitized. The invention is basically characterized by delivering the high pressure water stream and the ozone/water stream closely adjacent to each other but without mixing. The high pressure water stream removes particles from the surface and the ozone/water stream sanitizes the surface almost simultaneously | <SOH> BRIEF SUMMARY OF THE INVENTION <EOH>The cleaning and sanitizing system of the present invention is basically characterized by a first discharge nozzle from which a stream of high pressure water is discharged and a second discharge nozzle from which a stream of ozone/water is discharged. The first and second nozzles are positioned adjacent to each other so that the water and ozone/water streams are contiguous but the ozone/water is not delivered into the high pressure water stream. The high pressure water stream is discharged at a pressure high enough that it will exert a cleaning force on a surface to be cleaned and would convert the ozone into oxygen if the ozone/water stream were to be delivered into the high pressure water stream. In preferred form, the pressure of the high water pressure stream is at least about 100 p.s.i. More preferably, the pressure of the high pressure water stream is between 100 p.s.i. and about 2000 p.s.i. The pressure of the ozone/water stream is smaller than the pressure of the high pressure water stream and is sufficiently small that the ozone is not converted into oxygen. According to one aspect of the invention, the ozone/water stream concentrically surrounds the high pressure water stream. According to another aspect of the invention, the high pressure water and the ozone/water are discharged as closely spaced substantially parallel streams. The nozzles for discharging the high pressure water and the ozone/water can be movable to the object that is to be cleaned. Or, the discharge nozzles can be fixed and the article to be cleaned can be moved relative to the nozzles. In an embodiment of the cleaning and sanitizing system of the present invention, a circulating flow path of ozone/water is provided. Along this path, one or more high pressure water discharge nozzles are provided. An ozone/water nozzle is associated with each high pressure water nozzle. The high pressure water stream may be used to “pump” or “aspirate” ozone/water from the circulating system. As ozone/water is removed from the system, new water is delivered to the ozone/water generator and additional ozone is added to the water in the generator. Other objects, advantages, and features of the invention will become apparent. From the description of the best mode set forth below, from the drawings, from the claims and from the principles that are embodied in the specific structure that are illustrated and described. | 20040109 | 20060808 | 20050714 | 99567.0 | 1 | KORNAKOV, MIKHAIL | CLEANING AND SANITIZING SYSTEM | SMALL | 0 | ACCEPTED | 2,004 |
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10,755,618 | ACCEPTED | Dialog component re-use in recognition systems | Controls are provided for a web server to generate client side markups that include recognition and/or audible prompting. The controls comprise elements of a dialog such as a question, answer, confirmation, command or statement. A module forms a dialog by making use of the information carried in the controls. The dialog follows a selected order of prompting and receiving input from a user as related to the order of the controls, and departs from the selected order as a function of responses from the user. The speech controls are adapted such that elements of the speech controls can be combined or re-used. | 1. A computer readable medium having instructions, which when executed on a computer generate client side markup for a client in a client/server system, the instructions comprising: a set of controls for defining a dialog, the controls comprising at least a control for generating markup related to audible prompting of a question and for generating markup related to a grammar for recognition, said control having means for referring to another control of the same type in order to duplicate at least a portion of the dialog of said another control; and a module, when executed on the client, creates a dialog as a function of the controls. 2. The computer readable medium of claim 1 wherein said control includes a prompt property for defining a prompt, an answer property defining the processing of responses by the user to the prompt, and wherein said means for referring to another control includes an imported answer property for identifying said another control. 3. The computer readable medium of claim 2 wherein said control is adapted to combine the processing of responses in the answer property with the processing of responses in the answer property of said another control identified in the imported answer property. 4. The computer readable medium of claim 3 wherein said control includes an extra answer property defining processing of responses by the user which were unsolicited in the prompt, and wherein said means for referring to another control includes an imported extra answer property for identifying said another control. 5. The computer readable medium of claim 4 wherein said control is adapted to combine the processing of responses in the extra answer property with the processing of responses in the extra answer property of said another control identified in the imported answer property. 6. The computer readable medium of claim 5 wherein said control [RL6] is adapted to combine the processing of responses in the extra answer property with the processing of responses in the extra answer property of said another control identified in the imported extra answer property. 7. The computer readable medium of claim 6 wherein said control is adapted to combine the processing of responses in the extra answer property with the processing of responses in the answer property of said another control identified in the imported extra answer property. 8. The computer readable medium of claim 1 and further comprising a second set of controls for generating markup related to visual rendering on a client, wherein at least one of the first-mentioned set of controls is associated with at least one of the controls of the second set of controls. 9. The computer readable medium of claim 8 wherein the first-mentioned set of controls includes means for maintaining a recognized result apart from the associated control of the second set of controls, said means for maintaining associating the recognized result with the control of the second set of controls. 10. The computer readable medium of claim 9 wherein said control includes a prompt property for defining a prompt, an answer property defining the processing of responses by the user to the prompt, and wherein said means for referring to another control includes an imported answer property for identifying said another control. 11. The computer readable medium of claim 10 wherein said control is adapted to combine the processing of responses in the answer property with the processing of responses in the answer property of said another control identified in the imported answer property. 12. The computer readable medium of claim 11 wherein said control includes an extra answer property defining processing of responses by the user which were unsolicited in the prompt, and wherein said means for referring to another control includes an imported extra answer property for identifying said another control. 13. The computer readable medium of claim 12 wherein said control is adapted to combine the processing of responses in the extra answer property with the processing of responses in the extra answer property of said another control identified in the imported answer property. 14. The computer readable medium of claim 14 wherein said control is adapted to combine the processing of responses in the extra answer property with the processing of responses in the extra answer property of said another control identified in the imported extra answer property. 15. The computer readable medium of claim 14 wherein said control is adapted to combine the processing of responses in the extra answer property with the processing of responses in the answer property of said another control identified in the imported extra answer property. 16. A computer-implemented method for generating client side markup for a client in a client/server system comprising: specifying an application from a set of controls for defining a dialog, the controls comprising at least a control for generating markup related to audible prompting of a question and for generating markup related to a grammar for recognition, said control having means for referring to another control of the same type in order to duplicate at least a portion of the dialog of said another control; and generating client side markup from the specified application. 17. The computer-implemented method of claim 16 wherein said control includes a prompt property for defining a prompt, an answer property defining the processing of responses by the user to the prompt, and wherein said means for referring to another control includes an imported answer property for identifying said another control. 18. The computer-implemented method of claim 17 wherein generating client side markup includes combining the processing of responses in the answer property with the processing of responses in the answer property of said another control identified in the imported answer property. 19. The computer-implemented method of claim 18 wherein said control includes an extra answer property defining processing of responses by the user which were unsolicited in the prompt, and wherein said means for referring to another control includes an imported extra answer property for identifying said another control. 20. The computer-implemented method of claim 19 wherein generating client side markup includes combining the processing of responses in the extra answer property with the processing of responses in the extra answer property of said another control identified in the imported answer property. 21. The computer-implemented method of claim 20 wherein generating client side markup includes combining the processing of responses in the extra answer property with the processing of responses in the extra answer property of said another control identified in the imported extra answer property. 22. The computer-implemented method of claim 21 wherein generating client side markup includes combining the processing of responses in the extra answer property with the processing of responses in the answer property of said another control identified in the imported extra answer property. 23. The computer-implemented method of claim 18 wherein combining the processing of responses in the answer property with the processing of responses in the answer property of said another control identified in the imported answer property includes associating a grammar for the processing of responses in the answer property of said another control identified in the imported answer property, said grammar being differentiated from a grammar for processing other responses associated with the answer property. 24. The computer-implemented method of claim 23 wherein associating a grammar for the processing of responses in the answer property of said another control identified in the imported answer property includes using a unique identifier for each of the answers[RL7]. 25. The computer-implemented method of claim 20 wherein combining the processing of responses in the extra answer property with the processing of responses in the extra answer property of said another control identified in the imported extra answer property includes associating a grammar for the processing of responses in the extra answer property of said another control identified in the imported extra answer property, said grammar being differentiated from a grammar for processing other responses associated with the extra answer property. 26. The computer-implemented method of claim 25 wherein associating a grammar for the processing of responses in the extra answer property of said another control identified in the imported extra answer property includes using a unique identifier for each of the extra answers[RL8]. 27. The computer-implemented method of claim 16 wherein specifying an application includes specifying re-use of a grammar by reference to a control[RL9]. 28. The computer-implemented method of claim 27 wherein specifying an application includes specifying re-use of only a portion of a grammar by reference to a control. 29. The computer-implemented method of claim 28 wherein specifying an application includes specifying re-use of only a portion of a grammar by reference to a control, said portion not having carrier phrases. | CROSS-REFERENCE TO RELATED APPLICATIONS The present application relates to U.S. patent application entitled APPLICATION ABSTRACTION WITH DIALOG PURPOSE having Ser. No. 10/087,608, filed Oct. 21, 2001, and published as U.S. 2003/0130854; U.S. patent application entitled APPLICATION ABSTRACTION WITH DIALOG PURPOSE having Ser. No. 10/426,053, filed Apr. 28, 2003; and U.S. patent application entitled APPLICATION CONTROLS FOR SPEECH ENABLED RECOGNITION having Ser. No. 10/426,027, filed Apr. 28, 2003, the contents of which are hereby incorporated be reference in their entirety. BACKGROUND OF THE INVENTION The present invention generally relates to encoding computers to perform a specific application. More particularly, the present invention relates to controls for defining an application to perform recognition and/or audible prompting such as a server that generates client side markup enabled with recognition and/or audible prompting. Small computing devices such as personal information managers (PIM), devices and portable phones are used with ever increasing frequency by people in their day-to-day activities. With the increase in processing power now available for microprocessors used to run these devices, the functionality of these devices are increasing, and in some cases, merging. For instance, many portable phones now can be used to access and browse the Internet as well as can be used to store personal information such as addresses, phone numbers and the like. In view that these computing devices are being used for browsing the Internet, or are used in other server/client architectures, it is therefore necessary to enter information into the computing device. Unfortunately, due to the desire to keep these devices as small as possible in order that they are easily carried, conventional keyboards having all the letters of the alphabet as isolated buttons are usually not possible due to the limited surface area available on the housings of the computing devices. To address this problem, there has been increased interest and adoption of using voice or speech to provide and access such information, particularly over a wide area network such as the Internet. Published U.S. patent application, U.S. 2003/0130854, entitled APPLICATION ABSTRACTION WITH DIALOG PURPOSE and U.S. patent application entitled APPLICATION ABSTRACTION WITH DIALOG PURPOSE having Ser. No. 10/426,053, filed Apr. 28, 2003 describe a method and system defining controls for a web server to generate client side markups that include recognition and/or audible prompting. Each of the controls perform a role in the dialog. For instance, controls can include prompt object used to generate corresponding markup for the client device to present information to the user, or generate markups for the client device to ask a question. An answer control or object generates markup for the client device so that a grammar used for recognition is associated with an input field related to a question that has been asked. If it is unclear whether or not a recognized result is correct, a confirmation mechanism can be activated and generate markup to confirm a recognized result. A command control generates markup that allows the user to provide commands, which are other than the expected answers to a specific question, and thus, allows the user to navigate through the web server application, for example. An application control provides a means to wrap common speech scenarios in one control. A module, when executed such as on a client, creates a dialog to solicit and provide information as a function of the controls. The module can use a control mechanism that identifies an order for the dialog, for example, an order for asking questions. The controls include activation logic that may activate other controls based on the answer given by the user. In many cases, the controls specify and allow the user to provide extra answers, which are commonly answers to questions yet to be asked, and thereby, cause the system to skip such questions since such answers have already been provided. This type of dialog is referred to as “mixed-initiative” since the system and the user have some control of dialog flow. The controls, when executed on a computer, generate client side markup for a client in a client/server system. A first set of visual controls have attributes for visual rendering on the client device, while a second set of controls have attributes related to at least one of recognition and audibly prompting. The application control is used to perform a selected task on the client device. The application control has properties for outputting controls of the second set to perform the selected task and associating the outputted controls with the first set of controls. In short, an application control, allows the application author to rapidly develop an application by using application controls rather than manually coding all the necessary syntax with the first and second set of controls to perform a selected task. The tasks can include obtaining information, e.g. numbers, characters, dates etc., or navigating a table of information. The application that is developed may include various built-in prompts, grammars and dialog flow or generate these features automatically. Use of the application controls saves time and thereby cost in developing the application. However, although the application controls provide helpful building block mechanisms for implementing a recognition based application, the controls are not particularly well suited for a mixed-initiative dialogue where the user provides information that eventually will be required, but does so before such questions are asked. Improved methods or techniques to better handle mixed-initiative dialogue in a convenient manner would thus be helpful. SUMMARY OF THE INVENTION Controls are provided for a web server to generate client side markups that include recognition and/or audible prompting. The controls comprise elements of a dialog such as a question, answer, confirmation, command or statement. A module forms a dialog by making use of the information carried in the controls. Each of the controls perform a role in the dialog. For instance, controls can include prompt object used to generate corresponding markup for the client device to present information to the user, or generate markups for the client device to ask a question. An answer control or object generates markup for the client device so that a grammar used for recognition is associated with an input field related to a question that has been asked. If it is unclear whether or not a recognized result is correct, a confirmation mechanism can be activated and generate markup to confirm a recognized result. A module, when executed such as on a client, creates a dialog to solicit and provide information as a function of the controls. An aspect of the present invention is to allow the speech controls to refer to other speech controls such that elements can be combined or re-used. This allows more rapid design of the application in that common need not be repeated. In addition, the resulting application is better equipped to handle mixed-initiative dialogues. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a first embodiment of a computing device operating environment. FIG. 2 is a block diagram of the computing device of FIG. 1. FIG. 3 is a block diagram of a general purpose computer. FIG. 4 is a block diagram of an architecture for a client/server system. FIG. 5 is a display for obtaining credit card information. FIG. 6 is a block diagram illustrating a first approach for providing recognition and audible prompting in client side markups. FIG. 7 is a block diagram illustrating a second approach for providing recognition and audible prompting in client side markups. FIG. 8 is a block diagram illustrating a third approach for providing recognition and audible prompting in client side markups. FIG. 9 is a block diagram illustrating companion controls. FIG. 10 is a detailed block diagram illustrating companion controls of a first embodiment. FIG. 11 is a block diagram illustrating companion controls of a second embodiment. FIG. 12 is a block diagram illustrating speech controls inheritance for the second embodiment. FIG. 13 is a pictorial representation of combining answers in a speech control. DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS Before describing architecture of web based recognition and methods for implementing the same, it may be useful to describe generally computing devices that can function in the architecture. Referring now to FIG. 1, an exemplary form of a data management device (PIM, PDA or the like) is illustrated at 30. However, it is contemplated that the present invention can also be practiced using other computing devices discussed below, and in particular, those computing devices having limited surface areas for input buttons or the like. For example, phones and/or data management devices will also benefit from the present invention. Such devices will have an enhanced utility compared to existing portable personal information management devices and other portable electronic devices, and the functions and compact size of such devices will more likely encourage the user to carry the device at all times. Accordingly, it is not intended that the scope of the architecture herein described be limited by the disclosure of an exemplary data management or PIM device, phone or computer herein illustrated. An exemplary form of a data management mobile device 30 is illustrated in FIG. 1. The mobile device 30 includes a housing 32 and has an user interface including a display 34, which uses a contact sensitive display screen in conjunction with a stylus 33. The stylus 33 is used to press or contact the display 34 at designated coordinates to select a field, to selectively move a starting position of a cursor, or to otherwise provide command information such as through gestures or handwriting. Alternatively, or in addition, one or more buttons 35 can be included on the device 30 for navigation. In addition, other input mechanisms such as rotatable wheels, rollers or the like can also be provided. However, it should be noted that the invention is not intended to be limited by these forms of input mechanisms. For instance, another form of input can include a visual input such as through computer vision. Referring now to FIG. 2, a block diagram illustrates the functional components comprising the mobile device 30. A central processing unit (CPU) 50 implements the software control functions. CPU 50 is coupled to display 34 so that text and graphic icons generated in accordance with the controlling software appear on the display 34. A speaker 43 can be coupled to CPU 50 typically with a digital-to-analog converter 59 to provide an audible output. Data that is downloaded or entered by the user into the mobile device 30 is stored in a non-volatile read/write random access memory store 54 bi-directionally coupled to the CPU 50. Random access memory (RAM) 54 provides volatile storage for instructions that are executed by CPU 50, and storage for temporary data, such as register values. Default values for configuration options and other variables are stored in a read only memory (ROM) 58. ROM 58 can also be used to store the operating system software for the device that controls the basic functionality of the mobile 30 and other operating system kernel functions (e.g., the loading of software components into RAM 54). RAM 54 also serves as a storage for the code in the manner analogous to the function of a hard drive on a PC that is used to store application programs. It should be noted that although non-volatile memory is used for storing the code, it alternatively can be stored in volatile memory that is not used for execution of the code. Wireless signals can be transmitted/received by the mobile device through a wireless transceiver 52, which is coupled to CPU 50. An optional communication interface 60 can also be provided for downloading data directly from a computer (e.g., desktop computer), or from a wired network, if desired. Accordingly, interface 60 can comprise various forms of communication devices, for example, an infrared link, modem, a network card, or the like. Mobile device 30 includes a microphone 29, and analog-to-digital (A/D) converter 37, and an optional recognition program (speech, DTMF, handwriting, gesture or computer vision) stored in store 54. By way of example, in response to audible information, instructions or commands from a user of device 30, microphone 29 provides speech signals, which are digitized by A/D converter 37. The speech recognition program can perform normalization and/or feature extraction functions on the digitized speech signals to obtain intermediate speech recognition results. Using wireless transceiver 52 or communication interface 60, speech data is transmitted to a remote recognition server 204 discussed below and illustrated in the architecture of FIG. 4. Recognition results are then returned to mobile device 30 for rendering (e.g. visual and/or audible) thereon, and eventual transmission to a web server 202 (FIG. 5), wherein the web server 202 and mobile device 30 operate in a client/server relationship. Similar processing can be used for other forms of input. For example, handwriting input can be digitized with or without pre-processing on device 30. Like the speech data, this form of input can be transmitted to the recognition server 204 for recognition wherein the recognition results are returned to at least one of the device 30 and/or web server 202. Likewise, DTMF data, gesture data and visual data can be processed similarly. Depending on the form of input, device 30 (and the other forms of clients discussed below) would include necessary hardware such as a camera for visual input. In addition to the portable or mobile computing devices described above, it should also be understood that the present invention can be used with numerous other computing devices such as a general desktop computer. For instance, the present invention will allow a user with limited physical abilities to input or enter text into a computer or other computing device when other conventional input devices, such as a full alpha-numeric keyboard, are too difficult to operate. The invention is also operational with numerous other general purpose or special purpose computing systems, environments or configurations. Examples of well known computing systems, environments, and/or configurations that may be suitable for use with the invention include, but are not limited to, wireless or cellular telephones, regular telephones (without any screen), personal computers, server computers, hand-held or laptop devices, multiprocessor systems, microprocessor-based systems, set top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, distributed computing environments that include any of the above systems or devices, and the like. The following is a brief description of a general purpose computer 120 illustrated in FIG. 3. However, the computer 120 is again only one example of a suitable computing environment and is not intended to suggest any limitation as to the scope of use or functionality of the invention. Neither should the computer 120 be interpreted as having any dependency or requirement relating to any one or combination of components illustrated therein. The invention may be described in the general context of computer-executable instructions, such as program modules, being executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. The invention may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote computer storage media including memory storage devices. Tasks performed by the programs and modules are described below and with the aid of figures. Those skilled in the art can implement the description and figures as processor executable instructions, which can be written on any form of a computer readable medium. With reference to FIG. 3, components of computer 120 may include, but are not limited to, a processing unit 140, a system memory 150, and a system bus 141 that couples various system components including the system memory to the processing unit 140. The system bus 141 may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. By way of example, and not limitation, such architectures include Industry Standard Architecture (ISA) bus, Universal Serial Bus (USB), Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect (PCI) bus also known as Mezzanine bus. Computer 120 typically includes a variety of computer readable mediums. Computer readable mediums can be any available media that can be accessed by computer 120 and includes both volatile and nonvolatile media, removable and non-removable media. By way of example, and not limitation, computer readable mediums may comprise computer storage media and communication media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by computer 120. Communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. The term “modulated data signal” means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media includes wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, FR, infrared and other wireless media. Combinations of any of the above should also be included within the scope of computer readable media. The system memory 150 includes computer storage media in the form of volatile and/or nonvolatile memory such as read only memory (ROM) 151 and random access memory (RAM) 152. A basic input/output system 153 (BIOS), containing the basic routines that help to transfer information between elements within computer 120, such as during start-up, is typically stored in ROM 151. RAM 152 typically contains data and/or program modules that are immediately accessible to and/or presently being operated on by processing unit 140. By way of example, and not limitation, FIG. 3 illustrates operating system 54, application programs 155, other program modules 156, and program data 157. The computer 120 may also include other removable/non-removable volatile/nonvolatile computer storage media. By way of example only, FIG. 3 illustrates a hard disk drive 161 that reads from or writes to non-removable, nonvolatile magnetic media, a magnetic disk drive 171 that reads from or writes to a removable, nonvolatile magnetic disk 172, and an optical disk drive 175 that reads from or writes to a removable, nonvolatile optical disk 176 such as a CD ROM or other optical media. Other removable/non-removable, volatile/nonvolatile computer storage media that can be used in the exemplary operating environment include, but are not limited to, magnetic tape cassettes, flash memory cards, digital versatile disks, digital video tape, solid state RAM, solid state ROM, and the like. The hard disk drive 161 is typically connected to the system bus 141 through a non-removable memory interface such as interface 160, and magnetic disk drive 171 and optical disk drive 175 are typically connected to the system bus 141 by a removable memory interface, such as interface 170. The drives and their associated computer storage media discussed above and illustrated in FIG. 3, provide storage of computer readable instructions, data structures, program modules and other data for the computer 120. In FIG. 3, for example, hard disk drive 161 is illustrated as storing operating system 164, application programs 165, other program modules 166, and program data 167. Note that these components can either be the same as or different from operating system 154, application programs 155, other program modules 156, and program data 157. Operating system 164, application programs 165, other program modules 166, and program data 167 are given different numbers here to illustrate that, at a minimum, they are different copies. A user may enter commands and information into the computer 120 through input devices such as a keyboard 182, a microphone 183, and a pointing device 181, such as a mouse, trackball or touch pad. Other input devices (not shown) may include a joystick, game pad, satellite dish, scanner, or the like. These and other input devices are often connected to the processing unit 140 through a user input interface 180 that is coupled to the system bus, but may be connected by other interface and bus structures, such as a parallel port, game port or a universal serial bus (USB). A monitor 184 or other type of display device is also connected to the system bus 141 via an interface, such as a video interface 185. In addition to the monitor, computers may also include other peripheral output devices such as speakers 187 and printer 186, which may be connected through an output peripheral interface 188. The computer 120 may operate in a networked environment using logical connections to one or more remote computers, such as a remote computer 194. The remote computer 194 may be a personal computer, a hand-held device, a server, a router, a network PC, a peer device or other common network node, and typically includes many or all of the elements described above relative to the computer 120. The logical connections depicted in FIG. 3 include a local area network (LAN) 191 and a wide area network (WAN) 193, but may also include other networks. Such networking environments are commonplace in offices, enterprise-wide computer networks, intranets and the Internet. When used in a LAN networking environment, the computer 120 is connected to the LAN 191 through a network interface or adapter 190. When used in a WAN networking environment, the computer 120 typically includes a modem 192 or other means for establishing communications over the WAN 193, such as the Internet. The modem 192, which may be internal or external, may be connected to the system bus 141 via the user input interface 180, or other appropriate mechanism. In a networked environment, program modules depicted relative to the computer 120, or portions thereof, may be stored in the remote memory storage device. By way of example, and not limitation, FIG. 3 illustrates remote application programs 195 as residing on remote computer 194. It will be appreciated that the network connections shown are exemplary and other means of establishing a communications link between the computers may be used. Exemplary Architecture FIG. 4 illustrates architecture 200 for web based recognition as can be used with the present invention. Generally, information stored in a web server 202 can be accessed through mobile device 30 (which herein also represents other forms of computing devices having a display screen, a microphone, a camera, a touch sensitive panel, etc., as required based on the form of input), or through phone 80 wherein information is requested audibly or through tones generated by phone 80 in response to keys depressed and wherein information from web server 202 is provided only audibly back to the user. In this exemplary embodiment, architecture 200 is unified in that whether information is obtained through device 30 or phone 80 using speech recognition, a single recognition server 204 can support either mode of operation. In addition, architecture 200 operates using an extension of well-known markup languages (e.g. HTML, XHTML, cHTML, XML, WML, and the like). Thus, information stored on web server 202 can also be accessed using well-known GUI methods found in these markup languages. By using an extension of well-known markup languages, authoring on the web server 202 is easier, and legacy applications currently existing can be also easily modified to include voice or other forms of recognition. Generally, device 30 executes HTML+ scripts, or the like, provided by web server 202. When voice recognition is required, by way of example, speech data, which can be digitized audio signals or speech features wherein the audio signals have been preprocessed by device 30 as discussed above, are provided to recognition server 204 with an indication of a grammar or language model to use during speech recognition. The implementation of the recognition server 204 can take many forms, one of which is illustrated, but generally includes a recognizer 211. The results of recognition are provided back to device 30 for local rendering if desired or appropriate. Upon compilation of information through recognition and any graphical user interface if used, device 30 sends the information to web server 202 for further processing and receipt of further HTML scripts, if necessary. As illustrated in FIG. 4, device 30, web server 202 and recognition server 204 are commonly connected, and separately addressable, through a network 205, herein a wide area network such as the Internet. It therefore is not necessary that any of these devices be physically located adjacent to each other. In particular, it is not necessary that web server 202 includes recognition server 204. In this manner, authoring at web server 202 can be focused on the application to which it is intended without the authors needing to know the intricacies of recognition server 204. Rather, recognition server 204 can be independently designed and connected to the network 205, and thereby, be updated and improved without further changes required at web server 202. As discussed below, web server 202 can also include an authoring mechanism that can dynamically generate client-side markups and scripts. In a further embodiment, the web server 202, recognition server 204 and client 30 may be combined depending on the capabilities of the implementing machines. For instance, if the client comprises a general purpose computer, e.g. a personal computer, the client may include the recognition server 204. Likewise, if desired, the web server 202 and recognition server 204 can be incorporated into a single machine. Access to web server 202 through phone 80 includes connection of phone 80 to a wired or wireless telephone network 208, that in turn, connects phone 80 to a third party gateway 210. Gateway 210 connects phone 80 to a telephony voice browser 212. Telephone voice browser 212 includes a media server 214 that provides a telephony interface and a voice browser 216. Like device 30, telephony voice browser 212 receives HTML scripts or the like from web server 202. In one embodiment, the HTML scripts are of the form similar to HTML scripts provided to device 30. In this manner, web server 202 need not support device 30 and phone 80 separately, or even support standard GUI clients separately. Rather, a common markup language can be used. In addition, like device 30, voice recognition from audible signals transmitted by phone 80 are provided from voice browser 216 to recognition server 204, either through the network 205, or through a dedicated line 207, for example, using TCP/IP. Web server 202, recognition server 204 and telephone voice browser 212 can be embodied in any suitable computing environment such as the general purpose desktop computer illustrated in FIG. 3. However, it should be noted that if DTMF recognition is employed, this form of recognition would generally be performed at the media server 214, rather than at the recognition server 204. In other words, the DTMF grammar would be used by the media server 214. Referring back to FIG. 4, web server 202 can include a server side plug-in authoring tool or module 209 (e.g. ASP, ASP+, ASP.Net by Microsoft Corporation, JSP, Javabeans, or the like). Server side plug-in module 209 can dynamically generate client-side markups and even a specific form of markup for the type of client accessing the web server 202. The client information can be provided to the web server 202 upon initial establishment of the client/server relationship, or the web server 202 can include modules or routines to detect the capabilities of the client device. In this manner, server side plug-in module 209 can generate a client side markup for each of the voice recognition scenarios, i.e. voice only through phone 80 or multimodal for device 30. By using a consistent client side model, application authoring for many different clients is significantly easier. In addition to dynamically generating client side markups, high-level dialog modules, discussed below, can be implemented as a server-side control stored in store 211 for use by developers in application authoring. In general, the high-level dialog modules 211 would generate dynamically client-side markup and script in both voice-only and multimodal scenarios based on parameters specified by developers. The high-level dialog modules 211 can include parameters to generate client-side markups to fit the developers' needs. Exemplary Client Side Extensions Before describing further aspect of the present invention, it may be helpful to first discuss an exemplary form of extensions to the markup language for use in web based recognition. As indicated above, the markup languages such as HTML, XHTML cHTML, XML, WML or any other SGML-derived markup, which are used for interaction between the web server 202 and the client device 30 and phone 80, are extended to include controls and/or objects that provide recognition in a client/server architecture. Generally, controls and/or objects can include one or more of the following functions: recognizer controls and/or objects for recognizer configuration, recognizer execution and/or post-processing; synthesizer controls and/or objects for synthesizer configuration and prompt playing; grammar controls and/or objects for specifying input grammar resources; and/or binding controls and/or objects for processing recognition results. The extensions are designed to be a lightweight markup layer, which adds the power of an audible, visual, handwriting, etc. interface to existing markup languages. As such, the extensions can remain independent of: the high-level page in which they are contained, e.g. HTML; the low-level formats which the extensions used to refer to linguistic resources, e.g. the text-to-speech and grammar formats; and the individual properties of the recognition and speech synthesis platforms used in the recognition server 204. It should be noted, a markup language extension such as speech application language tags (SALT) can be used. SALT is a developing standard for enabling access to information, applications and web services from personal computers, telephones, tablet PCs and wireless mobile devices, for example. SALT extends existing markup languages such as HTML, XHTML and XML. An example of the SALT specification can be found in Published U.S. patent application, U.S. 2003/0130854, entitled APPLICATION ABSTRACTION WITH DIALOG PURPOSE, which is herein incorporated by reference in its entirety. The SALT specification may be found online at http://www.SALTforum.org. Further details regarding the extensions are not necessary for understanding the present invention. Although speech recognition will be discussed below, it should be understood that the techniques, tags and server side controls described hereinafter can be similarly applied in handwriting recognition, gesture recognition and image recognition. At this point though, a particular mode of entry should be discussed. In particular, use of speech recognition in conjunction with at least a display and, in a further embodiment, a pointing device as well which enables the coordination of multiple modes of input, e.g. to indicate the fields for data entry, is particularly useful. Specifically, in this mode of data entry, the user is generally able to coordinate the actions of the pointing device with the speech input, so for example the user is under control of when to select a field and provide corresponding information relevant to the field. For instance, a credit card submission graphical user interface (GUI) is illustrated in FIG. 5, a user could first decide to enter the credit card number in field 252 and then enter the type of credit card in field 250 followed by the expiration date in field 254. Likewise, the user could return back to field 252 and correct an errant entry, if desired. When combined with speech recognition, an easy and natural form of navigation is provided. As used herein, this form of entry using both a screen display allowing free form actions of the pointing device on the screen, e.g. the selection of fields and recognition is called “multimodal”. When rendered using the phone 80 in a voice-only application, the user would be prompted to provide the information illustrated in FIG. 5. Generation of Client Side Markups As indicated above, server side plug-in module 209 outputs client side markups when a request has been made from the client device 30 or telephony voice browser 212. Although possibly described below with respect to the client device, it should be understood that the telephony voice browser 212 is inferred as an example device for voice-only applications. In short, the server side plug-in module 209 allows the website, and thus, the application and services provided by the application to be defined or constructed. The instructions in the server side plug-in module 209 are made of a complied code. The code is run when a web request reaches the web server 202. The server side plug-in module 209 then outputs a new client side markup page that is sent to the client device 30 or telephony voice browser 212. As is well known, this process is commonly referred to as rendering. The server side plug-in module 209 operates on “controls” that abstract and encapsulate the markup language, and thus, the code of the client side markup page. Such controls that abstract and encapsulate the markup language and operate on the webserver 202 include or are equivalent to “Servlets” or “Server-side plug ins” to name a few. As is known, server side plug-in modules of the prior art can generate client side markup for visual rendering and interaction with the client device 30. Three different approaches are provided herein for extending the server side plug-in module 209 to include recognition and audible prompting extensions such as the exemplary client side extensions discussed above. In a first approach illustrated schematically in FIG. 6, the current, visual, server side controls (which include parameters for visual display such as location for rendering, font, foreground color, background color, etc.) are extended to include parameters or attributes for recognition and audibly prompting for related recognition. Using speech recognition and associated audible prompting by way of example, the attributes generally pertain to audible prompting parameters such as whether the prompt comprises inline text for text-to-speech conversion, playing of a prerecorded audio file (e.g. a wave file), the location of the data (text for text-to-speech conversion or a prerecorded audio file) for audible rendering, etc. For recognition, the parameters or attributes can include the location of the grammar to be used during recognition, confidence level thresholds, etc. Since the server side plug-in module 209 generates client side markup, the parameters and attributes for the controls for the server side plug-in module 209 relate to the extensions provided in the client side markup for recognition and/or audible prompting. The controls indicated at 300A in FIG. 6 are controls, which are well-known in website application development or authoring tools such as ASP, ASP+, ASP.Net, JSP, Javabeans, or the like. Such controls are commonly formed in a library and used by controls 302 to perform a particular visual task. Library 300A includes methods for generating the desired client markup, event handlers, etc. Examples of visual controls 302 include a “Label” control that provides a selected text label on a visual display such as the label “Credit Card Submission” 304 in FIG. 5. Another example of a higher level visual control 302 is a “Textbox”, which allows data to be entered in a data field such as is indicated at 250 in FIG. 5. The existing visual controls 302 are also well-known. In the first approach for extending server side plug-in module controls to include recognition and/or audible prompting, each of the visual controls 302 would include further parameters or attributes related to recognition or audible prompting. In the case of the “label” control, which otherwise provides selected text on a visual display, further attributes may include whether an audio data file will be rendered or text-to-speech conversion will be employed as well as the location of this data file. A library 300B, similar to library 300A, includes further markup information for performing recognition and/or audible prompting. Each of the visual controls 302 is coded so as to provide this information to the controls 300B as appropriate to perform the particular task related to recognition or audible prompting. As another example, the “Textbox” control, which generates an input field on a visual display and allows the user of the client device 30 to enter information, would also include appropriate recognition or audible prompting parameters or attributes such as the grammar to be used for recognition. It should be noted that the recognition or audible prompting parameters are optional and need not be used if recognition or audible prompting is not otherwise desired. In general, if a control at level 302 includes parameters that pertain to visual aspects, the control will access and use the library 300A. Likewise, if the control includes parameters pertaining to recognition and/or audible prompting the control will access or use the library 300B. It should be noted that libraries 300A and 300B have been illustrated separately in order to emphasize the additional information present in library 300B and that a single library having the information of libraries 300A and 300B can be implemented. In this approach, each of the current or prior art visual controls 302 are extended to include appropriate recognition/audible prompting attributes. The controls 302 can be formed in a library. The server side plug-in module 209 accesses the library for markup information. Execution of the controls generates a client side markup page, or a portion thereof, with the provided parameters. In a second approach illustrated in FIG. 7, new visual, recognition/audible prompting controls 304 are provided such that the controls 304 are a subclass relative to visual controls 302, wherein recognition/audible prompting functionality or markup information is provided at controls 304. In other words, a new set of controls 304 are provided for recognition/audible prompting and include appropriate parameters or attributes to perform the desired recognition or an audible prompting related to a recognition task on the client device 30. The controls 304 use the existing visual controls 302 to the extent that visual information is rendered or obtained through a display. For instance, a control “SpeechLabel” at level 304 uses the “Label” control at level 302 to provide an audible rendering and/or visual text rendering. Likewise, a “SpeechTextbox” control would associate a grammar and related recognition resources and processing with an input field. Like the first approach, the attributes for controls 304 include where the grammar is located for recognition, the inline text for text-to-speech conversion, or the location of a prerecorded audio data file that will be rendered directly or a text file through text-to-speech conversion. The second approach is advantageous in that interactions of the recognition controls 304 with the visual controls 302 are through parameters or attributes, and thus, changes in the visual controls 302 may not require any changes in the recognition controls 304 provided the parameters or attributes interfacing between the controls 304 and 302 are still appropriate. However, with the creation of further visual controls 302, a corresponding recognition/audible prompting control at level 304 may also have to be written. A third approach is illustrated in FIG. 8. Generally, controls 306 of the third approach are separate from the visual controls 302, but are associated selectively therewith as discussed below. In this manner, the controls 306 do not directly build upon the visual controls 302, but rather provide recognition/audible prompting enablement without having to rewrite the visual controls 302. The controls 306, like the controls 302, use a library 300. In this embodiment, library 300 includes both visual and recognition/audible prompting markup information and as such is a combination of libraries 300A and 300B of FIG. 6. There are significant advantages to this third approach. Firstly, the visual controls 302 do not need to be changed in content. Secondly, the controls 306 can form a single module which is consistent and does not need to change according to the nature of the speech-enabled control 302. Thirdly, the process of speech enablement, that is, the explicit association of the controls 306 with the visual controls 302 is fully under the developer's control at design time, since it is an explicit and selective process. This also makes it possible for the markup language of the visual controls to receive input values from multiple sources such as through recognition provided by the markup language generated by controls 306, or through a conventional input device such as a keyboard. In short, the controls 306 can be added to an existing application authoring page of a visual authoring page of the server side plug-in module 209. The controls 306 provide a new modality of interaction (i.e. recognition and/or audible prompting) for the user of the client device 30, while reusing the visual controls' application logic and visual input/output capabilities. In view that the controls 306 can be associated with the visual controls 302 whereat the application logic can be coded, controls 306 may be hereinafter referred to as “companion controls 306” and the visual controls 302 be referred to as “primary controls 302”. It should be noted that these references are provided for purposes of distinguishing controls 302 and 306 and are not intended to be limiting. For instance, the companion controls 306 could be used to develop or author a website that does not include visual renderings such as a voice-only website. In such a case, certain application logic could be embodied in the companion control logic. A first exemplary set of companion controls 306 are further illustrated in FIG. 9. The set of companion controls 306 can be grouped as output controls 308 and input controls 310. Output controls 308 provide “prompting” client side markups, which typically involves the playing of a prerecorded audio file, or text for text-to-speech conversion, the data included in the markup directly or referenced via a URL. Although a single output control can be defined with parameters to handle all audible prompting, in the exemplary embodiment, the forms or types of audible prompting in a human dialog are formed as separate controls. In particular, the output controls 308 can include a “Question” control 308A, a “Confirmation” control 308B and a “Statement” control 308C, which will be discussed in detail below. Likewise, the input controls 310 can also form or follow human dialog and include a “Answer” control 310A and a “Command” control 310B. The input controls 310 are discussed below, but generally the input controls 310 associate a grammar with expected or possible input from the user of the client device 30. Although the question control 308A, confirmation control 308B, statement control 308C, answer control 310A, command control 310B, other controls as well as the general structure of these controls, the parameters and event handlers, are specifically discussed with respect to use as companion controls 306, it should be understood that these controls, the general structure, parameters and event handlers can be adapted to provide recognition and/or audible prompting in the other two approaches discussed above with respect to FIGS. 6 and 7. For instance, the parameter “ClientToSpeechEnable”, which comprises one exemplary mechanism to form the association between a companion control and a visual control, would not be needed when embodied in the approaches of FIGS. 6 and 7. In a multimodal application, at least one of the output controls 308 or one of the input controls 310 is associated with a primary or visual control 302. In the embodiment illustrated, the output controls 308 and input controls 310 are arranged or organized under a “Question/Answer” (hereinafter also “QA”) control 320. QA control 320 is executed on the web server 202, which means it is defined on the application development web page held on the web server using the server-side markup formalism (ASP, JSP or the like), but is output as a different form of markup to the client device 30 or telephony voice browser 212. Although illustrated in FIG. 9 where the QA control appears to be formed of all of the output controls 308 and the input controls 310, it should be understood that these are merely options wherein one or more may be included for a QA control. At this point it may be helpful to explain use of the controls 308 and 310 in terms of application scenarios. Referring to FIG. 10 and in a voice-only application QA control 320 could comprise a single question control 308A and an answer control 310A. The question control 308A contains one or more prompt objects or controls 322, while the answer control 310A can define a grammar through grammar object or control 324 for recognition of the input data and related processing on that input. Line 326 represents the association of the QA control 320 with the corresponding primary control 302, if used. In a multimodal scenario, where the user of the client device 30 may touch on the visual textbox, for example with a “TapEvent”, an audible prompt may not be necessary. For example, for a primary control comprising a textbox having visual text forming an indication of what the user of client device should enter in the corresponding field, a corresponding QA control 320 may or may not have a corresponding prompt such as an audio playback or a text-to-speech conversion, but would have a grammar corresponding to the expected value for recognition, and event handlers 328 to process the input, or process other recognizer events such as no speech detected, speech not recognized, or events fired on timeouts (as illustrated in “Eventing” below). In general, the QA control through the output controls 308 and input controls 310 and additional logic can perform one or more of the following: provide output audible prompting, collect input data, perform confidence validation of the input result, allow additional types of input such as “help” commands, or commands that allow the user of the client device to navigate to other selected areas of the website, allow confirmation of input data and control of dialog flow at the website, to name a few. In short, the QA control 320 contains all the controls related to a specific topic. In this manner, a dialog is created through use of the controls with respect to the topic in order to inform to obtain information, to confirm validity, or to repair a dialog or change the topic of conversation. In one method of development, the application developer can define the visual layout of the application using the visual controls 302. The application developer can then define the spoken interface of the application using companion controls 306 (embodied as QA control 320, or output controls 308 and input control 310). As illustrated in FIGS. 9 and 10, each of the companion controls 306 are then linked or otherwise associated with the corresponding primary or visual control 302 to provide recognition and audible prompting. Of course if desired, the application developer can define or encode the application by switching between visual controls 302 and companion controls 306, forming the links therebetween, until the application is completely defined or encoded. At this point, it may be helpful to provide a short description of each of the output controls 308 and input controls 310. Detailed descriptions are provided below for this embodiment in Appendix A. Questions, Answers and Commands Generally, as indicated above, the question controls 308A and answer controls 310A in a QA control 320 hold the prompt and grammar resources relevant to the primary control 302, and related binding (associating recognition results with input fields of the client-side markup page) and processing logic. The presence, or not, of question controls 308A and answer controls 310A determines whether speech output or recognition input is enabled on activation. Command controls 310B and user initiative answers are activated by specification of the Scope property on the answer controls 310A and command controls 310B. In simple voice-only applications, a QA control 320 will typically hold one question control or object 308A and one answer control or object 310A. Although not shown in the example below, command controls 310B may also be specified, e.g. Help, Repeat, Cancel, etc., to enable user input which does not directly relate to the answering of a particular question. A typical ‘regular’ QA control for voice-only dialog is as follows: <Speech:QA id=”QA_WhichOne” ControlsToSpeechEnable=”textBox1” runat=”server” > <Question > <prompt> Which one do you want? </prompt> </Question> <Answer > <grammar src=”whichOne.gram” /> </Answer> </Speech:QA> (The examples provided herein are written in the ASP.Net framework by example only and should not be considered as limiting the present invention.) In this example, the QA control can be identified by its “id”, while the association of the QA control with the desired primary or visual control is obtained through the parameter “ControlsToSpeechEnable”, which identifies one or more primary controls by their respective identifiers. If desired, other well-known techniques can be used to form the association. For instance, direct, implicit associations are available through the first and second approaches described above, or separate tables can be created used to maintain the associations. The parameter “runat” instructs the web server that this code should be executed at the webserver 202 to generate the correct markup. A QA control might also hold only a statement control 308C, in which case it is a prompt-only control without active grammars (e.g. for a welcome prompt). Similarly a QA control might hold only an answer control 310A, in which case it may be a multimodal control, whose answer control 310A activates its grammars directly as the result of an event from the GUI, or a scoped mechanism (discussed below) for user initiative. It should also be noted that a QA control 320 may also hold multiple output controls 308 and input controls 310 such as multiple question controls 308A and multiple answers controls 310A. This allows an author to describe interactional flow about the same entity within the same QA control. This is particularly useful for more complex voice-only dialogs. So a mini-dialog which may involve different kinds of question and answer (e.g. asking, confirming, giving help, etc.), can be specified within the wrapper of the QA control associated with the visual control which represents the dialog entity. A complex QA control is illustrated in FIG. 10. The foregoing represent the main features of the QA control. Each feature is described from a functional perspective below. Answer Control The answer control 310A abstracts the notion of grammars, binding and other recognition processing into a single object or control. Answer controls 310A can be used to specify a set of possible grammars relevant to a question, along with binding declarations and relevant scripts. Answer controls for multimodal applications such as “Tap-and-Talk” are activated and deactivated by GUI browser events. The following example illustrates an answer control 310A used in a multimodal application to select a departure city on the “mouseDown” event of the textbox “txtDepCity”, and write its value into the primary textbox control: <Speech:QA controlsToSpeechEnable=”txtDepCity” runat=”server”> <Answer id=”AnsDepCity” StartEvent=”onMouseDown” StopEvent=”onMouseUp” /> <grammar src=”/grammars/depCities.gram”/> <bind value=”//sml/DepCity” targetElement=”txtCity” /> </Answer> </Speech:QA> Typical answer controls 310A in voice-only applications are activated directly by question controls 308A as described below. The answer control further includes a mechanism to associate a received result with the primary controls. Herein, binding places the values in the primary controls; however, in another embodiment the association mechanism may allow the primary control to look at or otherwise access the recognized results. Question Control Question controls 308A abstracts the notion of the prompt tags into an object which contains a selection of possible prompts and the answer controls 310A which are considered responses to the question. Each question control 308A is able to specify which answer control 310A it activates on its execution. This permits appropriate response grammars to be bundled into answer controls 310A, which reflect relevant question controls 308A. The following question control 308A might be used in a voice-only application to ask for a Departure City: <Speech:QA id=”QADepCity” controlsToSpeechEnable=”txtDepCity” runat=“server” > <Question id=”Q1” Answers=”AnsDepCity” > <prompt> Please give me the departure city. </prompt> </Question> <Answer id=”AnsDepCity” ... /> </Speech:QA> In the example below, different prompts can be called depending on an internal condition of the question control 308A. The ability to specify conditional tests on the prompts inside a question control 308A means that changes in wording can be accommodated within the same functional unit of the question control 308A. <Speech:QA id=”QADepCity” controlsToSpeechEnable=”txtDepCity” runat=“server” > <Question id=”Q1” Answers=”AnsDepCity” > <prompt count=”1”> Now I need to get the departure city. Where would you like to fly from? </prompt> <prompt count=”2”> Which departure city? </prompt> </Question> <Answer id=”AnsDepCity” ... /> </Speech:QA> Conditional QA Control The following example illustrates how to determine whether or not to activate a QA control based upon information known to the application. The example is a portion of a survey application. The survey is gathering information from employees regarding the mode of transportation they use to get to work. The portion of the survey first asks whether or not the user rides the bus to work. If the answer is: Yes, the next question asks how many days last week the users rode the bus. No, the “number of days rode the bus” question is bypassed. <asp:Label id=“lblDisplay1” text=“Do you ride the bus to work?” runat=“server”/> <asp:DropDownList id=“lstRodeBusYN” runat=“server”> <asp:ListItem selected=“true”>No</asp:ListItem> <asp:ListItem>Yes</asp:ListItem> </asp:DropDownList> <Speech:QA id=“QA_RideBus ControlsToSpeechEnable=“lstRodeBusYN” runat=“server” > <SDN:Question id=“Q_RideBus” > <prompt bargeIn=“False”> Do you ride the bus to work? </prompt> </SDN:Question> <SDN:Answer id=“A_RideBus” autobind=“False” StartEvent=“onMouseDown” StopEvent=“onMouseUp” runat=“server” onClientReco=“ProcessRideBusAnswer” <grammar src=“...” /> <--! “yes/no” grammar --> </SDN:Answer> </Speech:QA> <asp:Label id=“lblDisplay2” enabled=”False” text=“How many days last week did you ride the bus to work?” runat=“server”/> <asp:DropDownList id=“lstDaysRodeBus” enabled=”False” runat=“server”> <asp:ListItem selected=“true” >0</asp:ListItem> <asp:ListItem>1</asp:ListItem> <asp:ListItem>2</asp:ListItem> <asp:ListItem>3</asp:ListItem> <asp:ListItem>4</asp:ListItem> <asp:ListItem>5</asp:ListItem> <asp:ListItem>6</asp:ListItem> <asp:ListItem>7</asp:ListItem> </asp:DropDownList> <Speech:QA id=“QA_DaysRodeBus” ControlsToSpeechEnable=“lstDaysRodeBus” ClientTest=“RideBusCheck” runat=“server” > <Question id=“Q_DaysRodeBus” > <prompt bargeIn=“False”> How many days last week did you ride the bus to work? </prompt> </SDN:Question> <SDN:Answer id=“A_DaysRodeBus” autobind=“False” StartEvent=“onMouseDown” StopEvent=“onMouseUp” runat=“server” onClientReco=“ProcessDaysRodeBusAnswer” <grammar src=“...” /> <--! “numbers” grammar --> </SDN:Answer> </Speech:QA> <script language=“jscript”> function ProcessRideBusAnswer( ) { <--! using SML attribute of the Event object, determine yes or no answer --> <--! then select the appropriate item in the dropdown listbox <--! and enable the next label and dropdown listbox if answer is “yes” --> if <--! Answer is “yes” --> { lstRodeBusYN.selectedIndex=2 lblDisplay2.enabled=”true” lstDaysRodeBus.enabled=”true” } } function RideBusCheck( ) { if lstRodeBusYN.selectedIndex=“1” <--! this is no --> then return “False” endif } function ProcessDaysRodeBusAnswer( ) { <--! case statement to select proper dropdown item --> } </script> In the example provided above, the QA control “QA_DaysRodeBus” is executed based on a boolean parameter “ClientTest”, which in this example, is set based on the function RideBusCheck( ). If the function returns a false condition, the QA control is not activated, whereas if a true condition is returned the QA control is activated. The use of an activation mechanism allows increased flexibility and improved dialog flow in the client side markup page produced. As indicated in Appendix A many of the controls and objects include an activation mechanism. Command Control Command controls 310B are user utterances common in voice-only dialogs which typically have little semantic import in terms of the question asked, but rather seek assistance or effect navigation, e.g. help, cancel, repeat, etc. The Command control 310B within a QA control 306 can be used to specify not only the grammar and associated processing on recognition (rather like an answer control 310A without binding of the result to an input field), but also a ‘scope’ of context and a type. This allows for the authoring of both global and context-sensitive behavior on the client side markup. As appreciated by those skilled in the art from the foregoing description, controls 306 can be organized in a tree structure similar to that used in visual controls 302. Since each of the controls 306 are also associated with selected visual controls 302, the organization of the controls 306 can be related to the structure of the controls 302. The QA controls 302 may be used to speech-enable both atomic controls (textbox, label, etc.) and container controls (form, panel, etc.) This provides a way of scoping behavior and of obtaining modularity of subdialog controls. For example, the scope will allow the user of the client device to navigate to other portions of the client side markup page without completing a dialog. In one embodiment, “Scope” is determined as a node of the primary controls tree. The following is an example “help” command, scoped at the level of the “Pnl1” container control, which contains two textboxes. <asp:panel id=”Pnl1” ...> <asp:textbox id=”tb1” ... /> <asp:textbox id=”tb2” ... /> </asp:panel> <Speech:QA ... > <Command id=”HelpCmd1” scope=”Pnl1” type=”help” onClientReco=”GlobalGiveHelp( ) ” > <Grammar src=”grammars/help.gram”/> </Command> </Speech:QA> <script> function GlobalGiveHelp( ) { ... } </script> As specified, the “help” grammar will be active in every QA control relating to “Pnl1” and its contents. The GlobalGiveHelp subroutine will execute every time “help” is recognized. To override this and achieve context-sensitive behavior, the same typed command can be scoped to the required level of context: <Speech:QA ... > <Command id=”HelpCmd2” scope=”Tb2” type=”help” onClientReco=”SpecialGiveHelp( ) ” > <Grammar src=”grammars/help.gram”/> </Command> </Speech:QA> <script> function SpecialGiveHelp( ) { ... } </script> Confirmation Control The QA control 320 can also include a method for simplifying the authoring of common confirmation subdialogs. The following QA control exemplifies a typical subdialog which asks and then confirms a value: <Speech:QA id=”qaDepCity” controlsToSpeechEnable=”txtDepCity” runat=”server” > <!-- asking for a value --> <Question id=”AskDepCity” type=“ask” Answers=”AnsDepCity” > <prompt> Which city? </prompt> </Question> <Answer id=”AnsDepCity” confirmThreshold=”60” > <grammar src=”grammars/depCity.gram” /> </Answer> <!-- confirming the value --> <Confirm id=”ConfirmDepCity” Answers=”AnsConfDepCity” > <prompt> Did you say <value targetElement=“txtDepCity/Text”>? </prompt> </Confirm> <Answer id=”AnsConfDepCity” > <grammar src=”grammars/YesNoDepCity.gram” /> </Answer> </Speech:QA> In this example, a user response to ‘which city?’ which matches the AnsDepCity grammar but whose confidence level does not exceed the confirmThreshold value will trigger the confirm control 308. More flexible methods of confirmation available to the author include mechanisms using multiple question controls and multiple answer controls. In a further embodiment, additional input controls related to the confirmation control include an accept control, a deny control and a correct control. Each of these controls could be activated (in a manner similar to the other controls) by the corresponding confirmation control and include grammars to accept, deny or correct results, respectively. For instance, users are likely to deny be saying “no”, to accept by saying “yes” or “yes+current value” (e.g., “Do you want to go to Seattle?” “Yes, to Seattle”), to correct by saying “no”+new value (e.g., “Do you want to go to Seattle” “No, Pittsburgh”). Statement Control The statement control allows the application developer to provide an output upon execution of the client side markup when a response is not required from the user of the client device 30. An example could be a “Welcome” prompt played at the beginning of execution of a client side markup page. An attribute can be provided in the statement control to distinguish different types of information to be provided to the user of the client device. For instance, attributes can be provided to denote a warning message or a help message. These types could have different built-in properties such as different voices. If desired, different forms of statement controls can be provided, i.e. a help control, warning control, etc. Whether provided as separate controls or attributes of the statement control, the different types of statements have different roles in the dialog created, but share the fundamental role of providing information to the user of the client device without expecting an answer back. Eventing Event handlers as indicated in FIG. 10 are provided in the QA control 320, the output controls 308 and the input controls 310 for actions/inactions of the user of the client device 30 and for operation of the recognition server 204 to name a few, other events are specified in Appendix A. For instance, mumbling, where the speech recognizer detects that the user has spoken but is unable to recognize the words and silence, where speech is not detected at all, are specified in the QA control 320. These events reference client-side script functions defined by the author. In a multimodal application specified earlier, a simple mumble handler that puts an error message in the textbox could be written as follows: <Speech:QA controlsToSpeechEnable=”txtDepCity” y” onClientNoReco=”OnMumble( ) ” runat=”server”> <Answer id=”AnsDepCity” StartEvent=”onMouseDown” StopEvent=”onMouseUp” > <grammar src=”/grammars/depCities.gram”/> <bind value=”//sml/DepCity” targetElement=”txtCity” /> </Answer> </Speech:QA> <script> function OnMumble( ) { txtDepCity.value=“. . .recognition error. . .”; } </script> Control Execution Algorithm In one embodiment, a client-side script or module (herein referred to as “RunSpeech”) is provided to the client device. The purpose of this script is to execute dialog flow via logic, which is specified in the script when executed on the client device 30, i.e. when the markup pertaining to the controls is activated for execution on the client due to values contained therein. The script allows multiple dialog turns between page requests, and therefore, is particularly helpful for control of voice-only dialogs such as through telephony browser 216. The client-side script RunSpeech is executed in a loop manner on the client device 30 until a completed form in submitted, or a new page is otherwise requested from the client device 30. It should be noted that in one embodiment, the controls can activate each other (e.g. question control activating a selected answer control) due to values when executed on the client. However, in a further embodiment, the controls can “activate” each other in order to generate appropriate markup, in which case server-side processing may be implemented. Generally, in one embodiment, the algorithm generates a dialog turn by outputting speech and recognizing user input. The overall logic of the algorithm is as follows for a voice-only scenario: 1. Find next active output companion control; 2. If it is a statement, play the statement and go back to 1; If it is a question or a confirm go to 3; 3. Collect expected answers; 4. Collect commands; 5. Play output control and listen in for input; 6. Activate recognized Answer or Command object or, issue an event if none is recognized; 7. Go back to 1. In the multimodal case, the logic is simplified to the following algorithm: 1. Wait for triggering event—i.e., user tapping on a control; 2. Collect expected answers; 3. Listen in for input; 4. Activate recognized Answer object or, if none, throw event; 5. Go back to 1. The algorithm is relatively simple because, as noted above, controls contain built-in information about when they can be activated. The algorithm also makes use of the role of the controls in the dialogue. For example statements are played immediately, while questions and confirmations are only played once the expected answers have been collected. In a further embodiment, implicit confirmation can be provided whereby the system confirms a piece of information and asks a question at the same time. For example the system could confirm the arrival city of a flight and ask for the travel date in one utterance: “When do you want to go to Seattle?” (i.e. asking ‘when’ and implicitly confirming ‘destination: Seattle’). If the user gives a date then the city is considered implicitly accepted since, if the city was wrong, users would have immediately challenged it. In this scenario, it becomes clear that the knowledge of what a user is trying to achieve is vitally important: are they answering the question, or are they correcting the value, or are they asking for help? By using the role of the user input in the dialogue the system can know when to implicitly accept a value. In summary, a dialog is created due to the role of the control in the dialog and the relationship with other controls, wherein the algorithm executes the controls and thus manages the dialog. Each control contains information based on its type which is used by the execution algorithm to select (i.e. make active for execution) a given control according to whether or not it serves a useful purpose at that point in the dialog on the client. For example, confirmation controls are only active when there is a value to confirm and the system does not have sufficient confidence in that value to proceed. In a further implementation, most of these built-in pieces of information can be overridden or otherwise adapted by application developers. The following table summarizes the controls, their corresponding role in the dialog and the relationship with other controls. Relationship with other Control Role in dialogue controls Statement output: present (none) information to users Question output: ask selects expected Answers question as a response Confirmation output: confirm a selects potential input value obtained from controls as a response, the user typically Accept, Deny, Correct Answer input: provide an selected by answer to a Question/Confirmation question Command input: seek to scoped to other controls repair a dialog, or change the topic of conversation Accept input: confirm a selected by a value in response confirmation to a confirmation Deny input: deny a value selected by a in response to a confirmation confirmation Correct input: correct a selected by a value in response confirmation to a confirmation QA (wrapper: contains all the controls related to a specific topic) The use of these controls may be explained with an illustration of a simple human/computer dialog. In the dialog below, each dialog turn on the part of the System or the User is characterized according to the control (indicated in parentheses) which reflects its purpose in the dialog. 1. System (Statement): “Welcome to the travel booking service”. 2. System (Question): “Where would you like to go?” 3. User (Answer): “San Francisco.” 4. System (Confirmation): “Did you say Seattle?” 5. User (Deny): “No.” 6. System (Question): “Where would you like to go?” 7. User (Answer): “San Francisco.” 8. System (Confirmation): “Did you say Seattle?” 9. User (Correct): “I said San Francisco.” 10. System (Confirmation): “Did you say San Francisco?” 11. User (Correct): “Yes.” 12. System (Question): “When would you like to leave?” 13. User (Command): “Help.” Turn 1 is a statement on the part of the System. Since a statement control activates no answer controls in response, the system does not expect input. The system goes on to activate a question control at turn 2. This in turn activates a set of possible answer controls, including one which holds a grammar containing the cities available through the service, including “San Francisco”, “Seattle”, etc., which permits the user to provide such a city in turn 3. The user's turn 3 is misrecognized by the system. Although the system believes it has a value from an answer control for the city, its confidence in that value is low (rightly so, since it has recognized incorrectly). This low confidence value in a just-received answer control is sufficient information for RunSpeech to trigger a confirmation control on the part of the system, as generated at turn 4. The confirmation control in turn activates a deny control, a correct control and an accept control and makes their respective grammars available to recognize the user's next turn. User turns 5, 9 and 11 illustrate example responses for these controls. Turn 5 of the user simply denies the value “no”. This has the effect of removing the value from the system, so the next action of RunSpeech is to ask the question again to re-obtain the value (turn 6). Turns 7 and 8 return us to a confirmation control as with 3 and 4. User turn 9 is a correct control, which has again been activated as a possible response to the confirmation control. A correct control not only denies the value undergoing confirmation, it also provides a new value. So user turn 9 is recognized by the system as a correct control with a new value which, correctly this time, is recognized as “San Francisco”. The system's confidence in the new value is low, however, and yet another confirmation control is generated at turn 10. This in turn activates accept, deny and correct controls in response, and user turn 11 (“Yes” matches an accept control grammar. The recognition of the accept control has the effect of ‘grounding’ the system's belief in the value which it is trying to obtain, and so RunSpeech is now able to select other empty values to obtain. In turn 12, a new question control is output which asks for a date value. The user's response this time (turn 13) is a command: “help”. Command controls are typically activated in global fashion, that is, independently of the different question controls and confirmation controls on the part of the system. In this way the user is able to ask for help at any time, as he does in turn 13. Command controls may also be more sensitively enabled by a mechanism that scopes their activation according to which part of the primary control structure is being talked about. Referring back to the algorithm, in one exemplary embodiment, the client-side script RunSpeech examines the values inside each of the primary controls and an attribute of the QA control, and any selection test of the QA controls on the current page, and selects a single QA control for execution. For example, within the selected QA control, a single question and its corresponding prompt are selected for output, and then a grammar is activated related to typical answers to the corresponding question. Additional grammars may also be activated, in parallel, allowing other commands (or other answers), which are indicated as being allowable. Assuming recognition has been made and any further processing on the input data is complete, the client-side script RunSpeech will begin again to ascertain which QA control should be executed next. An exemplary implementation and algorithm of RunSpeech is provided in Appendix A. It should be noted that the use of the controls and the RunSpeech algorithm or module is not limited to the client/server application described above, but rather can be adapted for use with other application abstractions. For instance, an application such as VoiceXML, which runs only on the client device 30 or telephony voice browser 212, could conceivably include further elements or controls such as question and answer provided above as part of the VoiceXML browser and operating in the same manner. In this case the mechanisms of the RunSpeech algorithm described above could be executed by default by the browser without the necessity for extra script. Similarly, other platforms such as finite state machines can be adapted to include the controls and RunSpeech algorithm or module herein described. Synchronization As noted above, the companion controls 306 are associated with the primary controls 302 (the existing controls on the page). As such the companion controls 306 can re-use the business logic and presentation capabilities of the primary controls 302. This is done in two ways: storing values in the primary controls 302 and notifying the primary controls of the changes 302. The companion controls 306 synchronize or associates their values with the primary controls 302 via the mechanism called binding. Binding puts values retrieved from recognizer into the primary controls 302, for example putting text into a textbox, herein exemplified with the answer control. Since primary controls 302 are responsible for visual presentation, this provides visual feedback to the users in multimodal scenarios. The companion controls 306 also offer a mechanism to notify the primary controls 302 that they have received an input via the recognizer. This allows the primary controls 302 to take actions, such as invoking the business logic. (Since the notification amounts to a commitment of the companion controls 306 to the values which they write into the primary controls 302, the implementation provides a mechanism to control this notification with a fine degree of control. This control is provided by the RejectThreshold and ConfirmThreshold properties on the answer control, which specify numerical acoustic confidence values below which the system should respectively reject or attempt to confirm a value.) A second exemplary set of companion controls 400 is illustrated in FIG. 11. In this embodiment, the companion controls 400 generally include a QA control 402, a Command control 404, a CompareValidator control 406, a Custom Validator control 408 and a semantic map 410. The semantic map 410 is schematically illustrated and includes SemanticItemSemanticItems 412 that form a layer between the visual domain primary controls 402 (e.g. HTML and a non-visual recognition domain of the companion controls 400. At this point, it should be emphasized that that although the organization of the companion controls QA and Command is different than that of the first set of companion controls discussed above, the functionality remains the same. In particular, the QA control 402 includes a Prompt property that references Prompt objects to perform the functions of output controls, i.e. that provide “prompting” client side markups for human dialog, which typically involves the playing of a prerecorded audio file, or text for text-to-speech conversion, the data included in the markup directly or referenced via a URL. Likewise, the input controls are embodied as the QA control 402 and Command Control 404 and also follow human dialog and include the Prompt property (referencing a Prompt object) and an Answer property that references at least one Answer object. Both the QA control 402 and the Command control 404 associate a grammar with expected or possible input from the user of the client device 30. The QA control 402 in this embodiment can thus be considered a question control, an answer control as well as a confirm control and a statement control since it includes properties necessary for performing these functions. Although the QA control 402, Command control 404, Compare Validator control 406 and Custom Validator control 408 and other controls as well as the general structure of these controls, the parameters and event handlers, are specifically discussed with respect to use as companion controls 400, it should be understood that these controls, the general structure, parameters and event handlers can be adapted to provide recognition and/or audible prompting in the other two approaches discussed above with respect to FIGS. 6 and 7. For instance, the Semantic Map 410, which comprises another exemplary mechanism to form the association between the companion controls and visual control 302, would not be needed when embodied in the approaches of FIGS. 6 and 7. At this point, it may be helpful to provide a short description of each of the controls. Detailed descriptions are provided below in Appendix B. QA Control In general, the QA control 402 through the properties illustrated can perform one or more of the following: provide output audible prompting, collect input data, perform confidence validation of the input result, allow confirmation of input data and aid in control of dialog flow at the website, to name a few. In other words, the QA control 402 contains properties that function as controls for a specific topic. The QA control 402, like the other controls, is executed on the web server 202, which means it is defined on the application development web page held on the web server using the server-side markup formalism (ASP, JSP or the like), but is output as a different form of markup to the client device 30. Although illustrated in FIG. 11 where the QA control appears to be formed of all of the properties Prompt, Reco, Answers, ExtraAnswers and Confirms, it should be understood that these are merely options wherein one or more may be included for a QA control. At this point it may be helpful to explain use of the QA controls 402 in terms of application scenarios. Referring to FIG. 11 and in a voice-only application QA control 402 could function as a question and an answer in a dialog. The question would be provided by a Prompt object, while a grammar is defined through grammar object for recognition of the input data and related processing on that input. An Answers property associates the recognized result with a SemanticItem 412 in the Semantic Map 410 using an Answer object, which contains information on how to process recognition results. Line 414 represents the association of the QA control 402 with the Semantic Map 410, and to a SemanticItem 412 therein. Many SemanticItems 412 are individually associated with a visual or primary control 302 as represented by line 418, although one or more SemanticItems 412 may not be associated with a visual control and used only internally. In a multimodal scenario, where the user of the client device 30 may touch on the visual textbox, for example with a “TapEvent”, an audible prompt may not be necessary. For example, for a primary control comprising a textbox having visual text forming an indication of what the user of client device should enter in the corresponding field, a corresponding QA control 402 may or may not have a corresponding prompt such as an audio playback or a text-to-speech conversion, but would have a grammar corresponding to the expected value for recognition, and event handlers to process the input, or process other recognizer events such as no speech detected, speech not recognized, or events fired on timeouts. In a further embodiment, the recognition result includes a confidence level measure indicating the level of confidence that the recognized result was correct. A confirmation threshold can also be specified in the Answer object, for example, as ConfirmThreshold equals 0.7. If the confirmation level exceeds the associated threshold, the result can be considered confirmed. It should also be noted that in addition, or in the alternative, to specifying a grammar for speech recognition, QA controls and/or Command controls can specify Dtmf (dual tone modulated frequency) grammars to recognize telephone key activations in response to prompts or questions. Appendix B provides details of a Dtmf object that applies a different modality of grammar (a keypad input grammar rather than, for example, a speech input grammar) to the same question. Some of the properties of the Dtmf object include Preflush, which is a flag indicating if “type-ahead” functionality is allowed in order that the user can provide answers to questions before they are asked. Other properties include the number of milliseconds to wait for receiving the first key press, InitialTimeOut, and the number of milliseconds to wait before adjacent key presses, InterdigitTimeOut. Client-side script functions can be specified for execution through other properties, for example, when no key press is received, OnClientSilence, or when the input is not recognized, OnClientNoReco, or when an error is detected OnClientError. At this point it should be noted that when a SemanticItem 412 of the Semantic map 410 is filled, through recognition for example, speech or Dtmf, several actions can be taken. First, an event can be issued or fired indicating that the value has been “changed”. Depending on if the confirmation level was met, another event that can be issued or fired includes a “confirm” event that indicates that the corresponding SemanticItem has been confirmed. These events are used for controlling dialog. The Confirms property can also include answer objects having the structure similar to that described above with respect to the Answers property in that it is associated with a SemanticItem 412 and can include a ConfirmThreshold if desired. The Confirms property is not intended to obtain a recognition result per se, but rather, to confirm a result already obtained and ascertain from the user whether the result obtained is correct. The Confirms property is a collection of Answer objects used to ascertain whether the value of a previously obtained result was correct. The containing QA's Prompt object will inquire about these items, and obtains the recognition result from the associated SemanticItem 412 and forms it in a question such as “Did you say Seattle?” If the user responds with affirmation such as “Yes”, the confirmed event is then fired. If the user responds in the negative such as “No”, the associated SemanticItem 412 is cleared. It should be noted in a further embodiment, the Confirms property can also accept corrections after a confirmation prompt has been provided to the user. For instance, in response to a confirmation prompt “Did you say Seattle?” the user may respond “San Francisco” or “No, San Francisco”, in which case, the QA control has received a correction. Having information as to which SemanticItem is being confirmed through the Answer object, the value in the SemanticItem can be replaced with the corrected value. It should also be noted that if desired, confirmation can be included in a further prompt for information such as “When did you want to go to Seattle?”, where the prompt by the system includes a confirmation for “Seattle” and a further prompt for the day of departure. A response by the user providing a correction to the place of destination would activate the Confirms property to correct the associated SemanticItem, while a response with only a day of departure would provide implicit confirmation of the destination. The ExtraAnswers property allows the application author to specify Answer objects that a user may provide in addition to a prompt or query that has been made. For instance, if a travel oriented system prompts a user for a destination city, but the user responds by indicating “Seattle tomorrow”, the Answers property that initially prompted the user will retrieve and therefore bind the destination city “Seattle” to the appropriate SemanticItem, while the ExtraAnswers property can process “Tomorrow” as the next succeeding day (assuming that the system knows the current day), and thereby, bind this result to the appropriate SemanticItem in the Semantic Map. The ExtraAnswers property includes one or more Answer objects defined for possible extra information the user may also state. In the example provided above, having also retrieved information as to the day of departure, the system would then not need to reprompt the user for this information, assuming that the confirmation level exceeded the corresponding ConfirmThreshold. If the confirmation level did not exceed the corresponding threshold, the appropriate Confirms property would be activated. Command Control Command controls 404 are user utterances common in voice-only dialogs which typically have little semantic import in terms of the question asked, but rather seek assistance or effect navigation, e.g. help, cancel, repeat, etc. The Command control 404 can include a Prompt property to specify a prompt object. In addition, the Command control 404 can be used to specify not only the grammar (through a Grammar property) and associated processing on recognition (rather like an Answer object without binding of the result to an SemanticItem), but also a ‘scope’ of context and a type. This allows for the authoring of both global and context-sensitive behavior on the client side markup. The Command control 404 allows additional types of input such as “help” commands, or commands that allow the user of the client device to navigate to other selected areas of the website. CompareValidator Control The CompareValidator control compares two values according to an operator and takes an appropriate action. The values to be compared can be of any form such as integers, strings of text, etc. The CompareValidator includes a property SematicItemtoValidate that indicates the SemanticItem that will be validated. The SemanticItem to be validated can be compared to a constant or another SemanticItem, where the constant or other SemanticItem is provided by properties ValuetoCompare and SematicItemtoCompare, respectively. Other parameters or properties associated with the CompareValidator include Operator, which defines the comparison to be made and Type, which defines the type of value, for example, integer or string of the SemanticItems. If the validation associated with the CompareValidator control fails, a Prompt property can specify a Prompt object that can be played instructing the user that the result obtained was incorrect. If upon comparison the validation fails, the associated SemanticItem defined by SematicItemtoValidate is indicated as being empty, in order that the system will reprompt the user for a correct value. However, it may be helpful to not clear the incorrect value of the associated SemanticItem in the Semantic Map in the event that the incorrect value will be used in a prompt to the user reiterating the incorrect value. The CompareValidator control can be triggered either when the value of the associated SemanticItem changes value or when the value has been confirmed, depending on the desires of the application author. CustomValidator Control The CustomValidator control is similar to the CompareValidator control. A property SematicItemtoValidate indicates the SemanticItem that will be validated, while a property ClientValidationFunction specifies a custom validation routine through an associated function or script. The function would provide a Boolean value “yes” or “no” or an equivalent thereof whether or not the validation failed. A Prompt property can specify a Prompt object to provide indications of errors or failure of the validation. The CustomValidator control can be triggered either when the value of the associated SemanticItem changes value or when the value has been confirmed, depending on the desires of the application author. Call Control In a further embodiment, controls are provided that enable application authors to create speech applications that handle telephony transactions. In general, the controls implement or invoke well-known telephony transactions such as ECMA (European Computer Manufactures Associated) CSTA (Computer Supported Telecommunication Application) messages, eventing and services. As is known, CSTA specifies application interfaces and protocols for monitoring and controlling calls and devices in a communication network. These calls and devices may support various media and can reside in various network environments such as IP, Switched Circuit Networks and mobile networks. In the illustrated embodiment, the controls available to the application author include a SmexMessage control (SMEX-Simple Message Exchange), a TransferCall control, a MakeCall control, a DisconnectCall control and an AnswerCall control. Like the controls described above, these controls can be executed on the server so as to generate client-side markup that when executed on the client device perform the desired telephony transaction. Referring to FIG. 4, the client-side markup generated by server 202 can be executed by voice browser 216, which in turn provides telephony transactions instructions (e.g. CSTA service calls) to the media server 214 and gateway 210 as necessary to perform the desired telephony transaction. Appendix B provides detailed information regarding each of the properties available in the controls. The controls are commonly used in a voice-only mode such as by voice browser 216 in FIG. 4; however, it should be understood that applications can be written also to be executed in an multi-modal client device. Control Execution Algorithm As in the previous set of controls, a client-side script or module (herein referred to as “RunSpeech”) is provided to the client device for the controls of FIG. 11. Again, the purpose of this script is to execute dialog flow via logic, which is specified in the script when executed on the client device 30, i.e. when the markup pertaining to the controls is activated for execution on the client due to values contained therein. The script allows multiple dialog turns between page requests, and therefore, is particularly helpful for control of voice-only dialogs such as through telephony browser 216. The client-side script RunSpeech is executed in a loop manner on the client device 30 until a completed form is submitted, or a new page is otherwise requested from the client device 30. Generally, in one embodiment, the algorithm generates a dialog turn by outputting speech and recognizing user input. The overall logic of the algorithm is as follows for a voice-only scenario (reference is made to Appendix B for properties or parameters not otherwise discussed above): 1. Find the first active (as defined below) QA, CompareValidator or CustomValidator control in speech index order. 2. If there is no active control, submit the page. 3. Otherwise, run the control. A QA is considered active if and only if: 1. The QA's clientActivationFunction either is not present or returns true, AND 2. If the Answers property collection is non empty, the State of all of the SemanticItems pointed to by the set of Answers is Empty OR 3. If the Answers property collection is empty, the State at least one SemanticItem in the Confirm array is NeedsConfirmation. However, if the QA has PlayOnce true and its Prompt has been run successfully (reached OnComplete) the QA will not be a candidate for activation. A QA is run as follows: 1. If this is a different control than the previous active control, reset the prompt Count value. 2. Increment the Prompt count value 3. If PromptSelectFunction is specified, call the function and set the Prompt's inlinePrompt to the returned string. 4. If a Reco object is present, start it. This Reco should already include any active command grammar. A Validator (either a CompareValidator or a CustomValidator) is active if: 1. The SemanticItemToValidate has not been validated by this validator and its value has changed. A CompareValidator is run as follows: 1. Compare the values of the SemanticItemToCompare or ValueToCompare and SemanticItemToValidate according to the validator's Operator. 2. If the test returns false, empty the text field of the SemanticItemToValidate and play the prompt. 3. If the test returns true, mark the SemanticItemToValidate as validated by this validator. A CustomValidator is run as follows: 1. The ClientValidationFunction is called with the value of the SemanticItemToValidate. 2. If the function returns false, the semanticItem cleared and the prompt is played, otherwise as validated by this validator. A Command is considered active if and only if: 1. It is in Scope, AND 2. There is not another Command of the same Type lower in the scope tree. In the multi-modal case, the logic is simplified to the following algorithm: 1. Wait for triggering event—i.e., user tapping on a control; 2. Collect expected answers; 3. Listen in for input; 4. Bind result to SemanticItem, or if none, throw event; 5. Go back to 1. Application Controls Having described above QA control 402, Command control 404, CompareValidator control 406 and CustomValidator control 408, at this point it should be noted that one or more of these controls can be grouped or formed as an application control 430 as also illustrated in FIG. 11. In general, an application control 430 provides a means to wrap common speech scenarios in one control. In particular, an application control 430 can include one or more QA controls 402, one or more of the validator controls 406, 408 and one or more Command controls 404 as desired. An application control 430 would include all necessary prompts, for example, a prompt to solicit a question, to confirm a recognized result, or to specify that the recognized result is in error due to operation of a compare validator, etc. Commonly, application control 430 would also reference one or more SemanticItems 412 in the Semantic map 410 in order that the recognized results are placed in the Semantic map 410 with confirmation and validation performed as required, or as desired. In short, an application control 430, which can take many different forms, such as illustrated in Appendix C, allows the application author to rapidly develop an application by using application controls 430 rather than manually coding all the necessary syntax to perform a function, confirm the recognized result as well as perform any form of validation. The application control 430 receives parameters through properties that allows the application control 430 to generate the corresponding syntax of QA controls 402, Command controls 404, CustomValidator controls 408, CompareValidator controls 406 as if these controls were manually coded. This use of application controls 430 allows rapid development of a desired speech-enabled application. In the illustrative embodiment as described in Appendix C, an application control is derived from one of two base classes BasicApplicationControl[RL1] or ApplicationControl. Each class has associated therewith properties, which generally relate to information that is used in order to generate the syntax using QA controls, CompareValidator controls, CustomValidator controls and/or Command controls. The BasicApplicationControl includes properties that generally relate to asking a question and obtaining recognized results. This includes making a prompt (i.e. does the basic data acquisition) and specifying parameters such as BabbleTimeout, Bargein, if desired, as well as a property to be passed to all relevant internal QA controls that are used to process recognized results for words that do not impart semantic meaning. BasicApplicationControl also includes a property that specifies a client-side function that allows authors to select and/or modify a prompt string prior to playback. Although prompts could be encoded directly in the application control, in a further embodiment, all prompts are organized in a list, which can be selected as a function denoted in Appendix C as PromptSelectFunction. The ApplicationControl inherits all the properties associated with the BasicApplicationControl and contains further properties that an application control can support. For instance, for an applicaton control that is derived from the ApplicationControl class, internal QA controls created by the application control can specify a common threshold for accepting or rejection utterances pertaining to confirmation. Other properties that can be included in an application control include specifying the name of the event that starts or stops recognition in multi-modal mode such as on activation of a mouse button, for example, when depressed to start acquiring user voice input, whereas when the mouse button is released acquisition is stopped. Yet other properties specify the identifiers of the visual control that will issue the corresponding start and stop events. [RL2] It is worth noting that the BasicApplicationControl class and the ApplicationControl class may be merged to form a single class, as is known in the art. Other more specific base classes can also be used for specific applications and/or in order to generate customized application controls. Appendix C provides various application controls including an application control to retrieve a natural number, an application control to retrieve a string of numbers/letters and an application to navigate a table, which can also be used to select an item from a one column table or list. Dialogue Component Re-Use The following discussion regarding dialogue component re-use will be described with respect to the second version of companion controls as illustrated in FIG. 11 and described above. However, it should be understood that this is but one embodiment and the techniques described below with regard to processing recognition results, and particularly from mixed-initiative recognition results provided from [RL3] the user can be applied to the other embodiments described above. The foregoing algorithm for the voice-only scenario uses QA (Question-Answer) controls and the SemanticItem to formulate the dialogs. As described above each SemanticItem contains a recognition result, the confidence that the system has in it, and its current state. QA controls contain information, including prompts and grammars, that are used to ask questions, recognize answers and update the SemanticItems. QA controls also contain answer and extra-answers objects that are used to specify the QA activation logic and the processing to be done with the results. Both answers and extra-answers take the recognition results returned by the speech recognizer and update SemanticItems with the values extracted from the recognition results. The difference between answers and extra-answers lies in the activation logic used by the system: if a SemanticItem already contains a value, the system will not process answers related to it. On the other hand, extra-answers can be activated irrespective of whether their related SemanticItem already contains a value or not. Using the foregoing techniques, the following dialogue can be composed of two QAs. The first one contains a prompt to ask for a destination city and an answer dealing with the destination city. The second one contains a prompt and an answer dealing with the departure city. Sys: “Where do you want to go?” User: “I'd like to go to Seattle.” Sys: “Where are you leaving from?” User: “Paris.” It is fairly common when authoring dialogue that the same grammars and/or processing are used in several places. For example, application authors could add a new QA to the dialogue above that allows users to specify both cities (This is often referred to as ‘mixed-initiative’ dialogues). Sys: “Where do you want to go?” User: “I'd like to go from Paris to Seattle.” In this case the new QA would contain the information required to recognize and process the departure and destination cities. However, this information for recognizing and processing is equivalent to the information already contained in the existing QAs of the foregoing example where the user is solicited separately. Nevertheless, in order to allow application authors to accept a response having mixed-initiative (i.e., both the departure and destination cities), the application author would then have to duplicate the information necessary for asking, recognizing and processing users' answers as many times as needed. This aspect of the invention allows authors to re-use the information stored in QA controls without duplicating it in the code of the application design. In the example given above, the author could re-use the grammar and processing of the existing QAs of the first example where information is solicited separately and incorporate them into the new QA to allow a mixed-initiative dialogue. In general, one aspect of the invention, provides the ability to “import” the answer of the existing QAs as answers or extra-answers in the new QA. This is particularly useful when the information contained in a QA is expensive to create. For example, where the grammar used to recognize the spoken input, e.g. cities, may be created from a data source. This may be an operation that is best not to duplicate. In general, aspects described below allow an application author to specify the QA controls to re-use; to specify how the processing information from the QA controls will be combined; and how the grammars from the QA controls will be combined. In addition, application controls 430 described above, already include specified grammars as well as other processing such a validators, which allows them to conveniently serve as building block mechanisms for more rapid design. However, importing grammars into an application control is not convenient. Nevertheless, by using techniques herein described, it is possible to import a QA from an application control and thereby allow mixed-initiative dialogues with application controls. In order to allow an application author to specify QA controls to re-use and/or to specify how the processing information from the QA controls will be combine, each QA control or the QA control class includes two additional properties, herein referred to as “ImportedAnswerQAs” property and “ImportedExtraAnswerQAs” property. Each of these properties can be embodied as an array list or other mechanism that allows the application author to specify names or other suitable identifiers of QA controls whose processing information will be imported into the QA control referencing the QA controls identified in these properties. QA control 40 illustrated in FIG. 11 illustrates these additional properties[RL4]. FIG. 12 pictorially illustrates how a QA control having other QA controls listed in ImportedAnswerQAs property and ImportedExtraAnswerQAs property is modified. Referring first to the ImportedAnswerQAs″ property, the answers of the imported QA are added to the answers of the current QA, while the extra-answers of the imported QA are added to the extra-answers of the current QA. The ImportedAnswerQAs property thus provides an easy mechanism for simply re-using QA controls repeatedly in the application design without duplicating the complete QA control in the coded application specification. The ImportedExtraAnswerQAs property is similar, but the difference is that the answers and the extra-answers of the imported QA are both added to the extra-answers of the current QA. The ImportedExtraAnswerQAs property thus provides an easy mechanism for re-using an existing QA control to easily accommodate a mixed-initiative response from a user without duplicating it in the coded application specification. An example may serve to illustrate the usefulness of the ImportedAnswerQAs and ImportedExtraAnswerQAs properties. Suppose an author would like to create travel itinerary application that handled numerous forms of travel such as by airplane, train or bus. In each of these forms of travel, the user must be solicited for a departure city and a destination city. In one exemplary embodiment, the author may design a QA control herein referred to as “QADepartureCity” as well as a QA control herein referred to as “QADestinationCity”. Each of these controls can then be imported into other QA controls each designed specifically for a mode of transportation, i.e., airline (QATravelbyAir), train (QATravelbyTrain) or bus travel (QATravelbyBus), thereby obviating the need to duplicate the QA controls for the departure city and the destination city throughout the coded specification. The manner in which the generic controls of QADepartureCity and QADestinationCity are listed in the ImportedAnswerQAs and ImportedExtraAnswerQAs is under the application authors controls and is in part influenced by the prompt used in the current QA control. For instance, assume the prompt used by the QA control, QATravelbyAir was “What is your departure and destination cities?”, then for the ImportedAnswerQAs property of the QATravelbyAir control would include both QADepartureCity and QADestinationCity, since both are expected answers to be found in the user's response. In contrast, assume the prompt used by the QA control, QATravelbyAir was “What is your departure city?”, then for the ImportedAnswerQAs property of the QATravelbyAir control would include just QADepartureCity, while the ImportedExtraAnswerQAs property of the QATravelbyAir control would include QADestinationCity. In this example, it is expected that the user's response will include the departure city, but the user's response may also include his/her destination city as well. Importing the answers of a QA control consists in copying them to the proper list of the QA control receiving them (answers or extra-answers) as well as updating their corresponding XPath. As is known in the art, the “Xpath” is the location in which the system looks for each answer in the speech recognizer results (e.g. SML—Semantic Markup Language) from the recognition server such as server 204 in FIG. 4. For example the sentence “I'd like to go to Seattle” may be processed by the speech recognizer into an XML document with results of the form <SML><City>Seattle</City></SML>. The answer in the QA control processing the arrival city may then have an XPath trigger like “/SML/City” so that it can identify the city in the results. The answers of each control are associated [RL5] with one of the SemanticItems in the Semantic Map 410 with the city, herein “Seattle”, placed therein. The problem is that an imported answer from a QA control listed in the ImportedAnswerQAs and ImportedExtraAnswerQAs may have the same XPath trigger as an existing answer in the current QA control. Because the answers were originally processing different recognition results, it is not guaranteed that they have XPaths that don't collide, i.e. are the same. To avoid this problem, the system includes a mechanism such as processing code that appropriately modifies the Xpath trigger so as to avoid duplication. In the exemplary embodiment, this is accomplished by adding an extra layer, or additional text, in the Xpath trigger for each answer added from imported QA controls to the current QA control. For example, the /SML/City XPath will be modified into /SML/UniqueID/City where UniqueID is a unique identifier generated by the system. This removes XPath collisions between answers and imported answers since each Xpath trigger is unique. Since the speech recognizer uses a grammar to identify relevant information in the user's input, the grammar used by the speech recognizer is also adapted so that it produces results compatible with any extra layer or unique identify present in defined Xpath triggers. At this point it should be noted that the ordering of the original and imported answers in a QA control may be important. In one embodiment, this ordering is based on the order in which the QA controls are imported, i.e. listed in the ImportedAnswerQAs and ImportedExtraAnswerQAs properties. For instance, the application logic may need process one answer before another such as when validation limits are checked, or flags must be set, etc. Therefore, if the order processing answers is important, the order of the QA controls in the list of ImportedAnswerQAs and ImportedExtraAnswerQAs properties may need to be adjusted. Of course, other mechanisms specifying the order of answers in a QA control can be used when the answers from the imported QA controls are added to the current QA control. The foregoing has described use of the ImportedAnswerQAs and ImportedExtraAnswerQAs properties. In yet a further embodiment, an ImportedConfirmQAs property can also be included. This property can be embodied as an array list or other mechanism that allows the application author to specify names or other suitable identifiers of QA controls whose confirm processing information will be imported into the QA control referencing the QA controls identified in this property. In a manner similar to the ImportedAnswerQAs and ImportedExtraAnswerQAs properties, use of additional layers or additional text in the Xpath trigger, grammar, etc. may also be required to ensure proper processing of recognition results. As indicated above, it is also desirable to allow an application author to combine grammars. An aspect of the present invention provides a technique on how to specify and combine grammars. An example may also be helpful. Assume a first QA control recognizes and processes sentences like “I'd like to go to Paris” and a second QA control recognizes and processes sentences like “I'd like to leave from Boston”. It may be helpful to have a new QA control that can recognize and process sentences that combine these two QA controls. In the present invention, an application author can do this by specifying a grammar using a new “ruleref” construct. The “ruleref” element is the XML form of a known technique for referencing at least a portion (i.e. rulename) of a grammar, or the entire grammar if the root rule is referenced. The Speech Recognition Grammar Specification 1.0 W3C Candidate Recommendation 26 Jun. 2002 (available online at http://www.w3.org/TR/speech-grammar) describes the use of ruleref element as well as a similar rule referencing under ABNF (Augmented Backus-Naur Form). However, rather than simply importing a grammar from a grammar file (as ruleref usually does), this present ruleref imports the grammar contained in a specified QA control. An example is provided below. <grammar ...> <rule id=“Rule1”> <item> <one-of> <item>no<tag>$.deny = “no”;</tag></item> <item> yes <tag>$.accept = “yes”; </tag></item> <item> <item repeat=“0−1”>no</item> <item repeat=“0−1”><ruleref uri=“NaturalNumber1_question”/> </item> </item> </one-of> </item> </rule> </grammar> In this example, the ruleref references “NaturalNumber1_question”, which is QA control. However, this example demonstrates that the grammars of an application control can be accessed and combined or reused as well. In particular, the application control being accessed is “NaturalNumber1” with the grammar of the “question” QA control present in the “NaturalNumber1” application control being used. Upon encountering the special ruleref as provided above, the system will performs steps that include transforming the special ruleref into a regular ruleref, but more importantly, add the code needed to create an extra layer in the SML with a UniqueID, as described above, to avoid collisions between the results returned by the ruleref and other results. It should be understood that although the term “ruleref” has been used herein its operation and meaning is not the same as known in the art. For convenience and understanding to those skilled in the art use of the same term may help in understanding its use, but in the present application “ruleref” implicitly causes grammars to be combined, but does so by not referencing the grammars directly, but rather by referencing a QA control having the grammar. As demonstrated above, this technique further allows access and re-use of grammars contained in application controls. In a further embodiment, if recognition grammars are constructed so as to separate carrier phrases such as “I would like to go to”, “I want to go to” from the elements to be recognized such as a list of cities, the ruleref notation to a QA control can include an indicator or other parameter that signifies that only the grammar associated with only the elements to be recognized should be used and that the original carrier phrases of the QA control should be included. In this manner, an application author can write new grammars that allow recognition of sentences like ‘I’ d like to travel from Boston to Paris' where the original carrier phrases have been replaced by one or more different ones. Although combining grammars as described above includes referencing QA controls, it should be understood in an alternative embodiment suitable code or an external object can be provided to receive as an input the grammar to be added which is used to directly generate or modify the client side markup with such information. The final step in re-using a QA control is to specify what the new prompt should be. Because combining prompts automatically is non-trivial, authors can write new prompts using the usual QA approach (e.g., prompt select functions, data-bound prompts, etc.). Once the re-use information has been specified, the dialogue is run as usual by RunSpeech. The QA control will output the proper information to the client device and the dialogue will run as if the information had been duplicated within the server application. Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. Appendix A 1 QA Speech Control The QA control adds speech functionality to the primary control to which it is attached. Its object model is an abstraction of the content model of the exemplary tags in Appendix A. 1.1 QA Control <Speech:QA id=”...” controlsToSpeechEnable=”...” speechIndex=”...” ClientTest=”...” runat=”server” > <Question ...> <Statement ...> ... <Answer ...> <Confirm ...> ... <Command ...> ... </Speech:QA> 1.1.1 Core Properties string ControlsToSpeechEnable ControlsToSpeechEnable specifies the list of IDs of the primary controls to speech enable. IDs are comma delimited. 1.1.2 Activation Mechanisms int SpeechIndex SpeechIndex specifies the ordering information of the QA control—this is used by RunSpeech. Note: If more than one QA control has the same SpeechIndex, RunSpeech will execute them in source order. In situations where some QA controls have SpeechIndex specified and some QA controls do not, RunSpeech will order the QA controls first by SpeechIndex, then by source order. string ClientTest ClientTest specifies a client-side script function which returns a boolean value to determine when the QA control is considered available for selection by the RunSpeech algorithm. The system strategy can therefore be changed by using this as a condition to activate or de-activate QA controls more sensitively than SpeechIndex. If not specified, the QA control is considered available for activation. 1.1.3 Questions, Statements, Answers, Confirms and Commands Question[ ] Questions QA control contains an array of question objects or controls, defined by the dialog author. Each question control will typically relate to a function of the system, eg asking for a value, etc. Each question control may specify an activation function using the ClientTest attribute, so an active QA control may ask different kinds of questions about its primary control under different circumstances. For example, the activation condition for main question Q_Main may be that the corresponding primary control has no value, and the activation condition for a Q_GiveHelp may be that the user has just requested help. Each Question may specify answer controlss from within the QA control which are activated when the question control is outputted. Statement[ ] Statement QA control contains an array of statement objects or controls. Statements are used to provide information to the listener, such as welcome prompts. Answer[ ] Answers QA control contains an array of answer objects or controls. An answer control is activated directly by a question control within the QA control, or by a StartEvent from the Primary control. Where multiple answers are used, they will typically reflect answers to the system functions, e.g. A_Main might provide a value in response to Q_Main, and A_Confirm might providing a yes/no+correction to Confirm. Confirm[ ] Confirm QA control may contain a confirm object or control. This object is a mechanism provided to the dialog authors which simplify the authoring of common confirmation subdialogs. Command[ ] Command A Command array holds a set of command controls. Command controls can be thought of as answer controls without question controls, whose behavior on recognition can be scoped down the control tree. 1.2 Question Control The question control is used for the speech output relating to a given primary control. It contains a set of prompts for presenting information or asking a question, and a list of ids of the answer controls, which may provide an answer to that question. If multiple answer controls are specified, these grammars are loaded in parallel when the question is activated. An exception will be thrown if no answer control is specified in the question control. <Question id=”...” ClientTest=”...” Answers=”...” Count=”...” initialTimeout=”...” babbleTimeout=”...” maxTimeout=”...” Modal=”...” PromptFunction=”...” OnClientNoReco=”...” > <prompt ... /> ... </Question> string ClientTest ClientTest specifies the client-side script function returning a boolean value which determines under which circumstances a question control is considered active within its QA control (the QA control itself must be active for the question to be evaluated). For a given QA control, the first question control with a true condition is selected for output. For example, the function may be used to determine whether to output a question which asks for a value (“Which city do you want?”) or which attempts to confirm it (“Did you say London?”). If not specified, the question condition is considered true. Prompt[ ] Prompts The prompt array specifies a list of prompt objects, discussed below. Prompts are also able to specify conditions of selection (via client functions), and during RunSpeech execution only the first prompt with a true condition is selected for playback. String Answers Answers is an array of references by ID to controls that are possible answers to the question. The behavior is to activate the grammar from each valid answer control in response to the prompt asked by the question control. Integer initialTimeout The time in milliseconds between start of recognition and the detection of speech. This value is passed to the recognition platform, and if exceeded, an onSilence event will be thrown from the recognition platform. If not specified, the speech platform will use a default value. Integer babbleTimeout The period of time in milliseconds in which the recognition server or other recognizer must return a result after detection of speech. For recos in “tap-and-talk” scenarios this applies to the period between speech detection and the recognition result becoming available. For recos in dictation scenarios, this timeout applies to the period between speech detection and each recognition return—i.e. the period is restarted after each return of results or other event. If exceeded, the onClientNoReco event is thrown but different status codes are possible. If there has been any kind of recognition platform error that is detectable and the babbleTimeout period has elapsed, then an onClientNoReco is thrown but with a status code −3. Otherwise if the recognizer is still processing audio—e.g. in the case of an exceptionally long utterance or if the user has kept the pen down for an excessive amount of time—the onClientNoReco event is thrown, with status code −15. If babbleTimeout is not specified, the speech platform will default to an internal value. Integer maxTimeout The period of time in milliseconds between recognition start and results returned to the client device browser. If exceeded, the onMaxTimeout event is thrown by the browser—this caters for network or recognizer failure in distributed environments. For recos in dictation scenarios, as with babbleTimeout, the period is restarted after the return of each recognition or other event. Note that the maxTimeout attribute should be greater than or equal to the sum of initialTimeout and babbleTimeout. If not specified, the value will be a browser default. bool modal When modal is set to true, no answers except the immediate set of answers to the question are activated (i.e. no scoped Answers are considered). The defaults is false. For Example, this attribute allows the application developer to force the user of the client device to answer a particular question. String PromptFunction(prompt) PromptFunction specifies a client-side function that will be called once the question has been selected but before the prompt is played. This gives a chance to the application developer to perform last minute modifications to the prompt that may be required. PromptFunction takes the ID of the target prompt as a required parameter. string OnClientNoReco OnClientNoReco specifies the name of the client-side function to call when the NoReco (mumble) event is received. 1.2.1 Prompt Object The prompt object contains information on how to play prompts. All the properties defined are read/write properties. <prompt id=”...” count=”...” ClientTest=”...” source=”...” bargeIn=”...” onClientBargein=”...” onClientComplete=”...” onClientBookmark=”...” > ...text/markup of the prompt... </prompt> int count Count specifies an integer which is used for prompt selection. When the value of the count specified on a prompt matches the value of the count of its question control, the prompt is selected for playback. Legal values are 0-100. <Question id=Q_Ask”> <prompt count=“1”> Hello </prompt> <prompt count=“2”> Hello again </prompt> </Question> In the example, when Q_Ask.count is equal to 1, the first prompt is played, and if it is equal to 2 (i.e. the question has already been output before), the second prompt is then played. string ClientTest ClientTest specifies the client-side script function returning a boolean value which determines under which circumstances a prompt within an active question control will be selected for output. For a given question control, the first prompt with a true condition is selected. For example, the function may be used to implement prompt tapering, eg (“Which city would you like to depart from?” for a function returning true if the user if a first-timer, or “Which city?” for an old hand). If not specified, the prompt's condition is considered true. string InlinePrompt The prompt property contains the text of the prompt to play. This is defined as the content of the prompt element. It may contain further markup, as in TTS rendering information, or <value> elements. As with all parts of the page, it may also be specified as script code within <script> tags, for dynamic rendering of prompt output. string Source Source specifies the URL from which to retrieve the text of the prompt to play. If an inline prompt is specified, this property is ignored. Bool BargeIn BargeIn is used to specify whether or not barge-in (wherein the user of the client device begins speaking when a prompt is being played) is allowed on the prompt. The defaults is true. string onClientBargein onClientBargein specifies the client-side script function which is invoked by the bargein event. string onClientComplete onClientComplete specifies the client-side script function which is invoked when the playing of the prompt has competed. string OnClientBookmark OnClientBookmark accesses the name of the client-side function to call when a bookmark is encountered. 1.2.2 Prompt Selection On execution by RunSpeech, a QA control selects its prompt in the following way: ClientTest and the count attribute of each prompt are evaluated in order. The first prompt with both ClientTest and count true is played. A missing count is considered true. A missing ClientTest is considered true. 1.3 Statement Control Statement controls are used for information-giving system output when the activation of grammars is not required. This is common in voice-only dialogs. Statements are played only once per page if the playOnce attribute is true. <Statement id=”...” playOnce=”...” ClientTest=”...” PromptFunction=”...” > <prompt ... /> ... </Statement > bool playOnce The playOnce attribute specifies whether or not a statement control may be activated more than once per page. playOnce is a Boolean attribute with a default (if not specified) of TRUE, i.e., the statement control is executed only once. For example, the playOnce attribute may be used on statement controls whose purpose is to output email messages to the end user. Setting playOnce=“False” will provide dialog authors with the capability to enable a “repeat” functionality on a page that reads email messages. string ClientTest ClientTest specifies the client-side script function returning a boolean value which determines under which circumstances a statement control will be selected for output. RunSpeech will activate the first Statement with ClientTest equal to true. If not specified, the ClientTest condition is considered true. String PromptFunction PromptFunction specifies a client-side function that will be called once the statement control has been selected but before the prompt is played. This gives a chance to the authors to do last minute modifications to the prompt that may be required. Prompt[ ] Prompt The prompt array specifies a list of prompt objects. Prompts are also able to specify conditions of selection (via client functions), and during RunSpeech execution only the first prompt with a true condition is selected for playback. <Speech:QA id=”QA_Welcome” ControlsToSpeechEnable=”Label1” runat=”server” > <Statement id=”WelcomePrompt” > <prompt bargeIn=”False”> Welcome </prompt> </Statement> </Speech:QA> 1.4 Confirm Control Confirm controls are special types of question controls. They may hold all the properties and objects of other questions controls, but they are activated differently. The RunSpeech algorithm will check the confidence score found in the confirmThreshold of the answer control of the ControlsToSpeechEnable. If it is too low, the confirm control is activated. If the confidence score of the answer control is below the confirmThreshold, then the binding is done but the onClientReco method is not called. The dialog author may specify more than one confirm control per QA control. RunSpeech will determine which confirm control to activate based on the function specified by ClientTest. <Answer ConfirmThreshold=... /> <Confirm> ...all attributes and objects of Question... </Confirm> 1.5 Answer Control The answer control is used to specify speech input resources and features. It contains a set of grammars related to the primary control. Note that an answer may be used independently of a question, in multimodal applications without prompts, for example, or in telephony applications where user initiative may be enabled by extra-answers. Answer controls are activated directly by question controls, by a triggering event, or by virtue of explicit scope. An exception will be thrown if no grammar object is specified in the answer control. <Answer id=”...” scope=”...” StartEvent=”...” StopEvent=”...” ClientTest=”...” onClientReco=”...” onClientDTMF=”...” autobind=”...” server=”...” ConfirmThreshold=”...” RejectThreshold=”...” > <grammar ... /> <grammar ... /> ... <dtmf ... /> <dtmf ... /> ... <bind ... /> <bind ... /> ... </Answer> string Scope Scope holds the id of any named element on the page. Scope is used in answer control for scoping the availability of user initiative (mixed task initiative: i.e. service jump digressions) grammars. If scope is specified in an answer control, then it will be activated whenever a QA control corresponding to a primary control within the subtree of the contextual control is activated. string StartEvent StartEvent specifies the name of the event from the primary control that will activate the answer control (start the Reco object). This will be typically used in multi-modal applications, eg onMouseDown, for tap-and-talk. string StopEvent StopEvent specifies the name of the event from the primary control that will de-activate the answer control (stop the Reco object). This will be typically used in multi-modal applications, eg onMouseUp, for tap-and-talk. string ClientTest ClientTest specifies the client-side script function returning a boolean value which determines under which circumstances an answer control otherwise selected by scope or by a question control will be considered active. For example, the test could be used during confirmation for a ‘correction’ answer control to disable itself when activated by a question control, but mixed initiative is not desired (leaving only accept/deny answers controls active). Or a scoped answer control which permits a service jump can determine more flexible means of activation by specifying a test which is true or false depending on another part of the dialog. If not specified, the answer control's condition is considered true. Grammar[ ] Grammars Grammars accesses a list of grammar objects. DTMF[ ] DTMFs DTMFs holds an array of DTMF objects. Bind[ ] Binds Binds holds a list of the bind objects necessary to map the answer control grammar results (dtmf or spoken) into control values. All binds specified for an answer will be executed when the relevant output is recognized. If no bind is specified, the SML output returned by recognition will be bound to the control specified in the ControlsToSpeechEnable of the QA control. string OnClientReco OnClientReco specifies the name of the client-side function to call when spoken recognition results become available. string OnClientDTMF OnClientDTMF holds the name of the client-side function to call when DTMF recognition results become available. boolean autobind The value of autobind determines whether or not the system default bindings are implemented for a recognition return from the answer control. If unspecified, the default is true. Setting autobind to false is an instruction to the system not to perform the automatic binding. string server The server attribute is an optional attribute specifying the URI of the speech server to perform the recognition. This attribute over-rides the URI of the global speech server attribute. integer ConfirmThreshold Holds a value representing the confidence level below which a confirm control question will be automatically triggered immediately after an answer is recognized within the QA control. Legal values are 0-100. Note that where bind statements and onClientReco scripts are both specified, the semantics of the resulting Tags are that binds are implemented before the script specified in onClientReco. integer RejectThreshold RejectThreshold specifies the minimum confidence score to consider returning a recognized utterance. If overall confidence is below this level, a NoReco event will be thrown. Legal values are 0-100. 1.5.1 Grammar The grammar object contains information on the selection and content of grammars, and the means for processing recognition results. All the properties defined are read/write properties. <Grammar ClientTest=”...” Source=”...” > ...grammar rules... </Grammar> string ClientTest The ClientTest property references a client-side boolean function which determines under which conditions a grammar is active. If multiple grammars are specified within an answer control (e.g. to implement a system/mixed initiative strategy, or to reduce the perplexity of possible answers when the dialog is going badly), only the first grammar with a true ClientTest function will be selected for activation during RunSpeech execution. If this property is unspecified, true is assumed. string Source Source accesses the URI of the grammar to load, if specified. string InlineGrammar InlineGrammar accesses the text of the grammar if specified inline. If that property is not empty, the Source attribute is ignored. 1.5.2 Bind The object model for bind follows closely its counterpart client side tags. Binds may be specified both for spoken grammar and for DTMF recognition returns in a single answer control. <bind Value=”...” TargetElement=”...” TargetAttribute=”...” Test=”...” /> string Value Value specifies the text that will be bound into the target element. It is specified as an XPath on the SML output from recognition. string TargetElement TargetElement specifies the id of the primary control to which the bind statement applies. If not specified, this is assumed to be the ControlsToSpeechEnable of the relevant QA control. string TargetAttribute TargetAttribute specifies the attribute on the TargetElement control in which bind the value. If not specified, this is assumed to be the Text property of the target element. string Test The Test attribute specifies a condition which must evaluate to true on the binding mechanism. This is specified as an XML Pattern on the SML output from recognition. 1.5.2.1 Automatic Binding The default behavior on the recognition return to a speech-enabled primary control is to bind certain properties into that primary control. This is useful for the dialog controls to examine the recognition results from the primary controls across turns (and even pages). Answer controls will perform the following actions upon receiving recognition results: 1. bind the SML output tree into the SML attribute of the primary control 2. bind the text of the utterance into the SpokenText attribute of the primary control 3. bind the confidence score returned by the recognizer into the Confidence attribute of the primary control. Unless autobind=“False” attribute is specified on an answer control, the answer control will perform the following actions on the primary control: 1. bind the SML output tree into the SML attribute; 2. bind the text of the utterance into the SpokenText attribute; 3. bind the confidence score returned by the recognizer into the Confidence attribute; Any values already held in the attribute will be overwritten. Automatic binding occurs before any author-specified bind commands, and hence before any onClientReco script (which may also bind to these properties). 1.5.3 DTMF DTMF may be used by answer controls in telephony applications. The DTMF object essentially applies a different modality of grammar (a keypad input grammar rather than a speech input grammar) to the same answer. The DTMF content model closely matches that of the client side output Tags DTMF element. Binding mechanisms for DTMF returns are specified using the targetAttribute attribute of DTMF object. <DTMF firstTimeOut=”...” interDigitTimeOut=”...” numDigits=”...” flush=”...” escape=”...” targetAttribute=”...” ClientTest=”...”> <dtmfGrammar ...> </DTMF> integer firstTimeOut The number of milliseconds to wait between activation and the first key press before raising a timeout event. integer interDigitTimeOut The number of milliseconds to wait between key presses before raising a timeout event. int numDigits The maximum number of key inputs permitted during DTMF recognition. bool flush A flag which states whether or not to flush the telephony server's DTMF buffer before recognition begins. Setting flush to false permits DTMF key input to be stored between recognition/page calls, which permits the user to ‘type-ahead’. string escape Holds the string value of the key which will be used to end DTMF recognition (eg ‘#’). string targetAttribute TargetAttribute specifies the property on the primary control in which to bind the value. If not specified, this is assumed to be the Text property of the primary control. string ClientTest The ClientTest property references a client-side boolean function which determines under which conditions a DTMF grammar is active. If multiple grammars are specified within a DTMF object, only the first grammar with a true ClientTest function will be selected for activation during RunSpeech execution. If this property is unspecified, true is assumed. 1.5.4 DTMFGrammar DTMFGrammar maps a key to an output value associated with the key. The following sample shows how to map the “1” and “2” keys to text output values. <dtmfgrammar> <key value=”1”>Seattle</key> <key value=”2”>Boston</key> </dtmfgrammar> 1.6 Command Control The command control is a special variation of answer control which can be defined in any QA control. Command controls are forms of user input which are not answers to the question at hand (eg, Help, Repeat, Cancel), and which do not need to bind recognition results into primary controls. If the QA control specifies an activation scope, the command grammar is active for every QA control within that scope. Hence a command does not need to be activated directly by a question control or an event, and its grammars are activated in parallel independently of answer controls building process. Command controls of the same type at QA controls lower in scope can override superior commands with context-sensitive behavior (and even different/extended grammars if necessary). <Command id=”...” scope=”...” type=”...” RejectThreshold=”...” onClientReco=”...” > <Grammar ...> <dtmf ... > ... </Command> string Scope Scope holds the id of a primary control. Scope is used in command controls for scoping the availability of the command grammars. If scope is specified for a command control, the command's grammars will be activated whenever a QA control corresponding to a primary control within the subtree of the contextual control is activated. string type Type specifies the type of command (eg ‘help’, ‘cancel’ etc.) in order to allow the overriding of identically typed commands at lower levels of the scope tree. Any string value is possible in this attribute, so it is up to the author to ensure that types are used correctly. integer RejectThreshold RejectThreshold specifies the minimum confidence level of recognition that is necessary to trigger the command in recognition (this is likely to be used when higher than usual confidence is required, eg before executing the result of a ‘Cancel’ command). Legal values are 0-100. string onClientReco onCommand specifies the client-side script function to execute on recognition of the command control's grammar. Grammar Grammar The grammar object which will listen for the command. DTMF DTMF The dtmf object which will activate the command. 2 Types of Initiatives and Dialog Flows Using the control described above, various forms of initiatives can be developed, some examples are provided below: 2.1 Mixed Initiative Dialogs Mixed initiative dialogs provide the capability of accepting input for multiple controls with the asking of a single question. For example, the answer to the question “what are your travel plans” may provide values for an origin city textbox control, a destination city textbox control and a calendar control (“Fly from Puyallup to Yakima on September 30th”). A robust way to encode mixed initiative dialogs is to handwrite the mixed initiative grammar and relevant binding statements, and apply these to a single control. The following example shows a single page used for a simple mixed initiative voice interaction about travel. The first QA control specifies the mixed initiative grammar and binding, and a relevant prompt asking for two items. The second and third QA controls are not mixed initiative, and so bind directly to their respective primary control by default (so no bind statements are required). The RunSpeech algorithm will select the QA controls based on an attribure “SpeechIndex” and whether or not their primary controls hold valid values. <%@ Page language=“c#” AutoEventWireup=“false” inherits=“SDN.Page” %> <%@ Register tagPrefix=“SDN” Namespace=“SDN” Assembly=“SDN” %> <html> <body> <Form id=“WebForm1” method=post runat=“server”> <ASP:Label id=“Label1” runat=“server”>Departure city</ASP:Label> <ASP:TextBox id=“TextBox1” runat=“server” /> <br> <ASP:Label id=“Label2” runat=“server”>Arrival city</ASP:Label> <ASP:TextBox id=“TextBox2” textchanged=“TextChanged” runat=“server” /> <!-speech information --> <Speech:QA id=”QAmixed” controlsToSpeechEnable=”TextBox1” speechIndex=”1” runat=“server”> <Question id=”Q1” Answers=”A1”> <prompt>”Please say the cities you want to fly from and to”</prompt> </Question> <Answer id=”A1” > <grammar src=”...”/> <bind targetElement=”TextBox1” value=”/sml/path1”/> <bind targetElement=”TextBox2” value=”/sml/path2”/> </Answer> </Speech:QA> <Speech:QA id=”QA1” controlsToSpeechEnable=”TextBox1” speechIndex=”2” runat=“server”> <Question id=”Q1” Answers=”A1”> <prompt>”What's the departure city?”</prompt> </Question> <Answer id=”A1”> <grammar src=”...”/> </Answer> </Speech:QA> <Speech:QA id=”QA2” controlsToSpeechEnable=”TextBox2” speechIndex=”3” runat=“server”> <Question id=”Q1” Answer=”A1”> <prompt>”What's the arrival city”</prompt> </Question> <Answer id=”A1” > <grammar src=”...”/> </Answer> </Speech:QA> </Form> </body> </html> 2.2 Complex Mixed Initiative Application developers can specify several answer to the same question control with different levels of initiatives. Conditions are specified that will select one of the answers when the question is asked, depending on the initiative settings that they require. An example is provided below: <Speech:QA id=”QA_Panel2” ControlsToSpeechEnable=”Panel2” runat=”server” > <Question answers=”systemInitiative, mixedInitiative” .../> <Answer id=”systemInitiative” ClientTest=”systemInitiativeCond” onClientReco=”SimpleUpdate” > <grammar src=”systemInitiative.gram” /> </Answer> <Answer id=”mixedInitiative” ClientTest=”mixedInitiativeCond” onClientReco=”MixedUpdate” > <grammar src=”mixedInitiative.gram” /> </Answer> </Speech:QA> Application developers can also specify several question controls in a QA control. Some question controls can allow a mixed initiative style of answer, whilst others are more directed. By authoring conditions on these question controls, application developer can select between the questions depending on the dialogue situation. In the following example the mixed initiative question asks the value of the two textboxes at the same time (e.g., ‘what are your travel plans?’) and calls the mixed initiative answer (e.g., ‘from London to Seattle’). If this fails, then the value of each textbox is asked separately (e.g., ‘where do you leave from’ and ‘where are you going to’) but, depending on the conditions, the mixed-initiative grammar may still be activated, thus allowing users to provide both values. <Speech:QA id=”QA_Panel2” ControlsToSpeechEnable=”TextBox1, TextBox2” runat=”server” > <Question ClientTest=”AllEmpty( )” answers=”AnsAll” .../> <Question ClientTest=”TextBox1IsEmpty( )” answers=”AnsAll, AnsTextBox1” .../> <Question ClientTest=”TextBox2IsEmpty( )” answers=”AnsAll, AnsTextBox2” .../> <Answer id=”AnsTextBox1” onClientReco=”SimpleUpdate”> <grammar src=”AnsTextBox1.gram” /> </Answer> <Answer id=”AnsTextBox2” onClientReco=”SimpleUpdate” > <grammar src=” AnsTextBox2.gram” /> </Answer> <Answer id=”AnsAll” ClientTest=”IsMixedInitAllowed( )” onClientReco=”MixedUpdate” > <grammar src=”AnsAll.gram” /> </Answer> </Speech:QA> 2.3 User Initiative Similar to the command control, a standard QA control can specify a scope for the activation of its grammars. Like a command control, this QA control will activate the grammar from a relevant answer control whenever another QA control is activated within the scope of this context. Note that its question control will only be asked if the QA control itself is activated. <Speech:QA id=”QA_Panel2” ControlsToSpeechEnable=”Panel2” runat=”server” > <Question ... /> <Answer id=”AnswerPanel2” scope=”Panel2” onClientReco=”UpdatePanel2( )” > <grammar src=”Panel2.gram” /> </Answer> </Speech:QA> This is useful for dialogs which allow ‘service jumping’—user responses about some part of the dialog which is not directly related to the question control at hand. 2.4 Short Time-Out Confirms Application developers can write a confirmation as usual but set a short time-out. In the timeout handler, code is provided to that accept the current value as exact. <Speech:QA id=”QA_Panel2” ControlsToSpeechEnable=”Panel2” runat=”server” > <Confirm timeOut=”20” onClientTimeOut=”AcceptConfirmation”... /> <Answer id=”CorrectPanel2” onClientReco=”UpdatePanel2( )” > <grammar src=”Panel2.gram” /> </Answer> </Speech:QA> 2.5 Dynamic Prompt Building and Editing The promptFunction script is called after a question control is selected but before a prompt is chosen and played. This lets application developers build or modify the prompt at the last minute. In the example below, this is used to change the prompt depending on the level of experience of the users. <script language=javascript> function GetPrompt( ) { if(experiencedUser == true) Prompt1.Text = “What service do you want?”; else Prompt1.Text = “Please choose between e-mail, calendar and news”; return; } </script> <Speech:QA id=”QA_Panel2” ControlsToSpeechEnable=”Panel2” runat=”server” > <Question PromptFunction=”GetPrompt”... > <Prompt id=”Prompt1” /> </Question> <Answer ... /> </Speech:QA> 2.6 Using Semantic Relationships Recognition and use of semantic relationships can be done by studying the result of the recognizer inside the onReco event handler. <script language=”javascript”> function Reco( ) { /* Application developers can access the SML returned by the recogniser or recognition server. If a semantic relationship (like sport-news) is identified, the confidence of the individual elements can be increased or take any other appropriate action. */ } </script> <Speech:QA id=”QA_Panel2” ControlsToSpeechEnable=”Panel2” runat=”server” > <Question ... /> <Answer onClientReco=”Reco” > <grammar src=”Panel2.gram” /> </Answer> </Speech:QA> 3 Implementation and Application of RunSpeech A mechanism is needed to provide voice-only clients with the information necessary to properly render speech-enabled pages. Such a mechanism must provide the execution of dialog logic and maintain state of user prompting and grammar activation as specified by the application developer. Such a mechanism is not needed for multimodal clients. In the multimodal case, the page containing speech-enabled controls is visible to the user of the client device. The user of the client device may provide speech input into any visible speech-enabled control in any desired order using the a multimodal paradigm. The mechanism used by voice-only clients to render speech-enabled pages is the RunSpeech script or algorithm. The RunSpeech script relies upon the SpeechIndex attribute of the QA control and the SpeechGroup control discussed below. 3.1 SpeechControl During run time, the system parses a control script or webpage having the server controls and creates a tree structure of server controls. Normally the root of the tree is the Page control. If the control script uses custom or user control, the children tree of this custom or user control is expanded. Every node in the tree has an ID and it is easy to have name conflict in the tree when it expands. To deal with possible name conflict, the system includes a concept of NamingContainer. Any node in the tree can implement NamingContainer and its children lives within that name space. The QA controls can appear anywhere in the server control tree. In order to easily deal with SpeechIndex and manage client side rendering, a SpeechGroup control is provided. The Speechgroup control is hidden from application developer. One SpeechGroup control is created and logically attached to every NamingContainer node that contain QA controls in its children tree. QA and SpeechGroup controls are considered members of its direct NamingContainer's SpeechGroup. The top level SpeechGroup control is attached to the Page object. This membership logically constructs a tree—a logical speech tree—of QA controls and SpeechGroup controls. For simple speech-enabled pages or script (i.e., pages that do not contain other NamingContainers), only the root SpeechGroup control is generated and placed in the page's server control tree before the page is sent to the voice-only client. The SpeechGroup control maintains information regarding the number and rendering order of QA controls on the page. For pages containing a combination of QA control(s) and NamingContainer(s), multiple SpeechGroup controls are generated: one SpeechGroup control for the page (as described above) and a SpeechGroup control for each NamingContainer. For a page containing NamingContainers, the page-level SpeechGroup control maintains QA control information as described above as well as number and rendering order of composite controls. The SpeechGroup control associated with each NamingContainer maintains the number and rendering order of QAs within each composite. The main job of the SpeechGroup control is to maintain the list of QA controls and SpeechGroups on each page and/or the list of QA controls comprising a composite control. When the client side markup script (e.g. HTML) is generated, each SpeechGroup writes out a QACollection object on the client side. A QACollection has a list of QA controls and QACollections. This corresponds to the logical server side speech tree. The RunSpeech script will query the page-level QACollection object for the next QA control to invoke during voice-only dialog processing. The page level SpeechGroup control located on each page is also responsible for: Determining that the requesting client is a voice-only client; and Generating common script and supporting structures for all QA controls on each page. When the first SpeechGroup control renders, it queries the System.Web.UI.Page.Request.Browser property for the browser string. This property is then passed to the RenderSpeechHTML and RenderSpeechScript methods for each QA control on the page. The QA control will then render for the appropriate client (multimodal or voice-only). 3.2 Creation of SpeechGroup Controls During server-side page loading, the onLoad event is sent to each control on the page. The page-level SpeechGroup control is created by the first QA control receiving the onLoad event. The creation of SpeechGroup controls is done in the following manner: (assume a page containing composite controls) Every QA control will receive onLoad event from run time code. onLoad for a QA: Get the QA's NamingContainer N1 Search for SpeechGroup in the N1's children If already exists, register QA control with this SpeechGroup. onLoad returns. If not found: Create a new SpeechGroup G1, inserts it into the N1's children If N1 is not Page, find N1's NamingContainer N2 Search for SpeechGroup in N2's children, if exists, say G2, add G1 to G2. If not, create a new one G2, inserts in to N2's children Recursion until the NamingContainer is the Page (top level) During server-side page rendering, the Render event is sent to the speech-enabled page. When the page-level SpeechGroup control receives the Render event, it generates client side script to include RunSpeech.js and inserts it into the page that is eventually sent to the client device. It also calls all its direct children to render speech related HTML and scripts. If a child is SpeechGroup, the child in turn calls its children again. In this manner, the server rendering happens along the server side logical speech tree. When a SpeechGroup renders, it lets its children (which can be either QA or SpeechGroup) render speech HTML and scripts in the order of their SpeechIndex. But a SpeechGroup is hidden and doesn't naturally have a SpeechIndex. In fact, a SpeechGroup will have the same SpeechIndex as its NamingContainer, the one it attaches to. The NamingContainer is usually a UserControl or other visible control, and an author can set SpeechIndex to it. 3.3 RunSpeech The purpose of RunSpeech is to permit dialog flow via logic which is specified in script or logic on the client. In one embodiment, RunSpeech is specified in an external script file, and loaded by a single line generated by the server-side rendering of the SpeechGroup control, e.g.: <script language=“javascript” src=“/scripts/RunSpeech.js” /> The RunSpeech.js script file should expose a means for validating on the client that the script has loaded correctly and has the right version id, etc. The actual validation script will be automatically generated by the page class as inline functions that are executed after the attempt to load the file. Linking to an external script is functionally equivalent to specifying it inline, yet it is both more efficient, since browsers are able to cache the file, and cleaner, since the page is not cluttered with generic functions. 3.4 Events 3.4.1 Event Wiring Tap-and-talk multimodality can be enabled by coordinating the activation of grammars with the onMouseDown event. The wiring script to do this will be generated by the Page based on the relationship between controls (as specified in the ControlsToSpeechEnable property of the QA control in). For example, given an asp:TextBox and its companion QA control adding a grammar, the <input> and <reco> elements are output by each control's Render method. The wiring mechanism to add the grammar activation command is performed by client-side script generated by the Page, which changes the attribute of the primary control to add the activation command before any existing handler for the activation event: <!-- Control output --> <input id=”TextBox1” type=”text” .../> <reco id=”Reco1” ... /> <grammar src=”...” /> </reco> <!-- Page output --> <script> TextBox1.onMouseDown = “Reco1.Start( );”+TextBox1.onMouseDown; </script> By default, hook up is via onmousedown and onmouseup events, but both StartEvent and StopEvent can be set by web page author. The textbox output remains independent of this modification and the event is processed as normal if other handlers were present. 3.4.2 Page Class Properties The Page also contains the following properties which are available to the script at runtime: SML—a name/value pair for the ID of the control and it's associated SML returned by recognition. SpokenText—a name/value pair for the ID of the control and it's associated recognized utterance Confidence—a name/value pair for the ID of the control and it's associated confidence returned by the recognizer. 4 RunSpeech Algorithm The RunSpeech algorithm is used to drive dialog flow on the client device. This may involve system prompting and dialog management (typically for voice-only dialogs), and/or processing of speech input (voice-only and multimodal dialogs). It is specified as a script file referenced by URI from every relevant speech-enabled page (equivalent to inline embedded script). Rendering of the page for voice only browsers is done in the following manner: The RunSpeech module or function works as follows (RunSpeech is called in response to document.onreadystate becoming “complete”): (1) Find the first active QA control in speech index order (determining whether a QA control is active is explained below). (2) If there is no active QA control, submit the page. (3) Otherwise, run the QA control. A QA control is considered active if and only if: (1) The QA control's ClientTest either is not present or returns true, AND (2) The QA control contains an active question control or statement control (tested in source order), AND (3) Either: a. The QA control contains only statement controls, OR b. At least one of the controls referenced by the QA control's ControlsToSpeechEnable has an empty or default value. A question control is considered active if and only if: (1) The question control's ClientTest either is not present or returns true, AND (2) The question control contains an active prompt object. A prompt object is considered active if and only if: (1) The prompt object's ClientTest either is not present or returns true, AND (2) The prompt object's Count is either not present, or is less than or equal to the Count of the parent question control. A QA control is run as follows: (1) Determine which question control or statement control is active and increment its Count. (2) If a statement control is active, play the prompt and exit. (3) If a question control is active, play the prompt and start the Recos for each active answer control and command control. An answer control is considered active if and only if: (1) The answer control's ClientTest either is not present or returns true, AND (2) Either: a. The answer control was referenced in the active question contol's Answers string, OR b. The answer control is in Scope A command control is considered active if and only if: (1) It is in Scope, AND (2) There is not another command control of the same Type lower in the scope tree. RunSpeech relies on events to continue driving the dialog—as described so far it would stop after running a single QA control. Event handlers are included for Prompt.OnComplete, Reco.OnReco, Reco.OnSilence, Reco.OnMaxTimeout, and Reco.OnNoReco. Each of these will be described in turn. RunSpeechOnComplete works as follows: (1) If the active Prompt object has an OnClientComplete function specified, it is called. (2) If the active Prompt object was contained within a statement control, or a question control which had no active answer controls, RunSpeech is called. RunSpeechOnReco works as follows: (1) Some default binding happens—the SML tree is bound to the SML attribute and the text is bound to the SpokenText attribute of each control in ControlsToSpeechEnable. (2) If the confidence value of the recognition result is below the ConfidenceThreshold of the active answer control, the Confirmation logic is run. (3) Otherwise, if the active answer control has on OnClientReco function specified, it is called, and then RunSpeech is called. RunSpeechOnReco is responsible for creating and setting the SML, SpokenText and Confidence properties of the ControlsToSpeechEnable. The SML, SpokenText and Confidence properties are then available to scripts at runtime. RunSpeechOnSilence, RunSpeechOnMaxTimeout, and RunSpeechOnNoReco all work the same way: (1) The appropriate OnClientXXX function is called, if specified. (2) RunSpeech is called. Finally, the Confirmation logic works as follows: (1) If the parent QA control of the active answer control contains any confirm controls, the first active confirm control is found (the activation of a confirm control is determined in exactly the same way as the activation of a question control). (2) If no active confirm control is found, RunSpeech is called. (3) Else, the QA control is run, with the selected confirm control as the active question control. For multi-modal browsers, only the grammar loading and event dispatching steps are carried out. Appendix B 1 Design Principles In this embodiment, there is no concept of primary control to speech-enable as it existed in Appendix A. The speech layer provides input to the visual layer as well as explicit support for dialog flow management. The semantic layer implements the logic needed for confirmation and validation. In a multimodal interaction, the semantic layer does not need to be used as confirmation and validation are visual and implemented using standard ASP.NET constructs. If desired though, the sematic layer can be updated with value changes made through visual or GUI interfaces in order that confirmation and validation can be still implemented. FIG. 12 illustrates the speech controls inheritance diagram. 2 Authoring Scenarios The following provides examples of various forms of application scenarios. 2.1 Multimodal App, Tap-and-Talk <speech:QA id=“qa1” runat=“server”> <Answers> <speech:Answer SemanticItem=“siText” ID=“answer1” XpathTrigger=“/sml/value” runat=“server”> </speech:Answer> </Answers> <Reco StartEvent=“textbox1.onmousedown” StopEvent=“textbox1.onmouseup” ID=“reco1” Mode=“Single”> <Grammars> <speech Grammar Src=“http://mysite/mygrammar.grxml” ID=“Grammar1” runat=“server”> </speech:Grammar> </Grammars> </Reco> </speech:QA> 2.2 Multimodal App, Click-and-Wait-for-Recognition <speech:QA id=“qa1” runat=“server”> <Reco id=“reco1” StartEvent=“textbox1.onmousedown” mode=“automatic”> <Grammars> <speech:grammar src=“htp://mysite/mygrammar.grxml” rnat=“server”></speech:grammar> </Grammars> </Reco> <Answers> <speech:answer id=“answer1” XpathTrigger=“/sml/value” SemanticItem=“siText” runat=“server”> </speech:answer> </Answers> </speech:QA> 2.3 Multimodal App, Do-Field <speech:QA id=“qa1” runat=“server”> <Reco id=“reco1” StartEvent=“dofieldButton.onmousedown” StopEvent=“dofieldButton.onmouseup” mode=“multiple”> <Grammars> <speech:grammar src=“http://mysite/mylargegrammar.xml” runat=“server”> </speech:grammar> </Grammars> </Reco> <Answers> <speech:answer id=“answer1” XpathTrigger=“/sml/value1” SemanticItem=“siOne” runat=“server”> </speech:answer> <speech:answer id=“answer2” XpathTrigger=“/sml/value2” SemanticItem=“siTwo” runat=“server”> </speech:answer> speech:answer id=“answer3” XpathTrigger=“/sml/value3” SemanticItem=“siThree” runat=“server”> </speech:answer> <speech:answer id=“answer4” XpathTrigger=“/sml/value4” SemanticItem=“siFour” runat=“server”> </speech:answer> <speech:answer id=“answer5” XpathTrigger=“/sml/value5” SemanticItem=“siFive” runat=“server”> </speech:answer> </Answers> </speech:QA> 2.4 Voice Only App, Statement <speech:QA id=“welcome” PlayOnce=“true” runat=“server”> <Prompt InLineprompt=“Hello there!”></Prompt> </speech:QA> 2.5 Voice Only App, Simple Question <speech:QA id=“qa1” runat=“server”> <Reco id=“reco1” mode=“automatic”> <Grammars> <speech:grammar src=“http://mysite/citygrammar.grxml” runat=“server”></speech:grammar> </Grammars> </Reco> <Prompt InLinePrompt=“Which city do you want to fly to?”></Prompt> <Answers> <speech:answer id=“answer1” XpathTrigger=“/sml/city” SemanticItem=“siCity” runat=“server”> </speech:answer> </Answers> </speech:QA> 2.6 Voice Only App, Question with Mixed-Initiative (Optional Answers) <speech:QA id=“qa1” runat=“server”> <Reco id=“reco1” mode=“automatic”> <Grammars> <speech:grammar src=“http://mysite/cityANDstate.xml” runat=“server”></speech:grammar> </Grammars> </Reco> <Prompt InLinePrompt=“Which city do you want to fly to?”></Prompt> <Answers> <speech:answer id=“answer1” XpathTrigger=“/sml/city” SemanticItem = “siCity” runat=“server”> </speech:answer> </Answers> <ExtraAnswers> <speech:answer id=“answer2” XpathTrigger=“/sml/state” SemanticItem = “siState” runat=“server”> </speech:answer> </ExtraAnswers> </speech:QA> 2.7 Voice only app, explicit confirmation <speech:QA id=“qa1” runat=“server”> <Reco id=“reco1” mode=“automatic”> <Grammars> <speech:grammar src=“http://mysite/citygrammar.xml” runat=“server”> </speech:grammar> </Grammars> </Reco> <Prompt InLinePrompt=“Which city do you want to fly to?”></Prompt> <Answers> <speech:answer id=“answer1” XpathTrigger=“/sml/city” SemanticItem=“siCity” confirmThreshold=“0.75” runat=“server”> </speech:answer> </Answers> </speech:QA> <speech:QA id=“qa2” runat=“server” xpathAcceptConfirms=“/sml/accept” xpathDenyConfirms=“/sml/deny”> <Prompt InLinePrompt=“Did you say <SALT:value>textbox1.value</SALT:value>”></Prompt> <Reco id=“reco1” mode=“automatic”> <Grammars> <speech:grammar src=“http://mysite/yes_no_city.xml” runat=“server”></speech:grammar> </Grammars> </Reco> <Confirms> <speech:answer id=“answer2” XpathTrigger=“/sml/city” SemanticItem=“siCity” confirmThreshold=“0.75” runat=“server”> </speech:answer> </Confirms> </speech:QA> 2.8 Voice Only App, Short Time-Out Confirmation <speech:QA id=“qa1” runat=“server” xpathAcceptConfirms=“/sml/accept” xpathDenyConfirms=“/sml/deny” firstInitialTimeout=“500”> <Prompt InLinePrompt=“Did you say <SALT:value>textbox1.value</SALT:value>”></Prompt> <Reco id=“reco1” InitialTimeout=“350” mode=“automatic”> <Grammars> <speech:grammar src=“http://mysite/yes_no_city.grxml” runat=“server”></speech:grammar> </Grammars> </Reco> <Confirms> <speech:answer XpathTrigger=“/sml/city” SemanticItem=“siCity” confirmThreshold=“0.75” runat=“server”> </speech:answer> </Confirms> </speech:QA> 2.9 Voice Only App, Commands <speech:QA id=“qa1” runat=“server”> <Prompt id=“prompt1” InLinePrompt=“Where do you want to fly to?”></Prompt> <Reco id=“reco1” mode=“automatic”> <Grammars> <speech:grammar src=“http://mysite/city.grxml” runat=“server”></speech:grammar> </Grammars> </Reco> <Answers> <speech:answer id=“answer1” XpathTrigger=“/sml/city” SemanticItem=“siCity” runat=“server”></speech:answer> </Answers> </speech:QA> <speech:Command id=“command1” type=“cancel” scope=“qa1” OnClientCommand=“myCommand” runat=“server”></speech:Command> <script> function myCommand( ) { CallControl.Hangup( ); } </script> 2.10 Voice Only App, Prompt Selection <speech:QA id=“qa1” runat=“server”> <Prompt id=“prompt1” InLinePrompt=“Where do you want to fly to?”></Prompt> <Reco id=“reco1” mode=“automatic”> <Grammars> <speech:grammar src=“http://mysite/city.grxml” runat=“server”></speech:grammar> </Grammars> </Reco> <Answers> <speech:answer id=“answer1” XpathTrigger=“/sml/city” SemanticItem=“siCity” runat=“server”></speech:answer> </Answers> </speech:QA> <speech:Command id=“command1” type=“cancel” scope=“qa1” OnClientCommand=“myCommand” runat=“server”></speech:Command> <script> function myCommand( ) { CallControl.Hangup( ); } </script> <speech:qa id=“qa1” runat=“server”> <Prompt id=“prompt1” PromptSelectFunction=“promptSelection” /> <Reco id=“reco1” mode=“automatic”> <Grammars> <speech:grammar src=“http://mysite/city.xml” runat=“server”></speech:grammar> </Grammars> </Reco> <Answers> <speech:answer id=“answer1” XpathTrigger=“/sml/city” SemanticItem=“siCity” runat=“server”></speech:answer> </Answers> </speech:qa> <script> function promptSelection (lastCommandOrException, count, answerArray) { if (lastCommandOrException == “Silence”) { return “Sorry, I couldn't hear you. Please speak louder. Where do you want to fly to?”; } else if (count>3) { return “Communication problems are preventing me from hearing the arrival city. Please try again later.”; } return “Where do you want to fly to?”; //Default prompt } } </script> 2.11 Voice Only App, Implicit Confirmation <speech:qa id=“qa1” runat=“server” xpathDenyConfirms=“/sml/deny” xpathAcceptConfirms=“/sml/accept”> <Prompt id=“prompt1” PromptSelectFunction=“promptSelection”></Prompt> <Reco id=“reco1” mode=“automatic”> <Grammars> <speech:grammar src=“http://mysite/yes_no_city.xml” runat=“server”></speech:grammar> </Grammars> </Reco> <Answers> <speech:answer id=“answer1” XpathTrigger=“/sml/date” SemItem=“siDate” runat=“server”></speech:answer> </Answers> <Confirms> <speech:answer id=“confirm1” XpathTrigger=“/sml/city” SemItem=“siCity” runat=“server”></speech:answer> </Confirms> </speech:qa> <script> function promptSelection (lastCommandOrException, count, SemanticItemList) { var myPrompt = “”; if (SemanticItemList[“siCity”].value != null) { myPrompt = “Flying from “ + SemanticItemList[“siCity”].value + “. ”; myPrompt += “On what date?”; } else { myPrompt = “On what date?”; } return myPrompt; } </script> 2.12 Voice Only App, QA with Reco and Dtmf <speech:qa id=“qa1” runat=“server”> <Prompt id=“prompt1” InLinePrompt=“Press or say one if you accept the charges, two if you don't.”></Prompt> <Reco id=“reco1” mode=“automatic”> <Grammars> <speech:grammar src=“http://mysite/acceptCharges.xml” runat=“server”></speech:grammar> </Grammars> </Reco> <Dtmf smlContext=“sml/accept”></Dtmf> <Answers> <speech:answer id=“answer1” XpathTrigger=“/sml/accept” SemanticItem=“siAccept” runat=“server”></speech:answer> </Answers> </speech:qa> 2.13 Voice-Only App, Record-Only QA <speech:qa id=“qa1” runat=“server”> <Answers> <speech:answer id=“a1” XpathTrigger=“/SML/@recordlocation” SemanticItem = “foo” runat=“server”></speech:answer> </Answers> <Reco id=“recordonly”> <record beep=“true”></record> </Reco> </speech:qa></FORM> 3 Design Details 3.1 QA Activation (Voice-Only) QA are tested for activeness in SpeechIndex order (see run-time behavior). A QA is active when clientActivationFunction returns true AND If the Answers array is non empty, the SemanticItems pointed to by the set of Answers are empty OR If the answers array is empty, at least one item in the Confirm array does need confirmation. A QA can have only Answers (normal question: Where do you want to go?), only Confirms (explicit confirmation: Did you say Boston? or short time-out confirmation: Boston.), both (implicit confirmation: When do you want to fly to Boston?) or none (statement: Welcome to my application!). A QA can have extra answers even if it has no answers (e.g., mixed initiative). 3.2 Answer, Confirm. Upon recognition, commands are processed first, followed by Answers, ExtraAnswers and Confirms. A target element (e.g. textbox1.value) can be in one of these states: empty, invalid, needsConfirmation, confirmed. A target is empty before any recognition result is associated with this item, or if the item has been cleared. A target is in needsConfirmation state when a recognition result has been associated with it, but the confidence level is below the confirmationThreshold for this item. And a target is confirmed when either a recognition result has been associated with it with a confidence level high enough or a confirmation loop set it to this state explicitly. Answers are therefore responsible for setting the value in the target element and the confidence level (this is done in a semantic layer). Confirms are responsible for confirming the item, clearing it or setting it to a new value (with a new confidence level). 3.3 Command Execution (and Scope) Commands specify a scope and are active for all QA's within that scope. The default processing of a command is to set the current QA's lastCommandException to the command's type. If the command specifies a Grammar, this grammar is activated in parallel with any grammars in the current Reco object. QAs can be modal (allowCommands=false), in which case, no commands will be processed for that particular QA. 3.4 Validators A CompareValidator will be active when the value of the SemanticItemToValidate it refers to has not been validated by this validator. If SemanticItemToCompare is specified (rather than ValueToCompare), then the CompareValidator will only be active if the value of the SemanticItemToCompare is non-empty (i.e. if it has been assigned a value by a previous QA). A CustomValidator will be active when the value of the SemanticItemToValidate it refers to has not been validated by this validator. 4 Run Time Behavior 4.1 Client Detection The speech controls do pay attention to the variety of client that they are rendering for. If the client doesn't support SALT, the controls won't render any speech-related tags or script. Client detection is done by checking the browser capabilities and detecting whether it's a voice-only client (browser is Quadrant), or multimodal (IE, PocketIE, etc, with SALT support). Hands-free is not a mode in the client, but rather an application-specific modality, and therefore the only support required is SALT (as in multimodal). Hands-free operation is therefore switched-on by application logic. 4.2 Multimodal Support for multimodal applications is built in the speech controls. In multimodal operations commands, dtmf, confirm, prompts, etc do not make sense from an interaction point of view, so they won't be rendered. Tap-and-talk (or any other type of interaction, like click-and-wait-for-recognition) is enabled by hooking up the calls to start and stop recognition with GUI events using the Reco object attributes startElement/startEvent and stopElement/stopEvent, plus the Reco object mode attribute. During render time, the speech controls are passed information specifying whether the client is a voice-only client or multmodal client. If the client is multimodal, the rendering process hooks the call to start recognition to the GUI event specified by the StartEvent attribute of the Reco object. The rendering process also hooks the call to stop recognition to the GUI event specified by the StopEvent attribute of the Reco object. The multimodal client needs a mechanism which will invoke author-specified functions to handle speech-related events (e.g., timeouts) or recognition processing. This mechanism is the Multimodal.js script. Multimodal.js is specified in an external script file and loaded by a single line generated by server-side rendering, e.g., <script language=’”javascript” src=”/scripts/Multimodal.js” /> This method mirrors the ASP.NET way of generating ‘system’ client-side script loaded via URI. Linking to an external script is functionally equivalent to specifying it inline, yet is more efficient since clients are able to cache the file, and cleaner, since the page is not clutered with generic functions. 4.3 Voice-Only 4.3.1 Runtime Script (RunSpeech) Unlike in a multimodal interaction, where the user initiates all speech input by clicking/selecting visual elements in the GUI, a mechanism is needed to provide voice-only clients with the information necessary to properly render speech-enabled ASP.NET pages. Such a mechanism must guarantee the execution of dialog logic and maintain state of user prompting and grammar activation as specified by the author. The mechanism used by the Speech Controls is a client-side script (RunSpeech.js) that relies upon the SpeechIndex attribute of the QA control, plus the flow control mechanisms built in the framework (ClientActivationFunction, default activation rules, etc.). RunSpeech is loaded via URI similar to the loading mechanism of Multimodal.js as described above. 4.3.2 SpeechIndex SpeechIndex is an absolute ordering index within a naming container. If more than one speech control has the same SpeechIndex, they are activated in source order. In situations where some controls have SpeechIndex specified and some controls do not, those with SpeechIndex will be activated first, then the rest in source order. NOTE: Speech index is automatically set to 0 for new controls. Dialog designers should leave room in their numbering scheme to insert new QA's later. Begin with a midrange integer and increment by 100, for example. For example number QA's 1000, 1100, 1200 instead of 1, 2, 3. this leaves room for a large number of QA's at any point the dialog and plenty of room to add QA's at the beginning. 4.3.3 ClientActivationFunction clientActivationFunction specifies a client-side script function which returns a boolean value to determine when this control is considered available for selection by the run-time control selection algorithm. If not specified, it defaults to true (control is active). The system strategy can therefore be changed by using this as a condition to activate or de-activate QAs more sensitively than SpeechIndex. If not specified, the QA is considered available for activation. 4.3.4 Count Count is a property of the QA control that indicates how many times that control has been activated consecutively. This Count property will be reset if the previously active QA is different that the current QA (same applies for Validators), otherwise, it is incremented by one. The Count property is exposed to application developers through the PromptSectionFunction of the Prompt object. Controls Reference General Authoring Notes 1. Script References are not Validated at Render Time. The Speech Controls and objects described in this section contain attributes whose values are references to script functions written by the dialog author. These functions are executed on client devices in response to speech-related events (e.g. expiration of timeout) or as run time processing (e.g. modification of prompt text prior to playback). Render time validation is not performed on script references, i.e., no checks for existence of script functions is done during rendering of controls. If an attribute contains a reference to a client-side script function and the function does not exist, client-side exceptions will be thrown. In voice-only mode, script functions generating exceptions during runtime will cause a redirection to the error page defined in the Web.config file. If no error page is defined, RunSpeech will continue to execute without reporting the exception. 2. All Speech Controls Should be Contained within ASP.NET <form> Tag or Equivalant. The Speech Control described in this section must all be placed in ASP.NET web pages inside the <form> tag. Behavior of controls placed outside the <form> tag is undefined. 3. Client-Side Script References Must Refer to Function and Not Include Parenthes. Using the PromptSelectFunction as an example. the following is correct syntax: <Prompt id=“P1” PromptSelectFunction=“mySelectFunction”/>//using “mySelectFunction( )” is incorrect syntax 4. IE Requires Exact Cases when Running Jscript. Therefore, the case for event values specified in the StartEvent and StopEvent attributes of the Prompt object must be exactly as those events are defined. This happens to be all lowercase letters for most standard IE events. For example, the onmouseup and onmousedown events must be specified in all lowercase letters. 5. All Speech Controls Expose the Common Attribute id. 6. Behavior of Visible and Enabled Properties of Speech Controls. Setting the visible or enabled properies of Speech Controls to “False” will cause them not to render. 7. Mimimum Client Requirements In one embodiment, clients must be running IE6.0 or greater and JScript 5.5 or greater for speech controls and associated script functions to work properly. 8. Rendering <smex> to Telserver The speech controls automatically handle rendering <smex> tags to the telephony server on every page as is required by the server. In one embodiiment, smex tags are rendered whether the client is the tel server or the desktop client. 5 Global Application Settings Speech Controls provide mechanisms that allow dialog authors to specify values to control properties on an application or page basis. 5.1 Application-Level Settings 5.1.1 Application Global Variables Dialog authors may use their application's Web.config file to set values of global variables for speech-enabled web applications. The values of the global variables persist throughout the entrie lifetime of the web application. ‘Errorpage’ is the only global variable that may be specified and is set for the application during render time. <appSettings> <add key=“errorpage” value=“...” /> </appSettings> The <appSettings> tag must be placed one level inside the <configuration> tag within the Web.config file. The errorpage key specifies a URI to a default error page. Redirection to this error page will occur during run time when the speech platform or the DTMF engine returns an error. A default error page is included with the SDK; the user can also create a custom error page. Note: Developers who create their own error page must call window.close at the bottom of the error page in the voice only case in order to release the call. 5.1.2 Application-Level Setting of Common Control Properties Dialog authors may use their application's Web.config file to set values of common control properties and have those values persist during the lifetime of the web application. For example, an author may wish use the Web.config file to set the maxTimeout value for Reco objects in their application. The properties are set in the Web.config file using the following syntax: <configuration> <SpeechStyleSheet> <Style id=”style1” > <QA allowCommands=”false”> ... <Prompt bargein=”false” ... /> <Reco maxTimeout=”5000”... /> <Dtmf preFlush=”true” ... /> <Answers confirmThreshold=”0.80” ... /> <ExtraAnswers confirmThreshold=”0.80” .../> <Confirms confirmThreshold=”0.80”... /> </QA> <Command .../> <CustomValidator .../> <CompareValidator .../> <SemanticItem .../> </Style> </SpeechStyleSheet> </configuration> The Reco corresponding Reco object would reference the “style1” Style: <Reco id=“reco1” . . . StyleReference=“style1” . . . /> If the Style id is “globalStyle,” the property values set in the Style apply application-wide to pertinent controls. So, in the above example, if id=“ ” (or the property is omitted from the Style tag), a maxTimeout of 5000 milliseconds will be used for all Reco objects in the application (uless overridden). For a complete list of properties which are settable through the SpeechStyleSheet, see below. 6 StyleSheet Control The StyleSheet control allows dialog authors to set values to common control properties at a page-level scope. The StyleSheet control is a collection of Style objects. The Style object exposes properties of each control that are settable on a page-level basis. The StyleSheet control is rendered for both multimodal and voice-only modes. An exception will be thrown if the StyleSheet control contains an object which is not a Style object. class StyleSheet : SpeechControl { string id{get; set;}; StyleCollection Styles{get;}; } 6.1 StyleSheet Properties Styles Optional. Used in both multimodal and voice-only modes. The Styles property is a collection of Style objects used to set property values for Speech Controls and their objects. The property values last during the lifetime of the current page. 7 Style Object The Style object is used to set property values for Speech Controls and their objects. The property values last during the lifetime of the current page. class Style : Control { string id{get; set;}; string StyleReference{get; set;}; QAStyle QA{get; set;}; CommandStyle Command{get; set;}; CustomValidatorStyle CustomValidator{get; set;}; CompareValidatorStyle CompareValidator{get; set;}; SemanticItemStyle SemanticItem{get; set;}; } 7.1 Style Properties id Required. The programmatic name of the Style object. StyleReference Optional. Used in both multimodal and voice-only modes. Specifies the name of a Style object. At render time, the StyleSheet control will search for the named Style object and also set property values specified in the named Style. An exception is thrown for an invalid StyleReference. For every property of a speech control with a StyleReference, the value is determined as follows: 1. the value is set directly in the speech control 2. the style object directly referenced 3. any style referenced by a style 4. the global style object 5. the speech control default value. The following example sets shows two QA properties are set using StyleReference: <speech:StyleSheet id=”SS”> <speech:Style id=”base_style” > <QA OnClientActive=”myOnClientActive”/> </speech:Style> <speech:Style id=”derived_style” StyleReference=”base_style”> <QA PlayOnce=”true”/> </speech:Style> </speech:StyleSheet> QA Optional. The QA property of the Style object is used to set property values for all QA controls on a page that reference this Style. The following example shows how to set the AllowCommands and PlayOnce properties for the QA controls that reference this Style: <speech:StyleSheet id=”SS1”> <speech:Style id=”WelcomePageQA_Style” > <QA AllowCommands=”false” PlayOnce=“true”/> </speech:Style> </speech:StyleSheet> <QA id=”...” StyleReference=”WelcomePageQA_Style” .../> The next example shows how to set the bargein property of all Prompt objects on a given page using Params: <speech:StyleSheet id=”SS2”> <Style Name=“Style1”> <QA> <Answers ConfirmThreshold=“0.8” Reject=“0.4”/> <Prompt> <Params> <Param name=“BargeinType” value=“grammar”/> <Param name=“foo” value=“bar” /> <Params> </Prompt> </QA> </Style> </speech: StyleSheet> Command Optional. The Command property of the Style object is used to set property values for all Command controls on a page that reference this Style. CustomValidator Optional. The CustomValidator property of the Style object is used to set property values for all CustomValidator controls on a page that reference this Style. CompareValidator Optional. The CompareValidator property of the Style object is used to set property values for all CompareValidator controls on a page that reference this Style. SemanticItem Optional. The SemanticItem property of the Style object is used to set property values for all SemanticItem controls on a page the reference this Style. The following properties may be set using the Style object. QA Properties AllowCommands PlayOnce XpathAcceptConfirms XpathDenyConfirms AcceptRejectThreshold DenyRejectThreshold FirstInitialTimeout ConfirmByOmission ConfirmIfEqual OnClientActive OnClientListening OnClientComplete. Prompt Properties These apply to Prompts in QA, CompareValidator, CustomValidator and Command controls. Bargein OnClientBookmark OnClientError Prefetch Type Lang Params Reco Properties StartEvent StopEvent Mode InitialTimeout BabbleTimeout MaxTimeout EndSilence Reject OnClientSpeechDetected OnClientSilence OnClientNoReco OnClientError Lang Params Grammar Properties These apply to both Reco and Dtmf grammars. Type Lang Dtmf Properties InitialTimeout InterDigitTimeout OnClientSilence OnClientKeyPress OnClientError Params Answer Properties These apply to the Answers, ExtraAnswers and Confirms collections. ConfirmThreshold Reject Command Properties Scope AcceptCommandThreshold CompareValidator Properties ValidationEvent Operator Type InvalidateBoth CustomValidator Properties ValidationEvent SemanticItem Properties BindOnChange 8 QA Control The QA control is responsible for querying the user with a prompt, starting a corresponding recognition object and processing recognition results. The QA control is rendered for both multimodal and voice-only modes. class QA : IndexedStyleReferenceSpeechControl { string id{get; set;}; int SpeechIndex{get; set;}; string ClientActivationFunction{get; set;}; string OnClientActive{get; set;}; string OnClientComplete{get; set;}; string OnClientListening{get; set;}; bool AllowCommands{get; set;}; bool PlayOnce{get; set;}; string XpathAcceptConfirms{get; set;}; string XpathDenyConfirms{get; set;}; float AcceptRejectThreshold{get; set;}; float DenyRejectThreshold{get; set;}; float FirstInitialTimeout{get; set;}; string StyleReference{get; set;}; bool ConfirmByOmission{get; set;}; bool ConfirmIfEqual{get; set;}; AnswerCollection Answers{get;}; AnswerCollection ExtraAnswers{get;}; AnswerCollection Confirms{get;}; Prompt Prompt{get;}; Reco Reco{get;}; Dtmf Dtmf{get;}; }. 8.1 QA Properties All properties of the QA control are available to the application developer at design time. SpeechIndex Optional. Default is Zero, which is equivalent to no SpeechIndex. Only used in voice-only mode. Specifies the activation order of speech controls on a page and the activation order of composite controls. All controls with SpeechIndex >0 will be run and then controls with SpeechIndex=0 will be run in source order. If more than one control has the same SpeechIndex, they are activated in source order. In situations where some controls specify SpeechIndex and some controls do not, those with SpeechIndex specified will be activated first, then the rest in source order. SpeechIndex values start at 1. An exception will be thrown for non-valid values of SpeechIndex. ClientActivationFunction Optional. Only used in voice-only mode. Specifies a client-side script function which returns a Boolean value to determine when a QA control is considered available for selection by the run-time control selection algorithm. If not specified, it defaults to true (control is active). The signature for ClientActivationFunction is as follows: bool ClientActivationFunction (object lastActiveObj, string lastCommandOrException, int count) where: lastActiveObj is the last active control, e.g. QA, CustomValidator or CompareValidator. For the first activated QA on a page, lastActiveObj will be null. lastCommandOrException is a Command type (e.g., “Help”) or a Reco event (e.g., “Silence” or “NoReco”) of the last active control. For the first activated QA on a page or if the last active control is a validator, lastCommandOrException will be an empty string. count number of times the last active QA has been activated consecutively, 1 if this is the first acvtive QA on the page. Count starts at 1 and has no limit. However, for the first activated QA on a page, count will be set to zero. OnClientActive Optional. Used in both multimodal and voice-only modes. Specifies a client-side script that will be called after RunSpeech determines this QA is active (voice-only mode) or after the startEvent is fired (in multimodal) and before processing the QA (e.g., playing a prompt or starting recognition). The onClientActive function does not return values. The signature for onClientActive is as follows: function onClientActive(string eventsource, string lastCommandOrException, int Count, object SemanticItemList) where: eventsource is the id of the object (specified by Reco.StartEvent) whose event started the Reco associated with the QA (for multimodal). eventsource will be null in voice-only mode. lastCommandOrException is a Command type (e.g., “Help”) or a Reco event (e.g., “Silence” or “NoReco”) for voice-only mode. lastCommandOrException is the empty string for multimodal. Count is the number of times the QA has been activated consecutively. Count starts at 1 and has no limit for voice-only mode. Count is zero for multimodal. SemanticItemList For voice-only mode, SemanticItemList is an associative array that maps semantic item id to semantic item objects. For multimodal, SemanticItemList will be null. OnClientComplete Optional. Used in both multimodal and voice-only modes. Specifies a client-side script that will be called after execution of a QA (successfully or not) and before passing dialog control back to the RunSpeech algorithm (in voice-only) or the end user (in multimodal). The OnClientComplete function is called before postbacks to the server for QAs whose AutoPostBack attribute of the Answer object is set to true. The onClientComplete function does not return values. The signature for onClientComplete is as follows: function onClientComplete (string eventsource, string lastCommandOrException, int Count, object SemanticItemList) where: eventsource is the id of the object (specified by Reco.StopEvent) whose event stopped the Reco associated with the QA (for multimodal). eventsource will be null in voice-only mode. lastCommandOrException is a Command type (e.g., “Help”) or a Reco event (e.g., “Silence” or “NoReco”) for voice-only mode. lastCommandOrException is the empty string for multimodal. Count is the number of times the QA has been activated consecutively. Count starts at 1 and has no limit for voice-only mode. Count is zero for multimodal. SemanticItemList For voice-only mode, SemanticItemList is an associative array that maps semantic item id to semantic item objects. For multimodal, SemanticItemList will be null. OnClientListening Optional. Used in both multimodal and voice-only modes. Specifies a client-side script (function) that will be called/executed after successful start of the reco object. The main use is so the GUI can change to show the user that they can start speaking. The function does not return any values. The signature for OnClientListening is as follows: function onClientListening(string eventsource, string lastCommandOrException, int Count, object SemanticItemList) where: eventsource is the id of the object (specified by Reco.StartEvent) whose event started the Reco associated with the QA (for multimodal). eventsource will be null in voice-only mode. lastCommandOrException is a Command type (e.g., “Help”) or a Reco event (e.g., “Silence” or “NoReco”) for voice-only mode. lastCommandOrException is the empty string for multimodal. Count is the number of times the QA has been activated consecutively. Count starts at 1 and has no limit for voice-only mode. Count is zero for multimodal. SemanticItemList For voice-only mode, SemanticItemList is an associative array that maps semantic item id to semantic item objects. For multimodal, SemanticItemList will be null. Note: In multimodal mode OnClientListening is only available if author chooses to use StartEvent. If author decides to start reco programmatically, then onClientListening is not called for the author because the author can detect when reco.start returns successfully. Note: OnClientListening is ignored when specified in QA's that do not contain reco objects. AllowCommands Optional. Only used in voice-only mode. Indicates whether or not Commands may be activated for a QA control. When AllowCommands is set to false, no commands may be activated. Defaults to true. PlayOnce Optional. Only used in voice-only mode. Specifies whether or not a QA may be activated more than once per page. If not specified, PlayOnce is set to false. PlayOnce=“true” may be used to author statements like welcoming prompts. When a QA is reduced to a statement (no reco), setting PlayOnce=“false” will provide dialog authors with the capability to enable a “repeat” functionality on a page that reads email messages. XpathAcceptConfirms Optional. Only used in voice-only mode. Specifies the path in the sml document (recognition result) that indicates the confirm items were accepted. Required if Confirms are specified. If XpathAcceptConfirms is specified without a Confirm being specified it is ignored. XpathAcceptConfirms must be a valid xml path. An invalid xml path will cause a redirection to the default error page during run time. XpathDenyConfirms Optional. Used only in voice-only mode. Specifies the path in the sml document that indicates the confirm items were denied. Required if Confirms are specified. If a Confirm is specified and XpathDenyConfirms is not set an exception is thrown. If XpathDenyConfirms is specified without a Confirm being specified it is ignored. XpathDenyConfirms must be a valid xml path. An invalid xml path will cause a redirection to the default error page during run time. AcceptRejectThreshold Optional. Used only in voice-only mode. If confidence for an accept confirm is not above this threshold no action will be taken. Legal values are 0-1 and are platform specific. An exception will be thrown for out of range AcceptRejectThreshold values. Default is zero. DenyRejectThreshold Optional. Used only in voice-only mode. If confidence for a deny confirm is not above this threshold no action will be taken. Legal values are 0-1 and are platform specific. An exception will be thrown for out of range DenyRejectThreshold values. Default is zero. FirstInitialTimeout Optional. Only used in voice-only mode. Specifies the initial timeout in msec for the QA when count==1. The status of the TargetElements specified in the Confirms answer list will be set to “Confirmed” if no speech is detected within firstInitialTimeout milliseconds. If not specified the default value of firstInitialTimeout is 0, which means that silence does not imply confirmation of the Answer. An exception will be thrown if firstInitialTimeout is specified for a QA that does not contain Confirms. An exception will be thrown for negative values of FirstInitialTimeout. StyleReference Optional. Used in both multimodal and voice-only modes. Specifies the name of a Style object. At render time, the QA control will search for the named Style control and will use any property values specified on the Style as default values for its own properties. Explicitly set property values on the control will override those set on the Style. ConfirmByOmission Optional. Used only in voice-only mode. Default is true. This flag controls confirmation of more than one item. If the flag is set to true, then any semantic items whose xpath is not present in the reco result, will be set to Confirmed. ConfirmByOmission enables the following scenario: (ConfirmByOmission=true) Q: Flying from? A: Boston. Q: Flying to? A: Seattle. Q: From Boston to Seattle? A: From NY. (Seattle is confirmed as destination city). ConfirmIfEqual Optional. Used only in voice-only mode. Default is true. This flag controls the processing of corrections during confirmation. If ConfirmIfEqual is true and a recognized correction is the same value already in the semantic item, the item is maked confirmed. If ConfirmIfEqual is false and a recognized correction is the same value already in the semantic item, the item is maked as needing confirmation. Answers Optional. An array of answer objects. This list of objects is used both to determine activation, and to carry out semantic processing logic. An exception will be thrown if an Answers collection contains non-answer objects. ExtraAnswers Optional. An array of answer objects. These items are not used for activation, but they are taken into account when processing recognition results. If an ExtraAnswer is recognized, it will overwrite the semantic item it points to, even if it was previously confirmed. Confirms Optional. An array of answer objects. These items are used for activation if the answers array is empty.and they affect the confirmation logic. Prompt Optional for multimodal. Required for voice-only. An exception is thrown if a Prompt is not specified in voice-only mode. Reco Optional for multimodal and voice-only. Typically, only one reco can be specified in a QA. Dtmf Optional. Only used in voice-only mode. Typically, only one Dtmf can be specified in a QA. 9 Command Control The Command control provides a way for obtaining user input that is not an answer to the question at hand (eg, Help, Repeat, Cancel), and which does not map to textual input into primary controls. A Command specifies an activation scope, which means that its grammar is active (in parallel with the current recognition grammar) for every QA within that scope. Commands have a type attribute which is used to implement a chain of events: Commands of the same type at QAs lower in scope can override superior commands with context-sensitive behavior (and even different/extended grammars if necessary) and to notify the QA what command was uttered (via the reason parameter). Commands are not rendered for multimodal mode. class Command : SpeechControl { string id{get; set;}; string Scope{get; set;}; string Type{get; set;}; string XpathTrigger{get; set;}; float AcceptCommandThreshold{get; set;}; string OnClientCommand{get; set;}; bool AutoPostBack{get; set;}; TriggeredEventHandler OnTriggered; string StyleReference{get; set;}; Prompt Prompt{get;}; Grammar Grammar{get;}; Grammar DtmfGrammar{get;}; } 9.1 Command Properties All properties of the Command control are available to the application developer at design time. Scope Required. Only used in voice-only mode. Specifies the id of a QA or other ASP.NET control (e.g., form, panel, or table). Scope is used in Commands to specify when the Command's grammars will be active. Exceptions are thrown if Scope is invalid or not specified. Type Required. Only used in voice-only mode. Specifies the type of command (eg ‘help’, ‘cancel’ etc.) in order to allow the overriding of identically typed commands at lower levels of the scope tree. Any string value is possible in this attribute, so it is up to the author to ensure that types are used correctly. An exception is thrown if Type is not specified. Note: An exception will be thrown if more than 1 Command of same Type has the same Scope. For example, 2 Type=“Help” Commands for the same QA (Scope=“QA1”). AcceptCommandThreshold Optional. Only used in voice-only mode. Specifies the minimum confidence level of recognition that is necessary to trigger the command (this is likely to be used when higher than usual confidence is required, e.g. before executing the result of a ‘Cancel’ command). Legal values are 0-1. Default value is 0. Exceptions will be thrown for out of range AcceptCommandThreshold values. If a command is matched (its xpathTrigger is present in the recoResult) no further commands will be processed, and no Answers, ExtraAnswers, Confirms, etc. will be processed. Then, if the confidence of the node specified by XpathTrigger is greater than or equal to the acceptThreshold, the active QAs LastCommandOrException is set to the Command's type, and the Command's onCommand function is called. Otherwise (if the confidence of the node is less than the acceptThreshold) the active QAs LastCommandOrException is set to “NoReco” and the active QAs Reco's OnClientNoReco function is called. XpathTrigger Required. Only used in voice-only mode. SML document path that triggers this command. An exception will be thrown if XpathTrigger is not specified. XpathTrigger must be a valid xml path. An invalid xml path will cause a redirection to the default error page during run time. OnClientCommand Optional. Only used voice-only mode. Specifies the client-side script function to execute on recognition of the Command's grammar. The function does not return any values. The signature for OnClientCommand is as follows: function OnClientCommand(XMLNode smlNode) where: smlNode is the matched SML node. Note: If AutoPostBack is set to true, the OnClientCommand function is executed before posting back to the server. If the author wishes to persist any page state across postback, the OnClientCommand function is a good place to invoke the ClientViewState object of RunSpeech. AutoPostBack Optional. Only used in voice-only mode. Specifies whether or not the Command control posts back to the server each time a Command grammar is recognized. Default is false. If set to true, the server-side Triggered event is fired. The internal state of the voice-only page is maintained automatically during postback. Authors may use the ClientViewState object of RunSpeech to declare and set additional values they wish to persist across postbacks. OnTriggered Optional. Only used in voice-only mode. Specifies a server-side script function to be executed when the Triggered event is fired (see autopostback attribute above). This handler must have the form (in C#—the signature would look slightly different in other languages): void myFunction (object sender, CommandTriggeredEventArgs e); The handler can be assigned to in two different ways—declaratively: <speech:Command . . . OnTriggered=“myFunction” . . . /> or programmatically: Command.Triggered +=new TriggeredEventHandler(myFunction); TriggeredEventHandler is what is called a “delegate”—it basically specifies the signature of functions which can handle its associated event type. It looks like this: public delegate void TriggeredEventHandler(object sender, TriggeredEventArgs e); where: TriggeredEventArgs is a class derived from System.EventArgs which contains one public property, string Value. An exception will be thrown if AutoPostBack is set to true and no handler is specified for the Triggered event. An exception will be thrown if AutoPostBack is set to false and a handler is specified for the Triggered event. StyleReference Optional. Only used in voice-only mode. Specifies the name of a Style object. At render time, the QA control will search for the named Style control and will use any property values specified on the Style as default values for its own properties. Explicitly set property values on the control will override those set on the Style. Prompt Optional. May be used to specify prompt to be played for global commands. Grammar Optional. The grammar object which will listen for the command. Note: The grammar object is optional because the QA scoped by this command may contain the rule that generates this command's Xpath. The author has the flexibility of specifying the rule in the QA control or the Command control. DtmfGrammar Optional. The DtmfGrammar object which will activate the command. Available at run time. Note: The DtmfGrammar object is optional because the QA scoped by this command may contain the rule that generates this command's Xpath. The author has the flexibility of specifying the rule in the QA control or the Command control. DtmfGrammars for all Commands along the QA's scope chain will be combined into the Grammars collection for the QA's Dtmf object. Speech Controls does not provide a set of common commands—e.g., help, cancel, repeat. 10 CompareValidator Control This control compares two values, applying the operator, and if the comparison is false, invalidates the item specified by SemanticItemToValidate. Optionally, both items (ToCompare and ToValidate) are invalidated. The CompareValidator is triggered on the client by change or confirm events; however, validation prompts are played in SpeechIndex order. The CompareValidator control is rendered for voice-only mode. For multimodal, ASP.NET validator controls may be used. class CompareValidator : IndexedStyleReferenceSpeechControl { string id{get; set;}; int SpeechIndex{get; set;}; ValidationType Type{get; set;}; string ValidationEvent{get; set;}; string SemanticItemToCompare{get; set;}; string ValueToCompare{get; set;}; string SemanticItemToValidate{get; set;}; ValidationCompareOperator Operator{get; set;}; bool InvalidateBoth{get; set;}; string StyleReference{get; set;}; Prompt Prompt{get;}; } 10.1 CompareValidator Properties All properties of the CompareValidator control are only used in voice-only mode and are available to the application developer at design time. SpeechIndex Optional. Specifies the activation order of CompareValidator controls on a page. If more than one control has the same SpeechIndex, they are activated in source order. In situations where some controls specify SpeechIndex and some controls do not, those with SpeechIndex specified will be activated first, then the rest in source order. SpeechIndex values start at 1. An exception will be thrown for non-valid values of SpeechIndex. Type Required. Sets the datatype of the comparison. Legal values are “String”, “Integer”, “Double”, “Date”, and “Currency”. Default value is “String”. ValidationEvent Default is “onconfirmed”. ValidationEvent may be set to one of two values, either “onchange” or “onconfirmed”. If ValidationEvent is set to “onchanged”, the CompareValidator will be run each time the value of the Text property of the associated SemanticItem changes. The CompareValidator control will be run before the SemanticItem's OnChanged handler is called. The SemanticItem's OnChanged handler will only be called if the CompareValidator does indeed validate the changed data. If the CompareValidator invalidates the data, the State of the SemanticItem is set to Empty and the OnChanged handler is not called. If ValidationEvent is set to “onconfirmed”, the CompareValidator will be run each time the State of the associated SemanticItem changes to Confirmed. The CompareValidator control will be run before the SemanticItem's OnConfimed handler is called. The SemanticItem's OnConfirmed handler will only be called if the CompareValidator does indeed validate the changed data. If the CompareValidator invalidates the data, the State of the SemanticItem is set to Empty and the OnConfirmed handler is not called. After processing all SemanticItems involved a recognition turn, RunSpeech starts again. At that point, the previously failed validators will be active and RunSpeech will select the first QA/Validator that is active in SpeechIndex order. It is the author's responsibility to place the validator controls directly before the QA control that collects the answer for the SemanticItem in order to get the correct behavior. SemanticItemToCompare Optional. Either SemanticItemToCompare or ValueToCompare must be specified. Specifies the Id of the SemanticItem which will be used as the basis for the comparison. Available at design time and run time. An exception will be thrown if either SemanticItemToCompare or ValueToCompare is not specified. ValueToCompare Optional. Either SemanticItemToCompare or ValueToCompare must be specified. Specifies the value to be used as the basis for the comparison. The author may wish to specify the value here instead of taking the value from the semantic item. If both ValueToCompare and SemanticItemToCompare are set, SemanticItemToCompare takes precedence. An exception will be thrown if either SemanticItemToCompare or ValueToCompare is not specified. An exception will be thrown if ValueToCompare can not be converted to a valid Type. SemanticItemToValidate Required. Specifies the Id of the SemanticItem that is being validated against either ValueToCompare or SemanticItemToCompare. An exception will be thrown for unspecified SemanticItemToValidate. Operator Optional. One of “Equal”, “NotEqual”, “GreaterThan”, GreaterThanEqual”, “LesserThan”, “LesserThanEqual”,“DataTypeCheck”. Default value is “Equal”. The values are compared in the following order: Value to Validate [operator] ValueToCompare. InvalidateBoth Optional. If true, both SemanticItemToCompare and SemanticItemToValidate are marked Empty. Default is false (i.e., invalidate only the SemanticItemtToInvalidate). If SemanticItemToValidate has not been set (i.e. ValueToCompare has been specified), InvalidateBoth is ignored. The following example illustrates the usage of the InvalidateBoth attribute. The scenario is an itinerary application. The user has already been prompted and answered the question for departing city. At this point in the dialog an ASP.NET textbox control has been filled with the recognition results (assume txtDepartureCity.Value=“Austin”). The next QA prompts the user for the arrival city, the SemanticItem object binds to txtArrivalCity.Value. In response to the prompt, the user says “Boston”. However, the recognition engine returns “Austin” (e.g. arrival city is same as departing city). The CompareValidator control may be used to direct the dialog flow in this case to re-prompt the user for both departing and arriving cities: <CompareValidator id=”compareCities” SpeechIndex=”5” Type=”String” SemanticItemToCompare=”si_DepartureCity” SemanticItemToValidate=”si_ArrvivalCity” Operator=”NotEqual” InvalidateBoth=”True” runat=”server” </CompareValidator> StyleReference Optional. Specifies the name of a Style object. At render time, the QA control will search for the named Style control and will use any property values specified on the Style as default values for its own properties. Explicitly set property values on the CompareValidator control will override those set on the Style. Prompt Optional. Prompt to indicate the error. 11 CustomValidator Control The CustomValidator control is used to validate recognition results when complex validation algorithms are required. The control allows dialog authors to specify their own validation routines. The CustomValidator is triggered on the client by change or confirm events; however, validation prompts are played in SpeechIndex order. The CustomValidator control is only rendered for voice-only mode. For multimodal, ASP.NET validator controls may be used. class CustomValidator : IndexedStyleReferenceSpeechControl { string id{get; set;}; int SpeechIndex{get; set;}; string ValidationEvent{get; set;}; string SemanticItemToValidate{get; set;}; string ClientValidationFunction{get; set;}; string StyleReference{get; set;}; Prompt Prompt{get;}; } 11.1 CustomValidator Properties All properties of the CustomValidator control are only used in voice-only mode and are available to the application developer at design time. SpeechIndex Optional. Only used in voice-only mode. Specifies the activation order of speech controls on a page and the activation order of composite controls. If more than one control has the same SpeechIndex, they are activated in source order. In situations where some controls specify SpeechIndex and some controls do not, those with SpeechIndex specified will be activated first, then the rest in source order. SpeechIndex values start at 1. An exception will be thrown for non-valid values of SpeechIndex. ValidationEvent Default is “onconfirmed”. ValidationEvent may be set to one of two values, either “onchange” or “onconfirmed”. If ValidationEvent is set to “onchanged”, the CustomValidator will be run each time the value of the Text property of the associated SemanticItem changes. The CustomValidator control will be run before the SemanticItem's OnChanged handler is called. The SemanticItem's OnChanged handler will only be called if the CustomValidator does indeed validate the changed data. If the CustomValidator invalidates the data, the State of the SemanticItem is set to Empty and the OnChanged handler is not called. If ValidationEvent is set to “onconfirmed”, the CustomValidator will be run each time the State of the associated SemanticItem changes to Confirmed. The CustomValidator control will be run before the SemanticItem's OnConfimed handler is called. The SemanticItem's OnConfirmed handler will only be called if the CustomValidator does indeed validate the changed data. If the CustomValidator invalidates the data, the State of the SemanticItem is set to Empty and the OnConfirmed handler is not called. After processing all SemanticItems involved a recognition turn, RunSpeech starts again. At that point, the previously failed validators will be active and RunSpeech will select the first QA/Validator that is active in SpeechIndex order. It is the author's responsibility to place the validator controls directly before the QA control that collects the answer for the SemanticItem in order to get the correct behavior. SemanticItemToValidate Required. Specifies the id of the SemanticItem that is being validated. An exception will be thrown for unspecified SemanticItem ToValidate. ClientValidationFunction Required. Specifies a function that checks the value of the SemanticItemToValidate.AttributeToValidate and returns true or false indicating whether the value is valid or invalid. The signature for ClientValidationFunction is as follows: bool ClientValidationFunction (string value) where: value is the contents of ElementToValidate.AttributeToValidate. An exception will be thrown if ClientValidationFunction is not specified. StyleReference Optional. Specifies the name of a Style object. At render time, the QA control will search for the named Style control and will use any property values specified on the Style as default values for its own properties. Explicitly set property values on the control will override those set on the Style. Prompt Optional. Prompt to indicate the error. 12 Answer Object The Answer object contains information on how to process recognition results and bind the results to controls on an ASP.NET page. How Answer object is used. Voice-only mode. The RunSpeech script uses the Answer object to perform answer processing on the client. Answer processing begins when the OnReco event fired by the speech platform is received by the client. The resultant SML document returned by the speech platform is searched for the node specified by the required XpathTrigger attribute. If the XpathTrigger node is found in the SML document and contains a non-null value, the value is is filled into the semantic item specified in the SemanticItem property of the answer. For non-existant XpathTrigger in the SML document or null value of XpathTrigger, RunSpeech looks for the next QA to activate. After the non-null value of the XpathTrigger node is found, RunSpeech invokes the ClientNormalization function (if specified). The ClientNormalizationFunction returns a text string that reflects the author-defined transformation of the value of the XpathTrigger node. For example, the author may wish to transform the date “Nov. 17, 2001” returned by the speech platform to “Nov. 17, 2001”. Semantic items are used for both simple and complex data binding. The SML document returned by the speech platform may contain a platform-specific confidence rating for each XpathTrigger node. During answer processing, RunSpeech compares this confidence rating to the value specified in the ConfirmThreshold attribute of the Answer object. Results of the comparison are then used to set the internal confirmed state of the semantic item. This state information is subsequently used to determine whether or not an answer requires confirmation from the user. RunSpeech internally marks an answer as needing confirmation if the confidence returned with the XpathTrigger is less than or equal to the value of the ConfirmThreshold attribute. Otherwise RunSpeech internally marks the semantic item associated with the answer as confirmed. This internal state information is used during confirmation processing. Multimodal. The Answer object is used in multimodal scenarios by the Multimodal.js script just as it is used by RunSpeech in voice-only (described above) with one exception. In multimodal, platform-specific confidence ratings are not compared to the ConfirmThreshold attribute of the Answer object, therefore internal state information of each answer is not maintained. Confirmation of results is done visually. If an incorrect result is bound to a visual control, the user senses the problem visually and may then initiate another speech input action to correct the error. Rendered for both multimodal and voice-only modes class Answer : Control { string id{get; set;}; float Reject{get; set;}; float ConfirmThreshold{get; set;}; string XpathTrigger{get; set;}; string SemanticItem{get; set;}; string ClientNormalizationFunction{get; set;}; string StyleReference{get; set;}; } 12.1 Answer Properties All properties of the Answer object are available to the application developer at design time. Reject Optional. Used in both multimodal and voice-only modes. Specifies the rejection threshold for the Answer. Answers having confidence values below Reject will cause a noReco event to be thrown. If not specified, the value 0 will be used. Legal values are 0-1 and are platform specific. An exception will be thrown for out of range Reject values. Rejected Answers are treated as if they were not present in the reco result to begin with. If, after this processing, no relevant information remains (no Answers, ExtraAnswers, Confirms, Commands, or xpathAcceptConfirms/xpathDenyConfirms), an onnoreco event is fired (which mimics exactly the tags version). ConfirmThreshold Optional. Used in voice-only mode. Specifies the minimum confidence level of recognition that is necessary to mark this item as confirmed. If the confidence of the matched item is less than or equal to this threshold, the item is marked as needing confirmation. Legal values are 0-1. Default value is 0. An exception will be thrown for out of range ConfirmThreshold values. XpathTrigger Required for Answers and ExtraAnswers. Optional for Confirms. Used in both multimodal and voice-only modes. Specifies what part of the SML document this answer refers to. It is specified as an XPath on the SML output from recognition. An exception will be thrown if XpathTrigger is not specified for Answers or ExtraAnswers. XpathTrigger must be a valid xml path. An invalid xml path will cause a redirection to the default error page during run time. For Confirms, if XpathTrigger is not set or set to the empty string, the confirm won't allow for correction. Yes/no confirmations are enabled when XpathTrigger is used in this way. SemanticItem Optional. Used in both multimodal and voice-only modes. ClientNormalizationFunction Optional. Used in both multimodal and voice-only modes. Specifies a client-side function that will take the matched sml node as a parameter and returns a string that reflects author-specified normalization (transformation) of the recognized item. The signature for ClientNormalizationFunction is as follows: string ClientNormalizationFunction(XMLNode SMLnode, object SemanticItem) where: SMLnode is the node specified in the Xpath. SemanticItem is the client-side SemanticItem object specified in the Answer object. StyleReference Optional. Used in both multimodal and voice-only modes. Specifies the name of a Style object. At render time, the Answer object will search for the named Style control and will use any property values specified on the Style as default values for its own properties. Explicitly set property values by the Answer object will override those set on the referenced Style. 13 SemanticMap Control SemanticMap is a container of SemanticItem objects. class SemanticMap : SpeechControl { SemanticItemCollection SemItems{get;}; SemanticItem GetSemanticItem (string name); } 13.1 SemanticMap Properties SemItems A collection of SemanticItem objects. 13.2 SemanticMap Methods GetSemanticItem This is a function that takes the id of a SemanticItem and returns the SemanticItem object. The signature of GetSemanticItem is: function GetSemanticItem(string id) 14 SemanticItem Object The SemanticItem object describes where and when an Answer's recognition results are written to visual controls on a page. The object also keeps track of the current state of Answers, i.e., whether an Answer has changed or been confirmed. class SemanticItem : Control { string id{get; set;}; string TargetElement{get; set;}; string TargetAttribute{get; set;}; bool BindOnChanged{get; set;}; string BindAt{get; set;}; bool AutoPostBack{get; set;}; string OnClientChanged{get; set;}; string OnClientConfirmed{get; set;}; SemanticEventHandler Changed; SemanticEventHandler Confirmed; string Text{get;}; SemanticState State{get;}; StringDictionary Attributes{get; set;}; string StyleReference{get;}; } 14.1 SemanticItem Properties id Required. The programmatic id of this semantic item. TargetElement Optional. Used in both multimodal and voice-only modes. Specifies the id of the visual control to which the recognition results should be written. If specified, default binding will occur when the value is changed or confirmed depending on the value of BindOnChanged. An exception is thrown if TargetElement is the id of multiple controls. TargetAttribute Optional. Used in both mutimodal and voice-only modes. Specifies the property name of the TargetElement to which this answer should be written. The default value is null. An exception will be thrown if TargetElement is specified and TargetAttribute is not specified. BindOnChanged Optional. Used voice-only mode, ignored in multimodal. Default is false. In VoiceOnly mode, BindOnChanged controls when to bind recognition results to visual elements. A value of true causes binding everytime the value of the SemanticItem changes. A value of false causes binding only when the SemanticItem has been confirmed. BindAt Optional. Used in both mutimodal and voice-only modes. Can be omitted or set to “server”. Default is null (omitted). If BindAt is set to “server”, it indicates that the TargetElement/TargetAttribute pair refers to a server-side control or property. An exception will be thrown when BindAt is set to an invalid value. If BindAt is “server”, an exception will be thrown if: SemanticItem.TargetElement is not a server-side control, or SemanticItem.TargetAttribute is not a member of the control specified by SemanticItem.TargetElement, or SemanticItem.TargetAttribute is a member of SemanticItem.TargetElement, but is not of type string, or SemanticItem.TargetAttribute is a string, but is read-only. AutoPostBack Optional. Used in both multimodal and voice-only modes. Specifies whether or not the control posts back to the server when the binding event is fired. The binding event can be onChanged or onConfirmed and is controlled by the value of BindOnChange. Default is false. The state of the voice-only page is maintained automatically during postback. Authors may use the ClientViewState object of RunSpeech to declare and set any additional values they wish to persist across postbacks. OnClientChanged Optional. Used in both multimodal and voice-only modes. Specifies a client-side function to be called when the value of the Text property of this SemanticItem changes. The function does not return any values. The signature for OnClientChanged is as follows: function OnClientChanged(object SemanticItem) where SemanticItem is the client-side SemanticItem object. Note: If AutoPostBack is set to true, the OnClientChanged function is executed before posting back to the server. If the author wishes to persist any page state across postback, the OnClientChanged function is a good place to access the ClientViewState object of RunSpeech. OnClientConfirmed Optional. Used in both multimodal and voice-only modes. Specifies a client-side function to be called when this SemanticItem's [value is confirmed. The function does not return any values. The signature for OnClientConfirmed is as follows: function OnClientConfirmed(object SemanticItem) where SemanticItem is the client-side SemanticItem object. Note: If AutoPostBack is set to true, the OnClientConfirmed function is executed before posting back to the server. If the author wishes to persist any page state across postback, the OnClientConfirmed function is a good place to access the ClientViewState object of RunSpeech. Changed Optional. Used in both multimodal and voice-only modes. Specifies a server-side script function to be executed when the Changed event is fired. The signature of a SemanticEventHandler is: (in C#—the signature would look slightly different in other languages) public delegate void SemanticEventHandler (object sender, SemanticEventArgs e where: SemanticEventArgs is a class derived from System.EventArgs. public class SemanticEventArgs : EventArgs { public string Text {get;}; public StringDictionary Attributes {get;} } Text Returns the value that this SemanticItem has been set to. State Returns the state of this SemanticItem. Confirmed Optional. Used in both multimodal and voice-only modes. Specifies a server-side script function to be executed when the Confirmed event is fired. In multimodal mode, the Confirmed event will be fired immediately after the Changed event. The signature of a SemanticEventHandler is: (in C#—the signature would look slightly different in other languages) public delegate void SemanticEventHandler (object sender, SemanticEventArgs e); where: SemanticEventArgs is a class derived from System.EventArgs. public class SemanticEventArgs : EventArgs { public string Text {get;} public StringDictionary Attributes {get;} } Text Read only. Returns the value that this SemanticItem has been set to. State Read only. Returns the state of this SemanticItem. Text The text value that this SemanticItem has been set to. Default is null. State The confirmation state of this SemanticItem. Values of State will be one of SemanticState.Empty, SemanticState.NeedsConfirmation or SemanticState.Confirmed. Attributes Optional. Used in both multimodal and voice-only modes. This is a collection of name/value pairs. Attributes is used to pass user defined information to the client-side semantic item and back to the server (they are kept synchronized). Attributes may only be set programmatically. For example: SemanticItem.Attributes [“myvarname”]=“myvarvalue” Attributes are not cleared when the SemanticItem is reset by the system. If developers wish to reset the attributes, they must do so manually. StyleReference Optional. Used in both multimodal and voice-only modes. Specifies the name of a Style object. At render time, the QA SemanticItem object will search for the named Style control and will use any property values specified on the Style as default values for its own properties. Explicitly set property values by the SemanticItem object will override those set on the referenced Style. 14.2 SemanticItem Client-Side Object //Notation doesn't imply programming language class SemanticItem { SemanticItem (sco, id, targetElement, targetAttribute, bindOnChanged, bindAtServer, autoPostback, onClientChanged, onClientConfirmed, hiddenFieldID, value, state); SetText (string text, boolean isConfirmed); Confirm( ); Clear( ); Empty( ); AddValidator (validator); IsEmpty( ); NeedsConfirmation( ); IsConfirmed( ); Encode( ); Object value; //Read only string state; //Read only object attributes; } SetText (string text, boolean isConfirmed) The SetText method of the client side semantic item object is used to alter the value property. The partmeters are string text the string which will become the value of the the Semantic Item Boolean isConfirmed determines whether the Semantic Item state property is “confirmed” (if true) or “needs confirmation” if false Confirm( ) This method sets the state property of the Semantic Item property to “confirmed.” Clear( ) This method sets the value property of the Semantic Item to NULL and sets the state property to “empty.” Empty( ) AddValidator (validator) IsEmpty( ) This method checks to see if the state property of the Semantic Item and returns true if it is “empty” and false if it is “needs confirmation” or “confirmed.” NeedsConfirmation( ) This method checks to see if the state property of the Semantic Item and returns true if it is “needs confirmation” and false if it is “empty” or “confirmed.” IsConfirmed( ) This method checks to see the state property of the Semantic Item and returns true if it is “confirmed” and false if it is “needs confirmation” or “empty.” Encode( ) Object Value ReadOnly. string state Read Only. Object Attributes 14.3 Run-Time Behavior As a general rule, the order of execution for every transition Empty->NeedsConfirmation or NeedsConfirmation->Confirmed: Client-side binding (if needed) Client-side event If (Autopostback), trigger submit. On the server, the order of execution is: Server-side binding (if needed) Server-side event. If the semantic item is programmatically changed in the server, no events (server or client side) will be thrown. If (BindOnChanged=false) and (Autopostback=true) and we have both Changed and Confirmed handlers, both events will be triggered, in order. Changed events will be thrown in the server (if needed and handlers are set) even if the server-side value is the same as the previous one (didn't change apparently). If AutoPostBack is set to true, the controls will cause two postbacks, synchronized with onChanged, and onConfirmed. 15 Prompt Object The prompt object contains information on how to play prompts. All the properties defined are read/write properties. Rendered for voice-only. Not rendered for multimodal. How Prompt Object is Used Voice-Only The Prompt object is a required element of the QA control. RunSpeech uses the Prompt object to select the appropriate text for the prompt and then play the prompt on the client. After RunSpeech determines which QA to activate it either increments or initializes the count attribute of the QA. The count attribute is incremented if the QA being activated was the same QA that was active during the last loop through RunSpeech. The count attribute is initialized to count=1 if this is the first time the QA has been activated. The QA's count attribute may be used by the script specified in the PromptSelectFunction attribute of the Prompt object. RunSpeech then sets out to determine which text will be synthesized and played back to the user. The dialog author has the option of providing a script function for prompt text that is complex to build, or simply specifying the prompt text as content of the Prompt object. If RunSpeech detects the existence of an author-specified PromptSelectFunction, it passes the text returned from the PromptSelectFunction to the speech platform for synthesis and playback to the user. Otherwise RunSpeech will pass the text in the content of the Prompt object to the speech platform. If a serious or fatal error occurs during the synthesis process, the speech platform will fire the onError event. RunSpeech receives this event, sets lastCommandOrException to “PromptError” and calls the script function specified by the OnClientError attribute. The dialog author may then choose to take appropriate action based upon the type of error that occurred. After the prompt playback has finished, the speech platform fires the oncomplete event which is caught by RunSpeech. RunSpeech then looks for the Reco object associated with the current QA. If a Reco object is found (i.e., the QA is not just a prompting mechanism), RunSpeech requests the speech platform to start the recognition process. Finally, RunSpeech examines the value of the PlayOnce attribute of the QA containing the Prompt object. If PlayOnce is true, RunSpeech disables the Prompt object for subsequent activations of this same QA. If speech is detected during the playing of the prompt, the playback of the prompt will be stopped automatically by the platform. RunSpeech catches the onbargein event and halts execution. Since a prompt.OnComplete event may not follow a bargein, RunSpeech resumes when a listen event is received. If a bookmark is encountered, Runspeech activates the function specified by the OnClientBookmark property. Multimodal. The Prompt object is not used in multimodal scenarios. PromptSelectFunction The following three examples illustrate using the PromptSelectionFunction to select or modify prompt text using the parameters available to PromptSelectFunction. The first example shows how to use the count parameter to select a prompt based upon the number of times the QA has been activated. The scenario is: A user calls a menu based service, enters password. Server-side processing determines the user's first and last name and inserts the name information into hidden textboxes (txtFirstName.value and txtLastName.value) on the welcome page. The welcome page contains a QA which prompts the user to enter the desired service. The QA's Prompt object is built to handle 1) the prompt to play for a first time pass and 2) the prompt to play if the user fails to select a service at the first prompting (i.e., the same QA is activated after a timeout expires). <speech:QA id=“welcomeQA” runat=“server”> <Prompt id=“welcomePrompt” PromptSelectFunction=“SelectWelcomePrompt” /> <Reco id=“welcomeReco” mode=“automatic”> <Grammars> <speech:grammar id=“welcomeGrammar” src=“http://mysite/services.xml” runat=“server” /> </Grammars> </Reco> <Answers> <speech:answer id=“servicesAnswer” SemanticItem = “siService” runat=“server” /> </Answers> </speech:QA> <script> function SelectWelcomePrompt(lastCommandOrException, count, assocArray) { switch(count) { case 1: retrun “Welcome to Acme Services <SALT:value>textFirstName.value</SALT:value>. Please select the Email, Calendar or Stock service.”; case 2: return “Welcome Please select the Email, Calendar or Stock service.”; case 3: return “Welcom Please select the Email, Calendar or Stock service.”; default: retrun “I'm sorry <SALT: value>txtFirstName.value</SALT:value>, we're having communication problems. Good Bye.”; } } </script> The next example shows how to use the lastCommandOrException parameter to modify a prompt based upon a event previous event in the dialog. The scenario is: A user is asked to provide the name of a departing airport. The QA contains a Prompt object that is built to handle the initial prompt, a prompt if the user asks for help, and a prompt if the user fails to respond (i.e. a timeout occurs). <speech:qa id=“qa1” runat=“server”> <Prompt id=“prompt1” PromptSelectFunction=“SelectDepartingAirport” /> <Reco id=“reco1” mode=“automatic”> <Grammars> <speech:grammar id=“gram1” src=“http://mysite/NYAirport.xml” runat=“server” /> </Grammars> </Reco> <Answers> <speech:answer id=“ans1” SemanticItem=“siAns1” runat=“server” /> </Answers> </speech:qa> <speech:command id=“command1” runat=“server” XpathTrigger=“/sml/help” scope=“qa1” type=“HELP”> <Grammar src=“http://mysite/help.xml” runat=“server” /> </speech:command> <script> function SelectDepartingAirport(lastCommandOrException, count, assocArray) { if (count==1) return “From which airport would you like to depart?”; switch(lastCommandOrException) { case “SILENCE”: retrun “I'm sorry I didn't catch that. From which airport would you like to depart?”; case “HELP”: retrun “You may choose from Kennedy, LaGuardia, or that little airport on Long Island. From which airport would you like to depart?”; default retrun “What we have here is a failure to communicate. Good bye.”; } } </script> The last example shows how to use the assocArray parameter to modify a prompt during a confirmation pass. The scenario is: The user is asked to provide itinerary details: departing and arrival cities and travel date. The QA is constructed to implicitly confirm the departing and arrival city information and explicitly confirm the travel date. The Prompt object is built to provide appropriate prompting of items requiring confirmation. <speech:qa id=“qa1” runat=“server”> <Prompt id=“prompt1” InLinePrompt=“What is your desired itinerary?”></Prompt> <Reco id=“reco1” mode=“Automatic”> <Grammars> <speech:grammar id=“grm1” src=“http://mysite/city_date.xml” runat=“server” /> </Grammars> </Reco> <Answers> <speech:answer id=“A1” XpathTrigger=“/sml/departCity” SemanticItem=“siTb1” ConfirmThreshold=“0.90” runat=“server” /> <speech:answer id=“A2” XpathTrigger=“/sml/arrivalCity” SemanticItem=“siTb2” ConfirmThreshold=“0.90” runat=“server” /> <speech:answer id=“A3” XpathTrigger=“/sml/departDate” SemanticItem=“siTb3” ConfirmThreshold=“1.00” runat=“server” /> </Answers> </speech:qa> <speech:qa id=“qa2” runat=“server” XpathDenyConfirms=“/sml/deny” XpathAcceptConfirms=“/sml/accept”> <Prompt id=“prompt2” PromptSelectFunction=“myPromptFunction” /> <Reco id=“reco2” mode=“automatic”> <Grammars> <speech:grammar id=“grm2” src=“http://mysite/cityANDdateANDyes_no.xml” runat=“server” /> </Grammars> </Reco> <Confirms> <speech:answer id=“conf1” XpathTrigger=“/sml/departCity” SemanticItem=“siTb1” ConfirmThreshold=“0.90” runat=“server” /> <speech:answer id=“conf2” XpathTrigger=“/sml/arrivalCity” SemanticItem=“siTb2” ConfirmThreshold=“0.90” runat=“server” /> <speech:answer id=“conf3” XpathTrigger=“/sml/departDate” SemanticItem=“siTb2” ConfirmThreshold=“1.00” runat=“server” /> </Confirms> </speech:qa> <script> function myPromptFunction(lastCommandOrException, count, assocArray) { var promptext = ”Did you say “; if (assocArray[“siTb1”] !=null && assocArray[“siTb1”] !=””) { promptText += “from” + assocArray[“siTb1”]; return promptText; } if (assocArray[“siTb2”] !=null && assocArray[“siTb2”] !=””) { promptText += “to” + assocArray[“siTb2”]; return promptText; } if (assocArray[“siTb1”] !=null && assocArray[“siTb3”] !=””) { promptText += “on” + assocArray[“siTb3”]; return promptText; } } </script> class Prompt : Control { string id{get; set;}; string type{get; set;}; bool prefetch{get; set;}; string lang{get; set;}; bool bargein{get; set;}; string src{get; set;}; string PromptSelectFunction{get; set;}; string OnClientBookmark{get; set;}; string OnClientError{get; set;}; string InlinePrompt{get; set;}; string StyleReference{get; set;}; ParamCollection Params{get; set:}; } 15.1 Prompt Properties All properties of the Prompt object are available at design time. type Optional. Only used in voice-only mode. The mime-type corresponding to the speech output format used. No default value. The type attribute mirrors the type attribute on the SALT Prompt object. prefetch Optional. Only used in voice-only mode. Flag to indicate whether the prompt should be immediately synthesized and cached at browser when the page is loaded. Default value is false. The prefetch attribute mirrors the prefetch attribute on the SALT Prompt object. lang Optional. Only used in voice-only mode. Specifies the language of the prompt content. The value of this attribute follows the RFC xml:lang definition. Example: lang=“en-us” denotes US English. No default value. If specified, this over-rides the value set in the Web.config file. The lang attribute mirrors the lang attribute on the SALT Prompt object. bargein Optional. Used only for voice-only mode. Flag that indicates whether or not the speech platform is responsible for stopping prompt playback when speech or DTMF input is detected. If true, the platform will stop the prompt in response to input and flush the prompt queue. If false, the platform will take no default action. If unspecified, default to true. PromptSelectFunction Optional. Only used in voice-only mode. Specifies a client-side function that allows authors to select and/or modify a prompt string prior to playback. The function returns the prompt string. PromptSelectFunction is called once the QA has been activated and before the prompt playback begins. If PromptSelectFunction is specified, src and InLinePrompt are ignored. The signature for PromptSelectFunction is as follows: String PromptSelectFunction(string lastCommandOrException, int Count, object SemanticItemList) where: lastCommandOrException is a Command type (e.g., “Help”) or a Reco event (e.g., “Silence” or “NoReco”). Count is the number of times the QA has been activated consecutively. Count starts at 1 and has no limit. SemanticItemList For voice-only mode, SemanticItemList is an associative array that maps semantic item id to semantic item objects. For multimodal, SemanticItemList will be null. If the PromptSelectFunction is being called from within a Prompt object specified by a CustomValidator control, the SemanticItemList will contain the SemanticItem being validated. If the PromptSelectFunction is being called from within a Prompt object specified by a CompareValidator control, the SemanticItemList will contain the SemanticItem being validated and (if specified) the SemanticItem to which it is being compared. OnClientBookmark Optional. Only used in voice-only mode. Specifies a client side function which is called when a Bookmark is reached in the prompt text during playback. The function does not return a value. The signature for OnClientBookmark is as follows: function OnClientBookmark( ) OnClientError Optional. Only used in voice-only mode. Specifies a client side function which is called in response to an error event in the client. Error events are generated from the event object. The function returns a Boolean value. The RunSpeech algorithm will continue executing if an OnClientError script returns true. The RunSpeech algorithm will navigate to the default error page specified in the Web.config file if an OnClientError script returns false or if an error occurs and the OnClientError function is not specified. When navigating to the error page, both status and description will be passed in the query string. For example, if the error page is http://myErrorPage, we will navigate to http://myErrorPage?status=X&description=Y (where X is the status code associated with the error and Y is the description of that error given in the Speech Tags Specification. The signature for OnClientError is as follows: bool OnClientError(int status) where status is the code returned in the event object. Note: For the SDK Beta release, it is advisable to specify a default error page using the syntax described in Section 5 Global Application Settings. InlinePrompt Optional. Only used in voice-only mode. The text of th prompt to be played. It may contain further markup, as in TTS rendering information, or <value> elements. If a PromptSelectFunction function is specified, the InlinePrompt is ignored. StyleReference Optional. Used in both multimodal and voice-only modes. Specifies the name of a Style object. At render time, the Prompt object will search for the named Style control and will use any property values specified on the Style as default values for its own properties. Explicitly set property values by the Prompt object will override those set on the referenced Style. Params Optional. An collection of param objects that specify additional, non-standard configuration parameter values to the speech platform. The exact nature of the configurative parameters will differ according to the proprietary platform used. Values of parameters may be specified in an XML namespace, in order to allow complex or structured values. An exception will be thrown if the Params collection contains a non-param object. For example, the following syntax could be used to specify the location of a remote prompt engine for distributed architectures: <Params> <speech:param name=“promptServer” runat=”server”>//myplatform/promptServer</speech:param> </Params> 16 Reco Object Reco is rendered for both multimodal and voice-only modes. The Reco object is used to specify speech input resources and features as well as provide for the management of cases when vaild recognition results are not returned. How Reco object is used. Voice-Only During the processing of the Prompt object, RunSpeech determines whether or not the currently active QA contains a Reco object. If it does, RunSpeech asks the speech platform to start the recognition process using the grammar specified by the Reco's Grammar object. RunSpeech calls the function specified by OnClientListening immediately after activating the Reco's underlying <listen> tag. The recognition process is stopped depending on the value of the mode attribute. RunSpeech processes successful recognition results using information specified in the Answer object. RunSpeech uses the Reco object to handle the situations when the speech platform is not able to return valid recognition results, i.e., speech platform errors, timeouts, silence, or inability of the speech platform to recognize an utterance. In each of these cases, RunSpeech calls the appropriate handler (if specified) after setting the value of the lastCommandOrException attribute. Multimodal The Reco object is used by the Multimodal.js client-side script just as it is used by the RunSpeech voice-only client-side script (as described above) with one exception, starting/stopping the recognition process. Multimodal scenarios do not require speech output as a mechanism to prompt the user for input. In fact, prompting in speech controls is not available in multimodal scenarios as the Prompt object is not rendered to the client. Therefore, an alternate mechanism is required to start the recognition process. Multimodal.js uses the event specified in the StartElement/StartEvent attributes to start the recognition process. The function specified by the OnClientListening attribute is called after the recognition process has started. Multimodal.js uses the combination of the StopEvent and mode attributes to stop the recognition process. class Reco : Control { string id{get; set;}; string StartElement{get; set;}; string StartEvent{get; set;}; string StopElement{get; set;}; string StopEvent{get; set;}; int initialTimeout{get; set;}; int babbleTimeout{get; set;}; int maxTimeout{get; set;}; int endSilence{get; set;}; float reject{get; set;}; string mode{get; set;}; string lang{get; set;}; string GrammarSelectFunction{get; set;}; string OnClientSpeechDetected{get; set;}; string OnClientSilence{get; set;}; string OnClientNoReco{get; set;}; string OnClientError{get; set;}; string StyleReference{get; set;}; GrammarCollection Grammars{get; set;}; ParamCollection Params{get;set;}; Control record{get; set;}; } 16.1 Reco Properties All properties are available at design time. Start Element Optional, but must be present if StartElement is specified. Used only in multimodal mode. Specifies the name of the GUI element with which the start of the Reco is associated. See StartEvent. No default value. StartEvent Optional, but must be present if StartElement is specified. Only used in multimodal mode. Specifies the name of the event that will activate (start) the underlying client-side Reco object. See start Element No default value. Start Element Optional, but must be present if StopElement is specified. Used only in multimodal mode. Specifies the name of the GUI element with which the stop of the Reco is associated. See StopEvent. No default Value. StopEvent Optional, but must be present if StartElement is specified. Only used in multimodal mode. Specifies the name of the event that will stop the underlying client-side Reco object. See stop Element. No default value. StartEvent and StopEvent will be used in multi-modal applications, typically for tap-and-talk interactions. E.g. StartEvent=Button1.onmousedown, StopEvent=Button1.onmouseup. StartEvent and StopEvent are allowed to be the same (click to start, click to stop). However, it is the author's responsibility to de-activate Recos before starting new ones in the case when the end user fires two StartEvents in succession (e.g., click on one control to start a reco then click on a different control to start another reco before stopping first reco). Note: IE requires exact cases when running Jscript. Therefore, the the case for event values specified in the StartEvent and StopEvent attributes must be exactly as those events are defined. For example, the onmouseup and onmousedown events are specified in all lower case letters. Note: StartEvent and StopEvent are not rendered for voice-only mode. initialTimeout Optional. Used in both multimodal and voice-only modes. The max time in milliseconds between start of recognition and the detection of speech. This value is passed to the recognition platform, and if exceeded, an onSilence event will be thrown from the recognition platform. If not specified, the speech platform will use a default value. No default value. An exception will be thrown for non-integer or negative integer value. Note: The sum of the initialTimeout and babbleTimeout values should be smaller or equal to the global maxTimeout attribute or the Reco attribute maxTimeout (see below) if it is set. Note: The initialTimeout attribute mirrors the initialTimeout attribute on the SALT Reco object. babbleTimeout Optional. Used in both multimodal and voice-only modes. Optional. The maximum period of time in milliseconds for an utterance. For recos in automatic and single mode, this applies to the period between speech detection and the speech endpoint or stop call. For recos in ‘multiple’ mode, this timeout applies to the period between speech detection and each phrase recognition—i.e. the period is restarted after each return of results or other event. If exceeded, the onnoreco event is thrown with status code −15. This can be used to control when the recognizer should stop processing excessive audio. For automatic mode listens, this will happen for exceptionally long utterances, for example, or when background noise is mistakenly interpreted as continuous speech. For single mode listens, this may happen if the user keeps the audio stream open for an excessive amount of time (eg by holding down the stylus in tap-and-talk). If the attribute is not specified, the speech platform will use a default value. No default value. An exception will be thrown for non-integer or negative integer values. Note: The sum of the initialTimeout and babbleTimeout values should be smaller or equal to the global maxTimeout attribute or the Reco attribute maxTimeout (see below) if it is set. Note: The babbleTimeout attribute mirrors the babbleTimeout attribute on the SALT Reco object. maxTimeout Optional. Used in both multimodal and voice-only modes. The period of time in milliseconds between recognition start and results returned to the browser. If exceeded, an OnError event is thrown by the browser—this provides for network or recognizer failure in distributed environments. For Recos in “multiple” mode, as with babbleTimeout, the period is restarted after the return of each recognition or other event. No default value. An exception will be thrown for non-integer or negative integer values. Note: maxTimeout should be greater than or equal to the sum of initialTimeout and babbleTimeout. If specified, the value of this attribute over-rides the value of maxTimeout set in the Web.config file. No default value. Note: The maxTimeout attribute mirrors the maxTimeout attribute on the SALT Reco object. endSilence Optional. Used in both multimodal and voice-only modes. For Reco objects in “automatic” mode, the period of silence in milliseconds after the end of an utterance which must be free of speech after which the recognition results are returned. Ignored for Recos of modes other than “automatic”. If not specified, defaults to platform internal value. An exception will be thrown for non-integer or negative integer values. Reject Optional. Used in both multimodal and voice-only modes. Specifies the rejection threshold, below which the platform will throw the noReco event. If not specified, the speech platform will use an internal default value. Legal values are 0-1 and are platform specific. An exception will be thrown for out of range reject values. Default is 0. Lang Optional. Used in both multimodal and voice-only modes. Specifies the language of the speech recognition engine. The value of this attribute follows the RFC xml:lang definition. Example: lang=“en-us” denotes US English. No default value. This over-rides the global setting in the Web.config file. The lang attribute mirrors the lang attribute on the SALT Reco object. Mode Optional. Used in both multimodal and voice-only modes. Specifies the recognition mode to be followed. Default is “automatic”. Legal values are “automatic”, “single”, and “multiple”. Mode=“Automatic” Used for recognitions in telephony scenarios. The speech platform itself (not the application) is in control of when to stop the recognition process. Mode=“automatic” is the only mode setting that works in voice-only, other modes will be ignored and “automatic” will be used. Mode=“Single” Used for multimodal (tap-to-talk) scenarios. The return of a recognition result is under the control of an explicit call to stop the recognition process by the application. However, exceeding babbleTimeout or maxTimeout will stop recognition. Mode=“single” is ignored for voice-only. Mode=“Multiple” Used for “open-microphone” or dictation scenarios. Recognition results are returned at intervals until the application makes an explicit call to stop the recognition process (or babbleTimeout or maxTimeout periods are exceeded). Multiple mode recos are not supported in voice-only mode dialogs. If the browser is a voice-only browser and reco mode is set to “multiple”, an exception will be thrown at render time. Mode=“multiple” is ignored for voice-only. GrammarSelectFunction Optional. Used in both multimodal and voice-only modes. Specifies a client-side script that will be called prior to starting the recognition process. The script is written by the dialog author and may be used to select or modify the Grammar objects associated with the Reco object. The script may also be used to adjust speech recognition features or confidence/rejection thresholds. The GrammarSelectFunction function does not return values. The signature for GrammarSelectFunction is as follows: function GrammarSelectFunction(object recoObj, string lastCommandOrException, int Count, object SemanticItemList) where: recoObj is the Reco object about to start. lastCommandOrException is a Command type (e.g., “Help”) or a Reco event (e.g., “Silence” or “NoReco”). For multimodal dialogs, lastCommandOrException will be an empty string Count is the number of times the QA containing the Reco object has been activated consecutively. Count starts at 1 and has no limit. For multimodal dialogs, count will be zero. SemanticItemList For voice-only mode, SemanticItemList is an associative array that maps semantic item id to semantic item objects. For multimodal dialogs, SemanticItemList will be null. OnClientSpeechDetected Optional. Used in both multimodal and voice-only modes. Specifies a client-side script function that will be called when the onspeechdetected event is fired by the speech recognition platform on the detection of speech. Determining the actual time of firing is left to the platform (which may be configured on certain platforms using the <param> element. This may be anywhere between simple energy detection (early) or complete phrase or semantic value recognition (late). This event also triggers onbargein on a prompt which is in play and may disable the initial timeout of a started dtmf object. This function can be used in multimodal scenarios, for example, to generate a graphical indication that recognition is occurring, or in voice-only scenarios to enable fine control over other processes underway during recognition. The function does not return any values. The signature for OnClientSpeechDetected is as follows: function OnClientSpeechDetected( ) If a Dtmf object is active when the OnClientSpeechDetected function is called, the timeouts of the Dtmf object will be disabled. OnClientSilence Optional. Used in both multimodal and voice-only modes. Specifies a client-side script that will be called after detecting silence (in response to SALT reco onSilence event). The function does not return any values. The signature for OnClientSilence is as follows: function OnClientSilence(int status) where status is the code returned in the event object. If a Dtmf object is active when the OnClientSilence function is called, the Dtmf object will be stopped. OnClientNoReco Optional. Used in both multimodal and voice-only modes. Specifies a client-side script that will be called after detecting no recognition (in response to SALT reco onNoReco event). The function does not return any values. The signature for OnClientNoReco is as follows: function OnClientNoReco(int status) where status is the code returned in the event object. If a Dtmf object is active when the OnClientNoReco function is called, the Dtmf object will be stopped. OnClientError Optional. Used in both multimodal and voice-only modes. Specifies a client side function which is called in response to an error event in the client. Error events are generated from the event object. The function returns a boolean value. The RunSpeech algorithm will continue executing if an OnClientError script returns true. The RunSpeech algorithm will navigate to the default error page specified in the Web.config file if an OnClientError script returns false or if an error occurs and the OnClientError function is not specified. When navigating to the error page, both status and description will be passed in the query string. For example, if the error page is http://myErrorPage, we will navigate to http://myErrorPage?status=X&description=Y (where X is the status code associated with the error and Y is the description of that error given in the Speech Tags Specification. The signature for OnClientError is as follows: bool OnClientError(int status) where status is the code returned in the event object. Note: the return value of OnClientError is ignored in multimodal mode. If a Dtmf object is active when the OnClientError function is called, the Dtmf object will be stopped. StyleReference Optional. Used in both multimodal and voice-only modes. Specifies the name of a Style object. At render time, the Reco object will search for the named Style control and will use any property values specified on the Style as default values for its own properties. Explicitly set property values by the Reco object will override those set on the referenced Style. Grammars Optional. An array of grammar objects as specified below. An exception will be thrown if a Grammars collection contains a non-grammar object. Params Optional. Used in both multimodal and voice-only modes. An collection of param objects that specify additional, non-standard configuration parameter values to the speech platform. The exact nature of the configurative parameters will differ according to the proprietary platform used. Values of parameters may be specified in an XML namespace, in order to allow complex or structured values. An exception will be thrown if the Params collection contains a non-param object. For example, the following syntax could be used to specify the location of a remote speech recognition server for distributed architectures: <Params> <speech:param name=“recoServer” runat=”server”>//myplatform/recoServer</speech:param> </Params> Record Optional. Used in both multimodal and voice-only modes. The record object is used for recording audio input from the user. Recording may be used in addition to recognition or in place of it, according to the abilities of the platform and its profile. Only one record object is permitted in a single <reco>. 17 Grammar Object The grammar object contains information on the selection and content of grammars, and the means for processing recognition results. All the properties defined are read/write properties. class Grammar : Control { string id{get; set;}; string type{get; set;}; string lang{get; set;}; string src{get; set;}; string InLineGrammar{get; set;}; string StyleReference{get; set;}; } 17.1 Grammar Properties Grammar is rendered for both multimodal and voice-only modes. All properties are available at design time and run time. Type Optional. Used in both multimodal and voice-only modes. The mime-type corresponding to the grammar format used. No default value. The type attribute mirrors the type attribute on the SALT Grammar object. Lang Optional. Used in both multimodal and voice-only modes. String indicating which language the grammar refers to. The value of this attribute follows the RFC xml:lang definition. Example: lang=“en-us” denotes US English. No default value. Over-rides the global value set in the Web.config file. The lang attribute mirrors the lang attribute on the SALT Grammar object. Src Optional. Used in both multimodal and voice-only modes. Specifies the URI of the grammar to load. If an inline grammar and src are both specified the inline grammar takes precendence and src is ignored. The src attribute mirrors the src attribute on the SALT Grammar object. An exception will be thrown if one of src or InlineGrammar is not specified. InlineGrammar Optional. Used in both multimodal and voice-only modes InlineGrammar accesses the text of the grammar specified inline. If InlineGrammar and src are both specified, InlineGrammar takes precendence and src is ignored. An exception will be thrown if one of src or InlineGrammar is not specified. Inline grammars must be HTML Encoded, they are HTML encoded when sent down to the server. Authors must use > for > and < for < and adhere to all other HTML Encoding standards. It is recommended that authors use the property builder in DET, which will handle the HTML encoding automatically. StyleReference Optional. Used in both multimodal and voice-only modes. Specifies the name of a Style object. At render time, the Grammar object will search for the named Style control and will use any property values specified on the Style as default values for its own properties. Explicitly set property values by the Grammar object will override those set on the referenced Style. 18 Dtmf Object Dtmf may be used by QA controls in telephony applications. The Dtmf object essentially applies a different modality of grammar (a keypad input grammar rather than a speech input grammar) to the same question. class Dtmf : Control { string id{get; set;}; bool preflush{get; set;}; int initialTimeOut{get; set;}; int interDigitTimeOut{get; set;}; int endSilence{get; set;}; string OnClientSilence{get; set;}; string OnClientKeyPress{get; set;}; string OnClientError{get; set;}; string StyleReference{get; set;}; ParamCollection Params{get; set;}; GrammarCollection Grammars{get;set;}; } 18.1 Dtmf Properties All properties are available at design time. Preflush Optional. Flag to indicate whether to automatically flush the DTMF buffer on the underlying telephony interface card before activation. Default is “false” (to enable type-ahead functionality). The preflush attribute mirrors the preflush attribute on the SALT DTMF object. InitialTimeOut Optional. The number of milliseconds to wait for receiving the first key press before raising a timeout event. If this timeout occurs the DTMF collection end automatically. If unspecified, initialTimeout defaults to a telephony platform internal setting. An exception is thrown if initialTimeout is a negative value. The initialTimeout attribute mirrors the initialTimeout attribute on the SALT DTMF object. InterdigitTimeOut Optional. The timeout period in milliseconds for adjacent DTMF presses before raising a timeout event. If this timeout occurs the DTMF collection ends automatically. If unspecified, interdigitTimeout defaults to a telephony platform internal setting. An exception is thrown if initialTimeout is a negative value. The interdigitTimeout attribute mirrors the interdigitTimeout attribute on the SALT DTMF object. EndSilence Optional. The timeout period in milliseconds when input matches a complete path through the grammar but further input is still possible. This timeout specifies the period of time in which further input is permitted after the complete match. Once exceeded, onreco is thrown. (For a complete grammar match where further input is not possible, the endsilence period is not required, and onreco is thrown immediately.) If this attribute is not supported directly by a platform, or unspecified in the application, the value of endsilence defaults to that used for interdigittimeout. An exception is thrown if endSilence is a negative value. OnClientSilence Optional. Specifies a client-side script function to be called if there is no DTMF key press before initialTimeout expires. The platform halts DTMF collection automatically. The QA treats this as a silence. The function returns no values. The signature for OnClientSilence is as follows: function OnClientSilence( ) If a Reco object is active when the OnClientSilence function is called, the Reco object will be stopped. OnClientKeyPress Optional. Specifies a client-side script function that is called on every pressing of a DTMF key which is legal according to the input grammar. If a prompt is in playback, the onkeypress event will trigger the onbargein event on the prompt (and cease its playback if the prompt's bargein attribute is set to true). If a Reco object is active, the first onkeypress event will disable the timeouts of the Reco object. OnClientError Optional. Specifies a client-side function which is called in response to a serious or fatal error with the DTMF collection/recognition process. Error events are generated from the event object. The function returns a boolean value. The RunSpeech algorithm will continue executing if an OnClientError script returns true. The RunSpeech algorithm will navigate to the default error page specified in the Web.config file if an OnClientError script returns false or if an error occurs and the OnClientError function is not specified. When navigating to the error page, both status and description will be passed in the query string. For example, if the error page is http://myErrorPage, we will navigate to http://myErrorPage?status=X&description=Y (where X is the status code associated with the error and Y is the description of that error given in the Speech Tags Specification. The signature for OnClientError is as follows: bool OnClientError(int status) where status is the code returned in the event object. If a Reco object is active when the OnClientError function is called, the Reco object will be stopped. OnClientNoReco Optional. Specifies a client side function which is called in response to a failure to recognize by the DTMF collection/recognition process. This is most lokely to occur when the input detected does not match an path through the active grammars. The function does not need to return a value. The prototype for the function is: OnClientNoReco(int status) Where status is the code returned the in the event object. StyleReference Optional. Used in both multimodal and voice-only modes. Specifies the name of a Style object. At render time, the Dtmf object will search for the named Style control and will use any property values specified on the Style as default values for its own properties. Explicitly set property values by the Dtmf object will override those set on the referenced Style. Grammars Optional. An array of grammar objects. Params An collection of param objects that specify additional, non-standard configuration parameter values to the speech platform. The exact nature of the configurative parameters will differ according to the proprietary platform used. Values of parameters may be specified in an XML namespace, in order to allow complex or structured values. An exception will be thrown if the Params collection contains a non-param object. For example, the following syntax shows how to specify a parameter on particular DTMF platform. <Params> <speech:param name=“myDTMFParam” runat=”server”> myDTMFValue </speech:param> </Params> 19 Param Object The param object allows authors to specify the names and values of additional, non-standard configuration parameters to the speech platform. The exact nature of the configurative parameters will differ according to the proprietary platform used. Values of parameters may be specified in an XML namespace, in order to allow complex or structured values. class param : Control { string name{get; set;}; string Value{get; set;}; } Note that the value of a param object is specified between the param tags. 19.1 Param Properties Name Required. The name of the parameter to be configured. An exception will be thrown for <param> elements that do not contain the name attribute. Value Optional. The value which will be assigned to the named parameter. 20 Record Object The record object is used to record audio input from the user. Recording may be used in addition to recognition or in place of it, according to the abilities of the platform and its profile. class record : Control { bool enabled{get; set;}; string type{get; set;}; bool beep{get; set;}; } 20.1 Record Properties Enabled Optional. Flag to indicate whether or not to record the user input. Defaults to “false”. Type Optional. MIME type of the recording. MIME types can be specified such as “audio/wav” for WAV (RIFF header) 8 kHz 8-bit mono mu-law [PCM] single channel or “audio/basic” for Raw (headerless) 8 kHz 8-bit mono mu-law [PCM] single channel. If unspecified, defaults to G.711 wave file. Beep Optional. Boolean value, if true, the platform will play a beep before recording begins. Defaults to false. 21 Call Control All call-related server-side controls deal with a single device and a single active call at any given time. If the dialog author needs to monitor more than one device or handle more than one active call, the custom SmexMessage can be used and the author will have to handle CSTA messages. All call control controls are only used in voice-only mode. The SpeechControls.dll will implement a support class (CallInfo), a base class (SmexMessageBase), and the following WebControls: SmexMessage for custom/advanced CSTA messages, and messages to any non-CSTA <smex> elements by specifying a client side <smex> element TransferCall for CSTA SingleStepTransfer service MakeCall for CSTA MakeCall service DisconnectCall for CSTA ClearConnection service AnswerCall for CSTA AnswerCall service 21.1 Common Classes 21.1.1 CallInfo class CallInfo { string MonitorCrossRefId {get;}; string DeviceId {get;}; string CallId {get;}; string CallingDevice {get;}; string CalledDevice {get;}; } 21.1.1.1 CallInfo Properties MonitorCrossRefId: The id returned by the start page's MonitorStart. DeviceId: The device id for the current active call. CallId: The call id for the current active call. These properties can be used in the custom SmexMessage object to form the correct CSTA xml message on the web server side. CallingDevice: This represents the calling device information provided by the network (ANI, for example). This information will always remain with the call and will never change (unlike the callingDevice). CalledDevice: This represents the called device information provided by the network (DNIS, for example). This information will always remain with the call and will never change (unlike the calledDevice). 21.1.2 SmexMessageBase This is an internal class. Authors that need to create new call-control controls should derive from SmexMessage. internal class abstract SmexMessageBase { string ID {get; set }; int Timer (get; set}; bool AutoPostback {get; set}; string ClientActivationFunction {get; set}); string OnClientError {get, set}; string OnClientTimeout {get; set}; CallInfo CurrentCall {get; } } 21.1.2.1 SmexMessageBase Properties ID: ASP.NET control ids. SpeechIndex: Same as for other speech controls controls. This index controls the order of the object within RunSpeech. Default 0, meaning source order after all non-zero indexed speech objects. Timer: Number in milliseconds indicating the time span before a timeout event will be triggered. This set on the client side <smex> object before the CSTA message is sent. The default is 0, meaning no timeout. An exception will be thrown for neagtive values of Timer. AutoPostback: Whether to cause a postback when the object's event is fired. Default is false. ClientActivationFunction: The client side function called by RunSpeech to determine whether an object is active. When not specified, the object is considered active only once (the PlayOnce behavior). ClientActivationFunction returns a bool to indicate whether the associated object should be active (true) or not (false). The signature for ClientActivationFunction is: function ClientActivationFunction(object sender) where sender is the current object. OnClientError: Optional. Default is false when not specified. The client side function called when <smex> fires the onerror event. OnClientError returns a bool—true to continue RunSpeech and false to go to the error page. The signature for OnClientError is: function OnClientError(object sender, int status) where sender is the current object, and status is the value of the object's status property. OnClientTimeout: Optional. Default is true when not specified. The client side function called when <smex> fires the ontimeout event. OnClientTimeout returns a bool—true to continue RunSpeech and false to go to the error page. The signature for OnClientTimeout is: function OnClientTimeout(object sender) where sender is the current object. CurrentCall: Returns the current active call object. 21.2 Server-Side Classes 21.2.1 SmexMessage This is a generic class for sending raw CSTA messages and receiving CSTA events. Since the number and types of events generated by this message is unknown, the author needs to be careful about when RunSpeech can continue. RunSpeech will be paused just before calling author's OnClientBeforeSend function when the message is about to be sent. If OnClientReceive is not specified, RunSpeech will resume when any smex event is received after message is sent. If OnClientReceive is specified, the author returns true to indicate RunSpeech can resume after receiving the expected event. RunSpeech will resume after Error or Timeout happens. The Smex Timer will be set to the given value before the message is sent and back to zero right before RunSpeech resumes. When an unexpected smex event arrives, i.e. when the current active object in RunSpeech is not a call related object, the smex event is ignored. When AutoPostback is set to true, all events will execute the client handler, then cause a post-back to the web server where the corresponding server event will be fired. class SmexMessage : SmexMessageBase { string Message {get; set}; string ClientSmexId {get; set}; string OnClientBeforeSend {get; set}; string OnClientReceive {get; set}; event Receive; } 21.2.1.1 SmexMessage Properties Message: Required. The CSTA XML message to be sent. An exception will be thrown if Message is not specified. OnClientBeforeSend: Optional. Client side function called just before the message is sent. This is to give the author a last chance to modify the message. OnClientBeforeSend returns a string containing the new message. If null is returned, original message will be sent. The signature for OnClientBeforeSend is: function OnClientBeforeSend(object sender, string Message ) where: sender is the client-side SmexMessage object, and Message is the original message. Receive: Optional. Server side event when client side <smex> object receives smex events. The signature of a ReceiveEventHandler is: void ReceiveEventHandler(object sender, ReceiveEventArgs e) where sender will be the server side SmexMessage object. The second argument e is of following type: class ReceiveEventArgs : EventArgs { string Received {get}; } where Received contains the event message received from <smex>. OnClientReceive: Optional. Client-side function called when client side <smex> object receives smex events. OnClientReceive returns a bool—true means that this object has got all the events and RunSpeech can continue, false means that this object expects more events before RunSpeech can continue. The signature for OnClientReceive is: function OnClientReceive(object sender, string Message) where sender is the client-side SmexMessage object, and Message is the received message. ClientSmexId: Optional. This is the client side <smex> element id. If not set, messages will be sent through the default Call Manager <smex> element. If set to non-empty string, it has be to be id of an existing SALT <smex> element, which the author has to add to the page. 21.2.2 TransferCall The TransferCall control transfers the current call using CSTA SingleStepTransfer service. When RunSpeech runs this object, it blocks any further speech dialog until transfer succeeds or fails. class TransferCall : SmexMessageBase { string TransferredTo {get; set}; string OnClientFailed {get; set}; string OnClientTransferred {get; set}; event Transferred; } 21.2.2.1 TransferCall Properties TransferredTo: Required. The device identifier associated with the transferred to endpoint. Transferred: Optional. Server side event fired when the call is transferred. The signature of an EventHandler is: void EventHandler(object sender, EventArgs e); where sender is the server side TransferCall object, and e is of the standard EventArgs type. OnClientTransferred: Optional. Client side function called when the call is transferred. OnClientTransferred returns nothing. The signature of OnClientTransferred is function OnClientTransferred(object sender) where: sender is the client-side TransferCall object. OnClientFailed: Client-side function called when CSTA returns FAILED event. OnClientFailed returns a bool—true to continue RunSpeech and false to go to error page. The signature for OnClientFailed is: function OnClientFailed(object sender, string cause) where sender is the client-side TransferCall object, and cause is the reason for failure returned from <smex>. 21.2.3 MakeCall The MakeCall control makes an outbound call to the given number on the given device when RunSpeech runs this object. Further speech dialog is blocked until the call is connected or fails to connect. class MakeCall : SmexMessageBase { string CallingDevice {get; set} string CalledDirectoryNumber {get; set}; string OnClientFailed {get; set}; string OnClientConnected {get; set}; event Connected; } 21.2.3.1 MakeCall Properties CallingDevice: Required. Default is the internal CallInfor DeviceId. The control will use this device to place the outbound call. CalledDirectoryNumber: Required. Phone number to dial. An exception will be thrown if CalledDirectoryNumber is not specified. Connected: Server side event when the call is connected. The signature of an EventHandler is: void EventHandler(object sender, EventArgs e) where sender is the server side MakeCall object, and e is of the standard EventArgs type. At this point, the CurrentCall property should contain the information about the call in progress. OnClientConnected: Client side function called when the call is connected. OnClientConnected returns nothing. The signature for OnClientConnected is: function OnClientConnected(object sender, string CalledDirectoryNumber) where: sender is the client-side MakeCall object, and CalledDirectoryNumber is the property of the MakeCall object. OnClientFailed: Client side function called when CSTA returns FAILED event. OnClientFailed returns a bool—true to continue RunSpeech and false to goto error page. The signature for OnClientfailed is: function OnClientFailed(object sender, string cause) where sender is the client-side MakeCall object, and cause is the reason for failure returned from <smex>. 21.2.4 DisconnectCall class DisconnectCall : SmexMessageBase { string OnClientFailed {get; set}; string OnClientDisconnected {get; set}; event Disconnected; } 21.2.4.1 DisconnectCall Properties Disconnected: Optional. Server side event when the call is disconnected. The signature of an EventHandler is: void EventHander(object sender, EventArgs e) where: sender is the server side DisconnectCall object and, e is of the standard EventArgs type. OnClientDisconnected: Optional. Client side function called when the call is disconnected. OnClientDisconnected returns nothing. The signature for OnClientDisconnected is: function OnClientDisconnected(object sender) where sender is the client-side Disconnect Call object. OnClientFailed: Optional. Client side function called when CSTA returns FAILED event. OnClientFailed returns a bool—true to continue RunSpeech and false to goto error page. The signature for OnClientFailed is: function OnClientFailed(object sender, string cause) where sender is the client-side Disconnect Call object, and cause is the reason for failure returned from <smex>. 21.2.5 AnswerCall The AnswerCall control answers incoming calls on the given device. When activated, this object will block RunSpeech until an incoming call is answered. Server-Side Class: class AnswerCall : SmexMessageBase { string OnClientConnected {get; set}; string OnClientFailed {get; set}; event Connected; } 21.2.5.1 AnswerCall Properties Connected: Optional. Server side event when the call is connected. The signature of a ConnectedEventHandler is: void EventHandler(object sender, EventArgs e) where: sender is the server side AnswerCall object and e is of the standard EventArgs type. At this point, the CurrentCall property should contain information of the call in progress. OnClientConnected: Optional. Client side function called when the call is connected. OnClientConnected returns nothing. The signature for OnClientConected is: function OnClientConnected(object sender, string callid, string CallingDevice, string CalledDevice) where: sender is the client side AnswerCall object callid is the id of the current call CallingDevice is the caller's network device id CalledDevice is the recipient's network device id. OnClientFailed: Optional. Client side function called when CSTA returns FAILED event. OnClientFailed returns a bool—true to continue RunSpeech and false to go to error page. The signature of OnClientFailed is: function OnClientFailed(object sender, string cause) where sender is the client-side AnswerCall object. cause is the reason for failure returned from <smex>. 22 RunSpeech 22.1 Dialog Processing Algorithm The RunSpeech algorithm is used to drive dialog flow on a voice-only client. This involves system prompting and dialog management and processing of speech input. It is specified as a script file referenced by URI from every relevant speech-enabled page (equivalent to inline embedded script). Important: the RunSpeech script will be completely exposed to the public. Since it will be hosted on the application web site, authors of dialogs will be at liberty to examine, edit, replace or ignore the RunSpeech script code. Rendering of the page for voice only browsers is done in the following manner: The RunSpeech function works as follows (RunSpeech is called in response to document.onreadystate becoming “complete”): Controls considered for activation are the QA, CompareValidator and CustomValidator controls. 1. Find the first active QA or Validator control in speech index order (determining whether a QA/Validator is active is explained below). 2. If there is no active control, submit the page. 3. Otherwise, run the control. A QA is considered active if and only if: 1. The QA's clientActivationFunction either is not present or returns true, AND 2. If the Answers collection is non empty, the State of at least one of the SemanticItems pointed to by the set of Answers is Empty OR 3. If the Answers collection is empty, the State at least one SemanticItem in the Confirm array is NeedsConfirmation. However, if the QA has PlayOnce true and its Prompt has been run successfully (reached OnComplete) the QA will not be a candidate for activation. A QA is run as follows: 1. If this is a different control than the previous active control, reset the prompt Count value. 2. Increment the Prompt count value 3. If PromptSelectFunction is specified, call the function and set the Prompt's inlinePrompt to the returned string. 4. If a Reco object is present, start it. This Reco should already include any active command grammar. 5. Start the DMTF object if present. (Same concerns apply with regard to command Dtmf grammars). A Validator (either a CompareValidator or a CustomValidator) is active if: 1. The SemanticItemToValidate has not been validated by this validator. A CompareValidator is run as follows: 1. Compare the values of the ElementToCompare or ValueToCompare and SemanticItemToValidate Tovalidate according to the validator's Operator. 2. If the test returns false, empty the text field of the SemanticItemToValidate (or both if the InvalidateBoth flag is set) and play the prompt. 3. If the test returns true, mark the SemanticItemToValidate as validated by this validator. A CustomValidator is run as follows: 1. The ClientValidationFunction is called with the value of the SemanticItemToValidate. 2. If the function returns false, the semanticItem cleared and the prompt is played, otherwise as validated by this validator. A Command is considered active if and only if: 1. It is in Scope, AND 2. There is not another Command of the same Type lower in the scope tree. 22.2 LastCommandOrException LastCommandOrException is a global variable and its value is passed to several author-defined functions as a parameter. LastCommandOrException is a global variable maintained by RunSpeech. The value is set to the last Command.Type or recognition exception that occurred. The value will be reset to “ ” when there is a QA transition (the current active QA is different than the previously active QA, or is the first active QA). There is one exception to this rule: If the QA is in a Short time-out confirmation state, and the current recognition result is “Silence”, the LastCommandOrException will be set to “ ” (silence in Short time-out confirmation is not an exception, but a valid input.) In this fashion, ClientActivationFunction will always get the LastCommandOrException that occurred anywhere in the page, but the rest of the functions of the active QA will only get a non-empty LastCommandOrException if they have been activated more than once in a row. If, after processing all the Answers, ExtraAnswers and Confirms in a QA, nothing is matched (either due to a mismatch in the sml returned or to a high reject threshold), the LastCommandOrException will be set to “NoReco”. Active Validators will also reset the global LastCommandOrException. Possible values of LastCommandOrException are: platform event LastCommandOrException Prompt fires an onerror event “PromptError”. Reco fires an onerror event “RecoError”. Dtmf fires an onerror event “DtmfError”. Reco fires an onnoreco event “NoReco”. Reco fires a silence event “Silence”. Command is Activated Command.type Transition to new QA “” Also, a PromptSelectFunction's LastCommandOrException will have the value “ShortTimeoutConfirmation” when its QA is in Short Time-out Confirmation mode (i.e., when count==1, firstInitialTimeout is non-zero, etc.) 22.3 Count Count is exclusively local—both in ClientActivationFunction and the rest of the functions which are passed count. That is, these functions are always passed the count of their own QA. To avoid confusion, the function ClientActivationFunction will receive the value that the PromptSelectFunction would receive if this QA was active. 22.4 Postback Support In their simplest form, ASP.NET pages are stateless. They are instantiated, executed, rendered, and disposed of on every round trip to the server. In the visual world, ASP.NET provides the ViewState mechanism to keep track of server control state values that don't otherwise postback as part of an HTTP form. The ASP.NET framework uses ViewState to manage and restore page properties prior to and after postback. For voice-only pages, the ASP.NET ViewState mechanism is not available to the web developer. However, a similar mechism is provided by RunSpeech. RunSpeech maintains an object that can be used to store values which authors wish to be persisted across postbacks. The syntax is: RunSpeech.ClientViewState[“MyVariableName”]=myVariableValue; Any JScript built-in type can be persisted—string, number, boolean, array, object, Date, RegExp, or function. The main difference between the ASP.NET ViewState (for visual pages) and the voice-only ClientViewState mechanism is that authors of voice-only pages must manually declare and set values they wish to maintain across postbacks. If AutoPostBack is set to true in any speech control, the matching client-side function will always be executed before posting back to the server. If the author wishes to persist any page state across postback, these client-side functions are a good place to invoke the ClientViewState object of RunSpeech. 23 Confirmation Algorithm Semantic Processing Algorithm: There are three stages for semantic processing: 1) Preprocessing, Carried Out when a QA is Active: This stage is responsible for creating the array of answers to be considered in this iteration. This includes all the Answers and the Confirms that need confirmation. Internally, it creates a structure as follows. Answer ID CurrentValue Answer ID CurrentValue This information that is also passed to the PromptSelectFunction, GrammarSelectFunction, etc. 2) Answer Processing In this stage, we process the Answer objects in the Answers and ExtraAnswers collections. If any item from the Answers collection is matched, a flag indicating this fact is set. Answer processing sets the confirmation status of the associated semantic item—this status can be either NEEDS_CONFIRMATION or CONFIRMED. If the confidence value associated with the smlNode specified by the Answer's XpathTrigger is less than or equal to the Answer's confirmationThreshold, the status of the semantic item is set to NEEDS_CONFIRMATION. Otherwise it is set to CONFIRMED. 3) Confirmation Processing: a) Examine at the sml document and search for XpathAcceptConfirms and XpathDenyConfirms. Set a global confirmation state to NEUTRAL (none was present), ACCEPT (xpathAcceptConfirms was present) or DENY (XPathDenyConfirms was present). In short-timeout confirmation, silence sets the confirmation state to ACCEPT. b) For all items to be confirmed, If there is a value in the sml document that matches the XpathTrigger of the confirm item If the new value is the same as the value to be confirmed, the item is confirmed Else, the item is set to the new value, and processed as an answer. c) If no Answer object is matched from the Answers or Confirms collections, If the confirmation state is CONFIRM Upgrade all items that need confirmation to confirmed. If the confirmation state is DENY Clear (empty) all items that need confirmation. Else, Mark all unmatched items that needed confirmation as confirmed. 24 Exceptions The following table lists the exceptions thrown by Speech Controls during render time. Attribute/Method/ Control/object Object Condition Exception QA SpeechIndex SpeechIndex <0 ArgumentOutOfRange Exception XpathDenyConfirms XpathDenyConfirms ArgumentNullException not specified if Confirm specified Answers Answers collection ArgumentException contains a non- answer object Prompt Prompt non- ArgumentNullException existant in Voice- only mode QA FirstInitialTimeout FirstInitialTimeout InvalidOperation specified Exception without Confirms being specified FirstInitialTimeout FirstInitialTimeout < ArgumentOutOfRange 0 Exception AcceptRejectThreshold AcceptRejectThreshold ArgumentOutOfRange <0 or >1 Exception DenyRejectThreshold DenyRejectThreshold ArgumentOutOfRange <0 or >1 Exception Command SpeechIndex SpeechIndex < 0 ArgumentOutOfRange Exception Scope Scope not valid ArgumentException Scope Scope not ArgumentNullException specified Type Type not specified ArgumentNullException Type/Scope More than 1 InvalidOperation Command of same Exception Type has same Scope AcceptCommandThreshold AcceptCommandThreshold ArgumentOutOfRange <0 or >1 Exception XpathTrigger XpathTrigger not ArgumentNullException specified AutoPostBack AutoPostBack is InvalidOperation true and Triggered Exception handler not specified AutoPostBack AutoPostBack is InvalidOperation false and Exception Triggered handler is specified CompareValidator SpeechIndex SpeechIndex < 0 ArgumentOutOfRange Exception SemanticItemToCompare one of InvalidOperation SemanticItemToCompare Exception and ValueToCompare is not specified ValueToCompare one of InvalidOperation SemanticItemToCompare Exception and ValueToCompare is not specified ValueToCompare ValueToCompare can InvalidOperation not be converted Exception to a valid Type. SemanticItemToValidate SemanticItemToValidate ArgumentNullException not specified CustomValidator SpeechIndex SpeechIndex < 0 ArgumentOutOfRange Exception SemanticItemToValidate SemanticItemToValidate ArgumentNullException not specified ClientValidation ClientValidationFunction ArgumentNullException Function not specified Answer XpathTrigger XpathTrigger not ArgumentNullException object specified for Answers or ExtraAnswwers ConfirmThreshold ConfirmThreshold ArgumentOutOfRange <0 or >1 Exception Reject Reject <0 or >1 ArgumentOutOfRange Exception AutoPostBack Answer.Triggered InvalidOperation has a handler but Exception Answer.AutoPostBack is false SemanticItem TargetElement TargetElement object specifies multiple ids TargetAttribute TargetAttribute is ArgumentNullException not specified when TargetElement is specified BindAt BindAt set to an ArgumentException invalid value BindAt BindAt is “server” ArgumentException and SemanticItem.Target Element is not a server-side control BindAt BindAt is “server” ArgumentException and SemanticItem.Target Attribute is not a member of the control specified by SemanticItem.Target Element BindAt BindAt is “server” ArgumentException and SemanticItem.Target Attribute is a member of SemanticItem.Target Element, but is not of type string, BindAt BindAt is “server” ArgumentException and SemanticItem.Target Attribute is a string, but is read-only. Reco object initialTimeout initialTimeout ArgumentOutOfRange negative Exception babbleTimeout babbleTimeout ArgumentOutOfRange negative Exception maxTimeout maxTimeout ArgumentOutOfRange negative Exception endSilence endSilence ArgumentOutOfRange negative Exception reject reject <0 or >1 ArgumentOutOfRange Exception Grammars Grammars ArgumentException collection contains a non- grammar object Params name not specified ArgumentNullException Params contains a non- ArgumentException param object Grammar src/InlineGrammar one of src or ArgumentNullException object InlineGrammar is not specified Prompt Params name not specified ArgumentNullException object Params contains a non- ArgumentException param object Dtmf object initialTimeout initialTimeout < 0 ArgumentOutOfRange Exception interdigitTimeout interdigitTimeout ArgumentOutOfRange <0 Exception endSilence endSilence < 0 ArgumentOutOfRange Exception Params name not specified ArgumentNullException Params contains a non- ArgumentException param object \ StyleSheet contains an object ArgumentException which is not a Style object Style object StyleReference StyleReference is ArgumentException invalid SmexMessageBase Timer Timer < 0 ArgumentOutOfRange Exception SmexMessage Message Message not ArgumentNullException specified MakeCall CalledDirectoryNumber CalledDirectoryNumber ArgumentNullException not specified 26 Terms and Defintions Term Definition Voice-only A mode of dialog that utilizes only speech input and ouput. There are no visual elements presented to the end user. Voice-only dialog typically implies the end user communication via the telephone. However, voice-only interaction may occur in a desktop computer setting. Multimodal A mode of dialog that utilizes speech input and visual ouput. Multimodal typically implies end user communication with a dialog via a hand-held computing device such as a pocket PC. Tap-and-talk A form of dialog interaction that utilizes speech input and visual ouput. This form of dialog interaction typically occurs on a hand-held computer such a pocket PC. The end user selects (“taps”) the visual element with a stylus or pen-like device and provides input to the visual element using speech (“talk”). Mixed A form of dialog interaction model, whereby the user Initiative is permitted to share the dialog initiative with the system, eg by providing more answers than requested by a prompt, or by switching task when not prompted to do so. SAPI SML SAPI Semantic markup language. The XML document returned by SAPI 6.0 when an utterance is determined to be in-grammar. (SAPI SML is a SAPI-specific return format. Speech tags interpreters are agnostic to the actual content format of the returned document, provided it is an XML document). SAPI SML contains semantic values, confidence scores and the words used by the speaker. (It is generated by script or XSLT instructions contained within the grammar rules.) SAPI SML is described in greater detail in the Speech Core document SML Generation . . . CSTA Computer Supported Telecommunications Applications - an ECMA standard. From the ECMA document: “CSTA is an interface that provides access to telecommunication functions that may be used with your phone (or many other communication devices) and may also be used by 3rd party applications such as Contact/Call Centres (e.g. ACD systems).” http://www.ecma.ch/ecma1/TOPICS/TC32/ TG11/CSTA.HTM System A form of dialog interaction model, whereby the system Initiative holds the initiative, and drives the dialog with typically simple questions to which only a single answer is possible. XPath XML Path language, a W3C recommendation for addressing parts of an XML document. See http://www.w3.org/TR/xpath. 27 Platform Parameter Settings The <param> mechanism (described in sections Error! Reference source not found. Prompt object contents, Error! Reference source not found. Reco object contents and Error! Reference source not found. Dtmf object contents)31 is used to configure platform settings. The following “params” are recognized by all Microsoft platforms: Object Name Value Default Description Prompt server URI http://localhost This configuration describing (client) setting selects the the location and registry speech server used for of the speech setting speech processing server (telephony server) bargein This The default The barge-in types are type attribute setting is defined as: speech: sets the type “speech”. If This represents of the platform speech/sound/energy recognition does not (“SOUND_START”) input event support the detected by the that the type recognition engine. browser uses selected, the grammar: This to determine browser represents the audio whether an defaults to partially matching the onbargein “speech”. recognition grammar. event should be fired. The speech server will generate a There are “PHRASE_START” event, three types and possibly a of semantic event (a bargeintype semantic property in that can be the phrase hypothesis set: has confidence greater “speech”, than the confidence “grammar” and threshold). The client “final”. decides when to throw “onbargein” based on the capabilities sent by the speech server when a session is opened. The confidence threshold used by the semantic event is a client platform setting. final: This represents using a “valid” final recognition result (i.e. a result where the utterance confidence level is above the “reject” threshold). Run in conjunction with multiple recognition mode, this represents the recognizer continuously listening for a valid result, for hotword/wake-up style scenarios. Note that in this case the browser must fire onbargein before firing onreco. Reco server URI http://localhost This configuration describing (client) setting selects the the location and registry speech server used for of the speech setting speech processing server (telephony server) 28 DET Descriptions The following table lists brief descriptions for each control, object and attribute. These descriptions will be used by the DET tool and exposed to the dialog author using Visual Studio. Control/object Attribute/Method/Object Brief description QA Id Programmatic name of the control SpeechIndex Activation order of the control ClientActivationFunction Client-side function used to determine whether or not to activate the QA control OnClientActive Client-side function called after QA is determined to be active OnClientComplete Client-side function called after execution of QA (successfully or not). OnClientListening Client-side function called after successful start of the reco object AllowCommands Whether or not Commands may be activated for this QA PlayOnce Whether or not this QA may be activated more than once per page XpathAcceptConfirms The path in the sml document that indicates the confirm items were accepted XpathDenyConfirms The path in the sml document that indicates the confirm items were denied FirstInitialTimeout Specifies initial timeout when QA. Count == 1. Answers An array of answer objects ExtraAnswers An array of answer objects Confirms An array of answer objects. Prompt The Prompt object for this QA Reco The Reco object for this QA Dtmf The Dtmf object for this QA Command Id Programmatic name of the control SpeechIndex Activation order of the control Scope The id of ASP.NET control that activates this Command grammar Type The type of this Command in order to allow the overriding of identically typed commands XpathTrigger SML document path that triggers this command AcceptCommandThreshold Confidence level of recognition that is necessary to trigger this command OnClientCommand Function to execute on recognition of this Command's grammar AutoPostBack Whether or not Command control posts back to server when Command grammar is recognized. Prompt A Prompt object Grammar The grammar object which will listen for the command Dtmf The Dtmf object which will activate the command CompareValidator Id Programmatic name of the control SpeechIndex Activation order of the control Type Sets the datatype of the comparison ElementToCompare The JScript variable or Id of the SemanticItem used as the basis for the comparison SemanticItemToValidate The Id of the control that is being validated SemanticItemToCompare The Id of the control that is the basis for comparison Operator Validation operator InvalidateBoth Whether or not to invalidate both ElementToCompare and ElementToValidate Prompt Prompt to indicate the error CustomValidator id Programmatic name of the control SpeechIndex Activation order of the control SemanticItemToValidate The Id of the control that is being validated AttributeToValidate Attribute of the ElementToValidate that contains the value being validated ClientValidationFunction Validation function Prompt Prompt to indicate the error Answer id Programmatic name of the object object XpathTrigger The part of the SML document this answer refers to ClientNormalizationFunction Function that returns author- specified transformation of the recognized item SemanticItem The semantic item to which this answer should be written ConfirmThreshold The minimum confidence level of recognition necessary to mark this item as confirmed Reject Rejection threshold for the Answer OnClientAnswer Function to be called when the XpathTrigger is matched AutoPostBack Whether or not to post back to the server each time user interacts with the control Prompt id Programmatic name of the object object type Mime-type corresponding to the speech output format prefetch Whether or not the prompt should be immediately synthesized and cached at browser when the page is loaded lang The language of the prompt content bargein Whether or not the speech platform is responsible for stopping prompt playback when speech or DTMF input is detected. PromptSelectFunction Function that selects and/or modifies a prompt string prior to playback OnClientBookmark Function which is called when a bookmark is reached in the prompt text during playback OnClientError Function called in response to an error event in the client InLinePrompt Text of the prompt Params Specifies non-standard speech platform configuration values Reco object Id Programmatic name of the object StartElement Name of the GUI element to throw the start event StartEvent Name of the GUI event that will activate the underlying client-side Reco object StopElement Name of the GUI element to throw the stop event StopEvent Name of the GUI event that will deactivate the underlying client-side Reco object initialTimeout The time in milliseconds between start of recognition and the detection of speech babbleTimeout The period of time in milliseconds in which the recognizer must return a result after detection of speech maxTimeout The period of time in milliseconds between recognition start and results returned to the browser endSilence Period of silence in milliseconds after the end of an utterance which the recognition results are returned Reject The rejection threshold below which the platform will throw the noReco event Lang The language of the speech recognition engine Mode Specifies the recognition mode to be followed GrammarSelectFunction Client-side function called prior to starting the recognition process OnClientSilence Client-side function that will be called after detecting silence OnClientNoReco Client-side function that will be called after detecting no recognition OnClientError Client-side function that will be called after recognition errors OnClientSpeechDetected Client-side function called when recognition platform detects speech Grammars An array of grammar objects. Params Specifies non-standard speech platform configuration values Record Used for recording audio input from the user. Grammar id Programmatic name of the object type Mime-type of the grammar format used lang Language of the grammar src URI of the grammar to load InLineGrammar Text of the grammar Dtmf object id Programmatic name of the object numDigits Number of key presses required to end the DTMF collection session autoflush Whether or not to automatically flush the DTMF buffer on the underlying telephony interface card before activation terminalChar Terminating key to end the DTMF collection session initialTimeout Number of milliseconds to wait between activation and the first key press before raising a timeout event interdigitTimeout Number of milliseconds to wait between key presses before raising a timeout event SMLContext DTMF results wrapped in SML tags OnClientSilence Function that executes if there is no DTMF key press before initialTimeout expires OnClientKeyPress Function that executes on every pressing of a legal DTMF key. OnClientError Function that executes if serious or fatal error occurs with the DTMF collection/recognition process Params Params Specifies non-standard DTMF engine configuration values name The name of the parameter to be configured. record Value The value assigned to the named parameter enabled Whether or not to record user input. type MIME type of the file containing the recorded audio. Whether or not to play a beep before recording begins. Appendix C Overview 1 Design Principles Application Controls are a means to wrap common speech scenarios in one control. Application Controls must work both in multi-modal and voice-only modes, except for the Navigator control which is a voice-only control. Application Controls are “companions” to the visual controls. As such they may not have all the properties that are needed to run a full application. It is likely that the authors will need to get some pieces of information directly from the visual controls. Application controls include a set of default prompts to facilitate rapid design. Not all prompts are included; in such cases authors must provide a prompt that makes sense in the context of the application. It is recommended that authors use the prompt editor to create professional, topical prompts before deploying their application. Application controls do not currently have a styleref property. This feature will be added for M4. 2 Design Details All controls should derive from ApplicationControl or BasicApplicationControl. They inherit from SpeechControlBase and implement INamingContainer. Although not required, all controls will, as much as possible, follow a common coding framework: 1. Internal QA's are created in the CreateChildControls methods. 2. Script is rendered by overriding ISpeechRender.RenderSpeechHtml and SpeechRender.RenderSpeechScript. 3. Every control outputs a jscript object to the page. This object contains information related to the control. In particular all built-in functions are part of this object in order to minimize name clashes. 4. All built-in javascript functions are included in a javascript file and not in C#. Prompt related functions are put in a file called ControlName-prompt.js. All other functions are put in a file called ControlName-code.js. 5. The built-in prompt and grammar libraries are loaded from resources to allow localization. Only the names of the libraries are in the resources. The prompts and grammars themselves are in the libraries. 3 Deployment Application controls will be deployed in a separate dll to the WebServer. Application controls might have extra script files, also deployed to the webserver. Application controls will be added to the GAC, and will be available through the Toolbar in VisualStudio. Namespace: Microsoft.Web.UI.Speech.ApplicationControls Dll: Microsoft.Web.UI.Speech.ApplicationControls.dll Script: %SystemDrive%\Inetpub\wwwroot\aspnet_speech\client_script\en-US\*.js Grammar %SystemDrive%\Inetpub\wwwroot\aspnet_speech\client_script\en-US\ 1 Common Attributes Application controls derive from one of two base classes. These classes are public and developers of application controls should inherit from them. The first base class contains a minimal set of properties that the application controls should support. The second class contains a richer set of properties. Application controls should, if possible, support this richer set. Most application controls will support extra properties that are not included in the base classes because of they are specific to each control. The two base classes are described below. Some common extra properties are also mentioned. All application controls derive from SpeechControlBase and inherit all its members. All application controls also implement INamingContainer. The inherited members are not listed here. 1.1 BasicApplicationControl This class is abstract. It inherits from SpeechControlBase and INamingContainer. public class abstract BasicApplicationControl : IndexedSpeechControl { bool AllowCommands{get; set;}; int BabbleTimeout{get; set;}; bool Bargein{get; set;}; string CarrierGrammarUrl{get; set;}; string ClientActivationFunction{get; set;}; int EndSilence{get; set;}; int InitialTimeout{get; set;}; int MaxTimeout{get; set;}; string OnClientActiveFirst{get; set;}; string OnClientCompleteLast{get; set;}; string PostAnswerCarrierRule{get; set;}; string PreAnswerCarrierRule{get; set;}; string PromptSelectFunction{get; set;}; string QuestionPrompt{get; set;}; string PromptDatabase{get; set;}; } 1.1.1 BasicApplicationControl Properties AllowCommands Optional. Only used in voice-only mode. Default: true. This property is passed in to all relevant internal QA controls created by this control. BabbleTimeout Optional. Used in both multimodal and voice-only modes. Default is 0. This property is passed in to all the relevant internal QA controls created by this control. An exception will be thrown for negative values of BabbleTimeout. Bargein Optional. Only used in voice-only mode. Default: true. Specifies or not the playback of the prompt may be interrupted by the human listener. This property is passed in to all the relevant internal QA controls created by this control. CarrierGrammarUrl Optional. Used in both multimodal and voice-only modes. Default: “ ” URL for the carrier grammar. This grammar contains carrier phrases such as “I would like” or “please” which may be used by the user but do not contain semantic information. An exception will be thrown if a PreAnswerCarrierRule, PostAnswerCarrierRule, PreConfirmCarrierRule, or PostConfirmCarrierRule is specified and CarrierGrammarUrl is not specified. ClientActivationFunction Optional. Only used in voice-only mode. Default: “ ”. Client-side function used to determine whether or not to activate the QAs in this application control. This property is passed in to all the relevant internal QA controls created by this control. EndSilence Optional. Used in both multimodal and voice-only modes. For Reco objects in “automatic” mode, the period of silence in milliseconds after the end of an utterance which must be free of speech after which the recognition results are returned. Ignored for Recos of modes other than “automatic”. If not specified, defaults to platform internal value. An exception will be thrown for negative values. InitialTimeout Optional. Used in both multimodal and voice-only modes. No default value. This property is passed in to all the relevant internal QA controls created by this control. An exception will be thrown for negative values of InitialTimeout. MaxTimeout Optional. Used in both multimodal and voice-only modes. Default is 0. This property is passed in to all the relevant internal QA controls created by this control. An exception will be thrown for negative values of MaxTimeout. OnClientActiveFirst Optional. Used only in voice-only mode. Default: “ ”. Name of a function called when the first QA control of the application control gets activated. OnClientActiveFirst returns no values. The signature for OnClientActiveFirst is: function onClientActiveFirst(string eventsource, string lastCommandOrException, int Count, object SemanticItemList) where: eventsource is the id of the object (specified by Reco.StartEvent) whose event started the Reco associated with the QA (for multimodal). eventsource will be null in voice-only mode. lastCommandOrException is a Command type (e.g., “Help”) or a Reco event (e.g., “Silence” or “NoReco”) for voice-only mode. lastCommandOrException is the empty string for multimodal. See Speech Controls Functional Specification for more information on the lastCommandOrException parameter. Count is the number of times the first activated QA has been activated. Count is always 1. SemanticItemList is an associative array that maps semantic item id to semantic item objects. OnClientCompleteLast Optional. Used in both multimodal and voice-only modes. Default: “ ”. Name of a function called when the last QA control of the application control is completed. OnClientCompleteLast returns no values. The signature for OnClientCompleteLast is: function onClientCompleteLast(string eventsource, string lastCommandOrException, int Count, object SemanticItemList) where: eventsource is the id of the object (specified by Reco.StartEvent) whose event started the Reco associated with the QA (for multimodal). eventsource will be null in voice-only mode. lastCommandOrException is a Command type (e.g., “Help”) or a Reco event (e.g., “Silence” or “NoReco”) for voice-only mode. lastCommandOrException is the empty string for multimodal. See Speech Controls Functional Specification for more information on the lastCommandOrException parameter. Count is the number of times the last QA has been activated consecutively. Count is always 1 in voice-only and zero in multimodal. SemanticItemList is an associative array that maps semantic item id to semantic item objects. PostAnswerCarrierRule Optional. Used in both multimodal and voice-only modes. Default: “ ” Name of the rule in the carrier grammar that contains carrier phrases used after providing an answer (e.g., “please”). An exception will be thrown if a PreAnswerCarrierRule is specified and CarrierGrammarUrl is not specified. PreAnswerCarrierRule Optional. Used in both multimodal and voice-only modes. Default: “ ” Name of the rule in the carrier grammar that contains carrier phrases used before providing an answer (e.g., “I would like”). An exception will be thrown if a PostAnswerCarrierRule is specified and CarrierGrammarUrl is not specified. PromptSelectFunction Optional. Only used in voice-only mode. Specifies a client-side function that allows authors to select and/or modify a prompt string prior to playback. The function returns the prompt string. PromptSelectFunction is called once the QA has been activated and before the prompt playback begins. The signature for PromptSelectFunction is as follows: String PromptSelectFunction(string lastCommandOrException, int Count, object SemanticItemList, string QA, object AppControlData) where: lastCommandOrException is a Command type (e.g., “Help”) or a Reco event (e.g., “Silence” or “NoReco”). See Speech Controls Functional Specification for more information on the lastCommandOrException parameter. Count is the number of times the QA has been activated consecutively. Count starts at 1 and has no limit. See Speech Controls Functional Specification for more information on the Count parameter. SemanticItemList is an associative array that maps semantic item id to semantic item objects. QA is a coded name for the current active QA (e.g., “question”, “confirm”). AppControlData contains information pertaining to the application control. Controls contain built-in prompts for question, confirm, silence, noreco and help. The default behavior is to play the silence, noreco or help prompt if appropriate followed by the question or confirm prompt. If the PromptSelectFunction returns null, the default prompt will be played. QuestionPrompt Only used and required in voice-only mode. No default. Text of the initial question to be played (e.g., “How many pizzas do you want?”). PromptDatabase Optional. Only used in voice-only mode. Default: “ ” Name of the prompt database. 1.2 ApplicationControl This class is abstract. It inherits from BasicApplicationControl. public class abstract ApplicationControl : BasicApplicationControl { bool AutoPostback{get; set;}; float ConfirmThreshold{get; set;}; float ConfirmRejectThreshold{get; set;}; EventHandler CompleteLast; int FirstInitialTimeout{get; set;}; string Mode{get; set;}; string OnClientActive{get; set;}; string OnClientComplete{get; set;}; string OnClientListening{get; set;}; string PostConfirmCarrierRule{get; set;}; string PreConfirmCarrierRule{get; set;}; float RejectThreshold{get; set;}; sting StartElement{get; set;}; string StartEvent{get; set;}; sting StopElement{get; set;}; string StopEvent{get; set;}; } 1.2.1 ApplicationControl Properties AutoPostback Optional. Used in both multimodal and voice-only modes. Default is false. If true, the control fires the CompleteLast event immediately after OnClientCompleteLast has executed. If AutoPostback is false the control fires the CompleteLast event when the next post back occurs. An exception will be thrown if AutoPostback is true and CompleteLast is not specified. ConfirmThreshold Optional. Used only in voice-only mode. The minimum confidence level of recognition necessary to mark an item as confirmed. Legal values are 0-1. Default: 1, i.e., by default confirmation is always performed. This property is passed in to all the internal QA controls created by this control. An exception will be thrown for out of range values. ConfirmRejectThreshold Optional. Used only in voice-only mode. Legal values are 0-1. The ConfirmRejectThreshold is the threshold above which accept/denial confidence needs to be in order to accept the accept or deny. This threshold is usually higher than the RejectThreshold which applies to all other answers. This property is passed in to all the relevant internal confirm answer elements created by this control. An exception will be thrown for out of range values. CompleteLast Optional. Used in both multimodal and voiced-only modes. Default: null. Specifies a server-side function to be executed when the CompleteLast event is fired. The CompleteLast event is fired after the OnClientCompleteLast function has executed if AutoPostback is true. If AutoPostback is false, the CompleteLast event is fired at the next post back. Mode Optional. Used in both multimodal and voice-only modes. Default is “automatic”. Specifies the recognition mode to be followed. Legal values are “automatic”, “single”, and “multiple”. See the mode property of the Reco object in the Speech Control spec for more information. OnClientActive Optional. Used in both multimodal and voice-only modes. Default: “ ”. This property is passed in to all the relevant internal QA controls created by this control. The OnClientActive function does not return values. The signature for OnClientActive is as follows: function OnClientActive(string eventsource, string lastCommandOrException, int Count, object SemanticItemList) where: eventsource is the id of the object (specified by Reco.StartEvent) whose event started the Reco associated with the QA (for multimodal). eventsource will be null in voice-only mode. lastCommandOrException is a Command type (e.g., “Help”) or a Reco event (e.g., “Silence” or “NoReco”) for voice-only mode. lastCommandOrException is the empty string for multimodal. See Speech Controls Functional Specification for more information on the lastCommandOrException parameter. Count is the number of times the current QA has been activated consecutively. Count starts at 1 and has no limit for voice-only mode. Count is zero for multimodal. See Speech Controls Functional Specification for more information on the Count parameter. SemanticItemList For voice-only mode, SemanticItemList is an associative array that maps semantic item id to semantic item objects. For multimodal, SemanticItemList will be null. OnClientComplete Optional. Used in both multimodal and voice-only modes. Default: “ ”. This property is passed in to all the internal QA controls created by this control. The onClientComplete function does not return values. The signature for onClientComplete is as follows: function onClientComplete (string eventsource, string lastCommandOrException, int Count, object SemanticItemList) where: eventsource is the id of the object (specified by Reco.StopEvent) whose event stopped the Reco associated with the QA (for multimodal). eventsource will be null in voice-only mode. lastCommandOrException is a Command type (e.g., “Help”) or a Reco event (e.g., “Silence” or “NoReco”) for voice-only mode. lastCommandOrException is the empty string for multimodal. See Speech Controls Functional Specification for more information on the lastCommandOrException parameter. Count is the number of times the current QA has been activated consecutively. Count starts at 1 and has no limit for voice-only mode. Count is zero for multimodal. See Speech Controls Functional Specification for more information on the Count parameter. SemanticItemList For voice-only mode, SemanticItemList is an associative array that maps semantic item id to semantic item objects. For multimodal, SemanticItemList will be null. OnClientListening Optional. Used in both multimodal and voice-only modes. Default: “ ” This property is passed in to all the internal QA controls created by this control. The function does not return any values. The signature for OnClientListening is as follows: function OnClientListening(string eventsource, string lastCommandOrException, int Count, object SemanticItemList) where: eventsource is the id of the object (specified by Reco.StartEvent) whose event started the Reco associated with the QA (for multimodal). eventsource will be null in voice-only mode. lastCommandOrException is a Command type (e.g., “Help”) or a Reco event (e.g., “Silence” or “NoReco”) for voice-only mode. lastCommandOrException is the empty string for multimodal. See See Speech Controls Functional Specification for more information on the lastCommandOrException parameter. Count is the number of times the current QA has been activated consecutively. Count starts at 1 and has no limit for voice-only mode. Count is zero for multimodal. See Speech Controls Functional Specification for more information on the Count parameter. SemanticItemList For voice-only mode, SemanticItemList is an associative array that maps semantic item id to semantic item objects. For multimodal, SemanticItemList will be null. Note: OnClientListening is not called in the last QA of each Application Control. PostConfirmCarrierRule Optional. Only used in voice-only mode. Default: “ ”. Name of the rule in the carrier grammar that contains carrier phrases used after providing a correction. An exception will be thrown if a PostConfirmCarrierRule is specified and CarrierGrammarUrl (inherited from the BasicApplicationControl class) is not specified. PreConfirmCarrierRule Optional. Only used in voice-only mode. Default: “ ”. Name of the rule in the carrier grammar that contains carrier phrases used before providing a correction. An exception will be thrown if a PostConfirmCarrierRule is specified and CarrierGrammarUrl (inherited from the BasicApplicationControl class) is not specified. RejectThreshold Optional. Used in both multimodal and voice-only modes. Legal values are 0-1. Default: 0. An exception will be thrown for out of range values. This property is passed in to all the internal QA controls created by this control. StartElement Optional. Used only in multimodal mode. Default is “ ”. Specifies the id of the visual control that fires the StartEvent. StartEvent Optional. Used only in multimodal mode. Default: “ ”. Name of the event that starts recognition in multimodal mode, e.g. “onmousedown”. An exception will be thrown if StartEvent is specified and StartElement is not. StopElement Optional. Used only in multimodal mode. Default is “ ”. Specifies the id of the visual control that fires the StopEvent. StopEvent Optional. Used only in multimodal mode. Default: “ ”. Name of the event that stops recognition in multimodal mode, e.g., “onmouseup”. An exception will be thrown if StopEvent is specified and StopElement is not. FirstinitialTimeout Optional. Only used in voice-only mode. Default: 800. This property is passed in to all the relevant internal QA controls created by this control. If set to 0, QA controls that use short time-out confirmation will revert to using explicit confirmation. An exception will be thrown for negative values of FirstInitialTimeout. 1.3 Other Properties Application Controls dealing with numbers should also support DTMF. Application Controls that support DTMF must inherit from the IDTMF interface. The IDTMF interface contains the following method: bool AllowDTMF {get; set;} Optional. Only used in voice-only mode. Default: true. If set to true, the controls allow DTMF input. If set to false, DTMF inputs are not allowed. 1.4 Operation 1.4.1 Execution Flow Each control needs to confirm values as appropriate. Confirmation of digit inputs: When getting a series of digits that can be split into specific places (e.g., groups of 4 digits for a credit card number, groups of 3, 2 and 4 for a social security number, groups of 5 and 4 for a zipcode number), the control will allow users to stop at those places. If users stop, then the control will immediately try to confirm the digits given so far. Confirmation will be done by a short timeout confirmation of each group. Users can accept (by either saying yes or staying silent), deny or correct the value. They cannot provide more digits at this point. If a denial is made, the control tries to get and confirm the new value immediately. If a correction is made, the control tries to confirm the new value immediately. Once all digits are confirmed, the control will ask for more if users did not provide them already. If the digits given by the user do not need confirmation because they have been recognized with high enough confidence, the control will prompt users to go on (“Go on”). If DTMF is allowed, users can accept the digits by pressing the pound (#) sign. They can also correct by entering the series of digits again. Users cannot deny using DTMF. There is no way to cancel or exit out of an Application Control (except the Navigator control) without the author providing a Command control that implements the functionality. 1.4.2 Prompting Prompts in all Application Controls behave the same way. The question and confirm prompts are control-specific based on properties set in the control. The Help prompt for each control consists of a control-specific help message followed by either the value of the QuestionPrompt property or a replay of the confirmation prompt-depending on progress of dialog flow. When the Application Control is not able to recognize user input, the control will issue a noreco prompt followed by either the value of the QuestionPrompt property or a replay of the confirmation prompt-depending on progress of dialog flow. When the control detects silence, the control will issue a silence prompt followed either by the value of the QuestionPrompt property or a replay of the confirmation prompt-depending on progress of dialog flow. 1.4.3 Default Grammars The grammars built-in the controls are based on the common grammar library. 2 IDTMF Interface Controls that support DTMF must inherit from this interface. interface IDTMF { bool AllowDTMF{get; set;}; int InterDigitTimeout{get; set;}; string OnClientKeyPress{get; set;}; bool PreFlush{get; set;}; } 2.1 IDTMF Properties AllowDtmf Required. Determines whether to support DTMF input. InterDigitTimeout Required. Determines the timeout between keypresses. PreFlush Required. Determines whether to automatically flush the DTMF buffer on the underlying telephony interface card before activation. OnClientKeyPress The name of the client-side event that will be fired each time a key is pressed. There are two more properties include: int InitialTimeout {get; set;} int EndSilence {get; set;} which are provided in BasicApplicationControl Properties. 3 SingleItemChooser Control The SingleItemChooser control allows users to select one item from a list of items. The grammar for selecting the item is created on the fly based on the data from the list. class SingleItemChooser : ApplicationControl { object DataSource{get; set;}; string DataMember{get; set;}; string DataTextField{get; set;}; string DataBindField{get; set;}; ITemplate GrammarTemplate{get; set;}; string PromptSelectFunction{get; set;}; string SemanticItem{get; set;}; } 3.1 SingleItemChooser Properties Common properties are described above. DataSource Required. Used in both multimodal and voice-only modes. Use the DataSource property to specify the source of values to bind to the SingleItemChooser control. An exception will be thrown if DataSource is not specified. The DataSource property is the same as used in other ASP.NET controls. See ASP.NET documentation for more information on the DataSource property. DataMember Optional. Used in both multimodal and voice-only modes. Default is null. A data member from a multimember data source. Use the DataMember property to specify a member from a multimember data source to bind to the list control. For example, if you have a data source, with more than one table, specified in the DataSource property, use the DataMember property to specify which table to bind to a data listing control. Note on databinding: The resolved data source (datasource and datamember) must be of one of the following types: Array Implementer of IList, provided the implementer has a strongly typed Item property (that is, the Type is anything but Object). You can accomplish this by making the default implementation of Item private. If you want to create an IList that follows the rules of a strongly typed collection, you should derive from CollectionBase. Implementer of ITypedList. The DataMember property is the same as used in other ASP.NET controls. See ASP.NET documentation for more information on the DataMember property. DataTextField Required. Used in both multimodal and voice-only modes. Default is null. A System.String that specifies the field of the data source that provides the grammar for each individual item on the list. The string is a comma-separated list of synonyms. Each synonym is a possible way of selecting a value. An exception is thrown if this property is specified but the data source does not contain a corresponding column. An exception is thrown if a synonym can be used to select more than one value. DataBindField Required. Used in both multimodal and voice-only modes. Default is null. A string that specifies the field of the data source that provides the binding values of the list items. If this property is specified but the data source does not contain a corresponding column, an exception is thrown. GrammarTemplate Optional. Used in both multimodal and voice-only modes. Default is null. If specified, the template is used to fill in the grammar that will be used for recognition. Each call to the template must return a comma delimited string of terms. Each of the terms is a possible way of saying the value. Calls are made with the data obtained from the source. PromptSelectFunction Optional. Only used in voice-only mode. The QA parameter passed to this function may be either: “question”, “confirm”, or “acknowledge”. See Section 1.1.1 BasicApplicationControl Properties for a description of the PromptSelectFunction and its parameters. SemanticItem Required. Used in both multimodal and voice-only modes. The ID of the semantic item receiving the value of the chosen item. The index of the selected item in the list will be added to the expando properties of the semantic item as “index”. The spokenText expando property of the SemanticItem will be set to the spoken text used by the user to select the item. An exception will be thrown if SemanticItem is not specified or if it is not a valid semantic item, e.g., the id does not correspond to an element on the page or it corresponds to an element that is not a semantic item. 3.2 Client-Side Object Array AvailableOptions {get;} Array of all the choices that can be spoken by the user (not including synonyms). 3.3 Mark-Up <speech:SingleItemChooser id=”...” SpeechIndex=”...” AllowCommands=”...” BabbleTimeout=”...” BargeIn=”...” CarrierGrammarUrl=”...” ClientActivationFunction=”...” EndSilence=”...” InitialTimeout=”...” MaxTimeout=”...” OnClientActiveFirst=”...” OnClientCompleteLast=”...” PostAnswerCarrierRule=”...” PreAnswerCarrierRule=”...” PromptSelectFunction=”...” QuestionPrompt=”...” PromptDatabase=”...” AutoPostback=”...” ConfirmThreshold=”...” ConfirmRejectThreshold=”...” CompleteLast=”...” Mode=”...” OnClientActive=”...” OnClientComplete=”...” OnClientListening=”...” PostConfirmCarrierRule=”...” PreConfirmCarrierRule=”...” RejectThreshold=”...” StartElement=”...” StartEvent=”...” StopElement=”...” StopEvent=”...” SemanticItem=”...” DataSource=”...” DataMember=”...” DataTextField=”...” DataBindField=”...” runat=“server”> <GrammarTemplate> ... </GrammarTemplate> </speech:SingleItemChooser> 3.4 Operation 3.4.1 Execution Flow In voice only mode, the control execution follows the following flow: SpeechIndex QA 1 Confirm 2 Question 3 Done In multimodal mode, the start event starts recognition for a single item and binds the value as in voice-only mode. If the DataSource contains no items from which to choose, the control does not render. 3.4.2 Default Prompts The default prompts are: Question QA Question: Must be specified by user or an error will be returned. Help: “Please tell me one of the following choices”+(list of items)+Question Confirm QA Question: “Did you say”+SemanticItem.spokenText+? Help: “Please say yes or no, or tell me the correct choice”+SemanticItem.spokenText+? Also, if short timeout confirmation is allowed, i.e., FirstInitialTimeout >0, the prompt is: SemanticItem. spokenText+? Done QA Prompt:“ ” All QA controls Silence: “I didn't hear you.” NoReco: “I didn't understand you.” 3.4.3 Default Grammar The default grammar will list in parallel all the objects in the data source. The control will put the binding value corresponding to the recognized value into the target element attribute. The grammar can be expanded by providing a comma separated list of synonyms rather than a single element. Users can then select the list items by using any of the synonym names. If the synonym list contains duplicates an exception is thrown. Authors can override the default grammar by providing a grammar template. This template is called with the data contained in the data source. This data can be used to create a specific grammar. Here is an example to allow users to refer to a person in different ways, e.g., “Nancy”, “Davolio”, “Nancy Davolio”, assuming the data source contains a FirstName and LastName column: <grammarTemplate> <%# DataBinder.Eval(Container.DataItem, “LastName”) %>, <%# DataBinder.Eval(Container.DataItem, “FirstName”) %>, <%# DataBinder.Eval(Container.DataItem, “FirstName”) %><%# DataBinder.Eval(Container.DataItem, “LastName”) %> </grammarTemplate> Here is an example to fetch the grammar from a resource, assuming that a resource manager has been initialized and the data source contains a LastName column: <grammarTemplate> <%# ResourceManager.GetString(DataBinder.Eval(Container.DataItem, “LastName”)) %> </grammarTemplate> 3.4.4 Default Commands Default Help The default help will present the choices available to the users. In order to activate help, the author needs to create a command of type ‘Help’ whose scope contains the application control. If the author provides a prompt in the Command control, the prompt in the Command control will be played before the default prompt. 3.4.5 Example control: Choose a topping User: Pepperoni control: Choose a topping User: Help control: You can choose from Pepperoni, Cheese and Anchovies. Choose a topping. User: Pepperoni 3.5 Future Features The following features will be considered for V2 of the Microsoft NET Speech SDK. 3.5.1 Spelling When choosing an item by speaking does not work well, e.g., choosing names may, we could fallback to a spelling mode. 3.5.2 Repeated Entries We do not currently allow repeated entries in the datasource. We may want to investigate how these could be accepted and disambiguated. 4 DataTableNavigator Control This is a Voice-Only control. The DataTableNavigator control will allow users to navigate though a table of caption/content elements. class DataTableNavigator : BasicApplicationControl { long ShortInitialTimeout{get; set;}; object DataSource{get; set;}; string DataMember{get; set;}; StringArrayList DataHeaderFields{get; set;}; StringArrayList DataContentFields{get; set;}; bool DisableColumnNavigation{get; set;}; ITemplate HeaderTemplate{get; set;}; ITemplate ContentTemplate{get; set;}; TemplateCollection Columns {get; set;}; ITemplte GrammarTemplate { get; set; } string PromptSelectFunction{get; set;}; AccessMode AccessMode { get; set; } SemanticItem SemanticItem { get; set; } GrammarCollection Grammars { get; set; } } enum AccessMode { Fetch, Select, Ignore }; 4.1 DataTableNavigator Properties Common properties are described above. ShortinitialTimeOut Optional. Default: 1200 Time in milliseconds before OnSlience is fired. If greater than 0, automatic navigation is on and OnSlience navigates to the next row of available data. If set to 0, automatic navigation is turned off. An exception will be thrown if ShortInitialTimeout is a negative value. AccessMode Optional. Default: AccessMode.Fetch Allows the user to configure the DataTableNavigator to browse to, fetch and exit, and ignore an item in the data set spoken by the user. This behavior is determined by the following options: AccessMode.Ignore: The stated name is ignored, and the no reco prompt is played. AccessMode.Select: If this flag is set then the Navigator builds a grammar out of the elements in the header. It does this using exactly the same mechanism as the ListSelector i.e. allowing the author to use a grammar template to indicate synonyms and also throwing an exception when duplicate entries are detected. When the user speaks a name in the first column the effect is to go to the 1st column entry for that name and behave as through we had navigated there by any other means i.e. read the entry out. Following this the the Navigator will ask the ‘next command?’ question, regardless of whether it has been configured to treat Silence as Next. The theory here is that the user definitely wants to do something with the item that they have requested by name. AccessMode.Fetch: If this flag is set then the Navigator builds a grammar out of the elements in the header. It does this using exactly the same mechanism as the ListSelector i.e. allowing the author to use a grammar template to indicate synonyms and also throwing an exception when duplicate entries are detected. When the user speaks a name in the first column the effect is to exit the Navigator, setting the sem item with the row index of the recognized 1st column name. SemanticItem Required. Contains the row index of value spoken by the user. Grammars Optional. Default is the built-in grammar described in section 4.4.3. Allows the user to configure the grammar supported by the built-in commands. If a grammar tag is absent, the command will not be supported by the control. If a grammar tag is presented but missing a “src” attribute, the default grammar will be used. DataSource Required. Use the DataSource property to specify the source of values used by the Navigator control. An exception will be thrown if DataSource is not specified. The DataSource property is the same as used in other ASP.NET controls. See ASP.NET documentation for more information on the DataSource property. DataMember Optional. Default is null. A data member from a multimember data source. Use the DataMember property to specify a member from a multimember data source to bind to the DataTableNavigator control. Implementer of ITypedList. The DataMember property is the same as used in other ASP.NET controls. See ASP.NET documentation for more information on the DataMember property. DataHeaderFields Required. The control will concatenate the content of all the header fields to create the header prompts. DataContentFields Required. The control will concatenate the content of all the content fields to create the content prompts. For example, assume a DataSource that contains weather information as in the following table: DataHeaderFields DataContentFields Seattle Washington 53 75 Clear Spokane Washinton 68 87 Clear Yakima Washinton 67 89 Partly Cloudy When the user navigates to the first row of data, the control will prompt the user with “Seattle, Wash.”. If the user issues the command “Read”, the control will prompt the user with the low and high temperatures and the sky conditions. DisableColumnNavigation Optional. Default: false. If true, name of columns are not added to the grammar. Only the value of the DataHeader is played. HeaderTemplate Optional. Default: null. Gets or sets the template that defines how the headers are played. The way headers are read can be changed by specifying a template. The following example shows how to change the header to play a prompt like ‘Employee number ID’. <HeaderTemplate> Employee number <%# DataBinder.Eval(Container.DataItem, “EmployeeID”) %> </HeaderTemplate> ContentTemplate Optional Default: null Gets or sets the template that defines how the contents are played. The way contents are read can be changed by specifying a template. The following example shows how to change the header to play a prompt like ‘Employee number ID is Name’. <ContentTemplate> Employee number <%# DataBinder.Eval(Container.DataItem, “EmployeeID”) %> is <%# DataBinder.Eval(Container.DataItem, “LastName”)%> </ContentTemplate> Columns Optional. Default: null. Collection of ColumnTemplate objects. Each ColumnTemplate object allows the specification of the prompt that will be played if the user requests that column. The following example shows this for the Title column: <columns> <column name=‘Title’> <contentTemplate> The title of <%# DataBinder.Eval(Container.DataItem, “LastName”) %>is <%# DataBinder.Eval(Container.DataItem, “Title”) %> </contentTemplate> </column> </columns> ColumnTemplate's properties are: string Name {get; set;} Default: “ ” Name of the column ITemplate ContentTemplate {get; set;} Default: null Template used to create the prompt for that column PromptSelectFunction Optional. The QA parameter passed to this function is always “question”. The lastCommandOrException argument will take the following values (in addition to the values listed in the description of lastCommandOrException in the Speech Controls Functional Specification): NVG_previousOnFirstError when trying to get an item before the first one; NVG_nextOnLastError when trying to get an item after the last one; NVG_onlyItemError. This error message replaces NVG_previousOnFirstError and NVG_nextOnLastError when there is only one item in the datasource. NVG_headers when requested to read the headers; NVG_contents when requested to read the contents; NVG_column when requested to read a specific column name. The name of the column to read is put in the Arg property of the AppControlData object passed in to the PromptSelectFunction associated with this control. See Section 1.1.1 BasicApplicationControl Properties for a description of the PromptSelectFunction and its parameters. 4.2 Client-Side Object The client-side object contains the following properties: int Index {get;} Index of the current item. The index is zero-based. int Max {get;} Total number of items in the data. Array[ ][ ] DataTable {get;} Table containing the data element. Data[column] [index] contains the Data in column ‘column’ and row ‘index’. string PreviousCommandOrException {get;} Name of the command or exception before last. Required to deal with repeats successfully. string Arg{get;} Name of the column to play when lastCommandOrException is NVG_column. 4.3 Mark-Up <speech:DataTableNavigator id=“ . . . ” SpeechIndex=“ . . . ” AllowCommands=“ . . . ” BabbleTimeout=“ . . . ” BargeIn=“ . . . ” CarrierGrammarUrl=“ . . . ” ClientActivationFunction=“ . . . ” EndSilence=“ . . . ” InitialTimeout=“ . . . ” MaxTimeout=“ . . . ” OnClientActiveFirst=“ . . . ” OnClientCompleteLast=“ . . . ” PostAnswerCarrierRule=“ . . . ” PreAnswerCarrierRule=“ . . . ” PromptSelectFunction=“ . . . ” QuestionPrompt=“ . . . ” PromptDatabase=“ . . . ” InitialShortTimeout=“ . . . ” DataSource=“ . . . ” DataMember=“ . . . ” DataHeaderFields=“ . . . ” DataContentFields=“ . . . ” DisableColumnNavigation=“ . . . ” SelectBehaviorMode=“ . . . ” PromptSelectFunction=“ . . . ” runat=“ server”> <HeaderPromptTemplate/> <ContentPromptTemplate/> <GrammarTemplate/> <columns> <ColumnTemplate/> </columns> <grammars> <grammar type=“Next” src=“ . . . ” active=“true|false”/> grammar type=“Previous” src=“ . . . ” active=“true|false”/> <grammar type=“First” src=“ . . . ” active=“true|false”/> <grammar type=“Last” src=“ . . . ” active=“true|false”/> <grammar type=“Read” src=“ . . . ” active=“true|false”/> <grammar type=“Select” src=“ . . . ” active=“true|false”/> <grammar type=“Repeat” src=“ . . . ” active=“true|false”/> </grammars> </speech:DataTableNavigator> 4.4 Operation This control is a voice-only control. It does not output anything in multi-modal mode. 4.4.1 Execution Flow In voice only mode, the control execution follows the following flow: If automatic navigation is off: 1. Play DataHeaderFields (or prompts returned from PromptSelectFunction, or prompts specified by HeaderTemplate). 2. Ask for command. 3. If: a. User asks for full content or a specific column, play DataContentFields. Go to 2. b. User asks for navigation (previous/next/repeat) go to specified row. Go to 1. c. User utters exit command, stop d. User asks for header, go to 1. If automatic navigation is on, step 2 is replaced by a short timeout after step 1 and silence means “next”. At the bottom of the data rows, the Next On Last Error Message is played, auto navigation is disabled, then go to 2. If the DataSource property contains no data, the control does not render. 4.4.2 Default Prompts Question prompt: Question or if Question=“ ” then “Next command?” Question help: “Please say read, next, previous or cancel.” Silence: “I didn't hear you” NoReco: “I didn't understand you” Previous On First Error Message: “You are already on the first item.” Next On Last Error Message: “You are already on the last item.” Previous/Next On Only Item Error Message: “This is the only item available.” 5 AlphaDigit Control The AlphaDigit control retrieves a string of numbers and letters. The format of the string is determined by a mask. class AlphaDigit : ApplicationControl { string SemanticItem{get; Set}; bool Grouping{get; set;}; string InputMask{get; set;}; string PromptSelectFunction{get; set;}; } 5.1 AlphaDigit Properties Common properties are described above. SemanticItem Required. Used in both multimodal and voice-only modes. The ID of the semantic item receiving the value spoken by the user. The spokenText expando property of the SemanticItem will be set to the spoken text used by the user to input an alphadigit. An exception will be thrown if SemanticItem is not specified or if it is not a valid semantic item, e.g, the ID does not correspond to an element on the page or it corresponds to an element that is not a semantic item. Grouping Optional. Used in both multimodal and voice-only modes. Default: true. This flag decides whether digit groupings (e.g. Thirteen fifteen for 1315) are allowed. Grouping can only occur when the input masks specifies digits using wildcards. For example: [?] [?] allows “thirteen”, but [0-9] [0-9] does not. InputMask Required. Used in both multimodal and voice-only modes. The InputMask defines the format of the input to the AlphaDigit control. The format must follow the following rules. 1. Each position in valid input strings is characterized by a wildcard or a range in brackets. 2. A wildcard can be either “A” for an alphabetical character, “D” for a numerical character, or “.” for either a numerical or alphabetical character. Each wildcard represents one character only. 3. A range in brackets specifies what characters are acceptable. The allowable characters can be listed without spaces or commas. For example: [123] allows “one,” “two,” or “three.” A single character in brackets is also permitted, i.e., [1] is valid. A range of allowed characters or numbers can also be specified with a hyphen: [1-3] allows values one through three. A range specified in the form [x-y] is valid only if x<y. Mutiple range and/or values can be concatenated together in a set: [1-5a-eiou]. Overlapping ranges are allowed; [1-53-8] is valid. Wildcard characters are not permitted inside brackets; [A] is not valid. 4. Spaces are permitted anywhere in the input mask string and are ignored. 5. InputMask syntax is case sensitive. Ranges of letters must be specified in lowercase, [a-e], and wildcards must be specified in upper case. 6. White space only input masks, and any input masks not constructed according to the above rules will generate an error at design time. Empty input masks will generate an error at runtime. PromptSelectFunction The QA parameter passed to this function may be either: “question”, “confirm” or “acknowledge”. See Section 1.1.1 BasicApplicationControl Properties for a description of the PromptSelectFunction and its parameters. 5.2 Client-Side Object The client-side object is reserved for future use and is not documented at this time. 5.3 Mark-Up <speech:AlphaDigit id=”...” SpeechIndex=”...” AllowCommands=”...” BabbleTimeout=”...” BargeIn=”...” CarrierGrammarUrl=”...” ClientActivationFunction=”...” EndSilence=”...” InitialTimeout=”...” MaxTimeout=”...” OnClientActiveFirst=”...” OnClientCompleteLast=”...” PostAnswerCarrierRule=”...” PreAnswerCarrierRule=”...” PromptSelectFunction=”...” QuestionPrompt=”...” PromptDatabase=”...” AutoPostback=”...” ConfirmThreshold=”...” ConfirmRejectThreshold=”...” CompleteLast=”...” Mode=”...” OnClientActive=”...” OnClientComplete=”...” OnClientListening=”...” PostConfirmCarrierRule=”...” PreConfirmCarrierRule=”...” RejectThreshold=”...” StartElement=”...” StartEvent=”...” StopElement=”...” StopEvent=”...” SemanticItem=”...” Grouping=”...” InputMask=”...” runat=“server”/> 5.4 Operation 5.4.1 Execution Flow In voice only mode, the control execution follows the following flow: SpeechIndex QA 1 Confirm 2 Question 3 Done In multimodal mode, the start event starts the recognition for the whole alpha-digit string and binds the results. 5.4.2 Default Prompts The default prompts are: Question QA Question: Must be specified by user or an error will be returned. Help: “Please tell me a series of letters and or digits”+Question Confirm QA Confirm: “Did you say”+SemanticItem.spokenText ConfirmHelp: “Please say yes or no, or tell me the correct series of letters or digits.” Also, if short timeout confirmation is allowed, i.e., FirstInitialTimeout >0, the prompt is: SemanticItem.spokenText+? Done QA Prompt:“ ” All QA Controls Silence: “I didn't hear you.” NoReco: “I didn't understand you.” 5.5 Examples control: “What is the number?” User: “one four two five one” control: “Did you say 1 4 2 5 1?” User: “yes” 6 NaturalNumber Control The NaturalNumber control retrieves a natural number between 0 and 999,999. The NaturalNumber control also inherits from IDTMF interface. class NaturalNumber : ApplicationControl { string SemanticItem{get; set;}; int LowerBound{get; set;}; int UpperBound{get; set;}; SemanticEvent ValidationEvent{get; set;}; string PromptSelectFunction{get; set;}; } 6.1 Numeral Properties Common properties are describes above. SemanticItem Required. Used in both multimodal and voice-only modes. The ID of the semantic item receiving the value spoken by the user. An exception will be thrown if SemanticItem is not specified or if it is not a valid semantic item, e.g., the ID does not correspond to an element on the page or it corresponds to an element that is not a semantic item. LowerBound Optional. Used in both multimodal and voice-only modes. Default: 0. Lower boundary of acceptable answers. Must be greater than zero and less than UpperBound. An exception will be thrown if LowerBound is less than zero or greater or equal to UpperBound. UpperBound Optional. Used in both multimodal and voice-only modes. Default: 999,999. Upper boundary of acceptable answers. An exception will be thrown if UpperBound greater than 999,999 or is less than or equal to LowerBound. ValidationEvent Optional. Only used in voice-only mode. Default is SemanticEvent.onconfirmed. Must be either SemanticEvent.onconfirmed or SemanticEvent.onchanged. Indicates when the control will validate that the number is within the range specified, either after the number is input (or changed) or after the number has been confirmed. PromptSelectFunction Optional. Only used in voice-only mode. The QA parameter passed to this function may be either: “question”, “confirm”, “validation”, “acknowledge”. See Section 1.1.1 BasicApplicationControl Properties for a description of the PromptSelectFunction and its parameters. 6.2 Client-Side Object The object passed to this function contains the following properties: int LowerBound {get;} the lower bound; int UpperBound {get;} the upper bound; 6.3 Mark-Up <speech:NaturalNumber id=”...” SpeechIndex=”...” AllowCommands=”...” BabbleTimeout=”...” BargeIn=”...” CarrierGrammarUrl=”...” ClientActivationFunction=”...” EndSilence=”...” InitialTimeout=”...” MaxTimeout=”...” OnClientActiveFirst=”...” OnClientCompleteLast=”...” PostAnswerCarrierRule=”...” PreAnswerCarrierRule=”...” PromptSelectFunction=”...” QuestionPrompt=”...” PromptDatabase=”...” AutoPostback=”...” ConfirmThreshold=”...” ConfirmRejectThreshold=”...” CompleteLast=”...” Mode=”...” OnClientActive=”...” OnClientComplete=”...” OnClientListening=”...” PostConfirmCarrierRule=”...” PreConfirmCarrierRule=”...” RejectThreshold=”...” StartElement=”...” StartEvent=”...” StopElement=”...” StopEvent=”...” SemanticItem=”...” LowerBound=”...” UpperBound=”...” AllowDTMF=”...” InterDigitTimeout=”...” OnClientKeyPress=”...” PreFlush=”...” runat=“server”/> 6.4 Operation 6.4.1 Execution Flow In voice only mode, the control execution follows the following flow: SpeechIndex QA 1 Confirm 2 Question 3 Validate 4 Done In multimodal mode, the start event starts recognition for the number. If the number is in the lowerbound-upperbound range, the value is bound. 6.4.2 Default Prompts The default prompts are: Question QA Question: Must be specified by user or an error will be returned. Question help: Say a number. Confirm QA Confirm: “Did you say”+SemanticItem.value ConfirmHelp: “Confirm by saying yes or no, or tell me the correct number”. Also, if short timeout confirmation is allowed, i.e., FirstInitialTimeout >0, the prompt is: SemanticItem.value Validation QA Prompt: “I am expecting a number from lowerbound to upperbound” if LowerBound is >0 Prompt: “I am expecting a number larger than lowerbound and smaller than upperbound” The default lowerbound is zero and the default upper bound is 1,000,000. if number recognized is > UpperBound All QA controls Silence: “I didn't hear you.” NoReco: “I didn't understand you.” 6.5 Examples control: “How many do you want?” User: “twenty” control: “Did you say 20? User: “yes” 7 Currency Control The Currency control retrieves an amount in US Dollars. The Currency control also inherits from the IDTMF interface. class Currency : ApplicationControl { string SemanticItem{get; set;}; bool PreferDollars{get; set;}; string PromptSelectFunction{get; set;}; } 7.1 Properties Common properties are described above. SemanticItem Required. Used in both multimodal and voice-only modes. The ID of the semantic item receiving the value spoken by the user. An exception will be thrown if SemanticItem is not specified or if it is not a valid semantic item, e.g., the ID does not correspond to an element on the page or it corresponds to an element that is not a semantic item. PreferDollars Optional. Used in both multimodal and voice-only modes. Default: false. When users say an amount like “two fifty”, this can be interpreted as either $2.50 or $250. If PreferDollars is true, the amount that does not use cents is preferred. Otherwise the amount using cents is preferred. There is no upper limit on the amount of currency recognized using this control, it is the responsibility of the application developer to implement any desired limits. PromptSelectFunction Optional. Only used in voice-only mode. The QA parameter passed to this function may be either: “question”, “confirm” or “acknowledge”. See Section 1.1.1 BasicApplicationControl Properties for a description of the PromptSelectFunction and its parameters. 7.2 Client-Side Object The client-side object is reserved for future use and is not documented at this time. 7.3 Mark-Up <speech:Currency id=”...” SpeechIndex=”...” AllowCommands=”...” BabbleTimeout=”...” BargeIn=”...” CarrierGrammarUrl=”...” ClientActivationFunction=”...” EndSilence=”...” InitialTimeout=”...” MaxTimeout=”...” OnClientActiveFirst=”...” OnClientCompleteLast=”...” PostAnswerCarrierRule=”...” PreAnswerCarrierRule=”...” PromptSelectFunction=”...” QuestionPrompt=”...” PromptDatabase=”...” AutoPostback=”...” ConfirmThreshold=”...” ConfirmRejectThreshold=”...” CompleteLast=”...” Mode=”...” OnClientActive=”...” OnClientComplete=”...” OnClientListening=”...” PostConfirmCarrierRule=”...” PreConfirmCarrierRule=”...” RejectThreshold=”...” StartElement=”...” StartEvent=”...” StopElement=”...” StopEvent=”...” AllowDTMF=”...” InterDigitTimeout=”...” OnClientKeyPress=”...” PreFlush=”...” SemanticItem=”...” PreferDollars=”...” runat=“server”/> 7.4 Operation The control understands amounts up to 1 million. Amounts like “two ninety nine” are resolved based on the value of the PreferDollars property. 7.4.1 Execution Flow In voice only mode, the control execution follows the following flow: SpeechIndex QA 1 Confirm 2 Question 3 Done In multimodal mode, the start event starts recognition for the whole amount and binds the results. 7.4.2 Default Prompts The default prompts are: Question QA Question: Must be specified by user or an error will be returned. Question Help: “Please tell me an amount. For example ten dollars or ten dollars and fifty cents.”+Question Confirm QA Confirm: “Did you say”+SemanticItem.value ConfirmHelp: “Please say yes or no, or tell me the correct amount.” If short timeout confirmation is allowed, i.e., FirstInitialTimeout >0, the prompt is: SemanticItem.value+? Done QA Prompt: “ ” All QA controls Silence: “I didn't hear you” NoReco: “I didn't understand you” 8 Phone Control The Phone control retrieves a 10 digit US Phone number. If the user includes an extra digit at the beginning of the phone number (such as a 1 for long distance or a 9 for dial out) the extra digit will be dropped. The Phone control also inherits from the IDTMF interface. class Phone : ApplicationControl { string AreaCodeSemanticItem{get; set;}; string LocalNumberSemanticItem{get; set;}; string ExtensionSemanticItem{get; set;}; string StartElementAreaCode{get; set;}; string StartEventAreaCode{get; set;}; string StopElementAreaCode{get; set;}; string StopEventAreaCode{get; set;}; string StartElementLocalNumber{get; set;}; string StartEventLocalNumber{get; set;}; string StopElementLocalNumber{get; set;}; string StopEventLocalNumber{get; set;}; string StartElementExtension{get; set;}; string StartEventExtension{get; set;}; string StopElementExtension{get; set;}; string StopEventExtension{get; set;}; string PromptSelectFunction{get; set;}; bool RequiresAreaCode{get; set;}; } 8.1 Phone Properties Common properties are described above. AreaCodeSemanticItem Required. Used in both multimodal and voice-only modes. The ID of the semantic item receiving the area code value spoken by the user. If the retrieved area code starts with a “1” e.g., “1-800”, the “1” is not returned in the results. An exception will be thrown if AreaCodeSemanticItem is not specified or if it is not a valid semantic item, e.g., the ID does not correspond to an element on the page or it corresponds to an element that is not a semantic item. LocalNumberSemanticItem Required. Used in both multimodal and voice-only modes. The ID of the semantic item receiving the local number value spoken by the user. An exception will be thrown if LocalNumberSemanticItem is not specified or if it is not a valid semantic item, e.g., the ID does not correspond to an element on the page or it corresponds to an element that is not a semantic item. ExtensionSemanticItem Optional. Used in both multimodal and voice-only modes. The ID of the semantic item receiving the extension value spoken by the user. If specified the control will allow the user to enter an extension. The maximum length of the extension is five digits. If specified, an exception will be thrown if ExtensionSemanticItem is not a valid semantic item, e.g., the ID does not correspond to an element on the page or it corresponds to an element that is not a semantic item. StartElementAreaCode Optional. Only used in multimodal mode. Default=“ ”. The id of the GUI control whose event starts recognition of the area code part. StopElementAreaCode Optional. Only used in multimodal mode. Default=“ ”. The id of the GUI control whose event stops recognition of the area code part. StartEventAreaCode Optional. Only used in multimodal mode. Default=“ ”. The name of the event that starts recognition of the area code part. StopEventAreaCode Optional. Only used in multimodal mode. Default=“ ”. The name of the event that stops recognition of the area code part. StartElementLocalNumber Optional. Only used in multimodal mode. Default=“ ”. The id of the GUI control whose event starts recognition of the local number part. StopElementLocalNumber Optional. Only used in multimodal mode. Default=“ ”. The id of the GUI control whose event stops recognition of the local number part. StartEventLocalNumber Optional. Only used in multimodal mode. Default=“ ”. The name of the event that starts recognition of the local number part. StopEventLocalNumber Optional. Only used in multimodal mode. Default=“ ”. The name of the event that stops recognition of the local number part. StartElementExtension Optional. Only used in multimodal mode. Default=“ ”. The id of the GUI control whose event starts recognition of the extension part. StopElementExtension Optional. Only used in multimodal mode. Default=“ ”. The id of the GUI control whose event stops recognition of the extension part. StartEventExtension Optional. Only used in multimodal mode. Default=“ ”. The name of the event that starts recognition of the extension part. StopEventExtension Optional. Only used in multimodal mode. Default=“ ”. The name of the event that stops recognition of the extension part. PromptSelectFunction Optional. Only used in voice-only mode. The QA parameter passed to this function may be either: “question”, “confirmLocalNumber”, “questionAreaCode”, “confirmAreaCode”, “questionExtension”, “confirmExtension”, or “acknowledge”. See Section 1.1.1 BasicApplicationControl Properties for a description of the PromptSelectFunction and its parameters. RequiresAreaCode Optional. Used in both multimodal and voice-only modes. If true, the control will ask for area code. If false, the control will not ask for area code. 8.2 Client-Side Object The client-side object is reserved for future use and is not documented at this time. 8.3 Mark-Up <speech:Phone id=”...” SpeechIndex=”...” AllowCommands=”...” BabbleTimeout=”...” BargeIn=”...” CarrierGrammarUrl=”...” ClientActivationFunction=”...” EndSilence=”...” InitialTimeout=”...” MaxTimeout=”...” OnClientActiveFirst=”...” OnClientCompleteLast=”...” PostAnswerCarrierRule=”...” PreAnswerCarrierRule=”...” PromptSelectFunction=”...” QuestionPrompt=”...” PromptDatabase=”...” AutoPostback=”...” ConfirmThreshold=”...” ConfirmRejectThreshold=”...” CompleteLast=”...” Mode=”...” OnClientActive=”...” OnClientComplete=”...” OnClientListening=”...” PostConfirmCarrierRule=”...” PreConfirmCarrierRule=”...” RejectThreshold=”...” StartElement=”...” StartEvent=”...” StopElement=”...” StopEvent=”...” AllowDTMF=”...” InterDigitTimeout=”...” OnClientKeyPress=”...” PreFlush=”...” StartElementAreaCode=”...” StopElementAreaCode=”...” StartEventAreaCode=”...” StopEventAreaCode=”...” StartElementLocalNumber=”...” StopElementLocalNumber=”...” StartEventLocalNumber=”...” StopEventLocalNumber=”...” StartElementExtension=”...” StopElementExtension=”...” StartEventExtension=”...” StopEventExtension=”...” AreaCodeSemanticItem=”...” LocalNumberSemanticItem=”...” ExtensionSemanticItem=”...” RequiresAreaCode=”...” runat=“server”/> 8.4 Operation 8.4.1 Execution Flow The collection of digits is split into: 3-7-X where X is the number of extension digits, up to 5. In voice only mode, the control execution follows the following flow: SpeechIndex QA 1 QuestionLocalNumber 2 QuestionAreaCode 3 ConfirmLocalNumber 4 ConfirmAreaCode 5 QuestionExtension 6 ConfirmExtension 7 Done In multimodal mode, the start event starts the recognition for the whole phone number and binds the result. Area code, local number and extension start events start recognition for those semantic items separately. 8.4.2 Default Prompts The default prompts are: QuestionFullNumber: Question: Must be specified by user or an error will be returned. Help: “Please tell me the phone number.” QuestionLocalNumber QA Question: QuestionPrompt Help: “Please tell me the seven digit local phone number” QuestionAreaCode QA AreaCodeQuestion: “What is the Area Code?” Help: “Please tell me the three digit area code” QuestionExtension QA ExtensionQuestion: “Any extension?” Help: “Please tell me the extension number. Say no extension if there is none.” ConfirmAreaCode QA “Is the area code”+AreaCodeSemanticItem.value+? If short timeout confirmation is enabled, i.e., FirstInitialTimeout>0, then the prompt is: AreaCodeSemanticItem.value+? ConfirmLocalNumber QA “Is the number”+LocalNumberSemanticItem.value+? If short timeout confirmation is enabled, i.e., FirstInitialTimeout>0, then the prompt is: LocalNumberSemanticItem.value+? ConfirmExtension QA If an extension is detected, the prompt is: “Is the extension”+ExtensionSemanticItem.value+? If short timeout confirmation is enabled, i.e., FirstInitialTimeout>0, then the prompt is: ExtensionSemanticItem.value+? If the user says “No” to the QuestionExtension prompt, the confirm prompt is: No extension, is that right? All Confirm QA Controls Help: “Please say yes or no, or tell me the correct number.”. All QA Controls Silence: “I didn't hear you.” NoReco: “I didn't understand you.” 9 ZipCode Control The ZipCode control retrieves a US Zip Code. The Zip Code control also inherits from the IDTMF interface. class ZipCode : ApplicationControl { string ZipCodeSemanticItem{get; set;}; string ExtensionSemanticItem{get; set;}; string StartElementZipcode{get; set;}; string StartEventZipCode{get; set;}; string StopElementZipCode{get; set;}; string StopEventZipCode{get; set;}; string StartElementExtension{get; set;}; string StartEventExtension{get; set;}; string StopElementExtension{get; set;}; string StopEventExtension{get; set;}; string PromptSelectFunction{get; set;}; } 9.1 ZipCode Properties Common properties are described above. ZipcodeSemanticItem Required. Used in both multimodal and voice-only modes. The ID of the semantic item receiving the zipcode value spoken by the user. The “value” expando property of the ZipcodeSemanticItem will be set to the text spoken by the user when entering a zip code. An exception will be thrown if ZipcodeSemanticItem is not specified or if it is not a valid semantic item, e.g., the ID does not correspond to an element on the page or it corresponds to an element that is not a semantic item. ExtensionSemanticItem Optional. Used in both multimodal and voice-only modes. The ID of the semantic item receiving the extension value spoken by the user. If the extension semantic item id is not specified the control will not ask for an extension and no QA controls related to the extension will be output. If specified, an exception will be thrown if the ID does not correspond to an element on the page or it corresponds to an element that is not a semantic item. StartElementZipcode Optional. Only used in multimodal mode. Default=“ ”. The id of the GUI control whose event starts recognition of the zipcode. StopElementZipcode Optional. Only used in multimodal mode. Default=“ ”. The id of the GUI control whose event stops recognition of the zipcode. StartEventZipcode Optional. Only used in multimodal mode. Default=“ ”. The name of the event that starts recognition of the zipcode. StopEventZipcode Optional. Only used in multimodal mode. Default=“ ”. The name of the event that stops recognition of the zipcode. StartElementExtension Optional. Only used in multimodal mode. Default=“ ”. The id of the GUI control whose event starts recognition of the extension. StopElementExtension Optional. Only used in multimodal mode. Default=“ ”. The id of the GUI control whose event stops recognition of the extension. StartEventExtension Optional. Only used multimodal mode. Default=“ 38 . The name of the event that starts recognition of the extension part. StopEventExtension Optional. Only used in multimodal mode. Default=“ ”. The name of the event that stops recognition of the extension part. PromptSelectFunction Optional. Only used in voice-only mode. The QA parameter passed to this function may be either: “question”, “questionExtension”, “confirmCode”, “confirmExtension”, “acknowledge”. See Section 1.1.1 BasicApplicationControl Properties for a description of the PromptSelectFunction and its parameters. 9.2 Client-Side Object The client-side object is reserved for future use and is not documented at this time. 9.3 Mark-Up <speech:ZipCode id=”...” SpeechIndex=”...” AllowCommands=”...” BabbleTimeout=”...” BargeIn=”...” CarrierGrammarUrl=”...” ClientActivationFunction=”...” EndSilence=”...” InitialTimeout=”...” MaxTimeout=”...” OnClientActiveFirst=”...” OnClientCompleteLast=”...” PostAnswerCarrierRule=”...” PreAnswerCarrierRule=”...” PromptSelectFunction=”...” QuestionPrompt=”...” PromptDatabase=”...” AutoPostback=”...” ConfirmThreshold=”...” ConfirmRejectThreshold=”...” CompleteLast=”...” Mode=”...” OnClientActive=”...” OnClientComplete=”...” OnClientListening=”...” PostConfirmCarrierRule=”...” PreConfirmCarrierRule=”...” RejectThreshold=”...” StartElement=”...” StartEvent=”...” StopElement=”...” StopEvent=”...” AllowDTMF=”...” InterDigitTimeout=”...” OnClientKeyPress=”...” PreFlush=”...” StartElementZipcode=”...” StopElementZipcode=”...” StartEventZipcode=”...” StopEventZipcode=”...” StartElementExtension=”...” StopElementExtension=”...” StartEventExtension=”...” StopEventExtension=”...” ZipCodeSemanticItem=”...” ExtensionSemanticItem=”...” runat=“server”/> 9.4 Operation The control asks the question/confirmation repeatedly until an answer is obtained with confidence above the ConfirmThreshold or it is confirmed. The collection of digits is split into: 5-4. 9.4.1 Execution Flow In voice only mode, the control execution follows the following flow: SpeechIndex QA 1 ConfirmZipCode 2 ConfirmExtension 3 QuestionZipCode 4 QuestionExtension 5 Done In multimodal mode, the start event starts the recognition for the whole zip code and binds the result. Events hooked to individual items start collection only for the associated item. 9.4.2 Default Prompts The default prompts are: QuestionZipCode QA Question: Must be specified by user or an error will be returned. Help: “Please tell me the zip code.” QuestionExtension QA ExtensionQuestion: “Any zip plus four extension?” Help: “Please tell me the zip plus four extension, say no extension if there is none” ConfirmZipCode QA Question: “Did you say”+ZipcodeSemanticItem.value+? Confirmation Help: “Please say yes or no or tell me the correct number.” If short timeout confirmation is enabled, i.e., FirstInitialTimeout>0, then the prompt is: ZipcodeSemanticItem.value+? ConfirmExtension QA Question: “Did you say”+ExtensionSemanticItem.value+? Confirmation: “There is no extension. Is that right?” If short timeout confirmation is enabled, i.e., FirstInitialTimeout>0, then the prompt is: ExtensionSemanticItem.value+? All QA controls Silence: “I didn't hear you” NoReco: “I didn't understand you” 10 SocialSecurityNumber Control The SocialSecurityNumber control retrieves a US Social Security number. The SocialSecurityNumber control also inherits from the IDTMF interface. class SocialSecurityNumber : ApplicationControl { string SemanticItem{get; set;}; string Separator{get; set;}; string PromptSelectFunction{get; set;}; } 10.1 SocialSecurityNumber Properties Common properties are described above. SemanticItem Required. Used in both multimodal and voice-only modes. The ID of the semantic item receiving the value spoken by the user. The “value” expando property of SemanticItem will be set to the text spoken by the user when entering a social security number. An exception will be thrown if SemanticItem is not specified or if it is not a valid semantic item, e.g., the ID does not correspond to an element on the page or it corresponds to an element that is not a semantic item. Separator Optional. Used in both multimodal and voice-only modes. This string (like “-”) will be inserted between the fields. The Separator is not used in the grammar, e.g., “123 dash 45 dash 6789” returns a noreco. PromptSelectFunction Optional. Only used in voice-only mode. The QA parameter passed to this function may be either: “question”, “questionFiled2”, “questionFiled3”, “confirmFiled1”, “confirmField2”, “confirm Field3”, “acknowledge”. For confirms, the SemanticItemList parameter will contain one semantic item object holding the value to confirm. See Section 1.1.1 BasicApplicationControl Properties for a description of the PromptSelectFunction and its parameters. 10.2 Client-Side Object The client-side object is reserved for future use and is not documented at this time. 10.3 Mark-Up <speech:SocialSecurityNumber id=”...” SpeechIndex=”...” AllowCommands=”...” BabbleTimeout=”...” BargeIn=”...” CarrierGrammarUrl=”...” ClientActivationFunction=”...” EndSilence=”...” InitialTimeout=”...” MaxTimeout=”...” OnClientActiveFirst=”...” OnClientCompleteLast=”...” PostAnswerCarrierRule=”...” PreAnswerCarrierRule=”...” PromptSelectFunction=”...” QuestionPrompt=”...” PromptDatabase=”...” AutoPostback=”...” ConfirmThreshold=”...” ConfirmRejectThreshold=”...” CompleteLast=”...” Mode=”...” OnClientActive=”...” OnClientComplete=”...” OnClientListening=”...” PostConfirmCarrierRule=”...” PreConfirmCarrierRule=”...” RejectThreshold=”...” StartElement=”...” StartEvent=”...” StopElement=”...” StopEvent=”...” AllowDTMF=”...” InterDigitTimeout=”...” OnClientKeyPress=”...” PreFlush=”...” SemanticItem=”...” Separator=”...” runat=“server”/> 10.4 Operation The collection of digits is split into: 3-2-4. There are 3 hidden semantic item objects created to hold values for the 3 parts of a social security number. The appropriate hidden semantic item object is passed to the PromptSelectFunction during confirmation of the corresponding part of the social security number. The semantic item object specified by the SemanticItem property of the control is filled using the hidden objects just before the OnClientCompleteLast function call. 10.4.1 Execution Flow In voice only mode, the control execution follows the following flow: SpeechIndex QA 1 Field1Confirm 2 Field2Confirm 3 Field3Confirm 4 ConfirmFullNumber 5 MainQuestion 6 Field2Question 7 Field3Question 8 Done For a social security number gathered outside and passed into the SocialSecurityNumber control for confirmation, the voice-only execution begins at SpeechIndex 4. In multimodal mode, the start event starts the recognition for the whole social security number and binds the result. 10.4.2 Default Prompts The default prompts are: MainQuestion QA Question: Must be specified by user or an error will be returned. Help: “Please tell me the social security number.” Field Question QA Controls Field2 Question: “What are the next two digits?” Field3 Question: “What are the last four digits?” Help: “Please tell me the remaining digits of the social security number.” Field Confirm QA Controls “Is the social security number”+SemanticItem.value+? If short timeout confirmation is enabled (FirstInitialTimeout>0), the prompt is: SemanticItem.value+? Help=“Please say yes or no, or tell me the correct digits.” Done QA Prompt: “ ” All QA Controls Silence: “I didn't hear you.” NoReco: “I didn't understand you.” For a social security number gathered outside the SocialSecurityNumber control, the confirmation prompt is: Is your social security number+SemanticItem.value+? 10.4.3 Examples control: “What is your social security number?” User: “one two three four five six seven eight nine” control: “1 2 3” User: “yes” (or short time out confirmation) control: “4 5” User: “yes” (or short time out confirmation) control: “6 7 8 9” User: “ ” (short time out confirmation) (for a social security number gathered outside the SocialSecurityNumber control) control: “Is your social security number 1 2 3 4 5 6 7 8 9?” User: “No, it's 9 8 7 6 5 4 3 2 1” 11 Date Control The Date control retrieves a date. class Date : ApplicationControl { string DaySemanticItem{get; set;}; string MonthSemanticItem{get; set;}: string YearSemanticItem{get; set;}; Enumeration DateContextEnumeration; DateContextEnumeration DateContext{get; set;}; bool AllowRelativeDates{get; set;}; bool AllowHolidays{get; set;}; bool AllowNumeralDates{get; set;}; string PromptSelectFunction{get; set;}; string StartElementDay{get; set;}; string StartEventDay{get; set;}; string StartElementMonth{get; set;}; string StartEventMonth{get; set;}; string StartElementYear{get; set;}; string StartEventYear{get; set;}; string StopElementDay{get; set;}; string StopEventDay{get; set;}; string StopElementMonth{get; set;}; string StopEventMonth{get; set;}; string StopElementYear{get; set;}; string StopEventYear{get; set;}; int FallbackCount{get; set;}; } 11.1 Date Properties Common properties are described above. DaySemanticItem Required. Used in both multimodal and voice-only modes. The ID of the semantic item receiving the day value spoken by the user. If the value is assumed by the control and the semantic item is empty, the “assumed” expando property of DaySemanticItem will be set to true. This property is removed when the value is confirmed by the user. The “spokenText” expando property will be set to the text spoken by the user which effectively enters the day (e.g., “tomorrow”). An exception will be thrown if DaySemanticItem is not specified or if it is not a valid semantic item, e.g., the ID does not correspond to an element on the page or it corresponds to an element that is not a semantic item. MonthSemanticItem Required. Used in both multimodal and voice-only modes. The ID of the semantic item receiving the month value spoken by the user. If the value is assumed by the control and the semantic item is empty, the “assumed” expando property of MonthSemanticItem will be set to true. This property is removed when the value is confirmed by the user. The “spokenText” expando property will be set to the text spoken by the user which effectively enters the month (e.g., “tomorrow”). An exception will be thrown if MonthSemanticItem is not specified or if it is not a valid semantic item, e.g., the ID does not correspond to an element on the page or it corresponds to an element that is not a semantic item. YearSemanticItem Optional. Used in both multimodal and voice-only modes. The ID of the semantic item receiving the year value spoken by the user. If the value is assumed by the control and the semantic item is empty, the “assumed” expando property of YearSemanticItem will be set to true. This property is removed when the value is confirmed by the user. The “spokenText” expando property will be set to the text spoken by the user which effectively enters the year (e.g., “tomorrow”). If specified, an exception will be thrown if YearSemanticItem is not a valid semantic item, e.g., the ID does not correspond to an element on the page or it corresponds to an element that is not a semantic item. If YearSemanticItem is not specified, the control will not ask for the year and no QA controls related to the year will be output. DateContext Optional. Used in both multimodal and voice-only modes. Default: Neutral. By specifying a DateContext, authors can help the control disambiguate users' answers. For example, ‘Christmas’ will either refer to last or next Christmas depending on the value specified in this property. The DateContext property is a DateContextEnumeration datatype and may be set to one of the following values: “Past”, “Future”, or “Neutral”. Neutral means no preference. AllowRelativeDates Optional. Used in both multimodal and voice-only modes. Default: false. If AllowRelativeDates is set to true, relative dates like “today”, “next Tuesday” are allowed. AllowHolidays Optional. Used in both multimodal and voice-only modes. Default: false. If AllowHolidays is set to true, holiday names such as Christmas are recognized. AllowNumeralDates Optional. Used in both multimodal and voice-only modes. Default: false. If AllowNumeralDates is set to true, we accept the numeral format like “eleven five sixty two” as Nov. 5, 1962. PromptSelectFunction Optioal. Only used in voice-only mode. The QA parameter passed to this function may be either: “questionDate”, “confirmDate”, “questionDay”, “confirmDay”, “questionMonth”, “confirmMonth”, “questionYear”, “confirmYear”, “validate”. StartElementDay Optional. Only used in multimodal mode. Default:“ ”. The id of the GUI control whose event starts recognition of the day. StartEventDay Optional. Only used in multimodal mode. Default:“ ”. Name of the event to start recognition for the day. StartElementMonth Optional. Only used in multimodal mode. Default:“ ”. The id of the GUI control whose event starts recognition of the month. StartEventMonth Optional. Only used in multimodal mode. Default:“ ”. Name of the event to start recognition for the month. StartElementDay Optional. Only used in multimodal mode. Default:“ ”. The id of the GUI control whose event starts recognition of the year. StartEventYear Optional. Only used in multimodal mode. Default:“ ”. Name of the event to start recognition for the year. StopElementDay Optional. Only used in multimodal mode. Default:“ ”. The id of the GUI control whose event stops recognition of the day. StopEventDay Optional. Only used in multimodal mode. Default:“ ”. Name of the event to stop recognition for the day. StopElementMonth Optional. Only used in multimodal mode. Default:“ ”. The id of the GUI control whose event stops recognition of the month. StopEventMonth Optional. Only used in multimodal mode. Default:“ ”. Name of the event to stop recognition for the month. StopElementYear Optional. Only used in multimodal mode. Default:“ ”. The id of the GUI control whose event stops recognition of the year. StopEventYear Optional. Only used in multimodal mode. Default:“ ”. Name of the event to stop recognition for the year. FallbackCount Optional. Only used in voice-only mode. Default: 3. Must be greater than or equal to 0. Number of misrecognitions or silences when gathering a full date before the control switches to gathering individual date items. If FallbackCount=0, the control switches immediately. An exception will be thrown for negative values of FallbackCount. 11.2 Client-Side Object The client-side object is reserved for future use and is not documented at this time. 11.3 Mark-Up <speech:Date id=”...” SpeechIndex=”...” AllowCommands=”...” BabbleTimeout=”...” BargeIn=”...” CarrierGrammarUrl=”...” ClientActivationFunction=”...” EndSilence=”...” InitialTimeout=”...” MaxTimeout=”...” OnClientActiveFirst=”...” OnClientCompleteLast=”...” PostAnswerCarrierRule=”...” PreAnswerCarrierRule=”...” PromptSelectFunction=”...” QuestionPrompt=”...” PromptDatabase=”...” AutoPostback=”...” ConfirmThreshold=”...” ConfirmRejectThreshold=”...” CompleteLast=”...” Mode=”...” OnClientActive=”...” OnClientComplete=”...” OnClientListening=”...” PostConfirmCarrierRule=”...” PreConfirmCarrierRule=”...” RejectThreshold=”...” StartElement=”...” StartEvent=”...” StopElement=”...” StopEvent=”...” StartElementDay=”...” StopElementDay=”...” StartEventDay=”...” StopEventDay=”...” StartElementMonth=”...” StopElementMonth=”...” StartEventMonth=”...” StopEventMonth=”...” StartElementYear=”...” StopElementYear=”...” StartEventYear=”...” StopEventYear=”...” DaySemanticItem=”...” MonthSemanticItem=”...” YearSemanticItem=”...” AllowRelativeDates=”...” AllowHolidays=”...” AllowNumeralDates=”...” FallBackCount=”...” runat=”server”/> 11.4 Operations 11.4.1 Execution Flow In voice only mode, the control execution follows the following flow: SpeechIndex QA 1 DateConfirm 2 DateQuestion 3 MonthConfirm 4 MonthQuestion 5 DayConfirm 6 DayQuestion 7 YearConfirm 8 YearQuestion 9 Validation 10 Done The control will turn off the mainQA and mainConfirmQA and fall back to individual QA controls to collect and confirm the day, month and year information separately when the number of corrections or the count of norecos of either of the two QA controls exceeds FallbackCount. Relative dates are always confirmed so that the user can be sure that they have been properly resolved. In multimodal mode, the start event starts recognition for the whole date and binds the result. Individual start events can be specified to start recognition for a specific part of the date (day, month and year). Invalid dates such as Feb. 29, 2001 or Apr. 31 will be rejected as noreco. When an invalid date has been collected item by item, an invalid prompt will be played and all semantic items will be reset (value property will be set to “ ” and status property will be set to “EMPTY”). 11.4.2 Default Prompts The default prompts are: DateQuestion QA Question: Must be specified by user or an error will be returned. QuestionHelp: “Please tell me a date such as May eleventh this year”+Question DateConfirm QA “Did you say”+normalized(DaySemanticItem.value, MonthSemanticItem.value, YearSemanticItem.value) For example: User says “tomorrow” Confirm prompt: “Did you say 5 of Apr. 2002?” ConfirmHelp: “Please say yes or no, or tell me the correct date.” MonthQuestion QA Question: “Tell me the month.”; MonthHelp: “Please tell me the month. For example May.” MonthConfirm QA “Did you say”+normalized(MonthSemanticItem.value)+? For example: User says “5” Confirm prompt: “Did you say May? DayQuestion QA DayQuestion: “Tell me the day of the month.” DayHelp: “Please tell me the day of the month, for example, the eleventh.” DayConfirm QA “Did you say”+normailized(DaySemanticItem.value)+? For example: User says “tomorrow” Confirm prompt: “Did you say the 5th? YearQuestion QA YearQuestion: “Tell me the year”; Year Help: “Please tell me the year”; YearConfirm QA “Did you say”+normailized(YearSemanticItem.value) For example: User says “2003” Confirm prompt: “Did you say two thousand three? Validation Prompt normalized(DaySemanticItem.value, MonthSemanticItem.value, YearSemanticItem.value)+“is not a valid date” All QA controls Silence: “Sorry. I didn't hear you.” NoReco: “Sorry. I didn't understand you.” 11.4.3 Examples control: “Tell me the date.” User: “July first this year” control: “Did you say July the first this year?” User: “yes” control: “Tell me the date.” User: “July first” control: “Did you say July the first this year?” User: “yes” control: “Tell me the date.” User: “the first” control: “February the first this year?” User: “yes” 12 YesNo Control The YesNo control retrieves a Yes or No answer. The YesNo control also inherits from the IDTMF interface. class YesNo : ApplicationControl { string SemanticItem{get; set;}; } 12.1 YesNo Properties Common properties are described above. SemanticItem Required. Used in both multimodal and voice-only modes. The ID of the semantic item receiving the value. An exception will be thrown if SemanticItem is not specified or if it is not a valid semantic item, e.g., the ID does not correspond to an element on the page or it corresponds to an element that is not a semantic item. 12.2 Client-Side Object The client-side object is reserved for future use and is not documented at this time. 12.3 Mark-Up <speech:YesNo id=”...” SpeechIndex=”...” AllowCommands=”...” BabbleTimeout=”...” BargeIn=”...” CarrierGrammarUrl=”...” ClientActivationFunction=”...” EndSilence=”...” InitialTimeout=”...” MaxTimeout=”...” OnClientActiveFirst=”...” OnClientCompleteLast=”...” PostAnswerCarrierRule=”...” PreAnswerCarrierRule=”...” PromptSelectFunction=”...” QuestionPrompt=”...” PromptDatabase=”...” AutoPostback=”...” ConfirmThreshold=”...” ConfirmRejectThreshold=”...” CompleteLast=”...” Mode=”...” OnClientActive=”...” OnClientComplete=”...” OnClientListening=”...” PostConfirmCarrierRule=”...” PreConfirmCarrierRule=”...” RejectThreshold=”...” StartElement=”...” StartEvent=”...” StopElement=”...” StopEvent=”...” AllowDTMF=”...” InterDigitTimeout=”...” OnClientKeyPress=”...” PreFlush=”...” SemanticItem=”...” runat=”server”/> 12.4 Operation Allows speech-enabled page authors to get a yes-no answer from users. The answer can be used to fill in a text box or take author-specified action on yes or no. The control asks the question/confirmation repeatedly until an answer is obtained with confidence above the AcceptThreshold. If DTMF input is enabled, “1” means yes and “2” means no. 12.4.1 Execution Flow In voice only mode, the control execution follows the following flow: SpeechIndex QA 1 Confirm 2 Question 3 Done 12.4.2 Default Prompts The default prompts are: Question QA Question: Must be specified by user or an error will be returned. Question Help: “Please tell me yes or no.” Confirm QA Confirmation: “Did you say:” Confirmation help: “Say yes or no.” (the confirmation prompt is not replayed after the help prompt) Done QA Prompt:“ ” All QA Controls Silence: “I didn't hear you” NoReco: “I didn't understand you” 13 Exceptions The following table lists the exceptions thrown by the controls at render time. Control/Object Attribute/Method Condition Exception BasicApplication EndSilence EndSilence, ) ArgumentOutOfRangeException Control class BabbleTimeout BabbleTimeout < 0 ArgumentOutOfRangeException PreAnswerCarrier PreAnswerCarrierRule InvalidOperationException Rule is specified and CarrierGrammarUrl is not specified. PostAnswerCarrier PostAnswerCarrierRule InvalidOperationException Rule is specified and CarrierGrammarUrl is not specified. PreConfirmCarrier PreConfirmCarrierRule InvalidOperationException Rule is specified and CarrierGrammarUrl is not specified. PostConfirmCarrier PostConfirmCarrierRule InvalidOperationException Rule is specified and CarrierGrammarUrl is not specified. InitialTimeout InitialTimeout < 0 ArgumentOutOfRangeException MaxTimeout MaxTimeout < 0 ArgumentOutOfRangeException ApplicationControl AutoPostback AutoPostback is InvalidOperationException class true and CompleteLast not specified ConfirmThreshold ConfirmThreshold <0 ArgumentOutOfRangeException or >1 ConfirmReject ConfirmRejectThreshold ArgumentOutOfRangeException Threshold <0 or >1 FirstInitialTimeout FirstInitialTimeout < ArgumentoutOfRangeException 0 RejectThreshold RejectThreshold <0 ArgumentOutOfRangeException or >1 StartEvent StartEvent is InvalidOperationException specified and StartElement is not. StopEvent StopEvent is InvalidOperationException specified and StopElement is not. SingleItemChooser DataSource DataSource not ArgumentNullException specified DataTextField Missing from ArgumentException database DataBindField Missing from ArgumentException database DataTextField Duplicates in ArgumentException Control/Object Attribute/Method Condition Exception database SemanticItem SemanticItem not ArgumentNullException specified SemanticItem SemanticItem is not ArgumentException a valid semantic item Navigator InitialShortTimeout InitialShortTimeout < ArgumentOutOfRangeException 0 DataContentFields DataContentFields ArgumentNullException not specified DataHeaderFields DataHeaderFields ArgumentNullException not specified DataSource DataSource not ArgumentNullException specified AlphaDigit SemanticItem SemanticItem not ArgumentNullException specified SemanticItem SemanticItem is not ArgumentException a valid semantic item InputMask InputMask not ArgumentNullException specified InputMask InputMask is not a ArgumentException valid format NaturalNumber LowerBound LowerBound < 0 or ArgumentOutOfRangeException LowerBound > Upperbound UpperBound UpperBound > 999,999 ArgumentOutOfRangeException Currency SemanticItem SemanticItem not ArgumentNullException specified SemanticItem SemanticItem is not ArgumentException a valid semantic item Phone AreaCodeSemantic AreaCodeSemanticItem ArgumentNullException Item not specified AreaCodeSemantic AreaCodeSemanticItem ArgumentException Item is not a valid semantic item LocalNumberSemantic LocalNumberSemantic ArgumentNullException Item Item not specified LocalNumberSemantic LocalNumberSemantic ArgumentException Item Item is not a valid semantic item ExtensionSemantic ExtensionSemanticItem ArgumentException Item is specified and is not a valid semantic item Zipcode ZipcodeSemantic ZipcodeSemanticItem ArgumentNullException Item not specified ZipcodeSemantic ZipcodeSemanticItem ArgumentException Item is not a valid semantic item ExtensionSemantic ExtensionSemanticItem ArgumentException Item is specified and is not a valid semantic item SocialSecurity SemanticItem SemanticItem not ArgumentNullException Number specified SemanticItem SemanticItem is not ArgumentException a valid semantic item Date DaySemanticItem DaySemanticItem not ArgumentNullException specified DaySemanticItem DaySemanticItem is ArgumentException not a valid semantic item MonthSemantic MonthSemanticItem ArgumentNullException Item not specified MonthSemantic MonthSemanticItem ArgumentException Item is not a valid semantic item YearSemanticItem YearSemanticItem is ArgumentException specified and is not a valid semantic item FallbackCount FallbackCount < 0 ArgumentOutOfRangeException YesNo SemanticItem SemanticItem not ArgumentNullException specified SemanticItem SemanticItem is not ArgumentException a valid semantic item CreditCard CreditCardsAllowed CreditCardsAllowed ArgumentException is null NumberSemantic NumberSemanticItem ArgumentNullException Item not specified NumberSemantic NumberSemanticItem ArgumentException Item is not a valid semantic item ExpirationMonth ExpirationMonthSemantic ArgumentNullException SemanticItem Item not specified ExpirationMonth ExpirationMonthSemantic ArgumentException SemanticItem Item is not a valid semantic item ExpirationYear ExpirationYearSemantic ArgumentNullException SemanticItem Item not specified ExpirationYear ExpirationYearSemantic ArgumentException SemanticItem Item is not a valid semantic item AllowVisa/Allow No credit card InvalidOperationException Amex/AllowDiscover/ types are allowed, Allow i.e., at least one masterCard/Allow of the properties DinersClub is not true 14 DET Descriptions The following table lists brief descriptions for each control, object and property. These descriptions will be used by the DET tool and be exposed to the dialog author using Visual Studio. Control/object Attribute/Method/Object Brief description BasicApplication AllowCommands Whether or not commands may Control class be activated in the control BabbleTimeout The period of time in milliseconds in which the recognizer must return a result after detection of speech Bargein Whether or not the playback of the prompt may be interrupted by the human listener CarrierGrammarURL URL of the grammar containing carrier phrases ClientActivationFunction Client-side function used to determine whether or not to activate the QA control. EndSilence Period of silence after the end of an utterance which must be free of speech after which recognition results are returned InitialTimeout The time in milliseconds between start of recognition and the detection of speech MaxTimeout The period of time in milliseconds between recognition start and results returned to the browser OnClientActiveFirst Client-side function called after control is determined to be active OnClientCompleteLast Client-side function called after execution of control (successfully or not) PostAnswerCarrierRule Name of the rule for the carrier phrase following an answer PreAnswerCarrierRule Name of the rule for the carrier phrase preceeding an answer PromptDatabase Name of the prompt database PromptSelectFunction Function that selects and/or modifies a prompt string prior to playback QuestionPrompt Prompt of the main question SpeechIndex Specifies control activation order ApplicationControl AllowDtmf Whether or not DTMF input is class allowed. AutoPostback Whether or not to post back to the server each time user interacts with the control CompleteLast Server-side function called when the CompleteLast event fires ConfirmThreshold The minimum confidence level of recognition necessary to mark an item as confirmed ConfirmRejectThreshold Rejection threshold for the confirmation phase in this control FirstInitialTimeout Initial timeout when QA.Count == 1 Mode Recognition mode to be followed OnClientActive Client-side function called after each internal QA is determined to be active OnClientComplete Client-side function called after execution of each internal QA (successfully or not) OnClientListening Client-side function called after successful start of the reco object PostConfirmCarrierRule Name of the rule for the carrier phrase following a confirm PreConfirmCarrierRule Name of the rule for the carrier phrase preceeding a confirm RejectThreshold Rejection threshold for this control StartElement ID of the GUI control whose event will activate recognition StartEvent Name of the GUI event that will activate recognition StopElement ID of the GUI control whose event will deactivate recognition StopEvent Name of the GUI event that will deactivate recognition SingleItemChooser DataBindField Name of the data field used for the text content of the list items DataMember The table used for binding when a DataSet is used as a data source DataSource The data source used to populate the control with items DataTextField Name of the data field used for the text content of the list items SemanticItem ID of the semantic item receiving the value spoken by the user Navigator Columns Collection of ColumnTemplate objects ContentTemplate Template that defines how contents are played DataContentFields Names of the data fields used to create the contents DataHeaderFields Names of the data fields used to create the headers DataMember The table used for binding when a DataSet is used as a data source DataSource The data source used to populate the control with items DisableColumnNavigation Whether or not navigating to column content is allowed HeaderTemplate Template that defines how headers are played InitialShortTimeout Time period before Silence event is fired SemanticItem ID of the semantic item receiving the value spoken by the user Currency PreferDollars Whether or not whole amounts are preferred when input is ambiguous AlphaDigit Grouping Enables/disables digit grouping input InputMask Defines constraints to character or range input SemanticItem ID of the semantic item receiving the value spoken by the user Numeral SemanticItem ID of the semantic item receiving the value spoken by the user LowerBound Smallest number accepted by the control UpperBound Largest number accepted by the control ValidationEvent When to validate that the number is within range Phone AreaCodeSemanticItem ID of the semantic item receiving the area code spoken by the user LocalNumberSemanticItem ID of the semantic item receiving the local number spoken by the user ExtensionSemanticItem ID of the semantic item receiving the extension spoken by the user StartElementAreaCode ID of the GUI control whose event starts recognition of the area code StopElementAreaCode ID of the GUI control whose event stops recognition of the area code StartElementLocalNumber ID of the GUI control whose event starts recognition of the local number StopElementLocalNumber ID of the GUI control whose event stops recognition of the local number StartElementExtension ID of the GUI control whose event starts recognition of the extension StopElementExtension ID of the GUI control whose event stops recognition of the extension StartEventAreaCode Name of the event that starts recognition of the area code part StopEventAreaCode Name of the event that stops recognition of the area code part StartEventLocalNumber Name of the event that starts recognition of the local number part StopEventLocalNumber Name of the event that stops recognition of the local number part StartEventExtension Name of the event that starts recognition of the extension part StopEventExtension Name of the event that stops recognition of the extension part RequiresAreaCode Determines whether or not the control asks for area code ZipCode ZipcodeSemanticItem ID of the semantic item receiving the zipcode spoken by the user ExtensionSemanticItem ID of the semantic item receiving the extension spoken by the user StartElementZipcode ID of the GUI control whose event starts recognition of the zipcode StopElementZipcode ID of the GUI control whose event stops recognition of the zipcode StartEventZipcode Name of the event that starts recognition of the zipcode StopEventZipcode Name of the event that stops recognition of the zipcode StartElementExtension ID of the GUI control whose event starts recognition of the extension StopElementExtension ID of the GUI control whose event stops recognition of the extension StartEventExtension Name of the event that starts recognition of the extension StopEventExtension Name of the event that stops recognition of the extension SocialSecurity SemanticItem ID of the semantic item Number receiving the number spoken by the user Separator Character that separates fields of the number Date DaySemanticItem ID of the semantic item receiving the day value spoken by the user MonthSemanticItem ID of the semantic item receiving the month value spoken by the user YearSemanticItem ID of the semantic item receiving the year value spoken by the user DateContext Sets the date preference of the control AllowRelativeDates Whether or not the control accepts dates like “today” AllowHolidays Whether or not the control accepts dates like “Christmas” AllowNumeralDates Whether or not the control accepts numeral formats like “eleven five sixty two” StartElementDay ID of the GUI control whose event starts recognition of the day StartEventDay Name of the event that starts recognition of the day StartElementMonth ID of the GUI control whose event starts recognition of the month StartEventMonth Name of the event that starts recognition of the month StartElementYear ID of the GUI control whose event starts recognition of the year StartEventYear Name of the event that starts recognition of the year StopElementDay ID of the GUI control whose event stops recognition of the day StopEventDay Name of the event that stops recognition of the day StopElementMonth ID of the GUI control whose event stops recognition of the month StopEventMonth Name of the event that stops recognition of the month StopElementYear ID of the GUI control whose event stops recognition of the year StopEventYear Name of the event that stops recognition of the year FallbackCount Maximum number of attemps at gathering full date before asking separately for day, month and year. YesNo SemanticItem ID of the semantic item receiving the value spoken by the user CreditCard NumberSemanticItem ID of the semantic item receiving the credit card number ExpirationMonthSemantic ID of the semantic item Item receiving the month of the credit card expiration date ExpirationYearSemantic ID of the semantic item Item receiving the year of the credit card expiration date AllowVISA Whether or not the control accepts VISA cards AllowDiscover Whether or not the control accepts Discover cards AllowMasterCard Whether or not the control accepts Mastercards AllowAmex Whether or not the control accepts American Express cards AllowDinersClub Whether or not the control accepts DinersClub cards DoubleConfirmation Whether or not to conduct a final confirmation StartElementCreditCard ID of the GUI control whose event starts recognition of the credit card number StartEventCreditCard Name of the event that starts recognition of the credit card number StopElementCreditCard ID of the GUI control whose event stops recognition of the credit card number StopEventCreditCard Name of the event that stops recognition of the credit card number StartElementExpiration ID of the GUI control whose Date event starts recognition of the credit card expiration date StartEventExpirationDate Name of the event that starts recognition of the credit card expiration date StopElementExpiration ID of the GUI control whose Date event stops recognition of the credit card expiration date StopEventExpirationDate Name of the event that stops recognition of the credit card expiration date | <SOH> BACKGROUND OF THE INVENTION <EOH>The present invention generally relates to encoding computers to perform a specific application. More particularly, the present invention relates to controls for defining an application to perform recognition and/or audible prompting such as a server that generates client side markup enabled with recognition and/or audible prompting. Small computing devices such as personal information managers (PIM), devices and portable phones are used with ever increasing frequency by people in their day-to-day activities. With the increase in processing power now available for microprocessors used to run these devices, the functionality of these devices are increasing, and in some cases, merging. For instance, many portable phones now can be used to access and browse the Internet as well as can be used to store personal information such as addresses, phone numbers and the like. In view that these computing devices are being used for browsing the Internet, or are used in other server/client architectures, it is therefore necessary to enter information into the computing device. Unfortunately, due to the desire to keep these devices as small as possible in order that they are easily carried, conventional keyboards having all the letters of the alphabet as isolated buttons are usually not possible due to the limited surface area available on the housings of the computing devices. To address this problem, there has been increased interest and adoption of using voice or speech to provide and access such information, particularly over a wide area network such as the Internet. Published U.S. patent application, U.S. 2003/0130854, entitled APPLICATION ABSTRACTION WITH DIALOG PURPOSE and U.S. patent application entitled APPLICATION ABSTRACTION WITH DIALOG PURPOSE having Ser. No. 10/426,053, filed Apr. 28, 2003 describe a method and system defining controls for a web server to generate client side markups that include recognition and/or audible prompting. Each of the controls perform a role in the dialog. For instance, controls can include prompt object used to generate corresponding markup for the client device to present information to the user, or generate markups for the client device to ask a question. An answer control or object generates markup for the client device so that a grammar used for recognition is associated with an input field related to a question that has been asked. If it is unclear whether or not a recognized result is correct, a confirmation mechanism can be activated and generate markup to confirm a recognized result. A command control generates markup that allows the user to provide commands, which are other than the expected answers to a specific question, and thus, allows the user to navigate through the web server application, for example. An application control provides a means to wrap common speech scenarios in one control. A module, when executed such as on a client, creates a dialog to solicit and provide information as a function of the controls. The module can use a control mechanism that identifies an order for the dialog, for example, an order for asking questions. The controls include activation logic that may activate other controls based on the answer given by the user. In many cases, the controls specify and allow the user to provide extra answers, which are commonly answers to questions yet to be asked, and thereby, cause the system to skip such questions since such answers have already been provided. This type of dialog is referred to as “mixed-initiative” since the system and the user have some control of dialog flow. The controls, when executed on a computer, generate client side markup for a client in a client/server system. A first set of visual controls have attributes for visual rendering on the client device, while a second set of controls have attributes related to at least one of recognition and audibly prompting. The application control is used to perform a selected task on the client device. The application control has properties for outputting controls of the second set to perform the selected task and associating the outputted controls with the first set of controls. In short, an application control, allows the application author to rapidly develop an application by using application controls rather than manually coding all the necessary syntax with the first and second set of controls to perform a selected task. The tasks can include obtaining information, e.g. numbers, characters, dates etc., or navigating a table of information. The application that is developed may include various built-in prompts, grammars and dialog flow or generate these features automatically. Use of the application controls saves time and thereby cost in developing the application. However, although the application controls provide helpful building block mechanisms for implementing a recognition based application, the controls are not particularly well suited for a mixed-initiative dialogue where the user provides information that eventually will be required, but does so before such questions are asked. Improved methods or techniques to better handle mixed-initiative dialogue in a convenient manner would thus be helpful. | <SOH> SUMMARY OF THE INVENTION <EOH>Controls are provided for a web server to generate client side markups that include recognition and/or audible prompting. The controls comprise elements of a dialog such as a question, answer, confirmation, command or statement. A module forms a dialog by making use of the information carried in the controls. Each of the controls perform a role in the dialog. For instance, controls can include prompt object used to generate corresponding markup for the client device to present information to the user, or generate markups for the client device to ask a question. An answer control or object generates markup for the client device so that a grammar used for recognition is associated with an input field related to a question that has been asked. If it is unclear whether or not a recognized result is correct, a confirmation mechanism can be activated and generate markup to confirm a recognized result. A module, when executed such as on a client, creates a dialog to solicit and provide information as a function of the controls. An aspect of the present invention is to allow the speech controls to refer to other speech controls such that elements can be combined or re-used. This allows more rapid design of the application in that common need not be repeated. In addition, the resulting application is better equipped to handle mixed-initiative dialogues. | 20040110 | 20090623 | 20050915 | 92111.0 | 0 | LERNER, MARTIN | DIALOG COMPONENT RE-USE IN RECOGNITION SYSTEMS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,755,999 | ACCEPTED | Slug pulling preventing tooling die | A punch and die tooling apparatus commonly used by metal fabricators for creating holes, passages and cavities in metal plate, the die having a unique internal bore which relieves the problem of slug pulling to ensure that a slug punched out of a metal sheet is not retained on the punch face to interfere with further operation of the apparatus. The die is provided with a substantially horizontal ridge and a corresponding horizontal land and relief space formed within the bore to facilitate tipping of the slug relative to the punch and thereby break any attachment between the slug and the punch face which causes slug pulling. | 1. A punch and die tooling apparatus comprising: a punch and a die for forming a hole in a metal plate; a die body defining a vertical through bore extending between a top and a bottom surface of the die body; a horizontally extending ridge formed on a first portion of a wall of the through bore for engaging a portion of a slug cut from the metal plate and tipping the slug away from a face of the punch; a partially circumferential relief formed on a second portion of the wall substantially opposite from the horizontally extending ridge to facilitate the tipping of the slug away from the face of the punch. 2. The punch and die tooling apparatus as set forth in claim 1, wherein the partially circumferential relief is formed vertically closer to the top surface of the die body than the horizontally extending ridge to provide an adequate space to prevent jamming of the tipping slug in the through bore of the die. 3. The punch and die tooling apparatus as set forth in claim 1, wherein the partially circumferential relief defines a relief area extending between the circumferential relief and the bottom surface of the die body. 4. The punch and die tooling apparatus as set forth in claim 1, wherein the horizontally extending ridge and the partially circumferential relief are formed by an overlapping upper and lower offset bores. 5. The punch and die tooling apparatus as set forth in claim 4, wherein the lower bore is larger than the upper bore. 6. A die for a punch and die tooling apparatus comprising: a die body defining a through bore extending between a top and a bottom surface of the die body, the through bore further comprising; an upper bore defining a cutting edge on the top surface of the die body and extending partially through the die along a first longitudinal axis; a lower bore defining a bottom opening on the bottom surface of the die and extending partially through the die along a second longitudinal axis to connect with the top bore; wherein the second longitudinal axis is parallel to and offset from the first axis to form a first and a second opposing ledges at an intersection of the upper and lower bores in the through bore. 7. The die as set forth in claim 6 further comprising an overlapping section of the upper and lower bores formed at an intermediate portion of the through bore to define a longitudinal spacing between the first and second opposing ledges. 8. The die as set forth in claim 6 wherein the lower bore is formed having a slightly larger diameter than the upper bore. 9. The die as set forth in claim 6 wherein the first ledge is formed having a larger radial area and a longer circumferential length than the opposing second ledge. 10. The die as set forth in claim 9 wherein the first ledge defines a first substantially horizontal surface area defining an area of relief in the through bore extending downwards from the first substantially horizontal surface area to the bottom opening of the lower bore. 11. A method of forming a die for a punch and die tooling machine comprising the steps of: forming a through bore in a die body extending between a top and a bottom surface of the die body, the formation of the through bore further comprising the steps of; machining a lower bore in the die body to define a bottom opening on the bottom surface of the die and extending partially through the die along a second longitudinal axis parallel to and offset from the first axis to form; machining an upper bore in the die body to define a cutting edge on the top surface of the die body and extending partially through the die along a first longitudinal axis to connect the upper bore and the lower bore; and overlapping the upper bore with the lower bore to create a first and a second opposing ledges at an intersection of the upper and lower bores within the through bore. | FIELD OF THE INVENTION The present invention relates to a punch and die tooling apparatus commonly used by metal fabricators for creating holes, passages and cavities in metal plate. In particular, the present invention relates to a die for such an apparatus having a unique internal bore which relieves the problem of slug pulling, i.e. ensures that a slug punched out of a metal sheet is not retained on the punch face to interfere with further operation of the apparatus. More specifically, the die is provided with a substantially horizontal ridge and a corresponding horizontal land and relief space formed within the bore to facilitates tipping of the slug relative to the punch and thereby break any attachment between the slug and the punch face which causes slug pulling. BACKGROUND OF THE INVENTION Punch and dies have been used for decades by metal fabricators as a common process for creating holes in metal plate. The die usually has a surface and above defining a cutting edge upon which the metal plate is positioned. The male punch element which, moves generally perpendicular relative to the female die and metal plate thereon, is concentrically aligned with the die bore. The punch is pressed through the steel plate and into the bore, creating a hole in the plate and cutting a slug from the metal plate material. The slug should either be frictionally retained inside the die or the slug should drop off the punch face so the punch can recycle to produce another hole and slug in a subsequent cycle of the punch press. Slug retention or slug pulling as it is commonly known is a significant problem with such tool and die apparatus. Slug pulling will cause machine down time as well as material, tool and machine damage. Slug pulling occurs when the slug does not separate from the punch face, but actually gets pulled fully or partially up by the punch and out of the die as the punch cycles on an up-stroke. A number of factors can cause slug pulling. A lubricant is usually used to reduce wear and keep the punch and die sets in good condition as well as to reduce the tonnage required to punch a hole. These lubricants can create a vacuum effect between the flat face of the punch and the top of the slug. Lighter oils i.e. generally oils of lower viscosity, may reduce the vacuum effect to some extent, but slug pulling still occurs. Furthermore, lighter oils vaporize and are messy. Also, as the punch begins to wear, a raised butt is created on top of the slug that can “hug” or wrap itself around the punch adhering to the punch to cause slug pulling. It is also possible for the punch to become magnetized, thus causing an undesired adherence of the slug to the slug face. Tool and die manufacturer's solutions generally use the concept of trying to retain the slug in the die by use of friction. By way of example, if the slug is squeezed in the bore hole of the die tight enough, the slug friction will be greater than the vacuum between the slug and the punch face on the up stroke of the punch cycle. Known friction die add internal vertical ridges or slightly off vertical ridges on the walls of the die bore, i.e., ridges or ribs which run substantially parallel with the longitudinal axis of the bore hole. Other known devices utilize protrusions in the bore, for example a tapered pressure point or points. None of these solutions have been shown to be particularly effective as slug pulling can still occur, and as the internal ridges or pressure points wear, the slug pulling problem gets worse. SUMMARY OF THE INVENTION Wherefore, it is an object of the present invention to eliminate the problem of slug retention and slug pulling by punch and die machines when creating holes in metal plate. Another object of the present invention is to provide a partially circumferential ridge and a relief area formed substantially horizontally relative to the longitudinal axis of the die bore in order to facilitate the elimination of slug retention by the punch. A still further object of the present invention is to form the ridge and land by providing partially offset die bores or non-concentrically machined top and bottom die bores. A yet still further object of the present invention is to provide such an offset bore by forming a lower bore section which is slightly larger in diameter and offset from the center longitudinal axis of a top bore section formed in the die. A still further object of the present invention is to initially form the larger diameter offset lower bore section and then form the slightly smaller top bore to overlap the lower bore section and create a relative longitudinal spacing between the ridge area and the relief area that forces the slug to deflect or tilt thereby breaking any bond between the slug and a face of the tooling punch. Another object of the present invention is to eliminate slug pulling and slug retention by providing a long lasting, wear resistant die which is economical and can be easily mass produced and that the performance of the die with respect to elimination of slug pulling is heightened the more that the die is used due to wear off the sharp edges formed by the offset die bores. The present invention also relates to a die for a punch and die tooling apparatus comprising a die body defining a through bore extending between a top and a bottom surface of the die body, the through bore further comprising an upper bore defining a cutting edge on the top surface of the die body and extending partially through the die along a first longitudinal axis, a lower bore defining a bottom opening on the bottom surface of the die and extending partially through the die along a second longitudinal axis to connect with the top bore, wherein the second longitudinal axis is parallel to and offset from the first axis to form a first and a second opposing ledges at an intersection of the upper and lower bores in the through bore. The present invention also relates to a method of forming a die for a punch and die tooling machine comprising the steps of forming a through bore in a die body extending between a top and a bottom surface of the die body, the formation of the through bore further comprising the steps of machining a lower bore in the die body to define a bottom opening on the bottom surface of the die and extending partially through the die along a second longitudinal axis parallel to and offset from the first axis, machining an upper bore in the die body to define a cutting edge on the top surface of the die body and extending partially through the die along a first longitudinal axis to connect the upper bore and the lower bore, and overlapping the upper bore with the lower bore to create a first and a second opposing ledges at an intersection of the upper and lower bores within the through bore. BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described, by way of example, with reference to the accompanying drawings in which: FIG. 1 is an elevation view of a punch, die and metal sheet prior to hole formation; FIG. 2 is a cutaway elevation view of the tooling die of the present invention a metal plate, and a slug cut from the metal plate; FIG. 3a-b are respective top and bottom plan views of the tooling die; FIG. 4a-b are side and cross-sectional side views respectively of the die; FIG. 5a-d are a sequence of punch an die cutting operations; FIG. 6 is a perspective view of the die according to the present invention; and FIG. 7a-b are examples of similar and different diameter top and bottom offset axes. DETAILED DESCRIPTION OF THE INVENTION A punch and die machine, as well known in the art, is provided with a punch and a die for forming holes in metal plate. Observing FIG. 1, a punch 1 is shown positioned above, and relatively spaced above a die 3 and metal plate 7. The punch 1 is provided with a point 5 extending downward to define a longitudinal axis A along which the punch 1 generally travels in a substantially vertical, or up and down motion. The point 5 has a diameter which is substantially the same size as a hole to be formed in the metal plate 7, and at a free end of the point 5 a substantially flat, horizontally aligned and relatively flat face 9 is formed to directly contact and cut the metal plate 7. The die 3 is positioned generally below the punch 1, and the die bore 11 is provided with a diameter which is at least slightly larger than the point 5 of the punch 1 to permit the face 9 and point 5 to penetrate into the die bore 11 along the longitudinal axis A. As is well understood by those in the art, the depth to which the punch 1 is permitted to penetrate the die bore 11 can be controlled by mechanisms on the punch and die apparatus and, therefore, may be set to any desired depth often dependent upon the thickness of the steel plate being cut. The metal plate 7 has a particular thickness T and is positioned between the punch 1 and the die 3 and generally perpendicular to the axis A along which the punch 1 and die 3 are aligned. The plate 7 is positioned on a top surface 13 of the die 3 which defines a top cutting edge 15 formed where the die bore 11 intersects the top surface 13. Turning to FIG. 2, a slug 17, having been cut by the punch 1 (not shown here), is shown passing through the die bore 11. In order to eliminate the slug pulling and slug retention as discussed in the Background of the Invention, the die bore 11 is formed in a unique manner to cause the slug 17, during cycling of the punch 1 through the metal plate 7, to tip relative to the horizontal face 9 of the punch 1, thus breaking any bond between the slug 17 and the face 9 of the punch 1. To accomplish this relative tipping of the slug 17, a further discussion of which will be provided below, a substantially horizontal ridge 19 or ledge is created in a wall of the die bore 11. The ridge 19 forms a substantially horizontal, upwardly facing ridge surface 21 aligned-perpendicular to the longitudinal axis A and relative vertical path of the slug 17 through the die bore 11. Substantially opposite to the ridge surface 21 in the die bore 11, in other words on the opposite side of the die bore wall, approximately 180 degrees from the ridge 19, a relief 23 is partially circumferentially formed in the die wall. The relief 23 is defined by a substantially horizontally and downward facing relief surface 25 relative to the downward path of the slug 17. Observing FIGS. 3a-b and 4a-b, the relief surface 25 also is usually provided with a longer radial length l′ than a radial length Q″ of the ridge surface 21 as seen in FIG. 3a, and is also longitudinally, i.e., axially spaced from the top surface 13 and cutting edge 15 of the die 3 a distance h′ as seen in FIG. 4a. In addition, as shown in FIG. 4a, the relief surface 25 is generally formed higher on the wall of the die bore 11 than the ridge 19 and ridge surface 21, in other words, the downward facing relief surface 25 is longitudinally or axially positioned between the cutting edge 15 of the die 3, and the slug tipping ridge surface 21 to permit the top edge portion 33 of the slug 17 to tip from the horizontal and not jam against the inner wall of the die bore 11. The ridge 19 is longitudinally spaced from the top surface 13 and cutting edge 15 of the die 3 a distance h″ and extends partially around the circumference of the wall of the die bore 11. Another way of defining the die bore 11 of the present invention is that the die bore 11 itself is composed of a top bore 27 and an offset bottom bore 29. The top bore 27 extends down from the top surface 13 of the die 3 the distance h″, and the bottom bore 29 extends upwards from the bottom surface 14 of the die 3 to the distance h′ from the top surface 27. As can be seen in FIG. 4a-b, this results in a degree of overlap O of the top bore 27 and bottom bore 29. It is to be appreciated that this overlap O in combination with an offset O′ as defined by the offset center axis X of bottom bore 29, to be discussed in further detail below, produce the ridge surface 21 and relief surface 25 discussed above. In addition to the radial length l′ of the downward facing relief surface 25 being longer than the radial length l″ of the ridge surface 21, as seen in FIGS. 3a-b, the area of the downward facing relief surface 25 may be larger than the area of the upwardly facing ridge surface 21. This is an important aspect of the present invention as the relief surface 25, its radial length l′ and the longitudinal spacing of the relief surface 25 from the opposing ridge surface 21 must define a relief area 23 in the die bore 11 which will permit the tipping of the slug 17 in the die bore 11 relative to the horizontal point face 9 and the longitudinal axes A, X when a bottom portion of the slug 17 encounters the ridge surface 21 causing the slug 17 to tip. Because the slug 17 is essentially cut to the same diameter as the top bore 27, the relief area 23 provides room for the slug 17 to be tipped relative to the longitudinal axes A, X within the die bore 11. This aspect of the present invention may be better achieved by the difference in respective diameters between the top bore 27 and bottom bore 29. Turning to FIG. 5a-d, a description of the above discussed features of the present invention in conjunction with a downward cycle of the punch 1 and the forming of a hole in the steel plate 7 is provided. A metal plate 7 is positioned on the top surface 13 of the die and the punch 1 is driven downward along the axis A. In FIG. 5b, the punch face 9 has been brought downwards into contact with the metal plate 7, as shown by the arrow and, with the aid of the opposing cutting edge 15 on the top surface 13 of the die 3, cuts a slug 17 from the metal plate 7. The punch face 9, still being in contact with the slug 17, begins pushing the slug 17 into the die bore 11. FIG. 5c shows the punch point 5 and face 9 having pushed the slug 17 clear of a bottom surface 14 of the metal plate 7 and the punch face 9 having passed through the thickness T of the metal plate 7 to force a lower edge portion 31 of the slug 17 into contact with the ridge surface 21 in the die bore 11. The contact between the lower edge portion of the slug 31 and the upwardly facing ridge surface 21 causes a relative tipping of the slug 17 with respect to the axis A and the face of the punch 9. As can be seen in FIG. 5c, the top surface of the slug 13 and the face 9 of the punch point 5 are caused to separate by the tipping action of the slug 17. In order to facilitate the tipping of the slug 17, and to ensure that the tipping of the slug 17 does not cause the slug 17 to become jammed in the die bore 11, the relief surface 25 and relief area 23 permit the top edge portion 33 of the slug 17 to pass under the relief surface 25 and rotate radially outward relative to the upper top bore 27. Thus, in view of the relief surface 25 and relief area 23 defined thereby, the slug 17 is permitted to tip freely relative to the horizontal nature of the point face 9 as it is cut from the metal plate 7. The relief area 23 permits the slug 17 to be tipped downwards by providing a larger wall clearance in a lower portion 29 of the die bore 11. FIG. 5d details the continued movement of the punch point 5 penetrating into the die 3 and pushing the slug 17 past the ridge 19 and relief surfaces 25 and out of the die 3. It is to be appreciated that as the top surface of the slug 13 is now tipped or angled with respect to the face 9 of the punch 1. With such separation, no seal or attachment of the slug 17 to the punch face 9 can occur from the relative viscosity of lubricant oils, nor should any type of molecular, magnetic or other bonding between the punch face 9 and the slug 17 also occur. The slug 17 then falls freely downward through the die 3 and away from the punch point 5 as the punch point 5 is returned to the initial starting position above the metal plate 7 and die 3. Thus the forced separation between the punch face 9 and the metal slug 17 substantially eliminates the possibility of slug pulling and thus the punch 1 can be cycled back to an initial raised position above the metal plate 7 and die 3 without a slug attached thereto. It is to be appreciated that as the punch 1 comes down, i.e. is applied to the metal plate with the desired amount of tonnage necessary to cut the plate, a significant vacuum/suction or bond is often created between the slug 17 and the punch face 9. The initial contact with the ridge surface 21 as the bottom edge portion 31 of the slug 17 encounters the ridge surface 21 in the die bore 11 impedes the lower edge portion 31 of the slug causing, in most instances, the suction or bond to break and the slug 17 to tip. However, even if the bond or attachment is not completely broken, the slug 17 is forced radially over to the relief 23 or clearance side of the bottom die bore 29 upon hitting the ridge 19 and cannot be pulled back up because of the taper of the slug 17 as well as the fact that upon withdrawal of the punch point 5 from the die bore 11, the top edge portion 33 the slug 17 will encounter the downward facing relief surface 25 as it is pulled up, and thus the bond will be broken as the slug 17 is essentially shaved off the withdrawing punch face 9 as the punch 1 is cycled upwards out of the die bore 1. Turning to FIG. 6, a method for forming the ridge 19 and the relief 23 in the die 3, as shown here in perspective view, is now provided. The above discussed features may be formed in any number of ways or method as are known in the art. An example of a preferred method by which the ridge surface 21 and relief surface 25 may be formed in the die bore 11 is as follows. Provided with a blank die, i.e., merely a solid metal block having no hole or bore therethrough, the top bore center line, or longitudinal axis A determined by any method as well known in the art. With the center line A known and marked on the top surface 13 and bottom surface of the die blank, a second offset die bore axis X is determined at a desired offset O from the top bore centerline A, i.e., radially spaced therefrom. With the offset die bore axis X marked on the bottom surface 14 of the die 3, the offset bottom bore 29 is first formed along the die bore axis X, by machining or drilling as known in the art, from the bottom surface 14 of the die 3 partially through the die to a distance h′ from the top surface of the die 13. The top portion 27 of the die bore 11 is then formed along the axis A, by machining or drilling usually, from the top surface 13 of the die 3 along the center line A of the top bore 27. The top bore 27 of the die bore 11 is machined from the top surface 13 of the die blank through to connect with and meet the bottom bore 29. Furthermore, the top bore 27 is machined a distance h″ to overlap a distance O with the bottom bore 29. Because the top bore 27 is centered along the axis A at the center point of the die blank and overlaps the bottom bore 29, a first portion of the top bore 27 at the intersection with the lower bore 29 thus creates the overhang, or downwardly facing relief surface 25 on the wall of the die bore 11. A second portion of the top bore 27 does not intersect the lower die bore 29, but continues cutting through the die 3 opposite to the relief surface 25 to a desired depth even after the intersection of the top and bottom bores 27, 29, respectively, this continued cutting of the die 3 creates the upwardly facing ridge 19 surface at the depth h″ where the top bore 27 essentially ends. The top bore 27 is machined to a desired depth h″ overlapping to a desired extent with the bottom bore 29 so that a complete passageway is formed through the die 3. Due to the offset nature of the top and bottom bore 27, 29, and the overlapping nature of the top and bottom bores 27, 29, as can be seen in FIG. 6, the upwardly facing ridge surface 19 is formed essentially where the top bore 27 machining process is stopped. The ridge 19 having an upward facing substantially horizontal surface 21 relative to the longitudinal axis A along which the punch 1 will operate. Because of the overlapping nature of the top and bottom bores 27, 29 the ridge surface 21 and the relief surface 25 are also longitudinally spaced apart, with the relief area 23 being formed substantially at the end of the bottom bore 29, and the ridge area 23 being formed at the upper end of the top bore 27 and the ridge area being formed at the lower end of the top bore 27 and radially opposite from the relief surface 25. As is known in the art, the top die bore 11 can be any desired size depending on the holes to be formed in the metal plate 7. In particular, the top bore 27 is machined to be substantially the same size as the hole to be formed in the metal plate 7 and slightly larger than the diameter of the die punch face 9 and point 5 in order to accommodate the penetration of the punch 1 into the die 3. The diameter of the point 5 and face 9 of the punch 1 is also formed substantially the same size as the hole which is to be formed in the metal plate 7, but slightly smaller than the diameter of the top bore 27 so as to fit therein. As the bore 11 and punch point 5 diameters may vary in particular with any desired size of hole to be formed in a metal plate 7 as is well known in the art no further discussion is provided herein. However, it is to appreciated that the relative diameters of the top bore 27 and bottom bore 29 forming the complete die bore 11, can be substantially the same as seen in FIG. 7a, or can be slightly different in size as shown in FIG. 7b. For example, an offset O of the same size, i.e., same radius r, of the top and bottom bores 27, 29 will produce equal areas of ridge surface 21 and relief surface 25. However, it is also to be appreciated that a larger bottom bore 29 having a radius R relative to the top bore 27 having a smaller radius r, will create a difference in area between the ridge surface 21 and the opposing relief surface 25. Where a larger radius R bottom bore 29 is used, a larger relief surface 25 area is formed relative to the ridge surface area 21. Such an arrangement ensures sufficient clearance and relief within the die bore 11 to accommodate the tipping slug 17, whereas only a slight ridge area is generally necessary to actually initiate the tipping of the slug 17 relative to the die punch face 9. A more specific ratio range of relative size of the offset bottom bore 29, where the top bore 27 size is known for purposes of cutting the slug and hole, may be in the range of about 1 to 1.5, and more preferably in the range of 1.01 to 1.2 and even more preferably about 1.02 to 1.1. Since certain changes may be made in the above described improved tooling die, without departing from the spirit and scope of the invention herein involved, it is intended that all of the subject matter of the above description or shown in the accompanying drawings shall be interpreted merely as examples illustrating the inventive concept herein and shall not be construed as limiting the invention. | <SOH> BACKGROUND OF THE INVENTION <EOH>Punch and dies have been used for decades by metal fabricators as a common process for creating holes in metal plate. The die usually has a surface and above defining a cutting edge upon which the metal plate is positioned. The male punch element which, moves generally perpendicular relative to the female die and metal plate thereon, is concentrically aligned with the die bore. The punch is pressed through the steel plate and into the bore, creating a hole in the plate and cutting a slug from the metal plate material. The slug should either be frictionally retained inside the die or the slug should drop off the punch face so the punch can recycle to produce another hole and slug in a subsequent cycle of the punch press. Slug retention or slug pulling as it is commonly known is a significant problem with such tool and die apparatus. Slug pulling will cause machine down time as well as material, tool and machine damage. Slug pulling occurs when the slug does not separate from the punch face, but actually gets pulled fully or partially up by the punch and out of the die as the punch cycles on an up-stroke. A number of factors can cause slug pulling. A lubricant is usually used to reduce wear and keep the punch and die sets in good condition as well as to reduce the tonnage required to punch a hole. These lubricants can create a vacuum effect between the flat face of the punch and the top of the slug. Lighter oils i.e. generally oils of lower viscosity, may reduce the vacuum effect to some extent, but slug pulling still occurs. Furthermore, lighter oils vaporize and are messy. Also, as the punch begins to wear, a raised butt is created on top of the slug that can “hug” or wrap itself around the punch adhering to the punch to cause slug pulling. It is also possible for the punch to become magnetized, thus causing an undesired adherence of the slug to the slug face. Tool and die manufacturer's solutions generally use the concept of trying to retain the slug in the die by use of friction. By way of example, if the slug is squeezed in the bore hole of the die tight enough, the slug friction will be greater than the vacuum between the slug and the punch face on the up stroke of the punch cycle. Known friction die add internal vertical ridges or slightly off vertical ridges on the walls of the die bore, i.e., ridges or ribs which run substantially parallel with the longitudinal axis of the bore hole. Other known devices utilize protrusions in the bore, for example a tapered pressure point or points. None of these solutions have been shown to be particularly effective as slug pulling can still occur, and as the internal ridges or pressure points wear, the slug pulling problem gets worse. | <SOH> SUMMARY OF THE INVENTION <EOH>Wherefore, it is an object of the present invention to eliminate the problem of slug retention and slug pulling by punch and die machines when creating holes in metal plate. Another object of the present invention is to provide a partially circumferential ridge and a relief area formed substantially horizontally relative to the longitudinal axis of the die bore in order to facilitate the elimination of slug retention by the punch. A still further object of the present invention is to form the ridge and land by providing partially offset die bores or non-concentrically machined top and bottom die bores. A yet still further object of the present invention is to provide such an offset bore by forming a lower bore section which is slightly larger in diameter and offset from the center longitudinal axis of a top bore section formed in the die. A still further object of the present invention is to initially form the larger diameter offset lower bore section and then form the slightly smaller top bore to overlap the lower bore section and create a relative longitudinal spacing between the ridge area and the relief area that forces the slug to deflect or tilt thereby breaking any bond between the slug and a face of the tooling punch. Another object of the present invention is to eliminate slug pulling and slug retention by providing a long lasting, wear resistant die which is economical and can be easily mass produced and that the performance of the die with respect to elimination of slug pulling is heightened the more that the die is used due to wear off the sharp edges formed by the offset die bores. The present invention also relates to a die for a punch and die tooling apparatus comprising a die body defining a through bore extending between a top and a bottom surface of the die body, the through bore further comprising an upper bore defining a cutting edge on the top surface of the die body and extending partially through the die along a first longitudinal axis, a lower bore defining a bottom opening on the bottom surface of the die and extending partially through the die along a second longitudinal axis to connect with the top bore, wherein the second longitudinal axis is parallel to and offset from the first axis to form a first and a second opposing ledges at an intersection of the upper and lower bores in the through bore. The present invention also relates to a method of forming a die for a punch and die tooling machine comprising the steps of forming a through bore in a die body extending between a top and a bottom surface of the die body, the formation of the through bore further comprising the steps of machining a lower bore in the die body to define a bottom opening on the bottom surface of the die and extending partially through the die along a second longitudinal axis parallel to and offset from the first axis, machining an upper bore in the die body to define a cutting edge on the top surface of the die body and extending partially through the die along a first longitudinal axis to connect the upper bore and the lower bore, and overlapping the upper bore with the lower bore to create a first and a second opposing ledges at an intersection of the upper and lower bores within the through bore. | 20040113 | 20070501 | 20050714 | 85601.0 | 0 | PRONE, JASON D | SLUG PULLING PREVENTING TOOLING DIE | SMALL | 0 | ACCEPTED | 2,004 |
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10,756,158 | ACCEPTED | Differential dynamic content delivery with prerecorded presentation control instructions | Methods, systems, and computer program products are disclosed for differential dynamic content delivery. Typical embodiments include providing a session document for a presentation, wherein the session document includes a session grammar and a session structured document; receiving a prerecorded presentation control instruction; selecting from the session structured document a classified structural element in dependence upon the prerecorded presentation control instruction and in dependence upon user classifications of a user participant in the presentation; and presenting the selected structural element to the user. In typical embodiments, the prerecorded presentation control instruction has an associated time stamp. | 1. A method for differential dynamic content delivery, the method comprising: providing a session document for a presentation, wherein the session document includes a session grammar and a session structured document; receiving a prerecorded presentation control instruction; selecting from the session structured document a classified structural element in dependence upon the prerecorded presentation control instruction and in dependence upon user classifications of a user participant in the presentation; and presenting the selected structural element to the user. 2. The method of claim 1 wherein the prerecorded presentation control instruction has an associated time stamp. 3. The method of claim 1 further comprising creating a prerecorded presentation session, including repeatedly: recording a presentation control instruction; and recording a time stamp in association with the presentation control instruction. 4. The method of claim 3 further comprising creating the presentation control instruction, including: receiving from a user participating in the presentation a key phrase and optional parameters for invoking a presentation action; and parsing the key phrase and parameters against a voice response grammar into a presentation control instruction. 5. The method of claim 1 wherein: the prerecorded presentation control instruction includes a presentation action identifier and optional parameters; and selecting a classified structural element includes selecting a classified structural element in dependence upon the presentation action identifier and the parameters. 6. The method of claim 1 wherein selecting a classified structural element further comprises selecting a classified structural element having an associated classification identifier that corresponds to the user classification. 7. The method of claim 1 wherein presenting the selected structural element to the user further comprises: selecting a data communications protocol for the presentation; inserting the selected structural element in a data structure appropriate to the data communications protocol; and transmitting the data structure to the user according to the data communications protocol. 8. The method of claim 1 further comprising creating a session document from a presentation document, including: identifying a presentation document for a presentation, the presentation document including a presentation grammar and a structured document having structural elements classified with classification identifiers; identifying a user participant for the presentation, the user having a user profile comprising user classifications; and filtering the structured document in dependence upon the user classifications and the classification identifiers. 9. The method of claim 8 wherein filtering the structured document comprises: extracting, from the structured document, structural elements having classification identifiers corresponding to the user classifications; and writing the extracted structural elements into a session structured document in the session document. 10. The method of claim 9 further comprising filtering the presentation grammar, in dependence upon the extracted structural elements, into a session grammar in the session document. 11. The method of claim 8 further comprising creating a presentation document, including: creating, in dependence upon an original document, a structured document comprising one or more structural elements; classifying a structural element of the structured document according to a presentation attribute; and creating a presentation grammar for the structured document, wherein the presentation grammar for the structured document includes grammar elements each of which includes an identifier for at least one structural element of the structured document. 12. The method of claim 11 wherein classifying a structural element comprises: identifying a presentation attribute for the structural element; identifying a classification identifier in dependence upon the presentation attribute; and inserting the classification identifier in association with the structural element in the structured document. 13. The method of claim 11 wherein creating a presentation grammar for the structured document comprises: identifying the content type of the original document; selecting, in dependence upon the content type, a full presentation grammar from among a multiplicity of full presentation grammars; and filtering the full presentation grammar into a presentation grammar for the structured document in dependence upon the structural elements of the structured document. 14. A system for differential dynamic content delivery, the system comprising: means for providing a session document for a presentation, wherein the session document includes a session grammar and a session structured document; means for receiving a prerecorded presentation control instruction; means for selecting from the session structured document a classified structural element in dependence upon the prerecorded presentation control instruction and in dependence upon user classifications of a user participant in the presentation; and means for presenting the selected structural element to the user. 15. The system of claim 14 wherein the prerecorded presentation control instruction has an associated time stamp. 16. The system of claim 14 further comprising means for creating a prerecorded presentation session, including: means for recording a presentation control instruction; and means for recording a time stamp in association with the presentation control instruction. 17. The system of claim 16 further comprising means for creating the presentation control instruction, including: means for receiving from a user participating in the presentation a key phrase and optional parameters for invoking a presentation action; and means for parsing the key phrase and parameters against a voice response grammar into a presentation control instruction. 18. The system of claim 14 wherein: the prerecorded presentation control instruction includes a presentation action identifier and optional parameters; and means for selecting a classified structural element includes means for selecting a classified structural element in dependence upon the presentation action identifier and the parameters. 19. The system of claim 14 wherein means for selecting a classified structural element further comprises means for selecting a classified structural element having an associated classification identifier that corresponds to the user classification. 20. The system of claim 14 wherein means for presenting the selected structural element to the user further comprises: means for selecting a data communications protocol for the presentation; means for inserting the selected structural element in a data structure appropriate to the data communications protocol; and means for transmitting the data structure to the user according to the data communications protocol. 21. The system of claim 14 further comprising means for creating a session document from a presentation document, including: means for identifying a presentation document for a presentation, the presentation document including a presentation grammar and a structured document having structural elements classified with classification identifiers; means for identifying a user participant for the presentation, the user having a user profile comprising user classifications; and means for filtering the structured document in dependence upon the user classifications and the classification identifiers. 22. The system of claim 21 wherein means for filtering the structured document comprises: means for extracting, from the structured document, structural elements having classification identifiers corresponding to the user classifications; and means for writing the extracted structural elements into a session structured document in the session document. 23. The system of claim 22 further comprising means for filtering the presentation grammar, in dependence upon the extracted structural elements, into a session grammar in the session document. 24. The system of claim 21 further comprising means for creating a presentation document, including: means for creating, in dependence upon an original document, a structured document comprising one or more structural elements; means for classifying a structural element of the structured document according to a presentation attribute; and means for creating a presentation grammar for the structured document, wherein the presentation grammar for the structured document includes grammar elements each of which includes an identifier for at least one structural element of the structured document. 25. The system of claim 24 wherein means for classifying a structural element comprises: means for identifying a presentation attribute for the structural element; means for identifying a classification identifier in dependence upon the presentation attribute; and means for inserting the classification identifier in association with the structural element in the structured document. 26. The system of claim 24 wherein means for creating a presentation grammar for the structured document comprises: means for identifying the content type of the original document; means for selecting, in dependence upon the content type, a full presentation grammar from among a multiplicity of full presentation grammars; and means for filtering the full presentation grammar into a presentation grammar for the structured document in dependence upon the structural elements of the structured document. 27. A computer program product for differential dynamic content delivery, the computer program product comprising: a recording medium; means, recorded on the recording medium, for providing a session document for a presentation, wherein the session document includes a session grammar and a session structured document; means, recorded on the recording medium, for receiving a prerecorded presentation control instruction; means, recorded on the recording medium, for selecting from the session structured document a classified structural element in dependence upon the prerecorded presentation control instruction and in dependence upon user classifications of a user participant in the presentation; and means, recorded on the recording medium, for presenting the selected structural element to the user. 28. The computer program product of claim 14 wherein the prerecorded presentation control instruction has an associated time stamp. 29. The computer program product of claim 14 further comprising means, recorded on the recording medium, for creating a prerecorded presentation session, including: means, recorded on the recording medium, for recording a presentation control instruction; and means, recorded on the recording medium, for recording a time stamp in association with the presentation control instruction. 30. The computer program product of claim 16 further comprising means, recorded on the recording medium, for creating the presentation control instruction, including: means, recorded on the recording medium, for receiving from a user participating in the presentation a key phrase and optional parameters for invoking a presentation action; and means, recorded on the recording medium, for parsing the key phrase and parameters against a voice response grammar into a presentation control instruction. 31. The computer program product of claim 14 wherein: the prerecorded presentation control instruction includes a presentation action identifier and optional parameters; and means, recorded on the recording medium, for selecting a classified structural element includes means, recorded on the recording medium, for selecting a classified structural element in dependence upon the presentation action identifier and the parameters. 32. The computer program product of claim 14 wherein means, recorded on the recording medium, for selecting a classified structural element further comprises means, recorded on the recording medium, for selecting a classified structural element having an associated classification identifier that corresponds to the user classification. 33. The computer program product of claim 14 wherein means, recorded on the recording medium, for presenting the selected structural element to the user further comprises: means, recorded on the recording medium, for selecting a data communications protocol for the presentation; means, recorded on the recording medium, for inserting the selected structural element in a data structure appropriate to the data communications protocol; and means, recorded on the recording medium, for transmitting the data structure to the user according to the data communications protocol. 34. The computer program product of claim 14 further comprising means, recorded on the recording medium, for creating a session document from a presentation document, including: means, recorded on the recording medium, for identifying a presentation document for a presentation, the presentation document including a presentation grammar and a structured document having structural elements classified with classification identifiers; means, recorded on the recording medium, for identifying a user participant for the presentation, the user having a user profile comprising user classifications; and means, recorded on the recording medium, for filtering the structured document in dependence upon the user classifications and the classification identifiers. 35. The computer program product of claim 21 wherein means, recorded on the recording medium, for filtering the structured document comprises: means, recorded on the recording medium, for extracting, from the structured document, structural elements having classification identifiers corresponding to the user classifications; and means, recorded on the recording medium, for writing the extracted structural elements into a session structured document in the session document. 36. The computer program product of claim 22 further comprising means, recorded on the recording medium, for filtering the presentation grammar, in dependence upon the extracted structural elements, into a session grammar in the session document. 37. The computer program product of claim 21 further comprising means, recorded on the recording medium, for creating a presentation document, including: means, recorded on the recording medium, for creating, in dependence upon an original document, a structured document comprising one or more structural elements; means, recorded on the recording medium, for classifying a structural element of the structured document according to a presentation attribute; and means, recorded on the recording medium, for creating a presentation grammar for the structured document, wherein the presentation grammar for the structured document includes grammar elements each of which includes an identifier for at least one structural element of the structured document. 38. The computer program product of claim 24 wherein means, recorded on the recording medium, for classifying a structural element comprises: means, recorded on the recording medium, for identifying a presentation attribute for the structural element; means, recorded on the recording medium, for identifying a classification identifier in dependence upon the presentation attribute; and means, recorded on the recording medium, for inserting the classification identifier in association with the structural element in the structured document. 39. The computer program product of claim 24 wherein means, recorded on the recording medium, for creating a presentation grammar for the structured document comprises: means, recorded on the recording medium, for identifying the content type of the original document; means, recorded on the recording medium, for selecting, in dependence upon the content type, a full presentation grammar from among a multiplicity of full presentation grammars; and means, recorded on the recording medium, for filtering the full presentation grammar into a presentation grammar for the structured document in dependence upon the structural elements of the structured document. | BACKGROUND OF THE INVENTION 1. Field of the Invention The field of the invention is data processing, or, more specifically, methods, systems, and products for differential dynamic content delivery. 2. Description Of Related Art Multimedia presentations through conferencing systems are becoming more common, but they are inflexible because all conference participants must be presented with exactly the same content. For any particular presentation, however, there is typically a wide variety of participant interest, company, group, or department membership, technical knowledge, security authorization, and so on, across almost any dimension in which participants may vary. Targeting content for such a heterogeneous set of users is typically a manual process today in which presenters create wholly separate presentations for each audience, and the content of each such presentation is reduced to the lowest common denominator of any particular audience. There is a substantial need for improved multimedia presentation systems. SUMMARY OF THE INVENTION Methods, systems, and products are disclosed that operate generally to support improved multimedia presentations by creating a presentation document that includes a content-specific presentation grammar and a structured document. The structured document typically has structural elements such as pages, paragraphs, cells, titles, and the like marked with structural identifiers. A content-specific presentation grammar ties presentation actions to the document structure through these structural element identifiers. A presentation actions directs the presentation of a document such as by moving the presentation to the next page of the document, the previous paragraph of the document and so on. A presentation grammar empowers a presenter to invoke the presentation actions using speech. In typical embodiments, users are assigned classifications describing any attributes of a user, company name, department name, age, gender, technical knowledge, educational level, subject matters of personal interest, security authorization, and so on. Contents of structural elements from structured documents are then filtered for presentation to individual users in a multi-media, multi-user presentation according to the individual attributes of the participants. In a presentation regarding marketing of a deep space vehicle for a Mars mission, for example, graphic images and paragraphs of text may be developed in many versions, inserted into the same presentation document with each version classified according to technical level, security level, and so on, so that a member of the marketing department viewing the same paragraph at the same time in the same presentation as a member of the research department will in fact be shown a different version of the paragraph. A graphic diagram of a subsystem presented to the marketer will be a simpler version than the one shown at the same time to the researcher. More particularly, methods, systems, and computer program products are disclosed for differential dynamic content delivery. Typical embodiments include providing a session document for a presentation, wherein the session document includes a session grammar and a session structured document; receiving a prerecorded presentation control instruction; selecting from the session structured document a classified structural element in dependence upon the prerecorded presentation control instruction and in dependence upon user classifications of a user participant in the presentation; and presenting the selected structural element to the user. In typical embodiments, the prerecorded presentation control instruction has an associated time stamp. Typical embodiments also include creating a prerecorded presentation session, including repeatedly: recording a presentation control instruction; and recording a time stamp in association with the presentation control instruction. Many embodiments also include creating the presentation control instruction, including: receiving from a user participating in the presentation a key phrase and optional parameters for invoking a presentation action; and parsing the key phrase and parameters against a voice response grammar into a presentation control instruction. In some embodiments, the prerecorded presentation control instruction includes a presentation action identifier and optional parameters and selecting a classified structural element includes selecting a classified structural element in dependence upon the presentation action identifier and the parameters. In typical embodiments, selecting a classified structural element includes selecting a classified structural element having an associated classification identifier that corresponds to the user classification. In many embodiments, presenting the selected structural element to the user includes selecting a data communications protocol for the presentation; inserting the selected structural element in a data structure appropriate to the data communications protocol; and transmitting the data structure to the user according to the data communications protocol. Many embodiments also include creating a session document from a presentation document, including identifying a presentation document for a presentation, the presentation document including a presentation grammar and a structured document having structural elements classified with classification identifiers; identifying a user participant for the presentation, the user having a user profile comprising user classifications; and filtering the structured document in dependence upon the user classifications and the classification identifiers. In typical embodiments, filtering the structured document includes extracting, from the structured document, structural elements having classification identifiers corresponding to the user classifications and writing the extracted structural elements into a session structured document in the session document. Some embodiments also include filtering the presentation grammar, in dependence upon the extracted structural elements, into a session grammar in the session document. Many embodiments of the present invention include creating a presentation document, including creating, in dependence upon an original document, a structured document comprising one or more structural elements; classifying a structural element of the structured document according to a presentation attribute; and creating a presentation grammar for the structured document, wherein the presentation grammar for the structured document includes grammar elements each of which includes an identifier for at least one structural element of the structured document. In many embodiments, classifying a structural element includes identifying a presentation attribute for the structural element identifying a classification identifier in dependence upon the presentation attribute and inserting the classification identifier in association with the structural element in the structured document. In some embodiments, creating a presentation grammar for the structured document includes identifying the content type of the original document; selecting, in dependence upon the content type, a full presentation grammar from among a multiplicity of full presentation grammars; and filtering the full presentation grammar into a presentation grammar for the structured document in dependence upon the structural elements of the structured document. The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular descriptions of exemplary embodiments of the invention as illustrated in the accompanying drawings wherein like reference numbers generally represent like parts of exemplary embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 sets forth a block diagram of an exemplary system architecture in which may be implemented various exemplary embodiments of the present invention. FIG. 2 sets forth class diagrams for exemplary object oriented classes useful in implementing methods and systems for creating presentation documents according to various exemplary embodiments of the present invention. FIG. 3 sets forth a data flow diagram illustrating a method for creating a presentation document. FIG. 4 sets forth a data flow diagram illustrating an exemplary method of creating a presentation grammar. FIG. 5 sets forth an exemplary data structure in which a full grammar may be implemented according to embodiments of the present invention. FIG. 6 is a data flow diagram illustrating a further method for creating a presentation document. FIG. 7 is a data flow diagram illustrating an exemplary method for classifying a structural element. FIG. 8 sets forth a data flow diagram illustrating an exemplary method for classifying a structural element in a structured document. FIG. 9 sets forth a data flow diagram illustrating a further exemplary method for classifying a structural element in a structured document. FIG. 10 sets forth a data flow diagram illustrating another exemplary method for classifying a structural element in a structured document. FIG. 11 sets forth a data flow diagram illustrating a further exemplary method for classifying a structural element in a structured document. FIG. 12 sets forth a data flow diagram illustrating an exemplary method for creating a voice response grammar in a voice response server. FIG. 13 sets forth a data flow diagram illustrating an exemplary method for creating a voice response grammar in a voice response server. FIG. 14 is a data flow diagram illustrating an alternative exemplary method for creating a voice response grammar in a voice response server. FIG. 15 is a data flow diagram illustrating another alternative exemplary method for creating a voice response grammar in a voice response server. FIG. 16 sets forth a data flow diagram illustrating an exemplary method for creating a session document from a presentation document. FIG. 17 sets forth a data flow diagram illustrating an exemplary method for amending a session document during a presentation. FIG. 18 sets forth a data flow diagram illustrating an exemplary method for differential dynamic content delivery. FIG. 19 sets forth a data flow diagram illustrating another exemplary method for differential dynamic content delivery with prerecorded presentation control instructions. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS Introduction The present invention is described to a large extent in this specification in terms of methods for differential dynamic content delivery. Persons skilled in the art, however, will recognize that any computer system that includes suitable programming means for operating in accordance with the disclosed methods also falls well within the scope of the present invention. Suitable programming means include any means for directing a computer system to execute the steps of the method of the invention, including for example, systems comprised of processing units and arithmetic-logic circuits coupled to computer memory, which systems have the capability of storing in computer memory, which computer memory includes electronic circuits configured to store data and program instructions, programmed steps of the method of the invention for execution by a processing unit. The invention also may be embodied in a computer program product, such as a diskette or other recording medium, for use with any suitable data processing system. Embodiments of a computer program product may be implemented by use of any recording medium for machine-readable information, including magnetic media, optical media, or other suitable media. Persons skilled in the art will immediately recognize that any computer system having suitable programming means will be capable of executing the steps of the method of the invention as embodied in a program product. Persons skilled in the art will recognize immediately that, although most of the exemplary embodiments described in this specification are oriented to software installed and executing on computer hardware, nevertheless, alternative embodiments implemented as firmware or as hardware are well within the scope of the present invention. Creating a Presentation Document Methods, systems, and products are now described for creating a presentation document with reference to the accompanying drawings, beginning with FIG. 1. FIG. 1 sets forth a block diagram of an exemplary system architecture in which may be implemented various exemplary embodiments of the present invention. The system of FIG. 1 include a content server (106) having stored content (108) of original documents from which presentation documents are created. Agent (110) includes software modules for creating presentation grammars for presentation documents according to content type (114) and for classifying presentation document content according to presentation attributes (116). Presentation attributes are generic selection criteria for displaying appropriate structural elements of original documents to users. Examples of presentation attributes include users' company names, department names, security levels, technical levels, and so on. User profiles (126) include user classification information typically used to filter presentation media according to presentation attributes. Content server (106) includes storage for presentation documents (314) each of which is composed of a presentation grammar (120) and a structured document (122). A presentation grammar is a data structure that includes a set of key phrases used to identify presentation action identifiers and optional parameters for use in formulating presentation control instructions relevant to structural elements of a content type. In typical embodiments, presentation control instructions are represented by and formulated from presentation action identifiers (reference 518 on FIG. 5). Key phrases are spoken by users and presented as speech input to voice response server (104) where they are parsed and used to select a presentation action identifier (518 on FIG. 5) from a VRS grammar (105). VRS grammar (105) is formed dynamically from presentation grammars (120) in use in a presentation session (128). In some embodiments, VRS grammar (105) is formed dynamically from user grammars from user profiles (126). Presentation Session Control Language (“PSCL”) stream (132) represents a stream of presentation control instructions composed of presentation action identifiers (518 on FIG. 5) and optional presentation control parameters (520 on FIG. 5) from VRS (104) to presentation server (102) which is programmed to present (134) structured multimedia content (136) from structured documents (122) to users (124) in accordance with such presentation control instructions (132). FIG. 2 sets forth class diagrams for exemplary object oriented classes useful in implementing methods and systems for creating presentation documents according to various exemplary embodiments of the present invention. FIG. 2 includes a presentation document class (314) that includes a reference to a presentation grammar (120), a reference to a structured document (122), and a network location (202) of an original document from which the presentation document was created. In the example of FIG. 2, the network location (202) of the original document is expressed as a Uniform Resource Identifier or “URI.” FIG. 2 includes a profile class (126) whose objects represent presentation users. The profile class (126) includes a user name (204), a password (206), and a reference to a user grammar (208). A user grammar is a data structure that includes a set of key phrases that are used to select presentation action identifiers specific to a user for use in formulating presentation control instructions. For a presentation control instruction that instructs a presentation session to carry out the presentation action ‘page down,’ for example, an individual user may chose to associate with that presentation control instruction the key phrase “rock and roll” or “boogie on down” or any other key phrase favored by a user as will occur to those of skill in the art. Although these particular examples are somewhat fanciful, in fact, user grammars serve a useful purpose by providing key phrases for presentation control instructions that distinguish normal speech. In a discussion of a word processing document, for example, references to pages and paragraphs may abound, and using a distinctive phrase to invoke presentation control instructions on pages and paragraphs reduces the risk of confusion on the part of a voice response server and a presentation session. The profile class (126) also includes a string array storing user classifications (210). Examples of user classifications (210) include any supported data codes describing users, including, for example “company=IBM,” “department=marketing,” “technical level=3,” “security level=2,” and others as will occur to those of skill in the art. FIG. 2 includes a presentation session class (128) whose objects represent presentation sessions. A presentation session represents an aggregation of presentation documents for presentation usually at a set date and time, for a defined set of users including a presenter in charge. The presentation session class (128) includes a presentation identifier code (212), a presenter identification (214), a list of participants (216). The presentation session class (128) also includes a schedule date and time (218) when a presentation is to be presented, a URI array identifying presentation documents (220) requested by a presenter for a presentation session, a URI array identifying presentation documents that have been filtered according to presentation attributes or user classifications (220). The presentation session class (128) also includes a member method named mergeGrammars( ) (224) that is programmed to read presentation grammars from presentation documents and store them in a VRS grammar on a voice response server for use in parsing key phrases spoken by a presenter and other users into presentation control instructions. Agent (110) includes software modules for structuring a presentation document according to content type (114) and for classifying presentation document content according to presentation attributes (116). FIG. 2 includes an exemplary agent class (110) whose objects are used in content servers to create presentation documents. Agent class (110) includes an array of references to content type plug-ins (114) that are used to create presentation grammars for presentation documents according to content type. FIG. 2 also shows a content type plug-in class (114) with a member method named createPresentationGrammar( ) (232) which in this example is programmed to create presentation grammars for presentation documents according to content type. Agent class (110) also includes an array of references to classification plug-ins (116) that are used to classify presentation document content according to presentation attributes (116). FIG. 2 also shows a classification plug-in class (116) with a member method named classifyDocument( ) (234) which in this example is programmed to classify presentation document content according to presentation attributes. Agent class (110) also includes a member method named createStructuedDocument( ) (232) which is programmed to convert an original document into a structured document by inserting structural element identifiers. Examples of structural element identifiers include <page>, <paragraph>, <row>, <column>, <cell>, <slide>, <jpeg>, <title>, <heading>, <subheading>, and so on, as will occur to those of skill in the art. These examples of structural elements identifiers are expressed as markup tags such as would be used, for example, in a markup language such as HTML (“HyperText Markup Language”) or XML (“eXtensible Markup Language”), although this is not a limitation of the invention. In fact, it is well within the scope of the present invention to implement structural element identifiers with binary codes, Unicode identifiers, or by use of other structure identifiers as will occur to those of skill in the art. FIG. 3 sets forth a data flow diagram illustrating a method for creating a presentation document (314) that includes creating (304), in dependence upon an original document (302), a structured document (306) comprising one or more structural elements (402). In the method of FIG. 3, creating (304) a structured document (306) is carried out by inserting (320) in the structured document (306) structural element identifiers (322) for the structural elements (402). An alternative method of creating a structured document, also shown in FIG. 3, is carried out by converting (326) existing structural element identifiers (324) from the original document (302) to structural element identifiers (322) for the structural elements (402) of the structured document (306). The method of FIG. 3 also includes creating (310) a presentation grammar (312) for the structured document (306). In the example of FIG. 3, the presentation grammar (312) for the structured document (306) includes grammar elements (316) each of which includes a structural element identifier (318) for at least one structural element (402) of the structured document (306). FIG. 4 sets forth a data flow diagram illustrating an exemplary method of creating a presentation grammar (312) for a structured document (314) that includes identifying (404) the content type (410) of the original document (302). Identifying the content type may be carried out, for example, by identifying the content type in dependence upon a filename extension (303) in the filename of an original document. Examples of filename extension identifying content type include ‘pdf’ for Adobe's Portable Document Format, ‘xls’ for a Microsoft Excel™ spreadsheet, ‘doc’ for a word processing document, ‘xml’ for an XML document, and so on, as will occur to those of skill in the art. Alternatively, identifying the content type may be carried out by identifying the content type in dependence upon document header elements in an original document (302). The following is an example of an HTML header identifying an original document having content type HTML version 4.01: <!DOCTYPE HTML PUBLIC “-//W3C//DTD HTML 4.01//EN” “http://www.w3.org/TR/html4/strict.dtd”> The method of FIG. 4 includes selecting (406), in dependence upon the content type (410), a full presentation grammar (308) from among a multiplicity of full presentation grammars (412). A full presentation grammar may be implemented, for example, as shown in FIG. 5. A multiplicity of full presentation grammars may be implemented in a data structure similar to the one shown in FIG. 5 by adding a content type column. FIG. 5 sets forth an exemplary data structure (308) in which a full grammar may be implemented according to embodiments of the present invention. The full grammar of FIG. 5 includes several grammar elements (502-514) for a content type. In this example, the content type is taken as a word processing document having structural elements that include pages, paragraphs, bullets, titles, subtitles, and so on, and the data structure includes a column for an identifier (318) of a structural element, a column for a key phrase (516) for formulating a presentation control instruction for invoking a presentation action, and a column for a presentation action identifier (518) representing a presentation action. The exemplary data structure of FIG. 5 also includes a column for a data indication whether a presentation control instruction requires a parameter. The exemplary grammar entries for presentation action identifiers PgDn (502), PgUp (504), nextParagraph (508), and prevBullet (512) have parameter (520) values of ‘null,’ signifying that a voice response server parsing their key phrases into presentation control instructions is not to parse a parameter for a presentation control instruction. The exemplary grammar entries for presentation action identifiers goToPage (506), nextHeading (510), and goToSubtitle (514), however, have parameter (520) values of ‘integer’ and ‘string,’ signifying that a voice response server parsing their key phrases into presentation control instructions is to seek to parse for each of them respectively an integer parameter, a string parameter, and a string parameter. The method of FIG. 4 includes filtering (408) the full presentation grammar (308) into a presentation grammar (312) for the structured document (306) in dependence upon the structural elements (402) of the structured document (306). Filtering (408) the full presentation grammar (308) may be carried out by writing (414) from the full presentation grammar (308) to the presentation grammar (312) for the structured document (306) each grammar element (316) having a structural element identifier (318) of a structural element (402) that occurs in the structured document (306). Using the exemplary full grammar of FIG. 5, for example, to create a presentation grammar for a structured document having structural elements including pages, paragraphs, headings, and subtitles but no bullet points identified in it as structural elements, filtering (408) the full presentation grammar (308) by writing (414) to the presentation grammar (312) grammar elements (502-510) plus grammar element (514) but excluding grammar element (512). Methods of creating presentation documents are further explained with an exemplary use case. Consider the following example of a structured document: <document> <page id=“1”> <p id=“1”>a paragraph</p> <p id=“2”>another paragraph</p> <image id=“1”>a graphic image</image> </page> <page id=“2”> <p id=“3”>a paragraph</p> <p id=“4”>another paragraph</p> <image id=“2”>another graphic image</image> </page> </document> And assume that this exemplary structured document is associated in a presentation document with the following presentation grammar: TABLE 1 Presentation Grammar Presentation Structural Action Element Key Phrase Identifier Identifier Parameter page down PgDn <page> null page up PgUp <page> null go to page goToPage <page> integer next paragraph nextParagraph <p> null go to paragraph goToParagraph <p> integer next image nextImage <image> null go to image goToImage <image> integer This example is discussed with reference to the exemplary system architecture of FIG. 1. In this example, then, when a presentation session (128) displays the first page of the structured document and a user (124) speaks the words “page down,” a voice response server (104), having this presentation grammar as part of its VRS grammar (105), parses the speech into a presentation control instruction having a presentation control identifier named “PgDn” and communicates the presentation control instruction through a presentation interface (132) to the presentation session in presentation server (102) which then displays the next page, in this example, page 2 of the example structured document. Similarly, when the first page of the structured document is on display, a user's speaking the words “go to paragraph 4” results in the presentation session's changing the display to show paragraph 4 on the second page of the document. And, when the first page is on display for the users participating in the presentation and a user speaks the words “next image,” the presentation session changes the display to show image 2 on the second page of the document. Classifying Structure Elements in a Presentation Document FIG. 6 is a data flow diagram illustrating a further method for creating a presentation document (314). The method of FIG. 6 includes creating (304), in dependence upon an original document (302), a structured document (306) comprising one or more structural elements (402), as explained in detail above. The method of FIG. 6 also includes classifying (330) a structural element (402) of the structured document (306) according to a presentation attribute (352). FIG. 7 is a data flow diagram illustrating an exemplary method for classifying a structural element that includes identifying (702) a presentation attribute (352) for the structural element (402); identifying (704) a classification identifier (708) in dependence upon the presentation attribute (352); and inserting (706) the classification identifier (708) in association with the structural element (402) in the structured document (306). The method of FIG. 6 also includes creating (310) a presentation grammar (312) for the structured document (306), wherein the presentation grammar (312) for the structured document (306) includes grammar elements (316) each of which includes an identifier (318) for at least one structural element (402) of the structured document (306). FIG. 8 sets forth a data flow diagram illustrating an exemplary method for classifying a structural element in a structured document in which identifying (702) a presentation attribute (352) for the structural element (402) includes selecting (710) a presentation attribute (352) from a list (712) of supported presentation attributes (352). The presentation attribute list (712) of FIG. 8 includes two columns, one column for presentation attributes (352) and another column for associated classification identifiers (708). In the method of FIG. 8, identifying (704) a classification identifier (708) is carried out by identifying a classification identifier (708) associated with the presentation attribute (352) on the list (712). In the method of FIG. 8, inserting (706) the classification identifier (708) includes manually editing (712) the structured document (306) to insert classification identifiers in appropriate locations to classify structural elements in a structured document. For example, a paragraph to be viewed only by members of the marketing department may be classified by tagging the paragraph with <mkt></mkt>. FIG. 9 sets forth a data flow diagram illustrating a further exemplary method for classifying a structural element in a structured document in which identifying (702) a presentation attribute (352) for the structural element (402) includes selecting (710) a presentation attribute (352) from a list (712) of supported presentation attributes (352), the presentation attribute (352) having an associated classification identifier (708). In the method of FIG. 9, identifying (704) a classification identifier (708) includes inserting (716) the classification identifier (708) in a data structure (717) in association with a structural element identifier (322) for the structural element (402). In the method of FIG. 9, inserting (706) the classification identifier (708) in the structured document (306) includes reading (714) the classification identifier (708) from the data structure (717) in dependence upon the structural element identifier (322). FIG. 10 sets forth a data flow diagram illustrating another exemplary method for classifying a structural element in a structured document that includes providing a list (712) of supported presentation attributes (352) including at least one keyword (802) and at least one indication of structural insertion scope (804) for each presentation attribute (352). In the method of FIG. 10, identifying (702) a presentation attribute (352) for the structural element (402) includes selecting (710) a presentation attribute (352) from the list (712) in dependence upon a keyword (806) from the structured document (306). In the method of FIG. 10, identifying (704) a classification identifier (708) is carried out by identifying a classification identifier (708) associated with the presentation attribute (352) on the list (712). In the method of FIG. 10, inserting (706) the classification identifier (708) is carried out by inserting the classification identifier (708) in the structured document (306) according to a structural insertion scope (804) for the selected presentation attribute (352). FIG. 11 sets forth a data flow diagram illustrating a further exemplary method for classifying a structural element in a structured document that includes providing a list (712) of supported presentation attributes (352) including at least one data pattern (810) and at least one indication of structural insertion scope (804) for each presentation attribute (352). In the method of FIG. 11, identifying (702) a presentation attribute (352) for the structural element (402) includes selecting (814) a presentation attribute (352) from the list (712) in dependence upon a data pattern (812) from the structured document (306). In the method of FIG. 11, identifying (704) a classification identifier (708) is carried out by identifying a classification identifier (708) associated with the presentation attribute (352) on the list (712). In the method of FIG. 11, inserting (706) the classification identifier (708) is carried out by inserting the classification identifier (708) in the structured document (306) according to a structural insertion scope (804) for the selected presentation attribute (352). Methods of creating presentation documents are further explained with an exemplary use case. Consider the following example of a structured document: <document> <page id=“1”> <p id=“1”> a paragraph on an introductory subject </p> </page> <page id=“2”> <p id=“2”> a paragraph on a particular subject </p> <tech level=“2”> <p id=“2”> a more technical paragraph on the same subject </p> </tech> <security level=“2”> <p id=“2”> a more secret paragraph on the same subject </p> </security> <dept id=“marketing”> <p id=“2”> a paragraph on the same subject with added detail regarding marketing </p> </dept> <company id=“IBM”> <p id=“2”> a paragraph on the same subject with added detail pertinent to a user's company </p> </company> <p id=“3”> a paragraph on a further subject </p> ... ... ... </page> <page id=“3”> ... ... ... </page> ... ... ... </document> This example is discussed with reference to the exemplary system architecture of FIG. 1, assuming that this exemplary structured document is associated in a presentation document with a presentation grammar that includes presentation action identifiers for paragraphs and pages uploaded to a VRS grammar (105) in a voice response server (104). In this example, then, when a presentation session (128) is displaying the first page of the structured document and a user (124) speaks the words “next page,” a voice response server (104) parses the speech into a presentation control instruction with a presentation action identifier named “PgDn” and communicates the presentation control instruction through a presentation interface (132) to the presentation session which then displays the next page, in this example, page 2 of the example structured document. Assume that there are five users (124) registered as participants with the presentation session (128), and note that there are five different versions of paragraph 2 on page two of the structured document. In this example, a first version of paragraph 2 bears a structural identifier <p></p> identifying it as a paragraph, but this first version of paragraph 2 bears no classification identifier. In this example, presentation session (128) is programmed to display this unclassified version of paragraph 2 to users having either the lowest technical classifications, the lowest security classifications, or no particular technical or security classifications at all. Moreover, in an example, where there were only one version of paragraph 2, all users would be presented with that one version. In this example, a second version of paragraph 2 is classified with a classification identifier <tech level=“2”>. In this example, presentation session (128) is programmed to display this second version of paragraph 2 to users having user classification indicating technical level 2. That is, when a user having technical level 2 in the user's profile classifications (210 on FIG. 2) is registered with the presentation session, upon being directed to display paragraph 2, rather than displaying an unclassified version of paragraph 2, the presentation session displays the second version of paragraph 2 classified <tech level=“2”> to such a user. Similarly, a user having a user profile classification representing a heightened security authorization, security level 2, is shown the version of paragraph 2 classified by the classification identifier <security level=“2”>. A user having a user profile classification identifying the user as a member of the marketing department is shown the version of paragraph 2 classified by the classification identifier <dept id=“marketing”>. A user having a user profile classification identifying the user as an employee of IBM is shown the version of paragraph 2 classified by the classification identifier <company id=“IBM”>. For purposes of clarity of explanation, the structural elements in this example are shown with only one classification per element. Persons of skill in the art will recognize, however, that it is well within the scope of the present invention for a structural element of a structured document to be classified with any number of classification identifiers. Creating a Voice Response Grammar From a Presentation Grammar FIG. 12 sets forth a data flow diagram illustrating a method for creating a voice response grammar in a voice response server including identifying (354) presentation documents (118) for a presentation. In the method of FIG. 4, each presentation document has a presentation grammar (120), and the method includes storing (358) each presentation grammar (120) in a voice response grammar (105) on a voice response server (104). Presentation grammars and voice response grammars may be structured like the full grammars illustrated in FIG. 5 with grammar elements (502-514) for a content type (410). In the exemplary grammar structure of FIG. 5, the content type is taken as a word processing document having structural elements that include pages, paragraphs, bullets, titles, subtitles, and so on, and the data structure includes a column for an identifier (318) of a structural element, a column for a key phrase (516) for formulating a presentation control instruction to invoke a presentation action, and a column for a presentation action identifier (518) representing a presentation action. In the method of FIG. 12, identifying (354) presentation documents (118) for a presentation includes creating (360) a data structure (128) representing a presentation and listing (362) at least one presentation document (118) in the data structure (128) representing a presentation. A data structure representing a presentation may be implemented as an instance of a presentation session class as shown at reference (128) on FIG. 2. In the method of FIG. 12, listing (362) the at least one presentation document (118) includes storing (366) a location (364) of the presentation document (118) in the data structure (128) representing a presentation. In the exemplary structure of FIG. 2, storing a location of a presentation document may be implemented by storing presentation document locations in the form of URIs in an array of URIs (220). In the method of FIG. 12, storing (358) each presentation grammar (120) includes retrieving (368) a presentation grammar (120) of the presentation document (118) in dependence upon the location (364) of the presentation document (118). In one exemplary embodiment of the method of FIG. 12, the presentation document (118) is implemented as a file in a file system on a content server (106) and the file has a location (364) identified by a pathname. In such an embodiment, storing (366) a location (364) of the presentation document (118) in the data structure (128) representing a presentation includes storing the pathname and a network location of the content server. An example of storing a pathname and a network location is storing a URI for the document in a URI array such as that illustrated at reference (220) on FIG. 2. Such a URI may have the form: http://www.someContentServer.com/presentationDocuments/myDoc.doc where www.someContentServer.com is a domain name for a web server that maps to a network address such as an Internet Protocol address, for example, of a computer where a web server is located. A ‘web server’ is a server that supports data communications according the HyperText Transport Protocol (‘HTTP’). The portion of the URI after the domain name, “presentationDocuments/myDoc.doc,” is a pathname for a document on the computer on which the web server is located. In such an embodiment, retrieving (368) a presentation grammar includes retrieving the presentation document from the content server (106) in dependence upon the pathname and extracting the grammar from the presentation document. In an example where the presentation document is located according to a URI as described above and the content server is implemented with a web server, retrieving the presentation document from the content server may be carried out by parsing the URI into an HTTP GET message: GET/presentationDocuments/myDoc.doc HTTP/1.1 and transmitting the GET message to the content server at www.ibmContentServer.com. In this example, the content server returns the presentation document as URI encoded data in an HTTP RESPONSE message. In an example where the returned presentation document has this form: <presentationDocument> <presentationGrammar> <grammarElement> <contentType id=“WP”> <keyPhrase> page down </keyPhrase> <presentationAction id=“PgDn”> <structuralElementIdentifier id=“page”> </grammarElement > </presentationGrammar> <structuredDocument> <page id=“1”> <p id=“1”> a paragraph </p> <p id=“2”> another paragraph </p> </page> <page id=“2”> some text </page> </structuredDocument> </presentationDocument>, extracting the grammar from the presentation document may be carried out by extracting the portion of the presentation document identified by the tags: <presentationGrammar></presentationGrammar> In another exemplary embodiment of the method of FIG. 12, the presentation document (118) is implemented as an instance of an object oriented class on a content server (106). In this example, the presentation document has a presentation document name, and the presentation grammar comprises a member data element of the instance. In such an embodiment, storing (366) a location (364) of the presentation document (118) in the data structure (128) representing a presentation includes storing the presentation document name and a network location of the content server. An example of storing a pathname and a network location is storing a URI for the document in a URI array such as that illustrated at reference (220) on FIG. 2. Such a URI may have the form: http://www.ibmContentServer.com/servlets/ getPresentationGrammar?presDoc=myDoc.doc where www.someContentServer.com is a domain name for a web server. The portion of the URI after the domain name but before the question mark, “servlets/getPresentationGrammar,” is a pathname for server-side functionality for retrieving a presentation document. The server-side functionality could be a CGI (Common Gateway Interface (‘CGI’) script or other server-side functionality as will occur to those of skill in the art, but in this example the server-side functionality is taken as a Java servlet identified by its name, “getPresentationGrammar.” The remainder of the URI is query data encoded as a name-value pair identifying the name of a presentation document, “myDoc.doc,” from which a presentation grammar is to be extracted by the servlet. In such an exemplary embodiment, retrieving (368) a presentation grammar is carried out by requesting the presentation grammar (120) from the content server (106), including communicating the presentation document name as a request parameter; and receiving the presentation grammar (120) in response from the content server (106). In an example where the presentation document is located according to a URI as described above and the content server is implemented with a web server, requesting the presentation grammar (120) from the content server (106), including communicating the presentation document name as a request parameter, may be carried out by parsing the URI into an HTTP GET message: GET/servlets/getPresentationGrammar?presDoc=myDoc.doc HTTP/1.1 and transmitting the GET message to the content server at www.ibmContentServer.com. In another exemplary embodiment of the method of FIG. 12, the presentation document (118) includes a record in a table in a database on a content server (106). In this example, the presentation document has a presentation document identifier, and the presentation grammar comprises a field in the record. In such an embodiment, storing (366) a location (364) of the presentation document (118) in the data structure (128) representing a presentation includes storing the presentation document identifier and a network location of the content server. In a database table in which each record represents a presentation document, for example, the presentation document identifier may be implemented as a single field unique key such as a serial number for a record, as a presentation document name, or as any functional identifier as will occur to those of skill in the art. In the continuing discussion of this example, the presentation document identifier is taken as a presentation document name. An example of storing a presentation document identifier and a network location is storing a URI for the document in a URI array such as that illustrated at reference (220) on FIG. 2. Such a URI may have the form: http://www.ibmContentServer.com/cgi-bin/ getPresentationGrammar?presDoc=myDoc.doc where www.someContentServer.com is a domain name for a web server. The portion of the URI after the domain name but before the question mark, “/cgi-bin/getPresentationGrammar,” is a pathname for server-side functionality for retrieving a presentation document. The server-side functionality could be a Java servlet or other server-side functionality as will occur to those of skill in the art, but in this example the server-side functionality is taken as a CGI script named “getPresentationGrammar.” The remainder of the URI is query data encoded as a name-value pair identifying the name of a presentation document, “myDoc.doc,” from which a presentation grammar is to be extracted by the CGI script. In such an exemplary embodiment, retrieving (368) a presentation grammar is carried out by requesting the presentation grammar (120) from the content server (106), including communicating the presentation document name as a request parameter; and receiving the presentation grammar (120) in response from the content server (106). In an example where the presentation document is located according to a URI as described above and the content server is implemented with a web server, requesting the presentation grammar (120) from the content server (106), including communicating the presentation document name as a request parameter, may be carried out by parsing the URI into an HTTP GET message: GET/cgi-bin/getPresentationGrammar?presDoc=myDoc.doc HTTP/1.1 and transmitting the GET message to the content server at www.ibmContentServer.com. Creating a Voice Response Grammar From a User Grammar FIG. 13 sets forth a data flow diagram illustrating a method for creating a voice response grammar in a voice response server including identifying (372) a user (374) for a presentation where the user has a user grammar (208) and the user grammar includes one or more user grammar elements (378). The method of FIG. 13 also includes storing (376) a multiplicity of user grammar elements (378) for the user in a voice response grammar (105) on a voice response server (104). A user grammar is a data structure that includes a set of key phrases specific to a user that are used to formulate presentation control instructions for invoking presentation actions on presentation servers. For a presentation control instruction that invokes a presentation action instructing a presentation session to ‘page down,’ for example, an individual user may chose to associate with that presentation control instruction the key phrase “rock and roll” or “boogie on down” or any other key phrase favored by a user as will occur to those of skill in the art. Although these particular example are somewhat fanciful, in fact, user grammars serve a useful purpose by providing key phrases for presentation actions that distinguish normal speech. User grammars and voice response grammars may be structured like the full grammars illustrated in FIG. 5 with grammar elements (502-514) for a content type (410). In the method of FIG. 13, identifying (372) a user for a presentation includes creating (360) a data structure (128) representing a presentation and listing (380) in the data structure (128, 374) at least one user identification (204). A data structure representing a presentation may be implemented as an instance of a presentation session class as shown at reference (128) on FIG. 2. In the method of FIG. 13, listing (380) in the data structure (128, 374) at least one user identification (204) includes creating a list of user names of the users that are registered with the presentation session. That is, a list of users currently participating in the presentation. In the example of FIG. 13, the user grammar (208) includes a multiplicity of user grammar elements (378) for a content type (370). In this example, each grammar element includes an identifier of a structural element, a key phrase for invoking a presentation action, and an action identifier representing the presentation action, as shown for example in the depiction of an exemplary full grammar at references (318), (518), and (516) on FIG. 5. The method of FIG. 13 includes identifying (382) presentation documents (118) for the presentation. In this example, each presentation document (118) having a content type (370), and selecting (384) user grammar elements (386) according to the content type (370) of the identified presentation documents (356). In the example of FIG. 13, selecting (384) user grammar elements (386) according to the content type (370) of the identified presentation documents (356) includes comparing the elements of the user grammar with each presentation document in the presentation session and extracting each element of the grammar having the same content type as a presentation document in the presentation session. In the method of FIG. 13, storing (376) a multiplicity of user grammar elements for the user in a voice response grammar on a voice response server is carried out by storing the selected user grammar elements (386) in the voice response grammar (105). FIG. 14 is a data flow diagram illustrating an alternative exemplary method for creating a voice response grammar in a voice response server. The method of FIG. 14 includes identifying (388) presentation documents (118) for the presentation. The presentation documents (118) in this example include structured documents (122) having structural element identifiers (322). In the example of FIG. 14, the identified presentation documents are included in a presentation document list (356) in the presentation session. The user grammar (208) in this example includes a multiplicity of user grammar elements (378), and the method includes selecting (390) user grammar elements (378) in dependence upon the structural element identifiers (322). In this example, selecting (390) user grammar elements (378) in dependence upon the structural element identifiers (322) is carried out by comparing the elements of the user grammar with each structured document of each presentation document in the presentation session and extracting each user grammar element having a structural element identifier for a structural element that occurs in a structured document of a presentation document in the presentation session. In the method of FIG. 14, storing (376) a multiplicity of user grammar elements for the user in a voice response grammar on a voice response server includes storing the selected user grammar elements (386) in the voice response grammar (105). FIG. 15 is a data flow diagram illustrating another alternative exemplary method for creating a voice response grammar in a voice response server. The method of FIG. 15 includes identifying (394) presentation documents (118) for the presentation. Each presentation document (118) has a presentation grammar (120) including presentation action identifiers (518). In the example of FIG. 15, the user grammar (208) includes a multiplicity of user grammar elements (378), and the method includes selecting (396) user grammar elements (378) in dependence upon the presentation action identifiers (518). In this example, selecting (396) user grammar elements (378) in dependence upon the presentation action identifiers (518) is carried out by comparing the elements of the user grammar with each presentation grammar of each presentation document of the presentation session and extracting from the user grammar each element having a presentation action identifier that occurs in a presentation grammar of the presentation document. In the method of FIG. 15, storing (376) a multiplicity of user grammar elements for the user in a voice response grammar on a voice response server includes storing the selected user grammar elements (386) in the voice response grammar (105). Creating a Session Document from a Presentation Document FIG. 16 sets forth a data flow diagram illustrating an exemplary method for creating a session document (266) from a presentation document (314). A session document is a repository for filtered content, presentation content that is filtered according to attributes of an audience for a presentation, an audience that presents a range of affiliations, technical abilities, security authorizations, and other attributes as will occur to those of skill in the art. The purpose of a session document is to provide a repository for reducing the volume of data for a presentation with respect to unfiltered presentation documents. A session document is a document derived from a presentation document targeted for the participants of a presentation. More particularly, a session document is a data structure that includes a session grammar derived from a presentation grammar in a presentation document and a session structured document derived from a structured document in a presentation document. The method of FIG. 16 includes identifying (250) a presentation document (314) for a presentation. The presentation document (314) includes a presentation grammar (312) and a structured document (306) having structural elements (402) classified with classification identifiers (708). Identifying (250) a presentation document (314) typically includes inserting in a list (220) a location for the presentation document (314). The location of a presentation document may be represented by a URI, and a list of locations identifying presentation documents may be implemented as an array of URIs as exemplified by the requested content list (220) in the exemplary presentation session class (128) on FIG. 2. The method of FIG. 16 includes identifying (252) a user participant (204) for the presentation. In the method of FIG. 16, the user has a user profile (126) that includes user classifications (210) each of which describes some attribute of a user, such as, for example, company affiliation, department membership, technical ability, security authorization level, and so on, for any attribute of a user as may occur to those of skill in the art. Identifying (252) a user (204) typically includes inserting in a list (374) a user identification (204) identifying a user in a presentation participant list (374). In the example of FIG. 16, a user identification is implemented as a user name (204) in a user profile (126). The method of FIG. 16 includes filtering (254) the structured document (306) in dependence upon the user classifications (210) and the classification identifiers (708). In the method of FIG. 16, filtering (254) the structured document (306) is carried out by extracting (259), from the structured document (306), structural elements (402) having classification identifiers (708) corresponding to the user classifications (210), and writing (260) the extracted structural elements (402) into a session structured document (256) in the session document (266). The method of FIG. 16 also includes filtering (262) the presentation grammar (312), in dependence upon the extracted structural elements (402), into a session grammar (258) in the session document (266). The method of FIG. 16 includes storing (264) the location of the session document (266) in a session document list (222). For further explanation, consider an example of creating a session document that begins with a presentation document having the following contents: <presentationDocument> <presentationGrammar> <grammarElement> <contentType id=“WP”> <keyPhrase>page down</keyPhrase> <presentationAction id=“PgDn”> <structuralElementIdentifier id=“page”> </grammarElement > <grammarElement> <contentType id=“WP”> <keyPhrase>next bullet</keyPhrase> <presentationAction id=“NextBullet”> <structuralElementIdentifier id=“bullet”> </grammarElement > </presentationGrammar> <structuredDocument> <page id=“1”> <p id=“1”>a paragraph on some subject</p> </page> <page id=“2”> <p id=“2”>a paragraph on a particular subject</p> <tech level=“2”> <p id=“2”>a more technical paragraph, same subject</p> </tech> <security level=“2”> <p id=“2”>a more secret paragraph, same subject</p> </security> <dept id=“marketing”> <p id=“2”>a paragraph, same subject, with added detail regarding marketing <bullet id =“1”>some bullet text</bullet> <bullet id =“1”>some other bullet text</bullet> <bullet id =“1”>still more bullet text</bullet> </p> </dept> <company id=“IBM”> <p id=“2”>a paragraph, same subject with added detail pertinent to a user's company</p> </company> <p id=“3”>a paragraph on some other subject</p> ... ... ... </page> </structuredDocument> </presentationDocument> In this example, an audience of users identified for a presentation include users having in their user profiles user classifications indicating technical level ‘2’ and membership in IBM. None of the registered users have security authorizations and none of them are from the marketing department. Filtering this exemplary presentation document, extracting structural elements with classification identifiers corresponding to the user classifications, writing those structural elements to a session document, and filtering the presentation grammar in dependence upon the extracted structural elements, results in the following exemplary session document: <sessionDocument> <sessionGrammar> <grammarElement> <contentType id=“WP”> <keyPhrase>page down</keyPhrase> <presentationAction id=“PgDn”> <structuralElementIdentifier id=“page”> </grammarElement > </sessionGrammar> <sessionStructuredDocument> <page id=“1”> <p id=“1”> a paragraph </p> <p id=“2”> another paragraph </p> </page> <page id=“2”> <p id=“2”>a paragraph on a particular subject</p> <tech level=“2”> <p id=“2”>a more technical paragraph, same subject</p> </tech> <company id=“IBM”> <p id=“2”>a paragraph, same subject with added detail pertinent to a user's company</p> </company> <p id=“3”>a paragraph on some other subject</p> ... ... ... </page> </sessionStructuredDocument> </sessionDocument> In the resulting session document, the structural element identified as page 2 now excludes versions for security level 2 and for marketing, because none of the users listed for the presentation are in the marketing department or have security authorizations of level 2. In addition, the session grammar excludes a grammar element for bullets because, in the session document above, the only structural element having bullets was the version of paragraph 2 for the marketing department. Excluding the bullets as structural elements in the session structured document means that there is no need to have grammar elements for them in the session grammar. Reducing the number of grammar elements in the session grammar reduces the number of grammar elements in the voice response grammar, thereby increasing the efficiency and accuracy of the voice response server and the overall presentation system. Amending a Session Document During a Presentation FIG. 17 sets forth a data flow diagram illustrating an exemplary method for amending a session document (266) during a presentation. The session document (266) includes a session structured document (256), and the method of FIG. 17 includes providing (268) user profiles (126) representing users capable of participating in presentations. In typical embodiments, user profiles for all the users capable of participating in presentations are stored in a database accessible to the presentation session. In the example of FIG. 17, each user profile (126) includes user classifications (210) for a user. The method of FIG. 17 also includes providing (270) a presentation document (314) that includes a structured document (306) having structural elements (402) classified with classification identifiers (708). In the example of FIG. 17, the locations of the presentation documents from which the session documents for a particular presentation were created are stored in a list such as the requested content list (220) of FIG. 17. The method of FIG. 17 includes identifying (274) a user profile event (272) for a user during the presentation. A user profile event is an event that results in adding a user classification to the set of user classifications for a presentation. The set of user classifications for a presentation is the set of all user classifications for all users that have been identified as users for a presentation. A user profile event may be represented as a data structure (272) that includes a user identification (205) for a particular user. A user profile event (272) may be generated by adding a user to the presentation, where the added user has a new user classification for the presentation. That is, one example of a user profile event (272) is adding to a presentation a user whose user classifications include at least one user classification having no corresponding classification identifier in any structural element in the session structured document. In such an example, at least one of the added user's user classifications is currently not part of any user profile of any of the other users identified for the presentation. A user profile event (272) also may be generated, for a further example, by changing a user classification (210) in a user profile (126) of a user who is participating in the presentation, where the changed user classification includes a new user classification for the presentation. That is, one example of a user profile event (272) is editing a user's profile during a presentation so that the user's user profile now includes a user classification having no corresponding classification identifier in any structural element in the session structured document. In such an example, the new user classification is currently not part of any user profile of any of the other users identified for the presentation. The method of FIG. 17 includes adding (276) to the session structured document (256) at least one structural element (402) from the presentation document (314), the added structural element (402) having a classification identifier (708) that corresponds to a user classification (210) of the user. In the examples just mentioned, regarding adding a new user to a presentation or a new user classification to a profile, adding (276) to the session structured document (256) a structural element (402) from the presentation document (314), the added structural element (402) having a classification identifier (708) that corresponds to a user classification (210) of the user, means that the new structural element is one that no other user identified for the presentation was entitled to view. Because adding a structural element may mean adding a structural element of a kind not otherwise represented in the session structured document, the method of FIG. 17 advantageously also includes adding (278) a grammar element (316) to the session grammar (258) in dependence upon the added structural element (402). For further explanation, consider the following example of amending a session document (266) during a presentation. In this example, a session document is used for a presentation having users whose user profiles include user classifications of technical level ‘2’ and membership in IBM: <sessionDocument> <sessionGrammar> <grammarElement> <contentType id=“WP”> <keyPhrase>page down</keyPhrase> <presentationAction id=“PgDn”> <structuralElementIdentifier id=“page”> </grammarElement > </sessionGrammar> <sessionStructuredDocument> <page id=“1”> <p id=“1”> a paragraph </p> <p id=“2”> another paragraph </p> </page> <page id=“2”> <p id=“2”>a paragraph on a particular subject</p> <tech level=“2”> <p id=“2”>a more technical paragraph, same subject</p> </tech> <company id=“IBM”> <p id=“2”>a paragraph, same subject with added detail pertinent to a user's company</p> </company> <p id=“3”>a paragraph on some other subject</p> ... ... ... </page> </sessionStructuredDocument> </sessionDocument> This session document in this example was created from the following presentation document: <presentationDocument> <presentationGrammar> <grammarElement> <contentType id=“WP”> <keyPhrase>page down</keyPhrase> <presentationAction id=“PgDn”> <structuralElementIdentifier id=“page”> </grammarElement > <grammarElement> <contentType id=“WP”> <keyPhrase>next bullet</keyPhrase> <presentationAction id=“NextBullet”> <structuralElementIdentifier id=“bullet”> </grammarElement > </presentationGrammar> <structuredDocument> <page id=“1”> <p id=“1”>a paragraph on some subject</p> </page> <page id=“2”> <p id=“2”>a paragraph on a particular subject</p> <tech level=“2”> <p id=“2”>a more technical paragraph, same subject</p> </tech> <security level=“2”> <p id=“2”>a more secret paragraph, same subject</p> </security> <dept id=“marketing”> <p id=“2”>a paragraph, same subject, with added detail regarding marketing <bullet id =“1”>some bullet text</bullet> <bullet id =“1”>some other bullet text</bullet> <bullet id =“1”>still more bullet text</bullet> </p> </dept> <company id=“IBM”> <p id=“2”>a paragraph, same subject with added detail pertinent to a user's company</p> </company> <p id=“3”>a paragraph on some other subject</p> ... ... ... </page> </structuredDocument> </presentationDocument> The session document in this example contains no structural elements classified for users from the marketing department. After beginning the presentation a user from the marketing department joins the presentation. The user's joining the presentation is represented by adding the user's user identification to a list of users identified for the presentation. Adding the user ID to the list identifies (274) a user profile event (272) which is represented by a data structure that includes the user's user identification (205). Amending the session document proceeds by adding (276) to a session structured document (256) one or more structural elements (402) from a structured document in the presentation document from which the session structured document was created. Adding (276) to the session structured document (256) at least one structural element (402) from the presentation document (314) is carried out by adding a structural element (402) having a classification identifier (708) that corresponds to a user classification (210) of the user. User classifications of the user are read from the user profiles (126) using the user identification (205) provided to the adding process (276) by the user profile event (272). In this example, adding a structural element to the session structured documents is carried out by adding the following paragraph from the structured document of the presentation document set forth above: <dept id=“marketing”> <p id=“2”>a paragraph, same subject, with added detail regarding marketing <bullet id =“1”>some bullet text</bullet> <bullet id =“1”>some other bullet text</bullet> <bullet id =“1”>still more bullet text</bullet> </p> </dept>, thereby creating the following amended session document: <sessionDocument> <sessionGrammar> <grammarElement> <contentType id=“WP”> <keyPhrase>page down</keyPhrase> <presentationAction id=“PgDn”> <structuralElementIdentifier id=“page”> </grammarElement > </sessionGrammar> <sessionStructuredDocument> <page id=“1”> <p id=“1”> a paragraph </p> <p id=“2”> another paragraph </p> </page> <page id=“2”> <p id=“2”>a paragraph on a particular subject</p> <tech level=“2”> <p id=“2”>a more technical paragraph, same subject</p> </tech> <company id=“IBM”> <p id=“2”>a paragraph, same subject with added detail pertinent to a user's company</p> </company> <dept id=“marketing”> <p id=“2”>a paragraph, same subject, with added detail regarding marketing <bullet id =“1”>some bullet text</bullet> <bullet id =“1”>some other bullet text</bullet> <bullet id =“1”>still more bullet text</bullet> </p> </dept> <p id=“3”>a paragraph on some other subject</p> ... ... ... </page> </sessionStructuredDocument> </sessionDocument> Amending the session document also includes adding to the session grammar of the session document a new grammar element from the presentation grammar. There 25 were no bullets in the session structured document before the exemplary user profile event and therefore no grammar elements supporting presentation control instructions for bullets. Adding the marketing paragraph also added bullets, so the method advantageously includes adding grammar elements supporting presentation control instructions for bullets: <grammarElement> <contentType id=“WP”> <keyPhrase>next bullet</keyPhrase> <presentationAction id=“NextBullet”> <structuralElementIdentifier id=“bullet”> </grammarElement >, thereby creating the following amended session document: <sessionDocument> <sessionGrammar> <grammarElement> <contentType id=“WP”> <keyPhrase>page down</keyPhrase> <presentationAction id=“PgDn”> <structuralElementIdentifier id=“page”> </grammarElement > <grammarElement> <contentType id=“WP”> <keyPhrase>next bullet</keyPhrase> <presentationAction id=“NextBullet”> <structuralElementIdentifier id=“bullet”> </grammarElement > </sessionGrammar> <sessionStructuredDocument> <page id=“1”> <p id=“1”> a paragraph </p> <p id=“2”> another paragraph </p> </page> <page id=“2”> <p id=“2”>a paragraph on a particular subject</p> <tech level=“2”> <p id=“2”>a more technical paragraph, same subject</p> </tech> <company id=“IBM”> <p id=“2”>a paragraph, same subject with added detail pertinent to a user's company</p> </company> <dept id=“marketing”> <p id=“2”>a paragraph, same subject, with added detail regarding marketing <bullet id =“1”>some bullet text</bullet> <bullet id =“1”>some other bullet text</bullet> <bullet id =“1”>still more bullet text</bullet> </p> </dept> <p id=“3”>a paragraph on some other subject</p> ... ... ... </page> </sessionStructuredDocument> </sessionDocument> Differential Dynamic Content Delivery FIG. 18 sets forth a data flow diagram illustrating an exemplary method for differential dynamic content delivery. Differential dynamic content delivery is delivery of the content of a presentation to user participants according to a wide variety of participant interest, company, group, or department membership, technical knowledge, security authorization, and so on, across almost any dimension in which participants may vary. Differential dynamic content delivery is accomplished generally in methods and systems according to embodiments of the present invention by use of structured, classified documents, presentation documents and session documents, each of which includes a grammar and a structured document as described below. Using such documents as a source of presentation content, differential dynamic content delivery is accomplished then by selecting from a structured document classified structural elements for delivery to particular user participants according to the classification identifiers in the document and user classifications from user profiles. FIG. 18 sets forth a data flow diagram illustrating an exemplary method for differential dynamic content delivery that includes providing (450) a session document (266) for a presentation. In the method of FIG. 18, the session document (266) includes a session grammar (258) and a session structured document (256), and providing (450) a session document (266) for a presentation is carried out by creating a session document from a presentation document as described in detail above in the discussion regarding FIG. 16. The method of FIG. 18 also includes creating (462) a presentation control instruction (460). A presentation control instruction is an instruction to a presentation server (102) to carry out a particular presentation action such as, for example, ‘display next page,’ ‘display next slide,’ ‘display paragraph 5,’ and so on. More particularly, in differential dynamic content delivery, presentation actions are carried out by presenting to a particular user a version of a particular structural element, such as a paragraph or a slide, according to user classifications such as company name, department name, security authorization, and so on. In the method of FIG. 18, an exemplary presentation control instruction (460) includes a presentation action identifier (518) and one or more optional parameters (520). In the method of FIG. 18, creating the presentation control instruction is carried out by receiving (464) from a user (124) participating in the presentation a key phrase (516) and optional parameters (520) for invoking a presentation action and parsing (466) the key phrase (516) and parameters (520) against a voice response grammar (105) into a presentation control instruction (460). In this example, receiving (464) a key phrase (516) is carried out by use of a Voice Over Internet Protocol (“VOIP”) link (130) that carries the speech of at least one user (124) from the user's client device to a voice response server (104). A VOIP link is a kind of computer hardware and software that uses an internet protocol network instead of a traditional telephone network as the transmission medium for speech. VOIP is sometimes referred to as ‘IP telephony’ or ‘Voice Over the Internet’ (“VOI”). Examples of user client devices include any computer equipment capable of converting input speech to digital data and transmitting it over the internet protocol to a voice response server, including handheld wireless devices, personal digital assistants, personal computers, laptop computers, and the like. The method of FIG. 18 also includes receiving (458) a presentation control instruction (460) in a presentation server and selecting (452) from a session structured document (256) a classified structural element (402) in dependence upon user classifications (210) of a user participant (124) in the presentation. In the method of FIG. 18, selecting (452) a classified structural element (402) is carried out by selecting a classified structural element (402) in dependence upon the presentation action identifier (518) and the parameters (520) from the presentation control instruction (460). In the method of FIG. 18, selecting (452) a classified structural element (402) also includes selecting a classified structural element having an associated classification identifier (708) that corresponds to the user classification (210). For further explanation, consider an example using the following exemplary session document: <sessionDocument> <sessionGrammar> <grammarElement> <contentType id=“WP”> <keyPhrase>page down</keyPhrase> <presentationAction id=“PgDn”> <structuralElementIdentifier id=“page”> </grammarElement > </sessionGrammar> <sessionStructuredDocument> <page id=“1”> <p id=“1”> a paragraph </p> <p id=“2”> another paragraph </p> </page> <page id=“2”> <p id=“2”>a paragraph on a particular subject</p> <tech level=“2”> <p id=“2”>a more technical paragraph, same subject</p> </tech> <company id=“IBM”> <p id=“2”>a paragraph, same subject with added detail pertinent to a user's company</p> </company> <p id=“3”>a paragraph on some other subject</p> ... ... ... </page> </sessionStructuredDocument> </sessionDocument> In this example, assume that a first user participant has in a user profile user classifications indicating that the user is an IBM employee and a second user has user classifications indicating that the user has technical ability level ‘2’. In this example, a presentation server having the above session document installed upon it receives (458) a presentation control instruction (460) to move to the display to the second page of the session structured document. The presentation server then selects (452) from the session structured document (256) for the first user the structural element identified as a version of page two and classified as: <company id=“IBM”> <p id=“2”>a paragraph, same subject with added detail pertinent to a user's company</p> </company> and for the second user the structural element identified as a version of page two and classified as: <tech level=“2”> <p id=“2”>a more technical paragraph, same subject</p> </tech> The method of FIG. 18 also includes presenting (454) the selected structural element (456) to the user (124). In the method of FIG. 18, presenting (454) the selected structural element (456) to the user may be carried out, for example, by selecting a data communications protocol for the presentation, inserting the selected structural element (without its classification identifiers) in a data structure appropriate to the data communications protocol, and transmitting the data structure to the user according to the data communications protocol. If, for example, the data communications protocol is selected as HTTP, a data structure appropriate to the data communications protocol is an HTML document in an HTTP RESPONSE message. In such an example, presenting (454) the selected structural element (456) to the user may be carried out, for the two exemplary versions of page two selected above, by the following HTTP RESPONSE messages: HTTP/1.1 200 OK Date: Content-Type: text/xml Content-Length: 128 <html><body><p id=“2”>a paragraph, same subject with added detail pertinent to a user's company</p> </body></html> and for the second user the structural element identified as a version of page two and classified as: HTTP/1.1 200 OK Date: Content-Type: text/xml Content-Length: 103 <html><body><p id=“2”>a more technical paragraph, same subject</p></body></html> respectively, the first sent to the client device of the first user and the second sent to the client device of the second user. Note that in both transmission, the classification identifiers are omitted, <company id=“IBM”> and <tech level=“2”> respectively. This example of presenting (454) a selected structural element (456) to a user (124) is expressed in terms of HTML and HTTP, a stateless, asynchronous protocol. Many embodiments will statefully hold open a data communications connection, such as a TCP/IP connection, between a presentation server and a user client device. A Stateful Java Enterprise Session Bean™ may be used, for example, to hold open a TCP/IP connection implemented with a Java socket object. Readers of skill in the art will recognize therefore that HTML and HTTP are used for explanation, not for limitation. In fact, any presentation application using any appropriate data communications protocol useful for multi-media presentations may be used to present structural elements to users according to embodiments of the present invention. Such application may be obtained off-the-shelf commercially or they may be specially developed for particular presentations or kinds of presentation. An example of such an application available commercially is Microsoft NetMeeting™. Examples of other data communications protocols useful with various embodiments of the present invention include the Session Initiation Protocol specified in the IETF's RFC 2543, the Real Time Streaming Protocol as specified in the IETF's RFC 2326, the Real Time Transport Protocol of RFC 1889, and the World Wide Web Consortium's VoiceXML protocol specified in the 2003 document entitled “Voice Extensible Markup Language (VoiceXML) Version 2.0”. Differential Dynamic Content Delivery with Prerecorded Presentation Control Instructions FIG. 19 sets forth a data flow diagram illustrating an exemplary method for differential dynamic content delivery with prerecorded presentation control instructions. FIG. 19 sets forth a data flow diagram illustrating an exemplary method for differential dynamic content delivery that includes providing (450) a session document (266) for a presentation. In the method of FIG. 19, the session document (266) includes a session grammar (258) and a session structured document (256), and providing (450) a session document (266) for a presentation is carried out by creating a session document from a presentation document as described in detail above in the discussion regarding FIG. 16. The method of FIG. 19 includes creating (484) a prerecorded presentation session (482), including repeatedly recording (478) a presentation control instruction (460); and recording (480) a time stamp (472) in association with the presentation control instruction (460). The prerecorded presentation session of FIG. 19 is a collection of recorded presentation control instructions associated with a collection of time stamps. As discussed above, a presentation control instruction (460) is an instruction to a presentation server (102) to carry out a particular presentation action such as, for example, ‘display next page,’ ‘display next slide,’ ‘display paragraph 5,’ and so on. Recording presentation control instructions with time stamps advantageously allows playback of a prerecorded presentation session. In the method of FIG. 19, recording a presentation control instruction (460) results in a prerecorded presentation control instruction (470). That is, a recorded presentation control instruction (460) is a prerecorded presentation control instruction (470). The method of FIG. 19 includes playback of a prerecorded presentation session. Playback of the prerecorded presentation session typically includes sending prerecorded presentation control instructions to a presentation server at time intervals dictated by time stamps associated with the prerecorded presentation control instructions. In the example of FIG. 19, the presentation control instruction recorder (468) uses a system clock (476) to time the playback of the prerecorded presentation session. The method of FIG. 19 includes receiving (458) a prerecorded presentation control instruction (470) having an associated time stamp (472) and selecting (452) from the session structured document (256) a classified structural element (402) in dependence upon the prerecorded presentation control instruction (470) and in dependence upon user classifications of a user participant in the presentation. In the method of FIG. 19, selecting (452) a classified structural element (402) is carried out by selecting a classified structural element (402) in dependence upon the presentation action identifier (518) and the parameters (520) from prerecorded presentation control instruction (470). In the method of FIG. 19, selecting (452) a classified structural element (402) also includes selecting a classified structural element having an associated classification identifier (708) that corresponds to the user classification (210). For further explanation, consider an example using the following exemplary session document: <sessionDocument> <sessionGrammar> <grammarElement> <contentType id=“WP”> <keyPhrase>page down</keyPhrase> <presentationAction id=“PgDn”> <structuralElementIdentifier id=“page”> </grammarElement > </sessionGrammar> <sessionStructuredDocument> <page id=“1”> <p id=“1”> a paragraph </p> <p id=“2”> another paragraph </p> </page> <page id=“2”> <p id=“3”>a paragraph on a particular subject</p> <tech level=“2”> <p id=“3”>a more technical paragraph, same subject</p> </tech> <company id=“IBM”> <p id=“3”>a paragraph, same subject with added detail pertinent to a user's company</p> </company> <p id=“4”>a paragraph on some other subject</p> ... ... ... </page> </sessionStructuredDocument> </sessionDocument> In this example, assume that a first user participant has in a user profile user classifications indicating that the user is an IBM employee and a second user has user classifications indicating that the user has technical ability level ‘2’. In this example, a presentation server receives prerecorded presentation control instructions (470) from playback of a presentation control instruction recorder (468). The presentation server (102) has the above session document installed upon it receives (458) a prerecorded presentation control instruction (470) to move to the display to the third paragraph of the session structured document. The presentation server then selects (452) from the session structured document (256) for the first user the structural element identified as a version of paragraph 3 and classified as: <company id=“IBM”> <p id=“3”>a paragraph, same subject with added detail pertinent to a user's company</p> </company> and for the second user the structural element identified as a version of page two and classified as: <tech level=“2”> <p id=“3”>a more technical paragraph, same subject</p> </tech> The method of FIG. 19 also includes presenting (454) the selected structural element (456) to the user (124). In the method of FIG. 19, presenting (454) the selected structural element (456) to the user may be carried out, for example, by selecting a data communications protocol for the presentation, inserting the selected structural element (without its classification identifiers) in a data structure appropriate to the data communications protocol, and transmitting the data structure to the user according to the data communications protocol. If, for example, the data communications protocol is selected as HTTP, a data structure appropriate to the data communications protocol is an HTML document in an HTTP RESPONSE message. In such an example, presenting (454) the selected structural element (456) to the user may be carried out, for the two exemplary versions of page two selected above, by the following HTTP RESPONSE messages: HTTP/1.1 200 OK Date: Content-Type: text/xml Content-Length: 128 <html><body><p id=“3”>a paragraph, same subject with added detail pertinent to a user's company</p> </body></html> and for the second user the structural element identified as a version of page two and classified as: HTTP/1.1 200 OK Date: Content-Type: text/xml Content-Length: 103 <html><body><p id=“3”>a more technical paragraph, same subject</p></body></html> respectively, the first sent to the client device of the first user and the second sent to the client device of the second user. Note that in both transmission, the classification identifiers are omitted, <company id=“IBM”> and <tech level=“2”> respectively. As noted, the method of FIG. 19 includes creating (484) a prerecorded presentation session (482) by recording (478) a presentation control instruction (460) as a prerecorded presentation control instruction (470) and recording (480) along with the prerecorded presentation control instruction a time stamp (472) indicating when during a presentation a particular prerecorded presentation control instruction is to be played back by, for example, sending (474) it along to a presentation server (102) for execution. One way for a user to record (478) a presentation control instruction is to simply type it into a table through a keyboard, a traditional kind of data entry in which a sequence of presentation control instruction become a kind of macro or software program for controlling playback of a presentation. FIG. 20 illustrates an additional exemplary method of recording presentation control instruction (460) to create prerecorded presentation control instructions (470). The method of FIG. 20 records (478) presentation control instructions (460) as they are created (462) from key phrases (516) spoken remotely by a user (124) and communicated to a voice response server through a VIOP connection (130). The key phrases may be spoken as part of a live presentation in which the presentation control instructions are received (458), used to select (452) classified structural elements which are then presented (454) to the users participating in a live presentation. Or the presentation control instructions (460) may be recorded (478) off-line, as it were, without simultaneous live reception (458), selection (452), and presentation (454) of selected structural elements (446) to users. More particularly, the method of FIG. 20 includes creating (462) a presentation control instruction (460). In the method of FIG. 20, an exemplary presentation control instruction (460) includes a presentation action identifier (518) and one or more optional parameters (520). In the method of FIG. 20, creating the presentation control instruction is carried out by receiving (464) from a user (124) participating in the presentation a key phrase (516) and optional parameters (520) for invoking a presentation action and parsing (466) the key phrase (516) and parameters (520) against a voice response grammar (105) into a presentation control instruction (460). In this example, receiving (464) a key phrase (516) is carried out by use of a Voice Over Internet Protocol (“VOIP”) link (130) that carries the speech of at least one user (124) from the user's client device to a voice response server (104). Examples of user client devices include any computer equipment capable of converting input speech to digital data and transmitting it over the internet protocol to a voice response server, including handheld wireless devices, personal digital assistants, personal computers, laptop computers, and the like. It will be understood from the foregoing description that modifications and changes may be made in various embodiments of the present invention without departing from its true spirit. The descriptions in this specification are for purposes of illustration only and are not to be construed in a limiting sense. The scope of the present invention is limited only by the language of the following claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The field of the invention is data processing, or, more specifically, methods, systems, and products for differential dynamic content delivery. 2. Description Of Related Art Multimedia presentations through conferencing systems are becoming more common, but they are inflexible because all conference participants must be presented with exactly the same content. For any particular presentation, however, there is typically a wide variety of participant interest, company, group, or department membership, technical knowledge, security authorization, and so on, across almost any dimension in which participants may vary. Targeting content for such a heterogeneous set of users is typically a manual process today in which presenters create wholly separate presentations for each audience, and the content of each such presentation is reduced to the lowest common denominator of any particular audience. There is a substantial need for improved multimedia presentation systems. | <SOH> SUMMARY OF THE INVENTION <EOH>Methods, systems, and products are disclosed that operate generally to support improved multimedia presentations by creating a presentation document that includes a content-specific presentation grammar and a structured document. The structured document typically has structural elements such as pages, paragraphs, cells, titles, and the like marked with structural identifiers. A content-specific presentation grammar ties presentation actions to the document structure through these structural element identifiers. A presentation actions directs the presentation of a document such as by moving the presentation to the next page of the document, the previous paragraph of the document and so on. A presentation grammar empowers a presenter to invoke the presentation actions using speech. In typical embodiments, users are assigned classifications describing any attributes of a user, company name, department name, age, gender, technical knowledge, educational level, subject matters of personal interest, security authorization, and so on. Contents of structural elements from structured documents are then filtered for presentation to individual users in a multi-media, multi-user presentation according to the individual attributes of the participants. In a presentation regarding marketing of a deep space vehicle for a Mars mission, for example, graphic images and paragraphs of text may be developed in many versions, inserted into the same presentation document with each version classified according to technical level, security level, and so on, so that a member of the marketing department viewing the same paragraph at the same time in the same presentation as a member of the research department will in fact be shown a different version of the paragraph. A graphic diagram of a subsystem presented to the marketer will be a simpler version than the one shown at the same time to the researcher. More particularly, methods, systems, and computer program products are disclosed for differential dynamic content delivery. Typical embodiments include providing a session document for a presentation, wherein the session document includes a session grammar and a session structured document; receiving a prerecorded presentation control instruction; selecting from the session structured document a classified structural element in dependence upon the prerecorded presentation control instruction and in dependence upon user classifications of a user participant in the presentation; and presenting the selected structural element to the user. In typical embodiments, the prerecorded presentation control instruction has an associated time stamp. Typical embodiments also include creating a prerecorded presentation session, including repeatedly: recording a presentation control instruction; and recording a time stamp in association with the presentation control instruction. Many embodiments also include creating the presentation control instruction, including: receiving from a user participating in the presentation a key phrase and optional parameters for invoking a presentation action; and parsing the key phrase and parameters against a voice response grammar into a presentation control instruction. In some embodiments, the prerecorded presentation control instruction includes a presentation action identifier and optional parameters and selecting a classified structural element includes selecting a classified structural element in dependence upon the presentation action identifier and the parameters. In typical embodiments, selecting a classified structural element includes selecting a classified structural element having an associated classification identifier that corresponds to the user classification. In many embodiments, presenting the selected structural element to the user includes selecting a data communications protocol for the presentation; inserting the selected structural element in a data structure appropriate to the data communications protocol; and transmitting the data structure to the user according to the data communications protocol. Many embodiments also include creating a session document from a presentation document, including identifying a presentation document for a presentation, the presentation document including a presentation grammar and a structured document having structural elements classified with classification identifiers; identifying a user participant for the presentation, the user having a user profile comprising user classifications; and filtering the structured document in dependence upon the user classifications and the classification identifiers. In typical embodiments, filtering the structured document includes extracting, from the structured document, structural elements having classification identifiers corresponding to the user classifications and writing the extracted structural elements into a session structured document in the session document. Some embodiments also include filtering the presentation grammar, in dependence upon the extracted structural elements, into a session grammar in the session document. Many embodiments of the present invention include creating a presentation document, including creating, in dependence upon an original document, a structured document comprising one or more structural elements; classifying a structural element of the structured document according to a presentation attribute; and creating a presentation grammar for the structured document, wherein the presentation grammar for the structured document includes grammar elements each of which includes an identifier for at least one structural element of the structured document. In many embodiments, classifying a structural element includes identifying a presentation attribute for the structural element identifying a classification identifier in dependence upon the presentation attribute and inserting the classification identifier in association with the structural element in the structured document. In some embodiments, creating a presentation grammar for the structured document includes identifying the content type of the original document; selecting, in dependence upon the content type, a full presentation grammar from among a multiplicity of full presentation grammars; and filtering the full presentation grammar into a presentation grammar for the structured document in dependence upon the structural elements of the structured document. The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular descriptions of exemplary embodiments of the invention as illustrated in the accompanying drawings wherein like reference numbers generally represent like parts of exemplary embodiments of the invention. | 20040113 | 20110816 | 20050714 | 68830.0 | 0 | TAPP, AMELIA L | DIFFERENTIAL DYNAMIC CONTENT DELIVERY WITH PRESENTATION CONTROL INSTRUCTIONS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,756,180 | ACCEPTED | Broadhead with fixed replaceable blades | A broadhead for use with an arrow, includes a one piece body having a penetrating end, a shank formed integral therewith and depending from the penetrating end and an arrow engaging end formed integral therewith and depending from the shank, a continuous circumferential blade retaining lip being defined on the one piece body. And, a plurality of replaceable main blades, each of the plurality of main blades having a leading edge and a trailing edge, a retaining edge being defined proximate the leading edge, the retaining edge of each of the plurality of blades being retainingly disposed in the continuous circumferential blade retaining lip when each of the main blades is operably coupled to the one piece body. A method of forming such a broadhead is further included. | 1. A broadhead for use with an arrow, comprising: a one-piece single component body having a penetrating end, a shank formed integral therewith and depending from the penetrating end and an arrow engaging end formed integral therewith and depending from the shank, a continuous circumferential blade retaining lip being defined on the one-piece single component body; and a plurality of replaceable main blades, each of the plurality of main blades being non-expandable and having a leading edge and a trailing edge, a retaining edge being defined proximate the leading edge, the retaining edge of each of the plurality of blades being retainingly disposed in the continuous circumferential blade retaining lip when each of the main blades is operably coupled to the one-piece single component body. 2. The broadhead of claim 1 having a tip blade operably coupled to the penetrating end of the one-piece single component body. 3. The broadhead of claim 2, wherein the tip blade is disposed in a transverse slot defined in the penetrating end of the one-piece single component body. 4. The broadhead of claim 2 wherein the tip blade is replaceably disposed in a transverse slot defined in the penetrating end of the one-piece single component body and held therein by a removable retainer, the retainer penetrating both the tip blade and the penetrating end. 5. The broadhead of claim 1, each of the plurality of blades having a lightening slot defined therein. 6. The broadhead of claim 1, each of the plurality of blades being held in operable engagement with the one-piece single component body by the arrow being operably coupled to the arrow engaging end of the one-piece single component body. 7. The broadhead of claim 1, each of the plurality of blades being held in operable engagement with the one-piece single component body at least in part by a respective groove defined in the one-piece single component body. 8. The broadhead of claim 7, each of the plurality of blades being free to translate in the respective groove defined in the one-piece single component body. 9. The broadhead of claim 1, the continuous circumferential blade retaining lip being defined at an intersection of the penetrating end and the shank. 10. The broadhead of claim 1, the continuous circumferential blade retaining lip being defined at an angle, the angle being directed inwardly and upwardly toward the penetrating end from a penetrating end circumferential margin. 11. The broadhead of claim 1, the continuous circumferential blade retaining lip being formed at an angle of between substantially 10 and 75 degrees relative to a broadhead longitudinal axis. 12. The broadhead of claim 11, the continuous circumferential blade retaining lip being formed at an angle of 45 degrees relative to the broadhead longitudinal axis. 13. (canceled) 14. A broadhead for use with an arrow, comprising: a one-piece single component body, a continuous circumferential blade retaining lip being defined thereon, the continuous circumferential blade retaining lip being defined at an angle, the angle being directed inwardly and upwardly toward the penetrating end from a penetrating end circumferential margin; a plurality of replaceable main blades each of the plurality of main blades being non-expandable and having a leading edge and a trailing edge, a retaining edge being defined proximate the leading edge the retaining edge of each of the plurality of blades being retainingly disposed in the continuous circumferential blade retaining lip when each of the main blades is operably coupled to the one-piece single component body; and a tip blade operably coupled to the penetrating end of the one-piece single component body. 15. The broadhead of claim 14, wherein the tip blade is disposed in a transverse slot defined in the penetrating end of the one-piece single component body. 16. The broadhead of claim 14 wherein the tip blade is replaceably disposed in a transverse slot defined in the penetrating end of the one piece single component body and held therein by a removable retainer, the retainer penetrating both the tip blade and the penetrating end. 17. The broadhead of claim 14, each of the plurality of blades having a lightening slot defined therein. 18. The broadhead of claim 14, each of the plurality of blades being held in operable engagement with the one-piece single component body by the arrow being operably coupled to the arrow engaging end of the one-piece single component body. 19. The broadhead of claim 14, each of the plurality of blades being held in operable engagement with the one-piece single component body at least in part by a respective groove defined in the one-piece single component body. 20. The broadhead of claim 19, each of the plurality of blades being free to translate in the respective groove defined in the one-piece single component body. 21. The broadhead of claim 14, the continuous circumferential blade retaining lip being defined at an intersection of the penetrating end and a shank. 22. The broadhead of claim 14, the continuous circumferential blade retaining lip being formed at an angle of between substantially 10 and 75 degrees relative to a broadhead longitudinal axis. 23. The broadhead of claim 22, the continuous circumferential blade retaining lip being formed at an angle of 45 degrees relative to the broadhead longitudinal axis. 24. (canceled) 25. A method of forming a broadhead for use with an arrow, comprising: forming a one-piece single component body; forming a continuous circumferential blade retaining lip defined thereon; defining the continuous circumferential blade retaining lip at an angle, the angle being directed inwardly and upwardly toward the penetrating end from a penetrating end circumferential margin; forming a plurality of replaceable main blades each of the plurality of main blades being non-expandable and having a leading edge and a trailing edge, a retaining edge being defined proximate the leading edge; retaining each of the plurality of blades in the continuous circumferential blade retaining lip when each of the main blades is operably coupled to the one-piece single component body; and forming a transverse slot in a penetrating end of the one-piece single component body, replaceably disposing a tip blade in the transverse slot, and retaining the tip blade therein by a removable retainer. 26. The method of claim 25 including holding each of the plurality of blades in operable engagement with the one-piece single component body at least in part by disposing a portion of each blade in a respective groove defined in the one-piece single component body. 27. The method of claim 25 including forming the continuous circumferential blade retaining lip at an angle of between 10 and 75 degrees relative to a broadhead longitudinal axis. 28. The broadhead of claim 27 including forming the continuous circumferential blade retaining lip at an angle of 45 degrees relative to the broadhead longitudinal axis. | TECHNICAL FIELD The present invention relates to broadheads for use with arrows in hunting applications. More particularly, this application relates to broadheads with fixed replaceable main blades. BACKGROUND OF THE INVENTION Broadheads are well known for use with arrows, primarily in the sport of big game hunting. Broadheads are designed to give reliable, deep penetration and to generate a large wound channel in order to humanely dispatch the target animal. Prior art broadheads including a number of different types. The first such type is an expandable broadhead having a retracted, inflight blade disposition in which the blade is held at least partially within the broadhead body. Upon impact, the blades expand outward to generate the required large wound channel. Such broadheads have the advantage of inflight stability and not the subject to the influence of cross winds. However, such broadheads are not of a relatively simple design, requiring some mechanism to shift the blades from the inflight-retracted disposition to the expanded penetrating disposition. A further type of prior art broadhead is one that can be characterized as having fixed main blades that are not replaceable. Such broadheads are typically formed in a unitary integral manner. While such blades are extremely simple in construction, a bent or dull blade is not easily rectified. A further type of prior art broadhead has fixed main blades that are replaceable by use of a multi-component body. The multi-component body may include a shank and a screw on penetrating tip. Removal of the penetrating tip from the shank allows the main blades to be replaced. Forming separate cooperative shanks and penetrating tips add significantly to the manufacturing cost of this type of broadhead. Another type of prior art broadhead is a broadhead having fixed main blades that are replaceable and a unitary body. Such broadheads typically have a multi-faceted penetrating tip with a blade-retaining notch presented at the trailing edge of the intersection of two facets. The blade-retaining notch captures the leading edge of a single main blade. The notch is typically not much wider than the thickness dimension of the blade. A difficulty with such broadheads is that an off axis penetration by the broadhead tends to dislodge the blade leading edge from the blade retaining notch. The blade then disadvantageously separates from the broadhead body and does not penetrate the target. What is needed in the industry then is a broadhead of simple unitary construction with readily replaceable main blades that has the reliability and penetrating characteristics of a broadhead having fixed main blades that are not replaceable. SUMMARY OF THE INVENTION The broadhead of the present invention substantially meets the aforementioned needs of the industry. The broadhead is simply constructed having a one-piece body to which a plurality of replaceable main blades are joined. The leading edge of each of the main blades is reliably retained within a continuous circumferential blade retaining lip defined on the body of the broadhead. Such design allows ready replacement of the main blades while at the same time ensuring that the main blades remain affixed to the broadhead body even during off axis penetrations. The present invention is a broadhead for use with an arrow and includes a one piece body having a penetrating end, a shank formed integral therewith and depending from the penetrating end and an arrow engaging end formed integral therewith and depending from the shank, a continuous circumferential blade retaining lip being defined on the one piece body. And, additionally includes a plurality of replaceable main blades, each of the plurality of main blades having a leading edge and a trailing edge, a retaining edge being defined proximate the leading edge, the retaining edge of each of the plurality of blades being retainingly disposed in the continuous circumferential blade retaining lip when each of the main blades is operably coupled to the one piece body. The present invention is further a method of forming such a broadhead. BRIEF DESCRIPTIONS OF THE DRAWINGS FIG. 1 is a side elevational view of the broadhead of the present invention including the broadhead body and a single main blade spaced apart therefrom. DETAILED DESCRIPTION OF THE DRAWINGS The broadhead of the present invention is shown generally at 10 in the figure. The broadhead 10 is designed to be removably affixed to an arrow 20, depicted in phantom. The arrow 20 is an elongate shaft 22. The shaft 22 terminates at a first end in a transverse end face 24. An axial bore 26 is defined depending from end face 24. The axial bore 26 may be a blind bore having a lower threaded bore portion 28. The broadhead 10 of the present invention has a one-piece body 30 and a plurality of main blades 32. While only a single main blade 32 is depicted, it is understood that a plurality of blades, preferably from two to five blades may be a arrayed around the circumference of the body 30. The one piece-body 30 of the broadhead 10 has three major subcomponents; a penetrating end 34 and a spaced apart opposed arrow engaging end 36 with a central shank 38 extending between the penetrating end 34 and the arrow engaging end 36. The penetrating end 34 of the one-piece body 30 has a pointed penetrating tip 40. A tip margin 42 extends from the penetrating tip 40 to an orthogonally disposed tip base 44. The tip margin 42 preferably has a generally increasing diameter taken from the penetrating tip 40 to the tip base 44. A continuous circumferential blade retaining lip 46 is defined inward and upward from the circumferential margin of the tip base 44. The circumferential blade retaining lip 46 preferably extends inward at an angle of between 15 and 75 degrees relative to the longitudinal axis 48 of the broadhead 10. Most preferably, the circumferential blade retaining lip 46 makes a 45-degree angle relative to the longitudinal axis 48. A transverse tip blade slot 50 is defined in the upper portion of the penetrating tip 40. The tip blade slot 50 passes through the retaining tip 40, preferably intersecting both the longitudinal axis 48 and the penetrating tip 40. The tip blade slot 50 preferably extends upward from a transverse base 52 to the penetrating tip 40. A tip blade bore 54 is defined through the penetrating end 34. Preferably, the tip blade bore 54 is disposed orthogonally with respect to the tip blade slot 50 and intersects the tip blade slot 50. A tip blade 56 is preferably disposed in the tip blade slot 50. The tip blade 56 has a blade base 58 that is preferably orthogonally disposed relative to the longitudinal axis 48 and which abuts the base 52 of the tip blade slot 50. The tip blade 56 has a pair of opposed cutting edges 60. Each of the cutting edges 60 may have a razor edge defined thereon and preferably extends from a tip 62 to the blade base 58. The cutting edges 60 may be curved and may mirror the shape of the tip margin 42. A retainer 64 may be disposed in the tip blade bore 54. The retainer 64 passes through the tip blade bore 54 and a bore (not shown) defined in the tip blade 56 that is in registry with the tip blade bore 54. The retainer 64 may be a pin that is pressed in, or more preferably, is a small bolt that is threaded into the tip blade bore 54, which may be removed in order to replace the tip blade 56. The shank 38 of the one-piece body 30 depends from the penetrating end 34. A cylindrical shank portion 66 extends from the inner margin of the circumferential blade retaining lip 46 downward to a bell shaped shank portion 68. The belled shank portion 68 has a generally increasing sectional diameter from the top to the bottom of the belled shank portion 68. A blade groove 72 is defined in and extends beyond the upper margin and lower margin of the shank 38. A blade groove 72 is provided corresponding to each of the plurality of main blades 32 to be employed on the broadhead 10. The blade groove 72 is a blind groove having generally parallel, spaced apart side margins and a bottom margin that is parallel to the longitudinal axis 48. The distance of the bottom margin of the blade groove 72 from the longitudinal axis 48 is generally equal to the radius of the cylindrical shank portion 66 of the shank 38. The arrow-engaging end 36 of the one-piece body 30 has a generally cylindrical shank 74 that depends from the shank 38 of the one-piece body 30. The shank 74 has an upper cylindrical portion 76 and a lower threaded portion 78. The lower threaded portion 78 is designed to threadably engage the threaded bore portion 28 of the axial bore 26 of the arrow 20. The second major component of the broadhead 10 is the main blade 32. As noted above, there may be a plurality of main blades 32 employed with the broadhead 10. Preferably, there are between two and five main blades 32 and most preferably three blades 32. The main blades 32 are equiangularly displaced around the circumference of the one-piece body 30. A blade groove 72 is defined in the one-piece body 30 corresponding to each of the main blades 32 to be employed with the broadhead 10. The thickness of the main blades 32 is preferably slightly less than the width of the blade groove 72 so that a portion of the main blade 32 may be removably, supportively disposed within the blade groove 72. The main blades 32 are generally triangular in shape. The main blade 32 has an axial edge 80. The axial edge 80 is a generally blunt edge and extends from a leading edge 92 of the blade 32, terminating at a trailing edge 96 in a retaining tail 82. The retaining tail 82 comprises a relatively small depending projection formed integral with the blade 32. When the main blade 32 is assembled to the body 30, the retaining tail 82 projects downward from the shank base 70 of the shank 38 of the body 30 and is fully disposed within the portion of the blade groove 72 that is formed in the arrow-engaging end 36 of the body 30. A base edge 84 is presented generally orthogonally with respect to the axial edge 80. The base edge 84 presents a generally blunt margin. A cutting edge 86 extends angularly upward from the base edge 84. The cutting edge 86 preferably has a razor edge 88 presented at the margin of the cutting edge 86. At the leading edge 92 of the blade 32, the cutting edge 86 is joined to the base edge 84 by a retaining edge 90. The retaining edge 90 presents a generally blunt margin. The retaining edge 90 is designed to cooperate with the circumferential blade retaining lip 46 in order to secure the leading edge 92 of the blade 32 to the one-piece body 30 in a readily removable manner. Accordingly, the angle of the retaining edge 90 relative to the axial edge 80 is generally the same as the angle of the circumferential blade retaining lip 46 with respect to the longitudinal axis 48. Preferably, the angle of the retaining edge 90 relative to the axial edge 80 is 45 degrees. A lightening slot having any desired shape may be defined in each of the blades 32. In assembly, each of the blades 32 is positioned within a respective blade groove 72. In this disposition, the axial edge 80 of the blade 32 is generally parallel to and spaced apart from the longitudinal axis 48 of the body 30. The upper portion of the axial edge 82 lies flush with the exterior margin of the cylindrical shank portion 66. The lower portion of the axial edge 80 resides with the blade groove 72. With the blades 32 held loosely in this disposition, the arrow 20 is threadably engaged with the broadhead 10. The threaded bore portion 28 of the arrow 20 is engaged with the lower threaded portion 78 of the arrow-engaging end 36. As the arrow 20 advances upward, the end face 24 of the arrow 20 bears on the base edge 84 of each of the blades 32, causing the retaining edge 90 to be retained within the circumferential blade retaining lip 46. When the arrow 20 is snugged up against the broadhead 10, the end face 24 of the arrow 20 bears on the shank base 70 and the base edge 84 of the blade 32 is held flush with the shank base 70 of the shank 38. In this disposition, the retaining tail 82 of the blade 32 is captured cooperatively within the blade groove 72 by the axial bore 26 of the arrow 20. In this manner, both the leading edge 92 and trailing edge 96 of each of the main blades 32 is held in engagement with the one-piece body 30. To remove the blades 32 from the body 30, the arrow 20 is simply unthreaded from the broadhead 10. Holding the broadhead 10 as depicted in FIG. 1, as the arrow 20 retreats from the broadhead 10 the blades 32 will simply fall free from the one-piece body 30 when the retaining edge 90 has cleared the circumferential blade retaining lip 46. It will be obvious to those skilled in the art that other embodiments in addition to the ones described herein are indicated to be within the scope and breadth of the present application. Accordingly, the applicant intends to be limited only by the claims appended hereto. | <SOH> BACKGROUND OF THE INVENTION <EOH>Broadheads are well known for use with arrows, primarily in the sport of big game hunting. Broadheads are designed to give reliable, deep penetration and to generate a large wound channel in order to humanely dispatch the target animal. Prior art broadheads including a number of different types. The first such type is an expandable broadhead having a retracted, inflight blade disposition in which the blade is held at least partially within the broadhead body. Upon impact, the blades expand outward to generate the required large wound channel. Such broadheads have the advantage of inflight stability and not the subject to the influence of cross winds. However, such broadheads are not of a relatively simple design, requiring some mechanism to shift the blades from the inflight-retracted disposition to the expanded penetrating disposition. A further type of prior art broadhead is one that can be characterized as having fixed main blades that are not replaceable. Such broadheads are typically formed in a unitary integral manner. While such blades are extremely simple in construction, a bent or dull blade is not easily rectified. A further type of prior art broadhead has fixed main blades that are replaceable by use of a multi-component body. The multi-component body may include a shank and a screw on penetrating tip. Removal of the penetrating tip from the shank allows the main blades to be replaced. Forming separate cooperative shanks and penetrating tips add significantly to the manufacturing cost of this type of broadhead. Another type of prior art broadhead is a broadhead having fixed main blades that are replaceable and a unitary body. Such broadheads typically have a multi-faceted penetrating tip with a blade-retaining notch presented at the trailing edge of the intersection of two facets. The blade-retaining notch captures the leading edge of a single main blade. The notch is typically not much wider than the thickness dimension of the blade. A difficulty with such broadheads is that an off axis penetration by the broadhead tends to dislodge the blade leading edge from the blade retaining notch. The blade then disadvantageously separates from the broadhead body and does not penetrate the target. What is needed in the industry then is a broadhead of simple unitary construction with readily replaceable main blades that has the reliability and penetrating characteristics of a broadhead having fixed main blades that are not replaceable. | <SOH> SUMMARY OF THE INVENTION <EOH>The broadhead of the present invention substantially meets the aforementioned needs of the industry. The broadhead is simply constructed having a one-piece body to which a plurality of replaceable main blades are joined. The leading edge of each of the main blades is reliably retained within a continuous circumferential blade retaining lip defined on the body of the broadhead. Such design allows ready replacement of the main blades while at the same time ensuring that the main blades remain affixed to the broadhead body even during off axis penetrations. The present invention is a broadhead for use with an arrow and includes a one piece body having a penetrating end, a shank formed integral therewith and depending from the penetrating end and an arrow engaging end formed integral therewith and depending from the shank, a continuous circumferential blade retaining lip being defined on the one piece body. And, additionally includes a plurality of replaceable main blades, each of the plurality of main blades having a leading edge and a trailing edge, a retaining edge being defined proximate the leading edge, the retaining edge of each of the plurality of blades being retainingly disposed in the continuous circumferential blade retaining lip when each of the main blades is operably coupled to the one piece body. The present invention is further a method of forming such a broadhead. | 20040113 | 20050913 | 20050714 | 63514.0 | 1 | RICCI, JOHN A | BROADHEAD WITH FIXED REPLACEABLE BLADES | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,756,218 | ACCEPTED | Methods and systems for maintaining color consistency in a print-on-demand workflow | Methods and systems for maintaining color consistency in print-on-demand applications are disclosed. Initially, a plurality of default color settings applicable to a plurality of print-on-demand operations can be established. Thereafter, color consistency can be selectively imposed across a plurality of print-on-demand operations based on the plurality of default color settings applicable to the plurality of print-on-demand operations. Finally, a print-on-demand media product can be rendered in response to selectively imposing color consistency across the plurality of print-on-demand operations. An end-to-end print-on-demand workflow is therefore disclosed herein that describes how to create and print color books while maintaining color consistent at each step of in the work follow. | 1. A method, comprising: initially establishing a plurality of default color settings applicable to a plurality of print-on-demand operations; thereafter selectively imposing color consistency across a plurality of print-on-demand operations based on said plurality of default color settings applicable to said plurality of print-on-demand operations; and rendering a print-on-demand media product, in response to selectively imposing color consistency across said plurality of print-on-demand operations. 2. The method of claim 1 further comprising determining if an imposition operation is necessary in response to initially establishing said plurality of default color settings applicable to said plurality of print-on-demand operations. 3. The method of claim 1 wherein selectively imposing color consistency across a plurality of print-on-demand operations based on said plurality of default color settings applicable to said plurality of print-on-demand operations, further comprises: selecting color-proofing elements from an electronic document to be rendered as a print-on-demand product. 4. The method of claim 1 wherein selectively imposing color consistency across a plurality of print-on-demand operations based on said plurality of default color settings applicable to said plurality of print-on-demand operations, further comprises: analyzing an electronic document to be rendered as a print-on-demand product for high-resolution images thereof; and if at least one high-resolution image is identified in association with said electronic document, transferring said at least one high-resolution image to a database for storage and retrieval thereof. 5. The method of claim 1 further comprising: proofing an electronic document to be rendered as a print-on-demand product, wherein said electronic document is associated with at least one color image; and establishing submission path parameters during proofing of said electronic document; and thereafter automatically printing said electronic document as a hardcopy document including said at least one color image, wherein said printing is based on said submission path parameters. 6. The method of claim 5 further comprising automatically trimming and binding said hardcopy document. 7. The method of claim 1 wherein rendering a print-on-demand media product, in response to selectively imposing color consistency across said plurality of print-on-demand operations, further comprises: printing said print-on-demand media product, wherein said print-on-demand media product comprises a book that includes a plurality of color images that match said plurality of default color settings. 8. The method of claim 7 further comprising saving said an electronic copy of said book in a network file system, wherein said electronic copy can be subsequently retrieved and said book automatically reprinted, including color images associated with said electronic copy. 9. The method of claim 1 further comprising: identifying color images associated with an electronic document to be rendered as a print-on-demand product; and automatically rearranging said color images so that said color images can be rendered in association with said print-on-demand product. 10. A method, comprising: initially establishing a plurality of default color settings applicable to a plurality of print-on-demand operations; thereafter selectively imposing color consistency across a plurality of print-on-demand operations based on said plurality of default color settings applicable to said plurality of print-on-demand operations; and automatically proofing an electronic document to be rendered as a print-on-demand product, wherein said electronic document is associated with at least one color image; and establishing submission path parameters during proofing of said electronic document; thereafter rendering a print-on-demand media product, in response to selectively imposing color consistency across said plurality of print-on-demand operations, by automatically printing said electronic document as a hardcopy document including said at least one color image, wherein said printing is based on said submission path parameters. 11. A system, comprising: a color setting module for establishing a plurality of default color settings applicable to a plurality of print-on-demand operations; a selection module for thereafter selectively imposing color consistency across a plurality of print-on-demand operations based on said plurality of default color settings applicable to said plurality of print-on-demand operations; and a rendering module for rendering a print-on-demand media product, in response to selectively imposing color consistency across said plurality of print-on-demand operations. 12. The system of claim 11 further comprising determining if an imposition operation is necessary in response to initially establishing said plurality of default color settings applicable to said plurality of print-on-demand operations. 13. The system of claim 11 wherein said selection module for selectively imposing color consistency across a plurality of print-on-demand operations based on said plurality of default color settings applicable to said plurality of print-on-demand operations, further comprises: a selection module for selecting color-proofing elements from an electronic document to be rendered as a print-on-demand product. 14. The system of claim 11 wherein said selection module for selectively imposing color consistency across a plurality of print-on-demand operations based on said plurality of default color settings applicable to said plurality of print-on-demand operations, further comprises: a module for analyzing an electronic document to be rendered as a print-on-demand product for high-resolution images thereof; and a module for transferring at least one high-resolution image to a database for storage and retrieval thereof, if said at least one high-resolution image is identified in association with said electronic document 15. The system of claim 11 further comprising: an electronic document to be rendered as a print-on-demand product, wherein said electronic document is associated with at least one color image; and a module for establishing submission path parameters during proofing of said electronic document; and a module for automatically printing said electronic document as a hardcopy document including said at least one color image, wherein said printing is based on said submission path parameters. 16. The system of claim 15 further comprising a module for automatically trimming and binding said hardcopy document. 17. The system of claim 11 wherein said rendering module for rendering a print-on-demand media product, in response to selectively imposing color consistency across said plurality of print-on-demand operations, further comprises: print module for printing said print-on-demand media product, wherein said print-on-demand media product comprises a book that includes a plurality of color images that match said plurality of default color settings. 18. The system of claim 17 further comprising a module for saving said an electronic copy of said book in a network file system, wherein said electronic copy can be subsequently retrieved and said book automatically reprinted, including color images associated with said electronic copy. 19. The system of claim 11 further comprising: a module for identifying color images associated with an electronic document to be rendered as a print-on-demand product; and a module for automatically rearranging said color images so that said color images can be rendered in association with said print-on-demand product. 20. The system of claim 11 wherein said color setting module, said selection module and said rendering module comprise a print-on-demand module comprising signal bearing media storable within a memory location of a computer. | TECHNICAL FIELD Embodiments are generally related to print-on-demand (POD) applications, devices and techniques thereof. Embodiments are also related to techniques for incorporating color rendering into POD applications. BACKGROUND OF THE INVENTION Print-on-demand (POD) for books involves the on demand, printing, binding and trimming of bound books. POD is also applicable to other publications and media that require finishing. Typically, bound books comprise a stacked plurality of text pages referred to as a book block, which includes one edge that is known to as the spine. The cover is of a suitable cover stock that is generally thicker and/or heavier than the text pages comprising the book block. The cover has a front portion that overlies the front of the book block, a back portion that overlies the back of the book block, and a center portion spanning across the spine of the book block. A suitable adhesive can be applied between the spine of the book block and the inside face of the center portion of the cover. The spine of the book block (i.e., the edges of the text pages along one edge of the book block) can be imbedded in the adhesive which, upon curing, securely adheres the pages of the book block to one another and to the center portion of the cover, thereby permitting the book to be opened to any page without the pages coming loose. In high volume production processes for manufacturing such bound books, the pages of each book block are usually jogged by specially developed machines prior to the application of adhesive so as to insure that the edges of the pages are properly aligned with one another. The adhesive, typically a suitable hot melt adhesive, is then applied to the spine of the book block. The cover, which is usually pre-printed, is then folded around the front, spine, and back of the book block and is firmly clamped to the book block proximate the spine during assembly. In this manner, the adhesive is firmly pressed between the spine of the book block and the inner face of the center portion of the cover to properly adhere the cover to the book block while simultaneously adhering the pages to one another. Typically, bound books are printed on pages that are somewhat larger than the desired size (i.e., the length and width) of the finished and bound book to be produced. These books, after they are bound, are typically trimmed along three sides to the desired final dimension in a separate trimming machine. Heretofore, such operations were carried out in separate machines that required considerable adjustment to bind books of different sizes and thus were best suited for production runs of many books. In addition, both prior art binding machines and trimming machines were very expensive. In recent years, book printing has undergone changes as computer technology and laser printers have advanced. This new technology now allows for machines capable printing perfect bound books “on-demand”. This new technology is often referred to as print-on-demand (POD). Such POD printed books come in a variety of formats and thicknesses (i.e., the number of pages in the book). Note that the terms “printing-on-demand” and “print-on-demand” are generally utilized interchangeably and refer to the same acronym “POD”. One example of a print-on-demand (POD) system is disclosed in U.S. Pat. No. 5,995,721, “Distributed Printing System,” which issued to Rourke et al. on Nov. 30, 1999. U.S. Pat. No. 5,995,721 generally discloses document processing system including at least one document reproduction apparatus and managing on-demand output of a document job. The document job is characterized by a set of job attributes with each job attribute relating to a manner in which the document job is to be processed by the document processing system. The document processing system, which further includes a document server for managing conversion of the document job into the on-demand output, includes: a plurality of queues mapped to a plurality of document processing subsystems, each of the plurality of queues including a set of queue attributes characterizing the extent to which each document processing subsystem mapped to one or more of the plurality of queues is capable of processing a job portion delivered to the one or more queues. Another example of a print-on-demand system is disclosed U.S. Pat. No. 5,832,193, “Method and apparatus for printing a label on the spine of a bound document,” which issued to Perine et al on Nov. 3, 1998. U.S. Pat. No. 5,832,193 generally describes a printing system for printing a representation of an image on a first portion of a bound document with the image being disposed on a second portion of the bound document is provided. The printing system includes an input station for generating a print job including the image, and a printing machine, communicating with the input station, for producing prints corresponding with the job, wherein one of the prints includes the image as a printed image. The printing system of U.S. Pat. No. 5,832,193 further includes a spine printing apparatus including an image capture system for reading the printed image and converting the same to a set of image data; and a printing device for printing the representation of the image, by reference to the set of image data, on the first portion of the bound document. Note that both U.S. Pat. Nos. 5,995,721 and 5,832,193 are incorporated herein by reference. Note, however, that neither U.S. Pat. Nos. 5,995,721 nor 5,832,193 constitute essential matter. Such patents are referenced herein for general edification and background purposes only. Books and other publications created for print-on-demand (POS) applications can therefore be mastered (i.e., run through a pre-press process), placed in a repository, and then printed, bound and trimmed when an order for the book arrives. One of the primary problems that current POD systems encounter is that color does not remain constant at each step in the workflow. While the industry has produced standards that facilitate consistent color throughout printing and other associated workflow processes, the actual applications have lagged behind in implementing such standards. As a result, the deployment of digital, on-demand printing systems, in addition to the complexity of other technologies has prevented many users from deploying correctly implementing such workflows, at least with respect to color rendering. A need thus exists for improved methods and systems for permitting the deployment of POD systems for color publishing, such as color books. An end-to-end workflow for creating and printing color books while maintaining color consistent at each step in the workflow is needed. BRIEF SUMMARY It is, therefore, a feature of the present invention to provide for improved print-on-demand (POD) methods and systems. It is another feature of the present invention to provide for improved color rendering methods and systems. It is also a feature of the present invention to provide for POD methods and systems that incorporate color rendering capabilities. It is additionally a feature of the present invention to provide for an improved POD workflow in which color consistency is maintained through out a POD workflow. Aspects of the present invention relate to methods and systems for maintaining color consistency in print-on-demand applications. Initially, a plurality of default color settings applicable to a plurality of print-on-demand operations can be established. Thereafter, color consistency can be selectively imposed across a plurality of print-on-demand operations based on the plurality of default color settings applicable to the plurality of print-on-demand operations. Finally, a print-on-demand media product can be rendered in response to selectively imposing color consistency across the plurality of print-on-demand operations. An end-to-end print-on-demand workflow is therefore disclosed herein that describes how to create and print color books while maintaining color consistency at each step of in the workflow. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying figures and non-limiting examples thereof, in which like reference numerals refer to identical or functionally-similar elements throughout the separate views and which are incorporated in and form part of the specification further illustrate embodiments of the present invention. FIG. 1 illustrates a block diagram depicting digital book preparation options, which can be implemented in accordance with a preferred embodiment of the present invention; FIG. 2 illustrates an operational schematic diagram of a color book preparation system in accordance with a preferred embodiment of the present invention; FIG. 3 illustrates a high-level flow chart depicting color book prepress and print workflow operations in accordance with a preferred embodiment of the present invention; FIG. 4 illustrates a simple dot gain model in accordance with a preferred embodiment of the present invention; FIG. 5 illustrates a block diagram of a color profile usage system in accordance with a preferred embodiment of the present invention; FIG. 6 illustrates a high-level flow chart depicting an imposition workflow in accordance with a preferred embodiment of the present invention; FIG. 7 illustrates a schematic diagram depicts results of applying a digital book 1-up imposition to a 100-page book in accordance with a preferred embodiment of the present invention; and FIG. 8 illustrates a block diagram depicting the geometry of a 1-up imposition in accordance with a preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION The particular values and configurations discussed in these non-limiting examples can be varied and are cited merely to illustrate embodiments of the present invention and are not intended to limit the scope of the invention. FIG. 1 illustrates a block diagram depicting a system 100 of digital book preparation options, which can be implemented in accordance with a preferred embodiment of the present invention. System 100 depicts a variety of digital book preparation workflow options that may precede the submission of an electronically formatted book file to a color book solution preparation environment, which is indicated at block 140 of FIG. 1. Several options are thus depicted in FIG. 1, including a first option, which is represented generally by blocks 102, 104, 105, 106, and 108. A second option is generally represented by blocks 112, 114, 115, 116, and 110. A third option is generally indicated by blocks 122, 124, 125, 126, and 128. Finally, a fourth option can be represented by blocks 132, 134, 135, and 136 of FIG. 1. System 100 is generally divided into eight columns, indicated by repository boxes 104, 105, 114, 115, 124, 125, 134, and 135, and their respective vertical workflow operational associations. Each column represents a set of operations that can be utilized to produce a book that can be manufactured via the color book solution indicated by block 140. Note that color images are commonly represented as one or more separations, each separation comprising a set of color density signals for a single primary or secondary color. Color density signals are commonly represented as digital pixels, which vary in magnitude from a minimum to a maximum, with a number of gradients corresponding to the bit density of the system. Thus, for example, a common 8-bit system can provide 256 shades of each primary color. A color can therefore be considered as the combination of magnitudes of each pixel, which when viewed together present the combination color. Usually, printer signals include three subtractive primary color signals (i.e., Cyan, Magenta and Yellow) and a Black signal, which together can be considered the printer colorant signals. Each color signal forms a separation, and when combined together with the other separations forms the color image. Note that the term “CMYK” generally refers to four colors utilized in printing processes, which are cyan, magenta, yellow, and black. The workflow in the far left column of FIG. 1 represents the creation of a book that contains original CMYK color encoding and uses OPI for which a resulting imposition is deferred. The acronym OPI generally refers to Open Prepress Interface (OPI), which is an extension of the PostScript page-description language that enables the design of pages with low-resolution images, followed by a replacement of such images with high-resolution images when printing separations. PostScript is well-known page description language developed that allows entire pages to be sent describing graphics and text to a printer. The flexibility allows more than just normal ASCII characters to be sent and is the de-facto standard in high end printing. The second column from the left, as indicated in FIG. 1, represents the same workflow as the first column, except that this second column does not utilize OPI. As indicated at block 105, the high-resolution images are simply embedded. Note that as indicated at block 110, the use of a color server is optional. A user can either submit the book files to the color book solution (i.e., see block 140) thereby retaining the original CMYK encoding, or the user can utilize a photo shop software application or a batch color management application to transform the original CMYK encoding to a color book solution printer-specific CMYK application prior to the original submission of the book files. The workflow in the fifth column (i.e., see block 124) represents the creation of a book that contains printer specific color encoding and uses OPI (has For Placement Only images (FPO) with links to the externally stored high-resolution images) for which the imposition has been deferred (i.e., the pages are 1-up). The sixth column (i.e., see block 125) from the left represents the same workflow as the fifth, except that it does not use OPI (i.e., the high-resolution images are embedded). The workflow in the seventh column (i.e., see block 134) represents the creation of a book that contains printer specific color encoding, and uses OPI and an imposed PDF original. The eighth column from the left (i.e., see block 135) represents the same workflow as the seventh, except that it does not use OPI (i.e., the high-resolution images are embedded). To incorporate digital printing into an offset workflow, one must determine which digital book preparation workflow will be utilized. To accomplish this, each method, such as OPI, storage color encoding and imposition, must be evaluated for utilization with the current workflow. The columns of FIG. 1 illustrate various workflow combinations that can result. Working with the options depicted in FIG. 1, workflow processes can be identified along with the appropriate column that coincides with user selections. All of the columns can then be eliminated, except the one required. For example, if OPI is utilized, then columns 1, 3, 5 and 7 are appropriate options. If a user prefers to archive imposed book files, then either columns 3, 4, 7, or 8 should be selected. Alternatively, if a user prefers to retain the original CMYK color encoding until print run time, then columns 1, 2, 3, or 4, are appropriate choices. Only column 3 is available via all three methods. Therefore, column 3 represents the functionality of a preferred digital book preparation workflow. For the purpose of archiving (short or long term) a near-print-ready book block, a user may wish to establish an archive of book jobs that have been processed through a preferred digital book preparation workflow. Moving from black and white digital printing to color content printing may necessitate including new processes in the printing workflow. Color files, because of their 3× to 10× file sizes (i.e., compared to similar black and white files) may require new file management processes. OPI methods can be used to improve application performance and network transmission times in printing workflows with significant high-resolution color image content. Color encoding choices for archived original files, archived near-print-ready files, and work-in-progress files must be considered in the context of customer needs, the range of targeted outputs, and long-term digital asset management strategy. In transitioning from offset to digital, reference can be made to FIG. 1 to select a preferred workflow processes. OPI and color encoding should be considered at each point in the workflow, and the imposition utilized in the current workflow. The columns of FIG. 1 depict various workflow combinations that result. Working with the options depicted in FIG. 1, the workflow processes can be identified and the column that coincides with user selections. All columns can then be eliminated except the one required. For example, if a user determines to upgrade to utilizing OPI then columns 1, 3, 5, and 7 are appropriate options. If the user prefers to archive un-imposed book files (e.g., impose on the print path), then either columns 1, 2, 5, or 6 should be selected. If, however, the user expects to receive book files in CMYK (i.e. the original CMYK encoding), the books files should be stored in this encoding, and then converted to a printer CMYK format using a batch color management tool immediately prior to submission to the color book solution depicted in block 140. Columns 1, 2, 3, or 4 are therefore appropriate choices. Only column 1 is present in all three aforementioned methods. Therefore, column 1 can represent the functionality of a preferred digital book preparation workflow. For the purpose of archiving (i.e., short- or long-term) a near-print-ready book block, a user may wish to establish an archive of book jobs that have been processed through the user's preferred digital book preparation workflow. FIG. 2 illustrates an operational schematic diagram of a color book preparation system 200 in accordance with a preferred embodiment of the present invention. System 200 describes in general, an end-to-end color book workflow process. As indicated at block 202, the monitor utilized in a printing workstation should be calibrated and characterized. Note that an example of a document creation workstation intended for use with system 200 of FIG. 2 generally requires at least 256 MB RAM and should be configured with a minimum of 512 MB of virtual memory. A typical photo shop application, for example, requires approximately 128 MB. Additionally, such a workstation should be configured with at least a 20 GB local hard drive. The workflow described herein with respect to preferred and alternative embodiments generally can accept page PDF book files (i.e., not yet imposed), with all color data encoded in a color managed CMYK format. Such a workflow also functions with high-resolution images referenced utilizing OPI commands in the PDF document itself. All fonts thereof can also be embedded. Such constraints generally correspond to the process of column 1 of FIG. 1, but or course, other configurations are possible. Following processing of the operation depicted at block 204, a book cover and block can be created in a printing application. All images thereof can be included, for example, in TIFF or JPEG format, depending upon the desired application. If a user utilizes O PI, low-resolution TIFF images can be included in the electronic book file. High resolution TIFF images can be located in a memory location of an associated server. The entire document can be exported to PostScript from the document application. A distiller application can then be utilized to convert the PostScript file to a PDF file. Thereafter, as depicted at block 206, a test is performed to determine if an associated repository contains imposed books. If, so the book block and/or book cover can be imposed as indicated at block 208 and the imposed book saved as one or more PDF files, as depicted at block 210. If not, then as depicted at block 207, the user should plan to impose the book prior to printing thereof. Blocks 212-220 of system 200 generally describe the actual printing process. As indicated initially at block 212, the actual order for the book can arrive at the printshop and thereafter, as indicated at block 214, the print book block and cover can be printed. Next, as depicted at block 216, the printed book block and cover can be inspected. Thereafter, as depicted at block 218, the printed book block and cover can be bound together. Finally, as indicated at block 220, the bound book can be trimmed. FIG. 3 illustrates a high-level flow chart 300 depicting color book prepress and print workflow operations in accordance with a preferred embodiment of the present invention. The process can be initiated, as indicated at block 301. A client file system 302 can provide necessary electronic data for the process depicted in FIG. 3. As described at block 303, grounds rules can be established and verification checks performed prior to continuing the prepress and print workflow operations thereof. According to the operation illustrated at block 303, an operator can perform a “preflight” verification PDF near-print ready files are formatted, fonts are embedded, high resolution images are OPI linked, and CMYK color encoding is implemented. An example of a “preflight verification” software application which can be utilized in accordance with one embodiment herein is the “FLIGHTCHECK®” software available from Markzware, Inc., a company based in Santa Clara, Calif. “FLIGHTCHECK®” is a registered trademark of Markzware, Inc. The operation illustrated at block 303 thus generally involves establishing a default set of FLIGHTCHECK® settings, called Ground Rules, for use in the “preflighting” process. Such Ground Rules can be modified. Alternatively, specialized Ground Rules can be added over time particular issues are identified with respect to the book files that the user receives. Following processing of the operation illustrated at block 303, a test can be performed to determine if an imposition is necessary, as indicated at block 304. Such a test can actually be automatically performed via software applications or can be initiated at the behest of the operator. If an imposition is required, then as illustrated at block 305, an imposition is performed for the print and finishing path. The operation depicted at block 306 can then be processed. If, however, an imposition is not required, then the operation illustrated at block 306 is processed immediately after the operation depicted at block 304. According to the operation illustrated at block 306, layout and content visual proofing can occur (i.e., softcopy proofing). Such a proofing operation, however, is not for color. An operator may utilize an application such as Adobe Acrobat 4.0 for the layout and content visual proofing operation depicted at block 306. Thereafter, as depicted at block 308, a color and layout visual proof operation can be implemented. Block 308 generally refers to hardcopy proofing of representative pages, the book block, the book cover and so forth. An operator can select color-proofing elements utilizing an application such as Adobe Acrobat 4.0. Next, as indicated at block 312, a high resolution image file transfer operation to an OPI directory can be implemented. If the book PDF's contain OPI high-resolution image links, all of the high-resolution images can also be transferred to the OPI directory. Thereafter, as indicate at block 314, the actual job submission should be proofed. Color book proof jobs can be submitted via Windows-based personal computer or a Macintosh computer. The operator can submit selected pages, the entire book, and/or the book cover utilizing applications such as Adobe Acrobat 4.0 and a an Adobe Printer Driver or simply via a “Print” icon of a printing application. Following processing of the operation depicted at block 314, another test can be implemented, as indicated at block 316. An operator decision can determine whether or not the book is ready to print. If the book is not ready to print, then the processes beginning at block 306 are repeated. If, however, the book is ready to print, then as indicated at block 318, the book print is actually submitted. Color book jobs can be submitted from client workstations, personal computers, Macintosh computers, and the like. The operator can perform the operation depicted at block 318 utilizing submission path parameters as defined during a prior proofing step. Note that the color book media for the book block and covers should be validated. Offline processes for validation can include, for example, validating the physical quality of media through printing and finishing, as well as customizing color tables as required in order to adjust for media white point. Next, as indicated at block 320, the book can actually be printed. The book can be stored electronically in its final format within a network file system of a database 321 and later re-printed as many times as necessary. Finally, as indicated at block 322, the book can be trimmed and bound. The process can then terminate as depicted at block 324. In general, color output results are affected by conditions across the entire creation-to-print workflow. There are seven key Color Control Factors. Color Control Factors are those elements of any capture-to-output color document system that must be addressed in order to achieve consistent color appearance—delivering stability, repeatability, and predictability in the first print and in all later prints. The color encoding used, the color encoding identification mechanism, and any embedded or linked color transformation data such as ICC source profiles or PostScript tables all contribute to the color source specification for each document. Color source specification is dependent on document and image file formats. Many image and document formats are restricted to a limited set of color encoding definitions. Two key issues here are unidentified source document colors (which frequently occurs because document formats do not support complete color encoding identification) and sub-optimally constrained source color gamut (due to constrained color processing early in the image to print workflow). Calibration is the term used to identify the control capability supplied with each device such that the device can be maintained consistently within its optimal operating range. Each device manufacturer is responsible for providing this capability with each imaging device. The challenge here is that while calibration for each device is proprietary, any device in the workflow that is not controlled (e.g., an uncalibrated computer display) can adversely impact color results on other devices in the workflow. Note also that there is an interdependency between source device calibration and original document color specification (i.e., the source device must be calibrated and characterized if the original document color is to be specified), as well as a linkage between device calibration and characterization. Characterization refers to the capability of measurement and modeling software, tools and procedures to represent the full range of color device behavior. The set of colors available to a device is called the device color space or device color gamut. Visualize a three-dimensional color encoding volume (e.g., a cube) in color space with medium gray at the center of the volume. The color-encoding volume, or color gamut, represents the colors that a device can interpret (e.g., a scanner) or display (e.g., a monitor or printer). Now imagine several of these color gamuts, each representing the colors that different devices can interpret (e.g., scanners, monitors, and printers do not have exactly the same color gamuts). Each of these color-encoding volumes coincides with the others at the visually common gray center. However, each of these color-encoding volumes may be larger or smaller than another, and may have quite a different shape at its outer boundary. These differences directly affect which visual colors can be represented in each color encoding volume, and hence, which visual colors can be displayed or captured on the represented device. Fundamentally, more volume equals more colors. The relationships between the device color gamuts can impact the final printed or displayed color across any creation-to-print workflow. Colors transformed from a larger color encoding volume to a smaller color encoding volume can only be approximated in the smaller volume. The record of the original, more visually colorful encoding is lost. Device-independent color encodings, defined through international standards (e.g., CIELAB, CIEXYZ, and the like) serve as connection points in an ICC-based or Postscript-based color management system. Other device-independent color encodings, such as Adobe RGB (i.e., 1998 version) in Photoshop 5.× and 6.0, can serve as intermediate working spaces used during the image creation and editing process. It is important to note that such RGB working spaces, although device-independent, do possess specific color gamuts, and therefore can impact the range of colors carried through a workflow. The characterization process provides device color gamut data for use in an ICC or Postscript color management workflow. The characterization process results in the unambiguous representation of characterization data in standard data formats such as an ICC profile or a PostScript table. Characterization methods are typically proprietary, but must be compatible with the encoding requirements of the external standards. Together, calibration and characterization data tables must form the bridge between specific device colors, device-independent intermediate color encodings, and the color translation algorithms that render the document colors for display at the various stages of the workflow. Color aim refers to the color preference of a customer. A color aim includes practices, conventions, and standards that comprise market- and geography-specific customer color print appearance preferences. Two classes of preferred color aims (i.e., also known as color expectations) can be identified based on distinct document creation processes. In some cases, those who work with color documents create the documents on PCs or workstations and use the onscreen document appearance to determine the preferred color rendering for print. That is, the acceptability of printed output is determined by the extent to which it is perceived to match the display. In other cases, color practitioners create color documents using their experience to mentally integrate computer display color appearance, printer color capabilities, real-world memory colors, and industry color standards, thereby establishing the preferred print color rendering. Computer display color appearance is the least important determinant for these color practitioners; the preferred rendering for hardcopy is that which matches their mental image. Color aim practices reflect customer color print appearance preferences and are established though proprietary practices, industry conventions, and standards specific to markets and geographies. In many cases, formal standards provide the starting point for proprietary printing aims developed within particular printing workflows, for particular customer environments. The characterization process, combined with appropriate end-to-end color management, provides the means for automating consistent delivery of preferred color print aims. When a target customer environment includes non-standard viewing conditions, those producing printed output must establish specialized aims for such conditions. Examples are prints sold in retail settings that must appeal to the consumer under in-store fluorescent lighting, and billboards or other printed materials that must hold their appeal in harsh-full-sun lighting. The color and resolution capabilities of each device determine how well that device will support the various market- and geography-specific color aim and image quality expectations. Colorant design, halftone design, color plane lay-down interactions, media design and inherent color response stability are the key contributors to device color behavior. These physical device attributes in turn constrain device capability to implement a particular color aim. The specific DFE/printer color and resolution attributes that can affect the design of a color book include factors such as color gamut (i.e., derived from colorant spectral attributes, colorant interactions and halftone screen); ink Limit (i.e., limited by colorant interactions at high densities); and printer resolution (e.g., dpi, printer-addressable spots). Other factors include screen frequencies (e.g., lines per inch (lpi), line screens, screen rulings); gray levels per halftone cell (e.g., traditionally: [output device resolution/line screen]{circumflex over ( )}2+1=shades of gray); minimum stroke (e.g., in a range of 0.15-0.5 points); and separation registration (e.g., in range of {fraction (1/64)} inch—indicates trapping needs). Additional factors include dot range (e.g., 5-95 percent dot); dot shapes (e.g., halftone dot design); dot gain (i.e., from initial rendering to final print, typically significantly less with digital print paths); and screen angles (traditionally: offset screen angles are black at 45-135-225-315, magenta at 75-165-255-345, cyan at 105-195-285-15, and yellow at 90-180-270-0). Common usage describes such values as 45, 75, 105, and 90. A complete description, however, should include all four angles for each separation. Screen frequencies may range from 133 lpi to more than 200 lpi for commercial print work. If line screen (screen frequency), dot shape, screen angle, and related attributes have been factored into the book design, then some adjustment may be required when retargeting the book to digital printing. FIG. 4 illustrates a simple dot gain model 400 in accordance with a preferred embodiment of the present invention. As indicated in model 400 of FIG. 4, midtone dots generally possess the longest perimeter, so they are the most affected by dot gain. Small dots possess a shorter perimeter than midtone dots. Large dots have much overlap and so also show less dot gain. In practice, the dot gain curve in a particular print path will be more complex. However, print path dot gain values are typically quoted for the 50 percent dot, with the assumption that that is the maximum dot gain. An excellent offset press can hold a 3 percent dot at either end, but still will have 5-20 percent dot gain. It is important to keep in mind that the minimum dot gain at the ends of the dot range can still be significant. A rule of thumb is that a 20 percent dot gain makes an 80 percent dot go solid. This point shows the relationship between dot gain and dot range. Imposition is the art of laying out the finished pages of a book on the paper they will be printed on. Imposition can be as simple as placing a single page on each side of the output paper, or it can be very complex. For example, offset press impositions may have 16 images on a side in various orientations to accommodate both folding and cutting the printed sheets. The imposition utilized depends on how an operator or user intends to produce the book, including factors such as the final trim size of the book, the size of the paper upon which the book will be printed, the binder utilized, and whether barcodes will be applied to the printed book. When imposing books for Print On Demand applications, an important decision must be made which affects costs. A user can choose impose the books prior to storing them in a Print On Demand repository, or they can be imposed later. Such a decision or test was described earlier, with respect to block 206 of FIG. 2. Imposing the book before storage in a repository is advantageous because when an order arrives for the book and to be printed immediately, the amount of time before printing begins is reduced because time is not wasted actually imposing the book. Imposing the book prior to storage in a repository does have one main disadvantage. Understanding this disadvantage requires some preliminary explanation. Which imposition utilized depends partly on which binder plan is utilized. Binders may be designed to handle particular page image placement, paper fold, and other characteristics. If the same binder is always utilized, the same imposition can always be used. Instances may exist, however, when a different binder is required. For example, more than one binder may be available at the printing facility and one may be in use, broken, or in scheduled maintenance. Alternatively, an expanding business may outgrow existing binders or an existing binder may be worn out. Therefore, it may be necessary to purchase a new binder. In such scenarios, the other binder utilized may not bind correctly for a selected imposition. If a book is imposed prior to storage it in a repository, then valid binding options for that imposed book are limited. Therefore, if at any time more than one kind of binder is utilized in a book manufacturing operation, imposing the book after an order arrives may enable one to more accurately determine which imposition to utilize. FIG. 5 illustrates a schematic diagram of a system 500 of color profile usage in accordance with a preferred embodiment of the present invention. Because of the importance of color in the printing industry, a group of companies referred to as the International Color Consortium® (ICC) have established a standard data format, called an ICC profile, to enable the exchange of characterization data through color imaging and printing workflows. Scanners, monitors and printers do not use exactly the same set of colors. Therefore, colors from a single original can vary significantly when captured or displayed on the different devices. An ICC profile is a data file that maps the set of colors of one device (i.e., capture or print condition) to a standard set of colors that a color management module (such as a color processing software module) can interpret. A color management module (CMM) can utilize a sequence of ICC profiles to map the colors of one device into the colors of any other device. This mapping enables each device to display colors appropriately, so that the colors look the same to the observer as an image moves between devices in a workflow. The process used to build an ICC profile is called characterization. FIG. 5 therefore illustrates a schematic diagram of how ICC color profiles are used. In the diagram, Monitor RGB, Scanner RGB, and Printer CMYK are device-dependent color spaces. CIELAB is a standard, device-independent color space that is used as an intermediary between various device-dependent color spaces (e.g., intermediate color space is known as a Profile Connection Space, or PCS). CIEXYZ is another such PCS color space. An ICC profile maps each possible device-dependent color to a color in the PCS (e.g., LAB or XYZ) color space. Typical use of ICC profiles in a workflow might proceed this way: an image is scanned as Scanner RGB and stored in a TIFF image file that also contains an ICC Scanner RGB Profile. When the image is imported into, for example, a Photoshop 6.0 application, to display the image on the monitor, the Photoshop application can convert the LAB color values produced through the scanner RGB profile into Monitor RGB values by using the XYZ to Monitor RGB map in the Monitor Profile (i.e., Photoshop uses a standard algorithm to convert CIELAB to CIEXYZ). In this way, the monitor can display colors as they were meant to appear in the original scanned image (i.e., albeit within the physical limits of the monitor device color gamut). In addition, any color editing operations the user performs will tend to be accurate since the user will be seeing the color accurately. Such a mapping to display operation does not change the original Scanner RGB of the image. Similarly, when the file is prepared for printing, the LAB color values produced through the Scanner Profile are converted into Printer CMYK values by using the LAB to Printer CMYK map in the Printer Profile. In this manner, the printer can print colors as they were meant to appear in the original scanned image. Characterization creates an ICC profile for a print condition (such as a particular device, paper stock, screening method or paper color). As shown above, when an ICC profile is built for each device in a workflow, the profiles help translate color definitions among the devices so that available colors scanned, displayed or printed appear the same between those devices. Characterization creates a bridge between image input methods and image-printing methods, enabling various printers and Digital Front Ends to correctly reproduce an original image. Performing a characterization operation requires more training than performing a calibration operation therefore it is recommended that a skilled operator perform characterization. Blocks 502, 504 and 506 generally indicate the aforementioned color profile usage operations. FIG. 6 illustrates a high-level flow chart 600 depicting an imposition workflow in accordance with a preferred embodiment of the present invention. As indicated at block 602, electronic data relative to a publication (e.g., a book) can be acquired and set-up preparations implemented via an imposition software application. All high-end imposition applications require users to create templates to define their impositions. A non-limiting example of an imposition software application which can be adapted for use with an embodiment of the present invention is Creo Preps, (i.e., also referred to as “Preps”). Preps is an example of one type of imposition tool utilized in the commercial printing industry that permits a user to impose any combination of, for example, PostScript®, PDF, EPS, DCS, and TIFF source files into signatures, thereby eliminating the need for manual stripping. Such imposed signatures can be output to any PostScript-compatible device such as a CTP device, an image setter, on-demand printer, digital printer, wide format imposition proofer, or a laser printer. Creo Preps is a product of Creo, a company based in Burnaby, British Columbia, Canada. Note that the use of the “Preps” application is not considered a limiting feature of the methods and systems disclosed herein. Rather, such an application is referenced herein for general edification and illustrative purposes only. Following process of the acquisition and imposition software set-up operation depicted at block 604, imposition templates can be created. Thereafter, as indicated at block 606, a book block (e.g., PostScript®, PDF, and the like) can be imported into the imposition software application. Next, as indicated at block 608, a book block image can be imposed utilizing the imposition software application. Thereafter, as illustrated at block 610, the imposed image thereof can be printed to PostScript® and/or exported to PDF format from the imposition software application. Finally, as depicted at block 612, an operation can be performed to check to insure that the resulting imposition was rendered correctly. Generally, the type of imposition required depends on the printing and binding equipment utilized. Imposition procedures displayed in FIG. 6 can be modified for various combinations of equipment. Within the imposition software application, a template (*.tpl) file can define each specific type of imposition. A different template can be required for each final book trim size. The color book solution depicted at block 140 should supply the imposition software templates for all of required sizes and orientations. Such a solution can also provide instructions for customizing and saving new imposition software templates for any size in a supported imposition. Such solutions can include *.tpl files, which have the following naming convention: <imposition type><width>×<height>.tpl. The width and height represent the final trim size of the book and the < > symbols enclose variable information. By convention, the first number (width) always represents the horizontal axis of the finished version of the book and the second number (height) is always the vertical axis of the book. This allows the user to distinguish an imposition template as being for either a landscape or portrait book. The following are examples of the imposition template naming convention: 1Up6×9on85×11.tpl (This represents a 6×9 1-up template on 8.5×11 paper) 2Upfor16×825.tpl (This represents a 6×8.25 2-up-for-1 template) 2Upfor255×85.tpl (This represents a 5.5×8.5 2-up-for-2 template) BF6×9.tpl (This represents a 6×9 Book Factory template) In general, a 1-up imposition means that 1 image is included on each output side (2 images per sheet) and one book is produced from the imposition. Since the final book is also 1-up, the imposition is simply the process of rearranging the images so that they can be printed and bound. FIG. 7 illustrates a schematic diagram 700 that depicts the results of applying a digital book 1-up imposition to a 100-page book in accordance with a preferred embodiment of the present invention. FIG. 7 depicts the first page of a 1-up imposition of a 100-page book. The format is the same as a familiar book: one image (e.g., page 1) on the front of a sheet and the next image (e.g., page 2) with the same size, orientation and registration as the previous page on the back. FIG. 8 illustrates a block diagram depicting the geometry 800 of a 1-up imposition in accordance with a preferred embodiment of the present invention. FIG. 8 generally depicts the 1-up imposition after the transformations have been applied. The areas marked A and Q represent the page image (e.g.,, text, graphics, and margins) at the finished book size. The rectangle surrounding the page images represents the paper the page images will be printed on. A and Q will be on opposite sides of the same printed sheet, in the same orientation, and with the same registration. This imposed image may be printed on a variety of page sizes depending on the application being used. Paper 802 generally indicates the paper the page image is printed upon (e.g., side 1). Page marks 804 and 806 indicate the book's page image. Paper 808 represents the paper the page image is printed on (e.g., side 2). Table 1 below defines the labeled distance parameters in FIG. 8. TABLE 1 Distance Parameters Used in a 1-up Imposition Parameter Definition hb Horizontal bleed. It may be zero. Used if a binder trims the paper. ph The height of the paper the book will be printed on (for example, the total height of the PostScript file declared in the BoundingBox: DSC tag). pw The width of the paper the book will be printed on (for example, the total width of the PostScript file declared in the BoundingBox: DSC tag). bh The height of the final book (final trim size). bw The width of the final book (final trim size). Note that the configurations depicted in FIGS. 7 and 8 represents merely one example of an imposition that can be implemented in accordance embodiments of the present invention. Other imposition configurations are possible and desirable. For example, 2-up imposition embodiments can be implemented in accordance with alternative embodiments of the present invention. Embodiments disclosed herein thus generally describe methods and systems for maintaining color consistency in print-on-demand applications. Initially, a plurality of default color settings applicable to a plurality of print-on-demand operations can be established. Thereafter, color consistency can be selectively imposed across a plurality of print-on-demand operations based on the plurality of default color settings applicable to the plurality of print-on-demand operations. Finally, a print-on-demand media product can be rendered in response to selectively imposing color consistency across the plurality of print-on-demand operations. An end-to-end print-on-demand workflow is therefore disclosed herein that describes how to create and print color books while maintaining color consistent at each step of in the work follow. It can be appreciated that various other alternatives, modifications, variations, improvements, equivalents, or substantial equivalents of the teachings herein that, for example, are or may be presently unforeseen, unappreciated, or subsequently arrived at by applicants or others are also intended to be encompassed by the claims and amendments thereto. | <SOH> BACKGROUND OF THE INVENTION <EOH>Print-on-demand (POD) for books involves the on demand, printing, binding and trimming of bound books. POD is also applicable to other publications and media that require finishing. Typically, bound books comprise a stacked plurality of text pages referred to as a book block, which includes one edge that is known to as the spine. The cover is of a suitable cover stock that is generally thicker and/or heavier than the text pages comprising the book block. The cover has a front portion that overlies the front of the book block, a back portion that overlies the back of the book block, and a center portion spanning across the spine of the book block. A suitable adhesive can be applied between the spine of the book block and the inside face of the center portion of the cover. The spine of the book block (i.e., the edges of the text pages along one edge of the book block) can be imbedded in the adhesive which, upon curing, securely adheres the pages of the book block to one another and to the center portion of the cover, thereby permitting the book to be opened to any page without the pages coming loose. In high volume production processes for manufacturing such bound books, the pages of each book block are usually jogged by specially developed machines prior to the application of adhesive so as to insure that the edges of the pages are properly aligned with one another. The adhesive, typically a suitable hot melt adhesive, is then applied to the spine of the book block. The cover, which is usually pre-printed, is then folded around the front, spine, and back of the book block and is firmly clamped to the book block proximate the spine during assembly. In this manner, the adhesive is firmly pressed between the spine of the book block and the inner face of the center portion of the cover to properly adhere the cover to the book block while simultaneously adhering the pages to one another. Typically, bound books are printed on pages that are somewhat larger than the desired size (i.e., the length and width) of the finished and bound book to be produced. These books, after they are bound, are typically trimmed along three sides to the desired final dimension in a separate trimming machine. Heretofore, such operations were carried out in separate machines that required considerable adjustment to bind books of different sizes and thus were best suited for production runs of many books. In addition, both prior art binding machines and trimming machines were very expensive. In recent years, book printing has undergone changes as computer technology and laser printers have advanced. This new technology now allows for machines capable printing perfect bound books “on-demand”. This new technology is often referred to as print-on-demand (POD). Such POD printed books come in a variety of formats and thicknesses (i.e., the number of pages in the book). Note that the terms “printing-on-demand” and “print-on-demand” are generally utilized interchangeably and refer to the same acronym “POD”. One example of a print-on-demand (POD) system is disclosed in U.S. Pat. No. 5,995,721, “Distributed Printing System,” which issued to Rourke et al. on Nov. 30, 1999. U.S. Pat. No. 5,995,721 generally discloses document processing system including at least one document reproduction apparatus and managing on-demand output of a document job. The document job is characterized by a set of job attributes with each job attribute relating to a manner in which the document job is to be processed by the document processing system. The document processing system, which further includes a document server for managing conversion of the document job into the on-demand output, includes: a plurality of queues mapped to a plurality of document processing subsystems, each of the plurality of queues including a set of queue attributes characterizing the extent to which each document processing subsystem mapped to one or more of the plurality of queues is capable of processing a job portion delivered to the one or more queues. Another example of a print-on-demand system is disclosed U.S. Pat. No. 5,832,193, “Method and apparatus for printing a label on the spine of a bound document,” which issued to Perine et al on Nov. 3, 1998. U.S. Pat. No. 5,832,193 generally describes a printing system for printing a representation of an image on a first portion of a bound document with the image being disposed on a second portion of the bound document is provided. The printing system includes an input station for generating a print job including the image, and a printing machine, communicating with the input station, for producing prints corresponding with the job, wherein one of the prints includes the image as a printed image. The printing system of U.S. Pat. No. 5,832,193 further includes a spine printing apparatus including an image capture system for reading the printed image and converting the same to a set of image data; and a printing device for printing the representation of the image, by reference to the set of image data, on the first portion of the bound document. Note that both U.S. Pat. Nos. 5,995,721 and 5,832,193 are incorporated herein by reference. Note, however, that neither U.S. Pat. Nos. 5,995,721 nor 5,832,193 constitute essential matter. Such patents are referenced herein for general edification and background purposes only. Books and other publications created for print-on-demand (POS) applications can therefore be mastered (i.e., run through a pre-press process), placed in a repository, and then printed, bound and trimmed when an order for the book arrives. One of the primary problems that current POD systems encounter is that color does not remain constant at each step in the workflow. While the industry has produced standards that facilitate consistent color throughout printing and other associated workflow processes, the actual applications have lagged behind in implementing such standards. As a result, the deployment of digital, on-demand printing systems, in addition to the complexity of other technologies has prevented many users from deploying correctly implementing such workflows, at least with respect to color rendering. A need thus exists for improved methods and systems for permitting the deployment of POD systems for color publishing, such as color books. An end-to-end workflow for creating and printing color books while maintaining color consistent at each step in the workflow is needed. | <SOH> BRIEF SUMMARY <EOH>It is, therefore, a feature of the present invention to provide for improved print-on-demand (POD) methods and systems. It is another feature of the present invention to provide for improved color rendering methods and systems. It is also a feature of the present invention to provide for POD methods and systems that incorporate color rendering capabilities. It is additionally a feature of the present invention to provide for an improved POD workflow in which color consistency is maintained through out a POD workflow. Aspects of the present invention relate to methods and systems for maintaining color consistency in print-on-demand applications. Initially, a plurality of default color settings applicable to a plurality of print-on-demand operations can be established. Thereafter, color consistency can be selectively imposed across a plurality of print-on-demand operations based on the plurality of default color settings applicable to the plurality of print-on-demand operations. Finally, a print-on-demand media product can be rendered in response to selectively imposing color consistency across the plurality of print-on-demand operations. An end-to-end print-on-demand workflow is therefore disclosed herein that describes how to create and print color books while maintaining color consistency at each step of in the workflow. | 20040112 | 20070116 | 20050714 | 95014.0 | 0 | NGUYEN, THINH H | METHODS AND SYSTEMS FOR MAINTAINING COLOR CONSISTENCY IN A PRINT-ON-DEMAND WORKFLOW | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,756,444 | ACCEPTED | Method for secure key exchange | Secure key exchange and protected content distribution between a first entity and a second entity in a processing system may be accomplished by generating, by the first entity, a first key, encrypting the first key with a public key of a third entity, and storing the encrypted first key in the third entity. The second entity generates a second key, encrypts the second key with the public key of the third entity, and stores the encrypted second key in the third entity. The third entity decrypts the encrypted first key and the encrypted second key, using the third entity's private key to obtain the first key and the second key, encrypts the first key using the second key, and stores the first key encrypted by the second key in the third entity. The second entity then obtains the first key encrypted by the second key, and decrypts, using the second key, the first key encrypted by the second key. The first key may then be used to encrypt content sent to from the second entity to the first entity. | 1. A method of secure key exchange between a first entity and a second entity comprising: generating, by the first entity, a first key, encrypting the first key with a public key of a third entity, and storing the encrypted first key in the third entity; generating, by the second entity, a second key, encrypting the second key with the public key of the third entity, and storing the encrypted second key in the third entity; decrypting, by the third entity, the encrypted first key and the encrypted second key, using the third entity's private key to obtain the first key and the second key; encrypting, by the third entity, the first key using the second key, and storing the first key encrypted by the second key in the third entity; obtaining, by the second entity, the first key encrypted by the second key, and decrypting, using the second key, the first key encrypted by the second key. 2. The method of claim 1, further comprising encrypting content with the first key by the second entity and transferring the encrypted content from the second entity to the first entity. 3. The method of claim 1, wherein the first entity comprises a graphics device. 4. The method of claim 1, wherein the second entity comprises an application program. 5. The method of claim 1, wherein the third entity comprises a trusted platform module. 6. The method of claim 1, wherein generating the first key comprises pseudorandomly generating the first key, and generating the second key comprises pseudorandomly generating the second key. 7. The method of claim 1, wherein the first key and the second key comprise symmetric keys. 8. The method of claim 1, further comprising signaling the first entity, by the second entity, to start the key exchange. 9. The method of claim 8, wherein signaling comprises storing a value in a register resident in the first entity. 10. A system for secure key exchange comprising: a third entity having a public/private key pair; a first entity to generate a first key, to encrypt the first key with the public key of the third entity, and to store the encrypted first key in the third entity; a second entity to generate a second key, to encrypt the second key with the public key of the third entity, and to store the encrypted second key in the third entity; wherein the third entity decrypts the encrypted first key and the encrypted second key using the third entity's private key to obtain the first key and the second key, encrypts the first key using the second key, and stores the first key encrypted by the second key in the third entity; and wherein the second entity obtains the first key encrypted by the second key from the third entity, and decrypts, using the second key, the first key encrypted by the second key. 11. The system of claim 10, wherein the first entity comprises a graphics device. 12. The system of claim 10, wherein the second entity comprises an application program. 13. The system of claim 10, wherein the third entity comprises a trusted platform module. 14. The system of claim 13, wherein the trusted platform module comprises a first register to store the encrypted first key, a second register to store the encrypted second key, and a third register to store the first key encrypted by the second key. 15. The system of claim 10, wherein the first key and the second key comprise pseudorandomly generated symmetric keys. 16. The system of claim 10, wherein the second entity encrypts content with the first key and transfers the encrypted content to the first device. 17. The system of claim 10, wherein the third entity comprises an input/output pin dedicated for use by the first entity, and the first entity is coupled to the dedicated input/output pin using a buried line on a printed circuit board. 18. A method of secure key exchange and protected content distribution between a graphics device and an application program comprising: pseudorandomly generating, by the graphics device, a first symmetric key, encrypting the first symmetric key with a public key of a trusted platform module (TPM), and storing the encrypted first symmetric key in a first register in the TPM; pseudorandomly generating, by the application program, a second symmetric key, encrypting the second symmetric key with the public key of the TPM, and storing the encrypted second symmetric key in a second register in the TPM; decrypting, by the TPM, the encrypted first symmetric key and the encrypted second symmetric key using the TPM's private key to obtain the first symmetric key and the second symmetric key; encrypting, by the TPM, the first symmetric key using the second symmetric key, and storing the first symmetric key encrypted by the second symmetric key in a third register in the TPM; obtaining, by the application program, the first symmetric key encrypted by the second symmetric key from the third register, and decrypting, using the second symmetric key, the first symmetric key encrypted by the second symmetric key; and encrypting content, by the application program, using the first symmetric key, and sending the encrypted content to the graphics device. 19. The method of claim 18, further comprising signaling the graphics device, by the application program, to start the key exchange. 20. The method of claim 19, wherein signaling comprises storing a value in a register resident in the graphics device. 21. The method of claim 18, further comprising, decrypting, by the graphics device, the encrypted content using the first symmetric key. | BACKGROUND 1. Field The present invention relates generally to computer security and, more specifically, to exchanging cryptographic keys in a processing system. 2. Description One of the hurdles in providing protected digital content on a computing platform (such as the personal computer (PC)) is that the application program that is extracting the protected content and the graphics device that is decoding and/or displaying the content need to agree on a cryptographic key to encrypt the data exchange between them. If the content is not encrypted during transfer between the application and the graphics device, the content may be vulnerable to interception. One of the two entities cannot merely generate the key and send the key to the other entity because there is typically no “non-snoopable” secure path between the application and the graphics device. One approach to this problem is to embed identical encryption keys in the graphics device and the application, and then use this key. This approach entirely avoids the key exchange. However, this solution is not robust because the application program may be hacked to discover the key. Another approach is to embed a private key of a public/private key pair in the graphics device and send the corresponding public key to the application. The application then uses the public key to encrypt the content and the graphics device uses the private key to decrypt the content. Alternatively, the application can generate a new symmetric session key, encrypt it with the graphic device's public key, and send it to the graphics device (hence the public-private key pair is used to enable exchange of the symmetric key). Since by definition the public key does not need to be protected from other agents, the public key can be sent to the application in the clear. Both of these approaches require a key to be embedded in the graphics device. This increases the manufacturing cost and adds complexity to the manufacturing flow for graphics devices. A better approach is needed. BRIEF DESCRIPTION OF THE DRAWINGS The features and advantages of the present invention will become apparent from the following detailed description of the present invention in which: FIG. 1 is a diagram illustrating a processing system having a trusted platform module (TPM) according to an embodiment of the present invention; FIG. 2 is a flow diagram illustrating a process for secure key exchange according to an embodiment of the present invention; and FIG. 3 is a diagram illustrating communications between an application, a graphics device and a TPM according to an embodiment of the present invention. DETAILED DESCRIPTION An embodiment of the present invention is a method of exchanging a cryptographic key between two entities within a processing system. In one embodiment, the two entities may be an application program and a graphics device. However, embodiments of the present invention may be used with any two entities in a processing system. Embodiments of the present invention make use of a trusted platform module (TPM), which is used as a root of trust for a processing system. Every TPM contains a public/private key pair. Embodiments of the present invention leverage the TPM's key pair to facilitate the key exchange. The present invention does not require any keys to be embedded in the entities that need to agree on a common key. Reference in the specification to “one embodiment” or “an embodiment” of the present invention means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrase “in one embodiment” appearing in various places throughout the specification are not necessarily all referring to the same embodiment. An exemplary processing system for embodiments of the present invention is shown in FIG. 1, however, other systems may also be used and not all components of the processing system shown are required for the present invention. Sample system 100 may be used, for example, to execute the processing for embodiments of the present invention. Sample system 100 is representative of processing systems based on the PENTIUM® family of processors and CELERON™ processors available from Intel Corporation, although other systems (including personal computers (PCs) or servers having other processors, engineering workstations, other set-top boxes, and the like) and architectures may also be used. FIG. 1 is a block diagram of a system 100 of one embodiment of the present invention. The system 100 includes a processor 102 that processes data signals. Processor 102 may be coupled to a processor bus 104 that transmits data signals between processor 102 and other components in the system 100. System 100 includes a memory 106. Memory 106 may store instructions and/or data represented by data signals that may be executed by processor 102. The instructions and/or data may comprise code for performing any and/or all of the techniques of the present invention. Memory 106 may also contain additional software and/or data such as at least one application program 107. A bridge/memory controller 110 may be coupled to the processor bus 104 and memory 106. The bridge/memory controller 110 directs data signals between processor 102, memory 106, and other components in the system 100 and bridges the data signals between processor bus 104, memory 106, and a first input/output (I/O) bus 112. In this embodiment, graphics device 113 interfaces to a display device (not shown) for displaying images rendered or otherwise processed by the graphics device 113 to a user. Graphics device 113 may comprise a start key exchange register 115. The graphics device may receive data such as protected digital content from the application when the application is being executed by the processor. First I/O bus 112 may comprise a single bus or a combination of multiple buses. First I/O bus 112 provides communication links between components in system 100. In at least one embodiment, a trusted platform module (TPM) 116 may be coupled to bus bridge 126. A TPM comprises circuitry included within a processing system to support trusted computing. A TPM has been defined by the Trusted Computing Group (TCG) in the Trusted Computing Platform Association (TCPA) Main Specification 1.2, February 2002, and successive versions, available from the TCG. A TPM operates somewhat like a “smart card” on a motherboard of a computer system (such as a personal computer (PC)), to provide various security functions to the system. There is only one TPM per system. The TPM includes at least one public/private key pair for use in cryptographic operations, can generate anonymous key pairs for use by other entities within the system, can perform encryption and decryption operations, can sign and verify data, and can establish a root of trust for the system. The TPM is considered to be difficult to break into and affect its operations. In at least one embodiment, TPM 116 comprises at least three registers, denoted register A 117, register B 118, and register C 119, herein. Embodiments of the present invention use the TPM's key infrastructure and these three registers to perform a key exchange. A second I/O bus 120 may comprise a single bus or a combination of multiple buses. The second I/O bus 120 provides communication links between components in system 100. A data storage device 122 may be coupled to the second I/O bus 120. A keyboard interface 124 may be coupled to the second I/O bus 120. A user input interface 125 may be coupled to the second I/O bus 120. The user input interface may be coupled to a user input device, such as a remote control, mouse, joystick, or trackball, for example, to provide input data to the system. A bus bridge 126 couples first I/O bridge 112 to second I/O bridge 120. Embodiments of the present invention are related to the use of the system 100 as a component in a content protection and rendering system. According to one embodiment, such processing may be performed by the system 100 in response to processor 102 executing sequences of instructions in memory 106. Such instructions may be read into memory 106 from another computer-readable medium, such as data storage device 122, for example. Execution of the sequences of instructions causes processor 102 to execute secure key exchange processing for the application according to embodiments of the present invention. In an alternative embodiment, hardware circuitry may be used in place of or in combination with software instructions to implement portions of embodiments of the present invention. Thus, the present invention is not limited to any specific combination of hardware circuitry and software. The elements of system 100 perform their conventional functions in a manner well-known in the art. In particular, data storage device 122 may be used to provide long-term storage for the executable instructions and data structures for embodiments of components of the content distribution system in accordance with the present invention, whereas memory 106 is used to store on a shorter term basis the executable instructions of embodiments of components of the content distribution system in accordance with the present invention during execution by processor 102. FIG. 2 is a flow diagram illustrating a process for secure key exchange between entities in a processing system according to an embodiment of the present invention. At block 200, a first entity in the processing system, such as application program 107 for example (which in some embodiments may comprise a content player application) signals a second entity, such as graphics device 113, to start key exchange processing. The key exchange may be needed to support protected transmission of content from the first entity to the second entity. In one embodiment, the second entity comprises a hardware device (such as a graphics controller/graphics card/graphics device) having a register that, when written to, indicates a request to start key exchange processing between the hardware device and another entity in the processing system. In one embodiment, this register may be known as a start key exchange register 115, and the first entity (e.g., the application) causes the writing of a predetermined value into the start key exchange register to start key exchange processing. The writing of the start key exchange register is represented as flow 300 on FIG. 3. In other embodiments, other methods of signaling the graphics device to start the key exchange may be used. At block 202, after detecting the writing of the start key exchange register, the graphics device generates a first pseudorandom symmetric key KD using any well known method of key generation. The TPM comprises at least one public/private key pair. The TPM's public key is known by other entities in the processing system. At block 204, the graphics device encrypts the pseudorandomly generated key KD using the TPM's public key KTPM-PUB according to well known methods of public key cryptography to form a first encrypted value E(KD, KTPM-PUB). At block 206, the graphics device sends the first encrypted value E(KD, KTPM-PUB) to TPM 116 and causes the writing of the first encrypted value E(KD, KTPM-PUB) into a first register, such as Register A 117. This action is represented as flow 302 on FIG. 3. Since the TPM's public key was used to encrypt the graphic device's key, only the TPM's corresponding private key can be used to decrypt the graphic device's key. Next, at block 208, the application generates a second pseudorandom symmetric key KA using any well known method of key generation. At block 210, the application encrypts the pseudorandomly generated key KA using the TPM's public key KTPM-PUB according to well known methods of public key cryptography to form a second encrypted value E(KA, KTPM-PUB). At block 212, the application sends the second encrypted value E(KA, KTPM-PUB) to TPM 116 and causes the writing of the second encrypted value E(KA, KTPM-PUB) into a second register, such as Register B 118. This action is represented as flow 304 on FIG. 3. Since the TPM's public key was used to encrypt the application's key, only the TPM's corresponding private key can be used to decrypt the application's key. In one embodiment, blocks 208 to 212 may be performed concurrently with blocks 200 to 206. At block 214, the TPM decrypts the first and second encrypted values stored in register A and register B, respectively, using the TPM's private key KTPM-PRI. The TPM now has both the application's key KA and the graphic device's key KD. Since the TPM is very difficult to access in an unauthorized way, these values are considered to be secure. Next, at block 216, the TPM encrypts the graphic device's symmetric key KD using the application's symmetric key KA and an appropriate encryption algorithm, and stores the third encrypted value E(KD, KA) into a third register in the TPM, such as register C 119. At block 216, the application reads the contents of register C 119 from the TPM to obtain the third encrypted value E(KD, KA). This action is represented as flow 306 in FIG. 3. The capability for the application to obtain the contents of register C from the TPM is assumed in this embodiment. At block 218, the application decrypts the contents of register C received from the TPM using the application's own key KA and a corresponding decryption algorithm to obtain KD. Since all of the data flows between entities as shown in FIG. 3 were encrypted, the data may be secure against hackers attempting to discover the keys by monitoring communications between the entities. The graphic device's symmetric key KD may now be used by the application to encrypt content. The encrypted content may be sent by the application to the graphics device, where the encrypted content may be decrypted by the graphics device and further processed (e.g., rendered for perception by the user), since the graphics device already knows its own key KD. In one embodiment, if the graphics device needed to know the application's key KA, a similar mechanism to blocks 216 to 220 may be used to transfer the application's key to the graphics device in a protected manner. In the above embodiments, for good security the application needs to ensure that the key exchange happened with a legitimate graphics device and not a hacker's unauthorized device masquerading as the graphics device. This can be ensured by providing a private path from the graphics device to a dedicated TPM graphics processor input/output (I/O) (GPIO) pin. This path would ensure that Register A 117 would be written only with data received over the line connected to the GPIO pin to the TPM. The GPIO pin may be connected to the graphics device (e.g., an advanced graphics processor (AGP)/peripheral component interconnect (PCI) slot) using a buried line on the printed circuit board of the processing system's motherboard that is not easily detectable by a hacker. This line is also represented as flow 302 on FIG. 3. In the absence of embedded keys in the endpoints of the exchange, if two endpoints want to agree on a common key it typically requires a fairly elaborate and complex protocol (e.g., Diffie-Hellman key exchange). One simple solution is to embed keys in the endpoints and then use the embedded key to encrypt the key that needs to be exchanged. However, embedding keys in the endpoints adds a lot of security overhead because the keys have to be protected. Additionally, embedded keys raises revocation issues for devices. If the keys need to be unique, then this adds to the manufacturing complexity and cost. In contrast, embodiments of the present invention allow a secure key exchange to take place between two entities (e.g., an application program and a graphics device) without either of them embedding any keys. The entities take advantage of the public/private key pair that is available on the platform in the TPM to perform the key exchange in a secure manner. In the preceding description, various aspects of the present invention have been described. For purposes of explanation, specific numbers, systems and configurations were set forth in order to provide a thorough understanding of the present invention. However, it is apparent to one skilled in the art having the benefit of this disclosure that the present invention may be practiced without the specific details. In other instances, well-known features were omitted or simplified in order not to obscure the present invention. Embodiments of the present invention may be implemented in hardware or software, or a combination of both. However, embodiments of the invention may be implemented as computer programs executing on programmable systems comprising at least one processor, a data storage system (including volatile and non-volatile memory and/or storage elements), at least one input device, and at least one output device. Program code may be applied to input data to perform the functions described herein and generate output information. The output information may be applied to one or more output devices, in known fashion. For purposes of this application, a processing system embodying the portions of the present invention includes any system that has a processor, such as, for example, a digital signal processor (DSP), a microcontroller, an application specific integrated circuit (ASIC), or a microprocessor. The programs may be implemented in a high level procedural or object oriented programming language to communicate with a processing system. The programs may also be implemented in assembly or machine language, if desired. In fact, the invention is not limited in scope to any particular programming language. In any case, the language may be a compiled or interpreted language. The programs may be stored on a removable storage media or device (e.g., floppy disk drive, read only memory (ROM), CD-ROM device, flash memory device, digital versatile disk (DVD), or other storage device) readable by a general or special purpose programmable processing system, for configuring and operating the processing system when the storage media or device is read by the processing system to perform the procedures described herein. Embodiments of the invention may also be considered to be implemented as a machine-readable storage medium, configured for use with a processing system, where the storage medium so configured causes the processing system to operate in a specific and predefined manner to perform the functions described herein. Although the operations describe herein may be described as a sequential process, some of the operations may in fact be performed in parallel or concurrently. In addition, in some embodiments the order of the operations may be rearranged without departing from the spirit of the invention. The techniques described herein are not limited to any particular hardware or software configuration; they may find applicability in any computing or processing environment. The techniques may be implemented in hardware, software, or a combination of the two. The techniques may be implemented in programs executing on programmable machines such as mobile or stationary computers, personal digital assistants, set top boxes, cellular telephones and pagers, and other electronic devices, that each include a processor, a storage medium readable by the processor (including volatile and non-volatile memory and/or storage elements), at least one input device, and one or more output devices. Program code is applied to the data entered using the input device to perform the functions described and to generate output information. The output information may be applied to one or more output devices. One of ordinary skill in the art may appreciate that the invention can be practiced with various computer system configurations, including multiprocessor systems, minicomputers, mainframe computers, and the like. The invention can also be practiced in distributed computing environments where tasks may be performed by remote processing devices that are linked through a communications network. Each program may be implemented in a high level procedural or object oriented programming language to communicate with a processing system. However, programs may be implemented in assembly or machine language, if desired. In any case, the language may be compiled or interpreted. Program instructions may be used to cause a general-purpose or special-purpose processing system that is programmed with the instructions to perform the operations described herein. Alternatively, the operations may be performed by specific hardware components that contain hardwired logic for performing the operations, or by any combination of programmed computer components and custom hardware components. The methods described herein may be provided as a computer program product that may include a machine readable medium having stored thereon instructions that may be used to program a processing system or other electronic device to perform the methods. The term “machine readable medium” used herein shall include any medium that is capable of storing or encoding a sequence of instructions for execution by the machine and that cause the machine to perform any one of the methods described herein. The term “machine readable medium” shall accordingly include, but not be limited to, solid-state memories, optical and magnetic disks, and a carrier wave that encodes a data signal. Furthermore, it is common in the art to speak of software, in one form or another (e.g., program, procedure, process, application, module, logic, and so on) as taking an action or causing a result. Such expressions are merely a shorthand way of stating the execution of the software by a processing system cause the processor to perform an action of produce a result. While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications of the illustrative embodiments, as well as other embodiments of the invention, which are apparent to persons skilled in the art to which the invention pertains are deemed to lie within the spirit and scope of the invention. | <SOH> BACKGROUND <EOH>1. Field The present invention relates generally to computer security and, more specifically, to exchanging cryptographic keys in a processing system. 2. Description One of the hurdles in providing protected digital content on a computing platform (such as the personal computer (PC)) is that the application program that is extracting the protected content and the graphics device that is decoding and/or displaying the content need to agree on a cryptographic key to encrypt the data exchange between them. If the content is not encrypted during transfer between the application and the graphics device, the content may be vulnerable to interception. One of the two entities cannot merely generate the key and send the key to the other entity because there is typically no “non-snoopable” secure path between the application and the graphics device. One approach to this problem is to embed identical encryption keys in the graphics device and the application, and then use this key. This approach entirely avoids the key exchange. However, this solution is not robust because the application program may be hacked to discover the key. Another approach is to embed a private key of a public/private key pair in the graphics device and send the corresponding public key to the application. The application then uses the public key to encrypt the content and the graphics device uses the private key to decrypt the content. Alternatively, the application can generate a new symmetric session key, encrypt it with the graphic device's public key, and send it to the graphics device (hence the public-private key pair is used to enable exchange of the symmetric key). Since by definition the public key does not need to be protected from other agents, the public key can be sent to the application in the clear. Both of these approaches require a key to be embedded in the graphics device. This increases the manufacturing cost and adds complexity to the manufacturing flow for graphics devices. A better approach is needed. | <SOH> BRIEF DESCRIPTION OF THE DRAWINGS <EOH>The features and advantages of the present invention will become apparent from the following detailed description of the present invention in which: FIG. 1 is a diagram illustrating a processing system having a trusted platform module (TPM) according to an embodiment of the present invention; FIG. 2 is a flow diagram illustrating a process for secure key exchange according to an embodiment of the present invention; and FIG. 3 is a diagram illustrating communications between an application, a graphics device and a TPM according to an embodiment of the present invention. detailed-description description="Detailed Description" end="lead"? | 20040112 | 20091222 | 20050714 | 80822.0 | 0 | PERUNGAVOOR, VENKATANARAY | METHOD FOR SECURE KEY EXCHANGE | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,756,538 | ACCEPTED | Method and apparatus for the prevention of critical process variable excursions in one or more turbomachines | Many variables in processes such as those using turbocompressors and turbines must be limited or constrained. Limit control loops are provided for the purpose of limiting these variables. By using a combination of closed loop and open loop limit control schemes, excursions into unfavorable operation can be more effectively avoided. Transition between open loop and closed loop may be enhanced by testing the direction and magnitude of the rate at which the limit variable is changing. If the rate of change indicates recovery is imminent, control is passed back to the closed loop limit control function. | 1. A method for providing limit control, not antisurge control, of a compression process comprising at least one turbocompressor having a limit variable, L, values of said limit variable being divided into a first region wherein closed loop limit control is used and a second region in which open loop limit control is used, the method comprising the steps of: (a) determining the value of the limit variable, L, based on parameters associated with the compression process; (b) calculating a value of a first temporal derivative, dL/dt, of the limit variable, L; (c) providing closed loop limit control when the value of the limit variable, L, is in the first region; (d) calculating an open loop limit control set point based on the value of the first temporal derivative, dL/dt; and (e) providing open loop limit control when the value of the limit variable, L, is in the second region. 2. The method of claim 1 wherein control is returned to closed loop control when the value of a limit variable, L, returns in the first region. 3. The method of claim 1 wherein the step of providing open loop limit control is effected by changing a value of a manipulated variable as quickly as possible a predetermined increment. 4. The method of claim 3 wherein the predetermined increment is variable during operation. 5. The method of claim 4 wherein the predetermined increment is a function of the first temporal derivative, dL/dt, of the limit variable, L. 6. The method of claim 1 wherein the limit variable, L, is a suction pressure of the turbocompressor. 7. The method of claim 1 wherein the limit variable, L, is a discharge pressure of the turbocompressor. 8. The method of claim 1 wherein the turbocompressor comprises a plurality of stages and the limit variable, L, is an interstage pressure of the turbocompressor. 9. A method for providing limit control, not overspeed control, of a turbine selected from the group consisting of a steam turbine and a gas turbine, said turbine having a limit variable, L, values of said limit variable being divided into a first region wherein closed loop limit control is used and a second region in which open loop limit control is used, the method comprising the steps of: (a) calculating the value of the limit variable, L, based on parameters associated with the turbine; (b) calculating a value of a first temporal derivative, dL/dt, of the limit variable, L; (c) providing closed loop limit control when the value of the limit variable, L, is in the first region; (d) calculating an open loop limit control set point based on the value of the first temporal derivative, dL/dt; and (e) providing open loop limit control when the value of the limit variable, L, is in the second region. 10. The method of claim 9 wherein the limit variable, L, is an exhaust gas temperature of a gas turbine and the open loop limit control comprises closing a fuel valve as quickly as possible. 11. The method of claim 9 wherein the limit variable, L, is a discharge steam temperature of a steam turbine and the open loop limit control comprises opening a steam valve as quickly as possible. 12. A method for providing limit control of a process having a limit variable, L, values of said limit variable being divided into a first region wherein closed loop limit control is used and a second region in which open loop limit control is used, the method comprising the steps of: (a) providing open loop limit control when the value of a limit variable, L, is in the second region; (b) calculating a value of a first temporal derivative, dL/dt, of the limit variable, L; and (c) providing closed loop limit control if the value of the first temporal derivative, dL/dt, has a sign indicating the value of L is changing toward the first region. 13. The method of claim 12 wherein the values of the limit variable, L, are divided into three regions: a first region wherein closed loop limit control is used and a second region in which open loop limit control is used, and a third region wherein no limit control is required, the method comprising the additional steps of: (a) setting a closed loop limit control set point in a neighborhood of a boundary between the first and third regions; (b) setting an open loop limit control set point toward the second region relative to the closed loop limit control set point; and (c) providing open loop limit control when a value of a limit variable, L, is at the open loop limit control set point or on an opposite side of the open loop limit control set point relative to the closed loop limit control set point. 14. The method of claim 12 wherein a magnitude of dL/dt is also tested before providing closed loop limit control. 15. The method of claim 12 wherein L must achieve a predetermined value before providing closed loop limit control. 16. The method of claim 12 wherein a closed loop limit control set point is determined as a function of dL/dt. 17. The method of claim 12 wherein an open loop limit control set point is determined as a function of dL/dt. 18. The method of claim 16 wherein the closed loop limit control set point is bounded. 19. The method of claim 17 wherein the open loop limit control set point is bounded. 20. The method of claim 16 wherein a rate of change of the closed loop limit control set point is bounded. 21. The method of claim 17 wherein a rate of change of the open loop limit control set point is bounded. 22. The method of claim 12 wherein the process is a compression process including turbocompressors. 23. The method of claim 12 wherein the process comprises a turbine driver. 24. The method of claim 12 wherein the process comprises an electric motor driver. 25. The method of claim 12 wherein an open loop control action comprises the steps of: (a) determining if open loop control is required based on a value of L; and (b) adjusting a manipulated variable as quickly as possible by a predetermined increment. 26. The method of claim 25 wherein the predetermined increment by which the manipulated variable is adjusted is calculated as a function of the value of the first temporal derivative, dL/dt. 27. An apparatus for providing limit control, not antisurge control, of a compression process having a limit variable, L, values of said limit variable being divided into a first region wherein closed loop limit control is used and a second region in which open loop limit control is used, the apparatus comprising: (a) a calculating function for calculating the value of the limit variable, L, based on parameters associated with a turbocompressor; (b) a closed loop limit controller in effect when the value of the limit variable, L, is in the first region; and (c) an open loop limit controller in effect when the value of the limit variable, L, is in the second region. 28. The apparatus of claim 27 including means to return control to the closed loop controller when the value of a limit variable, L, returns in the first region. 29. The apparatus of claim 27 wherein the step of providing open loop limit control is effected by changing a value of a manipulated variable as quickly as possible a predetermined increment. 30. The apparatus of claim 29 including a calculator for determining a variable predetermined increment during operation. 31. The apparatus of claim 27 including a suction pressure sensor for sensing a suction pressure of the turbocompressor as the limit variable, L. 32. The apparatus of claim 27 including a discharge pressure sensor for sensing a discharge pressure of the turbocompressor as the limit variable, L. 33. The apparatus of claim 27 wherein the turbocompressor comprises a plurality of stages and the apparatus additionally comprises an interstage pressure sensor for sensing an interstage pressure of the turbocompressor as the limit variable, L. 34. An apparatus for providing limit control, not overspeed control, of a turbine selected from the group consisting of a steam turbine and a gas turbine, said turbine having a limit variable, L, values of said limit variable being divided into a first region wherein closed loop limit control is used and a second region in which open loop limit control is used, the apparatus comprising: (a) a calculating function for calculating the value of the limit variable, L, based on parameters associated with a turbocompressor; (b) a closed loop limit controller in effect when the value of the limit variable, L, is in the first region; and (c) an open loop limit controller in effect when the value of the limit variable, L, is in the second region. 35. The apparatus of claim 34 additionally comprising: (a) an exhaust gas temperature sensor for sensing a gas turbine's exhaust gas temperature as the limit variable, L; and (b) a fuel valve, wherein the open loop limit control comprises closing said fuel valve as quickly as possible. 36. The apparatus of claim 34 additionally comprising: (a) a discharge steam temperature sensor for sensing a discharge steam temperature as the limit variable, L; and (b) a steam valve, wherein the open loop limit control comprises opening the steam valve as quickly as possible. 37. A apparatus for providing limit control of a process having a limit variable, L, values of said limit variable being divided into a first region wherein closed loop limit control is used and a second region in which open loop limit control is used, the apparatus comprising: (a) an open loop limit controller, in effect when the value of a limit variable, L, is in the second region; (b) a calculating function for calculating a value of a first temporal derivative, dL/dt, of the limit variable, L; and (c) a closed loop limit controller in effect if the value of the first temporal derivative, dL/dt, has a sign indicating the value of L is changing toward the first region. 38. The apparatus of claim 37 wherein the values of the limit variable, L, are divided into three regions: a first region wherein closed loop limit control is used and a second region in which open loop limit control is used, and a third region wherein no limit control is required, the apparatus additionally comprising: (a) means for setting a closed loop limit control set point in a neighborhood of a boundary between the first and third regions; (b) means for setting an open loop limit control set point toward the second region relative to the closed loop limit control set point; and (c) an open loop limit controller in effect when a value of a limit variable, L, is at the open loop limit control set point or on an opposite side of the open loop limit control set point relative to the closed loop limit control set point. 39. The apparatus of claim 37 additionally comprising a comparator for testing a magnitude of dL/dt before providing closed loop limit control. 40. The apparatus of claim 37 additionally comprising a function calculator for determining the closed loop limit control set point as a function of dL/dt. 41. The apparatus of claim 37 additionally comprising a function calculator for determining the open loop limit control set point as a function of dL/dt. 42. The apparatus of claim 39 additionally comprising a logic function for bounding the closed loop limit control set point. 43. The apparatus of claim 40 additionally comprising a logic function for bounding the open loop limit control set point. 44. The apparatus of claim 37 additionally comprising a manipulated variable, M, adjusted to control the value of the limit variable, L. 45. The method of claim 1 wherein a closed loop limit control set point is determined as a function of dL/dt. | CROSS REFERENCE TO RELATED APPLICATIONS Not applicable. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT Not applicable. REFERENCE TO MICROFICHE APPENDIX Not applicable. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to a control scheme. More particularly the present invention relates to a method and apparatus for more accurately and stably limiting critical variables associated with a process such as those including turbomachines such as a turbocompressor, steam turbine, gas turbine, or expander. 2. Background Art The safe operating regime of a turbocompressor is constrained by the machinery and process limitations. A turbine-driven turbocompressor is generally bound by upper and lower limits of a turbine operating speed, a surge line, a choke limit, high discharge or low suction pressure bounds, and/or a power rating of the turbine. Limit control is used to keep the turbocompressor from entering an operating regime that is not considered safe, is unacceptable from a process standpoint, or undesirable for any reason. Limit control, also referred to as constraint control, is defined as a control strategy that will take action to avoid operating in these undesirable operating regimes, but only takes action when there is a tendency or danger of operating therein. Take, for example, a turbocompressor's discharge pressure that is to be constrained to remain at or below a set point, psp. When the turbocompressor's discharge pressure is below psp, no particular action is taken by the limit control system to adjust psp. Only when the turbocompressor's discharge pressure reaches or exceeds psp is control action taken. Limit control strategies differ from ordinary control strategies in that: ordinary control strategies take measures to keep the process variable at its set point at all times (generally speaking), keeping the process variable from dropping below its set point as well as keeping it from exceeding its set point; limit control strategies are brought to bear only when a limit variable crosses its set point. On one side of its set point, the limit control scheme is not in effect. Often, a rigid limit set point exists where a safety system, associated with the machinery or process, causes the machinery to shut down, or a relief valve to open, etc. The process control system, on the other hand, makes use of soft set points. A soft set point is separated from its associated rigid set point by a safety margin. Minimization of the safety margins results in an expanded operating envelope. Advanced antisurge control systems have been applied very successfully in many applications to prevent the turbocompressor from damages due to surge. In U.S. Pat. No. 4,949,276, a method of antisurge control is disclosed using a speed of approach to surge to increase the safety margin. Once the compressor's operating point has reached the controller's surge control line, closed loop control attempts to prohibit surge by opening an antisurge valve. Open loop control is disclosed in U.S. Pat. Nos. 4,142,838 and 4,486,142. Here, an open loop control line is located toward surge from the surge control line. If closed loop control is unable to keep the compressor's operating point from reaching this open loop control line, an open loop control action will cause the antisurge valve to open as quickly as possible a predetermined increment. A scheme similar to that just described for antisurge control was patented in U.S. Pat. No. 5,609,465 for overspeed control in turbines. Here, a steam valve is closed a predetermined increment as quickly as possible by an open loop control action. Such advanced control schemes have not been applied for other constraints imposed on turbomachinery. Surge and overspeed are known to cause process upsets, but are somewhat unique in their ability to cause damage and destruction to the turbomachinery and adjacent equipment, and even to be dangerous to personnel. In the past, there was no motivation to apply these advanced techniques, along with their complexity, to other constrain control problems. In fact, common understanding taught that an open loop action would cause process upsets, thereby teaching away from the use of these advanced control schemes that resulted in what were considered severe reactions to process events causing a control action. Recently however, competitive conditions and political-economic-environmental issues such as the restriction on carbon dioxide emissions have resulted in reconsidering control strategies to squeeze the last percentage of efficiency from processes, and expand the operating envelope of the process as much as possible. For instance, because of a process upset or a change in operating conditions, a turbocompressor's suction pressure may drop below atmospheric pressure, a condition that can cause air to be entrained in a hydrocarbon being compressed. Or the turbocompressor's interstage pressure may exceed a maximum pressure rating for the machinery casing or process vessels. Present-day control systems typically utilize a secondary-variable closed-loop control scheme to constrain the turbomachine's operating point within predetermined bounds. When a limit-control variable reaches its set point, control is bumplessly transferred from primary variable control to secondary variable limit control and the manipulated variable of the turbomachine is adjusted to bring and/or keep the offending limit-control variable within acceptable limits. Due to excessive dead times or large time constants in the overall system, traditional PID based constraint control actions may sometimes be inadequate to prevent an excursion of a critical process variable into a restricted region caused by a process upset. Moreover the set points configured for limit control are fixed. Therefore, limit control is initiated only if a variable crosses its predetermined limit, that is, a measurable error is incurred. Increasing the gains of the controller may not mitigate the problem due to the overall system's sluggishness (long dead times or large time constants). The best solution to this situation is to configure the control system with conservative safety margins. This invariably contracts the available operating zone of the turbocompressor. The consequence of such a control approach is a decrease in the turbocompressor's throughput with its associated significant impact on plant production. There is, therefore, a need for a limit-control strategy that effectively and stably results in the constraining of limited variables, while bumplessly transferring between primary variable control and constraint variable control. BRIEF SUMMARY OF THE INVENTION A purpose of this invention is to provide a method and apparatus for limiting or constraining critical variables, herein referred to, generically, as “L,” associated with a turbocompressor. Another purpose is to initiate limit-control action such that a limited variable does not cross its base set point. Still another purpose of the present invention is to carry out limit control and the transfer between primary variable control and limit control smoothly and stably. Using a combination of closed loop and open loop responses, the limit-control action is designed to minimize the excursion of critical variables, L, related to a turbocompressor, turbine, expander or its associated process, beyond their set points. Some examples of critical limit (constraint) variables, L, are turbocompressor suction, interstage, and discharge pressures, gas turbine exhaust gas temperature, gas and steam turbine power, machinery rotational speed, and various process pressures and temperatures. Antisurge control is, inherently, limit control, with the limit variable being a measure of a proximity to surge. Fixing the set point for constraint control action can increase the overall response time of the control system. To circumvent this problem, the set point of the constraint-control loop is dynamically adjusted as a function of measurable process disturbances. Care must be taken to ensure that dynamic adjustment to the set point does not result in premature control actions on the manipulated variable (herein generically referred to as “M”) that negatively influence the process. In a preferred embodiment, dynamic correction to the set point of each critical limit variable, L, is made as a function of the first derivative with respect to time, dL/dt, of that critical limit variable. In addition, these set point adjustments are rate limited and bound within acceptable levels in each direction (that is, increasing or decreasing) with the ability to configure independent rates and bounds as required. An additional aspect of the present invention involves a fast acting, open loop, control response in the event the closed loop constraint control proves inadequate. An acceptable threshold of overshoot of a critical process variable measured from its defined constraint control set point is used as an indication of the effectiveness of closed loop action. Once the constrained variable has reached this overshoot threshold, a rapid change in the manipulated variable, M, is initiated to bring the constrained variable back to an acceptable value. This rapid alteration of the manipulated variable, M, is known as an “open loop” response. Specific methods of open-loop control action include a configurable step response, or fast ramp output to the manipulated variable. The open-loop output is adjusted for system dead time or hysteresis. The open loop control response may be repeated with appropriate pause between repetitions as needed to bring the operating point out of an undesirable state. An additional indication of the effectiveness of closed loop action is to identify if a magnitude of a first temporal derivative of a critical process variable exceeds a configurable threshold. Once the open-loop control response is found to be effective, the constraint-control action transitions over to closed loop control in a bumpless manner. A criterion such as a value of the critical process variable compared to its limit set point may be used to determine the point of switchover from open loop action to closed loop control. It is important to ensure that the switchover from open loop action to closed loop control not result in oscillations of the overall system as observed with traditional control systems. Such traditional systems typically employ high gains for constraint control action. In the preferred embodiment of this invention, this is realized by modifying the response of the open loop or closed loop in the return direction. It is important to limit the suction pressure of turbocompressors handling explosive gases. Suction pressure limit-control applications of the present invention include: cracked gas turbocompressors in Ethylene plants, propylene or ethylene refrigeration turbocompressors in gas processing and Olefins plants, propane refrigeration compressors in LNG processes, wet gas compressors in Refineries, and Ammonia refrigeration compressors in fertilizer plants. Interstage pressures may require limiting due to limitations on the machinery casing, or intercoolers or vessels located between stages. Applications for interstage pressure limit control are: fluidized catalytic cracking applications, cracked gas turbocompressors in Ethylene plants, pipe line gas turbocompressors, refrigeration turbocompressors in gas processing, and the turbocompressors used in LNG plants and Ammonia plants. Turbocompressor discharge pressure may require limiting as well due to machinery casing or discharge process component limitations. As mentioned above, there are two types of limit set points spoken of in process control. A rigid limit set point exists where a safety system, associated with the machinery or process, causes the machinery to shut down, or a relief valve to open, etc. The process control system, on the other hand, makes use of soft set points. A soft set point is separated from its associated rigid set point by a safety margin. In this application, only soft set points are of interest. The novel features which are believed to be characteristic of this invention, both as to its organization and method of operation together with further objectives and advantages thereto, will be better understood from the following description considered in connection with the accompanying drawings in which a presently preferred embodiment of the invention is illustrated by way of example. It is to be expressly understood however, that the drawings are for the purpose of illustration and description only and not intended as a definition of the limits of the invention. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS FIG. 1 shows a representative compression system and instrumentation. FIG. 2 shows a turbine driven turbocompressor with instrumentation and a control system. FIG. 3 shows a flow diagram of the present invention. FIG. 4 shows a block diagram of the closed loop limit control set point calculation. FIG. 5 shows a block diagram of the open loop limit control manipulated variable set point calculation when the limit set point is an upper limit. FIG. 6 shows a block diagram of the open loop limit control manipulated variable set point calculation when the limit set point is an lower limit. FIG. 7 shows a relationship between the open loop and closed loop limit set points and an undesirable region in which limit control is exercised. FIG. 8 shows an electric driven turbocompressor with variable inlet guide vanes, instrumentation, and a control system. FIG. 9 shows a gas-turbine driven turbocompressor with instrumentation and a control system. FIG. 10a shows a suction pressure transmitter providing a suction pressure signal for use as a limit variable. FIG. 10b shows an interstage pressure transmitter providing a interstage pressure signal for use as a limit variable. FIG. 10c shows a discharge pressure transmitter providing a discharge pressure signal for use as a limit variable. FIG. 10d shows a discharge steam temperature transmitter providing a discharge steam temperature signal for use as a limit variable. FIG. 10e shows a, exhaust gas temperature transmitter providing a exhaust gas temperature signal for use as a limit variable. DETAILED DESCRIPTION OF THE INVENTION A typical two-stage compression system is shown in FIG. 1. The two turbocompressors 100, 105, on a single shaft, are driven by a single gas or steam turbine 110. A suction pressure transmitter, PT1 115, is provided in the suction of the first compression stage 100. An interstage pressure transmitter, PTI 120, is used to measure a pressure between the compression stages 100, 105, preferably located to measure the highest pressure found in the interstage, or the pressure in an interstage vessel 125 having a maximum pressure constraint. The discharge pressure is measured by a discharge pressure transmitter, PT3 130. Any of these pressures may require limit control to keep them within predetermined bounds. Antisurge valves 135, 140 may be used as manipulated variables, M, for limit control of several limited variables. The low pressure stage's 100 antisurge valve 135 can be used to keep the turbocompressor's 100 operating point in a stable operating region, that is, out of the surge region. The same antisurge valve 135 may be used to keep the suction pressure of the first compression stage 100 from dropping below a minimum suction pressure limit. It may also be used to keep the interstage pressure from exceeding a maximum interstage pressure limit. Similarly, the high pressure stage's 105 antisurge valve 140 may be used to keep the second compression stage's 105 operating point from entering into its surge region. The same high-pressure antisurge valve may be used to keep the discharge pressure from exceeding a maximum limit. An intercooler 145 serves to reduce the temperature of the compressed gas leaving the first compression stage 100 before it reaches the second compression stage 105. The interstage vessel 125 may serve as a knockout drum, permitting liquids to be separated from gases and removed from the stream. An aftercooler 150 is found in many compression systems. Again, a knockout drum 155 may be necessary downstream of the aftercooler 150 to remove liquids condensed from the gas. A single turbocompressor 200 is shown being driven by a steam turbine 210 in FIG. 2. Instrumentation for antisurge and speed control is shown. At the suction of the turbocompressor 200, a flow transmitter, FT 220, and a suction pressure transmitter, PT1 215, are shown. At the turbocompressor's 200 discharge, a pressure transmitter, PT2 220, is shown. Each of those transmitters sends a signal to an antisurge controller 230 that manipulates an antisurge valve 240 to keep the turbocompressor's 200 operating point from entering surge. Secondary control may be implemented in the antisurge controller 230 to limit the suction pressure and/or the discharge pressure to acceptable levels using the antisurge valve 240 as a manipulated variable, M. A speed pickup and transmitter, ST 250, is used by the speed controller 260 to regulate the steam turbine's 210 rotational speed. To accomplish this, the speed controller 260 manipulates the steam turbine's 210 steam valve or rack 270. The speed controller will serve to keep the turbine's 210 rotational speed between upper and lower bounds, therefore, speed control is inherently constraint control. Closed and open loop limit control strategies must be coordinated to avoid oscillations. The flow diagram of FIG. 3 shows the interaction. The limit variable, L 300, such as a turbocompressor 200 suction pressure, is compared to an open loop threshold in a first comparator block 310, which may be an upper bound or a lower bound. Using the example of a suction pressure as L 300, the threshold would be a lower bound. That is, the turbocompressor's 200 suction pressure should remain greater than or equal to the threshold value, which is, typically, slightly above atmospheric pressure. The first temporal derivative of L 300, dL/dt is calculated in a derivative block 305. If the value of the limit variable, L 300, has crossed the threshold, a check is made on the value of dL/dt in a second comparator block 320. The value and sign of dL/dt helps to determine if the system is on the way to recovery, even if the value of L has not been restored to an acceptable value. For instance, let the turbocompressor's 200 suction pressure drop below its minimum limit, noting that dL/dt=dps/dt (where p is the turbocompressor's 200 suction pressure). If dL/dt is found to be positive, that is, the suction pressure is increasing, it is concluded that the suction pressure is responding to the control action. Measuring the magnitude of dL/dt, as well, yields a measure of the rate of recovery. So, after open loop control action has been initiated, even if L has not been restored to a safe level, if dL/dt has a sign and, optionally, a magnitude indicating recovery, and the magnitude indicates an acceptable rate of recovery, limit control of L may be passed back to closed loop control 330 as indicated in FIG. 3. If the magnitude and/or sign of dL/dt do not meet the threshold requirements of the second comparator block 320, open loop control 340 is again initiated. The closed loop control scheme is shown in more detail in FIG. 4. A value of L 300 is obtained from a transmitter or calculation and passed to the closed loop Proportional-Integral-Derivative (PID) limit controller 400 as its limit control process variable. The remainder of FIG. 4 represents the calculations used to determine an appropriate set point for the closed loop PID limit controller 400. The critical limit variable, L 300, is also an input to the derivative block 305, where the first temporal derivative, dL/dt is calculated. A function of the derivative, dL/dt, is calculated in a function block 405. An example of such a function is simply proportionality. The present invention is not limited to a particular function. The output of the function block 405 is shown in FIG. 4 as being an adjustment for the safety margin, SM adj n + 1 , or an accumulated safety margin. Another possibility is for the output of the function block 405 to be a set point; however, for explanation purposes, a safety margin has the advantage of being strictly positive (so, if we add to the safety margin, the control is more conservative). When additional safety margin has been added to a minimum safety margin, as the danger passes, the additional safety margin is reduced at a predetermined rate or rates. Therefore, a check is made in a logic block 410 to assure the newly calculated accumulated safety margin, SM adj n + 1 , is not smaller than the accumulated safety margin, SMadjn, calculated at the previous scan. If the new accumulated safety margin, SM adj n + 1 , is found to be smaller than the previous accumulated safety margin, SMadjn, the new accumulated safety margin, SM adj n + 1 , is set to the old value, SMadjn in the logic block 410. To effect the reduction of an accumulated safety margin, SM adj n + 1 , a constant or variable value, ΔSM 415, is subtracted from the accumulated safety margin in a first summation block 420. A constant value of ΔSM 415 will result in a ramping of the accumulated safety margin, SM adj n + 1 . Another viable possibility is an exponential decay. The present invention is not limited to a particular method of reducing an accumulated safety margin, SM adj n + 1 . The instantaneous value of the accumulated safety margin, SM adj n + 1 , is stored in a memory block 425 as the old value of the accumulated safety margin, SMadjn, to be used in the next scan of this process. The accumulated safety margin, SM adj n + 1 , is added to a minimum safety margin, SM 430, in a second summation block 435. The result is the closed loop safety margin, SMCL+1 440. The value of SMCLn+1 440, and its first temporal derivative, dSMCLn+1/dt 445 are passed into a rate check block 450 where the speed at which the safety margin can change is limited. A provisional safety margin, SM prov n + 1 , results from the rate check block 450. This provisional safety margin, SM prov n + 1 , is checked for magnitude in the bounds check block 455. In the bounds check block 455, the magnitude of the safety margin may be bounded both above and below. The result of the bounds check block 455 is the final value of the safety margin, SMn+1, which is summed with the closed loop set point Lsp 465 in a third summation block 460 to produce a closed loop set point SPCL utilized by the closed loop PID 400. Flow diagrams illustrating the operation of the open loop limit controller are shown in FIGS. 5 and 6. In FIG. 5, it is assumed that the limit on L 300 is an upper limit while in FIG. 6, the limit on L 300 would be a lower limit. The value of L 300 and its set point, LSP 465, must be made available to the open loop control system 500. Again, a first derivative with respect to time, dL/dt is taken of the limit variable, L 300, in a derivative block 305. The value of dL/dt from the derivative block 305 is used in a first function block 510 to calculate a value for an instantaneous open loop safety margin, SMOLn+1 515. A first summation block 520 sums the instantaneous closed loop safety margin, SMCLn+1 440, the instantaneous open loop safety margin, SMCLn+1 515, and the base set point for L 300, LSP 465. The result is a value of the open loop set point, SPOL. In a first comparator block 525, 625, the value of L 300 is compared with the set point SPOL to determine if open loop action is required. If this test indicates open loop action is not needed, the process begins anew. If it appears as if open loop action is required, another test is carried out in a second comparator block 530, 630. Here, it is determined if the sign of the first derivative of L 300 from the derivative block 305 is negative (positive in FIG. 6), indicated a recovery from the limit condition, and that the magnitude of the rate of change is greater than a set point, SPdL/dt. This test indicates whether the system is recovering satisfactorily, and that open loop (or additional open loop) action is not required. Again, if recovery seems imminent, the process begins anew and control is passed to the closed loop limit control system. If the result of this test in the second comparator block 530 is “No,” the flow continues to a second summation block 535 where the present value of the manipulated variable (for instance, a valve position), M 540 is summed with an open loop increment, ΔM (calculated in a second function block 545 as a function of dL/dt), to yield a new set point, SPM 550, for the manipulated variable. FIG. 7 illustrates the relative locations of the open loop and closed loop limit set points and the undesirable region in which limit control should be in force. The example used is that of turbocompressor suction pressure, which has a low limit. That is, the turbocompressor's suction pressure should remain greater than a chosen limit. Another configuration of compressor/driver is shown in FIG. 8, wherein the compressor 200 is driven by an electric motor 810. Such electric motors 810 may be variable speed, but most commonly are constant speed. Capacity or performance control is carried out using guide vanes such as variable inlet guide vanes 820 shown. The variable guide vanes are manipulated via an actuator 830 by the guide vane controller 860 to maintain a suction pressure, discharge pressure or flow rate (typically) at a set point. A possible limit variable, maintained in a safe operating region by limit control, is the electric motor power, J, as measured by the power transmitter 840. Motor power may require limiting from above. Still another compressor/driver combination is shown in FIG. 9 wherein the driver is a single or multiple shaft gas turbine 910. A speed controller 260 is, again, used. A limit control loop may be incorporated within the speed controller 260 for the purpose of limiting an exhaust gas temperature as measured and reported by the exhaust gas temperature sensor 915. Reducing a flow of fuel by reducing the opening of the fuel valve 970 causes the exhaust gas temperature to lower. In FIGS. 10a-10e various values, reported by sensors, are shown being used as limit variables, L. The instant invention is not limited to the values shown in these figures. In FIG. 10a, a turbocompressor's suction pressure, ps, is transmitted by a suction pressure transmitter, PT1 215, to be used as a limit variable, L 300, as shown in FIGS. 3-6. In FIG. 10b, the limit variable is turbocompressor interstage pressure, p2. In FIG. 10c, the limit variable is turbocompressor discharge pressure, pd. In FIG. 10d, the limit variable is steam turbine discharge pressure, T2. Finally, in FIG. 10e, the limit variable is the Exhaust Gas Temperature (E.G.T.) of a gas turbine. The above embodiment is the preferred embodiment, but this invention is not limited thereto. It is, therefore, apparent that many modifications and variations of the present invention are possible 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. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates generally to a control scheme. More particularly the present invention relates to a method and apparatus for more accurately and stably limiting critical variables associated with a process such as those including turbomachines such as a turbocompressor, steam turbine, gas turbine, or expander. 2. Background Art The safe operating regime of a turbocompressor is constrained by the machinery and process limitations. A turbine-driven turbocompressor is generally bound by upper and lower limits of a turbine operating speed, a surge line, a choke limit, high discharge or low suction pressure bounds, and/or a power rating of the turbine. Limit control is used to keep the turbocompressor from entering an operating regime that is not considered safe, is unacceptable from a process standpoint, or undesirable for any reason. Limit control, also referred to as constraint control, is defined as a control strategy that will take action to avoid operating in these undesirable operating regimes, but only takes action when there is a tendency or danger of operating therein. Take, for example, a turbocompressor's discharge pressure that is to be constrained to remain at or below a set point, p sp . When the turbocompressor's discharge pressure is below p sp , no particular action is taken by the limit control system to adjust p sp . Only when the turbocompressor's discharge pressure reaches or exceeds p sp is control action taken. Limit control strategies differ from ordinary control strategies in that: ordinary control strategies take measures to keep the process variable at its set point at all times (generally speaking), keeping the process variable from dropping below its set point as well as keeping it from exceeding its set point; limit control strategies are brought to bear only when a limit variable crosses its set point. On one side of its set point, the limit control scheme is not in effect. Often, a rigid limit set point exists where a safety system, associated with the machinery or process, causes the machinery to shut down, or a relief valve to open, etc. The process control system, on the other hand, makes use of soft set points. A soft set point is separated from its associated rigid set point by a safety margin. Minimization of the safety margins results in an expanded operating envelope. Advanced antisurge control systems have been applied very successfully in many applications to prevent the turbocompressor from damages due to surge. In U.S. Pat. No. 4,949,276, a method of antisurge control is disclosed using a speed of approach to surge to increase the safety margin. Once the compressor's operating point has reached the controller's surge control line, closed loop control attempts to prohibit surge by opening an antisurge valve. Open loop control is disclosed in U.S. Pat. Nos. 4,142,838 and 4,486,142. Here, an open loop control line is located toward surge from the surge control line. If closed loop control is unable to keep the compressor's operating point from reaching this open loop control line, an open loop control action will cause the antisurge valve to open as quickly as possible a predetermined increment. A scheme similar to that just described for antisurge control was patented in U.S. Pat. No. 5,609,465 for overspeed control in turbines. Here, a steam valve is closed a predetermined increment as quickly as possible by an open loop control action. Such advanced control schemes have not been applied for other constraints imposed on turbomachinery. Surge and overspeed are known to cause process upsets, but are somewhat unique in their ability to cause damage and destruction to the turbomachinery and adjacent equipment, and even to be dangerous to personnel. In the past, there was no motivation to apply these advanced techniques, along with their complexity, to other constrain control problems. In fact, common understanding taught that an open loop action would cause process upsets, thereby teaching away from the use of these advanced control schemes that resulted in what were considered severe reactions to process events causing a control action. Recently however, competitive conditions and political-economic-environmental issues such as the restriction on carbon dioxide emissions have resulted in reconsidering control strategies to squeeze the last percentage of efficiency from processes, and expand the operating envelope of the process as much as possible. For instance, because of a process upset or a change in operating conditions, a turbocompressor's suction pressure may drop below atmospheric pressure, a condition that can cause air to be entrained in a hydrocarbon being compressed. Or the turbocompressor's interstage pressure may exceed a maximum pressure rating for the machinery casing or process vessels. Present-day control systems typically utilize a secondary-variable closed-loop control scheme to constrain the turbomachine's operating point within predetermined bounds. When a limit-control variable reaches its set point, control is bumplessly transferred from primary variable control to secondary variable limit control and the manipulated variable of the turbomachine is adjusted to bring and/or keep the offending limit-control variable within acceptable limits. Due to excessive dead times or large time constants in the overall system, traditional PID based constraint control actions may sometimes be inadequate to prevent an excursion of a critical process variable into a restricted region caused by a process upset. Moreover the set points configured for limit control are fixed. Therefore, limit control is initiated only if a variable crosses its predetermined limit, that is, a measurable error is incurred. Increasing the gains of the controller may not mitigate the problem due to the overall system's sluggishness (long dead times or large time constants). The best solution to this situation is to configure the control system with conservative safety margins. This invariably contracts the available operating zone of the turbocompressor. The consequence of such a control approach is a decrease in the turbocompressor's throughput with its associated significant impact on plant production. There is, therefore, a need for a limit-control strategy that effectively and stably results in the constraining of limited variables, while bumplessly transferring between primary variable control and constraint variable control. | <SOH> BRIEF SUMMARY OF THE INVENTION <EOH>A purpose of this invention is to provide a method and apparatus for limiting or constraining critical variables, herein referred to, generically, as “L,” associated with a turbocompressor. Another purpose is to initiate limit-control action such that a limited variable does not cross its base set point. Still another purpose of the present invention is to carry out limit control and the transfer between primary variable control and limit control smoothly and stably. Using a combination of closed loop and open loop responses, the limit-control action is designed to minimize the excursion of critical variables, L, related to a turbocompressor, turbine, expander or its associated process, beyond their set points. Some examples of critical limit (constraint) variables, L, are turbocompressor suction, interstage, and discharge pressures, gas turbine exhaust gas temperature, gas and steam turbine power, machinery rotational speed, and various process pressures and temperatures. Antisurge control is, inherently, limit control, with the limit variable being a measure of a proximity to surge. Fixing the set point for constraint control action can increase the overall response time of the control system. To circumvent this problem, the set point of the constraint-control loop is dynamically adjusted as a function of measurable process disturbances. Care must be taken to ensure that dynamic adjustment to the set point does not result in premature control actions on the manipulated variable (herein generically referred to as “M”) that negatively influence the process. In a preferred embodiment, dynamic correction to the set point of each critical limit variable, L, is made as a function of the first derivative with respect to time, dL/dt, of that critical limit variable. In addition, these set point adjustments are rate limited and bound within acceptable levels in each direction (that is, increasing or decreasing) with the ability to configure independent rates and bounds as required. An additional aspect of the present invention involves a fast acting, open loop, control response in the event the closed loop constraint control proves inadequate. An acceptable threshold of overshoot of a critical process variable measured from its defined constraint control set point is used as an indication of the effectiveness of closed loop action. Once the constrained variable has reached this overshoot threshold, a rapid change in the manipulated variable, M, is initiated to bring the constrained variable back to an acceptable value. This rapid alteration of the manipulated variable, M, is known as an “open loop” response. Specific methods of open-loop control action include a configurable step response, or fast ramp output to the manipulated variable. The open-loop output is adjusted for system dead time or hysteresis. The open loop control response may be repeated with appropriate pause between repetitions as needed to bring the operating point out of an undesirable state. An additional indication of the effectiveness of closed loop action is to identify if a magnitude of a first temporal derivative of a critical process variable exceeds a configurable threshold. Once the open-loop control response is found to be effective, the constraint-control action transitions over to closed loop control in a bumpless manner. A criterion such as a value of the critical process variable compared to its limit set point may be used to determine the point of switchover from open loop action to closed loop control. It is important to ensure that the switchover from open loop action to closed loop control not result in oscillations of the overall system as observed with traditional control systems. Such traditional systems typically employ high gains for constraint control action. In the preferred embodiment of this invention, this is realized by modifying the response of the open loop or closed loop in the return direction. It is important to limit the suction pressure of turbocompressors handling explosive gases. Suction pressure limit-control applications of the present invention include: cracked gas turbocompressors in Ethylene plants, propylene or ethylene refrigeration turbocompressors in gas processing and Olefins plants, propane refrigeration compressors in LNG processes, wet gas compressors in Refineries, and Ammonia refrigeration compressors in fertilizer plants. Interstage pressures may require limiting due to limitations on the machinery casing, or intercoolers or vessels located between stages. Applications for interstage pressure limit control are: fluidized catalytic cracking applications, cracked gas turbocompressors in Ethylene plants, pipe line gas turbocompressors, refrigeration turbocompressors in gas processing, and the turbocompressors used in LNG plants and Ammonia plants. Turbocompressor discharge pressure may require limiting as well due to machinery casing or discharge process component limitations. As mentioned above, there are two types of limit set points spoken of in process control. A rigid limit set point exists where a safety system, associated with the machinery or process, causes the machinery to shut down, or a relief valve to open, etc. The process control system, on the other hand, makes use of soft set points. A soft set point is separated from its associated rigid set point by a safety margin. In this application, only soft set points are of interest. The novel features which are believed to be characteristic of this invention, both as to its organization and method of operation together with further objectives and advantages thereto, will be better understood from the following description considered in connection with the accompanying drawings in which a presently preferred embodiment of the invention is illustrated by way of example. It is to be expressly understood however, that the drawings are for the purpose of illustration and description only and not intended as a definition of the limits of the invention. | 20040113 | 20060829 | 20050714 | 68473.0 | 0 | CASAREGOLA, LOUIS J | METHOD AND APPARATUS FOR THE PREVENTION OF CRITICAL PROCESS VARIABLE EXCURSIONS IN ONE OR MORE TURBOMACHINES | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,756,560 | ACCEPTED | Implementation of gradual impedance gradient transmission line for optimized matching in fiber optic transmitter laser drivers | A transmitter in a fiber optic system is provided, including a driver circuit, a light emitting source, and transmission lines. The driver circuit is configured to receive a modulated electrical signal and to have a driver circuit output impedance. The light emitting source has a light emitter impedance that is different than the driver circuit output impedance. The light emitting source is configured to receive the modulated electrical signal such that it produces a modulated optical signal proportional to modulated electrical signal. The transmission lines are coupled between the driver circuit and the light emitting source for transmitting the modulated electrical signal from the driver circuit to the light emitting source. The transmission lines gradually change the impedance between the driver circuit and the light emitting source so as to gradually match the driver circuit output impedance to the light emitter impedance. | 1. A transmitter in a fiber optic system, the transmitter comprising: a driver circuit configured to receive a modulated electrical signal and to have a driver circuit output impedance; a light emitting source having a light emitter impedance different than the driver circuit output impedance, the light emitting source configured to receive the modulated electrical signal such that it produces a modulated optical signal proportional to modulated electrical signal; and tapered transmission lines having a length between a first end and a second end, the tapered transmission lines coupled to the driver circuit at the first end and to the light emitting source at the second end such that the transmission lines transmit the modulated electrical signal from the driver circuit to the light emitting source, the transmission lines configured such that impedance of the transmission lines gradually changes over the length so that the tapered transmission lines match the impedance of the driver circuit at the first end and match the impedance of the light emitter at the second end. 2. The transmitter of claim 1 wherein the tapered transmission lines gradually change the capacitance and impedance along the length such that the tapered transmission lines gradually match the driver circuit output impedance at the first end to the light emitter impedance at the second end without use of lumped circuit components. 3. The transmitter of claim 1 wherein the tapered transmission lines comprise two lines spaced apart in a transmission plane, the transmission plane being located adjacent a ground plane. 4. The transmitter of claim 3 wherein the two lines are spaced apart from each other at the first end by a first distance and spaced apart from each other at the second end by a second distance, the first distance being greater than the second distance. 5. The transmitter of claim 3 wherein the two lines are spaced apart from each other at the first end by a first distance and spaced apart from each other at the second end by a second distance, the first distance being less than the second distance. 6. The transmitter of claim 3 wherein the lines in the transmission plane are spaced apart from the ground plane at the first end by a first distance and wherein the lines in the transmission plane are spaced apart from the ground plane at the second end by a second distance, the first distance being greater than the second distance. 7. The transmitter of claim 3 wherein the lines in the transmission plane are spaced apart from the ground plane at the first end by a first distance and wherein the lines in the transmission plane are spaced apart from the ground plane at the second end by a second distance, the first distance being less than the second distance. 8. The transmitter of claim 3 wherein each of the lines has a varying diameter over the length of the transmission lines such that the diameters of the two lines at the first end are smaller than the diameters of the two lines at the second end. 9. The transmitter of claim 3 wherein each of the lines has a varying diameter over the length of the transmission lines such that the diameters of the two lines at the first end are larger than the diameters of the two lines at the second end. 10. The transmitter of claim 1 wherein the driver circuit output impedance is higher than the light emitter impedance. 11. The transmitter of claim 1 wherein the driver circuit output impedance is between 50 Ohms and 75 Ohms and the light emitter impedance is between 5 Ohms and 25 Ohms such that that transmission line impedance gradually changes over its length from between 50 Ohms and 75 Ohms to between 5 Ohms and 25 Ohms. 12. The transmitter of claim 1 wherein the driver circuit is a laser driver circuit and the light emitter source is a laser diode. 13. The transmitter of claim 1 wherein the driver circuit is a light emitting diode driver circuit and the light emitter source is a light emitting diode. 14. The transmitter of claim 1 wherein the driver circuit output impedance is 50 Ohms and the light emitter impedance is 5 Ohms and the transmission lines taper to gradually decrease impedance so as to match the driver circuit and the light emitter source. 15. A fiber optic communication system comprising: a signal transmitter that produces an optical signal of varying light intensity, the transmitter further comprising: a driver circuit configured to receive an original modulated electrical signal and to generate a driver electrical signal, the driver circuit configured to have a driver circuit output impedance; a light emitting source having a light emitter impedance different than the driver circuit output impedance, the light emitting source configured to receive the original modulated electrical signal such that it produces the optical signal of varying light intensity that is proportional to the original modulated electrical signal; and tapered transmission lines coupled between the driver circuit and the light emitting source such that the transmission lines transmit the driver electrical signal from the driver circuit to the light emitting source, the tapered transmission lines tapered such that impedance of the transmission lines gradually changes such that the tapered transmission lines match both the driver circuit output impedance and the light emitter impedance; an optical fiber coupled to the signal transmitter that receives and transmits the optical signal; and a receiver coupled to the optical fiber that receives the optical signal and converts the received optical signal into an output electrical signal that is a replica of the original modulated electrical signal. 16. The fiber optic communication system of claim 15 wherein the tapered transmission lines gradually change the impedance along such that the tapered transmission lines gradually match the driver circuit output impedance to the light emitter impedance without use of lumped circuit components. 17. The fiber optic communication system of claim 15 wherein the tapered transmission lines comprise two lines spaced apart from each other immediately adjacent the driver circuit by a first distance and spaced apart from each other immediately adjacent the light emitter by a second distance, the first distance being greater than the second distance. 18. The fiber optic communication system of claim 15 wherein the tapered transmission lines comprise two lines spaced apart in a transmission plane, the transmission plane being located adjacent a ground plane and wherein the lines in the transmission plane are spaced apart from the ground plane immediately adjacent the driver circuit by a first distance and wherein the lines in the transmission plane are spaced apart from the ground plane immediately adjacent the driver circuit by a second distance, the first distance being greater than the second distance. 19. The fiber optic communication system of claim 15 wherein the tapered transmission lines comprise two lines having varying diameter over such that the diameters of the two lines immediately adjacent the driver circuit are smaller than the diameters of the two lines immediately adjacent the driver circuit. 20. A transmitter in a fiber optic system, the transmitter comprising: a driver circuit configured to receive a modulated electrical signal and to have a driver circuit output impedance; a light emitting source having a light emitter impedance different than the driver circuit output impedance, the light emitting source configured to receive the modulated electrical signal such it produces a modulated optical signal proportional to modulated electrical signal; and matching means coupled between the driver circuit and the light emitting source for transmitting the modulated electrical signal from the driver circuit to the light emitting source and for gradually changing the impedance between the driver circuit and the light emitting source so as to gradually match the driver circuit output impedance to the light emitter impedance. | BACKGROUND This invention relates to a transmitter in a fiber optic system. The transmitter utilizes a transmission line that is configured to achieve optimized impedance matching without use of an impedance matching network. Fiber optic systems generally have three main components, a transmitter, a transmission medium, and a receiver. Fiber optic systems use light pulses to transmit information down fiber lines, which are then received and generally translated to electrical signals. Optical receivers generally receive and convert a modulated light signal coming from the optical fiber back into a replica of the original signal, which was applied to the transmitter. A transmitter generally includes driver circuit and an optical emitter that are electrically coupled. The optical emitter can be a laser or LED. The driver circuit receives a modulated electrical signal that contains information that is to be transmitted over the optical fiber in the form of a modulated optical signal. The driver circuit is coupled to the laser or LED and is configured to cause the light-emitting device to generate a modulated optical signal based upon the modulated electrical signal. Modern day fiber optic systems are required to be operated at increasingly high frequency rates. The frequency of the electrical signal sent from the driver circuit to the light emitter is often so high that the signal acts like a wave. Accordingly, one important consideration for driver circuits in driving light emitters in the transmitters of the fiber optic system is impedance matching of the elements. If the output of the driver circuit has different impedance than does the light emitter, signal reflections will occur. Signal reflections disturb the standing-wave oscillation and cause intersymbol interference in the light emitter that can cause significant intolerable error in the fiber optic transmission system. In order to compensate for mismatched impedance, most transmitters also include an impedance matching network that can interface the output of the driver circuit with the light emitter such that the impedance will appear matched from both the light emitter and from the driver circuit. Typically a light emitter load like a laser will have lower impedance than the output of the driver circuit. Consequently, a typical matching network will include a plurality of resistive elements that will deflect some of the signal from the light emitter so that the impedance matching and there will be no reflections. Unfortunately, these matching networks cause significant wasted energy in the system and are often difficult to place where required due to geometric restrictions. Because part of the signal goes through these matching networks so that impedance will be well matched, portions of the signal are typically going though resistors in the matching network that are parallel with the load. Some of this diverted current will release energy as heat, which is wasted energy in the system. Energy from the diverted current in the matching network that is not released as heat can instead generate electromagnetic interference, which can cause additional problems for other parts of the system. SUMMARY The present invention is a transmitter for use in a fiber optic system. The transmitter includes a driver circuit, a light emitting source, and transmission lines. The driver circuit is configured to receive a modulated electrical signal and to have a driver circuit output impedance. The light emitting source has a light emitter impedance that is different than the driver circuit output impedance. The light emitting source is configured to receive the modulated electrical signal such it produces a modulated optical signal proportional to modulated electrical signal. The transmission lines are coupled between the driver circuit and the light emitting source for transmitting the modulated electrical signal from the driver circuit to the light emitting source. The transmission lines gradually change the impedance between the driver circuit and the light emitting source so as to gradually match the driver circuit output impedance to the light emitter impedance. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification. The drawings illustrate the embodiments of the present invention and together with the description serve to explain the principles of the invention. Other embodiments of the present invention and many of the intended advantages of the present invention will be readily appreciated as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding similar parts. FIG. 1 illustrates a fiber optic system. FIG. 2 illustrates a transmitter in a fiber optic system. FIGS. 3A-3D illustrate tapered transmission lines in a transmitter in accordance with the present invention. DETAILED DESCRIPTION In the following Detailed Description, reference is 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. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” “leading,” “trailing,” etc., is used with reference to the orientation of the Figure(s) being described. Because components of embodiments of the present invention can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims. FIG. 1 illustrates fiber optic system 10. A fiber optic system 10 includes transmitter 12, receiver 14, electrical input connector 16, optical connectors 18 and 22, optical fiber 20, and output signal connector 24. In operation, transmitter 12 is coupled to an information source by input connector 16. The information source transfers information via a modulated electrical signal, which is coupled to electrical connector 16 and then to transmitter 12. Transmitter 12 contains a light source, typically a LED or a laser. The light source is driven by the electrical signal received by transmitter 12. This generates a modulated optical signal which is then transmitted to optical fiber 20. Optical fiber 20 generally includes a cylindrical core, a concentric cylindrical cladding surrounding the core, and a concentric cylindrical protective jacket or buffer surrounding the cladding. The core is made of transparent glass or plastic having a certain index of refraction. The cladding is also made of transparent glass or plastic, but having a different, smaller, index of a fraction. Optical fiber 20 acts as a bendable waveguide and its characteristics are largely determined by the relative refractive indices of the core and the cladding. The optical fiber 20 can be routed over distances such that transmitter 12 and receiver 14 may be located in distant locations relative to each other. Optical fiber 20 is coupled to receiver 14 via optical connector 22. Receiver 14 includes an optical detector and related electronic circuitry. Typically, the optical detector is a photodiode of either a PIN or avalanche type. The optical detector typically has a relatively large sensitive detecting area that can be several hundred microns in diameter. Consequently, optical signals from optical fiber 20 can be easily detected by the optical detector. When optical signals reach the optical detector, it converts the optical energy, in the form of photons, into electrical energy. The output of the optical detector is a flow of electrical current that is proportional to the received optical power signals. This electrical current is then received by the receiver electronic circuitry for further processing. The output signal is a replica of the original signal, which was applied to the transmitter 12. FIG. 2 illustrates an exemplary implementation transmitter 12 in accordance with the present invention. Transmitter 12 includes laser driver circuit 30, transmission line 32, and laser 34. An original modulated electrical signal that contains information to be transmitted over the fiber optic system 10 is received by transmitter 30 via coupler 16 and sent to laser driver circuit 30 for processing. Laser driver circuit 30 is coupled to laser 34 by transmission line 32 and generates an electrical driver signal from the modulated electrical signal. The electrical driver signal is transmitted over transmission line 32 to laser 34 thereby causing laser 34 to produce an optical output directly proportional to the electrical driver signal and the original modulated electrical signal. This optical output is transmitted to the optical fiber 20 via coupler 18. One skilled in the art will recognize that laser 34 could also be a different light-emitting source, such as a light emitting diode, consistent with the present invention. Laser driver circuit 30 is configured to receive the original modulated electrical signal at a very high frequency. Such frequencies can be on the order of several gigahertz or more. Similarly, the driver electrical signal sent from the driver circuit 30 to the laser 34 is of such high frequency that the signal acts like a wave. Accordingly, it is important that the output impedance of driver circuit 30 be matched to the input impedance of laser 34 in order to avoid signal reflections and noise in laser 34. When the transmission line 32 is much longer than the wavelength of the signal, signal reflections will disturb the standing-wave oscillation and cause noise in the light emitter that can cause significant intolerable error in the fiber optic transmission system 10. The transmission line 32 in fiber optic system 10 may be on the order of 1 inch or more, such that signals on the order of gigahertz will cause very significant reflections in unmatched systems. Typically, however, the output impedance of driver circuit 30 is not matched to the input impedance of laser 34. In fact, in some embodiments of the present invention, the output impedance of driver circuit 30 is between 50 Ohms and 75 Ohms, and the input impedance of laser 34 is between 5 Ohms and 25 Ohms. In some cases, the output impedance of driver circuit 30 is greater than or equal to 100 Ohms. Consequently, in order to avoid signal reflections between driver circuit 30 and laser 34 the impedance must be matched. Rather than using an impedance matching network with lumped circuit components, however, transmission line 32 is used to gradually match impedance, and thereby avoid signal reflections between driver circuit 30 and laser 34. Using transmission line 32 to both transmit the driver electrical signal and to gradually match the impedance between driver circuit 30 and laser 34 avoids the significant wasted energy that occurs with impedance matching network. It also avoids energy being release from the system as heat or as electromagnetic interference. Furthermore, the impedance of transmission line 32 changes slowly over time. Because impedance transitions slowly, the reflections are not large steps and reflections are minimized. Since the system is essentially matched as the signal moves from driver circuit 30 to laser 34, it eliminates the issue of reflection and it also allows most of the actual power to go though to the laser 34. FIGS. 3A-3D illustrate a variety of ways in which transmission line 32 can be tapered in order to achieve the gradual change in impedance of the line in accordance with the present invention. For example, in FIG. 3A, transmission line 32 is illustrated by first and second lines 40 and 42. Lines 40 and 42 connect between driver circuit 30 and laser 34. Where lines 40 and 42 connect to driver circuit 30 they are separated from each other by a distance X40-42. Where lines 40 and 42 connect to laser 34 they are separated from each other by a distance Y40-42. Distance X40-42 is larger than distance Y40-42 such that lines 40 and 42 are farther from each other immediately adjacent driver circuit 30 then they are immediately adjacent laser 34. In this way, the impedance of transmission line 32 changes slowly so that it starts off matching the higher output impedance of driver circuit 30 and ends up matching the lower impedance of the input of laser 34. This slow gradual change provides excellent matching characteristics, and avoids losses associated with prior systems. In one embodiment, lines 40 and 42 are rectangular in cross-section and are made of a metallic material. As metal lines 40 and 42 get closed together, moving from X40-42 to Y40-42, the capacitance between the two increase and the impedance decreases. This provides the gradual impedance matching characteristics of lines 40 and 42. In one embodiment, the distance between lines 40 and 42 changes from X40-42 to Y40-42 linearly, such that there is a constant change in the distance between lines 40 and 42 over their length from driver circuit 30 to laser 34. In another embodiment, the change is exponential, such that there is an increasing change in the distance between lines 40 and 42 over their length from driver circuit 30 to laser 34. Various different configurations for varying distances between lines 40 and 42 are possible to achieve a gradual change in impedance over the length of transmission lines 32 such that output impedance of driver circuit 30 is matched at one side and input impedance of laser 34 is matched at the other side. In FIG. 3B, transmission line 32 is illustrated by first and second lines 44 and 45. Lines 44 and 45 are connected between driver circuit 30 and laser 34 and are parallel to each other in a single transmission plane. They are illustrated in FIG. 3B as a single line. Lines 44 and 45 and the transmission plane are separate from a ground plan 46. Where lines 44 and 45 connect to driver circuit 30 they are separated from ground plane 46 by a distance X44-46. Where lines 44 and 45 connect to laser 34 they are separated from ground plane 46 by a distance Y44-46. Distance X44-46 is larger than distance Y44-46 such that lines 44 and 45 are farther from the ground plane 46 immediately adjacent driver circuit 30 then they are immediately adjacent laser 34. In this way, the impedance of transmission line 32 changes slowly so that it starts off matching the higher output impedance of driver circuit 30 and ends up matching the lower impedance of the input of laser 34. This slow and gradual change provides excellent matching characteristics, and avoids losses associated with prior systems. In FIG. 3C, transmission line 32 is illustrated by first and second lines 48 and 50. Lines 48 and 50 are connected between driver circuit 30 and laser 34. Where lines 48 and 50 connect to driver circuit 30 they each have smaller diameters X48 and X50. Where lines 48 and 50 connect to laser 34 they each have larger diameters Y48 and Y50. Diameter X48 immediately adjacent driver circuit 30 is smaller than diameter Y48 immediately adjacent laser 34 such that the diameter of line 48 gradually tapers down from driver circuit 30 to laser 34. Similarly, diameter X50 immediately adjacent driver circuit 30 is smaller than diameter Y50 immediately adjacent laser 34 such that the diameter of line 50 gradually tapers down from driver circuit 30 to laser 34. In this way, the impedance of transmission line 32 changes slowly so that it starts off matching the higher output impedance of driver circuit 30 and ends up matching the lower impedance of the input of laser 34. This slow gradual change provides excellent matching characteristics, and avoids losses associated with prior systems. FIG. 3D illustrates the characteristics of transmission lines 32. Essentially, the tapering of transmission line 32 is the circuit equivalent of a R-C network providing a gradual change in impedance along the length of transmission line 32. In FIG. 3D this is shown as inductors L1 through L3 and capacitors C1 through C4 connected in a network to provide a gradual impedance change over a distance between driver circuit 30 and laser 34. For example, in a fiber optic system 10 where the output impedance of driver circuit 30 is 50 Ohms and the input impedance of laser 34 is 5 Ohms, the impedance of the transmission line 32 changes slowly so that it starts off at 50 Ohms and over the length of transmission line 32 it becomes 5 Ohms. This gradual transition, due to the tapered transmission line 32, eliminates the issue of reflection and it also allows most of the actual power to go though to the laser 32. The actual tapering of transmission line 32 to effectuate the gradual impedance matching can be implemented in transmitter 12 in a variety of ways, as illustrated by FIGS. 3A-C and the accompanying explanations. These various tapering techniques could also be combined in various ways to achiever gradual impedance matching. Other configurations are also available, independently or in combination with these configurations, to achieve the gradual matching of the present invention. For example, the material composition of transmission line 32 can be varied throughout its length so that the change in material can provide the gradual impedance change over the length of transmission line 32, thereby eliminating the issue of reflection and also allowing most of the actual power to go though to the laser 32. Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. For example, although several embodiments of the present invention have been described such that the impedance of the transmission line gradually decreases over its length, it can be seen that the transmission line can be configured such that the impedance gradually increases over its length in situations where the driver circuit has a lower output impedance than the input impedance of the laser. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof. | <SOH> BACKGROUND <EOH>This invention relates to a transmitter in a fiber optic system. The transmitter utilizes a transmission line that is configured to achieve optimized impedance matching without use of an impedance matching network. Fiber optic systems generally have three main components, a transmitter, a transmission medium, and a receiver. Fiber optic systems use light pulses to transmit information down fiber lines, which are then received and generally translated to electrical signals. Optical receivers generally receive and convert a modulated light signal coming from the optical fiber back into a replica of the original signal, which was applied to the transmitter. A transmitter generally includes driver circuit and an optical emitter that are electrically coupled. The optical emitter can be a laser or LED. The driver circuit receives a modulated electrical signal that contains information that is to be transmitted over the optical fiber in the form of a modulated optical signal. The driver circuit is coupled to the laser or LED and is configured to cause the light-emitting device to generate a modulated optical signal based upon the modulated electrical signal. Modern day fiber optic systems are required to be operated at increasingly high frequency rates. The frequency of the electrical signal sent from the driver circuit to the light emitter is often so high that the signal acts like a wave. Accordingly, one important consideration for driver circuits in driving light emitters in the transmitters of the fiber optic system is impedance matching of the elements. If the output of the driver circuit has different impedance than does the light emitter, signal reflections will occur. Signal reflections disturb the standing-wave oscillation and cause intersymbol interference in the light emitter that can cause significant intolerable error in the fiber optic transmission system. In order to compensate for mismatched impedance, most transmitters also include an impedance matching network that can interface the output of the driver circuit with the light emitter such that the impedance will appear matched from both the light emitter and from the driver circuit. Typically a light emitter load like a laser will have lower impedance than the output of the driver circuit. Consequently, a typical matching network will include a plurality of resistive elements that will deflect some of the signal from the light emitter so that the impedance matching and there will be no reflections. Unfortunately, these matching networks cause significant wasted energy in the system and are often difficult to place where required due to geometric restrictions. Because part of the signal goes through these matching networks so that impedance will be well matched, portions of the signal are typically going though resistors in the matching network that are parallel with the load. Some of this diverted current will release energy as heat, which is wasted energy in the system. Energy from the diverted current in the matching network that is not released as heat can instead generate electromagnetic interference, which can cause additional problems for other parts of the system. | <SOH> SUMMARY <EOH>The present invention is a transmitter for use in a fiber optic system. The transmitter includes a driver circuit, a light emitting source, and transmission lines. The driver circuit is configured to receive a modulated electrical signal and to have a driver circuit output impedance. The light emitting source has a light emitter impedance that is different than the driver circuit output impedance. The light emitting source is configured to receive the modulated electrical signal such it produces a modulated optical signal proportional to modulated electrical signal. The transmission lines are coupled between the driver circuit and the light emitting source for transmitting the modulated electrical signal from the driver circuit to the light emitting source. The transmission lines gradually change the impedance between the driver circuit and the light emitting source so as to gradually match the driver circuit output impedance to the light emitter impedance. | 20040113 | 20081007 | 20050714 | 83054.0 | 0 | SINGH, DALZID E | IMPLEMENTATION OF GRADUAL IMPEDANCE GRADIENT TRANSMISSION LINE FOR OPTIMIZED MATCHING IN FIBER OPTIC TRANSMITTER LASER DRIVERS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,756,700 | ACCEPTED | Integrated battery pack with lead frame connection | An integrated battery package, that contains semiconductor chips, for example to control and regulate battery charging and to monitor the package operation, uses a single lead frame to interconnect several internal chips, to internally connect said control chips to the battery and to connect the whole package assembly externally. The invention eliminates the need for any additional connecting mechanism. The invention uses established production processes. A molding process, similar to plastic chip encapsulation, encloses the battery controlling chips and forms at the same time the body of the battery package. An additional cover, sealed to said body, closes the battery package. | 1. An integrated battery package, comprising: one or more battery cells inside the package; one or more semiconductor chips to control the battery operation; a single lead frame, mechanically carrying said semiconductor chips and providing electrical connection to said semiconductor chips, to said battery cells inside the package as well as providing connectors to the package outside; a plastic mold, encapsulating said semiconductor chips and the inner area of said lead frame; and said plastic mold forming, at the same time, the supporting structure of said integrated battery package. 2. The assembly of claim 1 wherein some of the leads of said lead frame are preformed into a form, building the battery contacts. 3. The assembly of claim 1 wherein some of the leads of said lead frame are preformed into a form, building the external contacts of said battery package. 4. The assembly of claim 1 wherein said one or more semiconductor chips control and regulate battery charging and monitor the package operation. 5. The assembly of claim 1 wherein said one or more semiconductor chips are connected to the lead frame connectors by wire bonding. 6. The assembly of claim 1 wherein said one or more semiconductor chips are connected to the lead frame connectors with solder balls. 7. The assembly of claim 1 wherein additional passive components are mounted to said lead frame and are electrically connected to said semiconductor chip through said lead frame. 8. The assembly of claim 7 wherein said additional passive components are additional capacitors. 9. The assembly of claim 1 wherein said plastic mold, forming the supporting structure, forms the bottom part of the case of said battery package. 10. The assembly of claim 1 wherein one or more additional case elements form the top cover of the case for said battery package. 11. The assembly of claim 10 wherein said additional case elements forming the top cover of the case of said battery package, enclose all internal components and connections, including the semiconductor to battery connection, only leaving the essential external connections being exposed outside said case. 12. The assembly of claim 10 wherein said additional case elements forming the top cover of the case of said battery package are fixed and sealed to said bottom part of the case of said battery package with a sealing adhesive. 13. The assembly of claim 1 wherein said lead frame is formed to carry the external connection on opposite sides of the total package assembly. 14. The assembly of claim 1 wherein said lead frame is formed to carry the external connection on the same side of the total package assembly. 15. The assembly of claim 1 wherein said lead frame is formed to carry the external connection on the bottom side of the total package assembly. 16. A process to form an integrated battery package, comprising: providing one or more battery cells inside the package, one or more semiconductor chips to control the battery operation, a single lead frame, mechanically carrying and electrically connecting to said semiconductor chips, connecting to said battery cells inside the package and providing the connectors to the package outside, a plastic mold, encapsulating said semiconductor chips and the inner area of said lead frame and said plastic mold forming, at the same time, the supporting structure of said integrated battery package; forming some of the leads of said lead frame into a form to build the battery contacts forming some of the leads of said lead frame into a form to build the external contacts of said battery package; mounting said semiconductor chips to said lead frame; connecting said semiconductor chips to said lead frame; molding a plastic material around said semiconductor chips and the inner area of said lead frame forming, though the mechanical design of the mold, the supporting structure of said integrated battery package. 17. The process of claim 16 wherein some of the leads of said lead frame are preformed during said lead frame's production process. 18. The process of claim 16 wherein some of the leads of said lead frame are preformed in a separate bending process, but before the various chips are mounted. 19. The process of claim 16 wherein some of the leads of said lead frame are formed in a separate bending process, after the various chips are mounted and the after said molding process, encapsulating said semiconductor chips and said inner area of said lead frame. 20. The process of claim 16 wherein said lead frame is made with metal stamping. 21. The process of claim 16 wherein the lead frame is made with metal etching. 22. The process of claim 16 wherein said leads preformed into a position matching the battery contacts are welded to said battery. 23. The process of claim 16 wherein said leads preformed into a position matching the battery contacts are fixed to said battery with conductive adhesive material. 24. The process of claim 16 wherein additional passive components are mounted to said lead frame and are electrically connected to said semiconductor chip through said lead frame. 25. The process of claim 16 wherein one or more additional case elements form the top cover of the case of said battery package and enclose all internal components and connections, including the semiconductor to battery connection, only leaving the essential external connections being exposed outside said case. 26. The process of claim 25 wherein said additional case elements forming the top cover of the case of said battery package are fixed and sealed to said bottom part of the case of said battery package with a sealing adhesive. | BACKGROUND OF THE INVENTION (1) Field of the Invention This invention relates generally to a battery assembly, and more particularly to an assembly technique to incorporate electronic functions within removable battery packs, where all components are interconnected using a lead frame technology. (2) Description of Prior Art Many portable electronic devices require removable battery packs. Sometimes electronic monitoring and control functions communicating between the battery and said electronic device are incorporated within the battery pack. Usually the bare battery cells have to be mounted together with any required electronics into a sealed housing with exposed electrical contacts to connect the pack to the electronic device using it. Normally, semiconductor chips are mechanically connected to a chip-carrier, typically a lead frame in today's technology, which is then connected to a printed circuit board. Further connecting devices would then connect to said printed circuit board. A plastic case with a bottom and top element would then enclose the whole assembly Integrated semiconductor modules often use the lead frame technology to carry the semiconductor chip and to connect the chip pads with a larger printed circuit board. These lead frames are normally encapsulated with a convenient plastic material. FIG. 1 (prior art) shows the cross sections of two typical examples of said semiconductor modules. FIG. 2 shows a bare lead frame, which is produced as a long tape of metal sheet. The basic material of lead frames is sheet metal. The leads are either metal-stamped or etched to form the leads, therefore complex forms of said leads can be achieved. The leads are typically pre-formed in a bending process to accommodate all kinds of shapes. A frame area around all leads holds said leads in position, until the chips are mounted and the assembly has been encapsulated (molded) into plastic material. U.S. patent (U.S. Pat. No. 5,498,903 to Dioxin et al.) describes an integrated circuit package of the surface-mountable type within which a battery is mounted. Battery leads extend from the side of the package body opposite that which is adjacent the circuit board when mounted, and between which a conventional battery may be placed. A gap is present between the housing and the battery. The gaps thermally insulate the battery from the package body and housing, so that the circuit may be subjected to solder reflow mounting to a circuit board, while insulating the high temperature from the battery. U.S. patent (U.S. Pat. No. 6,109,530 to Larson et al.) discloses a chip-battery micro-module and fabrication there of wherein an integrated circuit “chip” is secured to a battery coin cell using various conductive and insulating layers that provide power to the chip. The chip-battery micro-module may be used to power an electronic accessory that is directly attached thereto, such as an LCD display or speaker, or to power a circuit in a smart card or electronic device such as a portable phone. The chip battery micro-module can be integrated into a plastic smart card. U.S. patent (U.S. Pat. No. 6,284,406 B1 to Xing et al) shows an IC card comprising an electronic device and a battery within a plastic card for electrically energizing the electronic device. The battery is comprised as a monolithic electrochemical cell having a lithium-containing cathode, a carbon anode, and a porous polymer separator infused with electrolyte solution. The cell has a thickness of less than 0.7 mm. The battery has an overall thickness of less than 0.8 mm. SUMMARY OF THE INVENTION A principal object of the invention described herein is to build an integrated battery package, that contains semiconductor chips, for example to control and regulate battery charging and to monitor package operation, and that interconnects several of said internal chips, connects said chips to the battery within the package and connects the whole package assembly to the outside. The basic aspects of an assembly are to reduce the connection devices to a minimum and where the package is a smooth sided box. In the disclosed invention, a single lead frame, specially designed and tailored for the envisioned task, serves several purposes: it connects the, possibly multi-chip electronic circuits, it connects the battery cells to said multichip circuit and it forms, without any additional parts, the external connectors of the completed package. A molding process, similar to some semiconductor module packaging technologies, encapsulates the inner section of the lead frame together with the assembled semiconductor chips and possibly other electrical components with plastic material into a small, probably flat, package. According to this invention, said mold is designed to form the bottom structure of the total package within that same production step. Several leads of the lead frame are pre-formed to attach to the battery cells. Two or more leads of said single lead frame are also pre-formed to finally build the external contacts. Finally, after the battery cells are mounted and connected to said lead frame, the package will be closed and sealed with a top cover, leaving only the essential external contacts being exposed outside. According to the objectives, the lead frame may internally connect one or more semiconductor chips; it may also interconnect to other active and/or passive components, like capacitors. Some of said leads of said lead frame will be formed to accommodate a connection to said battery cells and other leads will be formed to build the external connection of the final package assembly. Forming of said leads can be realized during the original manufacturing process of said lead frames or pre-forming can be processed as a separate bending process before the electronic components are mounted to said lead frame. A separate bending process can even be performed after said semiconductor and other chips are mounted to said lead frame and after the inner section of the lead frame together with said mounted chips is encapsulated. Further, according to the objectives of this invention, said molding process, encapsulating said semiconductor chips and the inner area of the lead frame, also forms the body structure of said battery package with an optimized design of said mold. The body, preferably designed as a flat structure, can also accommodate the fixture for said battery cells and form a lid to hold a top cover in place. The lead frame can be manufactured in one of several processes, for example metal stamping and metal etching. Semiconductor chips and said passive components, like capacitors, may be attached to said lead frame with a known technique, like wire bonding, solder balls, solder pads and similar established processes. After molding the inner section, the outer frame, which holds the leads in their position during the manufacturing process, is cut away. The battery cells could be electrically contacted to said leads by welding or with conductive adhesives or by similar means. The external connector may be placed on the same side or on opposites sides of the package and they may be placed in the bottom surface, parallel to the lead frame plane. Finally, to get a smooth sided box, the whole battery package will most likely be closed with an additional cover element, put over the mounted battery cells and sealed to said body of the package. The pre-formed external contacts are then the only remaining connection to the package outside. BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings, forming a material part of this description, there is shown: FIGS. 1a and 1b (Prior Art) shows a cross section of semiconductor modules, using lead frame technology. FIG. 2 (Prior Art) shows a single section of a lead frame tape as used in semiconductor packaging. FIG. 3 shows the plain lead frame, according to the disclosure invention. FIG. 4 shows said lead frame with controller and capacitor chips mounted. FIG. 5 visualizes said lead frame with mounted chips, encapsulated in a molded package. FIG. 6 shows the same molded package, forming the integrated package body, after the external frame to hold the leads in place is cut off. FIG. 7 demonstrates said integrated package body with the battery mounted on it. FIG. 8 shows the cover put over the integrated package body and battery assembly. FIG. 9 shows a cross-section of said molded body with external battery package connectors at the face side of said body. FIG. 10 shows a cross-section of said molded body with external battery package connectors at the bottom side of said body. FIG. 11 shows the basic steps of the production process. DESCRIPTION OF THE PREFERRED EMBODIMENTS A principal object of the invention described in the present document is to build an integrated battery package in a smooth sided box, that contains semiconductor chips, for example to control and regulate battery charging and to monitor package operation, and that interconnects several of said internal chips, connects said chips to the battery within the package and connects the whole package to the outside. The basic aspect is to reduce the connection devices to a minimum. The disclosed invention uses a similar lead frame technology and a similar molding technology, as used for semiconductor module packaging. In the disclosed invention, a single lead frame, specially designed for the envisioned purpose, is used. According to the invention, said lead frame serves several purposes at the same time: the first is to connect to the, possibly multi-chip electronic circuits, second, it connects the battery cells to said multichip circuit and it forms and third, without any additional parts, it builds the external connectors of the completed package. An example for such lead frame is presented in FIG. 3. Lead frames can be manufactured in one of several processes, for example metal stamping and metal etching. The outer Frame out-Frame 3 holds all leads during the manufacturing process in place. Some of said leads of said lead frame will be formed to accommodate a connection to said battery cells and other leads will be formed to build the external connection of the final package. ChipCon 3 are the connection areas where the various chips will later be contacted. pref-Lead 3 points to the preformed leads for battery cells and for external package contacts. FIG. 4, shows said lead frame with the semiconductor chips Chip and the passive components pass-Comp mounted. The semiconductor chips and said passive components, like capacitors, may be attached to said lead frame with a known technique, like wire bonding, solder balls, solder pads and similar established processes. Typical semiconductor modules encapsulate the inner section of the lead frame together with the connected chip by molding this assembly with convenient plastic material into a small, often flat, package. A similar molding concept and process is used for this invention, however additionally the mold is designed to form the bottom body of the total package in that same production step. The result of said molding process is shown in FIG. 5, the lead frame and the already mounted chips are encapsulated with a plastic material. The resulting structure will also serve as the body Body 5 of the total package. The chips are now buried inside the molded part, only said connections for battery cells Batt-Conn 5 and external connections ext-Conn 5 remain visible. Forming said leads could be realized during the original manufacturing process of said lead frames. Pre-forming can also be processed as a separate bending process before said semiconductor and other chips are mounted to said lead frame. A separate bending process can even be performed after said semiconductor and other chips are mounted to said lead frame and after the inner section of the lead frame together with said mounted chips is encapsulated by molding the lead frame and chip assembly. In a next process step after molding the body, the outer area of said lead frame is being cut away, which results in the body package as shown in FIG. 6. Only the battery connection Batt-Conn 6 and the external connectors ext-Conn 6 remain visible. All other leads, that temporarily served to hold the internal leads in place, are cut off at the points cut-Lead. Then the battery cells are mounted; a principal concept for a possible solution is presented in FIG. 7, with the body Body 7 and the battery Batt. The battery cells could be electrically contacted to said battery connection Batt-Conn 7, by welding or with conductive adhesives or by similar means. Finally as shown in FIG. 8 the cover Cover is put over the assembled body and battery Body 8 and the package may be sealed. The pre-formed external contacts ext-Conn 8 are then the only remaining connection to the package outside. The external connector may be placed, for example, on the same side or on opposites sides of the package and they may be placed in the bottom surface, parallel to the lead frame plane. FIG. 9 and FIG. 10 show two possible examples for positioning said external contacts. Sem-Chip 9 and Sem-Chip 10 are the semiconductor chips, contacted to said lead frame with solder balls Batt Conn 1 9/1 10 and Batt Conn 2 9/2 10 are the battery connection in this example; Ext Conn right is a possible solution as shown in FIG. 9; Ext Conn bottom is a similar solution as shown in FIG. 10. The production process of the integrated battery package involves several steps: in a first step 111 a flat lead frame is produced by stamping or etching or a similar process. Then in step 112 the leads for battery connection and for external connectors may be pre-formed. Now in 113 the semiconductor chips, and possibly other passive components are mounted 114. Further, in 115, the semiconductor chips and other passive components will be electrically connected to the lead frame. Then the inner section of lead frame and the mounted chips and components are encapsulated with plastic material by the molding process, step 116. The same molding process also forms the package body, 117. In the next step 118 the battery cells will be mounted and the battery contacts are welded or glued to the battery cells 119. Now close and seal the package with a top cover in the final step 120. While the invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the invention. | <SOH> BACKGROUND OF THE INVENTION <EOH>(1) Field of the Invention This invention relates generally to a battery assembly, and more particularly to an assembly technique to incorporate electronic functions within removable battery packs, where all components are interconnected using a lead frame technology. (2) Description of Prior Art Many portable electronic devices require removable battery packs. Sometimes electronic monitoring and control functions communicating between the battery and said electronic device are incorporated within the battery pack. Usually the bare battery cells have to be mounted together with any required electronics into a sealed housing with exposed electrical contacts to connect the pack to the electronic device using it. Normally, semiconductor chips are mechanically connected to a chip-carrier, typically a lead frame in today's technology, which is then connected to a printed circuit board. Further connecting devices would then connect to said printed circuit board. A plastic case with a bottom and top element would then enclose the whole assembly Integrated semiconductor modules often use the lead frame technology to carry the semiconductor chip and to connect the chip pads with a larger printed circuit board. These lead frames are normally encapsulated with a convenient plastic material. FIG. 1 (prior art) shows the cross sections of two typical examples of said semiconductor modules. FIG. 2 shows a bare lead frame, which is produced as a long tape of metal sheet. The basic material of lead frames is sheet metal. The leads are either metal-stamped or etched to form the leads, therefore complex forms of said leads can be achieved. The leads are typically pre-formed in a bending process to accommodate all kinds of shapes. A frame area around all leads holds said leads in position, until the chips are mounted and the assembly has been encapsulated (molded) into plastic material. U.S. patent (U.S. Pat. No. 5,498,903 to Dioxin et al.) describes an integrated circuit package of the surface-mountable type within which a battery is mounted. Battery leads extend from the side of the package body opposite that which is adjacent the circuit board when mounted, and between which a conventional battery may be placed. A gap is present between the housing and the battery. The gaps thermally insulate the battery from the package body and housing, so that the circuit may be subjected to solder reflow mounting to a circuit board, while insulating the high temperature from the battery. U.S. patent (U.S. Pat. No. 6,109,530 to Larson et al.) discloses a chip-battery micro-module and fabrication there of wherein an integrated circuit “chip” is secured to a battery coin cell using various conductive and insulating layers that provide power to the chip. The chip-battery micro-module may be used to power an electronic accessory that is directly attached thereto, such as an LCD display or speaker, or to power a circuit in a smart card or electronic device such as a portable phone. The chip battery micro-module can be integrated into a plastic smart card. U.S. patent (U.S. Pat. No. 6,284,406 B1 to Xing et al) shows an IC card comprising an electronic device and a battery within a plastic card for electrically energizing the electronic device. The battery is comprised as a monolithic electrochemical cell having a lithium-containing cathode, a carbon anode, and a porous polymer separator infused with electrolyte solution. The cell has a thickness of less than 0.7 mm. The battery has an overall thickness of less than 0.8 mm. | <SOH> SUMMARY OF THE INVENTION <EOH>A principal object of the invention described herein is to build an integrated battery package, that contains semiconductor chips, for example to control and regulate battery charging and to monitor package operation, and that interconnects several of said internal chips, connects said chips to the battery within the package and connects the whole package assembly to the outside. The basic aspects of an assembly are to reduce the connection devices to a minimum and where the package is a smooth sided box. In the disclosed invention, a single lead frame, specially designed and tailored for the envisioned task, serves several purposes: it connects the, possibly multi-chip electronic circuits, it connects the battery cells to said multichip circuit and it forms, without any additional parts, the external connectors of the completed package. A molding process, similar to some semiconductor module packaging technologies, encapsulates the inner section of the lead frame together with the assembled semiconductor chips and possibly other electrical components with plastic material into a small, probably flat, package. According to this invention, said mold is designed to form the bottom structure of the total package within that same production step. Several leads of the lead frame are pre-formed to attach to the battery cells. Two or more leads of said single lead frame are also pre-formed to finally build the external contacts. Finally, after the battery cells are mounted and connected to said lead frame, the package will be closed and sealed with a top cover, leaving only the essential external contacts being exposed outside. According to the objectives, the lead frame may internally connect one or more semiconductor chips; it may also interconnect to other active and/or passive components, like capacitors. Some of said leads of said lead frame will be formed to accommodate a connection to said battery cells and other leads will be formed to build the external connection of the final package assembly. Forming of said leads can be realized during the original manufacturing process of said lead frames or pre-forming can be processed as a separate bending process before the electronic components are mounted to said lead frame. A separate bending process can even be performed after said semiconductor and other chips are mounted to said lead frame and after the inner section of the lead frame together with said mounted chips is encapsulated. Further, according to the objectives of this invention, said molding process, encapsulating said semiconductor chips and the inner area of the lead frame, also forms the body structure of said battery package with an optimized design of said mold. The body, preferably designed as a flat structure, can also accommodate the fixture for said battery cells and form a lid to hold a top cover in place. The lead frame can be manufactured in one of several processes, for example metal stamping and metal etching. Semiconductor chips and said passive components, like capacitors, may be attached to said lead frame with a known technique, like wire bonding, solder balls, solder pads and similar established processes. After molding the inner section, the outer frame, which holds the leads in their position during the manufacturing process, is cut away. The battery cells could be electrically contacted to said leads by welding or with conductive adhesives or by similar means. The external connector may be placed on the same side or on opposites sides of the package and they may be placed in the bottom surface, parallel to the lead frame plane. Finally, to get a smooth sided box, the whole battery package will most likely be closed with an additional cover element, put over the mounted battery cells and sealed to said body of the package. The pre-formed external contacts are then the only remaining connection to the package outside. | 20040113 | 20080219 | 20050616 | 75904.0 | 0 | LEE, CALVIN | INTEGRATED BATTERY PACK WITH LEAD FRAME CONNECTION | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,756,781 | ACCEPTED | Method for generating natural colour satellite images | A simple and effective method is disclosed in the present invention to adjust the near natural colour of a satellite color composite to a visually more pleasing natural colour. This method includes two steps: (1) extracting vegetation “greenness” from available multispectral bands, and (2) adding (injecting) the “greenness” into the vegetation areas of the green band being displayed. | 1. A method for generating a natural colour image comprising the steps of generating a greenness band from a multispectral image including blue, green, red and near infrared bands and adjusting the green band using the greenness band. 2. A method according to claim 1 wherein the greenness band is generated mathematically using the equation: GN=(NIROrig−ROrig−λ)/s where GN is a greenness band, NIROrig is an original near infrared band, ROrig is an original red band, λ is a threshold and s is a scale factor. 3. A method according to claim 1, wherein the green band is adjusted mathematically using the equation: GAdj=GOrig+GN where GAdj is an adjusted green band, GOrig is an original green band and GN is a greenness band. 4. A method for generating a pan-sharpened natural colour image comprising the steps of generating a greenness band from pan-sharpened image bands including blue, green, red and near infrared bands and adjusting the pan-sharpened green band using the greenness band. 5. A method according to claim 4, wherein the greenness band is mathematically generated using the equation: GNH=(NIRPS−RPS−λ)/s where GNH is a high resolution greenness band, NIRPS is a pan-sharpened near infrared band, RPS is a pan-sharpened red band, λ is a threshold and s is a scale factor. 6. A method for generating a pan-sharpened natural colour image comprising the steps of generating a greenness band from a panchromatic image and a pan-sharpened red band; and adjusting the pan-sharpened green band using the greenness band. 7. A method according to claim 6, wherein the greenness band is mathematically generated using the equation: GNH=(PanOrig−RPS−λ)/s where GNH is a high resolution greenness band, PanOrig is an original panchromatic band, RPS for pan-sharpened red band, λ is a threshold and s is a scale factor. 8. A method according to claim 4, wherein the pan-sharpened green band is adjusted mathematically using the equation: GHAdg=GPS+GNH where GHAdj is an adjusted pan-sharpened green band, GPS is an pan-sharpened green band and GNH is a high resolution greenness band. 9. A method according to claim 1, wherein the greenness band is generated using an equation selected from the group comprising GN=(NIROrig−GOrig−λ)/s and GN=(NIROrig−BOrig−λ)/s, where GN is a greenness band, NIROrig is an original near infrared band, GOrig is an original green band, BOrig is an original blue band, λ is a threshold and s is a scale factor. 10. A method according to claim 1, wherein the greenness band is generated using an equation selected from the group comprising: GNH=(NIRPS−GPS−λ)/s and GNH=(NIRPS−BPS−λ)/s, where GNH is a high resolution greenness band, NIRPS is a pan-sharpened near infrared band, GPS is a pan-sharpened green band, BPS is a pan-sharpened blue band, λ is a threshold and s is a scale factor. 11. A method according to claim 1 , wherein the greenness band is generated using an equation selected from the group comprising: GNH=(PanOrig−GPS−λ)/s and GNH=(PanOrig−BPS−λ)/s, where GNH is a high resolution greenness band, PanOrig is an original panchromatic band, GPS for pan-sharpened green band, BPS for pan-sharpened blue band, λ is a threshold and s is a scale factor. 12. A method according to claim 7, wherein the greenness bands are generated using an equation selected from the group comprising: GNH=(PanOrig−GPS−λ)/s and GNH=(PanOrig−BPS−λ)/s, where GNH is a high resolution greenness band, PanOrig is an original panchromatic band, GPS for pan-sharpened green band, BPS for pan-sharpened blue band, λ is a threshold and s is a scale factor. | CROSS REFERENCE TO RELATED APPLICATIONS This application claims priority from U.S. Provisional Patent application Ser. No. 60/440,636 filed Jan. 17, 2003. FIELD OF THE INVENTION This invention relates to the field of image processing and in particular a method of generating natural colour satellite images. BACKGROUND OF THE INVENTION Generally, the blue, green and red bands of multispectral satellite sensors do not cover the whole blue, green and red wavelength ranges, respectively. As a result, the “natural” colour composites from the blue, green and red bands do not reproduce natural colours as found in the nature or on a colour photo. Such colour is near natural colour, but still noticeably unnatural. In order to achieve a better visual effect, it is useful to adjust, either manually or automatically, the near natural colour to a more natural colour. Such a colour adjustment is useful in many applications, such as colour image mapping, GIS integration, image visualization, and other purposes. The most representative ground covers on the Earth's surface are vegetation, water and soil (e.g., surface not covered by vegetation or water). Their general spectral reflectance in different spectral ranges is characterized in FIG. 1. Vegetation curves have a peak in the green range compared to the blue and red ranges. The spectral curves of soil reflectance rise proportional to the wavelength. However, the curve of clear water usually has a peak in blue range and then descends proportional to the wavelength. Therefore, when the blue, green and red bands of a multispectral sensor are displayed with blue, green and red colour, a near natural colour composite can be generated with water shown in blue, vegetation shown in green and soil shown in light yellow grey or light red grey). But, the colour of vegetation often does not show up as a natural green. This makes colour composites look unnatural and not visually pleasing. SUMMARY OF THE INVENTION The invention relates to a method for generating a natural colour image comprising the steps of generating a greenness band from a multispectral image including blue, green, red and near infrared bands and adjusting the green band using the greenness band. In another embodiment, the invention relates to a method for generating a pan-sharpened natural colour image comprising the steps of generating a greenness band from pan-sharpened image bands including blue, green, red and near infrared bands and adjusting the pan-sharpened green band using the greenness band. In another embodiment, the invention relates to a method for generating a pan-sharpened natural colour image comprising the steps of generating a greenness band from a panchromatic image and a pan-sharpened red band; and adjusting the pan-sharpened green band using the greenness band. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a graph showing general spectral reflectance curves of soil, water and vegetation with general spectral ranges of individual multispectral bands; and FIG. 2 is a diagram showing spectral ranges of the multispectral bands and panchromantic band from individual satellites. A simple and effective method is disclosed in the present invention to adjust the near natural colour of a satellite colour composite to a visually more pleasing natural colour. This method includes two steps: (1) extracting vegetation “greenness” from available multispectral bands, and (2) adding (injecting) the “greenness” into the vegetation areas of the green band being displayed. In this way the vegetation areas can be made to look greener and fresher, so that the whole image appears more natural. This method can be used to adjust the near natural colour of original multispectral composites and that of pan-sharpened composites. Adjusting the Colour of Original Near Natural Colour Composites For a near natural colour composite with original multispectral bands, the vegetation “greenness” can be extracted using the equation: GN=(NIROrig−ROrig−λ)/s (1) where GN is a greenness band, NIROrig is an original near infrared band, ROrig is an original red band, λ is a threshold and s is a scale factor. From FIG. 1 it can be seen that the vegetation reflectance is very high in near infrared range and very low in red range. Consequently, vegetation covers have very high grey values in near infrared (NIR) band and low grey values in red (R) band. The subtraction of NIR band by R band (NIROrig-ROrig) results in a subtraction band with high grey values in vegetation areas (because of large grey value difference between the NIR and R bands), low grey values in soil areas, and negative grey values in water areas. To make sure that the colour adjustment just happens to vegetation areas, a threshold λ needs to be introduced to segment non-vegetation areas in the subtraction band from vegetation areas, and then the non-vegetation areas need to be assigned with a grey value of zero. After this segmentation and assignment, only vegetation areas in the subtraction band contain grey values larger than zero, while other areas are all set to zero, resulting in a greenness band. The threshold can be identified manually and automatically. Some segmentation methods can be adopted for the segmentation, for example, the methods introduced by Parker J. R. (1997) [Algorithms for Image Processing and Computer Vision, John Wiley & Sons, New York, Chichester, 417 p.]. To control the magnitude of the greenness, a scale factor s can be introduced. Alternative methods can be used to generate the greenness band. Instead of using the original red band (ROrig), the original green or blue band can be used to replace the red band (ROrig) in equation (1). This replacement also can results in a greenness band with high grey values in vegetation areas and zero grey value in other areas. After the greenness band is generated, the greenness can be added (or injected) into the vegetation areas of the green band to adjust the green colour of the near natural colour composite: GAdj=GOrig.+GN (2) where GAdj is an adjusted green band, GOrig is an original green band and GN is a greenness band. For the improved natural colour image display, original blue band, adjusted green band, and original red band are displayed with blue, green and red colour, respectively. Adjusting the Colour of Pan-Sharpened Near Natural Colour Composites A similar method can be applied to improve the natural colour display of pan-sharpened colour composites. However, pan-sharpened near infrared and red bands need to be used to generate a high resolution greenness band: GNH=(NIRPS−RPS−λ)/s (3) where GNH is a high resolution greenness band, NIRPS is a pan-sharpened near infrared band, RPS is a pan-sharpened red band, λ is a threshold and s is a scale factor. An alternative for generating a high resolution greenness band is, instead of using pan-sharpened near infrared band, the high resolution panchromatic band can be used. This alternative also results in very good results. The method for extracting the high resolution greenness can be described as: GNH=(PanOrig−RPS−λ)/s (4) where GNH is a high resolution greenness band, PanOrig is an original panchromatic band, RPS for pan-sharpened red band, λ is a threshold and s is a scale factor. From FIG. 2 it can be seen that the panchromatic bands of IKONOS, QuickBird and Landsat 7 cover a broad spectral range including near infrared. The average spectral reflectance of vegetation for this broad range is not as high as in near infrared range, but it is still significantly higher than the average reflectance of soil and water for the same range (see FIG. 1). Therefore, vegetation is usually brighter than soil and water in such panchromatic images. The subtraction of PanOrig band by RPS band (PanOrig-RPS) results in high grey values in vegetation areas, very low grey values in soil areas and water areas. A threshold λ is also needed to segment non-vegetation areas from vegetation areas to set the grey values of non-vegetation areas to zero. After this segmentation, only vegetation areas of the subtraction band contain grey values higher than zero, while other areas are zero, resulting in a high resolution greenness band (GNH). A scale factor s can be introduced to adjust the magnitude of the greenness. Other variations for generating greenness bands or high-resolution greenness bands exist. For example, subtraction of near infrared band by green band or blue band and subtraction of green band by blue or red band can also generate greenness bands. For high resolution greenness bands, pan-sharpened bands need to be involved. The subtraction of original panchromatic band by pan-sharpened green or blue band can also result in a high resolution greenness band. However, the greenness bands generated with equations (1) (3) or (4) are more effective for improving the natural colour visualization of multispectral satellite images. After the high resolution greenness band is generated, the greenness can be added (or injected) into the vegetation areas of the pan-sharpened green band to adjust the green colour of the pan-sharpened near natural colour composite: GHAdj=GPS+GNH (5) where GHAdj is an adjusted high resolution green band, GPS is a pan-sharpened green band and GNH is a high resolution greenness band. For the display of the improved natural colour image, pan-sharpened blue band, adjusted high resolution green band, and pan-sharpened red band are displayed with blue, green and red colour, respectively. In a preferred embodiment of the invention, the methods of the present invention are implemented by a programmed computer, and the method is used as a computer program product comprising a software tool stored on a machine-readable medium such as a CD Rom or floppy disc. | <SOH> BACKGROUND OF THE INVENTION <EOH>Generally, the blue, green and red bands of multispectral satellite sensors do not cover the whole blue, green and red wavelength ranges, respectively. As a result, the “natural” colour composites from the blue, green and red bands do not reproduce natural colours as found in the nature or on a colour photo. Such colour is near natural colour, but still noticeably unnatural. In order to achieve a better visual effect, it is useful to adjust, either manually or automatically, the near natural colour to a more natural colour. Such a colour adjustment is useful in many applications, such as colour image mapping, GIS integration, image visualization, and other purposes. The most representative ground covers on the Earth's surface are vegetation, water and soil (e.g., surface not covered by vegetation or water). Their general spectral reflectance in different spectral ranges is characterized in FIG. 1 . Vegetation curves have a peak in the green range compared to the blue and red ranges. The spectral curves of soil reflectance rise proportional to the wavelength. However, the curve of clear water usually has a peak in blue range and then descends proportional to the wavelength. Therefore, when the blue, green and red bands of a multispectral sensor are displayed with blue, green and red colour, a near natural colour composite can be generated with water shown in blue, vegetation shown in green and soil shown in light yellow grey or light red grey). But, the colour of vegetation often does not show up as a natural green. This makes colour composites look unnatural and not visually pleasing. | <SOH> SUMMARY OF THE INVENTION <EOH>The invention relates to a method for generating a natural colour image comprising the steps of generating a greenness band from a multispectral image including blue, green, red and near infrared bands and adjusting the green band using the greenness band. In another embodiment, the invention relates to a method for generating a pan-sharpened natural colour image comprising the steps of generating a greenness band from pan-sharpened image bands including blue, green, red and near infrared bands and adjusting the pan-sharpened green band using the greenness band. In another embodiment, the invention relates to a method for generating a pan-sharpened natural colour image comprising the steps of generating a greenness band from a panchromatic image and a pan-sharpened red band; and adjusting the pan-sharpened green band using the greenness band. | 20040114 | 20080527 | 20050428 | 70449.0 | 0 | SHIKHMAN, MAX | METHOD FOR GENERATING NATURAL COLOUR SATELLITE IMAGES | SMALL | 0 | ACCEPTED | 2,004 |
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10,756,817 | ACCEPTED | Methods and apparatus for femoral and tibial resection | Methods and apparatus for femoral and tibial resection, including positioning and alignment guides, cutting guides, cutting tools and techniques for same. | 1. Apparatus for adjustably positioning surgical instrumentation relative to bone, comprising: a. a structural member adapted to fasten to bone; b. surgical instrumentation adapted to guide surgical devices; and c. an alignment module, comprising: i. a structural member retention component adapted to connect to the structural member; ii. a surgical instrumentation retention component adapted to connect to the surgical instrumentation; iii. an intermediate component adapted to connect to the structural member retention component in a fashion that allows the structural member retention component and the intermediate component to rotate relative to each other about at least one axis, and adapted to connect to the surgical instrumentation retention component in a fashion that allows the surgical instrumentation retention component and the intermediate component to rotate relative to each other about at least one axis; iv. an adjustment mechanism connecting the intermediate component and the structural member retention component, the adjustment mechanism adapted to control and fix orientation of the intermediate component relative to the structural member retention component; and v. an adjustment mechanism connecting the intermediate component and the surgical instrumentation retention component, the adjustment mechanism adapted to control and fix orientation of the intermediate component and the surgical instrumentation retention component. 2. A process for conducting knee surgery, comprising: a. exposing bones in the vicinity of the knee joint; b. fastening a rod to bone in the vicinity of the knee joint in a manner intended at least coarsely to align the rod to a desired axis relative to the bone; c. attaching a rod retention component of an alignment module to the rod, the alignment module comprising: i. a rod retention component adapted to connect to the rod; ii. a surgical instrumentation retention component adapted to connect to surgical instrumentation; iii. an intermediate component adapted to connect to the rod retention component in a fashion that allows the rod retention component and intermediate component to rotate relative to each other about at least one axis, and adapted to connect to the surgical instrumentation retention component in a fashion that allows the surgical instrumentation retention component and the intermediate component to rotate relative to each other about at least one axis; iv. an adjustment mechanism connecting the intermediate component and the rod retention component, the adjustment mechanism adapted to control and fix orientation of the intermediate component relative to the rod retention component; and v. an adjustment mechanism connecting the intermediate component and the surgical instrumentation retention component, the adjustment mechanism adapted to control and fix orientation of the intermediate component and the surgical instrumentation retention component; d. attaching instrumentation to the alignment module; e. adjusting at least one of the adjustment mechanisms in order to finely align the instrumentation relative to the bone; f. resecting bone using the instrumentation; g. attaching a surgical implant to the resected bone; h. reassembling the knee; and i. closing the exposed knee. 3. A mill guide instrument for guiding a tissue cutting mill, the mill guide instrument comprising: a guide body comprising a distal section adapted to fit into a bore in a bone and a template section having a guide surface; and a mill guide selectively mounted on the guide body and adapted to engage the tissue cutting mill, the mill guide comprising a stylus configured to selectively follow the guide surface of the template such that the mill guide orients the tissue cutting mill towards tissue to be removed from the bone to form a bone cavity. 4. A mill guide instrument for cutting a cavity in bone comprising: a guide body comprising a distal section dimensioned to fit into a bore in a bone and a template section having a guide surface; a mill guide being rotationally connected to the guide body, the mill guide comprising a stylus and a sleeve; a mill being slidably received within the sleeve, the mill having a proximal section, distal section and a shaft extending therebetween, the mill being oriented toward tissue to be removed when the stylus selectively follows the guide surface of the template section. 5. A method of using a mill guiding instrument for guiding a tissue cutting tool, the method comprising: inserting a guide body into a bore in a bone; attaching a template section with a guide surface to the guide body; attaching a mill guide with a stylus to the guide body; activating the mill with a cutting tip positioned to remove bone tissue; and following the guide surface of the template section with the stylus until the cavity is prepared to accept prosthesis. 6. A mill guiding instrument for cutting a cavity in bone, comprising: a support frame having a distal portion adapted to be received within the bone; a mill guide connected to the support frame and having a stylus; a mill adapted to cut tissue and adapted to rotate within the mill guide; a template connected to the support frame and having a guide surface comprised of a three-dimensional surface, tracing the template with the stylus causing the mill guide to position the mill such that a desired cavity is cut into the bone. 7. A cutting jig for preparing a bone to receive an implant comprising: a shaft having a portion insertable in a medullary canal of the bone for coupling the cutting jig to the bone; a length adjustment member slidable on the shaft to vary the length adjustment member location with respect to the shaft; an arm extending laterally from the length adjustment member; an extension extending from a lateral end of the arm; and a cutting guide located on an end of the extension. 8. An instrument for resecting the distal femur, comprising: a plurality of cutting guide blocks, each of said plurality of cutting guide blocks having an anterior cutting guide surface defining three points, a posterior cutting guide surface defining three points, an anterior chamfer guide surface defining three points, a posterior chamfer guide surface defining three points, and a distal cutting guide surface defining three points; a pair of positioning fixtures, for positioning one of said cutting guide blocks on the distal femur; an alignment assembly for positioning said pair of positioning fixtures; a drill guide cooperating with said alignment assembly for drilling holes in the distal femur for attaching said pair of positioning fixtures to the distal femur; and a sizing boom attachable to said alignment assembly for selecting said one cutting guide block from said plurality of cutting guides, said sizing boom including an adjustable stylus for contacting the most prominent aspect of the anterior lateral cortex to determine the appropriate size for said one cutting guide. 9. A method of resecting a bone during arthroplasty using a resection guide, said method comprising: aligning the resection guide relative to the bone in three degrees of freedom, at least one of said degrees of freedom being rotational; locking the resection guide in position; and resecting the bone using the resection guide, wherein said step of aligning includes moving the resection guide through an infinitely adjustable range. 10. A method according to claim 9, further comprising anchoring a pin to the bone, and coupling the resection guide to said pin via an alignment guide. 11. A method according to claim 10, wherein said locking of the resection guide comprises locking said alignment guide in each of said three degrees of freedom. 12. A method according to claim 9, wherein said locking of the resection guide includes pinning said resection guide to the bone. 13. A method according to claim 9, wherein said resecting the bone using the resection guide does not require the removal from the bone of any part of the resection guide prior to resection. 14. A method of resecting a bone during arthroplasty using a resection guide, said method comprising: aligning the resection guide relative to the bone in three degrees of freedom, at least one of said degrees of freedom being rotational; locking the resection guide in position; and resecting the bone using the resection guide, wherein said method is adapted for resecting both the femur and the tibia. 15. A method according to claim 14, further comprising: coupling an EM rod to the resection guide; and using the EM rod to perform the aligning of the resection guide. 16. A method of resecting a bone during arthroplasty using a resection guide, said method comprising: aligning the resection guide relative to the bone in three degrees of freedom, at least one of said degrees of freedom being rotational; locking the resection guide in position; and resecting the bone using the resection guide, wherein no part of the resection guide needs to be removed from the bone prior to resection. 17. A method according to claim 16, further comprising: coupling an EM rod to the resection guide; and using the EM rod to perform the step of aligning the resection guide. 18. A method of locating a resection guide for resecting a bone during arthroplasty, said method comprising: aligning the resection guide relative to the bone in three degrees of freedom, at least one of said degrees of freedom being rotational; and locking the resection guide in position, wherein said aligning includes moving the resection guide through an infinitely adjustable range. 19. A method according to claim 18, further comprising: coupling an EM rod to the resection guide; and using the EM rod to perform the aligning of the resection guide. 20. A method according to claim 18, wherein said resection guide does not need to be removed from any part of the bone prior to resection. 21. A method according to claim 18, wherein said method is adapted for resecting both the femur and the tibia. 22. A method according to claim 18, wherein said resection guide does not need to be removed from any part of the bone prior to resection and said method is adapted for resecting both the femur and the tibia. 23. A method of locating a resection guide for resecting a bone during arthroplasty, said method comprising: aligning the resection guide relative to the bone in three degrees of freedom, at least one of said degrees of freedom being rotational; and locking the resection guide in position, wherein said method is adapted for resecting both the femur and the tibia. 24. A method according to claim 23, further comprising: coupling an EM rod to the resection guide; and using the EM rod to perform the aligning of the resection guide. 25. A method of locating a resection guide for resecting a bone during arthroplasty, said method comprising: aligning the resection guide relative to the bone in three degrees of freedom, at least one of said degrees of freedom being rotational; and locking the resection guide in position, wherein no part of the resection guide needs to be removed from the bone prior to resection. 26. A method according to claim 25, further comprising: coupling an EM rod to the resection guide; and using the EM rod to perform the aligning of the resection guide. 27. A method for aligning a resection guide relative to a patient's bone during arthroplasty, said method comprising: coupling an alignment guide to a patient's bone; coupling a resection guide to said alignment guide; and positioning said resection guide along a translational path and along a plurality of rotational paths by manipulating said alignment guide. 28. A method according to claim 27, wherein said plurality of rotational paths comprise a first rotational path and a second rotational path. 29. A method according to claim 28, wherein said first and second rotational paths are about different axes. 30. A method according to claim 29, wherein said axes are transverse to each other. 31. A method according to claim 27, further including attaching an anchoring pin to a patient's bone and securing said alignment guide thereto. 32. A method according to claim 27, further including locking said alignment guide along said translational path and about a first and second one of said plurality of rotational paths. 33. A method for aligning a resection guide relative to a patient's bone during arthroplasty, said method comprising: coupling an alignment guide to a patient's bone; coupling a resection guide to said alignment guide; and aligning said resection guide relative to the bone in three degrees of freedom by manipulation of the alignment guide, at least one of said degrees of freedom being rotational. 34. Instrumentation for intramedullary alignment for femoral instruments in minimally invasive unicompartmental knee replacement surgery, said instrumentation comprising: an intramedullary rod for insertion in the intramedullary canal of a femur; a resection block for fixation to the femur with the knee in flexion, said resection block having a planar slot for receiving a cutting member to establish a planar surface along a posterior aspect of a femoral condyle of the femur and a channel extending through said resection block in a medial-lateral direction parallel to said slot; and a linking instrument comprising a vertical linking bar and a horizontal linking bar extending from said vertical linking bar at an angle, said horizontal linking bar being receivable in said channel to couple said linking instrument to said resection block to form a one-piece construct, said vertical linking bar being mountable to said intramedullary rod in a perpendicular orientation thereto couple said construct to said intremedullary rod. | RELATED APPLICATIONS This application is a continuation of co-pending U.S. application Ser. No. 09/799,325 filed Mar. 5, 2001, which is a continuation-in-part of U.S. application Ser. No. 09/261,528, filed Mar. 3, 1999, now U.S. Pat. No. 6,197,064, which was a continuation of U.S. application Ser. No. 08/892,286, now U.S. Pat. No. 5,879,354, which was a divisional of U.S. application Ser. No. 08/649,465, filed May 17, 1996, now U.S. Pat. No. 5,755,803, which was a continuation-in-part application of U.S. application Ser. No. 08/603,582, filed Feb. 20, 1996, now U.S. Pat. No. 5,810,827, which was a continuation-in-part application of U.S. application Ser. No. 08/300,379, filed Sep. 2, 1994, now U.S. Pat. No. 5,514,139, dated May 7, 1996, and which was also a continuation-in-part application of U.S. application Ser. No. 08/479,363, now U.S. Pat. No. 5,643,272, which is a continuation-in-part of U.S. application Ser. No. 08/342,143, filed Nov. 18, 1994, now U.S. Pat. No. 5,597,379, which is a continuation-in-part application of U.S. application Ser. No. 08/300,379, filed Sep. 2, 1994, now U.S. Pat. No. 5,514,139, dated May 7, 1996. U.S. Ser. No. 479,363. The entire disclosures of these related applications are expressly incorporated herein by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention generally relates to methods and apparatus for femoral and tibial resection to allow for the interconnection or attachment of various prosthetic devices. 2. Related Art Different methods and apparatus have been developed in the past to enable a surgeon to remove bony material to create specifically shaped surfaces in or on a bone for various reasons including to allow for attachment of various devices or objects to the bone. Keeping in mind that the ultimate goal of any surgical procedure is to restore the body to normal function, it is critical that the quality and orientation of the cut, as well as the quality of fixation, and the location and orientation of objects or devices attached to the bone, is sufficient to ensure proper healing of the body, as well as appropriate mechanical function of the musculoskeletal structure. In total knee replacements, a series of planar and/or curvilinear surfaces, or “resections,” are created to allow for the attachment of prosthetic or other devices to the femur, tibia and/or patella. In the case of the femur, it is common to use the central axis of the femur, the posterior and distal femoral condyles, and/or the anterior distal femoral cortex as guides to determine the location and orientation of distal femoral resections. The location and orientation of these resections are critical in that they dictate the final location and orientation of the distal femoral implant. It is commonly thought that the location and orientation of the distal femoral implant are critical factors in the success or failure of the artificial knee joint. Additionally, with any surgical procedure, time is critical, and methods and apparatus that can save operating room time, are valuable. Past efforts have not been successful in consistently and/or properly locating and orienting distal femoral resections in a quick and efficient manner. The use of oscillating sawblade based resection systems has been the standard in total knee replacement for over 30 years. Due to their use of this sub-optimal cutting tool, the instrumentation systems all possess certain limitations and liabilities. Perhaps the most critical factor in the clinical success of TKA is the accuracy of the implant's placement. This can be described by the degrees of freedom associated with each implant; for the femoral component these include location and orientation that may be described as Varus-Valgus Alignment, Rotational Alignment, Flexion-Extension Alignment, A-P location, Distal Resection Depth Location, and Mediolateral Location. Conventional instrumentation very often relies on the placement of ⅛ or {fraction (3/16)} inch diameter pin or drill placement in the anterior or distal faces of the femur for placement of cutting guides. In the case of posterior referencing systems, the distal resection cutting guide is positioned by drilling two long drill bits into the anterior cortex. As these long drills contact the oblique surface of the femur they very often deflect, following the path of least resistance into the bone. As the alignment guides are disconnected from these cutting guides, the drill pins will “spring” to whatever position was dictated by their deflected course thus changing their designated, desired alignment to something less predictable and/or desirable. This kind of error is further compounded by the “tolerance stacking,” inherent in the use of multiple alignment guides and cutting guides. Another error inherent in these systems further adding to mal-alignment is deflection of the oscillating sawblade during the cutting process. The use of an oscillating sawblade is very skill intensive as the blade will also follow the path of least resistance through the bone and deflect in a manner creating variations in the cut surfaces which further contribute to prosthesis mal-alignment as well as poor fit between the prosthesis and the resection surfaces. Despite the fact that the oscillating saw has been used in TKA for more than 30 years, orthopedic salespeople still report incidences where poor cuts result in significant gaps in the fit between the implant and the bone. It is an often repeated rule of thumb for orthopedic surgeons that a “Well placed, but poorly designed implant will perform well clinically, while a poorly placed, well designed implant will perform poorly clinically.” One of the primary goals of the invention described herein is to eliminate errors of this kind to create more reproducible, consistently excellent clinical results in a manner that requires minimal manual skill on the part of the surgeon. None of the previous efforts of others disclose all of the benefits and advantages of the present invention, nor do the previous efforts of others teach or suggest all the elements of the present invention. OBJECTS AND SUMMARY OF THE INVENTION Many of the specific applications of the method and apparatus of the present invention described herein apply to total knee replacement, a surgical procedure wherein planar surfaces and/or curvilinear surfaces must be created in or on bone to allow for proper attachment or implantation of prosthetic devices. However, it should be noted that it is within the scope of the present invention to apply the methods and apparatus herein described to the removal of any kind of material from bones in any other application where it is necessary, desirable or useful to remove material from bones. The apparatus of the present invention comprises a number of components including a positioning apparatus, a pattern apparatus and a cutting apparatus. The pattern apparatus is oriented and located by the use of the positioning apparatus which references the geometry of a bone to be resected and/or other anatomic landmarks. When used to resect a distal femur, the positioning apparatus also references the long axis of the femur. Once the positioning apparatus has been properly located, aligned, and initially fixed in place, the pattern apparatus may be attached thereto, and then adjusted according to the preferences of the surgeon utilizing the apparatus, and then the pattern apparatus can be rigidly fixed to a bone to be resected. This ensures the pattern apparatus is properly located and oriented prior to the use of the cutting apparatus to remove material from the bone. More specifically, when the method and apparatus of the present invention are used in connection with resecting a distal femur, the positioning apparatus is located and aligned utilizing the intramedullary canal of the femur, (thereby approximating the long axis of the femur), the distal surfaces of the femoral condyles, the anterior surface of the distal femur, and the posterior surfaces of the femoral condyles, which are referenced to indicate the appropriate location and orientation of the pattern apparatus. Fixation means may be used to fix the positioning apparatus, as well as the pattern apparatus to the distal femur. Means may be present in the positioning apparatus and/or pattern device for allowing the following additional adjustments in the location and orientation of the pattern device: 1. internal and external rotational adjustment; 2. varus and valgus angular adjustment; 3. anterior and posterior location adjustments; 4. proximal and distal location adjustment; and 5. flexion and extension angular adjustment. Cannulated screws, fixation nails or other fixation means may then be used to firmly fix the pattern apparatus to the distal femur. The positioning apparatus may then be disconnected from the pattern apparatus and removed from the distal femur. Thus, the location and orientation of the pattern apparatus is established. The pattern device possesses slot-like features, or a cutting path, having geometry that matches or relates to the desired geometry of the cut. When used in connection with resecting a knee, the cutting path resembles the interior profile of the distal femoral prosthesis. The cutting path guides the cutting apparatus to precisely and accurately remove material from the distal femur. Thus, the distal femur is thereby properly prepared to accept a properly aligned and located distal prosthesis. In preparing a patella, the pattern device may be an integral part of the positioning apparatus which is oriented and located by referencing the geometry of the patella itself as well as the structures of the patellofemoral mechanism to determine the location and orientation of a predominantly planar resection. The cutting device may then be employed to perform the resection of the patella by traversing the path dictated by the pattern device, thus dictating the final location and orientation of the patella prosthesis. The apparatus of the present invention comprises a number of components including an ankle clamp, an alignment rod, a fixation head, cutting guide clamps having an integral attachment mechanism, and a milling bit. The method of present invention includes the steps of attaching the ankle clamp about the ankle, interconnecting the distal end of the alignment rod with the ankle clamp, interconnecting the fixation head with the proximal end of the alignment rod, partially attaching the fixation head to the proximal tibia, aligning the alignment rod, completely attaching the fixation head to the proximal tibia, interconnecting the cutting guide clamps with the alignment rod, positioning the cutting guide clamps about the proximal tibia, securing the cutting guide clamps to the tibia at a proper location, removing the fixation head, and cutting the proximal tibia with the milling bit. The implant of the present invention has an outer bearing surface and an inner attachment surface. The outer bearing surface functions as a joint contact surface for the reconstructed bone. The inner attachment surface contacts a bone and is attached thereto. The inner attachment surface of the implant is curvilinear from an anterior to a posterior area of the femur, as is conventionally known, and is also curvilinear from a medial to a lateral area of the femur to approximate the shape of natural femur. The resection of the femur for accommodating the implant can be properly performed by a milling device employing one or more curvilinear milling bits. There are numerous advantages associated with the curvilinear implant of the present invention. First, it will allow for a very thin implant cross-section and therefore necessitate the removal of the least amount of viable osseous tissue. Accordingly, the kinematics of the artificial joint could be made to be as close as possible to that of a healthy, natural knee joint. In addition, the curvilinear geometry of the implant dramatically decreases the stress risers inherent in conventional rectilinear femoral implants and allows for a thinner cross-sectional geometry while potentially increasing the resistance of the implant to mechanical failure under fatigue or impact loading. Conversely, the curvilinear geometry of the implant may also allow for an advantageous reduction in the flexural rigidity of the implant which may result in avoidance of the “stress-shielding” inherent in rigid implant designs. This curvilinear implant of the present invention could also result in a less expensive femoral implant because of the reduced amount of material needed for the implant, as well as an improved, more natural, and even stronger knee replacement. The cross-section of the implant could be varied to assist in seating the implant and to increase the strength and fit of the implant. The implants of the present invention having curvilinear implant surfaces could be fabricated of metal, plastic, or ceramic or any other material. Further, the thickness of the implants and the material required to fabricate the implant could be reduced as the implants are adapted to increasingly curvilinear surfaces. The resected surfaces of a femur or other bone to accept the implant of the present invention could be prepared by the apparatus and method for resection shown and described in the prior related applications set forth herein, the entire disclosures of which are expressly incorporated herein by reference. The apparatus of the present invention comprises a number of components including a positioning and drill guide, a cutting guide and a cutting apparatus. The drill guide is used to create holes in the medial and lateral sides of the femur that correspond to the fixation features of the cutting guide. The cutting guide is oriented and located by inserting fixation nubs connected to the cutting guide into the medial and lateral holes in the femur. The cutting guide can then be further affixed to the femur. The cutting apparatus can then be used with the cutting guide to resect the femur. A conventional cutting block used with a conventional oscillating saw can also be positioned and interconnected with a femur in a similar manner using the drill guide of the present invention to create medial and lateral holes. A cutting guide can then be attached to the holes. A conventional cutting block can be interconnected with the cutting guide for attachment of the block to the femur. This invention can also be used in connection with a cortical milling system, i.e., a cutting system for providing a curvilinear cutting path and curvilinear cutting profile. Likewise, a tibial cutting guide can similarly be positioned on a tibia with a drill guide. It is a primary object of the present invention to provide an apparatus for properly resecting the distal human femur. It is also an object of this invention to provide an apparatus for properly orienting a resection of the distal human femur. It is an additional object of the resection apparatus of the present invention to properly locate the resection apparatus with respect to the distal human femur. It is even another object of the resection apparatus of the present invention to properly orient the resection apparatus with respect to the distal human femur. It is another object of the resection apparatus of the present invention to provide a guide device for establishing the location and orientation of the resection apparatus with respect to the distal human femur. It is still a further object of the resection apparatus of the present invention to lessen the chances of fatty embolisms. It is even a further object of this invention is to provide a resection apparatus capable of forming some or all of the resected surfaces of the distal human femur. It is another object of the resection apparatus of the present invention to provide an apparatus which is simple in design and precise and accurate in operation. It is also an intention of the resection apparatus of the present invention to provide a guide device for determining the location of the long axis of the femur while lessening the chances of fatty embolism. It is also an object of the resection apparatus of the present invention to provide a device to physically remove material from the distal femur in a pattern dictated by the pattern device. It is even another object of the resection apparatus of the present invention to provide a circular cutting blade for removing bone from the distal human femur to resection the distal human femur. It is also an object of the present invention to provide a method for easily and accurately resecting a distal human femur. These objects and others are met by the resection method and apparatus of the present invention. It is a primary object of the present invention to provide methods and apparatus for femoral and tibial resection. It is another object of the present invention to provide a method and apparatus for properly, accurately and quickly resecting a bone. It is also an object of this invention to provide a method and apparatus for properly orienting and locating a resection of a bone. It is a further object of the present invention to provide a method and apparatus to properly locate and orient the resection apparatus with respect to a bone. It is another object of the present invention to provide methods and apparatus for femoral and tibial resection which are simple in design and precise and accurate in operation. It is an additional object of the present invention to provide a method and apparatus to physically remove material from a bone in a pattern dictated by a pattern device and/or the geometry of a cutting device. It is a further object of the present invention to provide methods and apparatus for resecting a bone which allows one to visually inspect the location of the cut or cuts prior to making the cut or cuts. It is yet a further object of the present invention to provide a method and apparatus for resecting a bone which physically removes material from the bone along a surface dictated by a guide device. It is still a further object of the present invention to provide a method and apparatus for resecting a bone which employs a milling bit or form cutter for removing material from the bone. It is a further object of the present invention to provide methods and apparatus for femoral and tibial resection wherein the apparatus can be located on a bone to be cut in a quick, safe and accurate manner. It is a primary object of the present invention to provide a method and apparatus for properly resecting the proximal human tibia in connection with knee replacement surgery. It is also an object of the present invention to provide a method and apparatus for resecting the proximal human tibia which minimizes the skill necessary to complete the procedure. It is another object of the present invention to provide a method and apparatus for resecting the proximal human tibia which properly orients the resection of the proximal tibia. It is even another object of the present invention to provide a method and apparatus for resecting the proximal human tibia which is easy to use. It is yet another object of the present invention to provide a method and apparatus for resecting the proximal human tibia which orients the resection in accordance with what is desired in the art. It is still yet another object of the present invention to provide a method and apparatus for resecting the proximal human tibia which minimizes the amount of bone cut. It is a further object of the present invention to provide a method and apparatus for resecting the proximal human tibia which allows one to visually inspect the location of the cut prior to making the cut. It is even a further object of the present invention to provide a method and apparatus for resecting the proximal human tibia which is simple in design and precise and accurate in operation. It is yet a further object of the present invention to provide a method and apparatus for resecting the proximal human tibia which physically removes material from the proximal tibia along a surface dictated by a guide device. It is still a further object of the present invention to provide a method and apparatus for resecting the proximal human tibia which employs a milling bit for removing material from the proximal tibia. It is also an object of the present invention to provide a method and apparatus for resecting the proximal human tibia which includes a component which is operated, and looks and functions, like pliers or clamps. It is even another object of the present invention to provide an alternate embodiment of the method and apparatus for resecting the proximal human tibia which includes a component that resembles a U-shaped device for placing about the tibia. It is even a further object of the present invention to provide an alternate embodiment of the method and apparatus for resecting the proximal human tibia which includes a component that resembles an adjustable, square, U-shaped device for placing about the tibia. These objects and others are met and accomplished by the method and apparatus of the present invention for resecting the proximal tibia. It is a primary object of the present invention to provide a method and apparatus for removing material from bones. It is another object of the present invention to provide a method and apparatus for properly resecting bone. It is also an object of this invention to provide a method and apparatus for properly orienting a resection of a bone. It is a further object of the present invention to provide a method and apparatus to properly orient the resection apparatus with respect to a bone. It is an additional object of the present invention to provide a method and apparatus for properly locating a bone resection. It is a further object of the present invention to provide a method and apparatus to properly locate the resection apparatus with respect to a bone. It is even another object of the resection apparatus of the present invention to provide a guide device and method of use thereof for establishing the location and orientation of the resection apparatus with respect to a bone. It is an additional object of the present invention to provide a method and apparatus for making a curvilinear bone resection. It is still a further object of the resection apparatus of the present invention to lessen the chances of fatty embolisms. It is even further object of this invention to provide a method and apparatus capable of forming or re-forming some or all of the surfaces or resected surfaces of a bone. It is another object of the present invention to provide a method and apparatus which is simple in design and precise and accurate in operation. It is also an intention of the present invention to provide a method and apparatus for determining the location of the long axis of a bone while lessening the chances of fatty embolisms. It is also an object of the present invention to provide a method and apparatus to physically remove material from a bone in a pattern. It is an additional object of the present invention to provide a method and apparatus to physically remove material from a bone in a pattern dictated by a pattern device and/or the geometry of a cutting device. It is even another object of the resection apparatus of the present invention to provide a cylindrical or semi-cylindrical cutting device and method of use thereof for removing material from a bone. It is also an object of the present invention to provide a method and apparatus for easily and accurately resecting a bone. It is also an object of the present invention to provide a method and apparatus for resecting a bone which minimizes the manual skill necessary to complete the procedure. It is even another object of the present invention to provide a method and apparatus for resecting a bone which is easy to use. It is still yet another object of the present invention to provide a method and apparatus for resecting a bone which minimizes the amount of bone removed. It is a further object of the present invention to provide a method and apparatus for resecting a bone which allows one to visually inspect the location of the cut or cuts prior to making the cut or cuts. It is yet a further object of the present invention to provide a method and apparatus for resecting a bone which physically removes material from the bone along a surface dictated by a guide device. It is still a further object of the present invention to provide a method and apparatus for resecting a bone which employs a milling bit or form cutter for removing material from the bone. It is even another object of the present invention to provide a method and apparatus for removing material from a bone such that both the cutting path and cutting profile are predominantly curvilinear. It is a primary object of the present invention to provide an apparatus to properly replace damaged bony tissues. It is also an object of this invention to provide an apparatus to properly replace damaged bony tissues in joint replacement surgery. It is also an object of the present invention to provide an implant for the attachment to a distal femur in the context of knee replacement surgery. It is an additional object of the present invention to provide a method and apparatus for making a curvilinear implant. It is another object of the present invention to provide an implant having a reduced thickness to reduce the amount of material required to make the implant. It is even another object of the present invention to provide an implant having curvilinear fixation surfaces for increasing the strength of the implant. It is another object of the present invention to provide an implant having a fixation surface that is anterior-posterior curvilinear and mediolateral curvilinear. It is another object of the present invention to provide an implant that has a fixation surface that is shaped to resemble a natural distal femur. It is also an object of the present invention to provide an implant apparatus for allowing proper patellofemoral articulation. It is a further object of the present invention to provide for minimal stress shielding of living bone through reduction of flexural rigidity. It is an additional object of the present invention to provide an implant apparatus having internal fixation surfaces which allow for minimal bony material removal. It is another object of the present invention to provide an implant apparatus with internal fixation surfaces that minimize stress risers. It is another object of the present invention to provide an implant apparatus having internal fixation surfaces for precise fixation to curvilinear body resections. It is another object of the present invention to provide an implant apparatus having internal fixation surfaces for precise apposition to curvilinear body resections. It is another object of the present invention to provide an implant apparatus having internal fixation surfaces for curvilinear interior fixation geometries closely resembling the geometry of the external or articular geometry of the implant apparatus. It is also an object of this invention to provide a method and apparatus for properly locating and orienting a prosthetic implant with respect to a bone. It is another object of the present invention to provide an implant which is simple in design and precise and accurate in operation. It is also an object of the present invention to provide an implant which minimizes the manual skill necessary to complete the procedure. It is still yet another object of the present invention to provide an implant which minimizes the amount of bone removed. It is even another object of the present invention to provide a method and apparatus for removing material from a bone such that both the cutting path and cutting profile are predominantly curvilinear. BRIEF DESCRIPTION OF THE DRAWINGS Other important objects and features of the invention will be apparent from the following detailed description of the invention taken in connection with the accompanying drawings in which: FIG. 1. is an exploded view of the resection apparatus of the present invention showing the positioning apparatus body, the angular adjustment component and the rotational alignment component. FIG. 2 is a side plan view of the guide device of the resection apparatus of FIG. 1 attached to a distal human femur. FIG. 3 is an exploded view of the pattern device of the resection apparatus of the present invention. FIG. 4 is a side plan view of the resection apparatus shown in FIG. 2 with the pattern device fixed to the distal human femur. FIG. 5 is an exploded front view of the cutting device of the resection apparatus of the present invention. FIG. 6 is a top plan view of the pattern device and the cutting device of the resection apparatus of the present invention affixed to the distal human femur. FIG. 7 is a side plan view of an intermedullary rod having a helical groove for use with the resection apparatus shown in FIG. 1. FIG. 8 is a partially exploded side plan view of an embodiment of the tibial resection apparatus of the present invention shown attached to the tibia, wherein the cutting guide clamps are of a fixed size and directly interconnect with the alignment rod. FIG. 9 is a top plan view of the tibial resection apparatus, shown in FIG. 8 prior to insertion of the milling bit into the apparatus. FIG. 10 is a partially exploded side plan view of another embodiment of the tibial resection apparatus shown in FIG. 8, wherein the cutting guide clamps interconnect with the alignment rod by means of a cutting guide clamp linkage. FIG. 11 is a side plan view of an embodiment of the cutting guide clamps shown in FIG. 8, wherein the cutting guide clamps are adjustable. FIG. 12 is a top plan view of the cutting guide clamps shown in FIG. 11. FIG. 13 is a perspective view of an embodiment of the tibial resection apparatus shown in FIG. 8, showing the proximal tibial referencing stylus attached to the cutting guide clamps. FIG. 14 is a cross-sectional view of the profile of the ends of the clamp members taken along line A-A in FIG. 12. FIG. 15 is a cross-sectional view of the profile of the ends of the cutting guides taken along line B-B in FIG. 12, the ends of the clamps mating with the ends of the cutting guides for positioning the cutting guides with respect to the clamps. FIG. 16 is a perspective view of an alternate embodiment of a U-shaped cutting guide for use in the present invention. FIG. 17 is a top plan view of another alternate embodiment of a square U-shaped cutting guide for use in the present invention. FIG. 18 is a perspective view of another alternate embodiment of a partial cutting guide for use in the present invention when the patellar tendon, patella, or quad tendon interferes with placement of the cutting guide about the tibia. FIG. 19 is a rear perspective view of an embodiment of the pattern apparatus of the present invention. FIG. 20 is a front perspective view of the pattern apparatus shown in FIG. 19. FIG. 21 is a partially exploded side plan view of the positioning apparatus shown in FIG. 19. FIG. 22 is an exploded perspective view of the cross-bar of the pattern apparatus shown in FIG. 19. FIG. 23 is a partially cut away side plan view of the pattern plate/cross-bar attachment linkage for interconnecting the pattern plate to the cross-bar as shown in FIG. 19. FIG. 24 is a perspective view of the positioning apparatus of the present invention. FIG. 25 is a top plan view of the positioning apparatus shown in FIG. 24. FIG. 26 is an exploded perspective view of the positioning apparatus shown in FIG. 24. FIG. 27 is an exploded perspective view of the protractor rod guide assembly portion of the positioning apparatus shown in FIG. 24. FIGS. 28A-28D are plan views of another embodiment of a rod guide assembly for use with the positioning apparatus shown in FIG. 24. FIG. 29 is a side plan view of an embodiment of the fixation device for affixing the pattern apparatus shown in FIG. 19 to a bone. FIG. 30 is a partial side plan view of the pattern apparatus shown in FIG. 19, showing the posterior/anterior referencing guide. FIG. 31 is a side plan view of another embodiment of the pattern apparatus shown in FIG. 19. FIG. 32 is a side plan view of another embodiment of the positioning apparatus shown in FIG. 24 for use in performing ligament balancing; FIGS. 32A and 32B are cross-sectional views along section A-A in FIG. 32. FIGS. 33A and B are front plan views of an embodiment of the cutting apparatus of the present invention for cutting a bone a in curvilinear cross-sectional plane. FIG. 34 is a perspective view of a handle for guiding a milling bit along a cutting path. FIG. 35 is a perspective view of another embodiment of the pattern apparatus shown in FIG. 19, having a milling bit engaged therewith. FIG. 36 is a side plan view of the pattern apparatus shown in FIG. 35 with the milling bit disengaged from the pattern apparatus. FIG. 37 is another side plan view of the pattern apparatus shown in FIG. 36 showing the milling bit engaged with the pattern apparatus. FIG. 38 is a perspective view of a femoral implant having a curved implant bearing surface. FIG. 39 is a side plan view of the femoral implant shown in FIG. 38. FIG. 40 is a side plan view of another embodiment of the pattern apparatus and positioning apparatus of the present invention for resecting a patella. FIG. 41 is a top plan view of the patella resection apparatus shown in FIG. 40. FIG. 42 is a front plan view of the patella resection apparatus shown in FIG. 40. FIG. 43 is a perspective view of another embodiment of the pattern apparatus of the present invention for cutting a bone. FIG. 44 is a perspective view of another embodiment of the alignment apparatus shown in FIG. 24. FIG. 45 is a partially exploded side plan view of another embodiment of the pattern apparatus of the present invention for cutting a bone. FIG. 46 is a partially exploded perspective view of the interconnection of a handle with milling bit for use in connection with pattern plate shown in FIG. 45. FIG. 47 is front plan view of another cutting apparatus for use in connection with the present invention. FIG. 48 is a side plan view of the femoral implant shown in FIG. 38, FIGS. 48A, 48B, 48C and 48D being sectional views taken along lines A-A, B-B, C-C and D-D of FIG. 48, respectively. FIG. 49 is a side plan view of the curvilinear milling bit and resection guide shown in FIG. 35. FIG. 50 is a side plan view of another embodiment of the femoral implant shown in FIG. 38. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown generally in FIGS. 1-6, the resecting apparatus of the present invention comprises a number of components, namely positioning apparatus generally indicated at 10 comprising positioning body generally indicated at 12, angular adjustment block generally indicated at 32, rotational alignment device generally indicated at 50, pattern device generally indicated at 59 and cutting means generally indicated at 90. As shown in detail in FIG. 1, the positioning apparatus, generally indicated at 10, includes a positioning body generally indicated at 12 having sides 13, top surface 14, front surface 15, back surface 19 and cross member 18. Extending from a lower end of the positioning body 12 is positioning tongue 20 having an upper surface 22. Extending into the positioning body 12 from top surface 14 to the cross member 18 and through the front and back surfaces 15 and 19, is a gap generally defined by slots 16 and partial slot walls 17. Sides 13 include apertures 24 for receiving locking screws 25. Also extending through the body 12 from the back surface 19 to the front surface 15 are apertures 27 for receiving fixation screws 26. The positioning apparatus 10 receives and holds angular adjustment block generally indicated at 32. Angular adjustment block 32 includes a front surface 34 having wings 36 sized to be received by the slots 16 in the positioning body 12 to hold the angular adjustment block 32. The angular adjustment block 32 is locked into place in the positioning body 12 by means of locking screws 25, which extend through apertures 24 in the positioning body 12 and contact the wings 36 of the angular adjustment block 32 to secure the angular adjustment block 32 to the positioning body 12. The angular adjustment block 32 establishes the angular alignment and anterior/posterior location of the positioning apparatus 10. The angular adjustment block 32 also includes back surface 38 and an aperture 40 extending from the back surface 38 through the angular adjustment block 32 to the front surface 34. The aperture 40 receives an intermedullary rod 42 therethrough. The intermedullary rod 42 comprises a shaft 43 and a handle 44. The shaft 43 extends through the angular adjustment block 32 and into the intermedullary canal which extends along the axis of the femur to aid in establishing the orientation of the resection apparatus of the present invention as hereinafter described. The rotational alignment device, generally indicated at 50, includes a shaft 51 having a groove 52 therealong and a block 53 having a back surface 54 and wings 56. The rotational alignment device 50 is interconnected with the positioning body 12 by means of the wings 56 received in slots 16 of the positioning body 12. The rotational alignment device 50 may be secured to the positioning body 12 by means of locking screws 25 which extend through apertures 24 in the positioning body 12 to contact the wings 56. The locking screws 25 may be made of various configurations depending upon their specific function. Importantly, the locking screws 25 are used to rigidly affix one component or device to another to ensure that the relative locations and orientations are maintained despite the rigors of surgery. As shown in FIG. 2, wherein the positioning body 12 is fitted with the angular adjustment block 32 and the rotational alignment device 50, the entire positioning apparatus 10 is connected to a human femur 7 by means of the shaft 43 of the intermedullary rod 42. The shaft 43 extends through the angular adjustment block 32, and thereby through the positioning body 12 into the intermedullary canal which extends along the axis of the femur 7. The intermedullary rod 42, shown in FIG. 7, has a groove 41 transversing a helical path 45 along the axis of the shaft 43. The groove 41 relieves intermedullary pressure that leads to fatty embolisms. The basic concept of the intermedullary rod 42 with the groove 41, is that as it is inserted into the femur, which contains liquid fatty tissue, the liquid fatty tissue is drawn up the groove 41 of the intermedullary rod 42 to draw the fatty liquid tissue out of the femur. Preferably, the intermedullary rod would have a hexagonal head, (not shown) to permit it to be driven by a powered device such as an electrical hand held tool. Importantly, the groove 41 does not have a cutting edge, which would risk perforation of the femoral cortex. Accordingly, the device does not cut solid material, but removes liquid material from the intermedullary canal. Therefore, the risk of fatty embolism is reduced. After positioning body 12 is properly located against the femur 7 by means of the intermedullary rod 42 and the angular adjustment block 32, fixation screws 26 may be advanced through the apertures 27 in the positioning body 12 until they make contact with the distal femoral condyles of the femur 7, and are then driven into the distal femoral condyles of the femur 7 to initially affix the positioning apparatus to the distal femur 7. It should be noted that the fixation screws 26 may also be advanced and adjusted to make up for deficiencies in the distal femoral condyles. Accordingly, the positioning body 12 is positioned such that the front surface 15 is put into contact with the distal femoral condyles by direct contact, and the tongue 20 is positioned under the femur 7 and in contact therewith. As can be seen in FIG. 2, the shaft 51 of the rotational alignment device 50 extends above the femur 7 and allows for rotation of the pattern device 59, hereinafter described, about the distal femur 7. Additionally, the rotational alignment device 50 allows for the anterior/posterior positioning of the pattern device 59 with respect to the femur 7. Importantly, the configurations of the positioning body 12, the angular adjustment block 32 and the rotational alignment device 50 are not limited to the structure set forth herein, but may be of different shapes and may interconnect in different ways. These components may even be formed as a unitary or partially unitary device. As shown in FIG. 3, the pattern device 59 includes pattern plates 60 having tops 61, and cutting paths, generally indicated at 62, extending therethrough. The cutting paths 62 outline the desired resection shape of the distal femur 7. Generally, the cutting paths 62 could include a first vertical path 64, extending to a first diagonal path 65, extending to a second diagonal path 66, extending to a second vertical path 67, extending to a third diagonal path 68 and then extending to a horizontal path 69. Alternatively, the cutting paths 62 could describe any desired resection shape for the femur 7. The pattern plates 60 also include locking screws 75 for interconnecting the pattern plates 60 with a crossbar 80. The pattern device 59 of the present invention preferably includes two pattern plates 60 held in a spaced apart relationship by crossbar 80. The crossbar 80 separates the pattern plates 60 sufficiently to permit the pattern plates 60 to extend along the sides of the distal femur 7. The crossbar 80 includes a front surface 82, back surface 84, a top surface 83, a central aperture 86 extending from the front surface 82 to the back surface 84, a lock aperture 88 extending through the top surface 83, and a lock screw 89. The central aperture 86 of the crossbar 80 receives the shaft 51 of the rotational alignment device 50. Accordingly, the pattern device 59 is interconnected with the positioning apparatus 10 so that the pattern device 59 is properly oriented with respect to the femur 7. Upon proper positioning of the crossbar 80, with respect to the shaft 51 of the rotational alignment device 50, lock screw 89 is extended through lock aperture 88 to contact the shaft 51 to lock the crossbar 80 and, accordingly, the pattern device 59, onto the shaft 51 of the rotational alignment device 50, and accordingly, to positioning apparatus 10. This completed assembly is attached to the femur 7, as shown in FIG. 4. As additionally shown in FIGS. 3 and 4, the pattern plates 60 include plate apertures 72 for receiving cannulated screws 70 which have apertures extending therethrough for receiving fixation nails 71 therethrough. Accordingly, after the pattern device 59 is interconnected with the positioning apparatus 10, and properly located and oriented with respect to the femur 7, the cannulated screws 70 are extended through the plate aperture 72 to contact the sides of the distal femur 7. Then, in order to fix the pattern plates 60 with respect to the femur 7, the fixation nails 71 are driven into the distal femur 7 to lock the pattern plate 60 into position on the distal femur 7. The cannulated screws 70 have sharp leading edges for allowing decisive purchase in the distal femur 7 before the introduction of the fixation nails 71 to complete fixation of the pattern device 59 to the distal femur 7. The pattern plates 60 by virtue of the cutting paths 62, dictate the shape of the resection of the femur 7. The cutting paths 62 are essentially channels through the pattern plates 60. The cutting paths 62 receive the cutting device and guide it as it resects the surface of the distal femur 7. The pattern plates 60 straddle the distal femur 7 mediolaterally and are suspended by the crossbar 80. Likewise, crossbar 80 maintains the proper relationship between the pattern plates 60 before and during the resection of the distal femur 7. The location of the crossbar 80 and accordingly, the pattern plates 60, may be adjusted with respect to the positioning apparatus 10 by adjusting the position of the block 53 of the rotational alignment device 50 within the slots 16 of the positioning body 12, and locking the same with locking screws 25. The cutting paths 62 in the pattern plates 60 receive and guide the cutting device shown in FIG. 5 and generally indicated at 90. The cutting device 90 performs the actual cutting of the femur 7 to resect the femur 7. The cutting device may be of any known configuration. In a preferred embodiment, the cutting device is a drill. The drill 90 is generally cylindrical in shape and may possess helical cutting teeth along its length to cut the femur 7. The drill 90 includes a hexagonal end 95 to permit the use of an electric powered drive, typically an electric drill. Further, the drill 90 includes drill bushings 92 at the ends of the drill 90 to provide a non-metallic bearing between the cutting paths 62 in the pattern plates 60 to avoid galling and to ensure smooth articulation of the drill 90 along the cutting path 62. Positioned between the drill bushings 92 and the drill 90 are retention springs 94 which are essentially coil springs retained within the drill bushings 92 to allow the drill bushings 92 to be easily attached and removed from the drill 90. These retention springs 94 are commercially available in medical grade stainless steels. The drill bushings 92 retain the retention springs 94 which hold the drill bushings 92 in position 92 on the drill 90 while allowing the drill bushings 92 to rotate freely. The drill 90 may also include circumferential grooves 91 for allowing attachment and retention of the drill bushings 92 by means of the retention springs 94. Importantly, the configuration of the drill 90 can vary in accordance with what is known in the art, as long as the cutting device can follow the cutting paths 62 in the pattern plates 60 to resect the femur 7. As shown in FIG. 6, after the pattern device 59 is attached to the distal femur 7, and positioned accordingly by means of the positioning apparatus 10, and secured to the distal femur 7 by means of cannulated screws 70 and fixation nails 71, positioning apparatus 10 may be removed from connection to the distal femur 7 leaving the pattern device 59 attached to the distal femur 7 to permit resecting of the distal femur. The drill 90 is then positioned within the cutting paths 62 between the pattern plates 60. Next the drill 90 is rotated by power means in connection with the hexagonal end 95, and is then moved along the cutting path 62 to resect the distal femur 7. It should also be noted that the cutting means could be operated by hand. Instead of two pattern plates 60, a single pattern plate could be employed if it is sufficiently sturdy to support and guide the drill. The pattern plates 60 may also comprise plates having edges in the shape of the desired distal femoral resection pattern. Thus, the cutting device may be drawn along the edges of the pattern plates to resect the distal femur. Further, any cutting device that can be employed to follow the cutting paths in the pattern plates is considered to be within the scope of this invention. The resection apparatus of the present invention, through proper use as previously described, provides extremely accurate and reproducible bone cuts. While the anterior and distal areas of the femur will almost always be able to be prepared in this manner, interference from soft tissue such as fat and ligaments may prohibit satisfactory preparation of the posterior femur. The preparation of any remaining femoral surfaces may be completed in any manner known in the art after using the instrumentation of the present invention. As shown in FIGS. 8-13, the tibial resection apparatus of the present invention includes a number of components, namely, cutting guide clamps generally indicated at 210, cutting guides generally indicated at 220, ankle clamp generally indicated at 250, alignment rod generally indicated at 260, cutting guide clamp linkage generally indicated at 270, fixation block generally indicated at 280, proximal tibial referencing stylus generally indicated at 290, and milling bit generally indicated at 255. It should be noted that the cutting guides 220 may be formed integrally with the cutting guide clamps 210 as shown in FIGS. 8 and 9, or as separate members as shown in FIGS. 11, 12 and 13. Also, the cutting guides 220 may ride the alignment 260 as shown in FIGS. 8 and 9, or they may interconnect with the alignment rod 260 by means of cutting guide clamp linkage 270, as shown in FIGS. 11, 12 and 13. As shown in FIG. 8, the ankle clamp 250 is attached at or just above the ankle and exterior to the skin. Any conventional ankle clamp may be used to firmly engage the ankle, or to engage the tibia above the ankle, to obtain a reference point for the other components of the present invention. The ankle clamp is interconnected with and locked into place on the alignment rod 260 in any way known in the art. Preferably, though not necessarily, the alignment rod 260 is vertically adjustable with respect to the ankle clamp 250. This vertical adjustment can be achieved at the ankle clamp 250, at the interconnection of the ankle clamp 250 and the alignment rod 260, or within the alignment rod 260 itself. As shown in FIG. 8, the alignment rod includes a first lower end 262 having an aperture 263 extending vertically therein for telescopically receiving a second upper end 265 of the alignment rod 260. A set screw 264 is provided for fixing the upper end 265 with respect to the lower end 262. The fixation block 280 is interconnected with an upper end of the alignment rod 260 by means of an aperture 282 in the fixation block 280 sized to receive the alignment rod 260 therethrough, or in any other manner known in the art. A set screw 284 may be provided to extend into the fixation block 280, through set screw aperture 286 in fixation block 280, to contact the alignment rod 260, to lock the fixation block 280 onto the alignment rod 260. The fixation block 280 additionally includes apertures extending vertically therethrough for receiving fixation pins 288 for affixing the fixation block 280 to the proximal tibia 208. In operation, the ankle clamp 250 is attached about the ankle, or about the tibia just above the ankle, on the exterior of the skin. The fixation block 280 is already interconnected with the alignment rod 260. It is preliminarily positioned over the proximal tibia 208, and one of the fixation pins 288 is driven into the proximal tibia 208. Thereafter, the alignment rod 260 is adjusted to establish proper varus/valgus alignment and flexion/extension angulation as is conventionally known. Upon proper alignment of the alignment rod 260, the other fixation pin 288 is driven into the proximal tibia 208 to completely fix the fixation block 280 to the proximal tibia 208 to lock in the proper alignment of the alignment rod 260. Then, the fixation block 280 may be locked into position on the alignment rod 260. After properly aligning and locking in the alignment of the alignment rod 260, the cutting guide clamps 210 and the cutting guides 220 may be employed. The cutting guide clamps 210 are interconnected with the alignment rod 260 by means of cutting guide linkage 270. Alternatively, the cutting guide clamps 210 could directly interconnect with the alignment rod 260 through apertures in the cutting guide clamps 210, as shown in FIGS. 8 and 9. As shown in FIG. 10, the cutting guide clamp linkage 270 comprises a body 271 having an alignment rod aperture 272 for receiving and riding the alignment rod 260 and a pivot locking set screw 274 which extends into the cutting guide clamp linkage 270 through set screw aperture 275 for contacting the alignment rod 260 and locking the cutting guide clamp linkage 270 with respect to the alignment rod 260. It should be pointed out that it may be desirable for the alignment rod 260 to have a flattened surface extending longitudinally along the alignment rod 260 for co-acting with set screw 274 for maintaining proper alignment between the cutting guide clamp linkage 270 and the alignment rod 260. The cutting guide clamp linkage 270 also includes a pivot shaft 276 rigidly interconnected with the body 271 of the cutting guide clamp linkage 270 by member 277 to position the pivot shaft 276 a distance away from the body 271 such that the cutting guide clamps 210 can be interconnected with the pivot shaft 276 and can be properly utilized without interfering with the body 271 of the cutting guide clamp linkage 270. After the alignment rod 260 is properly aligned and locked into position, the cutting guide clamp linkage 270 is moved into its approximate desired position at the proximal tibia 208. It should be noted that the cutting guide clamp linkage 270 of present invention is positioned on the alignment rod 260 at the beginning of the procedure, prior to aligning the alignment rod 260, and prior to interconnecting the fixation block 280 with the alignment rod 260. However, it is within the scope of the present invention to provide a cutting guide clamp linkage 270 which is attachable to the alignment rod 260 after the alignment rod 260 has been aligned and locked into position. After the cutting guide clamp linkage 270 is preliminarily approximately located, it is locked into place on the alignment rod 260. Thereafter, the cutting guide clamps 210 may be interconnected with the pivot shaft 276 by means of corresponding pivot apertures 217 in the cutting guide clamps 210. As shown in FIGS. 11 and 12, the cutting guide clamps 210 include opposing hand grips 212 for grasping and manipulating the cutting guide clamps 210. Crossbar members 214 extend from the hand grips 212 to clamp members 218. The crossbar members 214 cross over each other at cross over point 215 whereat the crossbar members 214 have mating recessed portions 216 which function to maintain the hand grips 212 in the same plane as the clamp members 218. At the cross over point 215, the crossbar members 214 can pivot with respect to each other such that movement of the hand grips 212 towards each other moves the clamp members 218 together, and likewise, movement of the hand grip members 212 away from each other serves to move the clamp members 218 apart in the same manner as scissors or pliers. At the cross over point 215, the crossbar members 214 have corresponding pivot apertures 217 for receiving the pivot shaft 276 of the cutting guide clamp linkage 270. Thus, the cutting guide clamps 210 pivot about the pivot shaft 276 of the cutting guide clamp linkage 270. It should be noted that the crossbar members 214 could be interconnected with each other by a rivet or other means known in the art, or could be entirely independent pieces which co-act as set forth above only upon being seated on pivot shaft 276. The clamp members 218 of the cutting guide clamps 210 include cutting guide adjustment screw apertures 219 at the far ends thereof for receiving A-P adjustment screws 230 for adjustably interconnecting the cutting guides 220 with the clamp members 218, for adjustable movement in the direction shown by arrow C in FIG. 11. The clamp members 218 may be adjustably interconnected with the cutting guides 220 in any way known in the art. In one embodiment, the cutting guide adjustment screw apertures 218 are threaded and the cutting guides 220 have corresponding elongated apertures 228 extending over a portion of the length thereof for receiving the A-P adjustment screws at a desired location therealong. The A-P adjustment screws include a head 231, a retaining head 232, and a threaded shaft 234. When the cutting guides 220 are positioned correctly with respect to the clamp members 218, the A-P adjustment screws 230 are tightened down to lock the cutting guides 220 onto the clamp members 218 by actuating the head 231 to turn down the threaded shaft 234 with respect to the clamp member 218. Note the retaining head 232 of the A-P adjustment screws prevent the shaft 234 from being backed off out of engagement with the clamp member 218. As shown in FIGS. 14 and 15, respectively, the clamp members 218 are shaped with opposing interior edges having chamfers 238 and the opposite exterior edges of the cutting guides 220 have mating recesses 239, both of said profiles extending along the contacting surfaces of the clamp members 218, as seen along line A-A in FIG. 12, and the cutting guides 220, as seen along line B-B in FIG. 12, to maintain a proper planar alignment therebetween. It should of course be noted that any other method known in the art may be employed to maintain the clamp members 218 and the cutting guides 220 in alignment. Additionally, the cutting guides 220 may include A-P adjustment screw recesses 237 for receiving the head 231 of the A-P adjustment screw 230. The cutting guides 220 further include tibia attachment means for attaching the cutting guides 220 to the tibia 208. Any known attachment means may be employed to attach the cutting guides 220 to the tibia 208. As shown in FIGS. 9 and 11, a preferred attachment means for attaching the cutting guides 220 to the tibia 208 are pins 236 extending through pin apertures 227 in the cutting guides 220. The pins 236 may be captured in the pin apertures 227, or they may be entirely separate. Preferably, means exist on the cutting guides 220 for preliminarily attaching the cutting guides 220 to the tibia 208 prior to pinning the cutting guides 220 thereto, so that after proper positioning of the cutting guides 220, the hand grips 212 can be actuated by squeezing the hand grips 212 together to contact the cutting guides 220 against the tibia 208 so that the cutting guides 220 are preliminarily attached to the tibia 208. Such means may include a plurality of small pins captured by the cutting guide 220, or any other suitable means. After the preliminary attachment of the cutting guides 220 to the tibia 208, final attachment may be made by attachment pins 236 or by any other means known in the art. The cutting guides 220, importantly, include cutting slots 222 which each comprise lower cutting slot guide surface 223 and upper cutting slot retaining surface 225, as well as cutting slot entrance and exit 224 at one end thereof and cutting slot end wall 226 at the other end thereof. The cutting slot 222 is of a length sufficient to extend across the proximal tibia 208, at a desired angle to the intermedullary canal, at the widest point of the proximal tibia 208, to allow the entire upper surface of the proximal tibia 208 to be cut. The cutting slot 222 is of a size sufficient to receive a cylindrical milling bit 255 such as that shown in FIG. 16 and described in U.S. Pat. No. 5,514,139, filed Sep. 2, 1994 by Goldstein, et al. The milling bit 255 comprises central cutting portion 257 having helical cutting teeth along its length for cutting bone. The milling bit 255 further comprises spindles 256 extending from the central cutting portion 257 for supporting the central cutting portion 257. The milling bit 255 is inserted into and received in the cutting slot 222 through cutting slot entrance 224, along the direction shown by arrow A in FIG. 16. Note that the cutting slot entrance 224 may be of a wider slot area or an upturned portion of the slot 222 or the milling bit 255 may merely be inserted and removed from the slot 222 at an end thereof. The spindles 256 extend through and co-act with the lower cutting guide surface 223 and the upper retaining surface 225 of the cutting slot 222 to guide the milling bit 255 along the cutting slot 222 to resect the proximal tibia 208, along the direction shown by arrow B in FIG. 16. At an end of one or both of the spindles 256 is a means for engaging the milling bit 255 with a drive means such as an electric drill, or other drive means. This engagement means may include a hexagonal head on one of the spindles, or any other suitable method of engagement known in the art. Additionally, bushings may be employed, either on the milling bit 255 or captured by the cutting slot 222, to provide a non-metallic bearing between the spindles 256 of the milling bit 255 and the cutting slot 222 to avoid galling and to ensure smooth articulation of the milling bit 255 along the cutting slots 222. Importantly, the configuration of the milling bit 255 may be varied in accordance with what is known in the art, as long as the cutting device can follow the cutting path of the cutting slot to resect the proximal tibia. Additionally, it should also be pointed out that other cutting tools may be used in accordance with the present invention, including an oscillating or reciprocating saw or other means for resecting the tibia by following the cutting slots on the cutting guides. After the cutting guide clamps 210 are preliminarily located along the alignment rod 260, the cutting guides 220 are adjusted with respect to the clamp members 218 for proper anterior-posterior positioning to extend along the proximal tibia 208 for guiding the milling bit 255. Importantly, the cutting slots 222 should extend beyond the edges of the proximal tibia 208. Once proper anterior-posterior alignment is obtained, the cutting guides 220 may be locked into place on the clamp members 218. Thereafter, a proximal tibial referencing stylus 290 may be attached to a referencing bracket 292 on the cutting guides 220. The referencing bracket 292 may be positioned in any location on the cutting guides 220, or on any other convenient component of the tibia resection system of the present invention. Alternatively, the referencing stylus 290 may be formed as part of a component of the present invention, or as a separate component which could function merely by contacting the cutting guides 220 of the present invention or any other component thereof. The referencing stylus 290, shown in FIG. 13, includes stylus body 294 which may be interconnected with the referencing bracket 292 in any manner known in the art, preferably by a quick release and connect mechanism or a threaded connection. The stylus body 294 supports a stylus arm 296, which is rotatable with respect to the stylus body 294 and configured to extend out and down from the stylus body 294 to contact the proximal tibia 208 at a tip 298 of the stylus arm 296. The stylus body 294, arm 296 and tip 298 are sized to contact the proximal tibia 208 to reference the positioning of the cutting guides 220 to cut the proximal tibia at a proper distance below the proximal tibia 208 as is known in the art. The stylus arm 296 may include more than one tip 298, such other tips extending down from the stylus body 294 in varying distances. In operation, one determines the desired location of the stylus tip 298, unlocks the cutting guide clamp linkage 270 to permit the linkage 270 to move up and down the alignment rod 260, and places the tip 298 on the lowest point of the proximal tibia 208 to reference the position of the cutting guides with respect to the proximal tibia 208 and with respect to the alignment rod 260. Thereafter, the cutting guide clamp linkage 270 is locked to the alignment rod 260 to lock the cutting guides 220 into the proper position on the alignment rod 260, and accordingly, into proper position with respect to the proximal tibia 208. Thereafter, the hand grips 212 are actuated to press the cutting guides 220 against the proximal tibia 208 to preliminarily lock them into position on the proximal tibia 208. Next, the cutting guides 220 are fixed to the proximal tibia 208 by pins 236 or any other desired fixation means. The fixation block 280 can then be removed from the proximal tibia 208, and the proximal tibia 208 may be resected. The cutting operation is similar to the cutting operation set forth in U.S. Pat. No. 5,514,139, filed Sep. 2, 1994 by Goldstein, et al. Essentially, the cutting operation comprises inserting the milling bit 255 into the cutting guide slots 222 through the slot entrance/exit 224 to position the central cutting portion 257 between the cutting guides 220, the spindles 256 extending through the cutting guide slots 222. After the milling bit 255 is positioned, the drive means may be interconnected therewith, actuated, and the milling bit 255 moved along the cutting slots 222 to resect the proximal tibia 208. It should be noted that a handle may be provided for attachment to the spindle which is not driven so that such spindle may be guided evenly through the cutting slots 222 to facilitate the cutting procedure. Alternatively, a handle can be provided which interconnects with both spindles to further facilitate control of the milling bit 255 during the cutting procedure. Additionally, the bushings that fit over the spindles 256 of milling bit 255 and ride in the cutting slots 222 may be captured in the ends of the handle and the milling bit received therethrough. Additionally, it should be pointed out that it is within the scope of the present invention to modify the cutting slots 222 such that the upper retaining surface is eliminated, and the milling bit 255 merely follows the lower cutting guide surface 223. With the cylindrical milling bit 255 herein described, this is especially viable as the milling bit 255 tends to pull down into the bone as it is cutting, thereby primarily utilizing the lower cutting guide surface 223 of the cutting guide 220. As shown in FIGS. 16-18, various other embodiments of the cutting guides are considered within the scope of the present invention. The cutting guide 320 shown in FIG. 16 is of a generally U-shaped configuration, having cutting guide slots 322, lower cutting guide surface 323, upper retaining surface 325, pin apertures 327 and alignment rod aperture 328. This cutting guide 320 is used in the same manner as the cutting guides hereinbefore described, the differences being that the cutting guide 320 interconnects directly with the alignment rod and that various size cutting guides must be provided to accommodate various sized tibias. Likewise, the cutting guide 320, shown in FIG. 17, operates in the same manner as the cutting guide devices hereinbefore described, but it does not include cutting guide clamps. The cutting guide 320 includes cutting slots 322, and it interconnects directly with alignment rod by means of aperture 328. The distance between facing members 330 can be adjusted by moving base members 332 and 334 with respect to each other to size the cutting guide 320 for the tibia to be cut. Upon proper sizing, the base members 332 and 334 may be locked with respect to each other by set screw 336 or any other means known in the art. FIG. 18 shows an embodiment of the cutting guide for use when the patellar tendon, the patella, or the quad tendon interferes with the placement of the other cutting guides of the present invention. As shown in FIG. 18, the cutting guide 350 may be directly interconnected with the alignment rod, and positioned on the tibia as hereinbefore set forth. Basically, this embodiment of the invention includes only one cutting guide. The cutting guide 350 and the cutting guide slot 322 may be wider than in the previous embodiments to help stabilize the milling bit in operation. In this embodiment, the milling bit may be first plunged across the tibia, and then moved therealong. The milling bit may be spring loaded to increase resistance as it is plunged through the cutting guide to bias the bit against being plunged too far across the tibia to cause damage to the tissue about the tibia. Additionally, a support member, not shown, could be provided to extend from the cutting guide 350, over and across the tibia to the other side thereof where it could have a slot to capture the milling bit and provide additional support thereto. The reference numerals 338, 360 and 392 correspond to the reference numerals 238, 260 and 292 respectively. As shown generally in FIGS. 19-23, the pattern apparatus of the present invention, generally indicated at 430, comprises pattern plates, generally indicated at 432, and crossbar apparatus, generally indicated at 440. Pattern Plates Pattern plates 432 include fixation apertures 434 extending therethrough for accepting fixation means, as will hereinafter be described, for affixing the pattern plates 432 to a bone. The pattern plates 432 further include a cutting path 436 for dictating the path along which a bone is to be cut. As shown in FIGS. 19-23, which are directed to an embodiment of the present invention for resecting a distal femur, the cutting path 436 in the pattern plates 432 matches the profile of a femoral component of a knee prosthesis for resecting the femur to accept the femoral component of the prosthesis. Importantly, as will hereinafter be described, the cutting path 436 could be identical in size and shape to an interior bearing surface of a femoral component of the knee prosthesis, or could vary in size and shape in accordance with alternative methods and apparatus used to perform the resection. For example, the cutting path could be larger than the desired resection, but a larger cutting tool could be used to arrive at a resection of the desired the desired size. In the embodiment of the present invention shown in FIG. 21, the cutting path 436 includes an anterior end 436A, an anterior cut portion 436B, an anterior chamfer portion 436C, a distal cut portion 436D, a posterior chamfer portion 436E, a posterior cut portion 436F, and a posterior end 436G. Alternatively, the cutting path 436 could be of any desired shape in accordance with the prosthesis systems of the various manufacturers of such prosthesis, the desires of the surgeon utilizing the apparatus and/or the application for which a bone is to be cut. Although a single pattern plate 432 may be employed in resecting a femur or other bone (and in some cases, i.e., a partial femur resection, it may be preferable to employ a single pattern plate 432), two pattern plates 432 are generally employed to co-act with each other to support a cutting means on two sides of a bone to be cut. In the case of resecting a femur, a preferred embodiment of the present invention, as shown in FIGS. 19-21, comprises two pattern plates 432 positioned on opposing sides of a femur. The pattern plates 432 are interconnected with each other, and maintained in proper alignment with respect to each other by a crossbar apparatus generally indicated at 440, to straddle a bone. The pattern plates 432 include crossbar apertures 438 for interconnecting with the crossbar apparatus 440. The pattern plates may also include crossbar slots 439 for permitting quick connect/disconnect between the pattern plates 432 and the crossbar apparatus 440. Of course, it should be noted that the pattern plates 432 could interconnect with the crossbar in any other manner known in the art, or especially with bone cutting applications other than resecting the femur, the pattern plates 432 could be used without a crossbar. Crossbar Apparatus The crossbar apparatus 440 includes a number of component parts, namely, T-bar 442 having a top 444 and a stem 446 interconnected with and extending from the top 444 in the same plane. The T-bar 442, shown in the figures, comprises a flat metal member having a uniform rectangular cross-section through both the top 444 and the stem 446. Three threaded lock apertures 448 are formed through the T-bar 442, one at each end of the top 444 and at the far end of the stem 446. Lock screws 450, having gripable heads 452 and shafts 454 with threaded waists 456, threadably engage the threaded lock apertures 448 in the T-bar 442. The lock screws 450 further include pin holes 458 extending radially through the shafts 454 at the terminal ends thereof for receiving pins 459 for capturing the lock screws 450 on the T-bar 442. The crossbar apparatus 440 further includes linkages 460 having a first end for interconnection with the T-bar 442 and a second end for supporting and engaging pattern plates 432. The first ends of the linkage 460 include a lower flat surface 462 for contacting the T-bar 442, overhanging shoulders 464 for contacting the sides of the T-bar 442, and an upper flat surface 466 for contact with the lock screws 450 for locking the linkages 460 onto the T-bar 442. As shown in detail in FIG. 23, the second ends of the linkage 460 include cylindrical supports 468 for supporting the pattern plates 432 thereon. The cylindrical supports 468 include axial extending apertures 469 for receiving capture pins 470 therethrough, the capture pins 470 including flanged ends 472 and threaded ends 474. The capture pins 470 serve to capture pattern lock nuts 476 on the linkages 460, the capture pins 470 extending through the axial apertures 469, the flanged ends 472 retaining the capture pins 470 therein, the threaded ends 474 extending out of the cylindrical supports 469 and into the threaded interior 477 of the pattern lock nuts 476. The cylindrical supports 468 receive the crossbar apertures 438 of the pattern plates 432 and the pattern lock nuts 476 are threaded down onto the capture pins 470 to secure the pattern plates 432 to the crossbar apparatus 440. Of course, other embodiments of the crossbar apparatus sufficient for supporting the pattern plates of the present invention are considered within the scope of the present invention. Positioning Apparatus As shown in FIGS. 24-28, the positioning apparatus of the present invention is generally indicated at 510. The positioning apparatus generally comprises positioning body 520 and alignment apparatus 580. The positioning body 520 comprises a frame 522 having sides 524, bottom 526 and top 528 arranged to form a frame having a rectangular aperture defined therewithin. The top 528 further includes a head 530 formed thereon having a linkage aperture 532 extending therethrough at an upper end thereof, and having a lock aperture 534 extending from the upper edge of the head to the linkage aperture 532. A lock screw 536 having a threaded shaft 538 extends into and is threadably engaged with the lock aperture 534 for locking the head 530 to a linkage, namely crossbar linkage 540. Crossbar linkage 540 includes a first end having an upper flat surface 542 for interconnecting with the crossbar in a manner similar to the pattern plate linkages for attaching the pattern plates to the crossbar as hereinbefore described. The crossbar linkage 540 further includes a shaft 544 which is received by the linkage aperture 532 in the head 530 to interconnect the positioning body 520 with the crossbar linkage 540 and hence with the crossbar apparatus 440 and the pattern apparatus 430. The positioning body can then be locked onto the crossbar linkage 540 by means of lock screw 536. The end of shaft 544 of the crossbar linkage 540 includes projections 546 extending axially from the shaft 544. When the shaft 544 is positioned in the linkage aperture 532, the projections 546 extend beyond the frame 522 and are received in slots 556 in alignment indicator 550 for keying the orientation of the alignment indicator 550 with the alignment of the crossbar linkage 540, and hence with the alignment of the crossbar apparatus 440 and the pattern apparatus 430. The alignment indicator 550 includes an alignment arrow 552 for indicating alignment on a scale that may be set forth on the positioning body 520. An indicator pin 558 having a shaft 559 may be employed to pin the alignment indicator 550 to the crossbar linkage 540. Attachable to the bottom 526 of the positioning body 520 is skid 560. The skid 560 includes skid apertures 562, one of which may include an aperture flat 564 for ensuring proper alignment and positioning of the skid 560 with respect to the positioning body 520. The skid 560 is attached to the bottom 526 of the positioning body 520 by means of skid bolts 566 having threaded shafts 568 which co-act with threaded apertures in the bottom 526 of the positioning body 520. Of course, the skids could be formed integrally as part of the positioning body. The sides 524 of the positioning body 520 include slots 570 extending in a facing relationship along the sides 524. The slots extend from exterior surfaces of the sides to interior surfaces thereof, i.e., to the interior rectangular aperture formed within the positioning body 520. Alignment Apparatus The alignment apparatus 580 interconnects with the positioning body 520 by means of alignment guide body 582 which is a U-shaped member having sides 584 and a bottom 586. The alignment guide body 582 is sized to fit within the rectangular aperture formed within the positioning body 520. The alignment guide body 582 is retained within the positioning body by means of guide studs 572 that extend through the sides 524 of the positioning body 520 within the slots 570 and into guide apertures 588 at one side of the alignment guide body 582. At the other side of the alignment guide body 582 a lock stud 584 extends through the slot 570 in the side 524 of the positioning body 520 and into a threaded lock aperture 589 in the alignment guide body 582. The guide studs 572 and the lock stud 574 co-act to maintain the alignment guide body 582 within the positioning body 520, and the lock stud 574 can be threaded down to lock the vertical position of the alignment guide body 582 with respect to the positioning body 520. At upper ends 590 of the sides 584 of the alignment guide body 582 are plate apertures 591. The alignment plate 592 includes bolt apertures 595 aligned with the plate apertures 591 of the alignment guide body 582, and plate bolts 594 extend through the bolt apertures 595 in the alignment plate 592 and into the plate apertures 591 to secure the alignment plate 592 to the alignment guide body 582. The alignment plate 592 further includes rod guide aperture 597 which receives rod guide bolt 596 therethrough to interconnect the alignment plate 592 with the IM rod guide 610 as will hereinafter be described. Additionally, the alignment plate 592 includes lock slot 606 extending through the alignment plate 592 along an arc for purposes hereinafter described. The IM rod guide 610 includes IM rod aperture 612 for receiving an IM rod therethrough. The IM rod guide 610 is interconnected at a forward end with the alignment plate 592 by means of plate attachment aperture 614 on the rod guide 610 which receives rod guide bolt 596 therein, after such bolt 596 passes through the alignment plate 592 to secure the rod guide 610 in a pivoting relationship with respect the alignment plate 592 at forward ends of the rod guide 610 and the alignment plate 592. The IM rod guide 610 is additionally interconnected with the alignment plate 592 by rod guide lock bolt 600 which includes a threaded shaft 210 and pin aperture 602. The rod guide lock bolt 600 extends through the slot 606 in the alignment plate 592 and through threaded lock bolt aperture 616 in the rod guide 610 where it is captured by means of capture pin 618 extending through the pin aperture 602. The IM rod guide further includes rod guide handle 620 which is configured to be easily manipulated. The alignment plate 592 further includes a printed angular rotation scale which indicates the degree of angular rotation between the rod guide 620 and the alignment apparatus, and hence, the angular rotation between the IM rod and the positioning body 520. After such alignment is determined, it can be locked into place by tightening down rod guide lock bolt 600. Thereafter, with such angular rotation fixed, the pattern apparatus 430 can be positioned with respect to the bone to cut, and the positioning apparatus 510 can be removed from interconnection with the IM rod and the pattern apparatus 430, the IM rod removed from the bone, and bone cutting can be initiated. In another embodiment, as shown in FIGS. 28A, 28B, 28C and 28D, IM rod guide block 630 is used instead of the alignment plate 592 and the alignment guide body 582. The IM rod guide block 630 includes a rear surface 632, a front surface 634, a top surface 636 and sides 638. The sides 638 include retaining flanges 640 at the rear and front surfaces for retaining the IM rod guide block 630 within the rectangular aperture formed by the positioning body 520. The IM rod guide block 630 further includes IM rod aperture 642 extending through the block 630 from the rear surface 632 to the front surface 634 for accepting the IM rod therethrough. The rod aperture 642 extends through the guide block 630 at an angle A with respect to axis of the guide block for accommodating the varus/valgus orientation of the femur. The guide block 630 is part of a set of blocks having rod apertures of various angles extending therethrough, i.e., 5, 7, 9, 11, 13 degrees, for use with femurs having varying angles of orientation. The guide block 630 also includes lock aperture 646 for locking the proper vertical position of the guide block 630 with respect to the positioning body 620. The guide block 630 may additionally include two apertures 644 for accepting an anterior referencing arm for use in determining the anterior/posterior size of the femur. It should be noted that other alignment means for aligning the positioning apparatus with respect to a bone to be cut are considered within the scope of the present invention. Fixation Means Various fixation means, including those known in the art, can be used to fix the pattern plate or plates to the femur or other bone to be cut. FIG. 29 shows a preferred fixation means, generally indicated at 660. The fixation means 660 includes a spike plate 664 carrying on one side thereof a spike or spikes 662 for contacting, and even extending into, bone 661. At the other side of the spike plate 664 is spike plate socket 666 for receiving plate driving ball 668 in a keyed relationship therewith. The driving ball 668 is interconnected to an end of driving sleeve 670 and which has a threaded aperture extending therein from the opposite end thereof. A driving screw 672 having a threaded shaft 674 co-acts with the internally threaded driving sleeve 670 such that the rotation of the driving screw 672 either propels or retracts the driving sleeve 670, as well as the spike or spikes 662, with respect to the driving screw 672. The driving screw 672 further includes a captured head 678 and capture flange 676. The captured head 678 is received within a fixation aperture 434 in the pattern plate 432, the capture flange 676 preventing the captured head 678 from passing through the fixation aperture 434. A driving cap 680 is interconnected with the captured head 678 at the outside of the pattern plate 432. The driving cap 680 includes a shaft 682 received by the captured head 678, a flanged head 684 for contacting against the outside of the pattern plate 432, and a driver recess 686 of any desirable configuration for receiving driving means such as a flat, phillips or hex head driving means for driving the driving cap 680 to drive the driving screw 672 to move the spike or spikes 662 towards or away from a bone. Importantly, this type of fixation means allows for fixation of the pattern plates 432 to even osteoporotic bones. Additionally, this fixation means is self-adjusting to fit changing contours of bones. Further, because of its relatively low profile, this fixation means does not interfere with soft tissue about a bone to be cut. Other types of fixation means include cannulated screws, pins, spring loaded screws, captured screws, spiked screws and/or combinations thereof, all of which are considered within the scope of the present invention and could be used in connection with the present invention. Anterior/Posterior Referencing The apparatus of the present invention further includes built-in anterior/posterior referencing means as shown in FIG. 30 for use in connection with preparation of the distal femur in total knee replacement. As is known in the art, anterior/posterior referencing refers to proper positioning of the distal femur cuts with respect to the anterior and/or posterior sides of the femur or other bone to be cut. The anterior/posterior difference between femoral implant sizes may vary by as much as 3 to 5 millimeters between sizes. Of course, many femurs are between sizes. Disregarding proper positioning of the cutting guide and the associated femur cuts could lead to flexion contracture (where the bone is slightly below size and the implant adds too much material to posterior side of femur which results in the inability to move the knee into flexion because the extra posterior material contacts the tibial implant components) and/or anterior notching of the femur (where the bone is slightly above size and the anterior runout point of the anterior cut is recessed in the anterior side of the bone in a sharp notch, thus seriously weakening the structural integrity of the distal femur, especially under cyclic fatigue or impact loading conditions). Anterior referencing systems have a major advantage over posterior referencing systems in that they theoretically never notch the anterior cortex of the femur. The drawback of anterior referencing is that a slightly larger bone results in collateral ligament laxity in flexion and a slightly smaller bone will result in collateral ligament tightening in flexion (flexion contracture). Posterior referencing systems have a major advantage over anterior referencing systems in that they theoretically never develop flexion contracture. The drawback is that a slightly large femur is prone to anterior notching, which can increase the likelihood of distal femoral fractures under either impact loading or cyclic fatigue loading. Another approach to anterior/posterior referencing is a hybrid design that allows for both anterior and posterior referencing. The positioning apparatus 510 references the posterior femoral condyles (posterior referencing), while the pattern plates 432 allow for precise referencing of the anterior femoral cortex. The anterior referencing device can be as simple as that shown in FIG. 30, wherein a referencing pin 694 is placed through the anterior-most cutting paths 436 of the pattern plates 432 to contact the anterior femoral cortex 661. The pattern plates 432 include markings S (smaller size) and L (larger size). When the pin 694 falls between the S and L marks, the pattern plates 432 are the proper size and are properly positioned for that femur. If the pin 694 falls outside the range marked by S and L towards the S side, a smaller size pattern plate should be used, and conversely, if the pin 694 falls outside the range on the L side, a larger size pattern plate should be used. Alternatively, the pattern plate 432 could be adjusted vertically via means not shown to compensate for between-size bones. In another embodiment, the pattern plate could include a plunger assembly at the anterior end of the cutting path. The plunger could be movable vertically to contact the femur and indicate size of the femur with respect to the pattern plate in use. As such, the plunger could be incrementally marked from +4 to −4 millimeters with 0 being the proper size for the pattern plates in use. Again, the pattern plates could be sized up or down if the femur is off of the scale, or the pattern plates could be moved up or down to compensate for between size bones depending upon surgeon preference. If, for example, a bone registers a +2, anterior notching of the femur would occur. To avoid this, the pattern plates could be moved anteriorally 1 millimeter to +1. In this manner, anterior notching would be minimized and the posterior femoral condyles would only lack 1 millimeter of material, which should not be detrimental as some ligamentous laxity in flexion is acceptable because the collateral ligaments are normally slightly looser in flexion than they are in extension. It should be noted that the radii or curve in the anterior-most area of the cutting path will assure that anterior notching is easily avoidable. Pattern Plate with Tracking Means Another embodiment of the pattern plates of the present invention is shown in FIG. 31. In this embodiment, the pattern plates, generally indicated at 710, basically comprise only the lower edge, or bearing surface 716 of the cutting path 436 of pattern plates 432 shown in FIGS. 19-21. Accordingly, the pattern plate 710 includes fixation apertures 712 and crossbar aperture 714. The milling apparatus bears against the bearing surface and follows the same therealong to resect the bone in accordance with the shape of the bearing surface 716. Of course, the bearing surface could be smaller or larger than the desired cut location depending on the size of the milling apparatus. The pattern plate 710 could further include a groove or guide means 718 extending in the pattern plate alongside the bearing surface and the milling apparatus could include an arm or other retaining linkage 717 extending from the handle or bushing of the milling apparatus and into the groove 718 for engagement with the groove 718 for guiding or retaining the milling apparatus along the bearing surface 716 of the pattern plate 710. Alternatively, it should be noted that the bearing surface could also comprise just the upper surface of the cutting path 436 of the pattern plates 432, as shown in FIGS. 19-21. Ligament Balancing As shown in FIG. 32, an alternative embodiment of the alignment guide body 730 can be used for performing ligament balancing. The alignment guide body 730 of this embodiment can include a skid 732 formed as a part of the guide body 730, or attachable thereto. The skid 732 is of a relatively thick cross-section, approaching or equal to the cross-section of the guide body 730. The guide body 730 is attached to the femur 661 and the femur may be moved from extension to flexion and back, while the ligament tension of the collateral ligaments is reviewed. Ligamentous release can be performed to balance the ligaments. Further, shims 736, in either a rectangular cross-section (FIG. 32A) or an angled cross-section (FIG. 32B), can be used in connection with the alignment guide body 830 and skid 732. These shims could be positioned between the underside of the skid 732 and the resected tibia. Milling Means In a preferred embodiment of the invention, a cylindrical milling bit is used for following the cutting path described in the pattern plates for resecting a bone. Importantly, it is within the scope of the present invention to use a flat reciprocating bit, much like a hacksaw, for following the cutting paths described in the pattern plates for resecting a bone. Further, it may be desirable to make all or some of the cuts using a cylindrical milling bit or a flat reciprocating bit having a smooth center section without cutting means. An advantage of a cutting tool without cutting means along a center portion thereof is the protection of posterior cruciate ligament during resection of the femur. Accordingly, one cutting tool could be used to make the anterior cut, the anterior chamfer, the distal cut and the posterior chamfer, while another cutting tool, with a smooth center portion, could be used to make the posterior cut to avoid any chance of jeopardizing the posterior cruciate ligament. Additionally, the milling bits herein described can be used with or without a guide handle as will hereinafter be described. Further, it should be pointed out that it is within the scope of the present invention to fabricate the milling bit or other cutting tool from metal as heretofore known, or to alternatively fabricate the milling bit or other cutting tool from a ceramic material. An advantage of a ceramic milling bit or cutting tool is that such resists wear and, accordingly would be a non-disposable component of the present invention which would help to reduce the cost of the system of the present invention. Three Dimensional Shaping Initially, it should be noted that the term cutting profile the profile geometry of a mediolateral section taken normal to the cutting path through the bony surfaces created by cutting the bone. As shown in FIG. 33, in an alternate embodiment of the present invention, a milling apparatus having a three-dimensional profile, or a form cutter, can be used to shape a bone in three-dimensions. The curved profile milling bit 750, like the milling bits used in the previous embodiments of the present invention, includes cutting teeth 752 along the length thereof and spindles 754 at the ends thereof. This milling bit 730 can follow a pattern described by pattern plates and can be guided with a handle as will be hereinafter described. Importantly, by using a milling bit having a curved profile, one can cut a femur to resemble the natural shape of the femur, i.e., the resected femur would include condylar bulges and a central notch. This would reduce the amount of bony material that must be removed from the femur while maintaining the structural integrity of the femur. Of course, any prosthetic implant used for attachment to a femur resected by the curved profile milling bit would necessarily have an appropriately contoured inner fixation surface for mating with contoured surface of the femur. Additionally, it should be noted that the curved profile milling bit could have one or more curvilinear bulges along the length thereof, as shown in FIG. 33, or alternatively, could have one or more bulges discretely formed along the length thereof as shown in FIG. 35. Guide Handle As shown in FIG. 34, a guide handle, generally indicated at 698 may be used to guide the milling bit along the cutting path of the pattern plate. The guide handle 698 comprises a grip portion 700 which is grasped by the user for manipulating the guide handle 698 and accordingly, the milling bit. The grip portion 700 is interconnected with a crossbar member 702 which includes a extension member 703 telescopically interconnected therewith. The crossbar member 702 and the extension member 703 may be positioned perpendicular with respect to grip portion 700. The extension member 703 is telescopically movable in and out of crossbar member 702. Means may be provided for locking the relative position of the extension with respect to the crossbar. Also, it should be noted that the grip portion may rigidly or pivotally be interconnected with the crossbar as desired. Extending from outer ends of the crossbar 702 and the extension member 703 are sidebars 704 in facing and parallel relationship. The sidebars 704 have two ends, the first of which are interconnected with the crossbar and the extension member, and the second of which are configured to receive and capture spindles or bushings of a milling bit in spindle bushings 706. The spindle bushings are positioned in a facing relation and could include captured bushings. The captured bushings receive the spindles of a milling bit. The captured bushings are sized to be received by the cutting path in the pattern plates and co-act therewith to guide a milling bit therealong. Accordingly, after the pattern plate or plates are attached to a bone, the milling bit is placed into the cutting path. Next a milling handle 698 is positioned such the spindle bushings are aligned with the spindles of the milling bit. Next, the extension is actuated to retract into the crossbar to move the spindle bushings onto the spindles of the milling bit where they are captured. Next, the spindle bushings are positioned within the cutting path of a pattern plate or plates. If necessary, the extension and crossbar can be locked down to lock the entire apparatus. Next, the milling bit is actuated and the grip portion of the handle is grasped and manipulated to move the milling bit along the cutting path to cut a bone. Distally Positioned Pattern Plate As shown in FIGS. 35-37, in an alternate embodiment of the present invention for resecting a femur, the plates could take the form of a rail assembly, generally indicated at 760, positioned distally of the distal femur 661. The plates could be affixed to the femur by fixation arms 762, attached at one or more points to the rail assembly 760, and including fixation apertures 764 for receiving fixation screws or other fixation means for attaching the fixation arms 762, and hence the rail assembly 760, to a distal femur 661. The rail assembly 760 includes one or more guide rails 766 which match the shape of the desired resection, though the rails may be larger or smaller depending on the dimensions of the milling apparatus used and the positioning of the assembly 760 with respect to the femur. In the case that the assembly 760 includes two guide rails 766, as shown, an end rail 768 may be used to interconnect such guide rails 766. The end rail 768 could be replaced by a connection means similar to the crossbar apparatus 440, hereinbefore described. The rail assembly may be positioned on the distal femur in accordance with the teachings contained herein, or in any other manner known in the art. After alignment, according to any means disclosed herein or known or developed, and after fixation of the assembly to a femur, a milling bit 770 may be used to follow the guide rails 766 to resect the femur 661, the guide spindles 772, or bushings (not shown), of the milling bit 770, contacting and riding the guide rails 766. Importantly, the rail assembly 760 is attached to a femur and used in much the same way as the pattern plates previously described with the exception that the rail assembly can be positioned substantially distal of the femur, thereby potentially requiring less exposure and possibly resulting in less interference for placement thereof. The rail assembly 760 could further include an upper retaining rail for forming a slot or cutting path for capturing the milling bit therein. Additionally, it should be noted that any milling bit described herein could be used with rail assembly 760 including a curved profile milling bit. Curvilinear Implants As shown in FIGS. 38 and 39, an implant 780 may have curvilinear interior surfaces 782, as well as a more conventional curvilinear exterior surface. The particular example cited herein is a femoral implant used in total knee arthroplasty but the principles described herein may be applied to any application where foreign or indigenous material is affixed to an anatomic feature. The curvilinear bone surfaces necessary for proper fixation of such an implant may be generated through the use of the curvilinear milling or form cutter and the curvilinear cutting path means discussed herein. While it is possible to use multiple form cutters with differing geometries and, therefore, an implant with an internal geometry that varies along the cutting path from the anterior to the posterior of a femur, for the sake of intraoperative time savings a single form cutter is preferable. The mediolateral cross-sectional internal geometry of such an implant, and therefore the necessary resected bony surfaces of the femur, are consistent about the cutting path in a single form cutter system. It should be noted that the implant may possess a notch between members 784 (posterior femoral implant condyles) in the areas approximately in between the distal and posterior femoral condylar areas to accommodate the posterior cruciate ligament and other factors. Because of the notch between the posterior femoral condyles it may not be necessary for the form cutter to cut any material in the notch. It may be desirable to provide outer flat surfaces 785 with an adjoining curvilinear surface 782 positioned therebetween. Other combinations of flat or curvilinear surfaces are also within the scope of the present invention. Additionally, it may be advantageous to utilize a secondary form cutter as shown in FIG. 47 for use in creating a slot or slots in or near the distal area of the femur after it has been resected. Such a secondary cutter 790 would include engagement means 792 for engagement with driving means, and a shaft 794 carrying cutters 796 for cutting slots into the femur through one or more of the resected surfaces thereof. Through the inclusion of an additional or adjunct cutting path in the pattern means, it would be advantageous to utilize the form cutter to create the aforementioned slots to accommodate the fixation fins which may be molded as an integral part of the interior surface of the implant. These fins would provide mediolateral fixation stability in addition to that provided by the trochlear groove geometry of the implant. Further, the fins also provide for additional surface area for bony contact and ingrowth to increase implant fixation both in cemented and cementless total knee arthroplasty. There are numerous advantages to the femoral component herein described. Foremost, it will allow for the thinnest implant cross-section possible (perhaps 3 mm to 6 mm in thickness) and therefore necessitate the removal of the least amount of viable osseous tissue. This is especially critical in situations where the probability of revision surgery is high and the amount of viable bone available for revision implant fixation and apposition is a significant factor in the viability of the revision procedure. Since the form cutter configuration allows for similar amounts of tissue to be removed from the trochlear groove, the bony prominences surrounding the trochlear groove, the femoral condyles, and the other articular surfaces of the femur, the external geometry of the femoral implant can be optimized for patellofemoral articulation as well as tibiofemoral articulation. In essence, the kinematics of the artificial joint could be made to be as close as possible to that of a healthy, natural knee joint. In addition, the curvilinear geometry of the implant dramatically decreases the stress risers inherent in conventional rectilinear femoral implants and allows for a thinner cross-sectional geometry while potentially increasing the resistance of the implant to mechanical failure under fatigue or impact loading. Conversely, the curvilinear geometry of the implant may also allow for an advantageous reduction in the flexural rigidity of the implant which may result in avoidance of the “stress-shielding” inherent in rigid implant designs. Stress shielding being a phenomenon that may occur when living bony tissue is prevented from experiencing the stresses necessary to stimulate its growth by the presence of a stiff implant. This phenomenon is analogous to the atrophy of muscle tissue when the muscle is not used, i.e., when a cast is placed on a person's arm the muscles in that arm gradually weaken for lack of use. Additionally, the curvilinear implant design may allow for the use of a ceramic material in its construction. Since ceramics are generally relatively weak in tension, existing ceramic implant designs contain very thick cross-sections which require a great deal of bony material removal to allow for proper implantation. Utilization of ceramics in the curvilinear implant will not only allow for the superior surface properties of ceramic, but also avoid the excessively thick cross-sections currently required for the use of the material. This could result in a less expensive femoral implant because of the reduced amount of material needed for the implant, as well as an improved, more natural, and even stronger knee replacement. It may be desirable to vary the cross-section of the implant 780 to assist in seating the implant and to increase the strength and fit of the implant. The implants of the present invention having curvilinear implant surfaces could be fabricated of metal, plastic, or ceramic or any other material. Further, the thickness of the implants and the material required to fabricate the implant could be reduced as the implants are adapted to increasingly curvilinear surfaces. Also, it should be pointed out the such implants with curvilinear implant surfaces require less bone to be removed to obtain a fit between the implant and the bone. Finally, it should be noted that curvilinear milling bits hereinbefore described would work well for preparing a bone to receive an implant with curvilinear interior implant surface. Patella Shaping The apparatus for preparing a patella, as shown in FIGS. 40-42, comprises a plier-like patella resection apparatus generally indicated at 800. The patella resection apparatus 800 includes grip handles 802 for manipulating the apparatus, cross-over members 804 pivotally interconnected with each other by pin 806, and patella clamp members 808 extending from the cross-over members in parallel and facing relation. The patella clamp members 808 have beveled edges 810 for contacting and supporting a patella along the outer edges thereof. Guide member structures 812 are mounted on each of the patella clamp members 808 to form a retainer for a cutting means to follow a cutting path defined by the upper surface of the clamp members. Bushings 814 are captured within the retainer and the cutting path for receiving a cutting means 816 and guiding the cutting means 816 along the cutting path. In preparing the patella, the pattern device may be an integral part of the positioning apparatus which is oriented and located by referencing the geometry of the patella itself as well as the structures of the patellofemoral mechanism to determine the location and orientation of a predominantly planar resection. The cutting device may then be employed to perform the resection of the patella by traversing the path dictated by the pattern device, thus dictating the final location and orientation of the patella prosthesis. Bone Substitution and Shaping Referring now to FIG. 43, another embodiment of the pattern apparatus of the present invention for cutting bone is shown. This embodiment of the invention includes pattern plates 832 having cutting paths 836 described therein. The pattern plates 832 may be positioned on a bone 828 having a tumor or other pathology 829 associated therewith. The pattern plates 832 may be interconnected by crossbars 838 with opposing pattern plates (not shown) positioned on the opposite side of the bone 828. Further, each set of pattern plates 832 could be interconnected by means of positioning rod 839 extending between the crossbars 838 to maintain the relative location and orientation between the sets of pattern plates 832. The pattern plates can be positioned along the bone in accordance with what is known in the art, disclosed herein or hereafter developed. After the pattern plates are properly positioned, they can be affixed to the bone 828 with fixation means extending through fixation apertures 834. After the pattern plates are properly located and affixed to the bone, cutting can commence by traversing a cutting means along the cutting paths 836 of the pattern plates 832. By this step, the tumor or other pathology 829 can be cut from the bone 828 and a bone graft or other surgical procedure can be implemented to repair and/or replace the bone that has been cut. The benefits of cutting a bone with the pattern plates of the present invention include providing smooth and even cuts to the bone to facilitate fixation of bone grafts or other means for repairing and/or replacing bone. Further, the same pattern plates can be used to cut another identical sized and shaped bone for grafting to the first bone to replace the cut away bone. Alternate Positioning and Alignment Guide An alternate positioning and alignment guide is generally indicated at 840 in FIG. 44. The positioning body 840 comprises a crossbar linkage 842 and an alignment indicator 844 at an upper end thereof for interconnecting with a crossbar to align pattern plates interconnected with such crossbar. The positioning body 840 also includes an alignment block 846 for interconnecting with an intramedullary rod in much the same manner as the IM rod guide block shown in FIG. 28. The alignment block 846 is vertically movable along the positioning body 840 and can be locked into a desired position by means of lock screw 860 which bears against a flange 848 of the alignment block 846. The positioning body 840 further includes skids 850 for contacting the posterior surface of the distal femoral condyles for referencing same. Unicondylar and/or Single Pattern Plate Support As shown in FIGS. 45 and 46, one pattern plate of the present invention can be used by itself to guide a cutting means along a cutting path to cut a bone. Such an application is particularly useful for unicondylar resecting of a femur. Use of a single pattern plate 862 is facilitated by bushing 868 having an outer flange 870 with a bearing surface 872 and an internal bore 874 sized to receive a spindle 865 of a cutting tool therein. The bushing 868 is sized to fit into the cutting path 864 of the pattern plate 862, the bearing surface 872 of the flange 870 contacting the side of the pattern plate 862. Washer 876 includes a central bore 878 sized to receive the far end of the bushing 868 extending past the pattern plate 862, the washer bearing against the side of the pattern plate 862 opposite the side that the bearing surface 872 of the flange 870 of the bushing 868 bears against. Thus, the washer and the bushing co-act to form a stable link with a pattern plate. As shown in FIG. 46, this link can be fortified by means of bearing arms 880 interconnected with the bushing and the washer, or formed integrally as part thereof, which by pressure means are forced together to retain the bushing within the cutting path of the pattern plate. After the bushing is captured within the cutting path, the spindle of the cutting means can be inserted through the bushing and interconnected with means 866 for driving the cutting means. Alternatively, it should be pointed out that when using a single pattern plate to cut a bone, it may be desirable to support the cutting means at the pattern plate and also at the other end thereof. One could effect such desired support at the other end of the cutting means by a brace or other linkage interconnecting the other end of the cutting means with a secondary support or anchor means positioned on the opposite side of the bone or at another location. Revisions Conventional revisions require removal of the old implant and the referencing of uncertain landmarks. Revisions, by means of the present invention, allow for reference of the implant while it is still on the bone. One can obtain varus/valgus referencing, distal resection depth, posterior resection depth and rotational alignment by referencing the geometry of the implant with the alignment guide. An extramedullary alignment rod can be used to facilitate flexion/extension alignment. The fixation screws can then be advanced to touch the bone and mark their location by passing standard drill bits or pins through the cannulations in the fixation screws and into the bone. Then, the pattern and guide device are removed, the old implant removed, and the pattern device repositioned by means of the marked location of the fixation screws and then fixed into place. Accordingly, the cuts for the new implant, and thus the new implant itself, are located and orientated based off of the old implant. This results in increased precision and awareness of the final implant location and orientation as well as potential intraoperative time savings. The particular example of the present invention discussed herein relates to a prosthetic implant for attachment to a femur in the context of total knee arthroplasty, i.e., a femoral implant. However, it should be pointed out that the principles described herein may be applied to any other applications where foreign or indigenous material is affixed to any other anatomic feature. As shown generally in FIGS. 38 and 48, the implant apparatus of the present invention, generally indicated at 910, comprises curvilinear interior fixation surface 920 as well as curvilinear exterior bearing surface 940. Importantly, the implant of the present invention includes curvilinear surfaces extending from an anterior to a posterior area of the femur and/or implant, as is conventionally known, as well as curvilinear surfaces extending from a medial to a lateral area of the femur and/or implant to approximate the shape of natural femur. In other words, the fixation path (i.e., corresponding to the cutting path along which the milling bit rides to resect the femur; indicated by arrow A in FIG. 38) as well as the fixation profile (as one proceeds along the cutting profile orthogonally to the cutting path; indicated by arrow B in FIG. 38) are both predominantly curvilinear. As such, the cutting profile (arrow B) of the interior fixation surface 920 could include a curved or flat area 922 and another curved or flat area 924 therebetween. Preferably, the outer areas 922 are flat or relatively flat and the inner area 924 is curved to approximate the shape of a natural distal femur 912. It should be pointed out that the outer areas 922 could be curved, and the inner area 924 could also be curved, but embodying differing radii of curvature. Additionally, it should be pointed out that the geometry of the internal fixation surface 920 of the implant 910 could be varied as desired. As such, any combination of flat surfaces and curvilinear surfaces could be used. As shown in FIG. 48, and in more detail in FIGS. 48A, 48B, 48C and 48D, the cross-sectional thickness and mediolateral width of the implant of the present invention could vary along the implant 910. This variance results from merging a cutting tool to cut a bone, i.e., the implant 910 closely resembles in size and shape the material removed from the bone. Accordingly, the cut starts as a point 925 and grows in depth and width. The curvilinear bone surfaces necessary for proper fixation of such an implant 910 may be generated through the use of the curvilinear milling bit or form cutter and the curvilinear cutting path means discussed in the previous related applications set forth herein, the entire disclosures of which are expressly incorporated herein by reference. Basically, the milling bit has a profile resulting in form cutter configuration which is concentric about its longitudinal axis to effect a curvilinear cutting profile for receiving the implant of the present invention. One embodiment of such a form cutter is shown in FIGS. 35 and 49. While it is possible to use multiple form cutters with differing geometries and therefore an implant 910 with an internal geometry that varies along the cutting path from the anterior to the posterior of a femur, for the sake of intraoperative time savings, a single anatomically optimal form cutter is preferable. The form cutter shown in FIGS. 35 and 49 comprises a cutting guide 950 having cutting paths 952 interconnected by member 954. A milling bit 960 having cylindrical milling areas 962 at the ends, and a curved milling area 964 at the center could be used. Of course, the milling areas carry cutting teeth. Spindles 961 interconnected at each end of the milling bit 960 could engage and ride the cutting path 952 of the cutting guide 950. The milling bit 960 is then guided along the cutting path 952 by means of a handle. Importantly, the shape of the milling bit 960 could be varied as desired to create a resection having a desired cutting path as well as a desired cutting profile. The mediolateral cross-sectional internal geometry of such an implant 910, and therefore the necessary resected bony surfaces of the femur, are consistent about the cutting path in a single form cutter system. It should be noted that the implant 910 may possess a notch 970 between members 972 (posterior femoral implant condyles) in the areas approximately between the distal and posterior femoral condylar areas to accommodate the posterior cruciate ligament, as well as for other reasons. Because of the notch 970 between the posterior femoral condyles, the form cutter may not cut any material in the notch 970. Additionally, it may be advantageous to utilize a secondary form cutter as shown in FIG. 47 for use in creating a slot or slots in or near the distal area of the femur before or after it has been resected. Such a secondary cutter 790 would include engagement means 792 for engagement with driving means, and a shaft 794 carrying one or more cutters 796 for cutting slots into the femur through one or more of the resected surfaces thereof. Through the inclusion of an additional or adjunct cutting path in the pattern means, it would be advantageous to utilize the form cutter to create the aforementioned slots in the distal femur to accommodate the fixation fins which may be molded as an integral part of the interior surface of the implant 910. An implant with fixation fins is shown in FIG. 50. The fins 980 would provide mediolateral fixation stability in addition to that provided by the trochlear groove geometry of the implant 910. Further, the fins also provide for additional surface area for bony contact and ingrowth to increase implant fixation both in cemented and cementless total knee arthroplasty. FIG. 33b shows another embodiment of a milling bit, generally indicated at 754 for creating a curvilinear cutting path and curvilinear cutting profile in femur 756. In this embodiment, the transition from a first cutting area 984 to a second cutting area 986 is continuous and smooth. This milling bit 754 also includes spindles 981 at the ends thereof for engagement with pattern means to guide the milling bit along a cutting path. There are numerous advantages to the femoral component herein described. Foremost, it will allow for the thinnest implant cross-section possible (perhaps 3 mm to 6 mm in nominal thickness) and therefore necessitate the removal of the least amount of viable osseous tissue. This is especially critical in situations where the probability of revision surgery is high and the amount of viable bone available for revision implant fixation and apposition is a significant factor in the viability of the revision procedure. Since the form cutter configuration allows for similar amounts of tissue to be removed from the trochlear groove, the bony prominences surrounding the trochlear groove, the femoral condyles, and the other articular surfaces of the femur, the external geometry of the femoral implant can be optimized for patellofemoral articulation as well as tibiofemoral articulation. In essence, the kinematics of the artificial joint could be made to be as close as possible to that of a healthy, natural knee joint. In addition, the curvilinear geometry of the implant dramatically decreases the stress risers inherent in conventional rectilinear femoral implants and allows for a thinner cross-sectional geometry while potentially increasing the resistance of the implant to mechanical failure under fatigue or impact loading. The implant could have a relatively consistent cross-sectional thickness throughout the implant, or it could be varied as desired. The curvilinear geometry of the implant may also allow for an advantageous reduction in the flexural rigidity of the implant which may result in avoidance of the “stress-shielding” inherent in rigid implant designs. Stress shielding being a phenomenon that may occur when living bony tissue is prevented from experiencing the stresses necessary to stimulate its growth by the presence of a stiff implant. This phenomenon is analogous to the atrophy of muscle tissue when the muscle is not used, i.e., when a cast is placed on a person's arm the muscles in that arm gradually weaken for lack of use. Further, the curvilinear implant of the present invention could allow for the use of a ceramic material in its construction. Since ceramics are generally relatively weak in tension, existing ceramic implant designs contain very thick cross-sections which require a great deal of bony material removal to allow for proper implantation. Utilization of ceramics in the curvilinear implant would not only allow for the superior surface properties of ceramic, but also avoid the excessively thick cross-sections currently required for the use of the material. The curvilinear implant of the present invention could result in a less expensive femoral implant because of the reduced amount of material needed for the implant, as well as an improved, more natural, and even stronger knee replacement. It may desirable to vary the cross-section of the implant to assist in seating the implant, to increase the joint kinematics and to increase the strength and fit of the implant. The implant of the present invention could be fabricated of metal, plastic, or ceramic or any other material or combination thereof. Further, the thickness of the implants and the material required to fabricate the implant could be reduced as the implants are adapted to increasingly curvilinear surfaces. Also, it should be pointed out that such implants with curvilinear implant surfaces require less bone to be removed to obtain a fit between the implant and the bone. Finally, it should be noted that curvilinear milling bits hereinbefore described would work well for preparing a bone to receive an implant with curvilinear interior implant surface. Importantly, by using a milling bit having a curved profile, one can cut a femur to resemble the natural shape of the femur, i.e., the resected femur would include condylar bulges and a central notch. This would reduce the amount of bony material that must be removed from the femur while maintaining the structural integrity of the femur. Of course, any prosthetic implant used for attachment to a femur resected by the curved profile milling bit would necessarily have an appropriately contoured inner fixation surface for mating with contoured surface of the femur. Additionally, it should be noted that the curved profile milling bit could have one or more curvilinear bulges along the length thereof, as shown in FIGS. 35 and 49, or alternatively, could have one or more bulges discretely formed along the length thereof. The complete disclosures of the patents, patent applications and publications cited herein are incorporated by reference in their entirety as if each were individually incorporated. Various modifications and alterations to this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention. It should be understood that this invention is not intended to be unduly limited by the illustrative embodiments and examples set forth herein and that such examples and embodiments are presented by way of example only with the scope of the invention intended to be limited only by the claims set forth herein. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention This invention generally relates to methods and apparatus for femoral and tibial resection to allow for the interconnection or attachment of various prosthetic devices. 2. Related Art Different methods and apparatus have been developed in the past to enable a surgeon to remove bony material to create specifically shaped surfaces in or on a bone for various reasons including to allow for attachment of various devices or objects to the bone. Keeping in mind that the ultimate goal of any surgical procedure is to restore the body to normal function, it is critical that the quality and orientation of the cut, as well as the quality of fixation, and the location and orientation of objects or devices attached to the bone, is sufficient to ensure proper healing of the body, as well as appropriate mechanical function of the musculoskeletal structure. In total knee replacements, a series of planar and/or curvilinear surfaces, or “resections,” are created to allow for the attachment of prosthetic or other devices to the femur, tibia and/or patella. In the case of the femur, it is common to use the central axis of the femur, the posterior and distal femoral condyles, and/or the anterior distal femoral cortex as guides to determine the location and orientation of distal femoral resections. The location and orientation of these resections are critical in that they dictate the final location and orientation of the distal femoral implant. It is commonly thought that the location and orientation of the distal femoral implant are critical factors in the success or failure of the artificial knee joint. Additionally, with any surgical procedure, time is critical, and methods and apparatus that can save operating room time, are valuable. Past efforts have not been successful in consistently and/or properly locating and orienting distal femoral resections in a quick and efficient manner. The use of oscillating sawblade based resection systems has been the standard in total knee replacement for over 30 years. Due to their use of this sub-optimal cutting tool, the instrumentation systems all possess certain limitations and liabilities. Perhaps the most critical factor in the clinical success of TKA is the accuracy of the implant's placement. This can be described by the degrees of freedom associated with each implant; for the femoral component these include location and orientation that may be described as Varus-Valgus Alignment, Rotational Alignment, Flexion-Extension Alignment, A-P location, Distal Resection Depth Location, and Mediolateral Location. Conventional instrumentation very often relies on the placement of ⅛ or {fraction (3/16)} inch diameter pin or drill placement in the anterior or distal faces of the femur for placement of cutting guides. In the case of posterior referencing systems, the distal resection cutting guide is positioned by drilling two long drill bits into the anterior cortex. As these long drills contact the oblique surface of the femur they very often deflect, following the path of least resistance into the bone. As the alignment guides are disconnected from these cutting guides, the drill pins will “spring” to whatever position was dictated by their deflected course thus changing their designated, desired alignment to something less predictable and/or desirable. This kind of error is further compounded by the “tolerance stacking,” inherent in the use of multiple alignment guides and cutting guides. Another error inherent in these systems further adding to mal-alignment is deflection of the oscillating sawblade during the cutting process. The use of an oscillating sawblade is very skill intensive as the blade will also follow the path of least resistance through the bone and deflect in a manner creating variations in the cut surfaces which further contribute to prosthesis mal-alignment as well as poor fit between the prosthesis and the resection surfaces. Despite the fact that the oscillating saw has been used in TKA for more than 30 years, orthopedic salespeople still report incidences where poor cuts result in significant gaps in the fit between the implant and the bone. It is an often repeated rule of thumb for orthopedic surgeons that a “Well placed, but poorly designed implant will perform well clinically, while a poorly placed, well designed implant will perform poorly clinically.” One of the primary goals of the invention described herein is to eliminate errors of this kind to create more reproducible, consistently excellent clinical results in a manner that requires minimal manual skill on the part of the surgeon. None of the previous efforts of others disclose all of the benefits and advantages of the present invention, nor do the previous efforts of others teach or suggest all the elements of the present invention. | <SOH> OBJECTS AND SUMMARY OF THE INVENTION <EOH>Many of the specific applications of the method and apparatus of the present invention described herein apply to total knee replacement, a surgical procedure wherein planar surfaces and/or curvilinear surfaces must be created in or on bone to allow for proper attachment or implantation of prosthetic devices. However, it should be noted that it is within the scope of the present invention to apply the methods and apparatus herein described to the removal of any kind of material from bones in any other application where it is necessary, desirable or useful to remove material from bones. The apparatus of the present invention comprises a number of components including a positioning apparatus, a pattern apparatus and a cutting apparatus. The pattern apparatus is oriented and located by the use of the positioning apparatus which references the geometry of a bone to be resected and/or other anatomic landmarks. When used to resect a distal femur, the positioning apparatus also references the long axis of the femur. Once the positioning apparatus has been properly located, aligned, and initially fixed in place, the pattern apparatus may be attached thereto, and then adjusted according to the preferences of the surgeon utilizing the apparatus, and then the pattern apparatus can be rigidly fixed to a bone to be resected. This ensures the pattern apparatus is properly located and oriented prior to the use of the cutting apparatus to remove material from the bone. More specifically, when the method and apparatus of the present invention are used in connection with resecting a distal femur, the positioning apparatus is located and aligned utilizing the intramedullary canal of the femur, (thereby approximating the long axis of the femur), the distal surfaces of the femoral condyles, the anterior surface of the distal femur, and the posterior surfaces of the femoral condyles, which are referenced to indicate the appropriate location and orientation of the pattern apparatus. Fixation means may be used to fix the positioning apparatus, as well as the pattern apparatus to the distal femur. Means may be present in the positioning apparatus and/or pattern device for allowing the following additional adjustments in the location and orientation of the pattern device: 1. internal and external rotational adjustment; 2. varus and valgus angular adjustment; 3. anterior and posterior location adjustments; 4. proximal and distal location adjustment; and 5. flexion and extension angular adjustment. Cannulated screws, fixation nails or other fixation means may then be used to firmly fix the pattern apparatus to the distal femur. The positioning apparatus may then be disconnected from the pattern apparatus and removed from the distal femur. Thus, the location and orientation of the pattern apparatus is established. The pattern device possesses slot-like features, or a cutting path, having geometry that matches or relates to the desired geometry of the cut. When used in connection with resecting a knee, the cutting path resembles the interior profile of the distal femoral prosthesis. The cutting path guides the cutting apparatus to precisely and accurately remove material from the distal femur. Thus, the distal femur is thereby properly prepared to accept a properly aligned and located distal prosthesis. In preparing a patella, the pattern device may be an integral part of the positioning apparatus which is oriented and located by referencing the geometry of the patella itself as well as the structures of the patellofemoral mechanism to determine the location and orientation of a predominantly planar resection. The cutting device may then be employed to perform the resection of the patella by traversing the path dictated by the pattern device, thus dictating the final location and orientation of the patella prosthesis. The apparatus of the present invention comprises a number of components including an ankle clamp, an alignment rod, a fixation head, cutting guide clamps having an integral attachment mechanism, and a milling bit. The method of present invention includes the steps of attaching the ankle clamp about the ankle, interconnecting the distal end of the alignment rod with the ankle clamp, interconnecting the fixation head with the proximal end of the alignment rod, partially attaching the fixation head to the proximal tibia, aligning the alignment rod, completely attaching the fixation head to the proximal tibia, interconnecting the cutting guide clamps with the alignment rod, positioning the cutting guide clamps about the proximal tibia, securing the cutting guide clamps to the tibia at a proper location, removing the fixation head, and cutting the proximal tibia with the milling bit. The implant of the present invention has an outer bearing surface and an inner attachment surface. The outer bearing surface functions as a joint contact surface for the reconstructed bone. The inner attachment surface contacts a bone and is attached thereto. The inner attachment surface of the implant is curvilinear from an anterior to a posterior area of the femur, as is conventionally known, and is also curvilinear from a medial to a lateral area of the femur to approximate the shape of natural femur. The resection of the femur for accommodating the implant can be properly performed by a milling device employing one or more curvilinear milling bits. There are numerous advantages associated with the curvilinear implant of the present invention. First, it will allow for a very thin implant cross-section and therefore necessitate the removal of the least amount of viable osseous tissue. Accordingly, the kinematics of the artificial joint could be made to be as close as possible to that of a healthy, natural knee joint. In addition, the curvilinear geometry of the implant dramatically decreases the stress risers inherent in conventional rectilinear femoral implants and allows for a thinner cross-sectional geometry while potentially increasing the resistance of the implant to mechanical failure under fatigue or impact loading. Conversely, the curvilinear geometry of the implant may also allow for an advantageous reduction in the flexural rigidity of the implant which may result in avoidance of the “stress-shielding” inherent in rigid implant designs. This curvilinear implant of the present invention could also result in a less expensive femoral implant because of the reduced amount of material needed for the implant, as well as an improved, more natural, and even stronger knee replacement. The cross-section of the implant could be varied to assist in seating the implant and to increase the strength and fit of the implant. The implants of the present invention having curvilinear implant surfaces could be fabricated of metal, plastic, or ceramic or any other material. Further, the thickness of the implants and the material required to fabricate the implant could be reduced as the implants are adapted to increasingly curvilinear surfaces. The resected surfaces of a femur or other bone to accept the implant of the present invention could be prepared by the apparatus and method for resection shown and described in the prior related applications set forth herein, the entire disclosures of which are expressly incorporated herein by reference. The apparatus of the present invention comprises a number of components including a positioning and drill guide, a cutting guide and a cutting apparatus. The drill guide is used to create holes in the medial and lateral sides of the femur that correspond to the fixation features of the cutting guide. The cutting guide is oriented and located by inserting fixation nubs connected to the cutting guide into the medial and lateral holes in the femur. The cutting guide can then be further affixed to the femur. The cutting apparatus can then be used with the cutting guide to resect the femur. A conventional cutting block used with a conventional oscillating saw can also be positioned and interconnected with a femur in a similar manner using the drill guide of the present invention to create medial and lateral holes. A cutting guide can then be attached to the holes. A conventional cutting block can be interconnected with the cutting guide for attachment of the block to the femur. This invention can also be used in connection with a cortical milling system, i.e., a cutting system for providing a curvilinear cutting path and curvilinear cutting profile. Likewise, a tibial cutting guide can similarly be positioned on a tibia with a drill guide. It is a primary object of the present invention to provide an apparatus for properly resecting the distal human femur. It is also an object of this invention to provide an apparatus for properly orienting a resection of the distal human femur. It is an additional object of the resection apparatus of the present invention to properly locate the resection apparatus with respect to the distal human femur. It is even another object of the resection apparatus of the present invention to properly orient the resection apparatus with respect to the distal human femur. It is another object of the resection apparatus of the present invention to provide a guide device for establishing the location and orientation of the resection apparatus with respect to the distal human femur. It is still a further object of the resection apparatus of the present invention to lessen the chances of fatty embolisms. It is even a further object of this invention is to provide a resection apparatus capable of forming some or all of the resected surfaces of the distal human femur. It is another object of the resection apparatus of the present invention to provide an apparatus which is simple in design and precise and accurate in operation. It is also an intention of the resection apparatus of the present invention to provide a guide device for determining the location of the long axis of the femur while lessening the chances of fatty embolism. It is also an object of the resection apparatus of the present invention to provide a device to physically remove material from the distal femur in a pattern dictated by the pattern device. It is even another object of the resection apparatus of the present invention to provide a circular cutting blade for removing bone from the distal human femur to resection the distal human femur. It is also an object of the present invention to provide a method for easily and accurately resecting a distal human femur. These objects and others are met by the resection method and apparatus of the present invention. It is a primary object of the present invention to provide methods and apparatus for femoral and tibial resection. It is another object of the present invention to provide a method and apparatus for properly, accurately and quickly resecting a bone. It is also an object of this invention to provide a method and apparatus for properly orienting and locating a resection of a bone. It is a further object of the present invention to provide a method and apparatus to properly locate and orient the resection apparatus with respect to a bone. It is another object of the present invention to provide methods and apparatus for femoral and tibial resection which are simple in design and precise and accurate in operation. It is an additional object of the present invention to provide a method and apparatus to physically remove material from a bone in a pattern dictated by a pattern device and/or the geometry of a cutting device. It is a further object of the present invention to provide methods and apparatus for resecting a bone which allows one to visually inspect the location of the cut or cuts prior to making the cut or cuts. It is yet a further object of the present invention to provide a method and apparatus for resecting a bone which physically removes material from the bone along a surface dictated by a guide device. It is still a further object of the present invention to provide a method and apparatus for resecting a bone which employs a milling bit or form cutter for removing material from the bone. It is a further object of the present invention to provide methods and apparatus for femoral and tibial resection wherein the apparatus can be located on a bone to be cut in a quick, safe and accurate manner. It is a primary object of the present invention to provide a method and apparatus for properly resecting the proximal human tibia in connection with knee replacement surgery. It is also an object of the present invention to provide a method and apparatus for resecting the proximal human tibia which minimizes the skill necessary to complete the procedure. It is another object of the present invention to provide a method and apparatus for resecting the proximal human tibia which properly orients the resection of the proximal tibia. It is even another object of the present invention to provide a method and apparatus for resecting the proximal human tibia which is easy to use. It is yet another object of the present invention to provide a method and apparatus for resecting the proximal human tibia which orients the resection in accordance with what is desired in the art. It is still yet another object of the present invention to provide a method and apparatus for resecting the proximal human tibia which minimizes the amount of bone cut. It is a further object of the present invention to provide a method and apparatus for resecting the proximal human tibia which allows one to visually inspect the location of the cut prior to making the cut. It is even a further object of the present invention to provide a method and apparatus for resecting the proximal human tibia which is simple in design and precise and accurate in operation. It is yet a further object of the present invention to provide a method and apparatus for resecting the proximal human tibia which physically removes material from the proximal tibia along a surface dictated by a guide device. It is still a further object of the present invention to provide a method and apparatus for resecting the proximal human tibia which employs a milling bit for removing material from the proximal tibia. It is also an object of the present invention to provide a method and apparatus for resecting the proximal human tibia which includes a component which is operated, and looks and functions, like pliers or clamps. It is even another object of the present invention to provide an alternate embodiment of the method and apparatus for resecting the proximal human tibia which includes a component that resembles a U-shaped device for placing about the tibia. It is even a further object of the present invention to provide an alternate embodiment of the method and apparatus for resecting the proximal human tibia which includes a component that resembles an adjustable, square, U-shaped device for placing about the tibia. These objects and others are met and accomplished by the method and apparatus of the present invention for resecting the proximal tibia. It is a primary object of the present invention to provide a method and apparatus for removing material from bones. It is another object of the present invention to provide a method and apparatus for properly resecting bone. It is also an object of this invention to provide a method and apparatus for properly orienting a resection of a bone. It is a further object of the present invention to provide a method and apparatus to properly orient the resection apparatus with respect to a bone. It is an additional object of the present invention to provide a method and apparatus for properly locating a bone resection. It is a further object of the present invention to provide a method and apparatus to properly locate the resection apparatus with respect to a bone. It is even another object of the resection apparatus of the present invention to provide a guide device and method of use thereof for establishing the location and orientation of the resection apparatus with respect to a bone. It is an additional object of the present invention to provide a method and apparatus for making a curvilinear bone resection. It is still a further object of the resection apparatus of the present invention to lessen the chances of fatty embolisms. It is even further object of this invention to provide a method and apparatus capable of forming or re-forming some or all of the surfaces or resected surfaces of a bone. It is another object of the present invention to provide a method and apparatus which is simple in design and precise and accurate in operation. It is also an intention of the present invention to provide a method and apparatus for determining the location of the long axis of a bone while lessening the chances of fatty embolisms. It is also an object of the present invention to provide a method and apparatus to physically remove material from a bone in a pattern. It is an additional object of the present invention to provide a method and apparatus to physically remove material from a bone in a pattern dictated by a pattern device and/or the geometry of a cutting device. It is even another object of the resection apparatus of the present invention to provide a cylindrical or semi-cylindrical cutting device and method of use thereof for removing material from a bone. It is also an object of the present invention to provide a method and apparatus for easily and accurately resecting a bone. It is also an object of the present invention to provide a method and apparatus for resecting a bone which minimizes the manual skill necessary to complete the procedure. It is even another object of the present invention to provide a method and apparatus for resecting a bone which is easy to use. It is still yet another object of the present invention to provide a method and apparatus for resecting a bone which minimizes the amount of bone removed. It is a further object of the present invention to provide a method and apparatus for resecting a bone which allows one to visually inspect the location of the cut or cuts prior to making the cut or cuts. It is yet a further object of the present invention to provide a method and apparatus for resecting a bone which physically removes material from the bone along a surface dictated by a guide device. It is still a further object of the present invention to provide a method and apparatus for resecting a bone which employs a milling bit or form cutter for removing material from the bone. It is even another object of the present invention to provide a method and apparatus for removing material from a bone such that both the cutting path and cutting profile are predominantly curvilinear. It is a primary object of the present invention to provide an apparatus to properly replace damaged bony tissues. It is also an object of this invention to provide an apparatus to properly replace damaged bony tissues in joint replacement surgery. It is also an object of the present invention to provide an implant for the attachment to a distal femur in the context of knee replacement surgery. It is an additional object of the present invention to provide a method and apparatus for making a curvilinear implant. It is another object of the present invention to provide an implant having a reduced thickness to reduce the amount of material required to make the implant. It is even another object of the present invention to provide an implant having curvilinear fixation surfaces for increasing the strength of the implant. It is another object of the present invention to provide an implant having a fixation surface that is anterior-posterior curvilinear and mediolateral curvilinear. It is another object of the present invention to provide an implant that has a fixation surface that is shaped to resemble a natural distal femur. It is also an object of the present invention to provide an implant apparatus for allowing proper patellofemoral articulation. It is a further object of the present invention to provide for minimal stress shielding of living bone through reduction of flexural rigidity. It is an additional object of the present invention to provide an implant apparatus having internal fixation surfaces which allow for minimal bony material removal. It is another object of the present invention to provide an implant apparatus with internal fixation surfaces that minimize stress risers. It is another object of the present invention to provide an implant apparatus having internal fixation surfaces for precise fixation to curvilinear body resections. It is another object of the present invention to provide an implant apparatus having internal fixation surfaces for precise apposition to curvilinear body resections. It is another object of the present invention to provide an implant apparatus having internal fixation surfaces for curvilinear interior fixation geometries closely resembling the geometry of the external or articular geometry of the implant apparatus. It is also an object of this invention to provide a method and apparatus for properly locating and orienting a prosthetic implant with respect to a bone. It is another object of the present invention to provide an implant which is simple in design and precise and accurate in operation. It is also an object of the present invention to provide an implant which minimizes the manual skill necessary to complete the procedure. It is still yet another object of the present invention to provide an implant which minimizes the amount of bone removed. It is even another object of the present invention to provide a method and apparatus for removing material from a bone such that both the cutting path and cutting profile are predominantly curvilinear. | 20040113 | 20080318 | 20050310 | 96932.0 | 8 | HOFFMAN, MARY C | METHODS AND APPARATUS FOR FEMORAL AND TIBIAL RESECTION | UNDISCOUNTED | 1 | CONT-ACCEPTED | 2,004 |
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10,757,111 | ACCEPTED | Overburden rock core sample containment system | A compression cell for rock or soil core samples applies and restores lithostatic or overburden pressure to core samples extracted from wells drilled deep into the earth. A method of applying lithostatic pressure to a core sample is disclosed along with the apparatus which effects the application. The cell construction that maintains the litho static pressure and the process of utilizing the cell and sample under essentially deep earth ambient conditions are set forth. | 1. A process for loading a centrifuge rotor with overburden onto a contained rock core sample comprising the steps of: providing a containment cylinder closed at one end; providing a rubber liner closing one end of the containment cylinder around the inlet/outlet covering the sides of the containment cylinder; placing core sample interior of the liner and containment cylinder for compression by the rubber liner; providing a loading ring for compressing the rubber liner within the containment cylinder over the placed core sample; and, compressing the loading ring so that the rubber liner essentially reacts as a fluid to apply overburden pressure to the core sample. 2. The process for loading a centrifuge rotor with overburden onto a contained rock core sample according to claim 1 and including the further steps of: providing a locking mechanism connected between the loading ring and the containment cylinder for maintaining the loading ring compression on the rubber liner; and, locking the locking mechanism after the compressing step to statically maintained the overburden pressure on the core sample. 3. The process for loading a centrifuge rotor with overburden onto a contained rock core sample according to claim 1 and wherein the passing fluid through the core samples step includes: placing the containment cylinder in a centrifuge. 4. The process for loading a centrifuge rotor with overburden onto a contained rock core sample according to claim 1 and wherein the passing fluid through the core samples step includes: passing fluid from one inlet/outlet to the other inlet/outlet through core sample. 5. A chamber for containing a core sample with overburden pressure comprising: a containment cylinder closed at one end; a fluid inlet/outlet through the closed end of the containment cylinder; a rubber liner closing one end of the containment cylinder around the inlet/outlet covering the sides of the containment cylinder; a core sample interior of the liner and containment cylinder for compression by the rubber liner; a loading ring for compressing the rubber liner within the containment cylinder over the placed core sample, a fluid inlet/outlet through the loading ring; means compressing the loading ring so that the rubber liner essentially reacts as a fluid to apply lithostatic pressure to the core sample. 6. A process for testing fluid flow within a core sample taken from within the Earth at an elevation below ground having lithostatic pressure due to overburden comprising the steps of: applying the lithostatic pressure due to overburden independent of the overburden to the core sample; and, after applying the lithostatic pressure to the core sample, flowing fluid through the core sample to determine the fluid flow or capillary properties of the core sample. 7. A process for loading a cell contained rock core sample with overburden comprising the steps of: providing a containment cylinder closed at one end; providing a fluid inlet/outlet through the closed end of the containment cylinder; providing a rubber liner closing one end of the containment cylinder around the inlet/outlet covering the sides of the containment cylinder; placing core sample interior of the liner and containment cylinder for compression by the rubber liner; providing a loading ring for compressing the rubber liner within the containment cylinder over the placed core sample, providing a fluid inlet/outlet through the loading ring; compressing the loading ring in an hydraulic press so that the rubber liner essentially reacts as a fluid to apply lithostatic pressure to the core sample; and, passing fluid through the core sample to determine fluid flow characteristics of the sample at the lithostatic pressure. 8. The process for loading a centrifuge rotor with overburden onto a contained rock core sample according to claim 7 comprising the steps of: before the compressing step, heating the containment cylinder, rubber liner, and core sample to a temperature ambient to the rock core sample with overburden within its natural environment. | CROSS-REFERENCES TO RELATED APPLICATIONS NOT APPLICABLE STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT NOT APPLICABLE REFERENCE TO A “SEQUENCE LISTING,” A TABLE, OR A COMPUTER PROGRAM LISTING APPENDIX SUBMITTED ON A COMPACT DISK NOT APPLICABLE This invention relates to a compression cell for soil or rock core samples for applying and restoring lithostatic or overburden pressure to soil or rock core samples extracted from wells drilled deep into the earth. Specifically, a method of applying lithostatic pressure to a core sample is disclosed along with the apparatus which effects the application. The cell which maintains the litho static pressure and the process of utilizing the cell and sample under essentially deep earth ambient conditions are set forth. BACKGROUND OF THE INVENTION Underground rock pressures and underground fluid pressures differ radically. Underground rock pressures relate directly to overburden in and around the particular soil sample being tested. For example, in certain rock conditions where a sample is at a depth of about 10,000 feet, overburden pressures in the range to 8000 to 10,000 pounds per square inch may be experienced. Underground fluid pressures differ radically. As the soil usually defines paths through which fluid can flow, the fluid pressure is usually independent of the rock pressure. Taking the example of the core sample at 10,000 feet, and remembering the fluids have a density about one third of that of a rock, pressures in the range of 3000 to 4000 pounds per square inch may be present. Core samples are frequently extracted from deeply drilled the wells so that fluid flow properties within the rock of the core may be analyzed. Pore size, flow properties, capillary pressure and the like are all dependent upon the overburden pressure or lithostatic pressure upon a rock sample. If accurate testing of such core samples is to occur, the lithostatic pressures must be re-created. It is also known that the deeper one goes into the earth's mantle, the greater the temperature present in the ambient rock. Accordingly, if testing under the ambient conditions is to be re-created, it must be done under the same thermal conditions as well as lithostatic conditions as existed for the sample at its original depth within the earth. It is known to use centrifuges in the analysis of such core samples. See for example O'Meara Jr. et al. U.S. Pat. No. 4,567,373, Goodwill U.S. Pat. No. 4,740,077, Christiansen U.S. Pat. No. 4,817,423, Chen et al. U.S. Pat. No. 5,328,440, Ragazzini et al. U.S. Pat. No. 5,351,525, Spinler et al. U.S. Pat. No. 6,415,649, Fleury et al. U.S. Pat. No. 6,185,985, and Goglin et al. U.S. Pat. No. 6,490,531. In none of these references is litho static pressure created independently of fluid pressure. Discovery I have come to the realization that for the realistic testing of drill core samples, at least the litho static pressures must be re-created on the sample before accurate testing can occur. Preferably, I re-create both litho static pressures and thermal temperatures before testing. Only after both the litho static and thermal ambient are re-created, is it possible to conduct accurate testing. BRIEF SUMMARY OF THE INVENTION A process for loading a centrifuge rotor with overburden pressure or lithostatic pressure onto a rock core sample is disclosed. A titanium containment cylinder closed at one end forms the compression cell. A rubber liner closing one end of the containment cylinder also covers the sides of the containment cylinder. A core sample is placed interior of the liner so that the liner is between the containment cylinder and the core sample. A loading ring is utilized to compress the rubber liner within the containment cylinder over the placed core sample to uniformly compress the rubber liner and as a result the core sample from both ends as well as the cylindrical sides. Compression of the loading ring occurs so that the rubber liner essentially acts as a fluid to apply lithostatic pressure to the core sample uniformly on all sides. Provision is made to heat the core sample to ambient earth temperatures, preferably before compression occurs. A hydraulic press for applying the overburden or lithostatic pressure to the core sample is disclosed. Fluid inlet/outlets communicate through both ends of the containment cylinder to enable fluid measurements to be taken of the compressed core sample. The cell finds preferred use within a centrifuge or can be used independently for measurement of core sample fluid properties. Fluid, typically oil, gas, water, brine, or mixtures thereof, is passed through the core sample to determine hydrodynamic and hydrostatic characteristics of the rock core sample at the lithostatic temperature and pressure. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view in cross-section of a cell according to this invention illustrating an extracted core sample being compressed by a removable loading fixture with the rubber sleeve a centrally acting as a fluid for causing compression between the outer body of the containment cell and the inner and contained core sample; FIG. 2 is a sectional view of the cell of FIG. 1 placed within a hydraulic press for applying or releasing the overburden or lithostatic stress on the core sample; and, FIG. 3 is a schematic of the cell according to this invention being utilized within the centrifuge. DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 1, an overburden cell C is illustrated. Cell C is composed of an metal outer body 1 with rubber sleeve 8 containing rock core 4. Metal outer body 1 is cylindrical, closed at one and an open at the opposite end. Lower and upper metal end plugs 6, 7 which are equipped with fluid inlet/outlet ports 11 are within the interior of outer metal body 1. The reader will appreciate that the inlet/outlet ports 11 are typically larger than the largest particle size of the rock core sample 4. Typically, when overburden pressures are applied, the solids form a compression dome over the port 11 which allows substantially unimpeded fluid communication into and out of cell C. A push ring 2 at the open end of metal outer body 1 is used to compress the rubber sleeve when placed within a loading press. Rubber sleeve 8 acts essentially as a fluid on all sides and one end of rock core 4. It applies the requisite overburden pressure on to rock core 4. Specifically, removable loading fixture 12 acts on push ring 2 to apply compression to rubber sleeve 8. When pressure is applied to rubber sleeve 8 and rock core 4, locking closure 3 is screwed in after push ring 2 maintaining the pressure on the push ring. The axial loading nut (5) is adjusted prior to pressurizing to adjust for minor changes in rock core length. Anti-extrusion rings 9, 10 prevent the pressurized rubber sleeve from flowing into the opening between the outer body 1 and the end plugs 6, 7 when pressure is applied. The result is that rock core 4 as overburden pressure applied by rubber sleeve 8. By the expedient of adjusting the locking closure 3, the overburden or lithostatic pressure can be preserved on rock core 4. Referring to FIG. 2, overburden cell C a shown placed within the heating jacket J. Typically, heating jacket J is raised to a temperature ambient to that of the rock core 4 at the depth from which it is originally extracted. Thereafter, the overburden pressure is applied by having a loading ram 20, actuated by hydraulic pump 22 with gauge 23. Pressure is applied through loading ram 21 to removable loading fixture 12. Rubber sleeve 8 becomes fluid like and applies to rock core 4 the requisite overburden or lithostatic pressure. It will then be understood, that the core sample 4 is loaded with ambient overburden pressure and because of the heating previously described will also reside at ambient temperature. The reader will understand that upon cooling, cell. C will relieve some of the pressure on rock core 4. By the simple expedient of reheating the cell C, both the ambient temperature and lithostatic pressure can be restored. During loading of stress on rubber sleeve 8, it is important to pre-heat the sample and sleeve assembly to the temperature at which the test will be conducted. The pressurizing system should be left at conditions for a period of time to allow for some plastic flow of the sleeve into small voids and openings prior to locking in the rings and removing the system from the press. To remove the sample from the chamber it is necessary to re-apply the same stress to the rubber sleeve in order to unscrew the retaining ring. The primary uses of the cell here disclosed is in a centrifuge. Referring to FIG. 3, a centrifuge is schematically described in which a motor 30 drives rotor 32 about axis of rotation 34. Here, two cells C are shown undergoing centrifugation with in centrifuge chamber 36. Real-time fluid volume changes can be measured through the respective cells C by strobe light 38 through view port window 39. It will be just as well understood that the cell C can be utilized without placement into a centrifuge. Specifically, rock core 4 can either have fluid placed under static conditions within it or alternatively have fluid ambient to the rock core 4 removed from the core by a displacing fluid. From the above specification, it will be understood that I disclose at least four separate areas of utility. First, I have realized that overburden or lithostatic pressure is substantially independent of hydrostatic pressure. This being the case, I disclose a process of placing lithostatic pressure (and even temperature) on a sample first and then measuring its fluid flow characteristics second. Secondly, I utilize the rubber liner within my containment cell surrounding the core sample. This rubber liner acts essentially as a fluid and is able to uniformly impose on the core sample the ambient lithostatic pressure that the core sample has in its natural environment. Thus when fluid flow characteristics are measured, they can be measured at the original lithostatic pressure. It is also to be noted, that by preheating the core sample to the temperature found at its original depth within the earth, I can more or less completely emulate the conditions under which the core sample was extracted in the first instance. There are certain hysteresis effects which result from the cycling of temperatures and pressures on a rock core sample. These I cannot completely eliminate. However, by the following the disclosed testing routine, these effects can be minimized. Thirdly, I disclose an article. Simply stated, the cell without with the lithostatically loaded specimen is a useful article of commerce. Finally, the cell combined with a hydraulic press is a patentable article. | <SOH> BACKGROUND OF THE INVENTION <EOH>Underground rock pressures and underground fluid pressures differ radically. Underground rock pressures relate directly to overburden in and around the particular soil sample being tested. For example, in certain rock conditions where a sample is at a depth of about 10,000 feet, overburden pressures in the range to 8000 to 10,000 pounds per square inch may be experienced. Underground fluid pressures differ radically. As the soil usually defines paths through which fluid can flow, the fluid pressure is usually independent of the rock pressure. Taking the example of the core sample at 10,000 feet, and remembering the fluids have a density about one third of that of a rock, pressures in the range of 3000 to 4000 pounds per square inch may be present. Core samples are frequently extracted from deeply drilled the wells so that fluid flow properties within the rock of the core may be analyzed. Pore size, flow properties, capillary pressure and the like are all dependent upon the overburden pressure or lithostatic pressure upon a rock sample. If accurate testing of such core samples is to occur, the lithostatic pressures must be re-created. It is also known that the deeper one goes into the earth's mantle, the greater the temperature present in the ambient rock. Accordingly, if testing under the ambient conditions is to be re-created, it must be done under the same thermal conditions as well as lithostatic conditions as existed for the sample at its original depth within the earth. It is known to use centrifuges in the analysis of such core samples. See for example O'Meara Jr. et al. U.S. Pat. No. 4,567,373, Goodwill U.S. Pat. No. 4,740,077, Christiansen U.S. Pat. No. 4,817,423, Chen et al. U.S. Pat. No. 5,328,440, Ragazzini et al. U.S. Pat. No. 5,351,525, Spinler et al. U.S. Pat. No. 6,415,649, Fleury et al. U.S. Pat. No. 6,185,985, and Goglin et al. U.S. Pat. No. 6,490,531. In none of these references is litho static pressure created independently of fluid pressure. Discovery I have come to the realization that for the realistic testing of drill core samples, at least the litho static pressures must be re-created on the sample before accurate testing can occur. Preferably, I re-create both litho static pressures and thermal temperatures before testing. Only after both the litho static and thermal ambient are re-created, is it possible to conduct accurate testing. | <SOH> BRIEF SUMMARY OF THE INVENTION <EOH>A process for loading a centrifuge rotor with overburden pressure or lithostatic pressure onto a rock core sample is disclosed. A titanium containment cylinder closed at one end forms the compression cell. A rubber liner closing one end of the containment cylinder also covers the sides of the containment cylinder. A core sample is placed interior of the liner so that the liner is between the containment cylinder and the core sample. A loading ring is utilized to compress the rubber liner within the containment cylinder over the placed core sample to uniformly compress the rubber liner and as a result the core sample from both ends as well as the cylindrical sides. Compression of the loading ring occurs so that the rubber liner essentially acts as a fluid to apply lithostatic pressure to the core sample uniformly on all sides. Provision is made to heat the core sample to ambient earth temperatures, preferably before compression occurs. A hydraulic press for applying the overburden or lithostatic pressure to the core sample is disclosed. Fluid inlet/outlets communicate through both ends of the containment cylinder to enable fluid measurements to be taken of the compressed core sample. The cell finds preferred use within a centrifuge or can be used independently for measurement of core sample fluid properties. Fluid, typically oil, gas, water, brine, or mixtures thereof, is passed through the core sample to determine hydrodynamic and hydrostatic characteristics of the rock core sample at the lithostatic temperature and pressure. | 20040113 | 20051206 | 20050714 | 98182.0 | 0 | CYGAN, MICHAEL T | OVERBURDEN ROCK CORE SAMPLE CONTAINMENT SYSTEM | SMALL | 0 | ACCEPTED | 2,004 |
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10,757,134 | ACCEPTED | Self-identifying antenna system | An antenna system is disclosed, to be used with a radio component particularly a wireless access point or bridge. The present system includes an antenna element for transmitting and receiving signals at radio frequencies. An antenna connector is provided for establishing a signal connection between the antenna element and a radio component. An electronic serialization component is provided for indicating one or more predetermined antenna characteristics. This component is adapted to read out the predetermined antenna characteristics through the antenna connector to the radio component. | 1. An antenna system comprising: an antenna element for transmitting and receiving signals at radio frequencies; an antenna connector for establishing a signal connection between the antenna element and a radio component; an electronic serialization component for indicating at least one predetermined antenna characteristic, and adapted to read out the predetermined antenna characteristics through the antenna connector to the radio component; 2. The antenna system of claim 1 wherein the predetermined antenna characteristics are selected from a group including at least one of: antenna gain, operational frequency band, product model number and type of connection. 3. The antenna system of claim 1 wherein the electronic serialization component comprises a circuit, wherein the predetermined antenna characteristics are coded into the circuit. 4. The antenna system of claim 3 wherein the circuit comprises a semiconductor memory chip. 5. The antenna system of claim 3 wherein the circuit comprises a threshold detection circuit for detecting a predetermined voltage threshold, corresponding to a predetermined antenna gain. 6. The antenna system of claim 1 wherein the antenna element comprises a plurality of antenna elements in an antenna array. 7. A wireless communication device comprising: a radio component for exchanging wired electronic signals with wireless signals; an antenna system comprising: an antenna element for respectively transmitting and receiving at radio frequencies the wireless signals exchanged with the radio component; an antenna connector for establishing a signal connection between the antenna and the radio component; an electronic serialization component for indicating predetermined antenna characteristics, and adapted to read out the predetermined antenna characteristics through the antenna connector to the radio component. 8. The wireless communication device of claim 7 wherein the predetermined antenna characteristics are selected from a group including at least one of: antenna gain, operational frequency band, product model number and type of connection. 9. The wireless communication device of claim 7 wherein the electronic serialization component comprises a circuit, wherein the predetermined antenna characteristics are coded into the circuit. 10. The wireless communication device of claim 7 wherein the circuit comprises a semiconductor memory chip. 11. The wireless communication device of claim 7 wherein the circuit comprises a threshold detection circuit for detecting a predetermined voltage threshold, corresponding to a predetermined antenna gain. 12. The wireless communication device of claim 7 wherein the antenna element comprises a plurality of antenna elements in an antenna array. 13. The wireless communications device of claim 7 wherein the antenna system is an integrally mounted antenna system. 14. The wireless communications device of claim 7 wherein the antenna system is an externally mounted antenna system. 15. The wireless communications device of claim 7 wherein the radio component comprises at least one algorithm for varying at least one operational parameter in response to the predetermined antenna characteristics. 16. The wireless communications device of claim 15 wherein the predetermined antenna characteristics comprise antenna gain, and wherein the radio component algorithm sets antenna power so as to maintain antenna gain. 17. The wireless communications device of claim 7 wherein the radio component and antenna system are included in at least one of a wireless access point and bridge for use with wireless local area network. 18. A method of antenna operation comprising: receiving an identification stream from an antenna serialization component; processing the identification stream so as to identify at least one predetermined antenna characteristics; varying at least one operational parameters of a radio component in response to the at least one predetermined antenna characteristic. 19. The method of claim 18 wherein the steps of processing and varying are implemented by an algorithm within the radio component. 20. The method of claim 18 wherein the at least one predetermined antenna characteristic comprises a predetermined antenna gain and the at least one operational parameter respectively comprises a predetermined radio component maximum output power level corresponding to the predetermined antenna gain. 21. The method of claim 18 wherein the at least one predetermined antenna characteristic comprises a predetermined radio component operational frequency range. 22. The method of claim 18 wherein the at least one predetermined antenna characteristic comprises a predetermined antenna component number, and wherein the at least one operational parameter respectively comprises a command to disable the radio component if the predetermined antenna component number is not indicated. 23. The method of claim 18 further comprising a step of reading predetermined antenna characteristics over a network by a network administrator in a remote location. 24. The method of claim 18 further comprising a step of reprogramming the predetermined antenna characteristics in a serialization component via a network. 25. A computer usable medium having computer readable program code embodied therein for effecting the radio component operation, the computer readable program code in a computer program product comprising: instructions for receiving an identification stream from an antenna serialization component; instructions for processing the identification stream so as to identify at least one predetermined antenna characteristics; instructions for varying at least one operational parameters of a radio component in response to the at least one predetermined antenna characteristic. 26. The computer program product of claim 25 wherein the instructions for processing and varying are implemented by an algorithm within the radio component. 27. The computer program product of claim 25 wherein the at least one predetermined antenna characteristic comprises a predetermined antenna gain and the at least one operational parameter respectively comprises a predetermined radio component power output level corresponding to the predetermined antenna gain. 28. The computer program product of claim 25 wherein the at least one predetermined antenna characteristic comprises a predetermined radio component operational frequency range. 29. The computer program product of claim 25 wherein the at least one predetermined antenna characteristic comprises a predetermined antenna component number, and wherein the at least one operational parameter respectively comprises a command to disable the radio component if the predetermined antenna component number is not indicated. 30. The computer program product of claim 25 further comprising instructions for reading predetermined antenna characteristics over a network by a network administrator in a remote location. 31. The computer program product of claim 25 further comprising instructions for reprogramming the predetermined antenna characteristics in a serialization component via a network. | BACKGROUND OF THE INVENTION The present system is directed to the field of antenna technology for wireless communication. The present system has special applicability in a wireless access point (AP) or wireless bridge (BR) of the type used with a wireless local area network (WLAN.) The Federal Communications Commission (FCC) and other regulatory agencies worldwide place a number of restrictions on intentional radiator components such as transmitting radio antennas. In one instance, the FCC requires that radio components for WLAN devices operate at a fixed maximum power level, so as to maintain compliance with an approved antenna gain. This power level is established for each WLAN device during the installation of a WLAN. In order to insure compliance with the power/gain requirements, the FCC requires that a professional, licensed installer be contracted to install these components, and that once installed the end user has no access to increase the maximum available power level set by the professional installer. In a further effort to insure compliance, the FCC requires that intentional radiators such as WLAN devices be designed so that no antenna may be used with the device other than the one specifically provided. Most manufactures accomplish this by providing a non-standard, proprietary reverse-TNC connector, for joining the radio component to the antenna. This special connector adds expense to the AP, while providing no additional functionality or other benefit beyond compliance with regulations. SUMMARY OF THE INVENTION The difficulties and drawbacks of previous-type systems are overcome by the present antenna system, to be used with a radio component particularly a WLAN device. The present system includes an antenna element for transmitting and receiving signals at radio frequencies. An antenna connector is provided for establishing a signal connection between the antenna element and a radio component. An electronic serialization component is provided for indicating one or more predetermined antenna characteristics. This component is adapted to read out the predetermined antenna characteristics through the antenna connector to the radio component. As will be realized, the invention is capable of other and different embodiments and its several details are capable of modifications in various respects, all without departing from the invention. Accordingly, the drawing and description are to be regarded as illustrative and not restrictive. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram representing the structure of a preferred embodiment in accordance with the present system. FIG. 2 is a flow chart illustrating the method of varying operational parameters in accordance with the present system. DETAILED DESCRIPTION OF THE EMBODIMENTS As shown in FIG. 1, an antenna system 10 is disclosed that cooperates with a wireless transceiver 20, preferably for exchanging wireless telecommunications in the radio frequency (RF) band of the electromagnetic spectrum. The antenna system 10 includes an antenna element 12 for transmitting and receiving signals at radio frequencies. In the preferred embodiment, the present antenna system 10 is used in accordance with a wireless access point or bridge of the type used with a WLAN. In such an embodiment, it is contemplated that the present system would communicate over one or both of the 2.4 GHz and 5 GHz wireless bands, in accordance with the IEEE 802.11 protocols. Of course, it should be appreciated that the present embodiments could be used with any wireless communication device, operating under any wireless band, including large communications stations and small, hand-held units, all without departing from the scope of the invention. The present antenna element 12 cooperates with an electronic serialization component 14 for indicating one or more predetermined antenna characteristics. The electronic serialization component 14 can be any suitable type of identification circuit, where the predetermined antenna characteristics are coded into or by the circuit. The predetermined antenna characteristics can be any suitable type of information that can be used to identify the antenna or its properties. For example, the characteristics can include the level of antenna gain and its associated maximum output power, desired operation of the antenna, including selecting a preferred operational frequency band. The characterizing can also include a product model identification number, including the manufacturer and the specific radio components and type of connection with which the antenna 12 is permitted to operate, in accordance with worldwide regulatory requirements. Any other suitable identification characteristics could also be employed, without departing from the invention. In the preferred embodiment, the electronic serialization component 14 is a programmable circuit, such a semiconductor memory chip. In the preferred embodiment, a Dallas Semiconductor DS2502P memory chip could be used, though any other suitable component(s) could be used. However, a hard-coded circuit may also be used, such as an analog or digital threshold detection circuit for detecting a desired voltage threshold, corresponding to a predetermined limit of antenna gain. Any other suitable circuit can be provided for detecting any other physical property of the signal, such as current, frequency, waveform, and any other suitable characteristic that might be detected. It should also be appreciated that the antenna system can include any number of antenna elements in an antenna array, to establish any desired radiation pattern or any sort of sectorized communications service area, such as is known in the art. In the preferred embodiment, the serialization component 14 is an integral part of an antenna system that can be connected to the wireless transceiver 20, so as to provide an externally-mounted antenna system 10. The antenna system 10 can also be internally-mounted into a transceiver housing, so as to be a part of an internal unit. In any event, an antenna connector 16 is used for establishing a signal connection between the antenna element 12 and a radio component 22 within the transceiver 20. The serialization component 14 is mounted “downstream” of the antenna element 12. The antenna connector 16 can be a coaxial cable, or any other suitable means for establishing a signal connection with the radio component 22. In operation, as shown in FIG. 2 the serialization component 14 is configured to “read out” the programmed antenna characteristics, so as to send an “identification stream” through the antenna connector 16 to the radio component 22. The radio component 22 includes an algorithm and suitable hardware for receiving and processing the signal from the serialization component 14, so as to vary one or more operational parameters in response to antenna characteristics. For example, if a required antenna gain is indicated the radio component algorithm automatically sets a limit on maximum power as indicated by the antenna element 12, so as to maintain compliance with the FCC-mandated antenna gain. In this way, a WLAN can now be installed without a lot of “fine-tuning” of maximum output power by professional installers. By enabling antenna gain to be automatically detected by the algorithm, the present system could feasibly be installed by average maintenance personnel. It is hoped that the present invention would simply rollout of a WLAN, and possibly lead to the revision of the FCC installation requirements. The present algorithm can be adapted to read out frequency specifications from the serialization component 14. For example, in certain types of high-gain antennas, it is required that the end channels of the band not be used, to avoid interference encroachment at the adjoining bands. By specifying which channels cannot be used, the present serialization component 14 can instruct the radio component 22 to not transmit signals over prohibited frequency channels. In this way, the present system can enable a single antenna system to replace a number of different antenna systems currently manufactured and marketed. For example, in 5 GHz antenna systems, integral antenna systems are known that work in all bands, including the unlicensed UNII-1 band, which has a 200 mW operational limit. External antenna systems are known that work in all bands other than UNII-1. These antennas are otherwise similar, but two products are sold for each respective applications with the present systems, it is contemplated that a single antenna product “part number” can be manufactured, with the requirements for external and internal antennas programmed into the serialization component 14. In this way, the present system can reduce manufacturing, packaging, inventory and distribution thereby realizing a considerable improvement in efficiency. The present system also has the potential to alleviate the requirement that proprietary antennas be used with proprietary transceiver components. Rather than use a unique type of electrical connector between the antenna and the radio component, the present radio component can be programmed to not function unless the correct product model number is read out of the serialization component 14. Similarly, the circuit of the serialization component 14 can include a switch, physical or programmatic, which disables the radio unless it identifies the correct type of antenna component 12. In this way, compliance with regulatory standards is obtained without incurring the additional expense of manufacturing a proprietary antenna connector component. In addition to facilitating FCC compliance, the present system allows for network management functionality. Since the antennas can “talk” to the access point or bridge, their predetermined antenna characteristics can also be read by a network administrator in a remote location. This can assist in inventory control and technical support of the WLAN, since all the antennas in a WLAN can be read out. In this way, compliance can be assured at the administrative level, and any failures or other operational variations can be detected. The present system also offers the flexibility of reprogramming one or more serialization components via the network. In a system upgrade, new access points can be added to a WLAN, e.g. for distributing sectorized coverage of a conference room over a number of newly added wireless channels. In this event, it may be desirable to remotely reprogram the serialization component “on the fly” over the network, to select a new maximum output power and/or channel limitation. In this way, the present system also allows greater control and flexibility of network management. As described hereinabove, the present invention solves many problems associated with previous type devices. However, it will be appreciated that various changes in the details, materials and arrangements of parts which have been herein described and illustrated in order to explain the nature of the invention may be made by those skilled in the area within the principle and scope of the invention will be expressed in the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>The present system is directed to the field of antenna technology for wireless communication. The present system has special applicability in a wireless access point (AP) or wireless bridge (BR) of the type used with a wireless local area network (WLAN.) The Federal Communications Commission (FCC) and other regulatory agencies worldwide place a number of restrictions on intentional radiator components such as transmitting radio antennas. In one instance, the FCC requires that radio components for WLAN devices operate at a fixed maximum power level, so as to maintain compliance with an approved antenna gain. This power level is established for each WLAN device during the installation of a WLAN. In order to insure compliance with the power/gain requirements, the FCC requires that a professional, licensed installer be contracted to install these components, and that once installed the end user has no access to increase the maximum available power level set by the professional installer. In a further effort to insure compliance, the FCC requires that intentional radiators such as WLAN devices be designed so that no antenna may be used with the device other than the one specifically provided. Most manufactures accomplish this by providing a non-standard, proprietary reverse-TNC connector, for joining the radio component to the antenna. This special connector adds expense to the AP, while providing no additional functionality or other benefit beyond compliance with regulations. | <SOH> SUMMARY OF THE INVENTION <EOH>The difficulties and drawbacks of previous-type systems are overcome by the present antenna system, to be used with a radio component particularly a WLAN device. The present system includes an antenna element for transmitting and receiving signals at radio frequencies. An antenna connector is provided for establishing a signal connection between the antenna element and a radio component. An electronic serialization component is provided for indicating one or more predetermined antenna characteristics. This component is adapted to read out the predetermined antenna characteristics through the antenna connector to the radio component. As will be realized, the invention is capable of other and different embodiments and its several details are capable of modifications in various respects, all without departing from the invention. Accordingly, the drawing and description are to be regarded as illustrative and not restrictive. | 20040114 | 20070130 | 20050714 | 68060.0 | 0 | HANNON, CHRISTIAN A | SELF-IDENTIFYING ANTENNA SYSTEM | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,757,156 | ACCEPTED | Autonomic method and apparatus for local program code reorganization using branch count per instruction hardware | A method, apparatus, and computer instructions for local program reorganization using branch count per instruction hardware. In a preferred embodiment, a hardware counter is used in the present invention to count the number of times a branch is taken when branch instructions are executed. Branch count statistics generated from the hardware counters are available to a program in order to analyze whether code reorganization is necessary. If reorganization is necessary, the program autonomically reorganizes instructions locally at run time to allow more instructions to be executed prior to taking a branch, so that the number of branches taken is minimized without modifying underlying program code. | 1. A method of autonomically reorganizing code of a computer program, comprising the steps of: monitoring branch count per instruction statistics, wherein the branch count per instruction statistics are generated from the results of a set of hardware counters that count branches taken per instruction of the computer program; determining whether a block of code is to be reorganized, wherein the block of code comprises a set of instructions; in response to the step of determining, locally reorganizing the block of code such that fewer branches are taken. 2. The method of claim 1, wherein the step of determining whether a block of code is to be reorganized is based on the branch count per instruction statistics. 3. The method of claim 1, wherein prior to the step of reorganizing the block of code, execution of the computer program is halted. 4. The method of claim 1, wherein reorganization of the block of code results in instructions of the block of code being more contiguous. 5. The method of claim 1, wherein reorganizing the block of code is performed locally by modifying an if/then/else clause condition. 6. The method of claim 1, wherein reorganization of the block of code is performed locally by switching a then/else statement of an if/then/else clause of a branch instruction of the block of code. 7. A computer system for autonomically reorganizing code of a computer program, comprising: a set of hardware counters associated with a set of branch instructions of a computer program, wherein the hardware counters are used to generate branch count per instruction statistics; a block of code including at least one branch instruction of the set of branch instructions; wherein the block of code is locally reorganized; and wherein the branch count per instruction statistics are used to determine whether to autonomically reorganize a block of code. 8. The system of claim 7, wherein the block of code is locally reorganized by modifying an if/then/else clause condition. 9. The system of claim 7, wherein the block of code is locally reorganized by switching a then/else statement of an if/then/else clause of an instruction of the block of code. 10. The system of claim 7, wherein execution of the computer program is halted while the block of code is locally reorganized. 11. The system of claim 7, wherein local reorganization of the block of code results in fewer branches being taken during execution of the program. 12. A computer program product in a computer readable medium for autonomically reorganizing code of a computer program, comprising: first instructions for monitoring branch count per instruction statistics, wherein the branch count per instruction statistics are generated from the results of a set of hardware counters that count branches taken per instruction of the computer program; second instructions for determining whether a block of code is to be reorganized, wherein the block of code comprises a set of instructions; third instructions for, in response to the step of determining, locally reorganizing the block of code such that fewer branches are taken. 13. The computer program product of claim 12, wherein determining whether a block of code is to be reorganized is based on the branch count per instruction statistics. 14. The computer program product of claim 12, wherein prior to reorganizing the block of code, execution of the computer program is halted. 15. The computer program product of claim 12, wherein reorganizing the block of code results in instructions of the block of code being more contiguous. 16. The computer program product of claim 12, wherein reorganizing the block of code is performed locally by modifying an if/then/else clause condition. 17. The computer program product of claim 12, wherein reorganizing the block of code is performed locally by switching a then/else statement of an if/then/else clause of an instruction of the block of code. | CROSS REFERENCE TO RELATED APPLICATIONS The present invention is related to the following applications entitled “Method and Apparatus for Counting Instruction Execution and Data Accesses”, Ser. No. ______, attorney docket no. AUS920030477US1, filed on Sep. 30, 2003; “Method and Apparatus for Selectively Counting Instructions and Data Accesses”, Ser. No. ______, attorney docket no. AUS920030478US1, filed on Sep. 30, 2003; “Method and Apparatus for Generating Interrupts Upon Execution of Marked Instructions and Upon Access to Marked Memory Locations”, Ser. No. ______, attorney docket no. AUS920030479US1, filed on Sep. 30, 2003; “Method and Apparatus for Counting Data Accesses and Instruction Executions that Exceed a Threshold”, Ser. No. ______, attorney docket no. AUS920030480US1, filed on Sep. 30, 2003; “Method and Apparatus for Counting Execution of Specific Instructions and Accesses to Specific Data Locations”, Ser. No. ______, attorney docket no. AUS920030481US1, filed on Sep. 30, 2003; “Method and Apparatus for Debug Support for Individual Instructions and Memory Locations”, Ser. No. ______, attorney docket no. AUS920030482US1, filed on Sep. 30, 2003; “Method and Apparatus to Autonomically Select Instructions for Selective Counting”, Ser. No. ______, attorney docket no. AUS920030483US1, filed on Sep. 30, 2003; “Method and Apparatus to Autonomically Count Instruction Execution for Applications”, Ser. No. ______, attorney docket no. AUS920030484US1, filed on Sep. 30, 2003; “Method and Apparatus to Autonomically Take an Exception on Specified Instructions”, Ser. No. ______, attorney docket no. AUS920030485US1, filed on Sep. 30, 2003; “Method and Apparatus to Autonomically Profile Applications”, Ser. No. ______, attorney docket no. AUS920030486US1, filed on Sep. 30, 2003; “Method and Apparatus for Counting Instruction and Memory Location Ranges”, Ser. No. ______, attorney docket no. AUS920030487US1, filed on Sep. 30, 2003; “Autonomic Method and Apparatus for Counting Branch Instructions to Improve Branch Predictions”, Ser. No. ______, attorney docket no. AUS920030550US1, filed on ______; and “Autonomic Method and Apparatus for Hardware Assist for Patching Code”, Ser. No. ______, attorney docket no. AUS920030551US1, filed on ______. All of the above related applications are assigned to the same assignee, and incorporated herein by reference. BACKGROUND OF THE INVENTION 1. Technical Field The present invention relates generally to an improved data processing system and, in particular, to a method and system for improving performance of the processor in a data processing system. Still more particularly, the present invention relates to a method, apparatus, and computer instructions for local code reorganization using branch count per instruction hardware. 2. Description of Related Art In a computer system, branch prediction is a technique used to guess whether a conditional branch will be taken or not. If it is predicted that a conditional branch will be taken, the processor will prefetch code for the branch instruction from the appropriate location. A speculative execution is performed to take advantage of branch prediction by executing the instruction before the processor is certain that they are in the correct execution path. For example, if a branch is taken more than 90 percent of the time, it is predicted to be taken and the processor will prefetch the code prior to reaching the branch instruction. A branch instruction may be conditional or unconditional. A conditional branch instruction causes an instruction to branch or jump to another location of code if a specified condition is satisfied. If the condition is not satisfied, the next instruction in sequential order is fetched and executed. A special fetch/decode unit in a processor uses a branch prediction algorithm to predict the direction and outcome of the instructions being executed through multiple levels of branches, calls, and returns. Branch prediction enables the processor to keep the instruction pipeline full while running at a high rate of speed. In conventional computer systems, branch prediction is based on branch prediction software that uses branch statistics and other data to minimize stalls caused by delays in fetching instructions that branch to nonlinear memory locations. In some cases, the code of a program can be locally reorganized to improve performance. Such code reorganization is typically based on software generated statistics to determine whether local code reorganization is advantageous. However, such software generated statistics require use of resources that may in some cases be better allocated to other tasks, while hardware resources that may be present go unused, resulting in an inefficient use of overall resources. Therefore, it would be advantageous to have an improved method, apparatus, and computer instructions for providing branch count per instruction statistics that allow a program to autonomically perform local code reorganization, so that processor performance may be optimized. SUMMARY OF THE INVENTION The present invention provides a method, apparatus, and computer instructions for local program code reorganization at run time using branch count per instruction hardware. In a preferred embodiment, the mechanism of the present invention allows a program to analyze branch count per instruction statistics generated using hardware counters. The branch count per instruction statistics identify the number of times a branch is actually taken when a branch instruction is executed. Based on the branch count per instruction statistics, the program autonomically determines whether the code requires reorganization in order to optimize processor performance. The program may reorganize the code by swapping location of an “if/then/else” statement locally so that more instructions may be executed contiguously prior to taking the branch. This run time code reorganization minimizes the number of branches taken without modifying the underlying application code. BRIEF DESCRIPTION OF THE DRAWINGS The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: FIG. 1 is an exemplary block diagram of a data processing system in which the present invention may be implemented; FIG. 2 is an exemplary block diagram of a processor system for processing information in accordance with a preferred embodiment of the present invention; FIG. 3A is an exemplary diagram illustrating example branch statistic fields in accordance with a preferred embodiment of the present invention; FIG. 3B is an exemplary diagram illustrating an example branch instruction in accordance with a preferred embodiment of the present invention; FIG. 4 is an exemplary diagram illustrating an example meta data in accordance with a preferred embodiment of the present invention; FIG. 5 is an exemplary diagram illustrating program code reorganization by swapping “if”, “then”, “else” statements at run time in accordance with a preferred embodiment of the present invention; and FIG. 6 is a flowchart process outlining an exemplary process for local program code reorganization using branch count per instruction hardware at run time in accordance with a preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention provides a method, apparatus, and computer instructions for local program code reorganization at run time using branch count per instruction hardware. The present invention provides hardware counters to count the number of times a branch is actually taken when a branch instruction is executed. The present invention may be implemented in a computer system. The computer system may be a client or a server in a client-server environment that is interconnected over a network. With reference now to FIG. 1, an exemplary block diagram of a data processing system is shown in which the present invention may be implemented. Client 100 is an example of a computer, in which code or instructions implementing the processes of the present invention may be located. Client 100 employs a peripheral component interconnect (PCI) local bus architecture. Although the depicted example employs a PCI bus, other bus architectures such as Accelerated Graphics Port (AGP) and Industry Standard Architecture (ISA) may be used. Processor 102 and main memory 104 are connected to PCI local bus 106 through PCI bridge 108. PCI bridge 108 also may include an integrated memory controller and cache memory for processor 102. Additional connections to PCI local bus 106 may be made through direct component interconnection or through add-in boards. In the depicted example, local area network (LAN) adapter 110, small computer system interface SCSI host bus adapter 112, and expansion bus interface 114 are connected to PCI local bus 106 by direct component connection. In contrast, audio adapter 116, graphics adapter 118, and audio/video adapter 119 are connected to PCI local bus 106 by add-in boards inserted into expansion slots. Expansion bus interface 114 provides a connection for a keyboard and mouse adapter 120, modem 122, and additional memory 124. SCSI host bus adapter 112 provides a connection for hard disk drive 126, tape drive 128, and CD-ROM drive 130. Typical PCI local bus implementations will support three or four PCI expansion slots or add-in connectors. An operating system runs on processor 102 and is used to coordinate and provide control of various components within data processing system 100 in FIG. 1. The operating system may be a commercially available operating system such as Windows XP, which is available from Microsoft Corporation. An object oriented programming system such as Java may run in conjunction with the operating system and provides calls to the operating system from Java programs or applications executing on client 100. “Java” is a trademark of Sun Microsystems, Inc. Instructions for the operating system, the object-oriented programming system, and applications or programs are located on storage devices, such as hard disk drive 126, and may be loaded into main memory 104 for execution by processor 102. Those of ordinary skill in the art will appreciate that the hardware in FIG. 1 may vary depending on the implementation. Other internal hardware or peripheral devices, such as flash read-only memory (ROM), equivalent nonvolatile memory, or optical disk drives and the like, may be used in addition to or in place of the hardware depicted in FIG. 1. Also, the processes of the present invention may be applied to a multiprocessor data processing system. For example, client 100, if optionally configured as a network computer, may not include SCSI host bus adapter 112, hard disk drive 126, tape drive 128, and CD-ROM 130. In that case, the computer, to be properly called a client computer, includes some type of network communication interface, such as LAN adapter 110, modem 122, or the like. As another example, client 100 may be a stand-alone system configured to be bootable without relying on some type of network communication interface, whether or not client 100 comprises some type of network communication interface. As a further example, client 100 may be a personal digital assistant (PDA), which is configured with ROM and/or flash ROM to provide non-volatile memory for storing operating system files and/or user-generated data. The depicted example in FIG. 1 and above-described examples are not meant to imply architectural limitations. The processes of the present invention are performed by processor 102 using computer implemented instructions, which may be located in a memory such as, for example, main memory 104, memory 124, or in one or more peripheral devices 126-130. Turning next to FIG. 2, an exemplary block diagram of a processor system for processing information is depicted in accordance with a preferred embodiment of the present invention. Processor 210 may be implemented as processor 102 in FIG. 1. In a preferred embodiment, processor 210 is a single integrated circuit superscalar microprocessor. Accordingly, as discussed further herein below, processor 210 includes various units, registers, buffers, memories, and other sections, all of which are formed by integrated circuitry. Also, in the preferred embodiment, processor 210 operates according to reduced instruction set computer (“RISC”) techniques. As shown in FIG. 2, system bus 211 is connected to a bus interface unit (“BIU”) 212 of processor 210. BIU 212 controls the transfer of information between processor 210 and system bus 211. BIU 212 is connected to an instruction cache 214 and to data cache 216 of processor 210. Instruction cache 214 outputs instructions to sequencer unit 218. In response to such instructions from instruction cache 214, sequencer unit 218 selectively outputs instructions to other execution circuitry of processor 210. In addition to sequencer unit 218, in the preferred embodiment, the execution circuitry of processor 210 includes multiple execution units, namely a branch unit 220, a fixed-point unit A (“FXUA”) 222, a fixed-point unit B (“FXUB”) 224, a complex fixed-point unit (“CFXU”) 226, a load/store unit (“LSU”) 228, and a floating-point unit (“FPU”) 230. FXUA 222, FXUB 224, CFXU 226, and LSU 228 input their source operand information from general-purpose architectural registers (“GPRs”) 232 and fixed-point rename buffers 234. Moreover, FXUA 222 and FXUB 224 input a “carry bit” from a carry bit (“CA”) register 239. FXUA 222, FXUB 224, CFXU 226, and LSU 228 output results (destination operand information) of their operations for storage at selected entries in fixed-point rename buffers 234. Also, CFXU 226 inputs and outputs source operand information and destination operand information to and from special-purpose register processing unit (“SPR unit”) 237. FPU 230 inputs its source operand information from floating-point architectural registers (“FPRs”) 236 and floating-point rename buffers 238. FPU 230 outputs results (destination operand information) of its operation for storage at selected entries in floating-point rename buffers 238. In response to a Load instruction, LSU 228 inputs information from data cache 216 and copies such information to selected ones of rename buffers 234 and 238. If such information is not stored in data cache 216, then data cache 216 inputs (through BIU 212 and system bus 211) such information from a system memory 239 connected to system bus 211. Moreover, data cache 216 is able to output (through BIU 212 and system bus 211) information from data cache 216 to system memory 239 connected to system bus 211. In response to a Store instruction, LSU 228 inputs information from a selected one of GPRs 232 and FPRs 236 and copies such information to data cache 216. Sequencer unit 218 inputs and outputs information to and from GPRs 232 and FPRs 236. From sequencer unit 218, branch unit 220 inputs instructions and signals indicating a present state of processor 210. In response to such instructions and signals, branch unit 220 outputs (to sequencer unit 218) signals indicating suitable memory addresses storing a sequence of instructions for execution by processor 210. In response to such signals from branch unit 220, sequencer unit 218 inputs the indicated sequence of instructions from instruction cache 214. If one or more of the sequence of instructions is not stored in instruction cache 214, then instruction cache 214 inputs (through BIU 212 and system bus 211) such instructions from system memory 239 connected to system bus 211. In response to the instructions input from instruction cache 214, sequencer unit 218 selectively dispatches the instructions to selected ones of execution units 220, 222, 224, 226, 228, and 230. Each execution unit executes one or more instructions of a particular class of instructions. For example, FXUA 222 and FXUB 224 execute a first class of fixed-point mathematical operations on source operands, such as addition, subtraction, ANDing, ORing and XORing. CFXU 226 executes a second class of fixed-point operations on source operands, such as fixed-point multiplication and division. FPU 230 executes floating-point operations on source operands, such as floating-point multiplication and division. As information is stored at a selected one of rename buffers 234, such information is associated with a storage location (e.g. one of GPRs 232 or carry bit (CA) register 242) as specified by the instruction for which the selected rename buffer is allocated. Information stored at a selected one of rename buffers 234 is copied to its associated one of GPRs 232 (or CA register 242) in response to signals from sequencer unit 218. Sequencer unit 218 directs such copying of information stored at a selected one of rename buffers 234 in response to “completing” the instruction that generated the information. Such copying is called “writeback.” As information is stored at a selected one of rename buffers 238, such information is associated with one of FPRs 236. Information stored at a selected one of rename buffers 238 is copied to its associated one of FPRs 236 in response to signals from sequencer unit 218. Sequencer unit 218 directs such copying of information stored at a selected one of rename buffers 238 in response to “completing” the instruction that generated the information. Processor 210 achieves high performance by processing multiple instructions simultaneously at various ones of execution units 220, 222, 224, 226, 228, and 230. Accordingly, each instruction is processed as a sequence of stages, each being executable in parallel with stages of other instructions. Such a technique is called “pipelining.” In a significant aspect of the illustrative embodiment, an instruction is normally processed as six stages, namely fetch, decode, dispatch, execute, completion, and writeback. In the fetch stage, sequencer unit 218 selectively inputs (from instruction cache 214) one or more instructions from one or more memory addresses storing the sequence of instructions discussed further hereinabove in connection with branch unit 220, and sequencer unit 218. In the decode stage, sequencer unit 218 decodes up to four fetched instructions. In the dispatch stage, sequencer unit 218 selectively dispatches up to four decoded instructions to selected (in response to the decoding in the decode stage) ones of execution units 220, 222, 224, 226, 228, and 230 after reserving rename buffer entries for the dispatched instructions' results (destination operand information). In the dispatch stage, operand information is supplied to the selected execution units for dispatched instructions. Processor 210 dispatches instructions in order of their programmed sequence. In the execute stage, execution units execute their dispatched instructions and output results (destination operand information) of their operations for storage at selected entries in rename buffers 234 and rename buffers 238 as discussed further hereinabove. In this manner, processor 210 is able to execute instructions out-of-order relative to their programmed sequence. In the completion stage, sequencer unit 218 indicates an instruction is “complete.” Processor 210 “completes” instructions in order of their programmed sequence. In the writeback stage, sequencer 218 directs the copying of information from rename buffers 234 and 238 to GPRs 232 and FPRs 236, respectively. Sequencer unit 218 directs such copying of information stored at a selected rename buffer. Likewise, in the writeback stage of a particular instruction, processor 210 updates its architectural states in response to the particular instruction. Processor 210 processes the respective “writeback” stages of instructions in order of their programmed sequence. Processor 210 advantageously merges an instruction's completion stage and writeback stage in specified situations. In the illustrative embodiment, each instruction requires one machine cycle to complete each of the stages of instruction processing. Nevertheless, some instructions (e.g., complex fixed-point instructions executed by CFXU 226) may require more than one cycle. Accordingly, a variable delay may occur between a particular instruction's execution and completion stages in response to the variation in time required for completion of preceding instructions. Completion buffer 248 is provided within sequencer 218 to track the completion of the multiple instructions which are being executed within the execution units. Upon an indication that an instruction or a group of instructions have been completed successfully, in an application specified sequential order, completion buffer 248 may be utilized to initiate the transfer of the results of those completed instructions to the associated general-purpose registers. In addition, processor 210 also includes performance monitor unit 240, which is connected to instruction cache 214 as well as other units in processor 210. Operation of processor 210 can be monitored utilizing performance monitor unit 240, which in this illustrative embodiment is a software-accessible mechanism capable of providing detailed information descriptive of the utilization of instruction execution resources and storage control. Although not illustrated in FIG. 2, performance monitor unit 240 is coupled to each functional unit of processor 210 to permit the monitoring of all aspects of the operation of processor 210, including, for example, reconstructing the relationship between events, identifying false triggering, identifying performance bottlenecks, monitoring pipeline stalls, monitoring idle processor cycles, determining dispatch efficiency, determining branch efficiency, determining the performance penalty of misaligned data accesses, identifying the frequency of execution of serialization instructions, identifying inhibited interrupts, and determining performance efficiency. The events of interest also may include, for example, time for instruction decode, execution of instructions, branch events, cache misses, and cache hits. Performance monitor unit 240 includes an implementation-dependent number (e.g., 2-8) of counters 241-242, labeled PMC1 and PMC2, which are utilized to count occurrences of selected events. Performance monitor unit 240 further includes at least one monitor mode control register (MMCR). In this example, two control registers, MMCRs 243 and 244 are present that specify the function of counters 241-242. Counters 241-242 and MMCRs 243-244 are preferably implemented as SPRs that are accessible for read or write via MFSPR (move from SPR) and MTSPR (move to SPR) instructions executable by CFXU 226. However, in one alternative embodiment, counters 241-242 and MMCRs 243-244 may be implemented simply as addresses in I/O space. In another alternative embodiment, the control registers and counters may be accessed indirectly via an index register. This embodiment is implemented in the IA-64 architecture in processors from Intel Corporation. Counters 241-242 may also be used to collect branch statistics per instruction when a program is executed. As described above, the present invention provides a method, apparatus, and computer instructions for local program code reorganization using branch count per instruction hardware. Program code reorganization may include reorganization of a single instruction or a set of instructions within a program, also known as a block of code. Instructions within a block of code may be contiguous or non-contiguous. The present invention provides hardware counter, such as counters 241 and 242 in FIG. 2, to count the number of times a branch is taken when a branch instruction is executed. In a preferred embodiment, the present invention allows a program or application to autonomically determine whether program code should be reorganized at run time by examining the branch count per instruction statistics provided by hardware counters. If code is to be reorganized, the performance monitoring program can use various techniques to halt execution of the instructions and then reorganizes the code by swapping instructions. Instruction is halted, for example, by causing a branch to branch to itself until modification of the code is complete, in order to ensure that the processor has stopped executing the code that is to be modified. When the relevant code has been modified and can be safely executed, the branch to self is removed and normal execution resumes. This mechanism allows a program to interrupt a normal execution and reorganize program code at run time. Turning to FIG. 3A, an exemplary diagram illustrating example branch statistic fields is depicted in accordance with a preferred embodiment of the present invention. In this illustrative example, there are three branch statistic fields, shown as branch field 302, branch prediction field 304, and branch count field 306 associated with a branch instruction. These branch statistics fields may be stored in a separate area of storage, such as performance instrumentation shadow cache. Performance instrumentation shadow cache may be implemented using any storage device, such as, for example, a system memory, a flash memory, a cache, or a disk. Branch field 302 indicates whether a branch is taken or not last time the branch instruction is executed. Branch prediction field 304 indicates the branch prediction made based on the branch count. There may be three values associated with the branch prediction field. A value of “00” indicates that no previous data is collected for the branch instruction. A value of “01” indicates a branch is predicted to be taken for the branch instruction, and a value of “02” indicates a branch is predicted to be not taken for the branch instruction. Branch prediction is normally performed before the branch is executed. Branch count field 306 indicates the number of times a branch is taken when the branch instruction is executed. Hardware counters increment or decrement this field based on whether a branch is taken or not when the branch instruction is executed. With reference to FIG. 3B, an exemplary diagram illustrating an example branch instruction is depicted in accordance with a preferred embodiment of the present invention. As depicted in FIG. 3B, branch instruction 310 is associated with two different meta data, meta data 312 and redirection address field 314. Meta data 312 represents the branch statistics fields as described in FIG. 3A, which is associated with branch instruction 310. Redirection address field 314 indicates that meta data is associated with branch instruction 310. With reference now to FIG. 4, an exemplary diagram illustrating an example meta data is depicted in accordance with a preferred embodiment of the present invention. In this illustrative example, meta data 402 may be stored in a dedicated memory location where it is accessible to the processor. Meta data 402 includes two pointers. One pointer points to the starting address of the reorganized code block 404. Another pointer points to the address of the instruction following the branch instructions in the original code 406. Pointer 404 is examined by the processor when a branch instruction associated with meta data, such as redirection address field 314 in FIG. 3B, is executed. Pointer 506 is examined by the processor when execution of the reorganized instruction is complete. In a preferred embodiment, the present invention allows a program to swap the location of the “then”, and “else” statements of an “if/then/else” statement within the program at run time based on the branch count per instruction statistics provided by hardware counters. An “if” statement specifies a condition that is examined when a branch instruction is executed. A “then” statement is an instruction that is executed when the “if” condition is satisfied. An “else” statement is an instruction that is executed when the “if” condition is not satisfied. Typically, an “else” statement follows the branch instruction in the normal execution sequence. For example, if the program determines that code should be reorganized at run time, the program may swap the location of “then” with the “else” statements, in order to allow more instructions to be executed contiguously before a branch is taken. Such swapping of then/else statements also requires modification of the condition. For example, in a simple case with a single condition “Value1 greater than 0,” the “then” statement would execute if Value1 is greater than zero, and the “else” statement would execute if Value1 is not greater than zero. Hence, swapping the “then” and “else” statements would also require that the condition “Value1 greater than 0” be modified to “Value1 less than or equal to 0.” In this way, the “then” statement will be executed under the same conditions as prior to code modification, and likewise with the “else” statement. Turning next to FIG. 5, an exemplary diagram illustrating program code reorganization by swapping “then” and “else” statements at run time is depicted in accordance with a preferred embodiment of the present invention. In this illustrative example, program 502 examines “if” condition 504 to check if the value in register R1 is not equal to zero. If “if” condition 504 is satisfied, a comparison is made by cmp instruction 506 to compare the value of register R1 and 0. If the value of register R1 is equal to 0, jmpe instruction 508 jumps to code block label 1 510. Code block label 1 510, which is the “else” statements, includes instructions 2, 3, 4, and 5. If the value of register R1 is not equal to 0, instruction 1 512, which is the “then” statement, is executed. Regardless of whether the “then” or the “else” statements are executed, code block label 2 516 is executed. Code block label 2 516 includes instructions 6, 7, 8, 9, 10 and return. Code block level 2 516 is common to either condition. By examining the branch count per instruction statistics provided by the hardware counters of the present invention, such as branch field 302 and branch prediction field 304 derived from the branch count field 306 as described in FIG. 3, program 502 may notice that code block label 1 510 is executed in multiple executions, which makes code block label 1 510 a “hot spot”. Thus, program 502 may reorganize the location of code block label 1 510 instructions at run time and the reorganized program is shown as program 520 in FIG. 5. Program 520 includes the same “if” condition 522 and cmp instruction 524. However, the condition of jmpe instruction 508 is modified to become a jmpne instruction 526. Jmpne instruction 526 jumps to code block label 2 528 only if the value of register R1 is not equal to 0. Instructions 2, 3, 4, and 5 530 that are originally located in code block label 1 510 are now relocated to be executed after jumpne instruction 526 to allow more contiguous code to be executed in sequence. Code block level 2 516 that is common to either condition is also relocated to code block label 1 532, which is executed after instructions 2, 3, 4 and 5 530 contiguously. Notice that the “else” condition 540 in program 502 is no longer required, since modifying the condition of jmpe statement 508 (jump if equal) to jmpne statement 526 (jump if not equal) in program 520 and relocating instructions 2, 3, 4 and 5 530 to be executed after jmpne instruction 526 allows “else” statements 530 to be executed right after the comparison is made. Thus, by swapping the locations of “then” statements 512 and “else” statements 510 and modifying the condition of jmpe statement 508, program 520 allows more instructions to be executed contiguously because “else” instructions 530 are now located closer to “if” condition 522. Turning next to FIG. 6, a flowchart process outlining an exemplary process for local program code reorganization using branch count per instruction hardware at run time is depicted in accordance with a preferred embodiment of the present invention. In this example illustration, the process begins when a CPU executes program instructions in execution sequence (step 602). The CPU then looks ahead and sees a branch instruction (step 604). Next, the program analyzes branch count per instruction statistics provided by the hardware counters (step 606) by examining the branch count field associated with the instruction. Based on the number of times a branch is taken, a determination is made by the program whether or not to reorganize code (step 608). If the program determines not to reorganize code, the processor continues to execute normal program instructions following the normal execution sequence (step 610), the process terminating thereafter. If the program determines to reorganize code, the program notifies the processor to halt execution of instructions (step 612) and swap the locations of the “then” and “else” statements such that more instructions are executed contiguously (step 614). Note that this step preferably includes modifying the condition of the “if” statement as well, such that the “then” instruction occurs under the same circumstances as before modification, as well as the “else” statement, as described above. Once the reorganization is complete, the program notifies the processor to restart execution of instructions (step 616) and the processor continues to execute normal program instructions following the normal execution sequence (step 610), the process terminating thereafter. Thus, the present invention provides branch count per instruction hardware to count the number of times a branch is taken. Using branch count per instruction statistics generated by the hardware counters, the program may determine whether or not to reorganize code locally at run time. A program may autonomically reorganize code by swapping the branch instruction with other instructions to optimize program performance. In an alternative embodiment, a program may swap the locations of the “then” and “else” statements (as well as changing the condition) to allow more instructions to be executed contiguously before taking a branch. Thus, the number of branches taken is minimized without modifying underlying program code. It is important to note that while the present invention has been described in the context of a fully functioning data processing system, those of ordinary skill in the art will appreciate that the processes of the present invention are capable of being distributed in the form of a computer readable medium of instructions and a variety of forms and that the present invention applies equally regardless of the particular type of signal bearing media actually used to carry out the distribution. Examples of computer readable media include recordable-type media, such as a floppy disk, a hard disk drive, a RAM, CD-ROMs, DVD-ROMs, and transmission-type media, such as digital and analog communications links, wired or wireless communications links using transmission forms, such as, for example, radio frequency and light wave transmissions. The computer readable media may take the form of coded formats that are decoded for actual use in a particular data processing system. The description of the present invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to best explain the principles of the invention, the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Technical Field The present invention relates generally to an improved data processing system and, in particular, to a method and system for improving performance of the processor in a data processing system. Still more particularly, the present invention relates to a method, apparatus, and computer instructions for local code reorganization using branch count per instruction hardware. 2. Description of Related Art In a computer system, branch prediction is a technique used to guess whether a conditional branch will be taken or not. If it is predicted that a conditional branch will be taken, the processor will prefetch code for the branch instruction from the appropriate location. A speculative execution is performed to take advantage of branch prediction by executing the instruction before the processor is certain that they are in the correct execution path. For example, if a branch is taken more than 90 percent of the time, it is predicted to be taken and the processor will prefetch the code prior to reaching the branch instruction. A branch instruction may be conditional or unconditional. A conditional branch instruction causes an instruction to branch or jump to another location of code if a specified condition is satisfied. If the condition is not satisfied, the next instruction in sequential order is fetched and executed. A special fetch/decode unit in a processor uses a branch prediction algorithm to predict the direction and outcome of the instructions being executed through multiple levels of branches, calls, and returns. Branch prediction enables the processor to keep the instruction pipeline full while running at a high rate of speed. In conventional computer systems, branch prediction is based on branch prediction software that uses branch statistics and other data to minimize stalls caused by delays in fetching instructions that branch to nonlinear memory locations. In some cases, the code of a program can be locally reorganized to improve performance. Such code reorganization is typically based on software generated statistics to determine whether local code reorganization is advantageous. However, such software generated statistics require use of resources that may in some cases be better allocated to other tasks, while hardware resources that may be present go unused, resulting in an inefficient use of overall resources. Therefore, it would be advantageous to have an improved method, apparatus, and computer instructions for providing branch count per instruction statistics that allow a program to autonomically perform local code reorganization, so that processor performance may be optimized. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention provides a method, apparatus, and computer instructions for local program code reorganization at run time using branch count per instruction hardware. In a preferred embodiment, the mechanism of the present invention allows a program to analyze branch count per instruction statistics generated using hardware counters. The branch count per instruction statistics identify the number of times a branch is actually taken when a branch instruction is executed. Based on the branch count per instruction statistics, the program autonomically determines whether the code requires reorganization in order to optimize processor performance. The program may reorganize the code by swapping location of an “if/then/else” statement locally so that more instructions may be executed contiguously prior to taking the branch. This run time code reorganization minimizes the number of branches taken without modifying the underlying application code. | 20040114 | 20071030 | 20050714 | 73743.0 | 0 | RUTTEN, JAMES D | AUTONOMIC METHOD AND APPARATUS FOR LOCAL PROGRAM CODE REORGANIZATION USING BRANCH COUNT PER INSTRUCTION HARDWARE | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,757,192 | ACCEPTED | Method and apparatus for providing pre and post handlers for recording events | A method, apparatus, and computer instructions for providing pre and post handlers to log trace records before entering or after exiting the interrupt handler. A trace record includes a ‘from’ address where the interrupt occurs or where the branch instruction is executed or a ‘to’ address for the branch to case and counts of selected performance monitoring events. A timestamp may be associated with each event. In one embodiment, the pre and post handler is used with trap on branch to log trace records prior to and immediate after taking a branch. In another embodiment, a pre handler is enabled to log trace records that occur prior to executing interrupt service routines. A post handler is enabled to log trace records that occur after the interrupt service routines is executed and prior to returning to normal execution. Resulting low-level performance trace data may be collected by the user at a later time for more structured performance analysis. | 1. A method of processing performance information in a data processing system, comprising the steps of: receiving an interrupt signal at an interrupt unit of a processor of the data processing system; determining if at least one of a pre handler routine and a post handler routine are enabled for an interrupt; invoking the pre handler routine to record events at a first instant if the pre routine is enabled; invoking an interrupt handler routine; and invoking the post handler routine to record events at a second instant if the post handler routine is enabled. 2. The method of claim 1, wherein recording events includes recording a plurality of counts. 3. The method of claim 1, wherein recording events includes recording a timestamp. 4. The method of claim 2, wherein the count represents the number of times an event occurs. 5. The method of claim 4, wherein the event is selected from the group consisting of cache misses and number of instructions executed. 6. The method of claim 1, wherein the first and second instants are associated with first and second timestamps, respectively. 7. The method of claim 1, further comprising a plurality of pre handler routines and a plurality of post handler routines, wherein each pre handler routine and each post handler routine records a different event on the occurrence of an interrupt. 8. The method of claim 1, wherein recording events includes accumulating a total value of counts. 9. The method of claim 8, wherein the total value of counts is accumulated by adding counts of events recorded. 10. The method of claim 8, wherein the total value of counts is displayed in a performance analysis tool. 11. The method of claim 2, wherein the count is not updated when the pre or post handler routine is invoked. 12. A method of executing instructions in a data processing system, comprising the steps of: receiving an interrupt signal at an interrupt unit of a processor of the data processing system; determining if at least one of a pre handler routine and a post handler routine are enabled for an interrupt; invoking the pre handler routine to log a trace record at a first instant if the pre routine is enabled; invoking an interrupt handler routine; invoking the post handler routine to log a trace record at a second instant if the post handler routine is enabled. 13. The method of claim 12, wherein the trace record includes a from address of an instruction indicating where the interrupt occurs. 14. The method of claim 12, wherein the trace record includes a plurality of counts. 15. The method of claim 14, wherein the count represents the number of times an event occurs. 16. The method of claim 15, wherein the event is selected from the group consisting of cache misses and clock cycles. 17. The method of claim 12, wherein the trace record includes a timestamp. 18. The method of claim 12, further comprising a plurality of pre handler routines and a plurality of post handler routines, wherein each pre handler routine and each post handler routine logs a different event on the occurrence of an interrupt. 19. The method of claim 12, wherein the first and second instants are associated with first and second timestamps, respectively. 20. The method of claim 12, wherein the pre handler routine or the post handler routine monitors a count of recorded events to determine if an overflow occurred. 21. The method of claim 20, wherein the pre handler routine or the post handler routine handles the overflow by reading and resetting the count. 22. A data processing system, comprising: an interrupt unit for receiving interrupt signals; a pre handler routine and a post handler routine; wherein responsive to receiving an interrupt signal for an interrupt at the interrupt unit, the pre handler routine logs a trace record at a first instant; and wherein responsive to completion of the interrupt, the post handler routine logs a trace record at a second instant. 23. The system of claim 22, wherein the trace record includes a from address of an instruction indicating where the interrupt occurs. 24. The system of claim 22, wherein the trace record includes a plurality of counts. 25. The system of claim 24, wherein the count represents the number of times an event occurs. 26. The system of claim 25, wherein the event is selected from the group consisting of cache misses and clock cycles. 27. The system of claim 22, wherein the trace record includes a timestamp. 28. The system of claim 22, further comprising a plurality of pre handler routines and a plurality of post handler routines, wherein each pre handler routine and each post handler routine logs a different event on the occurrence of an interrupt. 29. The system of claim 22, wherein the first and second instants are associated with first and second time stamps, respectively. 30. The system of claim 24, wherein the count is not updated when the pre or post handler routine is invoked. 31. The system of claim 22, wherein the pre handler routine or the post handler routine monitors a count of recorded events to determine if an overflow occurred. 32. The system of claim 31, wherein the pre handler routine or the post handler routine handles the overflow by reading and resetting the count. 33. A computer program product in a computer readable medium, comprising: first instructions for receiving an interrupt signal at an interrupt unit of a processor of the data processing system; second instructions for determining if at least one of a pre handler routine and a post handler routine are enabled for an interrupt; third instructions for invoking the pre handler routine to log a trace record at a first instant if the pre routine is enabled; fourth instructions for invoking an interrupt handler routine; fifth instructions for invoking the post handler routine to log a trace record at a second instant if the post handler routine is enabled. 34. The computer program product of claim 33, wherein the trace record includes a from address of an instruction indicating where the interrupt occurs. 35. The computer program product of claim 33, wherein the trace record includes a plurality of counts. 36. The computer program product of claim 35, wherein the count represents the number of times an event occurs. 37. The computer program product of claim 36, wherein the event is selected from the group consisting of cache misses and clock cycles. 38. The computer program product of claim 33, wherein the trace record includes a timestamp. 39. The computer program product of claim 33, further comprising a plurality of pre handler routines and a plurality of post handler routines, wherein each pre handler routine and each post handler routine logs a different event on the occurrence of an interrupt. 40. The computer program product of claim 33, wherein the first and second instants are associated with first and second timestamps in the trace record, respectively. 41. The computer program product of claim 33, wherein the pre handler routine or the post handler routine monitors a count of recorded events to determine if an overflow occurred. 42. The computer program product of claim 35, wherein the count is not updated when the pre or post handler is invoked. 43. The computer program product of claim 41, wherein the pre handler routine or the post handler routine handles the overflow by reading and resetting the count. 44. A method of executing branch instructions in a data processing system, comprising the steps of: executing a branch instruction of a program; receiving a signal at an interrupt unit of a processor of the data processing system in response to executing a trap, wherein the trap is executed in response to executing the branch instruction of the program. invoking a pre handler routine to log a trace record at a first instant in response to receiving the signal; invoking the post handler routine to log a trace record at a second instant when the execution of the branch instruction of a program is complete. 45. The method of claim 44, wherein the trace record includes a from address indicating an address of the branch instruction. 46. The method of claim 44, wherein the trace record includes a to address indicating an address of branch to instruction. 47. The method of claim 44, wherein the trace record includes a plurality of counts. 48. The method of claim 47, wherein the count represents the number of times an event occurs. 49. The method of claim 44, wherein the trace record includes a timestamp. 50. The method of claim 48, wherein the event is selected from the group consisting of cache misses and clock cycles. 51. The method of claim 44, further comprising a plurality of pre handler routines and a plurality of post handler routines, wherein each pre handler routine and each post handler routine logs a different event. 52. The method of claim 44, wherein the first and second instants are associated with first and second timestamps in the trace record, respectively. 53. The method of claim 47, wherein the count is not updated when the pre and post handler routine is invoked. | CROSS REFERENCE TO RELATED APPLICATIONS The present invention is related to the following applications entitled “Method and Apparatus for Counting Instruction Execution and Data Accesses”, Ser. No. ______, attorney docket no. AUS920030477US1, filed on Sep. 30, 2003; “Method and Apparatus for Selectively Counting Instructions and Data Accesses”, Ser. No. ______, attorney docket no. AUS920030478US1, filed on Sep. 30, 2003; “Method and Apparatus for Generating Interrupts Upon Execution of Marked Instructions and Upon Access to Marked Memory Locations”, Ser. No. ______, attorney docket no. AUS920030479US1, filed on Sep. 30, 2003; “Method and Apparatus for Counting Data Accesses and Instruction Executions that Exceed a Threshold”, Ser. No. ______, attorney docket no. AUS920030480US1, filed on Sep. 30, 2003; “Method and Apparatus for Counting Execution of Specific Instructions and Accesses to Specific Data Locations”, Ser. No. ______, attorney docket no. AUS920030481US1, filed on Sep. 30, 2003; “Method and Apparatus for Debug Support for Individual Instructions and Memory Locations”, Ser. No. ______, attorney docket no. AUS920030482US1, filed on Sep. 30, 2003; “Method and Apparatus to Autonomically Select Instructions for Selective Counting”, Ser. No. ______, attorney docket no. AUS920030483US1, filed on Sep. 30, 2003; “Method and Apparatus to Autonomically Count Instruction Execution for Applications”, Ser. No. ______, attorney docket no. AUS920030484US1, filed on Sep. 30, 2003; “Method and Apparatus to Autonomically Take an Exception on Specified Instructions”, Ser. No. ______, attorney docket no. AUS920030485US1, filed on Sep. 30, 2003; “Method and Apparatus to Autonomically Profile Applications”, Ser. No. ______, attorney docket no. AUS920030486US1, filed on Sep. 30, 2003; “Method and Apparatus for Counting Instruction and Memory Location Ranges”, Ser. No. ______, attorney docket no. AUS920030487US1, filed on Sep. 30, 2003; “Method and Apparatus for Qualifying Collection of Performance Monitoring Events by Types of Interrupt When Interrupt Occurs”, Ser. No. ______, attorney docket no. AUS920030540US1, filed on ______; and “Method and Apparatus for Counting Interrupts by Type”, Ser. No. ______, attorney docket no. AUS920030541US1, filed on ______. All of the above related applications are assigned to the same assignee, and incorporated herein by reference. BACKGROUND OF THE INVENTION 1. Technical Field The present invention relates generally to an improved data processing system and, in particular, to a method and system for monitoring performance of the processor in a data processing system when an interrupt occurs. Still more particularly, the present invention relates to a method, apparatus, and computer instructions for providing pre handlers and post handlers to record events. 2. Description of Related Art A typical data processing system utilizes processors to execute a set of instructions in order to perform a certain task, such as reading a specific character from the main memory. However, as the number of tasks required to be executed by the processor increases, the efficiency of the processor's access patterns to memory and the characteristics of such access become important factors for engineers who want to optimize the system. Currently, the prior art contains mechanisms that can count occurrences of software-selectable events, such as, for example, cache misses, instructions executed, I/O data transfer request, and the time a given process may take to execute within a data processing system. One such mechanism is a performance monitor. A performance monitor monitors selected characteristics for system analysis by determining a machine's state at a particular time. This analysis provides information of how the processor is used when instructions are executed and its interaction with the main memory when data is stored. This analysis may also be used to determine if application code changes, such as a relocation of branch instructions and memory access, to further optimize the performance of a system are necessary. In addition, the performance monitor may provide the amount of time that has passed between events in a processing system. The performance monitor counts events that may be used by engineers to analyze system performance. Moreover, data regarding how the processor accesses the data processing system's level 1 and level 2 cache, and main memory may be gathered by the performance monitor in order to identify performance bottlenecks that are specific to a hardware or software environment. In addition to the performance monitor described above, an interrupt processing unit may be used to record events such as, for example, instruction execution, branch events, or system events when an interrupt occurs. An interrupt occurs when a device, such as a mouse or keyboard, raises an interrupt signal to notify the processor that an event has occurred. When the processor accepts an interrupt request, the processor completes its current instruction and passes the control to an interrupt handler. The interrupt handler executes an interrupt service routine that is associated with the interrupt. An interrupt may also be caused by a specific machine language operation code, for example Motorola 68000's TRAP, a product from Motorola, Inc. In this case, an unexpected software condition such as divide by zero causes the processor to store the current state, store identifying information about the particular interrupt and pass control to an interrupt handler that handles this unexpected software condition. However, the performance monitor above must modify the application program at run time in order to record precise performance trace data, such as the number of instructions executed during interrupt processing. Therefore, it would be advantageous to have an improved method, apparatus, and computer instructions for providing pre and post handlers to record precise performance data for events occurring before entering and immediately after exiting an interrupt handler without modifying underlying application program. SUMMARY OF THE INVENTION The present invention provides a method, apparatus, and computer instructions for providing pre and post handlers to record events when an interrupt occurs. The pre and post handlers allow logging of trace records along with timestamps associated with performance monitoring events to be recorded in order to provide the user with more fine-grained performance data. In a preferred embodiment, the mechanism of the present invention provides pre and post handlers to record the occurrence of performance monitoring events when a branch instruction is executed. The pre and post handlers are used with a “trap on branch”, i.e. a trap, or interrupt, being processed when a branch instruction is executed, to produce an instruction trace which includes the ‘from’ address of where the branch is taken and may include the ‘to’ address of where the branch branches to. It should be clear that information could be compressed in various ways to minimize the amount of information to be recorded. The pre and post handlers record performance monitoring events occurring prior to and immediately after taking the branch. In an alternative embodiment, before the processor fetches instructions from the interrupt handler when an interrupt occurs, the mechanism of the present invention allows the pre handler to log trace records prior to entering the interrupt handler. The events recorded provide the state of the system when entering an interrupt handler. When the interrupt handler completes the interrupt service routine, the mechanism of the present inventions allows the post handler to record events and low level information, such as the number of instructions executed for an interrupt, before returning to normal execution. This low-level information may provide the state of the system when exiting an interrupt. These and other features and advantages will be discussed in, or will become apparent to those of ordinary skill in the art in view of, the following detailed description of the preferred embodiments. BRIEF DESCRIPTION OF THE DRAWINGS The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: FIG. 1 is an exemplary block diagram of a data processing system in which the present invention may be implemented; FIG. 2 is an exemplary block diagram of a processor system for processing information in accordance with a preferred embodiment of the present invention; FIG. 3 is an exemplary diagram illustrating components for recording events of an interrupt using pre and post handler in accordance with a preferred embodiment of the present invention; FIG. 4 is an exemplary diagram illustrating an example interrupt description table (IDT) in accordance with a preferred embodiment of the present invention; FIG. 5 is a flowchart outlining an exemplary process for recording events of an interrupt using pre and post handlers in accordance with a preferred embodiment of the present invention; and FIG. 6 is a flowchart outlining an exemplary process for logging trace records when a branch instruction is executed with trap on branch using pre and post handlers in accordance with a preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The mechanism of the present invention provides pre and post handlers to log trace records, including the ‘from’ address of where an interrupt occurs or where a branch instruction is executed. The pre and post handlers record events, such as performance monitoring events, prior to entering and after exiting an interrupt handler or taking a branch. By logging these trace records, engineers may identify values of performance monitoring events at a particular instant in time. These records may assist engineers in isolating events that occur during normal execution of the system from events that occur in the system when an interrupt is handled or when a branch is taken. The present invention may be implemented in a computer system. The computer system may be a stand-alone computing device, a client or server computing device in a client-server environment that is interconnected over a network, or the like. FIG. 1 provides an exemplary diagram of a computing device in which aspects of the present invention may be implemented. FIG. 1 is only exemplary and no limitation on the structure or organization of the computing devices on which the present invention may be implemented is asserted or implied by the depicted example. With reference now to FIG. 1, an exemplary block diagram of a data processing system is shown in which the present invention may be implemented. Client 100 is an example of a computer, in which code or instructions implementing the processes of the present invention may be located. Client 100 employs a peripheral component interconnect (PCI) local bus architecture. Although the depicted example employs a PCI bus, other bus architectures such as Accelerated Graphics Port (AGP) and Industry Standard Architecture (ISA) may be used. Processor 102 and main memory 104 are connected to PCI local bus 106 through PCI bridge 108. PCI bridge 108 also may include an integrated memory controller and cache memory for processor 102. Additional connections to PCI local bus 106 may be made through direct component interconnection or through add-in boards. In the depicted example, local area network (LAN) adapter 110, small computer system interface SCSI host bus adapter 112, and expansion bus interface 114 are connected to PCI local bus 106 by direct component connection. In contrast, audio adapter 116, graphics adapter 118, and audio/video adapter 119 are connected to PCI local bus 106 by add-in boards inserted into expansion slots. Expansion bus interface 114 provides a connection for a keyboard and mouse adapter 120, modem 122, and additional memory 124. SCSI host bus adapter 112 provides a connection for hard disk drive 126, tape drive 128, and CD-ROM drive 130. Typical PCI local bus implementations will support three or four PCI expansion slots or add-in connectors. An operating system runs on processor 102 and is used to coordinate and provide control of various components within data processing system 100 in FIG. 1. The operating system may be a commercially available operating system such as Windows XP, which is available from Microsoft Corporation. An object oriented programming system such as Java may run in conjunction with the operating system and provides calls to the operating system from Java programs or applications executing on client 100. “Java” is a trademark of Sun Microsystems, Inc. Instructions for the operating system, the object-oriented programming system, and applications or programs are located on storage devices, such as hard disk drive 126, and may be loaded into main memory 104 for execution by processor 102. Those of ordinary skill in the art will appreciate that the hardware in FIG. 1 may vary depending on the implementation. Other internal hardware or peripheral devices, such as flash read-only memory (ROM), equivalent nonvolatile memory, or optical disk drives and the like, may be used in addition to or in place of the hardware depicted in FIG. 1. Also, the processes of the present invention may be applied to a multiprocessor data processing system. For example, client 100, if optionally configured as a network computer, may not include SCSI host bus adapter 112, hard disk drive 126, tape drive 128, and CD-ROM 130. In that case, the computer, to be properly called a client computer, includes some type of network communication interface, such as LAN adapter 110, modem 122, or the like. As another example, client 100 may be a stand-alone system configured to be bootable without relying on some type of network communication interface, whether or not client 100 comprises some type of network communication interface. As a further example, client 100 may be a personal digital assistant (PDA), which is configured with ROM and/or flash ROM to provide non-volatile memory for storing operating system files and/or user-generated data. The depicted example in FIG. 1 and above-described examples are not meant to imply architectural limitations. The processes of the present invention are performed by processor 102 using computer implemented instructions, which may be located in a memory such as, for example, main memory 104, memory 124, or in one or more peripheral devices 126-130. Turning next to FIG. 2, an exemplary block diagram of a processor system for processing information is depicted in accordance with a preferred embodiment of the present invention. Processor 210 may be implemented as processor 102 in FIG. 1. In a preferred embodiment, processor 210 is a single integrated circuit superscalar microprocessor. Accordingly, as discussed further herein below, processor 210 includes various units, registers, buffers, memories, and other sections, all of which are formed by integrated circuitry. Also, in the preferred embodiment, processor 210 operates according to reduced instruction set computer (“RISC”) techniques. As shown in FIG. 2, system bus 211 is connected to a bus interface unit (“BIU”) 212 of processor 210. BIU 212 controls the transfer of information between processor 210 and system bus 211. BIU 212 is connected to an instruction cache 214 and to data cache 216 of processor 210. Instruction cache 214 outputs instructions to sequencer unit 218. In response to such instructions from instruction cache 214, sequencer unit 218 selectively outputs instructions to other execution circuitry of processor 210. In addition to sequencer unit 218, in the preferred embodiment, the execution circuitry of processor 210 includes multiple execution units, namely a branch unit 220, a fixed-point unit A (“FXUA”) 222, a fixed-point unit B (“FXUB”) 224, a complex fixed-point unit (“CFXU”) 226, a load/store unit (“LSU”) 228, and a floating-point unit (“FPU”) 230. FXUA 222, FXUB 224, CFXU 226, and LSU 228 input their source operand information from general-purpose architectural registers (“GPRs”) 232 and fixed-point rename buffers 234. Moreover, FXUA 222 and FXUB 224 input a “carry bit” from a carry bit (“CA”) register 239. FXUA 222, FXUB 224, CFXU 226, and LSU 228 output results (destination operand information) of their operations for storage at selected entries in fixed-point rename buffers 234. Also, CFXU 226 inputs and outputs source operand information and destination operand information to and from special-purpose register processing unit (“SPR unit”) 237. FPU 230 inputs its source operand information from floating-point architectural registers (“FPRs”) 236 and floating-point rename buffers 238. FPU 230 outputs results (destination operand information) of its operation for storage at selected entries in floating-point rename buffers 238. In response to a Load instruction, LSU 228 inputs information from data cache 216 and copies such information to selected ones of rename buffers 234 and 238. If such information is not stored in data cache 216, then data cache 216 inputs (through BIU 212 and system bus 211) such information from a system memory 239 connected to system bus 211. Moreover, data cache 216 is able to output (through BIU 212 and system bus 211) information from data cache 216 to system memory 239 connected to system bus 211. In response to a Store instruction, LSU 228 inputs information from a selected one of GPRs 232 and FPRs 236 and copies such information to data cache 216. Sequencer unit 218 inputs and outputs information to and from GPRs 232 and FPRs 236. From sequencer unit 218, branch unit 220 inputs instructions and signals indicating a present state of processor 210. In response to such instructions and signals, branch unit 220 outputs (to sequencer unit 218) signals indicating suitable memory addresses storing a sequence of instructions for execution by processor 210. In response to such signals from branch unit 220, sequencer unit 218 inputs the indicated sequence of instructions from instruction cache 214. If one or more of the sequence of instructions is not stored in instruction cache 214, then instruction cache 214 inputs (through BIU 212 and system bus 211) such instructions from system memory 239 connected to system bus 211. In response to the instructions input from instruction cache 214, sequencer unit 218 selectively dispatches the instructions to selected ones of execution units 220, 222, 224, 226, 228, and 230. Each execution unit executes one or more instructions of a particular class of instructions. For example, FXUA 222 and FXUB 224 execute a first class of fixed-point mathematical operations on source operands, such as addition, subtraction, ANDing, ORing and XORing. CFXU 226 executes a second class of fixed-point operations on source operands, such as fixed-point multiplication and division. FPU 230 executes floating-point operations on source operands, such as floating-point multiplication and division. As information is stored at a selected one of rename buffers 234, such information is associated with a storage location (e.g. one of GPRs 232 or carry bit(CA) register 242) as specified by the instruction for which the selected rename buffer is allocated. Information stored at a selected one of rename buffers 234 is copied to its associated one of GPRs 232 (or CA register 242) in response to signals from sequencer unit 218. Sequencer unit 218 directs such copying of information stored at a selected one of rename buffers 234 in response to “completing” the instruction that generated the information. Such copying is called “writeback.” As information is stored at a selected one of rename buffers 238, such information is associated with one of FPRs 236. Information stored at a selected one of rename buffers 238 is copied to its associated one of FPRs 236 in response to signals from sequencer unit 218. Sequencer unit 218 directs such copying of information stored at a selected one of rename buffers 238 in response to “completing” the instruction that generated the information. Processor 210 achieves high performance by processing multiple instructions simultaneously at various ones of execution units 220, 222, 224, 226, 228, and 230. Accordingly, each instruction is processed as a sequence of stages, each being executable in parallel with stages of other instructions. Such a technique is called “pipelining.” In a significant aspect of the illustrative embodiment, an instruction is normally processed as six stages, namely fetch, decode, dispatch, execute, completion, and writeback. In the fetch stage, sequencer unit 218 selectively inputs (from instruction cache 214) one or more instructions from one or more memory addresses storing the sequence of instructions discussed further hereinabove in connection with branch unit 220, and sequencer unit 218. In the decode stage, sequencer unit 218 decodes up to four fetched instructions. In the dispatch stage, sequencer unit 218 selectively dispatches up to four decoded instructions to selected (in response to the decoding in the decode stage) ones of execution units 220, 222, 224, 226, 228, and 230 after reserving rename buffer entries for the dispatched instructions' results (destination operand information). In the dispatch stage, operand information is supplied to the selected execution units for dispatched instructions. Processor 210 dispatches instructions in order of their programmed sequence. In the execute stage, execution units execute their dispatched instructions and output results (destination operand information) of their operations for storage at selected entries in rename buffers 234 and rename buffers 238 as discussed further hereinabove. In this manner, processor 210 is able to execute instructions out-of-order relative to their programmed sequence. In the completion stage, sequencer unit 218 indicates an instruction is “complete.” Processor 210 “completes” instructions in order of their programmed sequence. In the writeback stage, sequencer 218 directs the copying of information from rename buffers 234 and 238 to GPRs 232 and FPRs 236, respectively. Sequencer unit 218 directs such copying of information stored at a selected rename buffer. Likewise, in the writeback stage of a particular instruction, processor 210 updates its architectural states in response to the particular instruction. Processor 210 processes the respective “writeback” stages of instructions in order of their programmed sequence. Processor 210 advantageously merges an instruction's completion stage and writeback stage in specified situations. In the illustrative embodiment, each instruction requires one machine cycle to complete each of the stages of instruction processing. Nevertheless, some instructions (e.g., complex fixed-point instructions executed by CFXU 226) may require more than one cycle. Accordingly, a variable delay may occur between a particular instruction's execution and completion stages in response to the variation in time required for completion of preceding instructions. Completion buffer 248 is provided within sequencer 218 to track the completion of the multiple instructions which are being executed within the execution units. Upon an indication that an instruction or a group of instructions have been completed successfully, in an application specified sequential order, completion buffer 248 may be utilized to initiate the transfer of the results of those completed instructions to the associated general-purpose registers. In addition, processor 210 also includes performance monitor unit 240, which is connected to instruction cache 214 as well as other units in processor 210. Operation of processor 210 can be monitored utilizing performance monitor unit 240, which in this illustrative embodiment is a software-accessible mechanism capable of providing detailed information descriptive of the utilization of instruction execution resources and storage control. Although not illustrated in FIG. 2, performance monitor unit 240 is coupled to each functional unit of processor 210 to permit the monitoring of all aspects of the operation of processor 210, including, for example, reconstructing the relationship between events, identifying false triggering, identifying performance bottlenecks, monitoring pipeline stalls, monitoring idle processor cycles, determining dispatch efficiency, determining branch efficiency, determining the performance penalty of misaligned data accesses, identifying the frequency of execution of serialization instructions, identifying inhibited interrupts, and determining performance efficiency. The events of interest also may include, for example, time for instruction decode, execution of instructions, branch events, cache misses, and cache hits. Performance monitor unit 240 includes an implementation-dependent number (e.g., 2-8) of counters 241-242, labeled PMC1 and PMC2, which are utilized to count occurrences of selected events. Performance monitor unit 240 further includes at least one monitor mode control register (MMCR). In this example, two control registers, MMCRs 243 and 244 are present that specify the function of counters 241-242. Counters 241-242 and MMCRs 243-244 are preferably implemented as SPRs that are accessible for read or write via MFSPR (move from SPR) and MTSPR (move to SPR) instructions executable by CFXU 226. However, in one alternative embodiment, counters 241-242 and MMCRs 243-244 may be implemented simply as addresses in I/O space. In another alternative embodiment, the control registers and counters may be accessed indirectly via an index register. This embodiment is implemented in the IA-64 architecture in processors from Intel Corporation. Additionally, processor 210 also includes interrupt unit 250, which is connected to instruction cache 214. Additionally, although not shown in FIG. 2, interrupt unit 250 is connected to other functional units within processor 210. Interrupt unit 250 may receive signals from other functional units and initiate an action, such as starting an error handling or trap process. In these examples, interrupt unit 250 is employed to generate interrupts and exceptions that may occur during execution of a program. The present invention provides a method, apparatus, and computer instructions for providing pre and post handlers to record events. The pre and post handlers may perform different operations to obtain different computer program execution metric information for use by a performance analysis tool in providing analysis of the computer program's performance during execution. The pre handler is intended to be used to obtain information about computer program execution metrics as they are prior to execution of interrupt handling routines. The post handler is intended to be used to obtain information about what occurs during the handling of an interrupt, i.e. during execution of the interrupt handling routines. A trap, i.e. a piece of code that executes when a particular condition has occurred, such as a when a particular interrupt or exception has been generated, etc also is referred to herein as a trap or an interrupt service routines. With the present invention, as part of handling this trap, the processor of the present invention calls a pre handler prior to calling the trap or interrupt handling routines. That is, when the trap instruction generates an interrupt, or otherwise attempts to transfer control to a trap handling routine, the processor redirects this call to a pre handler which may accumulate or otherwise obtain performance monitoring metric information from performance monitor mechanisms associated with the computer program. This information may then be stored for identifying the state of the execution of the computer program prior to the trap or interrupt handler having been executed. Similarly, when a trap occurs and the trap or interrupt handling routine has been executed, the post handler may be executed after execution of the trap or interrupt handling routine to obtain information about what occurred during execution of the trap or interrupt handling routine. For example, the post handler may add the number of instructions or cache misses that occurred in the interrupt handler itself to accumulate a total value that can be output to the performance analysis tool for use during performance analysis of the computer program. In order to perform different operations, the pre and post handlers process performance monitor metric information, hereafter referred to as “performance information”, using values of events that occurred and timestamps associated with the events. In addition, the pre and post handlers may log trace records. A trace record may include a ‘from’ address of the instruction where an event occurs as well as counts for a selected event, and a time stamp identifying when the trace record is being written. Events recorded may include performance monitoring events occurring before entering and after exiting an interrupt service routine. The pre and post handlers are instruction routines that log trace records or process information about the state of the machine. Trace records may also include information read from performance monitoring counters, such as counters 241-242 in FIG. 2, and timestamps associated for each event. Examples of performance monitoring events are the number of instructions executed, the number of cache misses, the number of table lookaside buffer (TLB) misses, etc. The pre and post handlers accumulate trace records for events that occur prior to and during the execution of the interrupt service routine, or trap/interrupt handling routine, by recording the values of performance monitor counters before executing the handler and recording the values of the performance monitor counters right after executing the handler. The performance monitor may be programmed to stop counting events while the pre and post handlers are being executed. The pre and post handlers of the present invention may be enabled or disabled. As a result, customized performance monitoring information may be obtainable by determining which pre and post handlers to enable or disable. In this way, a user may obtain performance information that is of particular interest to the problems of importance to that user. This permits a great deal of flexibility with regard to what performance monitoring information is compiled and analyzed by pre and post handlers. In addition, the pre and post handler routines may also be used with “trap on branch” instructions to produce a trace record. As touched upon above, a trap is a specialized piece of code in a program that occurs due to a particular condition in a running program. A “trap on branch”, otherwise referred to as a “branch trap”, is a trap that occurs if a branch is taken. If the branch is taken, then the trap on branch handler receives control. In a preferred embodiment of the present invention, one or more branches in the computer program being monitored are selected for monitoring. When one of these branch instructions selected for monitoring is executed, i.e. when the branch is taken, the processor sends a signal to the interrupt unit. Rather than fetching instructions from the normal trap handling routine, the interrupt unit notifies the processor to fetch instructions from the pre handler to log trace records prior to executing the trap handling routine and taking the branch, if the pre handler is enabled. A trace record may include a ‘from’ memory address, which is the memory address of the branch instruction when the branch is taken. In addition, the trace record may also include a ‘to’ memory address, which is the memory address of where to branch to. Associated with these addresses may be performance monitoring information that may be obtained from performance monitoring devices and data structures, e.g., counters 241-242. An example of performance monitoring information that may be obtained and associated with the ‘to’ and/or ‘from’ and from addresses is selected counts of performance monitoring events, such as the number of cache misses that have occurred. After the pre handler routine is executed, the normal trap service routine, or trap handler routine, is be executed. A post handler routine may also be associated with the trap that is placed in the program. This post handler routine is called after the normal trap service routine has finished executing and attempts to return control of the computer program to the normal code of the computer program. Upon completion of the normal trap service routine, and prior to returning to normal execution, the processor sends a signal to the interrupt unit indicating completion of the normal trap service routine. As a result, if the post handler is enabled, the interrupt unit notifies the processor to fetch instructions from the post handler in order to log trace records after taking the branch. Thus, the pre and post handlers allow the user to record low-level performance data prior to and immediately after execution of a trap/interrupt handling routine. One preferred application of this functionality is for the “trap on branch” conditions discussed above. Normally, when an interrupt occurs, such as when a page fault occurs during program execution, the processor stops the current execution and begins fetching instructions from the address of the entry point to the interrupt handler. An interrupt handler includes interrupt service routines that are fetched by the processor to handle an interrupt. The address of the entry point is stored in the interrupt descriptor table (IDT) which is a system table that associates each interrupt with a corresponding interrupt handler containing corresponding interrupt service routines. However, in one exemplary embodiment of the present invention, in response to the occurrence of an interrupt event that causes an interrupt to be generated, the interrupt unit of the present invention receives an interrupt signal from the processor with associated metadata. This metadata may include handler flags, e.g., non-zero values that identify one of the following interrupt handlers: normal interrupt handler, pre handler, or post handler. If a pre handler flag is set in the metadata, rather than fetching instructions from the normal interrupt handler as described above, the interrupt unit notifies the processor to fetch instructions from the pre handler routine that records trace data occurring prior to execution of the “normal” interrupt handler, at a particular instant of time. A “normal” interrupt handler, as the term is used in this description, refers to the interrupt handling routine that would execute based on the interrupt generated if the pre and/or post flags were not set. The trace data generated by the pre handler routine may include a ‘to’ and/or ‘from’ address of the instruction where the interrupt occurs and selected performance monitoring information. A timestamp may also be included in the trace record. Once the pre handler routine is executed, the pre handler notifies the processor to fetch instructions from the normal interrupt handler. When the normal interrupt handler execution is complete, if the post handler flag is set, the interrupt unit of the present invention notifies the processor to fetch instructions from the post handler to record trace data for an interrupt at a particular instant of time after the normal interrupt handler. In this way, the pre and post handlers allow trace data specific to a particular trap or interrupt at a particular instant of time to be recorded without making modification to any operating system routines. Using the pre and post handlers, trace records may be logged prior to execution of a normal trap or interrupt handling routine, such as in response to the taking of a branch, and immediately after execution of a normal trap or interrupt handling routine. From the information generated by the pre and post handlers, a picture of what is happening in the computer program execution between the time when a branch instruction is executed to the time when a branch is taken, and between the time after a branch is taken and returning to normal execution, may be obtained. In addition, performance trace data may be recorded at the entrance and exit of the normal trap or interrupt handling routine in order to identify changes that occur between the time when a particular interrupt occurs to the start of the trap or interrupt handling routine. In addition, changes that occur between the end of the trap or interrupt handling routine and the interrupt return may also be identified. This information provides engineers with a tool to separate events that occur during normal execution of the system from events that occur when the system is interrupted or a branch is taken. In yet another preferred embodiment, the pre and post handler routines may be implemented to perform other functions, such as handling overflow of the count used by the performance monitoring unit to count events. The performance monitoring unit may be implemented as performance monitoring unit 240 in FIG. 2. The count may be stored either in the IDT or in a dedicated memory location outside of the IDT. Because an overflow may occur during counting of events, the pre and post handler routines may look up the value of the count periodically to check for overflow. In one embodiment, if the value of the count is about to wrap, the pre and post handler routines may signal the processor that an overflow will occur. In another embodiment, the pre and post handlers may include routines that handle the overflow, for example, by reading and resetting the count value. Turning next to FIG. 3, an exemplary diagram illustrating components for recording events of an interrupt using pre and post handler is depicted in accordance with a preferred embodiment of the present invention. In this example implementation, the central processing unit (CPU) 302 may be implemented as processor 210 in FIG. 2. In a preferred embodiment, when a branch instruction is executed, a trap is executed by the application program. The trap notifies CPU 302 to generate and send a signal to interrupt unit 304 indicating that an exception has occurred, meaning the branch instruction is executed. Interrupt unit 304 notifies CPU 302 to fetch instructions from the pre handler to record trace data prior to taking a branch. The pre handler routine records trace data, which may include a ‘from’ address where the branch instruction is executed, the ‘to’ address of where to branch and performance information, e.g., count values, of selected performance events that occurred, prior to taking a branch. After the execution of the trap handling routine, an indication of the completion of the trap handling routine is returned to the interrupt unit 304. The interrupt unit 304 then notifies CPU 302 to fetch instructions from the post handler to record trace data prior to returning to normal execution. In an alternative embodiment, when an interrupt occurs, such as when a cache miss occurs during program execution, CPU 302 sends a signal to interrupt unit 304 with associated metadata that identifies the type of interrupt, which is used to identify the particular interrupt handling routine that is to be executed to handle the interrupt. Interrupt unit 304 may then identify the address in the IDT and notifies the processor to fetch instructions from the interrupt handling routine at the address identified in the IDT based on the interrupt type indicated in the metadata. This may involve fetching instructions from an address for a pre and/or post handler that is stored in association with the handler identified by the metadata, as described hereafter. Turning next to FIG. 4, an exemplary diagram illustrating an example interrupt description table (IDT) is depicted in accordance with a preferred embodiment of the present invention. In this example implementation, an interrupt descriptor table (IDT) 402 includes memory addresses 404, interrupt types 406, pre handler addresses 408 and post handler addresses 410. Interrupt types 406 represented in IDT 402 are for illustrative purpose only. In this example, when an interrupt occurs such as, for example, a Virtual Hash Page Table (VHPT) data fault interrupt, which is an interrupt associated Virtual Hash Page Table, the processor sends a signal identifying the occurrence of the interrupt to an interrupt unit, such as interrupt unit 304 in FIG. 3. The interrupt unit checks metadata 400 associated with the signal to determine if pre or post handlers are enabled for handling the identified interrupt. In this example, the metadata is 01, which means the pre handler is enabled. If the metadata is 00, the normal interrupt handler is enabled; if the metadata is 10, the post handler is enabled. If the metadata is set to 11, both the pre handler and the post handler are enabled. Whether the metadata is set to 01, 00, 10 or 11 may be determined based on, for example, a data structure associated with the performance monitoring applications that are used to monitor the execution of the computer program. That is, a user may set whether pre handlers, post handlers, both, or neither are enabled for a particular type of event or for a particular trace, via user input to the performance monitoring application. This information may be stored in a data structure associated with the performance monitoring application which may be accessed to set registers associated with the processor indicating whether to enable pre handlers, post handlers, both or neither. Alternatively, this information may be maintained in a data structure that is accessed by the processor or the interrupt unit each time there is a trap or interrupt generated to determine whether that particular trap or interrupt is associated with an enabled pre handler, post handler, both or neither. This data structure may be, for example, the IDT, a shadow IDT data structure, or other data structure. In another embodiment, a register may be used to indicate the address of a pre handler and a different register for a post handler. The value of zero means there is no pre or post handler and a non-zero value indicates the address of the pre or post handler. This approach allows one pre handle and one post handler for all traps. [Please note that is probably the preferred embodiment and should definitely be in the claims.] If the pre handler is enabled, the interrupt unit identifies the pre handler routine address 408, in this example 0x4000 412, from pre handler address field 408 of IDT 402 associated with the interrupt type indicated in the received signal from the processor and executes the corresponding pre handler routine 422 starting at memory address 0x4000 424 to record events. Once pre handler routine 422 is executed, the interrupt unit identifies starting memory address 404 of the VHPT data fault interrupt service routine from memory address field 404 of IDT 402, in this example 0x0000 426 and notifies the processor to execute the normal interrupt service routine of the interrupt handler. Once the normal interrupt service routine is complete, the processor sends a signal to the interrupt unit 304 in FIG. 3. The interrupt unit checks metadata 400, which is associated with the signal sent by the processor in response to the interrupt occurring, to determine whether the post handler is also enabled. If the post handler is enabled, the interrupt unit 304 identifies post handler routine starting address 410, in this example 0x5000 442, from post handler address field 410 of IDT 402. The interrupt unit then notifies the processor to execute corresponding post handler routine 440 starting at memory address 0x5000 442 to record events. Once post handler routine 440 is executed, the interrupt unit then notifies the processor to return to the original instructions of the computer program that caused the interrupt. Turning next to FIG. 5, a flowchart outlining an exemplary process for recording events of an interrupt using pre and post handlers from the interrupt unit's perspective is depicted in accordance with a preferred embodiment of the present invention. The process begins when the processor, in response to executing a trap instruction or an interrupt being generated, sends a signal with associated metadata to the interrupt unit (step 502). Next, a determination is made as to whether the pre handler is enabled based on the metadata associated with the signal (step 504) by examining the flag set in the metadata. If the pre handler is not enabled, the interrupt unit identifies the memory address of the normal interrupt handling routine, such as memory address 404 in FIG. 4, corresponding to the interrupt type, such as interrupt type 406 in FIG. 4 (step 510) in the IDT, such as IDT 402 in FIG. 4 and notifies the processor to execute the interrupt handling routine (step 512). If the pre handler is enabled, the interrupt unit identifies the starting address of the pre handler routine (step 506) and notifies the processor to execute the pre handler routine (step 508) to record events. The interrupt unit then notifies the processor the memory address of the interrupt handling routine corresponding to the interrupt type (step 510) in the IDT, in order to execute the interrupt handling routine (step 512). Once the processor executes the interrupt handling routine, the interrupt unit then identifies the post handler address that corresponds to the interrupt type or IDT entry in the IDT (step 514). A determination is made as to whether the post handler is enabled based on the metadata (step 516). If the post handler is not enabled, the interrupt unit notifies the processor to return to the original execution (step 522). The process terminates thereafter. If the post handler is enabled, the interrupt unit identifies the starting address of the post handler routine (step 518). The interrupt unit then notifies the processor to execute the post handler routine (step 520) to record events before returning to original execution (step 522). The process then terminates thereafter. Turning next to FIG. 6, a flowchart outlining an exemplary process for logging trace records when a branch instruction is executed with trap on branch using pre and post handlers from the interrupt unit's perspective is depicted in accordance with a preferred embodiment of the present invention. The process begins when the processor, in response to a branch instruction being executed, sends a signal to the interrupt unit indicating that a branch instruction is executed (step 602). The interrupt unit, such as interrupt unit 304 in FIG. 3, then notifies the processor to execute instructions from the pre handler routine (step 604). Next, the branch instruction is executed to take a branch (step 606). Consequently, the interrupt unit notifies the processor to execute instructions from the post handler to record trace data (step 610) prior to returning to normal execution (step 612), the process terminating thereafter. Thus, the present invention provides a solution of recording performance data without modifying application and/or system code at run time. Pre and post handlers are provided to process performance information in various ways. One example may be by accumulating values of events that occurred to be used by a performance analysis tool. In addition, the pre and post handler may record trace data with “trap on branch” conditions when a branch instruction is executed. The pre and post handler may also be used to record precise performance data for events occurring before entering and immediately after exiting an interrupt handler. The recorded values provide engineers with a tool to separate events that occur during normal execution of the system from events that occur when the system is interrupted, in order to better optimize the system. It is important to note that while the present invention has been described in the context of a fully functioning data processing system, those of ordinary skill in the art will appreciate that the processes of the present invention are capable of being distributed in the form of a computer readable medium of instructions and a variety of forms and that the present invention applies equally regardless of the particular type of signal bearing media actually used to carry out the distribution. Examples of computer readable media include recordable-type media, such as a floppy disk, a hard disk drive, a RAM, CD-ROMs, DVD-ROMs, and transmission-type media, such as digital and analog communications links, wired or wireless communications links using transmission forms, such as, for example, radio frequency and light wave transmissions. The computer readable media may take the form of coded formats that are decoded for actual use in a particular data processing system. The description of the present invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to best explain the principles of the invention, the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Technical Field The present invention relates generally to an improved data processing system and, in particular, to a method and system for monitoring performance of the processor in a data processing system when an interrupt occurs. Still more particularly, the present invention relates to a method, apparatus, and computer instructions for providing pre handlers and post handlers to record events. 2. Description of Related Art A typical data processing system utilizes processors to execute a set of instructions in order to perform a certain task, such as reading a specific character from the main memory. However, as the number of tasks required to be executed by the processor increases, the efficiency of the processor's access patterns to memory and the characteristics of such access become important factors for engineers who want to optimize the system. Currently, the prior art contains mechanisms that can count occurrences of software-selectable events, such as, for example, cache misses, instructions executed, I/O data transfer request, and the time a given process may take to execute within a data processing system. One such mechanism is a performance monitor. A performance monitor monitors selected characteristics for system analysis by determining a machine's state at a particular time. This analysis provides information of how the processor is used when instructions are executed and its interaction with the main memory when data is stored. This analysis may also be used to determine if application code changes, such as a relocation of branch instructions and memory access, to further optimize the performance of a system are necessary. In addition, the performance monitor may provide the amount of time that has passed between events in a processing system. The performance monitor counts events that may be used by engineers to analyze system performance. Moreover, data regarding how the processor accesses the data processing system's level 1 and level 2 cache, and main memory may be gathered by the performance monitor in order to identify performance bottlenecks that are specific to a hardware or software environment. In addition to the performance monitor described above, an interrupt processing unit may be used to record events such as, for example, instruction execution, branch events, or system events when an interrupt occurs. An interrupt occurs when a device, such as a mouse or keyboard, raises an interrupt signal to notify the processor that an event has occurred. When the processor accepts an interrupt request, the processor completes its current instruction and passes the control to an interrupt handler. The interrupt handler executes an interrupt service routine that is associated with the interrupt. An interrupt may also be caused by a specific machine language operation code, for example Motorola 68000's TRAP, a product from Motorola, Inc. In this case, an unexpected software condition such as divide by zero causes the processor to store the current state, store identifying information about the particular interrupt and pass control to an interrupt handler that handles this unexpected software condition. However, the performance monitor above must modify the application program at run time in order to record precise performance trace data, such as the number of instructions executed during interrupt processing. Therefore, it would be advantageous to have an improved method, apparatus, and computer instructions for providing pre and post handlers to record precise performance data for events occurring before entering and immediately after exiting an interrupt handler without modifying underlying application program. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention provides a method, apparatus, and computer instructions for providing pre and post handlers to record events when an interrupt occurs. The pre and post handlers allow logging of trace records along with timestamps associated with performance monitoring events to be recorded in order to provide the user with more fine-grained performance data. In a preferred embodiment, the mechanism of the present invention provides pre and post handlers to record the occurrence of performance monitoring events when a branch instruction is executed. The pre and post handlers are used with a “trap on branch”, i.e. a trap, or interrupt, being processed when a branch instruction is executed, to produce an instruction trace which includes the ‘from’ address of where the branch is taken and may include the ‘to’ address of where the branch branches to. It should be clear that information could be compressed in various ways to minimize the amount of information to be recorded. The pre and post handlers record performance monitoring events occurring prior to and immediately after taking the branch. In an alternative embodiment, before the processor fetches instructions from the interrupt handler when an interrupt occurs, the mechanism of the present invention allows the pre handler to log trace records prior to entering the interrupt handler. The events recorded provide the state of the system when entering an interrupt handler. When the interrupt handler completes the interrupt service routine, the mechanism of the present inventions allows the post handler to record events and low level information, such as the number of instructions executed for an interrupt, before returning to normal execution. This low-level information may provide the state of the system when exiting an interrupt. These and other features and advantages will be discussed in, or will become apparent to those of ordinary skill in the art in view of, the following detailed description of the preferred embodiments. | 20040114 | 20070327 | 20050714 | 85216.0 | 0 | PHAN, RAYMOND NGAN | METHOD AND SYSTEM FOR RECORDING EVENTS OF AN INTERRUPT USING PRE-INTERRUPT HANDLER AND POST-INTERRUPT HANDLER | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,757,221 | ACCEPTED | On-location electronics troubleshooting services system | A method and system for providing on-location troubleshooting services to homeowners and businesses for low-voltage electronic equipment and other on-location services. It employs the use of an Internet-based system for recording customer requests for service and subsequently automatically dispatching technicians and managing provision of the requested services. It also provides functions to support customer and technician recruitment and sign up. Additionally, it provides functions for recording customer satisfaction, requesting repair services and links to low-voltage electronics equipment suppliers for purchasing desired low-voltage electronics equipment. Service areas, work cells are established for groups of customers which are closely located geographically. Technicians are recruited and assigned responsibility for work cells based on whether their residence is in or close to a particular work cell or group of work cells. Customers and technicians may also access certain functions of the Internet-based system through telephones and telephone interface to the Internet-based system. | 1) An Internet-website-client-server-assisted system, relating to providing on-location electronics troubleshooting services, comprising the steps of: a) registering customer information relating to at least one customer; b) registering technician information relating to at least one technician having electronics-technician abilities relating to providing such on-location electronics troubleshooting services; c) maintaining a database, on at least one Internet website client server, of such customer information relating to such at least one customer; d) maintaining a database, on such at least one Internet website client server, of such technician information relating to such at least one technician; e) collecting automatically, using such at least one Internet website client server, at least one fee from such at least one customer relating to such on-location electronics troubleshooting services; f) receiving, on such at least one Internet website client server, requests relating to such on-location electronics troubleshooting services from such at least one customer; g) notifying automatically, using such at least one Internet website client server, such at least one technician to provide such on-location electronics troubleshooting services requested by such at least one customer; h) receiving on-location electronics troubleshooting service information, on at least one Internet website client server, from such at least one technician; and i) maintaining a database, on such at least one Internet website client server, of such on-location electronics troubleshooting service information. 2) The Internet-website-client-server-assisted system according to claim 1 wherein such at least one customer and such at least one technician are sufficiently co-located within geographical areas to provide appropriate response times. 3) The Internet-website-client-server-assisted system according to claim 2, wherein such step of receiving on-location electronics troubleshooting service information by such at least one technician comprises the steps of: a) receiving start time of such on-location electronics troubleshooting service, on such at least one Internet website client server, from selected such at least one technician; b) receiving end time of such on-location electronics troubleshooting services, on such at least one Internet website client server, from selected such at least one technician; c) storing such start time of such on-location electronics troubleshooting service on such at least one Internet website client server; and d) storing such end time of such on-location electronics troubleshooting service on such at least one Internet website client server. 4) The Internet-website-client-server-assisted system according to claim 3 further comprising the steps of: a) receiving indication of any need relating to repair service, on such at least one Internet website client server, from such selected at least one technician; b) receiving indication of selected type of such repair service, on such at least one Internet website client server, from such selected at least one technician; c) storing such indication of any need relating to repair service on such at least one Internet website client server; d) storing such selected type of such repair service, on such at least one Internet website client server; e) selecting such at least one repair service of such selected type of repair service; and f) notifying such selected at least one repair service to contact such at least one customer. 5) The Internet-website-client-server-assisted system according to claim 3 further comprising the steps of: a) receiving customer satisfaction evaluation from such selected at least one technician; and b) storing such customer satisfaction evaluation. 6) The Internet-website-client-server-assisted system according to claim 2, wherein such step of collecting automatically, using such at least one Internet website client server, at least one fee from such at least one customer relating to such on-location electronics troubleshooting services comprises the steps of: a) agreeing to at least one payment of a specified amount by such at least one customer; and b) receiving such at least one payment. 7) The Internet-website-client-server-assisted system according to claim 6, wherein such step of receiving such at least one payment comprises the steps of; a) providing of credit card account information by such at least one customer; b) storing such at least one credit card account information, on at least one Internet website client server, relating to such at least one customer; c) authorizing at least one charge to such credit card account of such at least one customer; d) storing such authorization of at least one charge to such credit card account, on at least one Internet website client server, of such at least one customer; e) requesting at least one payment from such at least one credit card account on behalf of such at least one customer; and f) recording such at least one payment, on at least one Internet website client server, on behalf of such at least one customer. 8) The Internet-website-client-server-assisted system according to claim 7, wherein such step of requesting at least one payment from such at least one credit card account on behalf of such at least one customer comprises the step of requesting such at least one payment from such at least one credit card account on behalf of such at least one customer substantially automatically at pre-determined intervals. 9) The Internet-website-client-server-assisted system according to claim 7, wherein such step of requesting at least one payment from such at least one credit card account on behalf of such at least one customer comprises the step of requesting such at least one payment from such at least one credit card account on behalf of such at least one customer at completion of on-location electronics troubleshooting services by such at least one technician. 10) The Internet-website-client-server-assisted system according to claim 2 further comprising the steps of: a) notifying such at least one customer requesting such on-location electronics troubleshooting services of estimated time of arrival of notified such at least one technician; and b) providing such on-location electronics troubleshooting services to such at least one customer. 11) The Internet-website-client-server-assisted system according to claim 10 wherein such step of notifying such at least one customer requesting such on-location electronics troubleshooting services of estimated time of arrival of notified such at least one technician comprises the steps of: a) providing to such at least one customer such estimated time of arrival by such notified such at least one technician; and b) recording such estimated time of arrival provided by such notified such at least one technician. 12) The Internet-website-client-server-assisted system according to claim 10 further comprising the steps of: a) providing such on-location electronics troubleshooting services to such at least one customer at any time of day; and b) providing such on-location electronics troubleshooting services to such at least one customer on any day. 13) The Internet-website-client-server-assisted system according to claim 2, wherein such step of registering customer information relating to at least one customer further comprises the steps of: a) recruiting such at least one customer; b) obtaining agreement from such at least one customer to pay for such on-location electronics troubleshooting services; c) recording such customer information, on at least one Internet website client server, relating to such at least one customer; d) wherein such customer information comprises i) service location address; ii) at least one contact name; iii) at least one contact telephone number; and e) assigning such service location address to at least one geographic dispatch area. 14) The Internet-website-client-server-assisted system according to claim 13, wherein such customer information further comprises: a) customer name; b) customer billing address; c) customer email address; d) customer credit card number; and e) customer credit card number expiration date. 15) The Internet-website-client-server-assisted system according to claim 13 further comprising the steps of: a) providing on-location assistance relating to implementation of such on-site customer interface module of such Internet-website-client-server-assisted system to such at least one customer; and b) providing on-location usage training relating to such on-site customer interface module of such Internet-website-client-server-assisted system to such at least one customer. 16) The Internet-website-client-server-assisted system according to claim 2, wherein such step of registering technician information relating to at least one technician having electronics-technician abilities relating to providing such on-location electronics troubleshooting services comprises the steps of: a) establishing a plurality of qualification criteria relating to selecting such at least one technician; b) wherein such qualification criteria comprise i) geographic location of residence of such at least one technician, and ii) required minimum competency levels relating to electronics-technician abilities; and c) recruiting such at least one technician; and d) recording technician information, on at least one Internet website client server, relating to selected such at least one technician; e) wherein such technician information comprises i) technician name, ii) technician home address, iii) technician home telephone number, iv) technician email address, and v) technician electronics-technician skills; f) selecting such at least one technicians using such plurality of qualification criteria; g) assigning such selected at least one technician a unique identification number; h) assigning such technician home address to at least one geographic dispatch area; and i) implementing at least one technician user interface module of such Internet-website-client-server-assisted system. 17) The Internet-website-client-server-assisted system according to claim 16, wherein such technician information further comprises: a) technician cellular phone number; and b) technician pager number. 18) The Internet-website-client-server-assisted system according to claim 2 wherein such step of receiving, on such at least one Internet website client server, requests relating to such on-location electronics troubleshooting services from such at least one customer comprises the steps of: a) inputting of login identification information, on such at least one Internet website client server, from such at least one customer; b) validating login identification information from such at least one customer; c) receiving confirmation of accuracy, on such at least one Internet website client server, of such customer information; d) receiving contact information, on such at least one Internet website client server, relating to such current at least one on-location electronics troubleshooting request; e) submitting of at least one problem description relating to such current at least one on-location electronics troubleshooting request by such at least one customer; and f) receiving of such at least one problem description relating to such current at least one on-location electronics troubleshooting request, on such at least one Internet website client server, from such at least one customer. 19) The Internet-website-client-server-assisted system according to claim 2, wherein such step of notifying automatically, using such at least one Internet website client server, such at least one technician to provide such on-location electronics troubleshooting services requested by such at least one customer comprises the steps of: a) selecting such at least one technician using dispatch selection criteria; b) wherein such dispatch selection criteria comprises i) identifying at least one of such at least one technician assigned to such same geographic dispatch area as such service location of such at least one customer requesting on-location electronics troubleshooting services, and ii) identifying at least one such technician having greatest elapsed time since such last notification; and c) notifying such at least one technician to provide such on-location electronics troubleshooting services requested by such at least one customer; and d) recording time of such notification, on such at least one Internet website client server, of such at least one technician. 20) The Internet-website-client-server-assisted system according to claim 2 further comprising the steps of: a) receiving at least one work shift start request, on such at least one Internet website client server, from such at least one technician; b) storing time of day and date of receipt of such work shift start request, on such at least one Internet website client server, from such at least one technician; c) sending confirmation of start of work shift to such at least one technician; d) receiving at least one end of work shift request, on such at least one Internet website client server, from such at least one technician; e) storing time of day and date of receipt of such at least one end of work shift request, on such at least one Internet website client server, from such at least one technician; and f) sending confirmation of end of work shift to such at least one technician. 21) The Internet-website-client-server-assisted system according to claim 20 further comprising the step of presenting planned shift scheduling to such at least one technician. 22) The Internet-website-client-server-assisted system according to claim 2 further comprising the steps of: a) preparing text-based reports; and b) preparing graphical reports. 23) An Internet website client-server computer system relating to providing on-location electronics troubleshooting services comprising, in combination: a) computer interface and storage means for registering customer data relating to at least one customer; b) computer interface and storage means for registering technician data relating to at least one technician having electronics-technician abilities relating to providing such on-location electronics troubleshooting services; c) database means for maintaining a database of such customer data relating to such at least one customer; d) database means for maintaining a database of such technician data relating to such at least one technician; e) computer processor means for managing collecting at least one fee from such at least one customer relating to such on-location electronics troubleshooting services; f) computer interface and storage means for receiving requests relating to such on-location electronics troubleshooting services from such at least one customer; g) computer processor and communications-device means for automatically notifying such at least one technician to provide such on-location electronics troubleshooting services requested by such at least one customer; and h) computer interface and storage means for recording on-location electronics troubleshooting service information. 24) The Internet website client-server computer system according to claim 23 further comprising: a) computer processor means for substantially fully automating such dispatching of such at least one technician to such at least one customer relating to such on-location troubleshooting. 25) The Internet website client-server computer system according to claim 24 further comprising: a) computer processing means for selecting such at least one technician using dispatch selection criteria; b) wherein such dispatch selection criteria comprises i) such at least one technician assigned to such same geographic dispatch area of such at least one customer requesting on-location electronics troubleshooting services, and ii) such at least one technician having greatest elapsed time since last such dispatch; and c) communications device means for notifying such at least one technician to provide such on-location electronics troubleshooting services requested by such at least one customer; and d) computer processor means for recording time of such notification of such at least one technician. 26) The Internet website client-server computer system according to claim 23, wherein such computer processor means for managing collecting at least one fee from such at least one customer relating to such on-location electronics troubleshooting services further comprises: a) computer interface and storage means for receiving credit card account information from such at least one customer; b) computer processor and communications means for requesting payment from such at least one credit card account on behalf of such at least one customer; and c) computer processor means for recording such payment on behalf of such at least one customer. 27) The Internet-website-client-server-assisted system according to claim 26, wherein such computer processor and communications means for requesting payment from such at least one credit card account on behalf of such at least one customer comprises computer processor and communications means for requesting such at least one payment from such at least one credit card account on behalf of such at least one customer substantially automatically at pre-determined intervals. 28) The Internet-website-client-server-assisted system according to claim 26, wherein such computer processor and communications means for requesting payment from such at least one credit card account on behalf of such at least one customer comprises computer processor and communications means for requesting such at least one payment from such at least one credit card account on behalf of such at least one customer at completion of on-location electronics troubleshooting services by such at least one technician. 29) The Internet website client-server computer system according to claim 23, wherein such computer interface and storage means for receiving requests relating to such on-location electronics troubleshooting services from such at least one customer further comprises: a) computer interface means for inputting login identification information by such at least one customer; b) computer processing means for validating login identification information from such at least one customer; c) computer interface means for receiving confirmation of accuracy of such customer information; d) computer interface and storage means for receiving contact information relating to such current at least one on-location electronics troubleshooting request; and e) computer interface and storage means for receiving at least one problem description relating to such current at least one on-location electronics troubleshooting request by such at least one customer. 30) The Internet website client-server computer system according to claim 23, further comprising: a) computer interface and storage means for receiving at least one work shift start request from such at least one technician; b) computer interface means for presenting confirmation of start of work shift to such at least one technician; c) computer interface and storage means for receiving at least one end of work shift request from such at least one technician; d) computer interface means for presenting confirmation of end of work shift to such at least one technician; e) computer interface means for presenting planned shift scheduling to such at least one technician; f) computer interface and processor means for presenting text reports; and g) computer interface and processor means for presenting graphical reports. 31) The Internet website client-server computer system according to claim 23, wherein such computer interface and storage means for recording on-location electronics troubleshooting service information further comprises: a) computer interface and storage means for receiving start time of such on-location electronics troubleshooting service from such selected at least one technician; b) computer interface and storage means for receiving end time of such on-location electronics troubleshooting services from such selected at least one technician; c) computer interface and storage means for receiving indication of any need relating to repair service from such selected at least one technician; d) computer interface and storage means for receiving indication of selected type of such repair service from such selected at least one technician; e) computer processor means for selecting such at least one repair service of such selected type of repair service; f) communications device means for notifying such selected at least one repair service to contact such at least one customer; and g) computer interface and storage means for receiving customer satisfaction evaluation. 32) At least one network-client-server-assisted system, relating to assisting providing services to at least one customer, comprising the steps of: a) maintaining a database on such at least one network-client-server-assisted system of customer-assistance information relating to such at least one customer; b) receiving, on such at least one network-client-server-assisted system, requests relating to such services from such at least one customer; and c) notifying automatically, using such at least one network-client-server-assisted system, at least one service provider to provide such services requested by such at least one customer. | CROSS-REFERENCES TO RELATED APPLICATIONS The present application claims priority from and is related to applicant's prior U.S. Provisional Application Ser. No. 60/439,998, filed Jan. 13, 2003, entitled “On-Location Electronics Troubleshooting Services System”, and claims priority from and is related to U.S. Provisional Application Ser. No. 60/484,298, filed Aug. 11, 2003, entitled “On-Location Electronics Troubleshooting Services System”, the contents of all of which are hereby herein incorporated by reference and are not admitted to be prior art with respect to the present invention by their mention in this cross-reference section. BACKGROUND This invention relates to a system for providing on-location electronics troubleshooting services to consumers and businesses in a manner that improves timeliness and quality of responses to requests for assistance. This system is made possible by the widespread availability of the Internet and improvements in related software. In the past few years, the pace of change in low voltage electronics has accelerated and is likely to continue into the future. Low voltage electronics, typified by personal computers, also includes video and stereo equipment and all manner of devices from telephones to personal digital assistants. Not only has the number of devices increased, but their complexity has increased to the point where many are no longer installable without significant assistance from retailers and manufacturers. The increase in the number and complexity of low-voltage devices has made it increasingly difficult to troubleshoot problems when they inevitably arise. Recent economic troubles have forced many low-voltage manufacturers and dealers to reduce live telephone-based customer support as well in favor or email exchanges, FAQ (Frequently Asked Questions) lists or user forums. Even when support is available, it is often of marginal quality due to the low skill level of telephone support representatives and it has inherent limitations of time of day and the ability of the two parties to communicate clearly about a problem. Email exchanges and user forums are often time-consuming and require more knowledge than the user has and usually require multiple days to receive an answer, which answer has a high likelihood of being incorrect. FAQ lists can be helpful, but are usually limited to addressing only the most basic issues. Today, beyond telephone support, the sources of assistance for consumers and small businesses are typically limited to: on-location assistance provided on an on-call basis; or technically oriented friends or family. And using either of these alternatives often means delays in getting a problem resolved in a timely manner. On-location full time technical support staff, which would theoretically be more responsive, is never an option for consumers; and most small businesses are unable to afford the cost. Additionally, telephone-based support is less and less often provided at no charge. All the current alternatives are generally only available during business hours on business days; therefore, no help is available on nights and weekends. Consumers and small businesses are often forced to “live with a problem” for much longer than they would like or to pay a premium for on-location help on a one-time basis. Additionally, most problems encountered are not intrinsic failures of a device, but are grounded in misunderstandings, user ignorance, and errors by users during installation or set up. This means that most consumers' and small businesses' low-voltage technical problems can be resolved quickly by a technically competent person working at the consumer's or business's location. Furthermore, the problems faced by low-voltage devices manufacturers are common to a wide variety of other industries and service providers. Examples of other areas which face similar problems are services providers such as telephone companies, hotels, and information technology departments in large organizations and other service providers such as telephone and cable companies. Coincident with these changes in low-voltage devices, a wide range of interactive devices have been developed to provide information to a variety of users via communications networks. These interactive devices include, for example, computers connected to various computer on-line services, interactive kiosks, interactive television systems, and a variety of other wired and wireless devices, such as personal data assistants (PDA's) and the like. In particular, the popularity of computer on-line services has grown immensely in popularity over the last decade. Computer on-line services are provided by a wide variety of different companies. In general, most computer on-line services are accessed via the Internet. The Internet is a global network of computers. One popular part of the Internet is the World Wide Web, or the “Web.” The World Wide Web contains computers that display graphical and textual information. Computers that provide information on the World Wide Web are typically called “Websites.” A Website is defined by an Internet address that has an associated electronic page, often called a “homepage.” Generally, a homepage is an electronic document that organizes the presentation of text, graphical images, audio and video into a desired display. These Websites are operated by a wide variety of entities, which are typically called “providers”. A user may access the Internet via a dedicated high-speed line or by using a personal computer (PC) equipped with a conventional modem or a variety of other wired and wireless devices. Special interface software, called “browser” software, is installed within the PC or other access device. When the user wishes to access the Internet by normal telephone line, an attached modem is automatically instructed to dial the telephone number associated with the local Internet host server. The user can then access information at any address accessible over the Internet. Two well-known web browsers, for example, are the Netscape Navigator browser marketed by Netscape Communications Corporation and the Internet Explorer browser marketed by Microsoft Corporation. Information exchanged over the Internet is typically encoded in HyperText Mark-up Language (HTML) format. The HTML format is a scripting language that is used to generate the homepages for different content providers. In this setting, a content provider is an individual or company that places information (content) on the Internet so that others can access it. As is well known in the art, the HTML format is a set of conventions for marking different portions of a document so that each portion appears in a distinctive format. For example, the HTML format identifies or “tags” portions of a document to identify different categories of text (e.g., the title, header, body text, etc.). When a web browser (or suitable executable program) accesses an HTML document, the web browser (or suitable executable program) reads the embedded tags in the document so it appears formatted in the specified manner. An HTML document can also include hyperlinks, which allow a user to move from one document to another document on the Internet. A hyperlink is an underlined or otherwise emphasized portion of text that, when selected using an input device such as a mouse, activates a software connection module that allows the user to jump between documents or pages (i.e., within the same Website or to other Websites). Hyperlinks are well known in the art, and have been sometimes referred to as anchors. The act of selecting the hyperlink is often referred to as “clicking on” the hyperlink. The advent and subsequent increased use of the Internet and its interconnected communications systems, coupled with new wireless technologies, may provide an opportunity for the development of new and advanced methods of providing skilled, timely on-location electronics troubleshooting services at a reasonable cost to the customer. Additionally, a variety of other industries which provide some form of on-site service and support are also faced with problems and requirements are similar to those faced by the low-voltage electronics industry. For example, hotels often have difficulty managing requests for deliveries to guest's rooms. Frequently guests request delivery of toiletries, food, etc., be to their room. Today, the requester (person or people) must call the front desk. Typically, person the front desk must in turn request that someone else deliver the requested items. This process presents a number of problems including no consistent way to track requests and deliveries of those items, difficulty in monitoring performance and completion, the involvement of several people and no tracking of the frequency of requests by the type of request, deliveries, repairs, etc. Another example, many companies use call centers (not always in the US) to provide customer support. At best these can be frustrating and time consuming experiences for customers because it is frequently difficult to find the right person to help resolve the problem. This leads to unhappy customers and the need to maintain large call centers with their attendant expense. A further example, information technology departments for many companies manage and process thousands of requests for help and service. Frequently, this support effort suffers from communications methods that ensure the highest priority problems are addressed first. Additionally, while voice mail and other forms of communication permit leaving a message with a person they do not permit centralized management including prioritization and assignment of the requests. Thus, problems are not resolved on timely basis and the support staff must each deal with conflicting priorities and frequent changes in work. A final example, high rise building managers must deal with a constant flow of incoming service requests by tenants to the building manager. The building manager must then request the services of a trade contractor to address the problem. Finally the building manager must then follow up to ensure the problem is resolved. All this is typically very disjointed requiring many phone calls and time and effort for many people which results in improper work, late completions and unhappy tenants and trades contractors. This opportunity is also applicable to a variety of other industries which provide some form of on-site service and support because their problems and requirements are similar to those faced by the low-voltage electronics industry. Such new and advanced methods (such as the inventions provided herein by applicant) of providing on-location support solve many of the current problems outlined above. OBJECTS OF THE INVENTION A primary object and feature of the present invention is provide a solution to these above-mentioned problems of the prior art by presenting a new and effective system for on-location electronics troubleshooting and similar services, typically available essentially 24 hours per day 365 days per year using skilled technicians—a new approach to troubleshooting by thinking “out of the box”. It is a further object and feature of the present invention to provide a system for managing customer communications of needs (whether involving repair or troubleshooting) and automatically dispatching technicians, with little or no human involvement, to the customers' locations based on a request from a respective customer. It is a further object and feature of the present invention to provide a system which assists in the management of technicians and their work shift schedules with minimal supervisory involvement. It is still another object and feature of such a system to assist in recording completion of customers' troubleshooting requests and their satisfaction with the technician's work. A further primary object and feature of the present invention is to provide such a system to permit customers to pay for the services in a variety of ways, including paying a monthly fee not directly related to the number of troubleshooting requests, paying a fee for each service request, or other combinations. It is another object and feature of the present invention to link with selected electronics suppliers to permit customers to purchase products for delivery at any time of day on any day. Further, it is another object and feature of the present invention to permit customers to request on-location repairs from qualified electronics repair companies. It is yet another primary object and feature of the present invention to utilize the capabilities of the Internet-based on-location services management software to implement key functions and features of the invention. It is a further primary object and feature of the present invention to interface voice technology and the Internet-based on-location services management software to provide alternate methods of utilizing the invention. It is still another object and feature of the present invention to interface various wireless technologies with the Internet-based on-location services management software to implement key functions and features of the invention. A further primary object and feature of the present invention is to provide such a system that is efficient, inexpensive, and handy. Other objects and features of this invention will become apparent with reference to the following descriptions. SUMMARY OF THE INVENTION In accordance with a preferred embodiment hereof, this invention provides an Internet-website-client-server-assisted system, relating to providing on-location electronics troubleshooting services, comprising the steps of: registering customer information relating to at least one customer; registering technician information relating to at least one technician having electronics-technician abilities relating to providing such on-location electronics troubleshooting services; maintaining a database, on at least one Internet website client server, of such customer information relating to such at least one customer; maintaining a database, on such at least one Internet website client server, of such technician information relating to such at least one technician; collecting automatically, using such at least one Internet website client server, at least one fee from such at least one customer relating to such on-location electronics troubleshooting services; receiving, on such at least one Internet website client server, requests relating to such on-location electronics troubleshooting services from such at least one customer; notifying automatically, using such at least one Internet website client server, such at least one technician to provide such on-location electronics troubleshooting services requested by such at least one customer; receiving on-location electronics troubleshooting service information, on at least one Internet website client server, from such at least one technician; and maintaining a database, on such at least one Internet website client server, of such on-location electronics troubleshooting service information. Moreover, it provides such an Internet-website-client-server-assisted system wherein such at least one customer and such at least one technician are sufficiently co-located within geographical areas to provide appropriate response times. Additionally, it provides such an Internet-website-client-server-assisted system, wherein such step of receiving on-location electronics troubleshooting service information by such at least one technician comprises the steps of: receiving start time of such on-location electronics troubleshooting service, on such at least one Internet website client server, from selected such at least one technician; receiving end time of such on-location electronics troubleshooting services, on such at least one Internet website client server, from selected such at least one technician; storing such start time of such on-location electronics troubleshooting service on such at least one Internet website client server; and storing such end time of such on-location electronics troubleshooting service on such at least one Internet website client server. Also, it provides such an Internet-website-client-server-assisted system further comprising the steps of: receiving indication of any need relating to repair service, on such at least one Internet website client server, from such selected at least one technician; receiving indication of selected type of such repair service, on such at least one Internet website client server, from such selected at least one technician; storing such indication of any need relating to repair service on such at least one Internet website client server; storing such selected type of such repair service, on such at least one Internet website client server; selecting such at least one repair service of such selected type of repair service; and notifying such selected at least one repair service to contact such at least one customer. In addition, it provides such an Internet-website-client-server-assisted system further comprising the steps of: receiving customer satisfaction evaluation from such selected at least one technician; and storing such customer satisfaction evaluation. And, it provides such an Internet-website-client-server-assisted system, wherein such step of collecting automatically, using such at least one Internet website client server, at least one fee from such at least one customer relating to such on-location electronics troubleshooting services comprises the steps of: agreeing to at least one payment of a specified amount by such at least one customer; and receiving such at least one payment. Further, it provides such an Internet-website-client-server-assisted system, wherein such step of receiving such at least one payment comprises the steps of; providing of credit card account information by such at least one customer; storing such at least one credit card account information, on at least one Internet website client server, relating to such at least one customer; authorizing at least one charge to such credit card account of such at least one customer; storing such authorization of at least one charge to such credit card account, on at least one Internet website client server, of such at least one customer; requesting at least one payment from such at least one credit card account on behalf of such at least one customer; and recording such at least one payment, on at least one Internet website client server, on behalf of such at least one customer. Even further, it provides such an Internet-website-client-server-assisted system, wherein such step of requesting at least one payment from such at least one credit card account on behalf of such at least one customer comprises the step of requesting such at least one payment from such at least one credit card account on behalf of such at least one customer substantially automatically at pre-determined intervals. Moreover, it provides such an Internet-website-client-server-assisted system, wherein such step of requesting at least one payment from such at least one credit card account on behalf of such at least one customer comprises the step of requesting such at least one payment from such at least one credit card account on behalf of such at least one customer at completion of on-location electronics troubleshooting services by such at least one technician. Additionally, it provides such an Internet-website-client-server-assisted system further comprising the steps of: notifying such at least one customer requesting such on-location electronics troubleshooting services of estimated time of arrival of notified such at least one technician; and providing such on-location electronics troubleshooting services to such at least one customer. Also, it provides such an Internet-website-client-server-assisted system wherein such step of notifying such at least one customer requesting such on-location electronics troubleshooting services of estimated time of arrival of notified such at least one technician comprises the steps of: providing to such at least one customer such estimated time of arrival by such notified such at least one technician; and recording such estimated time of arrival provided by such notified such at least one technician. In addition, it provides such an Internet-website-client-server-assisted system further comprising the steps of: providing such on-location electronics troubleshooting services to such at least one customer at any time of day; and providing such on-location electronics troubleshooting services to such at least one customer on any day. And, it provides such an Internet-website-client-server-assisted system, wherein such step of registering customer information relating to at least one customer further comprises the steps of: recruiting such at least one customer; obtaining agreement from such at least one customer to pay for such on-location electronics troubleshooting services; recording such customer information, on at least one Internet website client server, relating to such at least one customer; wherein such customer information comprises service location address; at least one contact name; at least one contact telephone number; and assigning such service location address to at least one geographic dispatch area. Further, it provides such an Internet-website-client-server-assisted system, wherein such customer information further comprises: customer name; customer billing address; customer email address; customer credit card number; and customer credit card number expiration date. Even further, it provides such an Internet-website-client-server-assisted system further comprising the steps of: providing on-location assistance relating to implementation of such on-site customer interface module of such Internet-website-client-server-assisted system to such at least one customer; and providing on-location usage training relating to such on-site customer interface module of such Internet-website-client-server-assisted system to such at least one customer. Moreover, it provides such an Internet-website-client-server-assisted system, wherein such step of registering technician information relating to at least one technician having electronics-technician abilities relating to providing such on-location electronics troubleshooting services comprises the steps of: establishing a plurality of qualification criteria relating to selecting such at least one technician; wherein such qualification criteria comprise geographic location of residence of such at least one technician, and required minimum competency levels relating to electronics-technician abilities; and recruiting such at least one technician; and recording technician information, on at least one Internet website client server, relating to selected such at least one technician; wherein such technician information comprises technician name, technician home address, technician home telephone number, technician email address, and technician electronics-technician skills; selecting such at least one technicians using such plurality of qualification criteria; assigning such selected at least one technician a unique identification number; assigning such technician home address to at least one geographic dispatch area; and implementing at least one technician user interface module of such Internet-website-client-server-assisted system. Additionally, it provides such an Internet-website-client-server-assisted system, wherein such technician information further comprises: technician cellular phone number; and technician pager number. Also, it provides such an Internet-website-client-server-assisted system wherein such step of receiving, on such at least one Internet website client server, requests relating to such on-location electronics troubleshooting services from such at least one customer comprises the steps of: inputting of login identification information, on such at least one Internet website client server, from such at least one customer; validating login identification information from such at least one customer; receiving confirmation of accuracy, on such at least one Internet website client server, of such customer information; receiving contact information, on such at least one Internet website client server, relating to such current at least one on-location electronics troubleshooting request; submitting of at least one problem description relating to such current at least one on-location electronics troubleshooting request by such at least one customer; and receiving of such at least one problem description relating to such current at least one on-location electronics troubleshooting request, on such at least one Internet website client server, from such at least one customer. In addition, it provides such an Internet-website-client-server-assisted system, wherein such step of notifying automatically, using such at least one Internet website client server, such at least one technician to provide such on-location electronics troubleshooting services requested by such at least one customer comprises the steps of: selecting such at least one technician using dispatch selection criteria; wherein such dispatch selection criteria comprises identifying at least one of such at least one technician assigned to such same geographic dispatch area as such service location of such at least one customer requesting on-location electronics troubleshooting services, and identifying at least one such technician having greatest elapsed time since such last notification; and notifying such at least one technician to provide such on-location electronics troubleshooting services requested by such at least one customer; and recording time of such notification, on such at least one Internet website client server, of such at least one technician. And, it provides such an Internet-website-client-server-assisted system further comprising the steps of: receiving at least one work shift start request, on such at least one Internet website client server, from such at least one technician; storing time of day and date of receipt of such work shift start request, on such at least one Internet website client server, from such at least one technician; sending confirmation of start of work shift to such at least one technician; receiving at least one end of work shift request, on such at least one Internet website client server, from such at least one technician; storing time of day and date of receipt of such at least one end of work shift request, on such at least one Internet website client server, from such at least one technician; and sending confirmation of end of work shift to such at least one technician. Further, it provides such an Internet-website-client-server-assisted system further comprising the step of presenting planned shift scheduling to such at least one technician. Even further, it provides such an Internet-website-client-server-assisted system further comprising the steps of: preparing text-based reports; and preparing graphical reports. In accordance with another preferred embodiment hereof, this invention provides an Internet website client-server computer system relating to providing on-location electronics troubleshooting services comprising, in combination: computer interface and storage means for registering customer data relating to at least one customer; computer interface and storage means for registering technician data relating to at least one technician having electronics-technician abilities relating to providing such on-location electronics troubleshooting services; database means for maintaining a database of such customer data relating to such at least one customer; database means for maintaining a database of such technician data relating to such at least one technician; computer processor means for managing collecting at least one fee from such at least one customer relating to such on-location electronics troubleshooting services; computer interface and storage means for receiving requests relating to such on-location electronics troubleshooting services from such at least one customer; computer processor and communications-device means for automatically notifying such at least one technician to provide such on-location electronics troubleshooting services requested by such at least one customer; and computer interface and storage means for recording on-location electronics troubleshooting service information. Moreover, it provides such an Internet website client-server computer system further comprising: computer processor means for substantially fully automating such dispatching of such at least one technician to such at least one customer relating to such on-location troubleshooting. Also, it provides such an Internet website client-server computer system further comprising: computer processing means for selecting such at least one technician using dispatch selection criteria; wherein such dispatch selection criteria comprises such at least one technician assigned to such same geographic dispatch area of such at least one customer requesting on-location electronics troubleshooting services, and such at least one technician having greatest elapsed time since last such dispatch; and communications device means for notifying such at least one technician to provide such on-location electronics troubleshooting services requested by such at least one customer; and computer processor means for recording time of such notification of such at least one technician. Additionally, it provides such an Internet website client-server computer system, wherein such computer processor means for managing collecting at least one fee from such at least one customer relating to such on-location electronics troubleshooting services further comprises: computer interface and storage means for receiving credit card account information from such at least one customer; computer processor and communications means for requesting payment from such at least one credit card account on behalf of such at least one customer; and computer processor means for recording such payment on behalf of such at least one customer. Also, it provides such an Internet-website-client-server-assisted system, wherein such computer processor and communications means for requesting payment from such at least one credit card account on behalf of such at least one customer comprises computer processor and communications means for requesting such at least one payment from such at least one credit card account on behalf of such at least one customer substantially automatically at pre-determined intervals. In addition, it provides such an Internet-website-client-server-assisted system, wherein such computer processor and communications means for requesting payment from such at least one credit card account on behalf of such at least one customer comprises computer processor and communications means for requesting such at least one payment from such at least one credit card account on behalf of such at least one customer at completion of on-location electronics troubleshooting services by such at least one technician. And, it provides such an Internet website client-server computer system, wherein such computer interface and storage means for receiving requests relating to such on-location electronics troubleshooting services from such at least one customer further comprises: computer interface means for inputting login identification information by such at least one customer; computer processing means for validating login identification information from such at least one customer; computer interface means for receiving confirmation of accuracy of such customer information; computer interface and storage means for receiving contact information relating to such current at least one on-location electronics troubleshooting request; and computer interface and storage means for receiving at least one problem description relating to such current at least one on-location electronics troubleshooting request by such at least one customer. Further, it provides such an Internet website client-server computer system, further comprising: computer interface and storage means for receiving at least one work shift start request from such at least one technician; computer interface means for presenting confirmation of start of work shift to such at least one technician; computer interface and storage means for receiving at least one end of work shift request from such at least one technician; computer interface means for presenting confirmation of end of work shift to such at least one technician; computer interface means for presenting planned shift scheduling to such at least one technician; computer interface and processor means for presenting text reports; and computer interface and processor means for presenting graphical reports. Even further, it provides such an Internet website client-server computer system, wherein such computer interface and storage means for recording on-location electronics troubleshooting service information further comprises: computer interface and storage means for receiving start time of such on-location electronics troubleshooting service from such selected at least one technician; computer interface and storage means for receiving end time of such on-location electronics troubleshooting services from such selected at least one technician; computer interface and storage means for receiving indication of any need relating to repair service from such selected at least one technician; computer interface and storage means for receiving indication of selected type of such repair service from such selected at least one technician; computer processor means for selecting such at least one repair service of such selected type of repair service; communications device means for notifying such selected at least one repair service to contact such at least one customer; and computer interface and storage means for receiving customer satisfaction evaluation. In accordance with another preferred embodiment hereof, this invention provides at least one network-client-server-assisted system, relating to assisting providing services to at least one customer, comprising the steps of: maintaining a database on such at least one network-client-server-assisted system of customer-assistance information relating to such at least one customer; receiving, on such at least one network-client-server-assisted system, requests relating to such services from such at least one customer; and notifying automatically, using such at least one network-client-server-assisted system, at least one service provider to provide such services requested by such at least one customer. Glossary of General Terms and Acronyms The following terms and acronyms explained below as background and are used throughout the detailed description: Client-Server. This term is sometimes used herein to refer to a model of interaction in a distributed system in which a program at one site sends a request to a program at another site and waits for a response. The requesting program is called the “client,” and the program, which responds to the request, is called the “server.” In the context of the World Wide Web, the “client” is often a “Web browser”, which runs on a user's computer; the program which responds to HTTP-based requests at a Website is commonly referred to as a “Web server.” Additionally, “Client” may be an executable program running on a user's computer which communicates with a “server” or “Web server” via the Internet or other networking methods using HTTP. Domain Name System (DNS). This term is sometimes used herein to refer to an Internet service that translates domain names (which are alphabetic identifiers) into IP addresses (which are numeric identifiers for machines on a TCP/IP network). File Transfer Protocol (FTP). This term is sometimes used herein to refer to the Internet standard high-level protocol for transferring files from one machine to another over TCP/IP networks. FTP is commonly used to download programs and other files to a computer from other servers. It is also used to transfer Web page files. Internet. This term is sometimes used herein to refer to a collection of interconnected (public and/or private) networks that are linked together by a set of standard protocols to form a distributed network. While this term is intended to refer to what is now commonly known as the Internet, it is also intended to encompass variations, which may be made in the future, including changes and additions to existing standard protocols. HyperText Markup Language (HTML). This term is sometimes used herein to refer to a standard coding convention and set of codes for attaching presentation and linking attributes to informational content within documents. During a document authoring stage, the HTML codes (referred to as “tags”) are embedded within the informational content of the document. When the Web document (or “HTML document”) is subsequently transferred from a Web server to a Web browser (or suitable executable program), the codes are interpreted by the Web browser (or suitable executable program) and used to parse and display the document. In addition to specifying how the Web browser (or suitable executable program) is to display the document, HTML tags can be used to create links to other websites and other Web documents (commonly referred to as “hyperlinks”). For more information on HTML, see Ian S. Graham, The HTML Source Book, John Wiley and Sons, Inc., 1995 (ISBN 0471-11894-4). HyperText Transport Protocol (HTTP). This term is sometimes used herein to refer to the standard World Wide Web client-server protocol used for the exchange of information (such as HTML documents, and client requests for such documents) between a Web browser or suitable executable program and a Web server. HTTP includes a number of different types of messages that can be sent from the client to the server to request different types of server actions. For example, a “GET” message, which has the format GET, causes the server to return the document or file located at the specified Universal Resource Locator (URL). LAN (Local Area Network)—This term is sometimes used herein to refer to a system that links together electronic office equipment, such as computers and word processors, and forms a network within an office or building. Transmission Control Protocol/Internet Protocol (TCP/IP). This term is sometimes used herein to refer to a standard Internet protocol (or set of protocols) which specifies how two computers exchange data over the Internet. TCP/IP handles issues such as packetization, packet addressing, and handshaking and error correction. For more information on TCP/IP, see Volumes I, II and III of Comer and Stevens, Internetworking with TCP/IP, Prentice Hall, Inc., ISBNs 0-13-468505-9 (vol. I), 0-13-125527-4 (vol. II), and 0-13-474222-2 (vol. III). Troubleshoot. This term is sometimes used herein to refer to a process of diagnosing and locating the source of a problem and taking corrective action up to, but not including repair. Troubleshooter. This term is sometimes used herein to refer to a person with appropriate skills who is capable of diagnosing and locating the source of a problem and taking corrective action up to, but not including repairs Uniform Resource Locator (URL). This term is sometimes used herein to refer to a unique address which fully specifies the location of a file or other resource on the Internet. The general format of a URL is protocol://machine address:port/path/filename. The port specification is optional, and if none is entered by the user, the Web browser (or suitable executable program) defaults to the standard port for whatever service is specified as the protocol. For example, if HTTP is specified as the protocol, the Web browser (or suitable executable program) will use the HTTP default port. The machine address in this example is the domain name for the computer or device on which the file is located. WAN (Wide Area Network)—This term is sometimes used herein to refer to a communications network that uses such devices as telephone lines, satellite dishes, or radio waves to span a larger geographic area than can be covered by a LAN. Work Cell. Used herein to refer generally to geographic areas that define the boundaries of service provided by technicians. Generally, work cell boundaries are set to ensure technicians can reach any customer within a predetermined time from dispatch. World Wide Web (“Web”). Used herein to refer generally to both (1) a distributed collection of interlinked, user-viewable hypertext documents (commonly referred to as “Web documents”, “Web pages”, “electronic pages” or “homepages”) that are accessible via the Internet, and (2) the client and server on-location services management software components that provide user access to such documents using standardized Internet protocols. Currently, the primary standard protocol for allowing applications to locate and acquire Web documents is the HyperText Transfer Protocol (HTTP), and the electronic pages are encoded using the HyperText Markup Language (HTML). However, the terms “World Wide Web” and “Web” are intended to encompass future markup languages and transport protocols that may be used in place of or in addition to the HyperText Markup Language and the HyperText Transfer Protocol. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic overview illustrating an example of the hardware architecture of the Internet. FIG. 2 is a schematic illustration of the typical communications between the on-location electronics troubleshooting services website components and on-location electronics troubleshooting services workstation components of various types of users, according to a preferred embodiment of the present invention. FIG. 3 is a schematic illustrating the customer sign up portion of a preferred on-location electronics troubleshooting services business method using an Internet website-based server system, according to a preferred embodiment of the present invention. FIG. 4 is a schematic illustrating the preferred on-location services portion of a preferred on-location electronics troubleshooting business method using an Internet website-based server system, according to a preferred embodiment of the present invention. FIG. 5 is a schematic illustrating preferred methods for technicians', supervisors', customers', others interactions with the on-location services management software, including changing customer billing information, technician and supervisor shift start and end and other similar activities. FIG. 6 presents an example of a preferred electronic display screen image illustrating the customer start screen for communicating with the website-based server of the on-location electronics troubleshooting services system, according to a preferred embodiment of the present invention. FIG. 7 illustrates an example of a preferred electronic display screen image illustrating the customer brief delay notice presented while a session for a customer is started on the website-based server of the on-location electronics troubleshooting services system, according to a preferred embodiment of the present invention. FIG. 8 illustrates an example of a preferred electronic display screen image showing how a customer may login to the on-location electronics troubleshooting services system, according to a preferred embodiment of the present invention. FIG. 9 presents a preferred electronic display screen image example illustrating the error message received by a customer who has attempted to login with an incorrect pin number, according to a preferred embodiment of the present invention. FIG. 10 illustrates a preferred electronic display screen image example of the message received when a customer cannot login or has forgotten a pin number, according to a preferred embodiment of the present invention. FIG. 11 is a preferred electronic display screen image example of a request by the on-location electronics troubleshooting services system for the customer to verify key contact information, according to a preferred embodiment of the present invention. FIG. 12 presents a preferred electronic display screen image example directing the customer to use the on-location electronics troubleshooting services system website to fix incorrect account information, according to a preferred embodiment of the present invention. FIG. 13 illustrates a preferred electronic display screen image of customer confirmation of contact information for a trouble call for the on-location electronics troubleshooting services system, according to a preferred embodiment of the present invention. FIG. 14 is a preferred electronic display screen image for customer entry of a description of the technical problem for which on-location electronics troubleshooting services are requested, according to a preferred embodiment of the present invention. FIG. 15 presents a preferred electronic display screen image of processing request notice presented to a customer after entry of a technical problem by the on-location electronics troubleshooting services system, according to a preferred embodiment of the present invention. FIG. 16 illustrates a preferred electronic display screen image notifying the customer their on-location electronics troubleshooting services request was not received, according to a preferred embodiment of the present invention. FIG. 17 illustrates a preferred electronic display screen image notifying the customer their on-location electronics troubleshooting services request was received and confirmation has been sent to their e-mail address. FIG. 18 presents a preferred electronic display screen image informing the customer that no connection to the Internet was found when a customer attempted to use the on-location electronics troubleshooting services system, according to a preferred embodiment of the present invention. FIG. 19 presents an example of a preferred electronic display screen image illustrating the technician start screen for communicating with the website-based server of the on-location electronics troubleshooting services system, according to a preferred embodiment of the present invention. FIG. 20 illustrates an example of a preferred electronic display screen image illustrating the technician brief delay notice presented while a session for a technician is started on the website-based server of the on-location electronics troubleshooting services system, according to a preferred embodiment of the present invention. FIG. 21 illustrates an example of a preferred electronic display screen image showing how a technician may login to the on-location electronics troubleshooting services system, according to a preferred embodiment of the present invention. FIG. 22 presents a preferred electronic display screen image example illustrating the error message received by a technician who has attempted to login with an incorrect technician ID number, according to a preferred embodiment of the present invention. FIG. 23 illustrates a preferred electronic display screen image example of the message received when a technician cannot login or has forgotten a technician ID number, according to a preferred embodiment of the present invention. FIG. 24 provides a preferred electronic display screen image illustrating the presentation of the technician work shift schedule and key contact information contained in the on-location electronics troubleshooting services system, according to a preferred embodiment of the present invention. FIG. 25 illustrates the preferred shift start confirmation message sent to the technician as an electronic display screen image after successfully “clocking in” to the on-location electronics troubleshooting services system, according to a preferred embodiment of the present invention. FIG. 26 presents a preferred electronic display screen image notifying the technician when an attempt to “clock out” was made without having “clocked in” to the on-location electronics troubleshooting services system, according to a preferred embodiment of the present invention. FIG. 27 presents a preferred electronic display screen image notifying the technician that an attempt to “clock in” to the on-location electronics troubleshooting services system prior to the start of a scheduled shift was made too early, according to a preferred embodiment of the present invention. FIG. 28 provides a preferred electronic display screen image notifying the technician that the “clock out” request to end the shift was successful, according to a preferred embodiment of the present invention. FIG. 29 presents a preferred electronic display screen image informing the technician that no connection to the Internet was found when a customer attempted to use the on-location electronics troubleshooting services system, according to a preferred embodiment of the present invention. FIG. 30 illustrates a preferred electronic display screen image notifying the technician that the technician's on-location electronics request transmission was not received, according to a preferred embodiment of the present invention. FIG. 31 presents an example of a preferred electronic display screen image illustrating the supervisor start screen for communicating with the website-based server of the on-location electronics troubleshooting services system, according to a preferred embodiment of the present invention. FIG. 32 illustrates an example of a preferred electronic display screen image illustrating the supervisor brief delay notice presented while a session for a supervisor is started on the website-based server of the on-location electronics troubleshooting services system, according to a preferred embodiment of the present invention. FIG. 33 illustrates an example of a preferred electronic display screen image showing how a supervisor may login to the on-location electronics troubleshooting services system, according to a preferred embodiment of the present invention. FIG. 34 presents a preferred electronic display screen image example illustrating the error message received by a supervisor who has attempted to login with an incorrect supervisor ID number, according to a preferred embodiment of the present invention. FIG. 35 illustrates a preferred electronic display screen image example of the message received when a supervisor cannot login or has forgotten a supervisor ID number, according to a preferred embodiment of the present invention. FIG. 36 illustrates the preferred shift start confirmation message sent to the supervisor as an electronic display screen image after successfully “clocking in” to the on-location electronics troubleshooting services system, according to a preferred embodiment of the present invention. FIG. 37 presents a preferred electronic display screen image notifying the supervisor when an attempt to “clock out” was made without having “clocked in” to the on-location electronics troubleshooting services system, according to a preferred embodiment of the present invention. FIG. 38 presents a preferred electronic display screen image notifying the supervisor that an attempt to “clock in” to the on-location electronics troubleshooting services system prior to the start of a scheduled shift was made too early, according to a preferred embodiment of the present invention. FIG. 39 provides a preferred electronic display screen image notifying the supervisor that the “clock out” request to end the shift was successful, according to a preferred embodiment of the present invention. FIG. 40 presents a preferred electronic display screen image informing the supervisor that no connection to the Internet was found when a supervisor attempted to use the on-location electronics troubleshooting services system, according to a preferred embodiment of the present invention. FIG. 41 illustrates a preferred electronic display screen image notifying the supervisor that the supervisor's on-location electronics request transmission was not received, according to a preferred embodiment of the present invention. FIG. 42 provides a preferred electronic display screen image illustrating the presentation to the supervisor of the technician work shift schedule and key contact information contained in the on-location electronics troubleshooting services system, according to a preferred embodiment of the present invention. FIG. 43 illustrates a preferred electronic display screen image of a supervisor's feedback report of on-location electronics troubleshooting services requests handled by technician in a specified work cell for a specified date range, according to a preferred embodiment of the present invention. FIG. 44 provides a preferred electronic display screen image of the screen used by the supervisor to modify the current work shift schedules contained in the on-location electronics troubleshooting services system, according to a preferred embodiment of the present invention. FIG. 45 illustrates a preferred electronic display screen image of the homepage which presents the initial user selection options for the on-location electronics troubleshooting services system website, according to a preferred embodiment of the present invention. FIG. 46 is an electronic display screen image of the preferred screen requesting contact information which is presented to users who selected the “Interested in Our Service?” text link on the website homepage, according to a preferred embodiment of the present invention. FIG. 47 presents a preferred electronic display screen presented to users interested in on-location electronics troubleshooting services after submitting contact information to the on-location electronics troubleshooting services system website, according to a preferred embodiment of the present invention. FIG. 48 provides a preferred electronic display screen image requesting customer phone number and PIN number which is presented to users who selected the “Customer Login” text link from the on-location electronics troubleshooting services system website homepage, according to a preferred embodiment of the present invention. FIG. 49 illustrates a preferred electronic display screen image presented to users when they have not entered a correct phone number or PIN number, according to a preferred embodiment of the present invention. FIG. 50 presents a preferred electronic display screen image displaying the preferred options available to customers after successfully logging in to the on-location electronics troubleshooting services system website, according to a preferred embodiment of the present invention. FIG. 51 provides an example of a preferred electronic display screen image thanking the customer for submitting comments regarding the on-location electronics troubleshooting services, according to a preferred embodiment of the present invention. FIG. 52 provides a preferred electronic display screen image requesting technician phone number and PIN number which is presented to users who selected the “Technician Login” text link from the on-location electronics troubleshooting services system website homepage, according to a preferred embodiment of the present invention. FIG. 53 illustrates a preferred electronic display screen image presented to a technician when the technician has not entered a correct phone number or PIN number, according to a preferred embodiment of the present invention. FIG. 54 presents a preferred electronic display screen image displaying the preferred options available to technicians after successfully logging in to the on-location electronics troubleshooting services system website, according to a preferred embodiment of the present invention. FIG. 55 is an illustration of a preferred electronic display screen image for completing a work order presented to a technician who chose the “Complete Work Order” text link from technician options screen, according to a preferred embodiment of the present invention. FIG. 56 provides a preferred electronic display screen image used to notify a technician that an incorrect work order number was entered when attempting to complete a work order and to request reentry of the work order number and other requested information, according to a preferred embodiment of the present invention. FIG. 57 illustrates a preferred electronic display screen image presented to a technician after successfully completing a work order and indicating the customer requires a contractor for further repairs, according to a preferred embodiment of the present invention. FIG. 58 provides an illustration of a preferred electronic display screen image presented to the technician/customer after successfully completing a work order which requests that customers preferably provide an indication of their level of satisfaction, according to a preferred embodiment of the present invention. FIG. 59 provides a preferred electronic display screen image used to notify a customer that an incorrect customer PIN number was entered when attempting to indicate level of satisfaction with a technician's work a work order and to request reentry of the customer PIN number and level of satisfaction, according to a preferred embodiment of the present invention. FIG. 60 provides an example of a preferred electronic display screen image thanking customers for using on-location electronics troubleshooting services which is presented after successfully providing an indication of their level of satisfaction, according to a preferred embodiment of the present invention. FIG. 61 is a preferred electronic display screen image requesting a customer's contact and credit card information which is presented after a technician has selected the “Initial Customer Setup” text link on the electronic display screen image presented in FIG. 54, according to a preferred embodiment of the present invention. FIG. 62 illustrates a preferred electronic display screen image presented to a technician after successful entry of a customer's contact and credit card information which allows the technician to set up the required customer interface software download to the customer's personal computer, according to a preferred embodiment of the present invention. FIG. 63 presents an illustration of a preferred electronic display screen image requesting that the customer's contact and credit card information be re-entered because the credit card was not accepted on the first entry, according to a preferred embodiment of the present invention. FIG. 64 is an electronic display screen image of the preferred screen requesting contact and low voltage background information which is presented to users who selected the “Interested in becoming a Systemsecure technician?” text link on the website homepage, according to a preferred embodiment of the present invention. FIG. 65 provides a preferred electronic display screen image requesting supervisor phone number and PIN number which is presented to users who selected the “Supervisor Login” text link from the on-location electronics troubleshooting services system website homepage, according to a preferred embodiment of the present invention. FIG. 66 illustrates a preferred electronic display screen image presented to supervisors who have not entered a correct phone number or PIN number, according to a preferred embodiment of the present invention. FIG. 67 is a preferred electronic display screen image requesting a technician's contact information which is presented after a supervisor has successfully logged in to the on-location electronics troubleshooting services system website, according to a preferred embodiment of the present invention. FIG. 68 illustrates a preferred electronic display screen image presented to a supervisor after successful entry of a technician's contact information which allows the technician to set up the required technician interface software download to the technician's personal computer, according to a preferred embodiment of the present invention. FIG. 69 presents a preferred electronic display screen image, which is displayed when a customer selects the “Modify billing info” text link on the electronic display screen image presented in FIG. 50 and which allows a customer to modify customer contact and credit card information, according to a preferred embodiment of the present invention. FIG. 70 provides an illustration of a preferred electronic display screen image presented to customers after successfully changing contact and credit card information, according to a preferred embodiment of the present invention. FIG. 71 is a schematic illustrating a preferred alternate on-location electronics troubleshooting services business method using telephones in combination with an Internet website-based server system for selected functions, according to a preferred embodiment of the present invention. FIG. 72 is a schematic illustrating a preferred electronics supplier sales partnering business method, according to a preferred embodiment of the present invention. FIG. 73 is a schematic illustrating a services business method using an Internet website-based server system, according to an alternate preferred embodiment of the present invention. FIG. 74 is a schematic illustrating an overview of how the invention may, under appropriate circumstances, suffice to provide a variety of benefits and be implemented to solve many different problems, according to an alternate preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE BEST MODES AND AND PREFERRED EMBODIMENTS OF THE INVENTION Referring now to FIG. 1, a schematic overview of a preferred embodiment of the present invention on the Internet is shown. The present invention preferably comprises a web server 101. The web server 101 comprises input and output devices as is well known in the art. For example, the web server 101 preferably comprises a central processing unit (CPU) 108, a display screen or monitor 102, a keyboard 104, a printer 106, a mouse 105, etc. The web server 101 further preferably comprises a database 103 for storage of the data and software comprising preferred embodiments of the present invention. The web server 101 is preferably connected to the Internet 107 that serves as the presently preferred communications medium. The Internet 107 comprises a global network of networks and computers, public and private. The Internet 107 is the preferable connection method to the users' workstations 109, 110, 111 and nnn in preferred embodiments of the present invention. The CPU 108 executes program code stored in one or more of ROM, RAM and mass storage devices to carry out the functions and acts described in connection with the web server 101. The CPU 108 comprises at least one conventional high-speed digital microprocessor such as an Intel Pentium processor, electrically coupled to each of the other components of the web server 101, adequate to execute program modules for all application functions including, but not limited to executing customer login, technician login, supervisor login, interaction with customer, technician and supervisor local software, supervisor and manager reporting processes, communicating with the banking system, selected electronics suppliers, electronics repair contractors and at least one telephone interface system. The CPU 108 interacts with ROM, RAM and the mass storage device to execute stored program code according to conventional data processing techniques. According to one embodiment of the invention, as shown in FIG. 1, each user workstation device 109, 110, 111 and nnn is a browser based system implemented as a single interactive visual display device, audio device or other like interactive device such as a general purpose computer, a personal digital assistance (PDA), phone, or interactive television system. There are many commercial software programs that can enable the communications required by the consumer workstations with the Web Server 101, the primary function being transmission and reception of data through the Internet and presentation of data to the consumer. Examples of such software programs include the Netscape Navigator browser by Netscape Corporation and the Internet Explorer browser by Microsoft Corporation. Each user workstation 109, 110, 111 and nnn (collectively nodes) is capable of communicating directly and indirectly with the Web Server 101. Communication between each node 109, 110, 111 and nnn and the web server 101 is electronic by means of known communication protocols, such as TCP/IP, and is capable of decrypting and encrypting data received and transmitted between nodes 109, 110, 111 and nnn. Each node 109, 110, 111 and nnn may be connected directly or indirectly to the website server 101 via a connection to a network, such as a local area network (LAN), a wide area network (WAN), the Internet 107 or the like, via a public switched phone network, dedicated data line, cellular network, Personal Communication System, microwave, satellite networks, cable or the like. In a preferred embodiment shown in FIG. 1 the web server 101 is implemented as a single general purpose computer. In another preferred embodiment, the functionality of the web server 101 is distributed over a plurality of computers. In that preferred embodiment, the web server 101 is configured in a distributed architecture, wherein the databases and processors are housed in separate units or locations and connected via a network connection such as those discussed above. Those skilled in the art will appreciate that an almost unlimited number of processors may be supported. This arrangement yields a more dynamic and flexible system, less prone to catastrophic hardware failures affecting the entire system. Although the illustrated overview is one preferred embodiment, one skilled in the art will appreciate that, under appropriate circumstances, various sections may be omitted, rearranged or adapted in various ways for various purposes. Referring now to FIG. 2, it presents a schematic overview of the preferred functional modules of the present invention. Preferably, the Web Server 101 and its underlying on-location services management software provide all the services requested or required for each of the other functions. Preferably, the underlying on-location services management software is constructed using available software development languages such as Java, Visual Basic and the like. The database management preferably utilizes commercially available products such as Oracle, Microsoft SQL Server and the like. Preferably, the Website Interface software 201 provides access to the web site through a connection to the Internet 107 to perform a variety of functions at the request of users. Preferably, it allows existing customers 303 to login to the on-location services management software on the Web Server 101 and make changes to their customer information including credit card billing information. Additionally, customers 303 may preferably request that on-location electronics troubleshooting services be provided at an additional location, move the existing services to another location, install the user interface software on another computer or make a comment. Preferably, it also provides the capability for users interested in on-location electronics troubleshooting services to request they be contacted. Preferably, it also provides the opportunity for technicians 304 to login to the on-location services management software operating on the Web Server 101 for initial customer setup and customer interface software 202 download, to record completion of work orders and to assist customers 303 in the completion of a satisfaction survey. Additionally, it preferably provides a means for supervisors to login to the on-location services management software operating on the Web Server 101 to assist new technicians 304 in initial setup and technician interface software 207 download to the technician's personal computer. Also, it preferably provides the capability for technicians 304 interested in providing on-location electronics troubleshooting services to apply for employment. Preferably, the Customer Interface software 202 has been downloaded from the Web Server 101 to the personal computer belonging to the customer 303 for use by an existing customer 303 to preferably request that on-location electronics troubleshooting services be performed. A request for services from a customer 303 and subsequent responses are preferably transmitted via the Internet 107 to the on-location services management software operating on the Web Server 101. The Electronics Suppliers' Web Server 203 preferably may be accessed from the on-location services management software operating on the Web Server 101 by a customer 303 via a link via the Internet 107 for the purpose of purchasing a product from the electronics supplier. The Supervisor Interface software 204 is preferably a downloaded software program resident on a supervisor's personal computer which preferably communicates with the on-location services management software operating on the Web Server 101 via the Internet 107. The Supervisor Interface software 204 preferably permits a supervisor to login to the on-location services management software operating on the Web Server 101 and perform a variety of tasks preferably including recording the beginning and ending times of a shift, viewing and creating and modifying technician work schedule and contact information, and viewing reports of on-location electronics troubleshooting services performed. The Owner/Manager Interface software 205 is preferably a downloaded software program resident on an owner/manager's personal computer which preferably communicates with the on-location services management software operating on the Web Server 101 via the Internet 107. The Owner/Manager Interface 205 preferably permits an owner/manager to login to the on-location services management software operating on the Web Server 101 and perform a variety of tasks preferably including viewing technician work schedules and contact information, viewing a variety of reports including on-location electronics troubleshooting services performed and customer satisfaction reports. Preferably, the Banking System 206 communicates the on-location services management software operating on the Web Server 101 via the Internet 107 to verify customer credit card information and accept credit card transactions presented for collection by the on-location services management software on the Web Server 101. The Technician Interface software 207 is preferably a downloaded software program resident on a personal computer belonging to a technician 304 which preferably communicates with the on-location services management software operating on the Web Server 101 via the Internet 107. The Technician Interface 207 preferably permits a technician 304 to login to the on-location services management software operating on the Web Server 101 and perform a variety of tasks preferably including recording the beginning and ending times of a shift and viewing technician work schedules. The Telephone 208 (which may be a standard corded or wireless telephone or a standard cellular telephone) and telephone interface preferably work in concert to provide an alternative method for customers 303 to request on-location electronics troubleshooting services. Additionally, the Telephone 208 and telephone interface 209 preferably provide an alternative method for technicians 304 and supervisors 302 to record the beginning and ending times of a shift. Preferably, on-location services management software on the Web Server 101 periodically queries telephone interface 209 for messages via the Internet 107. Preferably, when messages are presented they are removed from telephone interface 209 and processed by on-location services management software on the Web Server 101 to complete the actions requested by customers 303, technicians 304 and supervisors 302. Preferably, email messages are sent to Repair Companies 210 via the Internet 107 by the on-location services management software on the Web Server 101 whenever it has been determined that a customer 303 requires a repair and a technician 304 has entered the information via the Website Interface 201. The email message is sent to a selected repair company which will preferably contact the customer 303 to schedule the required services. Preferably, technicians 304 are dispatched using text messaging and paging 211 performed directly by the on-location services management software operating on the Web Server 101. Although the illustrated overview is one preferred embodiment, one skilled in the art, upon reading this specification, will appreciate that, under appropriate circumstances, various sections may be omitted, rearranged or adapted in various ways for various purposes. According to a preferred embodiment of the present invention, preferably a combination of on-location services management software and Internet services are utilized to manage and dispatch technicians 304 to troubleshoot reported problems with low-voltage electronics in homes and small businesses at any time of day, any day of the week, and any day of the year. A preferred goal is for the technician 304 to arrive on-location within a timeframe of less than one hour from the time of receipt of the request for on-location electronics troubleshooting services. Preferably, to accomplish a rapid response to customer requests for troubleshooting assistance, work cells will be defined which preferably include an appropriate number of technicians 304 and customers 303. In addition, technicians 304 are assigned to work cells on the basis of their residence; preferably technicians 304 who live within a given work cell are assigned to that work cell. Under appropriate circumstances, technicians 304 may be assigned to work cells which do not include their residence. Preferably, technicians 304 are automatically dispatched to the location of customer 303 using pager text messages generated from the entered and stored information by the customer 303, such as contact name and address and telephone numbers. Preferably, technician dispatch is automatically performed using an algorithm which considers the time of the last dispatch for each technician 304 assigned to a work cell and dispatches the technician 304 with the longest time since the last dispatch. Referring now to FIG. 3, a schematic overview of a preferred embodiment of the primary business elements of the present invention is shown. In a preferred embodiment of the present invention, in the initial contact step 311 a customer 303 learns of the on-location electronics troubleshooting services from advertising and other marketing activities and preferably expresses an interest in the services through the Web Site Home Page, FIG. 45, Interested in Our Service screen, FIG. 46, and the Thanks, You will be contacted screen, FIG. 47. Preferably, in customer contact step 321 the Owner/Manager 301 contacts the customer 303 using one or more typical methods and preferably the customer 303 agrees to subscribe to the on-location electronics troubleshooting services for a period of at least one year and preferably to pay the agreed monthly fee via an automatic monthly charge to a credit card belonging to the customer 303. In a preferred embodiment of the present invention, as illustrated by the technician 304 dispatch step 322, once a potential customer 303 has agreed to subscribe to the on-location electronics troubleshooting services, a technician 304 will be dispatched to the home or place of business of the potential customer 303. Preferably, once the technician 304 is at the service location of customer 303, he or she will complete the customer sign up step 322 by logging on to the on-location services management software operating on the Web Server 101, as shown in FIG. 45, FIG. 52, FIG. 53 and FIG. 54; and the customer 303 will preferably enter his or her name and address and contact information and credit card information, as illustrated in FIG. 61 and FIG. 62 (embodying herein computer interface and storage means for registering customer data for at least one customer). After entry and acceptance of the credit card information, the customer information is stored in the database (embodying herein database means for maintaining a database of such customer data for such at least one customer and embodying herein computer interface and storage means for receiving credit card account information from such at least one customer) and the customer interface software 202 is downloaded from the Web Server 101 and installed on a personal computer which is, or can be, connected to the Internet 107, as shown in FIG. 3. Preferably, the technician 304 instructs the customer 303 on the usage of the customer interface software 202. Referring again to FIG. 3, in the “arrange for credit card processing” step 351, the owner/manager 301 will preferably conclude an agreement with appropriate credit card processing companies 305 to permit verification of credit cards of customer 303; and then the processing may begin of credit card payment requests and automatic deposit of the payments to a specified bank account on behalf of the owner/manager 301. In the request payment step 352, on completion of a service request preferably the on-location services management software will preferably create a payment request for the customer 303 and transmit it to the credit card processing company 305 for payment to the owner/manager 301. Alternatively, in the request payment step 352, each month the on-location services management software will preferably automatically create a payment request for each customer 303 and transmit it to the credit card processing company 305 for payment to the owner/manager 301. In the receive payments step 353 the owner/manager 301 preferably receives the customer 303 payments (embodying herein computer processor means for managing collecting at least one fee from such at least one customer relating to such on-location electronics troubleshooting services; and embodying herein computer processor and communications means for requesting payment from such at least one credit card account on behalf of such at least one customer; and embodying herein computer processor means for recording such payment on behalf of such at least one customer; and embodying herein computer processor and communications means for requesting payment from such at least one credit card account on behalf of such at least one customer comprises computer processor and communications means for requesting such at least one payment from such at least one credit card account on behalf of such at least one customer at completion of on-location electronics troubleshooting services by such at least one technician; and embodying herein computer processor and communications means for requesting such at least one payment from such at least one credit card account on behalf of such at least one customer substantially automatically at pre-determined intervals). Referring now to FIG. 4, in a preferred embodiment of the present invention, the first step of providing on-location support is illustrated by the services request step 421 in which a customer 303, preferably using the customer interface software 202, logs in to the on-location services management software operating on the Web Server 101 using his or her customer ID number (embodying herein computer interface means for inputting login identification information by such at least one customer) and preferably completes a request for on-location assistance. The preferred login software interactions between the customer 303 and the customer interface software 202 are presented in FIG. 6, FIG. 7, FIG. 8, FIG. 9 FIG. 10, FIG. 11 and FIG. 12. The preferred assistance request interactions between the customer 303 and the customer interface software 202 are illustrated in FIG. 13, FIG. 14, FIG. 15, FIG. 16, FIG. 17, and FIG. 18 (embodying herein computer interface and storage means for receiving requests relating to such on-location electronics troubleshooting services from such at least one customer). Referring further to FIG. 4, in the technician dispatch step 422 preferably a technician 304 is selected from the technicians 304 assigned to the work cell in which the customer 303 is located and is preferably dispatched by on-location services management software running on the Web Server 101. Preferably, the on-location services management software considers the elapsed time since the last dispatch for each available technician 304 (embodying herein computer processing means for selecting such at least one technician using dispatch selection criteria) and automatically selects the technician 304 with the longest period since the last dispatch (embodying herein wherein such dispatch selection criteria comprises such at least one technician assigned to such same geographic dispatch area of such at least one customer requesting on-location electronics troubleshooting services, and such at least one technician having greatest elapsed time since last such dispatch). Preferably, after selecting an available technician 304 the on-location services management software sends an alpha/numeric page to the selected technician 304 and records the time the page was sent to the technician 304 in the database with the original service request from the customer 303 (embodying herein computer processor means for substantially fully automating such dispatching of such at least one technician to such at least one customer relating to such on-location troubleshooting; and embodying herein computer processor means for recording time of such notification of such at least one technician). The alphanumeric page preferably provides the necessary information, including contact name, contact phone number and location address, for the technician 304 to contact the customer 303 (embodying herein computer processor and communications-device means for automatically notifying such at least one technician to provide such on-location electronics troubleshooting services requested by such at least one customer; and embodying herein communications device means for notifying such at least one technician to provide such on-location electronics troubleshooting services requested by such at least one customer). Preferably, on receipt of the pager message the technician 304 will call the customer 303 and provide an estimated time of arrival. Referring to FIG. 4 again, preferably the step of problem resolution 423 begins with the arrival of the technician 304 at the service location of the customer 303 who requested the troubleshooting service. On arrival, the technician 304 will preferably evaluate the problem reported by the customer 303 and make any necessary adjustments, changes in settings and parameters and, in general, preferably do all that is possible to solve the reported problem without making an internal repair to the problem low-voltage equipment. If the technician 304 cannot resolve the reported problem preferably the customer 303 is advised to arrange for a repair to the problem low-voltage equipment. Preferably, as the final part of the problem resolution step 423, at the completion of troubleshooting the technician 304 will preferably use a personal computer at the customer 303 location to close the troubleshooting request. Preferably, the technician 304 will login to the on-location services management software on the Web Server 101 as shown in FIG. 45, FIG. 52, FIG. 53 and FIG. 54. After successfully logging in, the technician 304 preferably reports the start and completion times of the troubleshooting effort (embodying herein computer interface and storage means for receiving start time of such on-location electronics troubleshooting service from selected such at least one technician; and embodying herein computer interface and storage means for receiving end time of such on-location electronics troubleshooting services from selected such at least one technician) and if necessary, requests repair service specifying the type of repair service needed and submits the information to be stored in the on-location services management software database (embodying herein computer interface and storage means for recording on-location electronics troubleshooting service information; and embodying herein computer interface and storage means for receiving of any need relating to repair service from such selected at least one technician; and embodying herein computer interface and storage means for receiving indication of selected type of such repair service from such selected at least one technician; and embodying herein computer processor means for selecting such at least one repair service of such selected type of repair service). Then the technician 304 requests that the customer 303 indicate his or her level of satisfaction with the service as illustrated in FIG. 55, FIG. 56, FIG. 57, FIG. 58, FIG. 59 and FIG. 60 (embodying herein computer interface and storage means for receiving customer satisfaction evaluation). If the customer 303 has indicated dissatisfaction with the service provided the on-location services management software on the Web Server 101 will initiate an alpha/numeric page to the supervisor 302, as shown in supervisor notice step 441, who will preferably take necessary actions to resolve the customer 303 dissatisfaction. Further, if the technician 304 has indicated the need for a repair to the problem low-voltage equipment, the on-location services management software on the Web Server 101 will generate an email notice to a number of selected repair companies 306, as shown in repair company notice step 424. Preferably, the on-location services management software on the Web Server 101 selects a pre-determined number of repair companies 306 from a pre-qualified list of companies that specialize in the type of repairs required by the customer 303 (embodying herein communications device means for notifying such selected at least one repair service to contact such at least one customer). After receiving the email notice, preferably a selected number of repair companies 306 will contact the customer 303 directly and arrange the repairs and subsequent payment by the customer 303 to the repair company 306 as shown in the equipment repairs step 425. Referring again to FIG. 4, as illustrated by “arrange repair services” step 461, the owner/manager 301 preferably identifies repair companies 306 which can provide repairs for customers 303. Preferably, the owner/manager 301 will evaluate skill and quality of service of each candidate repair company 306, selecting only those which meet the standards of the owner/manager 301. Preferably, each selected repair company 306 will complete an agreement to meet the required standards of service and provide a commission to the owner/manager 301 for each completed repair. In the repair service set up step 471, the owner/manager 301 will load each repair company 306 with which the owner/manager 301 has completed an agreement. In the commission payment step 462, preferably each repair company 306 will pay the owner/manager 301 a commission based on the number and amount of each completed repair on an agreed schedule. Referring to FIG. 4, after completion of the requested repairs the customer 303 will be given the opportunity to report completion of the repairs and in return be eligible to receive a portion of the commission paid by the repair company 306 to the owner/manager 301. Referring to FIG. 5, in the customer update step 521, preferably the customer 303 can login to the on-location services management software on the Web Server 101 to update billing and contact information, request addition of service for an additional location, request moving the service to a different location, request installation of the customer interface software 202 on a different personal computer. These activities are illustrated in FIG. 45, FIG. 48, FIG. 49, FIG. 50, FIG. 69 and FIG. 70. Additionally, a customer 303 can preferably provide additional feedback or comments as illustrated in FIG. 51. Additionally, as shown in FIG. 5, a technician 304 may apply to work for/with the owner/manager 301 in technician application step 531. This activity is illustrated by the screens shown in FIG. 45 and FIG. 64. After acceptance of a technician 304 to work with/for the owner/manager 301 a supervisor 302 will go to the residence of the technician 304 to set up the technician interface software 207 on a personal computer which is capable of being connected to the Internet 107, as shown in technician set up step 541. Preferably, the supervisor 302 will login to the on-location services management software on the Web Server 101 using a typical browser as shown in FIG. 45, FIG. 65 and FIG. 66. After successfully logging in, the supervisor 302 accesses the Create Employee Account screen, as shown in FIG. 67, and preferably enters all the requested information (embodying herein computer interface and storage means for registering technician data relating to at least one technician having electronics-technician abilities relating to providing such on-location electronics troubleshooting services). After completing the Create Employee Account screen, the technician information is saved to the database (embodying herein database means for maintaining a database of such technician data relating to such at least one technician). The supervisor will preferably use the Download Employee Software screen, as shown in FIG. 68, to download the Technician Interface software 207 from the Web Server 101 and install it on the personal computer belonging to the technician 304. Further, as shown in FIG. 5, the technician schedule step 532 preferably includes several technician 304 activities. First each technician 304 will login through the technician interface software 207 as illustrated by the screens shown FIG. 31, FIG. 32, FIG. 33, FIG. 34, FIG. 35, FIG. 40 and FIG. 41. Upon a successful login, preferably each technician 304 will indicate either the start or end time of his or her shift, as shown in the screen examples illustrated in FIG. 25, FIG. 26, FIG. 27 and FIG. 28. Preferably, by indicating the shift start time makes a technician 304 available to receive dispatch messages from the on-location services management software on the Web Server 101. Likewise, indicating the shift end time makes the technician 304 unavailable for dispatch messages. After a successful login, the technician 304 may also query the on-location services management software on the Web Server 101 for the current schedule and technician 304 contact information, as shown in the screen example shown in FIG. 24. Once again, referring to FIG. 5, preferably the supervisor 302 uses the supervisor interface software 204 to complete several actions as part of supervisor schedule step 542. The supervisor 302 preferably logs in the on-location services management software on the Web Server 101 using the Supervisor Interface software 204 installed on his or her personal computer. The screens used for login are shown in FIG. 31, FIG. 32, FIG. 33, FIG. 34, FIG. 35, FIG. 40 and FIG. 41. Preferably, upon a successful login, each supervisor 302 will indicate either the start or end time of his or her shift, as shown in the screen examples illustrated in FIG. 36, FIG. 37, FIG. 38 and FIG. 39. Preferably, by indicating the shift start time makes a supervisor 302 available to receive messages from the on-location services management software on the Web Server 101. Likewise, indicating the shift end time makes the supervisor 302 unavailable for messages. After a successful login, the supervisor 302 may also query the on-location services management software on the Web Server 101 for the current schedule and supervisor 302 and technician 304 contact information, as shown in the screen example shown in FIG. 42. Additionally, a supervisor 302 may elect to view a report of on-location electronics troubleshooting services provided by technicians 304, as shown in FIG. 43 or to add/remove or edit technician 304 schedules, as shown in FIG. 44. Referring to FIG. 5, preferably the owner/manager 301 will login to the on-location services management software on the Web Server 101 to perform a variety of management and administrative activities as part of the owner/manager management step 511. The activities may preferably include queries and reports of on-location electronics troubleshooting services rendered, supervisor 302 and technician 304 schedules, reports of dissatisfied customers 303 and other actions as may be required. Examples of some preferred reports, which preferably may be any type of graph or text report and which can be saved, emailed and or printed, are: Average time it takes for a technician 304 to call back a customer 303 from the time the technician 304 received a work order request, Average time it takes for a technician 304 to arrive and start at the location of a customer 303 from the time the technician 304 received the work order, Average time it takes for a technician 304 to end at the location of customer 303 location after performing the service from the time the technician 304 received the work order, Average service cost per visit, Average time it takes for a technician 304 to start at the location of a customer 303 from the time the technician 304 called back the customer 303 to let them know help is on the way or that they have received the call from the customer 303, Average time it takes for a technician 304 to end at the location of a customer 303 from the time the technician 304 called back the customer 303 to let them know help is on the way or that they have received the call from the customer 303, Average time it takes for a technician 304 to complete a service visit, Average errors in attempting to process the credit card belonging to the customer 303 per given period of time or per quantity signed, Average times a customer 303 needed to change their credit card on the website because when service was completed, their credit card was denied per given period of time or per quantity signed up, Total or average amount of service requests per amount of people signed up or per given period of time, Average amount of calls in which the customer 303 would prefer to have the dispatcher at a given company dispatch their work request, instead of the customer 303 doing it, Average amount of times a customer 303 prefers that a specific technician 304 receive their work per number signed up or per given period of time, Average amount of times, the customer 303 needs service and wants to be added to the system, so they can do it themselves next time per number signed up or per given period of time, Average amount of times, the customer 303 needs service and does not want to be added to the system per number signed up or per given period of time, Total or average amount of service requests per amount of employees, Total or average amount of service requests per given amount of time, Total or average amount of hours spent by any given internal group or multiple groups within a company maintaining the company (company's own internal operations) or outside the company per number signed up or per given period of time, Total and average start times for employees per number signed up or per given period of time, Total and average end times for employees per number signed up or per given period of time, Reports depicting tasks with internal tracking numbers, start times, end times, outstanding problems, how a day could have been more productive, and comments for employees over time or a specified period of time, Graphs showing % time spent per given internal tracking number for an employee or multiple employees over time or a specified period of time, Reports depicting tasks, start times, end times and comments over time or a specified period of time, and Graphs showing % time spent per given task over time or a specified period of time (embodying herein computer interface and processor means for presenting text reports; and computer interface and processor means for presenting graphical reports). As described above, each of the activities of customer 303 are facilitated by particular on-location services management software capabilities. The following screens and interrelationships describe a preferred embodiment of the customer interface software 202. Referring to FIG. 6, Customer Start Screen, the customer 303 preferably may select the text link which opens a browser which preferably displays the website or selects the Close button to close the entire application. Preferably, selecting the 24 Hour Help button will display the Note screen, FIG. 7. Referring to FIG. 7, Note screen the customer 303 must select the OK button to continue the login process. Preferably, after this button is clicked the dialog closes and the program checks to see if the personal computer belonging to the customer 303 is connected to the Internet. If the personal computer is connected to the Internet then preferably the Customer ID Login screen, as illustrated in FIG. 8, will display. If the personal computer is not connected to the Internet then Error: Internet Connection screen, FIG. 18, will preferably display. Referring to FIG. 8, Customer ID Login screen, preferably a customer 303 must type in his or her personal customer ID number and click the OK button to successfully login (embodying herein computer interface means for inputting login identification information by such at least one customer). The program then preferably sends this request to the server and waits for a reply for a specified period of time. During this time a progress bar preferably continually updates. If the program does not receive the reply within the specified period of time, then the Error: Request Not Received screen, as illustrated in FIG. 16, is preferably presented. If the reply is received within the specified period of time and the customer ID number was entered incorrectly then preferably the Error: Login Failed screen, as shown in FIG. 9, is displayed (embodying herein computer processing means for validating login identification information from such at least one customer). If the customer 303 selects the Cancel button on the Login screen, FIG. 8, preferably all dialogs are closed and the Customer Start Screen, FIG. 6, is displayed. Referring to FIG. 9, Error: Login Failed screen, preferably a customer 303 must type in his or her personal customer ID number again and click the OK button to successfully login. The program then preferably sends this request to the server and waits for a reply for a specified period of time. During this time a progress bar preferably continually updates. If the program does not receive the reply within the specified period of time then the Error: Request Not Received screen, as illustrated in FIG. 16, is preferably presented. If the reply is received within the specified period of time and the customer ID number is incorrect then FIG. 9, the Error: Login Failed screen, is displayed again one last time. After the second incorrect customer ID number in this dialog, preferably the Notification screen, FIG. 10, is displayed telling the customer 303 their customer ID number will be emailed. If the reply is received within the specified period of time and the customer ID number was entered correctly then preferably FIG. 11, the Confirm Account Information screen, will display. Referring again to FIG. 9, preferably customer 303 may optionally click the Forgot Password button which will display the Notification Screen as shown in FIG. 10 to receive the appropriate pin number by email. Referring to FIG. 10, the Notification screen, upon presentation of this screen, preferably the customer 303 may only select the OK button which will preferably close all dialogs and return the customer 303 to the Customer Start screen, FIG. 6. Referring to FIG. 11, the Confirm Account Information screen, the customer 303 may preferably select the either the Correct button which will preferably display the Contact Information screen, FIG. 13, or the Incorrect button which will preferably present the Incorrect Account Information screen, FIG. 12 (embodying herein computer interface means for receiving confirmation of accuracy of such customer information). Referring to FIG. 12, the Incorrect Account Information screen, the customer 303 may preferably select either the Close button which closes all dialogs and displays the Customer Start Screen, FIG. 6, or select the text link which will preferably launch a browser window bringing the customer 303 to the website to update the account information. Referring to FIG. 13, the Contact Information screen, preferably the customer 303 may enter a name, select a phone number, and select the ‘OK’ button (embodying herein computer interface and storage means for receiving contact information relating to such current at least one on-location electronics troubleshooting request) which will display the Explain Problem screen, FIG. 14; or the customer 303 may select the Cancel button, which will preferable close all dialogs and display the Customer Start Screen, FIG. 6. Referring to FIG. 14, the Explain Problem screen, the customer 303 may preferably enter a description of the problem in the available text box (embodying herein computer interface and storage means for receiving problem description relating to such current at least one on-location electronics troubleshooting request by such at least one customer) and select the ‘Next’ button which will preferably present the Process Request screen FIG. 15, or may select the Cancel button which will preferably close all dialogs and display the Customer Start Screen, FIG. 6. Referring to FIG. 15, Process Request, the customer 303 may preferably select the ‘OK’ button to send the request to the server and continually wait for a reply for a specified period of time. During this time the progress bar continually updates. If a reply is not received within the specified period of time, then preferably the Error: Request Not Received screen, FIG. 16, is displayed. If a reply is received within the specified period of time, the request has been received and stored in the database (embodying herein computer interface and storage means for receiving requests relating to such on-location electronics troubleshooting services from such, at least one customer), then preferably the Confirmation screen, FIG. 17, is presented to the customer 303. Alternatively, the customer 303 may select the Cancel button which will preferably close all dialogs and display the Customer Start Screen, FIG. 6. Referring to FIG. 16, Error: Request Not Received screen, the customer 303 preferably may only select the OK button which preferably closes all dialogs and FIG. 6, the Customer Start screen is displayed. Referring to FIG. 17, the Confirmation screen, preferably customer 303 may only select the OK button which preferably closes all dialogs and FIG. 6, and the Customer Start screen is displayed. Referring to FIG. 18, the Error: Internet Connection screen, preferably the customer 303 may only select the OK button which preferably closes all dialogs and FIG. 6, and the Customer Start screen is displayed. As described above, each of the activities of technician 304 are facilitated by particular on-location services management software capabilities. The following screens and interrelationships describe a preferred embodiment of the technician interface software 207. Referring to FIG. 19, the Technician Start screen, the technician 304 has five options when initiating access to the system. Selecting the text link will preferably launch a browser window bringing the technician 304 to the website. Selecting the Clock In button, the Clock Out button or the View (Work Schedule/Contact Information) button preferably will pop up the Note screen, as shown in FIG. 20 (embodying herein computer interface and storage means for receiving at least one work shift start request from such at least one technician). Selecting the Close button will preferably close the entire application. Referring to FIG. 20, the Note screen, the technician 304 must select the OK button to continue the login process. After this button is clicked, the dialog closes and the program checks to see if the personal computer belonging to the technician 304 is connected to the Internet. If the personal computer is connected to the Internet, then preferably the Login screen, as illustrated in FIG. 21 will pop up. If the personal computer belonging to the technician 304 is not connected to the Internet, then preferably the Error: Internet Connection screen, as shown in FIG. 29, will pop up. Referring to FIG. 21, Technician Login ID, preferably a technician 304 must type in his or her personal technician ID number and click the OK button to successfully login. The program then preferably sends this request to the server and waits for a reply for a specified period of time. During this time a progress bar preferably continually updates. If the program does not receive the reply within the specified period of time then the Error: Request Not Received screen, as illustrated in FIG. 30, is preferably presented. If the reply is received within the specified period of time and the technician ID number was entered incorrectly, then preferably the Error: Login Failed screen, as shown in FIG. 22, is displayed. If the reply is received within the specified period of time and the technician ID number was entered correctly, then preferably one of five additional screens will be presented to the technician 304 depending on the selection that was previously made on the Technician Start screen, FIG. 19. If the button originally clicked on the Technician Start screen, FIG. 19, was Clock In, and it is currently within 15 minutes of the shift start time for the technician 304 through the end of the shift time, the Shift Start screen, as shown in FIG. 25 is preferably displayed after the Clock In time has been preferably saved to the database (embodying herein computer interface means for presenting confirmation of start of work shift to such at least one technician). Alternatively, if it is not within 15 minutes of the shift start time for the technician 304 through the end of the shift time, the Error: Start Shift, screen, as shown in FIG. 27, is preferably presented. If the button originally clicked on the Technician Start screen, FIG. 19, was Clock Out, then preferably one of two possible outcomes will occur: if the technician 304 previously clocked in, preferably Shift End, as shown in FIG. 28, is displayed after saving the Clock Out time to the database (embodying herein computer interface and storage means for receiving at least one end of work shift request from such at least one technician); or, if the technician 304 has not previously clocked in, preferably Error: End Shift, FIG. 26, is presented to the technician 304. If the button originally clicked on the Technician Start screen, FIG. 19, was View, then preferably the Schedule and Contact Information screen, FIG. 24, is presented to the technician 304. If the technician 304 selects the Cancel button, preferably all dialogs are closed and the Technician Start screen, FIG. 19, is displayed. Referring to FIG. 22, the Error: Login Failed screen, preferably a technician 304 must type in his or her personal technician ID number again and click the OK button to successfully login. The program then preferably sends this request to the server and waits for a reply for a specified period of time. During this time a progress bar preferably continually updates. If the program does not receive the reply within the specified period of time, then the Error: Request Not Received screen, as illustrated in FIG. 30, is preferably presented. If the reply is received within the specified period of time and the technician ID number is incorrect, then FIG. 22, the Error: Login Failed screen, is displayed again one last time. After the second incorrect technician ID number in this dialog, preferably the Notification screen, FIG. 23, is displayed, telling the technician 304 that the technician's ID number will be emailed. If the reply is received within the specified period of time and the technician ID number was entered correctly, then preferably one of five additional screens will be presented to the technician 304 depending on the selection that was previously made on the Technician Start screen, FIG. 19. If the button originally clicked on the Technician Start screen, FIG. 19, was Clock In, and it is currently within 15 minutes of the shift start time for the technician 304 through the end of the shift time, the start time for the technician 304 is recorded and the Shift Start screen, as shown in FIG. 25, is preferably displayed. Alternatively, if it is not within 15 minutes of the shift start time for the technician 304 through the end of the shift time, the Error: Start Shift, screen, as shown in FIG. 27, is preferably presented. If the button originally clicked on the Technician Start screen, FIG. 19, was Clock Out, then preferably one of two possible outcomes will occur: if the technician 304 previously clocked in, the actual shift end time of the technician 304 is recorded in the database (embodying herein computer interface means for presenting confirmation of end of work shift to such at least one technician) and preferably Shift End, as shown in FIG. 28, is displayed; or if the technician 304 has not previously clocked, preferably Error: End Shift, FIG. 26, is presented to the technician 304. If the button originally clicked on the Technician Start screen, FIG. 19, was View, then preferably the Schedule and Contact Information screen, FIG. 24, is presented to the technician 304. If the technician 304 selects the Cancel button, preferably all dialogs are closed and the Technician Start screen, FIG. 19, is displayed. Referring to FIG. 23, the Notification screen, upon presentation of this screen preferably the technician 304 may only select the OK button, which will preferably close all dialogs and return the supervisor 302 to the technician 304 Start screen, FIG. 19. Referring to FIG. 24, the Schedule & Contact Information screen, all technicians 304 have three choices. The technician 304 may preferably select the Print button in the Contact Information pane to print all of the contact information, the technician 304 may preferably select the Print button in the Schedule pane to print the work shift schedule, or the technician 304 may preferably select the Close button which will preferably close all dialogs and preferably display the Technician Start screen, FIG. 19 (embodying herein computer interface means for presenting planned shift scheduling to such at least one technician). Referring to FIG. 25, Shift Start screen, the technician 304 may preferably only select the OK button, which preferably closes all dialogs and displays the Technician Start screen, FIG. 19. Referring to FIG. 26, Error: End Shift screen, the technician 304 preferably may only select the OK button. This preferably closes all dialogs and FIG. 19, the Technician Start screen, is displayed. Referring to FIG. 27, Error: Start Shift screen, the technician 304 preferably may only select the OK button. This preferably closes all dialogs and FIG. 19, the Technician Start screen, is displayed. Referring to FIG. 28, Shift End screen, the technician 304 preferably may only select the OK button which closes all dialogs, and FIG. 19, the Technician Start screen, is displayed. Referring to FIG. 29, Error: Internet Connection screen, the technician 304 preferably may only select the OK button. This preferably closes all dialogs and FIG. 19, the Technician Start screen, is displayed. Referring to FIG. 30, Error: Request Not Received screen, the technician 304 preferably may only select the OK button. This preferably closes all dialogs and FIG. 19, the Technician Start screen is displayed. As described above, each of the activities of supervisor 302 are facilitated by particular on-location services management software capabilities. The following screens and interrelationships describe a preferred embodiment of the supervisor interface software 204. Referring to FIG. 31, Supervisor Start screen, preferably, the supervisor 302 has various choices when initiating access to the system. Selecting the text link preferably launches a browser window bringing the supervisor 302 to the website. Selecting the Clock In button, the Clock Out button, the View (Work Schedule/Contact Information) button, the View (Reports) button, or the Change (Create/Modify Employee Schedule) button preferably will pop up the Note screen, as shown in FIG. 32. Selecting the Close button will preferably close the entire application. Referring to FIG. 32, Note screen, the supervisor 302 must select the OK button to continue the login process. After this button is clicked, the dialog closes and the program checks to see if the personal computer belonging to the supervisor 302 is connected to the Internet. If the personal computer is connected to the Internet, then preferably the Login screen, as illustrated in FIG. 33 will pop up. If the personal computer belonging to the supervisor 302 is not connected to the Internet, then preferably the Error: Internet Connection screen, as shown in FIG. 40, will pop up. Referring to FIG. 33, the Supervisor Login screen, preferably a supervisor 302 must type in his or her personal supervisor ID number and click the OK button to successfully login. The program then preferably sends this request to the server and waits for a reply for a specified period of time. During this time a progress bar preferably continually updates. If the program does not receive the reply within the specified period of time then the Error: Request Not Received screen, as illustrated in FIG. 41, is preferably presented. If the reply is received within the specified period of time and the supervisor ID number was entered incorrectly, then preferably the Error: Login Failed screen, as shown in FIG. 34, is displayed. If the reply is received within the specified period of time and the supervisor ID number was entered correctly, then preferably one of seven additional screens will be presented to the supervisor 302, depending on the selection that was previously made on the Supervisor Start screen, FIG. 31. If the button originally clicked was Clock In, and it is currently within 15 minutes of the shift start time for the supervisor 302 through the end of the shift time, the Shift Start screen, as shown in FIG. 36, is preferably displayed. Alternatively, if it is not within 15 minutes of the shift start time for the supervisor 302 time through the end of the shift time, the Error: Start Shift, screen, as shown in FIG. 38, is preferably presented. If the button originally selected in FIG. 31, Supervisor Start screen, was Clock Out, then preferably one of two possible outcomes will occur: if the supervisor 302 previously clocked in, preferably Shift End, as shown in FIG. 39, is displayed; or if the supervisor 302 has not previously clocked in, preferably Error: End Shift, FIG. 37, is presented to the supervisor 302. If the button originally clicked in FIG. 31, Supervisor Start screen, was View (Work Schedule/Contact Information), then preferably FIG. 42, Schedule & Contact Information, is displayed to the supervisor 302. If the button originally clicked in FIG. 31, Supervisor Start screen, was View (Reports), then preferably Report, FIG. 43, is presented. If the button originally clicked in FIG. 31, Supervisor Start screen, was Change (Create/Modify Employee Schedule) then preferably FIG. 44, Schedule, is displayed. If the supervisor 302 selects the Cancel button on the Login screen, FIG. 33, preferably all dialogs are closed and the Supervisor Start screen, FIG. 31, is displayed. Referring to the Error: Login Failed screen, as illustrated by FIG. 34, preferably a supervisor 302 must type in his or her personal supervisor ID number again and click the OK button to successfully login. The program then preferably sends this request to the server and waits for a reply for a specified period of time. During this time a progress bar preferably continually updates. If the program does not receive the reply within the specified period of time then the Error: Request Not Received screen, as illustrated in FIG. 41, is preferably presented. If the reply is received within the specified period of time and the supervisor ID number is incorrect, then FIG. 34, the Error: Login Failed screen, is displayed again one last time. After the second incorrect supervisor ID number in this dialog, preferably the Notification screen, FIG. 35, is displayed, telling the supervisor 302 that the supervisor's ID number will be emailed. If the reply is received within the specified period of time and the supervisor ID number was entered correctly then preferably one of seven additional screens will be presented to the supervisor 302, preferably depending on the selection that was previously made on the Supervisor Start screen, FIG. 31. If the button originally clicked was Clock In, and it is currently within 15 minutes of the shift start time for the supervisor 302 through the end of the shift time, records the actual shift start time of the supervisor 302 is recorded in the database and the Shift Start screen, as shown in FIG. 36 is preferably displayed. Alternatively, if it is not within 15 minutes of the shift start time for the supervisor 302 through the end of the shift time, the Error: Start Shift, screen as shown in FIG. 38, is preferably presented. If the button originally selected in FIG. 31, Supervisor Start screen, was Clock Out, then preferably one of two possible outcomes will occur: if the supervisor 302 previously clocked in, the actual shift end time of the supervisor 302 is recorded in the database and preferably Shift End, as shown in FIG. 39, is displayed; or if the supervisor 302 has not previously clocked in, preferably Error: End Shift, FIG. 37, is presented to the supervisor 302. If the button originally clicked in FIG. 31, Supervisor Start screen, was View (Work Schedule/Contact Information), then preferably FIG. 42, Schedule & Contact Information, is displayed to the supervisor 302. If the button originally clicked in FIG. 31, Supervisor Start screen, was View (Reports), then preferably Report, FIG. 43, is presented. If the button originally clicked in FIG. 31, Supervisor Start screen, was Change (Create/Modify Employee Schedule) then preferably FIG. 44, Schedule, is displayed. If the supervisor 302 selects the Forgot Password button on the Error: Login Failed screen, FIG. 34, preferably all dialogs are closed and the Notification screen, FIG. 35, is displayed. Referring to FIG. 35, the Notification screen, upon presentation of this screen, preferably the supervisor 302 may only select the OK button which will preferably close all dialogs and return the supervisor 302 to the Supervisor Start screen, FIG. 31. Referring to FIG. 36, Shift Start screen, the supervisor 302 may only select the OK button. This preferably closes all other dialogs and returns the supervisor 302 to FIG. 31, the Supervisor Start screen. Referring to FIG. 37, Error: End Shift screen, the supervisor 302 preferably may only select the OK button. This preferably closes all dialogs and FIG. 31, the Supervisor Start screen, is displayed. Referring to FIG. 38, Error: Start Shift screen, the supervisor 302 preferably may only select the OK button. This preferably closes all dialogs and FIG. 31, the Supervisor Start screen, is displayed. Referring to FIG. 39, Shift End screen, the supervisor 302 preferably may only select the OK button. This preferably closes all dialogs and FIG. 31, the Supervisor Start screen, is displayed. Referring to FIG. 40, Error: Internet Connection screen, the supervisor 302 preferably may only select the OK button. This preferably closes all dialogs and FIG. 31, Supervisor Start screen, is displayed. Referring to FIG. 41 Error: Request Not Received screen, the supervisor 302 preferably may only select the OK button. This preferably closes all dialogs and FIG. 31, Supervisor Start screen, is displayed. Referring to FIG. 42, Schedule & Contact Information screen, all supervisors 302 preferably have three choices; and if he or she supervises more than one work cell, two additional options are preferably available. All supervisors 302 preferably have at least the following three choices. The supervisor 302 may select the Print button in the Contact Information pane to preferably print all of the contact information for technician 304. The supervisor 302 may select the Print button in the Schedule pane to preferably print the entire schedule for technician 304. The supervisor 302 may select the Close button to preferably close all dialogs and display FIG. 31, Supervisor Start screen. For supervisors 302 responsible for only one work cell, everything in the Work Cell pane preferably will be unavailable, the Work cell preferably will still be displayed in the menu, the Redisplay Contact Information/Schedule button preferably will still be displayed, and the Status bar preferably will be displayed without any solid bars. For supervisors 302 responsible for multiple work cells, selecting a Work Cell from the pull down menu list will preferably cause the specific cell to appear in the Work Cell pane; and preferably the Contact Information and Schedule are removed from the display. When a supervisor 302 selects the Redisplay Contact Information/Schedule button, the Contact Information and Schedule are removed from the display, all buttons and the entire display becomes grayed out and unavailable, and the program preferably sends this request to the server and continually waits for a reply for a specified period of time. During this time the progress bar preferably continually updates. If the program does not receive a reply within the specified period of time preferably, the Error: Request Not Received screen, FIG. 41, is displayed. If the program does receive the reply within the specified period of time, preferably all buttons and pull down menus cease to become grayed out and become available, and the Contact Information and Schedule preferably are refreshed for that selected Work Cell. Referring to FIG. 43, Feedback Report, all supervisors 302 preferably have five options. Selecting the Redisplay Report button preferably removes the Report from the display, and all buttons and the entire display preferably becomes grayed out and unavailable. The program preferably sends the report request to the server and preferably waits for a reply for a specified period of time. During this time the progress bar preferably continually updates. If the program does not receive the reply within the specified period of time, preferably the Error: Request Not Received screen, FIG. 41, is displayed. If the program does receive the reply within the specified period of time, preferably the Report is refreshed for that selected Work Cell, for the Start Date and End Date inclusive, and all buttons and pull down menus preferably become available. Selecting the Close button will preferably close all dialogs and display the Supervisor Start screen, FIG. 31. Selecting the Start Date from the pull down calendar preferably permits the selection of a desired date and the current Report is preferably removed from the display. Selecting the End Date from the pull down calendar preferably permits the selection of a desired date, and the current Report is preferably removed from the display. Supervisors responsible for only one work cell preferably will have no other options; and the work cell in the Choose Report Parameters pane preferably will be grayed out and unavailable, and the work cell will still be displayed in the menu. Supervisors responsible for multiple work cells preferably have the additional ability to select a particular work cell from the pull down menu list. Preferably, after a selection has been made, that one specific work cell appears and the current Report is removed from the display. The supervisor 302 then preferably has all the options described above available for completing a desired report. Referring to FIG. 44, Schedule, all supervisors 302 will have at least the following seven choices. Selecting a Shift from the Shift pull down menu list preferably permits Shift selection. Selecting a Date from the pull down calendar preferably permits Date selection. Selecting an Employee from the pull down menu list preferably permits Employee selection. Selecting the Add selection button in the Proposed Schedule pane preferably displays the Preview of Proposed schedule using the selected Shift, Date and Employee. Selecting the Remove selection button in the Proposed Schedule pane preferably displays requested removal in the Preview of Proposed schedule display using the selected Date, Shift and Employee. Selecting the Save to Server button preferably causes the buttons and the entire display to become grayed out and unavailable. The program then sends this request to the server and preferably waits for a reply for a specified period of time. During this time the progress bar preferably continually updates. If the program does not receive the reply within the specified period of time, then the Error: Request Not Received screen, FIG. 41, is preferably displayed. If the program does receive the reply within the specified period of time, preferably the entire display ceases to become grayed out and buttons become available and the schedule saved on the server is redisplayed in the Preview of Proposed Schedule pane. Selecting the Close button preferably closes all dialogs, and the Supervisor Start screen, FIG. 31, is displayed. Supervisors 302 responsible for only one work cell have all of the above options, but the Work Cell in the Change/Edit Schedule pane will be grayed out and unavailable. Preferably the cell will still be displayed in the menu. For supervisors 302 responsible for multiple work cells, all of the above options are preferably available plus one additional option. Selecting a Work Cell from the pull down menu list preferably presents the selected cell, the current Report is preferably removed from the display, and all buttons and pull down menus preferably become grayed out and unavailable. The program preferably then sends this request to the server and continually waits for a reply for a specified period of time. During this time the progress bar continually updates. If the program does not receive the reply within the specified period of time, preferably the Error: Request Not Received screen, FIG. 41, is displayed. If the program does receive the reply within the specified period of time, preferably all buttons and pull down menus become available, and preferably the schedule saved on the server is redisplayed in the Preview of Proposed Schedule pane. As described above, particular activities are facilitated by particular software available to customers 303, technicians 304 and supervisors 302 through a browser connection to the on-location services management software on the Web Server 101. The following screens and interrelationships describe a preferred embodiment of the website interface software 201. Referring to FIG. 45, the Home Page screen, a potential customer, supervisor 302, customer 303, or technician 304 may preferably make one of five choices. Preferably, selecting the “Interested in our service?” text link displays FIG. 46, the Interested in Our Service screen. Preferably, selecting the “Customer login” text link displays FIG. 48, the Customer login screen. Preferably, selecting the “Technician login” text link displays FIG. 52, the Technician login screen. Preferably, selecting the “Interested in becoming a technician?” text link displays FIG. 64, the Employment Interest screen. Preferably, selecting the “Supervisor login” text link preferably displays FIG. 65, the Supervisor Login screen. Referring to FIG. 46, the Interested In Our Service screen, a potential customer 303 preferably fills out all of his/her contact information and selects the submit button. After clicking the submit button, FIG. 47, the Thanks, You will be contacted screen is preferably displayed. Referring to FIG. 47, the Thanks, You will be contacted screen preferably displays a thank you message, and preferably the potential customer 303 is not prompted to take any further action. Referring to FIG. 48, the Customer login screen, the customer 303 preferably enters his or her phone number and customer ID number and selects the submit button. If the phone number or customer ID number was incorrect, then the Customer Login Incorrect screen, FIG. 49, is preferably displayed. If the phone number and customer ID number were correct, then the Customer Logged In screen, FIG. 50, is preferably displayed Referring to FIG. 49, the Customer Login Incorrect screen, the customer 303 enters his or her phone number and customer ID number and selects the submit button. If the phone number or customer ID was incorrect, then the Incorrect Login screen, FIG. 49, is preferably displayed again. If the phone number and customer ID are correct, then the Customer Logged In screen, FIG. 50, is preferably displayed. Referring to FIG. 50, the Customer Logged In screen, the customer 303 may preferably select one of five choices. Selecting the ‘Interested in adding service to another location’ radio button and clicking the submit button will preferably display the Thanks, You will be contacted screen, FIG. 47. Selecting the ‘Moving’ radio button and clicking the submit button will preferably display the Thanks, You will be contacted screen, FIG. 47. Selecting the ‘Moving service to another computer’ radio button and clicking-the submit button will preferably display the Thanks, You will be contacted screen, FIG. 47. Selecting the ‘Modify billing info’ radio button and clicking the submit button will preferably display the Modify billing information screen, FIG. 69. Selecting the ‘Comments’ radio button, completing his/her comments about the service, and clicking the submit button will preferably display the Thanks Response screen, FIG. 51. Referring to FIG. 51, the Thanks Response screen, a thank you for your response message is preferably displayed and the customer 303 is preferably not required to take any action. Referring to FIG. 52, the Technician Login screen, the technician 304 preferably enters his or her phone number and technician ID number and clicks the submit button. If either the phone number or technician ID number was incorrect, then the Technician Login Incorrect screen, FIG. 53, is preferably displayed. If the phone number and technician ID number are correct, then the Technician Logged In screen, FIG. 54, is preferably displayed. Referring to FIG. 53, the Technician Login Incorrect screen, the technician 304 preferably enters his or her phone number and technician ID number and selects the submit button. If either the phone number or technician ID number is incorrect, then the Technician Login Incorrect screen, FIG. 53, is preferably displayed again. If the phone number and technician ID number are correct, then the Technician Logged In screen, FIG. 54, is preferably displayed. Referring to FIG. 54, the Technician Logged In screen, the technician 304 preferably may select one of two choices. Selecting the ‘Complete work order’ radio button and clicking the submit button will preferably display the Complete work order screen, FIG. 55. Selecting the ‘Initial customer setup’ radio button will preferably display the Purchase Service screen, FIG. 61. Referring to FIG. 55, the Complete Work Order screen, preferably the technician 304 fills in the Work Order Number, the Time in, the Time out, preferably selects either the “Yes” or “No” radio button to indicate the customer 303 needs a contractor to solve the problem the customer 303 has, and clicks the Submit button. If the Work Order Number entered has not been previously recorded by the system, it is incorrect and preferably the Incorrect Work Order screen, FIG. 56, is displayed. If the Work Order Number is correct and the “Yes” radio button for “Does the customer 303 need services from a contractor?” question was selected, then the Find Contractor screen, FIG. 57, is preferably displayed (embodying herein computer interface and storage means for receiving indication of any need relating to repair service from such selected at least one technician). If the Work Order Number is correct and the “No” radio button for “Does the customer need services from a contractor?” question was selected, the information is saved to the database (embodying herein computer interface and storage means for recording on-location electronics troubleshooting service information), then the Customer Satisfaction screen, FIG. 58, is preferably displayed (embodying herein computer interface and storage means for receiving start time of such on-location electronics troubleshooting service from such selected at least one technician; and embodying herein computer interface and storage means for receiving end time of such on-location electronics troubleshooting services from such selected at least one technician). Referring to FIG. 56, the Incorrect Work Order screen, preferably the technician 304 fills in the Work Order Number, the Time in, the Time out, preferably selects either the “Yes” or “No” radio button to indicate the customer 303 needs a contractor to solve the problem the customer 303 has and clicks the Submit button. If the Work Order Number entered has not been previously recorded by the system, then it is incorrect and preferably the Incorrect Work Order screen, FIG. 56, is displayed again. If the Work Order Number is correct and the “Yes” radio button for “Does the customer need services from a contractor?” question was selected, then the Find Contractor screen, FIG. 57, is preferably displayed. If the Work Order Number is correct and the “No” radio button for “Does the customer need services from a contractor?” question was selected, then the Customer Satisfaction screen, FIG. 58, is preferably displayed Referring to FIG. 57, the Find Contractor screen, preferably the technician 304 selects either the Commercial button or Residential button and then selects a contractor specialty from the drop down list and clicks the Submit button which preferably saves all the information in the database and displays the Customer Satisfaction screen, FIG. 58 (embodying herein computer interface and storage means for recording on-location electronics troubleshooting service information; and embodying herein computer interface and storage means for receiving indication of selected type of such repair service from such selected at least one technician). Referring to FIG. 58, the Customer Satisfaction screen, preferably the customer 303 fills in his/her customer ID number and indicates his or her level of satisfaction by selecting either the “Completely Satisfied” radio button, the “Satisfied” radio button or the “Unsatisfied” radio button and clicks the Submit button (embodying herein computer interface and storage means for receiving customer satisfaction evaluation). If the customer ID number entered was correct, then the Thanks screen, FIG. 60, is preferably displayed. If the customer ID number entered was incorrect, then FIG. 59, the Customer Satisfaction Incorrect Customer Id screen is preferably displayed. Referring to FIG. 59, the Customer Satisfaction Incorrect Customer Id screen, preferably the customer 303 fills in his/her customer ID number and indicates his or her level of satisfaction by selecting either the “Completely Satisfied” radio button, the “Satisfied” radio button or the “Unsatisfied” radio button and clicks the Submit button. If the customer ID number entered was correct, then the Thanks screen, FIG. 60, is preferably displayed. If the customer ID number entered was incorrect, then FIG. 59, the Customer Satisfaction Incorrect Customer Id screen is preferably displayed again. Referring to FIG. 60, the Thanks Service screen, preferably presents a thank you message and preferably the customer 303 is not required to take any action. Referring to FIG. 61, the Purchase Service screen, preferably the customer 303 fills in Name, Address, City, State, Zip, Phone, Email, Credit Card Number, and Expiration and clicks the submit button. Preferably, if the customer's 303 credit card information was accepted, then the information is saved and then the Download screen, FIG. 62 is preferably displayed (embodying herein computer interface and storage means for registering customer data relating to at least one customer; (embodying herein database means for maintaining a database of such customer data relating to such at least one customer). Preferably, if the credit card belonging to the customer 303 was not accepted, then the Re-Enter Credit Card Information screen, FIG. 63, is preferably displayed. Referring to FIG. 62, the Download screen, preferably the technician 304 selects the Download Software text link to begin the customer interface software 202 download to the personal computer belonging to the customer 303 and preferably activates the downloaded customer interface software 202. Referring to FIG. 63, the Re-Enter Credit Card Information screen, preferably the customer 303 fills in Name, Address, City, State, Zip, Phone, Email, Credit Card Number, and Expiration and clicks the submit button. Preferably, if the customer's 303 credit card information was accepted, then the Download screen, FIG. 62 is preferably displayed. Preferably, if the credit card belonging to the customer 303 was not accepted, then the Re-Enter Credit Card Information screen, FIG. 63, is preferably displayed again. Referring to FIG. 64, the Employment Interest screen, preferably the potential employee fills in Name, Address, City, State, Zip, Phone, Email and skills and clicks the Submit button; then the Thanks you will be contacted screen, FIG. 47, is preferably displayed. Referring to FIG. 65, the Supervisor Login screen, preferably the supervisor 302 enters his or her phone number and supervisor ID number and clicks the Submit button. If either the phone number or supervisor ID number is incorrect, then the Supervisor Login Incorrect screen, FIG. 66, is preferably displayed. If the phone number and supervisor ID number are correct, then the Create Employee Account screen, FIG. 67, is preferably displayed. Referring to FIG. 66, the Supervisor Login Incorrect screen, preferably the supervisor 302 enters his or her phone number and supervisor ID number and clicks the Submit button. If the either phone number or supervisor ID number is incorrect, then the Supervisor Login Incorrect screen, FIG. 66, is preferably displayed again. If the phone number and supervisor ID number are correct, then the Create Employee Account screen, FIG. 67, is preferably displayed. Referring to FIG. 67, the Create Employee Account screen, preferably the new employee fills in Name, Address, City, State, Zip, Cell Phone, Home Phone, Pager, Email and clicks the Submit button, the information is saved and the Download Employee Software screen, FIG. 68, is preferably displayed (embodying herein computer interface and storage means for registering technician data relating to at least one technician having electronics-technician abilities relating to providing such on-location electronics troubleshooting services; and (embodying herein database means for maintaining a database of the technician data relating to such at least one technician). Referring to FIG. 68, the Download Employee Software screen, preferably the supervisor 302 selects the Download Software text link on the employee's personal computer to download the technician interface software 207 and preferably activates the technician interface software 207. Referring to FIG. 69, the Modify Billing Information screen, preferably the customer 303 fills in Name, Address, City, State, Zip, Primary Phone Number, Secondary Phone Number, Email address, Credit Card Number, Expiration, and clicks the submit button, which preferably displays the Billing Information Changed screen, FIG. 70. Referring to FIG. 70, the Billing Information Changed screen, preferably a thank you message and confirmation of updated information is displayed. Preferably, the customer 303 is not prompted to do anything. Referring now to FIG. 71, there is presented a schematic overview of the business functions which may be preferably conducted using a standard telephone or cellular telephone as an alternative preferred embodiment of the present invention. First, a customer 303 may preferably use a telephone, as illustrated by the services request step 521, to place a call which is preferably answered by telephone interface 209 particularly programmed to collect the customer ID (account) number and pin number from the customer 303 and to subsequently store the information for later transfer to the on-location services management software on the Web Server 101. All the necessary validations and edits are performed by the telephone interface 209 to ensure validity of the information entered by the customer 303. Second, after receiving an on-location electronics troubleshooting service request the telephone interface 209 creates and sends an on-location electronics troubleshooting service request email containing the customer id and pin number to the on-location services management software on the Web Server 101. Preferably, when an on-location electronics troubleshooting service request is received and recorded in the database, the on-location services management software will automatically initiate a dispatch message to a technician 304 using the methods described above in the technician dispatch step 422 in FIG. 4. Preferably, when the telephone interface 209 receives technician 304 start or end shift times, a technician 304 start time email or technician 304 end time email is sent to the on-location services management software on the Web Server 101 and recorded automatically as if the technician 304 had entered the information as described in the technician schedule step 532 shown in FIG. 5. Preferably, the telephone interface 209 receives supervisor 302 start or end shift times, a supervisor 302 start time email or supervisor 302 end time email is sent to the on-location services management software on the Web Server 101 and recorded automatically as if the supervisor 302 had entered the information as described in the supervisor schedule step 542 shown in FIG. 5. Third, as shown in on-location services step 604, preferably after completion of the on-location electronics troubleshooting services the technician 304 will initiate a telephone call to the telephone interface 209 to record the completion of the service call, record whether there is a need for repair services, and record the satisfaction level of the customer 303. All the necessary validations and edits are performed by the telephone interface 209 to ensure validity of the information entered by the technician 304. Fourth, as shown in the telephone technician shift start and end step 605, the technician 304 calls into the telephone interface 209, enters his or her technician ID number and indicates whether this is the start of the shift or the end of the shift. The telephone interface 209 then sends a technician 304 start shift email or a technician 304 end shift email to the on-location services management software on the Web Server 101. All the necessary validations and edits are performed by the telephone interface 209 to ensure validity of the information entered by the technician 304. Fifth, as shown in the telephone supervisor shift start and end step 606, the supervisor 302 calls into the telephone interface 209, enters his or her supervisor ID number, and indicates whether this is the start of the shift or the end of the shift. The telephone interface 209 then sends a supervisor 302 start shift email or a supervisor 302 end shift email to the on-location services management software on the Web Server 101. All the necessary validations and edits are performed by the telephone interface 209 to ensure validity of the information entered by the supervisor 302. Although the illustrated overview is one preferred embodiment, one skilled in the art will appreciate that, under appropriate circumstances, various sections may be omitted, rearranged or adapted in various ways for various purposes. Referring now to FIG. 72, an additional preferred embodiment of the present invention is illustrated in which a customer 303 may purchase a desired piece of low-voltage electronic equipment from electronics equipment suppliers 307 that have been selected for their product line and delivery standards. In the electronics equipment supplier agreement step 711, preferably the owner/manager 301 will identify particular electronics equipment suppliers 307 who provide appropriate types and brands of low-voltage electronics, who are willing to provide very rapid delivery to customers 303, and who will preferably pay a commission based on the value of the products sold to customers 303. In the electronics equipment supplier maintenance step 712, the owner/manager 301 will preferably add a hyperlink to the electronics equipment supplier web server 203 once an agreement is completed with an electronics equipment supplier 307. The hyperlink will allow customers 303 to access the electronics equipment supplier web site 203 selected by the customers 303. In the electronics equipment purchase step 701, a customer 303 will select the desired item and arrange payment through the electronics equipment supplier web site 203. In turn, the electronics equipment supplier 307 will schedule delivery of the purchased equipment directly with the customer 303, as shown in the electronics equipment delivery step 704. Periodically, each electronics equipment suppliers 307 will remit to the owner/manager 301 commissions for electronics equipment purchased by customer 303 coming to the electronics equipment supplier web site 203 from the on-location services management software operating on the Web Server 101, as depicted in the payment step 713. If desired, a customer 303 may request on-location services to assist with the implementation of the purchased electronics equipment using the same steps as depicted in FIG. 4, of services request step 421, the technician dispatch step 422 and problem resolution 423. Referring now to FIG. 73, a schematic overview of an alternate preferred embodiment of the primary business functions of the present invention is shown. In a preferred embodiment of the present invention, in the initial contact step 311, a customer 303 learns of the on-location electronics troubleshooting services from advertising and other marketing activities and preferably expresses an interest in the services through the Web Site Home Page, FIG. 45, Interested in Our Service screen, FIG. 46, and the Thanks, You will be contacted screen, FIG. 47. Preferably, in customer contact step 321, the Licensee 801 contacts the customer 303 using one or more typical methods; and preferably the customer 303 agrees to subscribe to the on-location electronics troubleshooting services for a period of at least one year and preferably agrees to pay the agreed monthly fee via an automatic monthly charge to a credit card belonging to the customer 303. According to an alternate preferred embodiment of the present invention, customer 303 pays an initial setup fee and a “per incident” fee each time the customer requests service. Upon reading the teachings of this specification, those with ordinary skill in the art will now understand that, under appropriate circumstances, considering issues such as business and marketing strategy, types of clients, type of service being provided by licensee, etc., other payment arrangements may suffice, such as, for example, eliminating the initial setup fee, prepaying for services, paying an annual fee, etc. Preferably, Licensee 801 pays licensing fees to Licensor 802, as indicated by step 803, in exchange for a license to use the software and/or business methods of licensor 802, as indicated by step 804. Preferably, licensee 801 pays an initial licensing fee, followed by periodic licensing fees (preferably paid monthly) as indicated by step 803. Preferably, at least a portion of the licensing fees are based on the number of technicians 304 employed by licensee 801. Upon reading the teachings of this specification, those with ordinary skill in the art will now understand that, under appropriate circumstances, considering issues such as business and marketing strategy, types of clients, type of service being provided by licensor, etc., other licensing arrangements may suffice, such as, for example, a fixed one-time licensing fee, annual licensing fees, licensing fees based on the number of customers 303, licensing fees based on geographic region or some other pertinent factor, etc. In a preferred embodiment of the present invention, once a potential customer 303 has agreed to subscribe to the on-location electronics troubleshooting services as indicated by step 311, a technician 304 will be dispatched to the home or place of business of the potential customer 303 as indicated by step 323. Preferably, once the technician 304 is at the service location of the customer 303, he or she will complete the customer sign up step 322 by logging to the on-location'services management software operating on the Web Server 101, as shown in FIG. 45, FIG. 52, FIG. 53 and FIG. 54; and the customer 303 will preferably enter his or her name and address and contact information and credit card information, as illustrated in FIG. 61 and FIG. 62 (embodying herein computer interface and storage means for registering customer data relating at least one customer). After entry and acceptance of the credit card information, as indicated by step 351, step 352 and step 353, the customer information is stored in the database (embodying herein database means for maintaining a database of such customer data for such at least one customer; and (embodying herein computer interface and storage means for receiving credit card account information from such at least one customer), and the customer interface software 202 is downloaded from the Web Server 101 and installed on a personal computer which is, or can be, connected to the Internet 107, as shown in FIG. 3. Preferably, the technician 304 instructs the customer 303 on the usage of the customer interface software 202 (see FIG. 2). Preferably, when customer 303 needs assistance, customer 303 submits a request for service (preferably via website 101 as indicated by step 311 or via telephone call to licensee as indicated by step 321). Preferably, technicians 304 are then notified, as indicated by step 322, to assist the customer 303, as indicated by step 323. Preferably, technicians 304 provide service trouble-shooting, assisting, and maintaining low voltage equipment, such as, for example, computer networking audio/visual equipment, communications systems, security systems, Internet connectivity, etc. Upon reading the teachings of this specification, those with ordinary skill in the art will now understand that, under appropriate circumstances, considering issues such as business and marketing strategy, types of clients, type of service being provided by licensor, etc., having technicians provide other services may suffice, such as, for example, repairing other types of equipment, janitorial services, etc. Further, upon reading the teachings of this specification, those with ordinary skill in the art will now understand that, under appropriate circumstances, considering issues such as business and marketing strategy, types of clients, type of service being provided by licensor, etc., using customer interface software for uses other than dispatching technicians may suffice, such as, for example, to make requests to customer service representatives, place orders at restaurants, and other situations in which a request for service can benefit from automated selection and dispatch of available resources to provide the requested service, etc. Referring again to FIG. 73, in the arrange for credit card processing step 351, the licensee 801 will preferably conclude an agreement with appropriate credit card processing companies 305 to permit verification of customer 303 credit cards, the processing of credit card payment requests and automatic deposit of the payments to a specified bank account on behalf of the licensee 801. In the request payment step 352, each month the on-location services management software will preferably automatically create a payment request for each customer 303 and transmit it to the credit card processing company 305 for payment to the licensee 801. Alternatively, customer 303 may alternatively chooses to pay on a per visit basis using a credit card at the time of completion of the on-location services. Preferably, the technician 304 will enter the necessary credit card information in the 322 step which is preferably followed by the request payment step 352. In the receive payments step 353, the licensee 801 preferably receives the payments from customer 303 (embodying herein computer processor means for managing collecting at least one fee from such at least one customer relating to such on-location electronics troubleshooting services; and embodying herein computer processor and communications means for requesting such at least one payment from such at least one credit card account on behalf of such at least one customer substantially automatically at pre-determined intervals; and computer processor and communications means for requesting such at least one payment from such at least one credit card account on behalf of such at least one customer at completion of on-location electronics troubleshooting services by such at least one technician; and embodying herein computer processor means for recording such payment on behalf of such at least one customer). Referring now to FIG. 74, which presents an overview of how the invention may, under appropriate circumstances, suffice to provide a variety of benefits and be implemented to solve many different problems in different service and management environments. According to an alternate preferred embodiment of the present invention, the “customers” may be hotel guests, building tenants, services customers, or internal employees of a company as represented by service requester 807. Preferably, licensee 801 manages website 101 as indicated by step 806. Preferably, service requester 807 makes service requests via website 101 or telephone as indicated by step 311. Preferably, website software contacts service provider 808 as indicated by step 322 by telephone and/or by an Internet interface. Preferably, service provider 808 assists service requester 807 as indicated by step 323. Preferably, licensee 801 pays license fees to licensor 802, as indicated by step 803, in exchange for the license, as indicated by 804. Preferably, license fees are determined in various ways including level of usage as measured by the number of service requests managed, the number of service providers managed, the number of employees or some similar method. With respect to providing hotel services to hotel guests, preferably the invention may be implemented to accept requests for toiletries, food, etc. via a user-interface on a personal computer in each room and/or have the guest call an internal or a 1-800 number to register their request. Preferably the request gets processed through the software and the appropriate service provider receives the message through a phone/pager and addresses the guest's needs without additional human intervention. Thus services to the guests are improved, workloads reduced and analysis of the types of requests and levels of service is provided through improved reporting. With respect to services provided through call centers, such as AT&T for example. Preferably, customers would utilize the software installed on their computers or call a 1-800 number to initiate a question or request. Preferably, in turn the invention would identify the appropriate customer service representative in the call center, based on the nature of the request, who would then call the customer back. The customer receives improved service, get the problem solved and the company may potentially reduce staffing levels and better track and manage requests from start to closure. With respect to Information Technology (IT) departments, preferably the invention may be used to accept, dispatch and manage technical requests for support and service from internal employees. Preferably an internal employee requiring assistance would utilize the software installed on their computers or call a 1-800 number to initiate a request. Preferably, in turn the invention would identify the appropriate IT support representative, based on the nature of the request, who would then provide the service to the requesting internal employee. The internal employees would get their problem solved more quickly and the company may potentially reduce staffing levels and better track and manage requests from start to closure. With respect to building managers for large buildings, preferably the invention may be used to accept, dispatch and manage all manner of requests for support and services from building tenants. Preferably tenants requiring assistance would utilize the software installed on their computers or call a 1-800 number to initiate a request. Preferably, in turn the invention would identify the employee or trades contractor, based on the nature of the request, who would then provide the service to the requesting tenant. Tenants would get their problems solved more quickly and the building manager may potentially reduce staffing levels minimize trades contractor charges and better track and manage requests from start to closure. With respect to employee scheduling and timekeeping, preferably the invention may be utilized to permit employees working away from the office, or in the office, to schedule their time and clocked in and out. Preferably, employees may be required to logon when a shift starts and log out when it ends using the invention. Preferably, this can be accomplished through software user interface on a personal computer or by calling a 1-800 number. Preferably, this use of the invention can eliminate a very manual and tedious process and problems with lying about hours worked, having employees clock in before a shift starts, clocking out before a shift ends, not properly adding up hours worked in a week by a given employee, not having a supervisor know when his/her employees are on/off the clock, etc. Although the illustrated overviews provide at least one preferred embodiment, those skilled in the art will appreciate that, under appropriate circumstances, various sections may be omitted, rearranged or adapted in various ways for various purposes. Upon reading this specification, those skilled in the art will see that, considering similarities, differences and advantages, under appropriate circumstances as a non-preferred embodiment, the methods described herein may be applied to a variety of on-location services other than low-voltage electronics troubleshooting. Although applicant has described applicant's preferred embodiments of this invention, it will be understood that the broadest scope of this invention includes such modifications as diverse shapes and sizes and materials. Such scope is limited only by the below claims as read in connection with the above specification. Further, many other advantages of applicant's invention will be apparent to those skilled in the art from the above descriptions and the below claims. | <SOH> BACKGROUND <EOH>This invention relates to a system for providing on-location electronics troubleshooting services to consumers and businesses in a manner that improves timeliness and quality of responses to requests for assistance. This system is made possible by the widespread availability of the Internet and improvements in related software. In the past few years, the pace of change in low voltage electronics has accelerated and is likely to continue into the future. Low voltage electronics, typified by personal computers, also includes video and stereo equipment and all manner of devices from telephones to personal digital assistants. Not only has the number of devices increased, but their complexity has increased to the point where many are no longer installable without significant assistance from retailers and manufacturers. The increase in the number and complexity of low-voltage devices has made it increasingly difficult to troubleshoot problems when they inevitably arise. Recent economic troubles have forced many low-voltage manufacturers and dealers to reduce live telephone-based customer support as well in favor or email exchanges, FAQ (Frequently Asked Questions) lists or user forums. Even when support is available, it is often of marginal quality due to the low skill level of telephone support representatives and it has inherent limitations of time of day and the ability of the two parties to communicate clearly about a problem. Email exchanges and user forums are often time-consuming and require more knowledge than the user has and usually require multiple days to receive an answer, which answer has a high likelihood of being incorrect. FAQ lists can be helpful, but are usually limited to addressing only the most basic issues. Today, beyond telephone support, the sources of assistance for consumers and small businesses are typically limited to: on-location assistance provided on an on-call basis; or technically oriented friends or family. And using either of these alternatives often means delays in getting a problem resolved in a timely manner. On-location full time technical support staff, which would theoretically be more responsive, is never an option for consumers; and most small businesses are unable to afford the cost. Additionally, telephone-based support is less and less often provided at no charge. All the current alternatives are generally only available during business hours on business days; therefore, no help is available on nights and weekends. Consumers and small businesses are often forced to “live with a problem” for much longer than they would like or to pay a premium for on-location help on a one-time basis. Additionally, most problems encountered are not intrinsic failures of a device, but are grounded in misunderstandings, user ignorance, and errors by users during installation or set up. This means that most consumers' and small businesses' low-voltage technical problems can be resolved quickly by a technically competent person working at the consumer's or business's location. Furthermore, the problems faced by low-voltage devices manufacturers are common to a wide variety of other industries and service providers. Examples of other areas which face similar problems are services providers such as telephone companies, hotels, and information technology departments in large organizations and other service providers such as telephone and cable companies. Coincident with these changes in low-voltage devices, a wide range of interactive devices have been developed to provide information to a variety of users via communications networks. These interactive devices include, for example, computers connected to various computer on-line services, interactive kiosks, interactive television systems, and a variety of other wired and wireless devices, such as personal data assistants (PDA's) and the like. In particular, the popularity of computer on-line services has grown immensely in popularity over the last decade. Computer on-line services are provided by a wide variety of different companies. In general, most computer on-line services are accessed via the Internet. The Internet is a global network of computers. One popular part of the Internet is the World Wide Web, or the “Web.” The World Wide Web contains computers that display graphical and textual information. Computers that provide information on the World Wide Web are typically called “Websites.” A Website is defined by an Internet address that has an associated electronic page, often called a “homepage.” Generally, a homepage is an electronic document that organizes the presentation of text, graphical images, audio and video into a desired display. These Websites are operated by a wide variety of entities, which are typically called “providers”. A user may access the Internet via a dedicated high-speed line or by using a personal computer (PC) equipped with a conventional modem or a variety of other wired and wireless devices. Special interface software, called “browser” software, is installed within the PC or other access device. When the user wishes to access the Internet by normal telephone line, an attached modem is automatically instructed to dial the telephone number associated with the local Internet host server. The user can then access information at any address accessible over the Internet. Two well-known web browsers, for example, are the Netscape Navigator browser marketed by Netscape Communications Corporation and the Internet Explorer browser marketed by Microsoft Corporation. Information exchanged over the Internet is typically encoded in HyperText Mark-up Language (HTML) format. The HTML format is a scripting language that is used to generate the homepages for different content providers. In this setting, a content provider is an individual or company that places information (content) on the Internet so that others can access it. As is well known in the art, the HTML format is a set of conventions for marking different portions of a document so that each portion appears in a distinctive format. For example, the HTML format identifies or “tags” portions of a document to identify different categories of text (e.g., the title, header, body text, etc.). When a web browser (or suitable executable program) accesses an HTML document, the web browser (or suitable executable program) reads the embedded tags in the document so it appears formatted in the specified manner. An HTML document can also include hyperlinks, which allow a user to move from one document to another document on the Internet. A hyperlink is an underlined or otherwise emphasized portion of text that, when selected using an input device such as a mouse, activates a software connection module that allows the user to jump between documents or pages (i.e., within the same Website or to other Websites). Hyperlinks are well known in the art, and have been sometimes referred to as anchors. The act of selecting the hyperlink is often referred to as “clicking on” the hyperlink. The advent and subsequent increased use of the Internet and its interconnected communications systems, coupled with new wireless technologies, may provide an opportunity for the development of new and advanced methods of providing skilled, timely on-location electronics troubleshooting services at a reasonable cost to the customer. Additionally, a variety of other industries which provide some form of on-site service and support are also faced with problems and requirements are similar to those faced by the low-voltage electronics industry. For example, hotels often have difficulty managing requests for deliveries to guest's rooms. Frequently guests request delivery of toiletries, food, etc., be to their room. Today, the requester (person or people) must call the front desk. Typically, person the front desk must in turn request that someone else deliver the requested items. This process presents a number of problems including no consistent way to track requests and deliveries of those items, difficulty in monitoring performance and completion, the involvement of several people and no tracking of the frequency of requests by the type of request, deliveries, repairs, etc. Another example, many companies use call centers (not always in the US) to provide customer support. At best these can be frustrating and time consuming experiences for customers because it is frequently difficult to find the right person to help resolve the problem. This leads to unhappy customers and the need to maintain large call centers with their attendant expense. A further example, information technology departments for many companies manage and process thousands of requests for help and service. Frequently, this support effort suffers from communications methods that ensure the highest priority problems are addressed first. Additionally, while voice mail and other forms of communication permit leaving a message with a person they do not permit centralized management including prioritization and assignment of the requests. Thus, problems are not resolved on timely basis and the support staff must each deal with conflicting priorities and frequent changes in work. A final example, high rise building managers must deal with a constant flow of incoming service requests by tenants to the building manager. The building manager must then request the services of a trade contractor to address the problem. Finally the building manager must then follow up to ensure the problem is resolved. All this is typically very disjointed requiring many phone calls and time and effort for many people which results in improper work, late completions and unhappy tenants and trades contractors. This opportunity is also applicable to a variety of other industries which provide some form of on-site service and support because their problems and requirements are similar to those faced by the low-voltage electronics industry. Such new and advanced methods (such as the inventions provided herein by applicant) of providing on-location support solve many of the current problems outlined above. | <SOH> SUMMARY OF THE INVENTION <EOH>In accordance with a preferred embodiment hereof, this invention provides an Internet-website-client-server-assisted system, relating to providing on-location electronics troubleshooting services, comprising the steps of: registering customer information relating to at least one customer; registering technician information relating to at least one technician having electronics-technician abilities relating to providing such on-location electronics troubleshooting services; maintaining a database, on at least one Internet website client server, of such customer information relating to such at least one customer; maintaining a database, on such at least one Internet website client server, of such technician information relating to such at least one technician; collecting automatically, using such at least one Internet website client server, at least one fee from such at least one customer relating to such on-location electronics troubleshooting services; receiving, on such at least one Internet website client server, requests relating to such on-location electronics troubleshooting services from such at least one customer; notifying automatically, using such at least one Internet website client server, such at least one technician to provide such on-location electronics troubleshooting services requested by such at least one customer; receiving on-location electronics troubleshooting service information, on at least one Internet website client server, from such at least one technician; and maintaining a database, on such at least one Internet website client server, of such on-location electronics troubleshooting service information. Moreover, it provides such an Internet-website-client-server-assisted system wherein such at least one customer and such at least one technician are sufficiently co-located within geographical areas to provide appropriate response times. Additionally, it provides such an Internet-website-client-server-assisted system, wherein such step of receiving on-location electronics troubleshooting service information by such at least one technician comprises the steps of: receiving start time of such on-location electronics troubleshooting service, on such at least one Internet website client server, from selected such at least one technician; receiving end time of such on-location electronics troubleshooting services, on such at least one Internet website client server, from selected such at least one technician; storing such start time of such on-location electronics troubleshooting service on such at least one Internet website client server; and storing such end time of such on-location electronics troubleshooting service on such at least one Internet website client server. Also, it provides such an Internet-website-client-server-assisted system further comprising the steps of: receiving indication of any need relating to repair service, on such at least one Internet website client server, from such selected at least one technician; receiving indication of selected type of such repair service, on such at least one Internet website client server, from such selected at least one technician; storing such indication of any need relating to repair service on such at least one Internet website client server; storing such selected type of such repair service, on such at least one Internet website client server; selecting such at least one repair service of such selected type of repair service; and notifying such selected at least one repair service to contact such at least one customer. In addition, it provides such an Internet-website-client-server-assisted system further comprising the steps of: receiving customer satisfaction evaluation from such selected at least one technician; and storing such customer satisfaction evaluation. And, it provides such an Internet-website-client-server-assisted system, wherein such step of collecting automatically, using such at least one Internet website client server, at least one fee from such at least one customer relating to such on-location electronics troubleshooting services comprises the steps of: agreeing to at least one payment of a specified amount by such at least one customer; and receiving such at least one payment. Further, it provides such an Internet-website-client-server-assisted system, wherein such step of receiving such at least one payment comprises the steps of; providing of credit card account information by such at least one customer; storing such at least one credit card account information, on at least one Internet website client server, relating to such at least one customer; authorizing at least one charge to such credit card account of such at least one customer; storing such authorization of at least one charge to such credit card account, on at least one Internet website client server, of such at least one customer; requesting at least one payment from such at least one credit card account on behalf of such at least one customer; and recording such at least one payment, on at least one Internet website client server, on behalf of such at least one customer. Even further, it provides such an Internet-website-client-server-assisted system, wherein such step of requesting at least one payment from such at least one credit card account on behalf of such at least one customer comprises the step of requesting such at least one payment from such at least one credit card account on behalf of such at least one customer substantially automatically at pre-determined intervals. Moreover, it provides such an Internet-website-client-server-assisted system, wherein such step of requesting at least one payment from such at least one credit card account on behalf of such at least one customer comprises the step of requesting such at least one payment from such at least one credit card account on behalf of such at least one customer at completion of on-location electronics troubleshooting services by such at least one technician. Additionally, it provides such an Internet-website-client-server-assisted system further comprising the steps of: notifying such at least one customer requesting such on-location electronics troubleshooting services of estimated time of arrival of notified such at least one technician; and providing such on-location electronics troubleshooting services to such at least one customer. Also, it provides such an Internet-website-client-server-assisted system wherein such step of notifying such at least one customer requesting such on-location electronics troubleshooting services of estimated time of arrival of notified such at least one technician comprises the steps of: providing to such at least one customer such estimated time of arrival by such notified such at least one technician; and recording such estimated time of arrival provided by such notified such at least one technician. In addition, it provides such an Internet-website-client-server-assisted system further comprising the steps of: providing such on-location electronics troubleshooting services to such at least one customer at any time of day; and providing such on-location electronics troubleshooting services to such at least one customer on any day. And, it provides such an Internet-website-client-server-assisted system, wherein such step of registering customer information relating to at least one customer further comprises the steps of: recruiting such at least one customer; obtaining agreement from such at least one customer to pay for such on-location electronics troubleshooting services; recording such customer information, on at least one Internet website client server, relating to such at least one customer; wherein such customer information comprises service location address; at least one contact name; at least one contact telephone number; and assigning such service location address to at least one geographic dispatch area. Further, it provides such an Internet-website-client-server-assisted system, wherein such customer information further comprises: customer name; customer billing address; customer email address; customer credit card number; and customer credit card number expiration date. Even further, it provides such an Internet-website-client-server-assisted system further comprising the steps of: providing on-location assistance relating to implementation of such on-site customer interface module of such Internet-website-client-server-assisted system to such at least one customer; and providing on-location usage training relating to such on-site customer interface module of such Internet-website-client-server-assisted system to such at least one customer. Moreover, it provides such an Internet-website-client-server-assisted system, wherein such step of registering technician information relating to at least one technician having electronics-technician abilities relating to providing such on-location electronics troubleshooting services comprises the steps of: establishing a plurality of qualification criteria relating to selecting such at least one technician; wherein such qualification criteria comprise geographic location of residence of such at least one technician, and required minimum competency levels relating to electronics-technician abilities; and recruiting such at least one technician; and recording technician information, on at least one Internet website client server, relating to selected such at least one technician; wherein such technician information comprises technician name, technician home address, technician home telephone number, technician email address, and technician electronics-technician skills; selecting such at least one technicians using such plurality of qualification criteria; assigning such selected at least one technician a unique identification number; assigning such technician home address to at least one geographic dispatch area; and implementing at least one technician user interface module of such Internet-website-client-server-assisted system. Additionally, it provides such an Internet-website-client-server-assisted system, wherein such technician information further comprises: technician cellular phone number; and technician pager number. Also, it provides such an Internet-website-client-server-assisted system wherein such step of receiving, on such at least one Internet website client server, requests relating to such on-location electronics troubleshooting services from such at least one customer comprises the steps of: inputting of login identification information, on such at least one Internet website client server, from such at least one customer; validating login identification information from such at least one customer; receiving confirmation of accuracy, on such at least one Internet website client server, of such customer information; receiving contact information, on such at least one Internet website client server, relating to such current at least one on-location electronics troubleshooting request; submitting of at least one problem description relating to such current at least one on-location electronics troubleshooting request by such at least one customer; and receiving of such at least one problem description relating to such current at least one on-location electronics troubleshooting request, on such at least one Internet website client server, from such at least one customer. In addition, it provides such an Internet-website-client-server-assisted system, wherein such step of notifying automatically, using such at least one Internet website client server, such at least one technician to provide such on-location electronics troubleshooting services requested by such at least one customer comprises the steps of: selecting such at least one technician using dispatch selection criteria; wherein such dispatch selection criteria comprises identifying at least one of such at least one technician assigned to such same geographic dispatch area as such service location of such at least one customer requesting on-location electronics troubleshooting services, and identifying at least one such technician having greatest elapsed time since such last notification; and notifying such at least one technician to provide such on-location electronics troubleshooting services requested by such at least one customer; and recording time of such notification, on such at least one Internet website client server, of such at least one technician. And, it provides such an Internet-website-client-server-assisted system further comprising the steps of: receiving at least one work shift start request, on such at least one Internet website client server, from such at least one technician; storing time of day and date of receipt of such work shift start request, on such at least one Internet website client server, from such at least one technician; sending confirmation of start of work shift to such at least one technician; receiving at least one end of work shift request, on such at least one Internet website client server, from such at least one technician; storing time of day and date of receipt of such at least one end of work shift request, on such at least one Internet website client server, from such at least one technician; and sending confirmation of end of work shift to such at least one technician. Further, it provides such an Internet-website-client-server-assisted system further comprising the step of presenting planned shift scheduling to such at least one technician. Even further, it provides such an Internet-website-client-server-assisted system further comprising the steps of: preparing text-based reports; and preparing graphical reports. In accordance with another preferred embodiment hereof, this invention provides an Internet website client-server computer system relating to providing on-location electronics troubleshooting services comprising, in combination: computer interface and storage means for registering customer data relating to at least one customer; computer interface and storage means for registering technician data relating to at least one technician having electronics-technician abilities relating to providing such on-location electronics troubleshooting services; database means for maintaining a database of such customer data relating to such at least one customer; database means for maintaining a database of such technician data relating to such at least one technician; computer processor means for managing collecting at least one fee from such at least one customer relating to such on-location electronics troubleshooting services; computer interface and storage means for receiving requests relating to such on-location electronics troubleshooting services from such at least one customer; computer processor and communications-device means for automatically notifying such at least one technician to provide such on-location electronics troubleshooting services requested by such at least one customer; and computer interface and storage means for recording on-location electronics troubleshooting service information. Moreover, it provides such an Internet website client-server computer system further comprising: computer processor means for substantially fully automating such dispatching of such at least one technician to such at least one customer relating to such on-location troubleshooting. Also, it provides such an Internet website client-server computer system further comprising: computer processing means for selecting such at least one technician using dispatch selection criteria; wherein such dispatch selection criteria comprises such at least one technician assigned to such same geographic dispatch area of such at least one customer requesting on-location electronics troubleshooting services, and such at least one technician having greatest elapsed time since last such dispatch; and communications device means for notifying such at least one technician to provide such on-location electronics troubleshooting services requested by such at least one customer; and computer processor means for recording time of such notification of such at least one technician. Additionally, it provides such an Internet website client-server computer system, wherein such computer processor means for managing collecting at least one fee from such at least one customer relating to such on-location electronics troubleshooting services further comprises: computer interface and storage means for receiving credit card account information from such at least one customer; computer processor and communications means for requesting payment from such at least one credit card account on behalf of such at least one customer; and computer processor means for recording such payment on behalf of such at least one customer. Also, it provides such an Internet-website-client-server-assisted system, wherein such computer processor and communications means for requesting payment from such at least one credit card account on behalf of such at least one customer comprises computer processor and communications means for requesting such at least one payment from such at least one credit card account on behalf of such at least one customer substantially automatically at pre-determined intervals. In addition, it provides such an Internet-website-client-server-assisted system, wherein such computer processor and communications means for requesting payment from such at least one credit card account on behalf of such at least one customer comprises computer processor and communications means for requesting such at least one payment from such at least one credit card account on behalf of such at least one customer at completion of on-location electronics troubleshooting services by such at least one technician. And, it provides such an Internet website client-server computer system, wherein such computer interface and storage means for receiving requests relating to such on-location electronics troubleshooting services from such at least one customer further comprises: computer interface means for inputting login identification information by such at least one customer; computer processing means for validating login identification information from such at least one customer; computer interface means for receiving confirmation of accuracy of such customer information; computer interface and storage means for receiving contact information relating to such current at least one on-location electronics troubleshooting request; and computer interface and storage means for receiving at least one problem description relating to such current at least one on-location electronics troubleshooting request by such at least one customer. Further, it provides such an Internet website client-server computer system, further comprising: computer interface and storage means for receiving at least one work shift start request from such at least one technician; computer interface means for presenting confirmation of start of work shift to such at least one technician; computer interface and storage means for receiving at least one end of work shift request from such at least one technician; computer interface means for presenting confirmation of end of work shift to such at least one technician; computer interface means for presenting planned shift scheduling to such at least one technician; computer interface and processor means for presenting text reports; and computer interface and processor means for presenting graphical reports. Even further, it provides such an Internet website client-server computer system, wherein such computer interface and storage means for recording on-location electronics troubleshooting service information further comprises: computer interface and storage means for receiving start time of such on-location electronics troubleshooting service from such selected at least one technician; computer interface and storage means for receiving end time of such on-location electronics troubleshooting services from such selected at least one technician; computer interface and storage means for receiving indication of any need relating to repair service from such selected at least one technician; computer interface and storage means for receiving indication of selected type of such repair service from such selected at least one technician; computer processor means for selecting such at least one repair service of such selected type of repair service; communications device means for notifying such selected at least one repair service to contact such at least one customer; and computer interface and storage means for receiving customer satisfaction evaluation. In accordance with another preferred embodiment hereof, this invention provides at least one network-client-server-assisted system, relating to assisting providing services to at least one customer, comprising the steps of: maintaining a database on such at least one network-client-server-assisted system of customer-assistance information relating to such at least one customer; receiving, on such at least one network-client-server-assisted system, requests relating to such services from such at least one customer; and notifying automatically, using such at least one network-client-server-assisted system, at least one service provider to provide such services requested by such at least one customer. | 20040113 | 20130423 | 20050120 | 62002.0 | 1 | WILSON, CANDICE D C | ON-LOCATION ELECTRONICS TROUBLESHOOTING SERVICES SYSTEM | SMALL | 0 | ACCEPTED | 2,004 |
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10,757,316 | ACCEPTED | Capacitive touch on/off control for an automatic residential faucet | A capacitive touch-controlled automatic faucet comprises: a spout, a magnetically latching valve, a proximity sensor, a handle, a capacitive touch-control, and a logical control. The proximity sensor is sensitive to motion of objects within a detection zone of the proximity sensor. The handle determines a water flow rate and temperature. The capacitive touch-control is positioned in the spout and generates an output signal while the touch-control is in contact with a user. The logical control receives the output signal, and toggles the magnetically latching valve when the output signal begins and ends within a period of time less than a predetermined threshold, but does not toggle the magnetically latching valve when the output signal persists for a period longer than the predetermined threshold. The faucet has a manual mode, wherein the proximity sensor is inactive, and a hands-free mode, wherein water flow is toggled in response to the proximity sensor. | 1. A faucet comprising: a spout; a passageway that conducts water flow through the spout; a electrically operable valve disposed within the passageway; a manual valve disposed within the passageway in series with the electrically operable valve; a manual handle that controls the manual valve; and a capacitive touch control that is positioned in the spout, where the capacitive touch control toggles the electrically operable valve. 2. The faucet of claim 1, further comprising a logical control that toggles the electrically operable valve when the touch control is touched and released within a period of time shorter than a predetermined threshold, but does not toggle the electrically operable valve when the touch control is touched for a period longer than the predetermined threshold. 3. The faucet of claim 2, wherein the logical control toggles the electrically operable valve when the touch control is touched and released within a period of time between a predetermined lower bound and a predetermined upper threshold. 4. The faucet of claim 3, wherein the predetermined lower bound is about 50 ms, and the predetermined upper threshold is about 250 ms. 5. The faucet of claim 1, wherein the electrically operable valve is a magnetically latching valve. 6. The faucet of claim 1, further comprising a proximity sensor that is sensitive to motion of objects within a detection zone of the proximity sensor. 7. The faucet of claim 6, wherein the faucet has: a manual mode, wherein the proximity sensor is inactive; and a hands-free mode, wherein water flow is toggled on and off in response to the proximity sensor. 8. The faucet of claim 1, further comprising a second capacitive touch control disposed within the manual handle that toggles the electrically operable valve. 9. A faucet comprising: a spout; a passageway that conducts water flow through the spout; an electrically operable valve disposed within the passageway and having an opened position, in which water is free to flow through the passageway, and a closed position, in which the passageway is blocked; a manual valve disposed within the passageway in series with the electrically operable valve; a manual handle that controls the manual valve; a first capacitive touch-control that is positioned in the spout and that generates a first output signal while the first capacitive touch-control is in contact with a user; a second capacitive touch-control that is positioned in the manual handle and that generates a second output signal while the second capacitive touch-control is in contact with the user; a logical control that receives the first and second output signals, and which toggles the electrically operable valve between the opened position and the closed position when either the first output signal or the second output signal begins and ends within a period of time between a predetermined lower bound and a predetermined upper bound; and a proximity sensor that is sensitive to motion of objects within a detection zone of the proximity sensor; wherein the faucet has a manual mode, wherein the proximity sensor is inactive, and a hands-free mode, wherein the magnetically latching valve is toggled between the opened position and closed position in response to the proximity sensor, subject to being overridden by the output signal and logical control. 10. A faucet comprising: a spout; a passageway that conducts water flow through the spout; an electrically operable valve disposed within the passageway; a sensor operably connected to the electrically operable valve via a logical control, the logical control generating a control signal when the sensor senses an activation event having a duration less than a predetermined threshold; and wherein the electrically operable valve actuates in response to the control signal. 11. The faucet of claim 10, wherein the sensor is a touch sensor, and the activation event is contact with the touch sensor. 12. The faucet of claim 10, wherein the electrically operable valve is a magnetically latching valve. 13. The faucet of claim 10, further comprising a proximity sensor that produces a proximity sensor output signal corresponding to motion of one or more objects within a detection zone of the proximity sensor. 14. The faucet of claim 13, wherein the faucet has: a manual mode, wherein the proximity sensor is inactive; and a hands-free mode, wherein water flow is toggled on and off in response to the proximity sensor output signal. 15. The faucet of claim 10, further comprising a second electrically operable valve having a plurality of partially closed positions, the second electrically operable valve being disposed in the passageway upstream of a mixing point, such that the second electrically operable valve affects the flow rate of only one of a hot or cold water supply. 16. The faucet of claim 15, wherein the logical control directs the second electrically operable valve to change among open, closed, and the plurality of partially closed positions in response to a duration of contact with the touch control. 17. A fluid flow control for a faucet having an electrically operable valve that is actuated in response to a control signal, the fluid flow control comprising: a sensor that detects activation events; a logical control in communication with the sensor, the logical control generating a control signal when the sensor observes an activation event occurring less than a predetermined number of times within a predetermined period, but which does not generate the control signal when the sensor observes an activation event occurring more than the predetermined number of times within a predetermined period. 18. A fluid flow control for a faucet having an electrically operable valve that is actuated in response to a control signal, the fluid control comprising: a sensor that observes activation events; and a logical control operably connected to the sensor, the logical control generating a control signal when the sensor observes an activation event having a duration less than a predetermined threshold, but which does not generate the control signal when the sensor observes an activation event having a duration longer than the predetermined threshold. 19. The fluid flow control of claim 18, wherein the sensor is a proximity sensor that is sensitive to motion of objects within a detection zone of the proximity sensor. 20. The fluid flow control of claim 19, wherein the predetermined lower bound is about 50 ms and the predetermined upper threshold is about 250 ms. 21. The fluid flow control of claim 18, wherein the sensor is a capacitive touch sensor. | BACKGROUND 1. Field of the Invention The present invention generally relates generally to the field of automatic faucets. More particularly, the present invention relates to a capacitive touch on/off controller for automatic residential faucets. 2. Description of the Related Art Automatic faucets have become popular for a variety of reasons. They save water, because water can be run only when needed. For example, with a conventional sink faucet, when a user washes their hands the user tends to turn on the water and let it run continuously, rather than turning the water on to wet their hands, turning it off to lather, then turning it back on to rinse. In public bathrooms the ability to shut off the water when the user has departed can both save water and help prevent-vandalism. One early version of an automatic faucet was simply a spring-controlled faucet, which returned to the “off” position either immediately, or shortly after, the handle was released. The former were unsatisfactory because a user could only wash one hand at a time, while the latter proved to be mechanically unreliable. One solution was the hands-free faucet. These faucets employed a proximity detector and an electric power source to activate water flow without the need for a handle. In addition to helping to conserve water and prevent vandalism, hands-free faucets had additional advantages, some of which began to make them popular in homes, as well as public bathrooms. For example, there is no need to touch the faucet to activate it; with a conventional faucet, a user with dirty hands may need to wash the faucet after washing their hands. In public facilities non-contact operation is more sanitary. Hands-free faucets also provide superior accessibility for the disabled, the elderly, and those who need assisted care. Although hands-free faucets have many advantages, some people prefer to directly control the start and stop of water, depending on how they use the faucet. For example, if the user wishes to fill the basin with water to wash something, the hands-free faucet could be frustrating, since it would require the user to keep a hand continuously in the detection zone of the sensors. Thus, for many applications touch control is preferable to hands-free control. Touch control provides a useful supplement to manual control. Typically, faucets use the same manual handle (or handles) to turn the water flow off and on and to adjust the rate of flow and water temperature. Touch control therefore provides both a way to turn the water off an on with just a tap, as well as a way to do so without having to readjust the rate of flow and water temperature each time. Consequently, some touch-control faucets have been developed, especially for kitchen sink applications. In some cases, the touch control may be as simple as a push-button. In certain faucets, the touch control is implemented using a strain gauge that responds to the impulse from a tap. Strain gauges, however, have a number of shortcomings. Because they are sensitive to force, rather than actual contact, their response over the period of a given contact is uneven. For example, when a user first makes contact with a touch sensor based on a strain gauge, the initial impulse of contact appears as a substantially magnified force. After the initial contact, the response of the strain gauge is related to other confounding variables, such as the pressure of the contact, and the direction of the applied force. Since the purpose of a touch-control is to provide the simplest possible way for a user to activate and deactivate the flow of water, the location of the touch control is an important aspect of its utility. The easier and more accessible the touch control, the more effort is saved with each use, making it more likely that the user will take advantage of it, thereby reducing unnecessary water use. Since the spout of the faucet is closest to the position of the user's hands during most times while the sink is in use, it is an ideal location for the touch control. However, in practice it has proved unsuitable, because the spout of a typical kitchen sink is swiveled between the two basins found in most kitchen sinks. With a touch-control positioned in the spout, when the user touches the spout to swing it from one basin to the other (or to otherwise reposition the spout), the faucet is undesirably deactivated (or activated). The handle of a faucet is another good location for a touch sensor, because the user naturally makes contact with the handle of the faucet during operation. Another issue with automatic faucets of all varieties is battery life. For both safety and cost reasons many people prefer to use battery power to operate hands-free faucets. Consequently, power consumption is an important design consideration. Thus, what is needed is touch-control water faucet that can distinguish between contact for the purpose of activating or deactivating water flow and contact for the purpose of swinging the spout from one basin to the other, and which can be operated on standard commercial batteries without having to change the batteries more than once during a typical three-month period. The present invention is directed towards meeting these needs, among others. SUMMARY OF THE INVENTION In a first embodiment, the present invention provides a faucet comprising a spout and a passageway that conducts water flow through the spout. An electrically operable valve is disposed within the passageway; a manual valve is disposed within the passageway in series with the electrically operable valve; and a manual handle controls the manual valve. A capacitive touch control is positioned in the spout, and the capacitive touch control toggles the electrically operable valve. In a second embodiment, the present invention provides a faucet comprising a spout and a passageway that conducts water flow through the spout. A magnetically latching valve is disposed within the passageway and has an opened position, in which water is free to flow through the passageway, and a closed position, in which the passageway is blocked. A manual valve is disposed within the passageway in series with the electrically operable valve. A manual handle controls the manual valve. A first capacitive touch control is positioned in the spout and generates a first output signal while the touch control is in contact with a user. A second capacitive touch control is positioned in the manual handle and generates a second output signal while the touch control is in contact with a user. A logical control receives the first and second output signals, and toggles the magnetically latching valve when an output signal begins and ends within a period of time between a predetermined lower bound and a predetermined upper threshold. A proximity sensor is sensitive to motion of objects within a detection zone of the proximity sensor. The faucet has a manual mode, wherein the proximity sensor is inactive, and a hands-free mode, wherein the magnetically latching valve is toggled between its opened and closed positions in response to the proximity sensor, subject to being over-ridden by the output signal and logical control. In a third embodiment, the present invention provides a faucet comprising a spout, a touch control disposed within the spout, and a passageway conducting water flow through the spout. An electrically operable valve is disposed within the passageway. A logical control toggles the electrically operable valve when the touch control is touched and released within a period of time less than a predetermined threshold, but does not toggle the electrically operable valve when the touch control is touched for a period longer than the predetermined threshold. In a fourth embodiment, the present invention provides a capacitive touch control for a faucet having an electrically operable valve that is toggled in response to a toggle signal, the touch control comprising an electrode and a logical control that generates the toggle signal when the touch control is touched and released within a period of time less than a predetermined threshold, but which does not generate a toggle signal when the touch control is touched for a period longer than the predetermined threshold. BRIEF DESCRIPTION OF THE DRAWINGS Although the characteristic features of this invention will be particularly pointed out in the claims, the invention itself, and the manner in which it may be made and used, may be better understood by referring to the following descriptions taken in connection with the accompanying figures forming a part hereof. FIG. 1 is a diagram of a logical control for a capactive touch-sensor according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the preferred embodiment and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Such alternations to and further modifications of the invention, and such further applications of the principles of the invention as described herein as would normally occur to one skilled in the art to which the invention pertains, are contemplated, and desired to be protected. A preferred embodiment faucet according to the present invention includes a touch sensor in the spout of the faucet, and another in the manual handle. The touch sensor in the spout permits a user to turn water flow on and off merely by tapping the spout. In the preferred embodiment, the faucet distinguishes between a tap on the spout to turn the water flow on or off, and grasping the spout, for example to swing it from one basin of the sink to the other. Thus, the faucet provides an easy and convenient way to turn the water off and on without having to adjust the water flow rate and temperature. The touch sensor in the handle can also be used for a tap control, which distinguishes between grasping the handle to adjust the water flow rate or temperature, and merely tapping it to toggle water flow off or on. Preferably, though, the touch sensor in the handle is used to activate water flow automatically when the faucet is in a hands-free mode, as discussed in greater detail in the concurrently filed application entitled “Multi-Mode Hands-Free Automatic Faucet.” Regardless, the touch sensor in the handle provides an additional source of input data for the faucet, which permits the faucet to more accurately determine the intent of the user, thereby providing greater water savings while being intuitive and easy to use. A preferred embodiment touch-control faucet according to the present invention employs a capacitive touch detector, as is known in the art. In the preferred embodiment, a QT118H, manufactured and sold by Quantum Research Group (www.qprox.com) is used. The QT118H is an electronic device that receives a signal from any suitable electrode and interprets it to determine when it has been touched by a user by observing the changes in the electrode's capacitance. The QT118H is advantageously used in the present invention because it can distinguish between changes that are caused by contact with a user and changes caused by, especially, drops of water that might contact the electrode. Despite the advantageous features of the QT118H, use of the spout for the touch detector's electrode requires some measures to sufficiently isolate the spout from ground. For the touch detector in the spout, this is relatively easily accomplished, since the spout can be surrounded by a non-conductive covering upon which the touch detector's electrode can “float.” However, with the manual handle the electrical isolation is more difficult to achieve. The handle and mechanical valve must be isolated from the rest of the sink, using rubber, plastic, or other such non-conductive components, as would occur to a person of ordinary skill in the art. However, because the handle is connected directly to the manual valve, which, in turn, contacts the water running through the faucet, this is not sufficient, by itself. (Use of a completely non-conductive manual valve is possible, but undesirable because of cost and mechanical reliability.) It has been determined by the inventors that, in order to operate the QT118H with a sufficiently low power drain to make battery power a viable option, the resistance between the electrode and ground must be at least about 10 kω. Assuming essentially perfect isolation through the solid components of the faucet, this can be accomplished by separating the mechanical valve from the metallic water pipes through a long column of water. The required length of that column is a function of the conductivity of the water, which, it will be appreciated, varies enormously from geographic location to location. It has been determined by the inventors that even with water that is 6σ above the mean conductivity in the various water supplies throughout the United States, the required 10 kΩ of resistance is achieved when the water column is at least 18 inches long, with a circular cross-sectional diameter {fraction (1/4)} inch in diameter. Thus, the preferred embodiment faucet according to the present invention includes at least 18 inches of non-conductive piping with a ¼ inch internal diameter that extends below the mechanical valve under the sink. The water pipe is connected to the faucet only at the end of that pipe. (It will be appreciated that two such pipes are required-one for the hot water supply and one for the cold.) Preferably, these extensions are included in the form of flexible, non-conductive hoses. In addition to isolating the manual valve from ground, it has also been determined by the inventors that performance of the capacitive touch sensors can be improved by tying the circuit ground to earth ground. Furthermore, for the sake of consistency the distal ends of the hoses should always be well grounded. This is inherently accomplished when the water pipes are copper (or another metal). However, when the pipes are plastic (or PVC), the ends of the hoses should be deliberately grounded. Quantum Research Group also provides a variety of other suitable ICs that convert electrodes into touch sensors, including the rest of the QT110 series. It will be appreciated that these IC have varying performance, including variations in the extent to which the electrode must be isolated from ground and the amount of power they draw. Thus, while the preferred embodiment employs the QT118H with an electrode separated from ground by 10 kΩ, other suitable configurations are possible, and will be apparent to those skilled in the art. Indeed, other capacitive touch detectors can be used as well. Suitable capacitive touch-detection systems are disclosed, for example, in U.S. Pat. No. 6,518,820 to Gremm, and in U.S. Pat. No. 5,790,107 to Kasser, et al., which are hereby incorporated herein in their entireties. Electrode design is also discussed in detail in, for example, “Capacitive Sensors, Design and Applications,” by Larry Baxter (IEEE Press). While the preferred embodiment employs capacitive touch detection, in certain alternative embodiments other kinds of touch detecting are employed. Capacitive touch detection is preferable to, for example, the use of a strain gauge, because it provides a means to observe the length of contact, which can be used to infer whether the touch control was deliberately tapped with the intention of toggling water flow, or whether it was incidentally touched while the spout was repositioned. It will, however, be appreciated that other means of detecting physical contact can also be used, so long as they provide a means to detect both when the contact is initiated and when it is terminated. In the preferred embodiment the touch sensor is used with a logical control to actuate an automatic valve that is placed in series with the manual valve, so that the water flow can be toggled on and off without the need to reposition the manual valve. In this way, the water can be toggled on and off without altering the flow rate and the water temperature. The logical control is preferably implemented with electrical or electronic circuitry, as is known in the art, that controls an electrically controlled valve, such as a magnetically latching solenoid valve. The physical mechanism by which the water flow is toggled is not critical, but, a magnetically latching pilot-operated solenoid valve is advantageously used, in part to limit power consumption. Regardless, this valve is preferably relatively slow-opening and -closing, in order to reduce pressure spikes, known as “water hammer,” and undesirable splashing. On the other hand, the valve should not open or close so slowly as to be irritating to the user. It has been determined that a valve opening or closing period of at least 0.5 second sufficiently suppresses water hammer and splashing. In the preferred embodiment the touch control in the spout and the touch control in the handle articulate the electrically operable valve via separate logical controls. (Although the logical controls are preferably distinct, they are preferably implemented with a single electric or electronic circuit.) In the preferred embodiment the touch control in the spout is controlled by a logical control that distinguishes between a grasping contract, such as occurs when a user touches the spout to reposition it, and a mere tap, which is presumed to be an instruction to toggle water flow. FIG. 1 is a flowchart illustrating the logical control for the spout touch sensor in a preferred embodiment touch-control faucet according to the present invention, indicated generally at 100. The logical control initializes at start 101. At 103 it is determined whether the touch detector has detected contact. If no contact is detected, the process loops back to point 102, and step 103 is repeated until contact is detected. When, at step 103, contact is detected, at step 104 the length of time that the contact lasts is measured. It will be appreciated that this can be performed, for example, by another loop which waits for the contact to no longer be detected. Alternatively, it could be performed externally by the touch detector itself, and the length of contact can be input to the logical control 100 as an additional input. At step 105 it is determined whether the contact time is below a predetermined threshold. Preferably, the predetermined threshold is approximately 0.25 second. When the spout is touched in order to reposition it, typically the contact lasts longer than about 0.25 second. On the other hand, when a user taps the spout to instruct the faucet to toggle water flow, the contact generally lasts less than about 0.25 second. Consequently, this threshold value causes the logical control 100 to distinguish between these two causes of contact with a user. In addition to an upper bound on contact time, a lower bound may also be used. Such a lower bound can screen out erroneous stray signals from the capacitive sensor, such as might be caused by splashing water, for example. It has been determined by the inventors that using a lower bound on the order of about 0.05 second (50 milliseconds) eliminates most or all undesired cut-outs of the water flow. Thus, in the preferred embodiment, at step 105 it is determined whether the contact time is between about 50 and about 250 milliseconds. If at step 105 it is determined that the contact time is not below the predetermined upper threshold (or is below the predetermined lower bound), the logical control returns to point 102, where the contact-detection loop is begun again. If it is determined at step 105 that the contact time is below the predetermined upper threshold (and is also above any predetermined upper bound), at step 106 the water valve is opened to initiate flow, at step 107 an auto-shutoff timer is started, and the logical control proceeds to point 108. At step 109 it is determined whether the touch detector has detected contact. If so, at step 110 the length of contact is determined, as was done at step 104. Then, at step 111 it is determined whether the length of contact is greater than a predetermined threshold (not necessarily the same threshold as was used in step 105). If the length of contact is greater than the predetermined threshold, the logical control returns to point 108, whereupon the contact-detection loop begins again. If the length of the contact is less than the predetermined threshold, at step 112 the water valve is closed, and the logical control returns to point 102. If, at step 109, contact with the touch-detector is not detected, then at step 114 it is determined whether the auto-shutoff timer has expired. If the auto-shutoff timer has not expired, then the logical control returns to point 108. If the auto-shutoff timer has expired, the logical control proceeds to step 112, where the valve is closed, and then returns to point 102. In the preferred embodiment the faucet operates in at least two modes: a manual mode, wherein the electrically operable valve remains open, and a hands-free mode, wherein the electrically operable valve is toggled in response to signals from a proximity sensor. This is described in greater detail in the concurrently filed application entitled “Multi-Mode Hands-Free Automatic Faucet,” which is hereby incorporated herein in its entirety. Thus, in the manual mode the faucet is controlled by the position of the handle like a conventional faucet, while in the hands-free mode, the flow is toggled on and off in response to the proximity sensor (while the flow temperature and rate are still controlled by the handle position, as normally). It will be appreciated that the logical control 100 can be used to permit touch-control of the faucet by tapping the spout in either of these two modes. In certain embodiments, the logical control 100 is also used to interpret the signal from the touch sensor in the handle. However, preferably, while the faucet is in hands-free mode a separate logical control is used. Preferably, all other logical control of the faucet is overridden between the start of a touch detection by the touch sensor in the handle, and the opening of the electrically controlled valve, without respect to the duration of the touch. In this way, grasping the handle will always cause the water to flow. This makes it convenient for the user to adjust the water flow. In certain alternative embodiments the logical control is adapted to respond to the duration of contact with the touch control to control the rate of flow, in addition to toggling the water flow on and off. In these embodiments the electrically operable valve is preferably not a magnetically latching valve. Instead, preferably, a valve is used that can be electrically controlled to be placed in range of positions, including an open position, a closed position, and a plurality of partially closed positions. It will be appreciated that the duration of contact with the touch control can be associated with any of a variety of instructions to the electrically operable valve. For example, in certain embodiments, contact below a given duration (e.g., 50 ms) is ignored, contact within a relatively short window (e.g., 50-250 ms) is interpreted as an instruction to toggle water flow completely on or off, and contact for a greater duration is interpreted as a command to gradually decrease (or increase) flow rate as long as the contact is maintained. It will be appreciated that this principle can be extended to touch control of the temperature of the water flow. In order to adjust the temperature, it will be appreciated that an electrically controlled valve must be included at a point in the water flow passageway upstream of the mixing point (typically at the mechanical valve). Preferably an additional electrically controlled valve is used, so that water flow can be toggled on and off with a single electrically operable valve (downstream of the mixing point). In certain alternative embodiments, a single additional electrically operable valve is included in the hot water line above the mixing point, and extended contact with the touch sensor is interpreted as a command to gradually alter the temperature of the water flow by gradually closing the hot water supply's electrically controlled valve. Using these principles, those skilled in the art will appreciate that a system can be developed to provide virtually any desired flow rate and temperature behavior. It will be appreciated that the present invention can be used in conjunction with a hands-free control arrangement that interprets motion of objects, rather than merely their proximity, by employing a position-sensitive device (“PSD”) as the proximity detector. A PSD is sensitive to motion of an object within its detection zone because it can sense the distance of an object from the sensor. This is discussed in greater detail in the concurrently filed application entitled “Control Arrangement for an Automatic Residential Faucet,” which is hereby incorporated herein in its entirety. While the invention has been illustrated and described in detail in the drawings and foregoing description, the description is to be considered as illustrative and not restrictive in character. Only the preferred embodiments, and such alternative embodiments deemed helpful in further illuminating the preferred embodiment, have been shown and described. It will be appreciated that changes and modifications to the forgoing can be made without departing from the scope of the following claims. | <SOH> BACKGROUND <EOH>1. Field of the Invention The present invention generally relates generally to the field of automatic faucets. More particularly, the present invention relates to a capacitive touch on/off controller for automatic residential faucets. 2. Description of the Related Art Automatic faucets have become popular for a variety of reasons. They save water, because water can be run only when needed. For example, with a conventional sink faucet, when a user washes their hands the user tends to turn on the water and let it run continuously, rather than turning the water on to wet their hands, turning it off to lather, then turning it back on to rinse. In public bathrooms the ability to shut off the water when the user has departed can both save water and help prevent-vandalism. One early version of an automatic faucet was simply a spring-controlled faucet, which returned to the “off” position either immediately, or shortly after, the handle was released. The former were unsatisfactory because a user could only wash one hand at a time, while the latter proved to be mechanically unreliable. One solution was the hands-free faucet. These faucets employed a proximity detector and an electric power source to activate water flow without the need for a handle. In addition to helping to conserve water and prevent vandalism, hands-free faucets had additional advantages, some of which began to make them popular in homes, as well as public bathrooms. For example, there is no need to touch the faucet to activate it; with a conventional faucet, a user with dirty hands may need to wash the faucet after washing their hands. In public facilities non-contact operation is more sanitary. Hands-free faucets also provide superior accessibility for the disabled, the elderly, and those who need assisted care. Although hands-free faucets have many advantages, some people prefer to directly control the start and stop of water, depending on how they use the faucet. For example, if the user wishes to fill the basin with water to wash something, the hands-free faucet could be frustrating, since it would require the user to keep a hand continuously in the detection zone of the sensors. Thus, for many applications touch control is preferable to hands-free control. Touch control provides a useful supplement to manual control. Typically, faucets use the same manual handle (or handles) to turn the water flow off and on and to adjust the rate of flow and water temperature. Touch control therefore provides both a way to turn the water off an on with just a tap, as well as a way to do so without having to readjust the rate of flow and water temperature each time. Consequently, some touch-control faucets have been developed, especially for kitchen sink applications. In some cases, the touch control may be as simple as a push-button. In certain faucets, the touch control is implemented using a strain gauge that responds to the impulse from a tap. Strain gauges, however, have a number of shortcomings. Because they are sensitive to force, rather than actual contact, their response over the period of a given contact is uneven. For example, when a user first makes contact with a touch sensor based on a strain gauge, the initial impulse of contact appears as a substantially magnified force. After the initial contact, the response of the strain gauge is related to other confounding variables, such as the pressure of the contact, and the direction of the applied force. Since the purpose of a touch-control is to provide the simplest possible way for a user to activate and deactivate the flow of water, the location of the touch control is an important aspect of its utility. The easier and more accessible the touch control, the more effort is saved with each use, making it more likely that the user will take advantage of it, thereby reducing unnecessary water use. Since the spout of the faucet is closest to the position of the user's hands during most times while the sink is in use, it is an ideal location for the touch control. However, in practice it has proved unsuitable, because the spout of a typical kitchen sink is swiveled between the two basins found in most kitchen sinks. With a touch-control positioned in the spout, when the user touches the spout to swing it from one basin to the other (or to otherwise reposition the spout), the faucet is undesirably deactivated (or activated). The handle of a faucet is another good location for a touch sensor, because the user naturally makes contact with the handle of the faucet during operation. Another issue with automatic faucets of all varieties is battery life. For both safety and cost reasons many people prefer to use battery power to operate hands-free faucets. Consequently, power consumption is an important design consideration. Thus, what is needed is touch-control water faucet that can distinguish between contact for the purpose of activating or deactivating water flow and contact for the purpose of swinging the spout from one basin to the other, and which can be operated on standard commercial batteries without having to change the batteries more than once during a typical three-month period. The present invention is directed towards meeting these needs, among others. | <SOH> SUMMARY OF THE INVENTION <EOH>In a first embodiment, the present invention provides a faucet comprising a spout and a passageway that conducts water flow through the spout. An electrically operable valve is disposed within the passageway; a manual valve is disposed within the passageway in series with the electrically operable valve; and a manual handle controls the manual valve. A capacitive touch control is positioned in the spout, and the capacitive touch control toggles the electrically operable valve. In a second embodiment, the present invention provides a faucet comprising a spout and a passageway that conducts water flow through the spout. A magnetically latching valve is disposed within the passageway and has an opened position, in which water is free to flow through the passageway, and a closed position, in which the passageway is blocked. A manual valve is disposed within the passageway in series with the electrically operable valve. A manual handle controls the manual valve. A first capacitive touch control is positioned in the spout and generates a first output signal while the touch control is in contact with a user. A second capacitive touch control is positioned in the manual handle and generates a second output signal while the touch control is in contact with a user. A logical control receives the first and second output signals, and toggles the magnetically latching valve when an output signal begins and ends within a period of time between a predetermined lower bound and a predetermined upper threshold. A proximity sensor is sensitive to motion of objects within a detection zone of the proximity sensor. The faucet has a manual mode, wherein the proximity sensor is inactive, and a hands-free mode, wherein the magnetically latching valve is toggled between its opened and closed positions in response to the proximity sensor, subject to being over-ridden by the output signal and logical control. In a third embodiment, the present invention provides a faucet comprising a spout, a touch control disposed within the spout, and a passageway conducting water flow through the spout. An electrically operable valve is disposed within the passageway. A logical control toggles the electrically operable valve when the touch control is touched and released within a period of time less than a predetermined threshold, but does not toggle the electrically operable valve when the touch control is touched for a period longer than the predetermined threshold. In a fourth embodiment, the present invention provides a capacitive touch control for a faucet having an electrically operable valve that is toggled in response to a toggle signal, the touch control comprising an electrode and a logical control that generates the toggle signal when the touch control is touched and released within a period of time less than a predetermined threshold, but which does not generate a toggle signal when the touch control is touched for a period longer than the predetermined threshold. | 20040114 | 20051108 | 20050714 | 58548.0 | 1 | LEE, KEVIN L | CAPACITIVE TOUCH ON/OFF CONTROL FOR AN AUTOMATIC RESIDENTIAL FAUCET | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,757,440 | ACCEPTED | Fishing float for positioning, detecting fish catch and lighting | An inductive device for fishing. The device includes an inductive circuit board, an inductive coil, an inductive shaft and a spring. The device includes of a lighting circuit board, a plurality of LEDs and a pedestal. In the process of sea fishing, since the float base is designed with a flat bottom, it is maintained at a fixed place to indicate where the fish hook is without being driven back to the shore by waves. The inductive shaft while being pulled down by a caught fish, will leave the induced range of inductive coil, at this moment, and the central LEDs will emit red light and the out-border blue LEDs will continue to light. If there is no catch of fish on the fish hook, the central LEDs will not emit red light, but the out-border LEDs will continue to emit blue light. | 1-8. (canceled) 9. A fishing float comprising: a base having a round shape, an inductive device housed in the base, the base includes a central hollow post, an inductive coil of the inductive device encircles the central hollow post, the central hollow post is extended out of the base and forms a connecting rod, and an inductive shaft is housed therein; a top lid configured as a round casing comprises a transparent material; a lighting device comprises a central light-emitting diode and surrounding light-emitting diodes emitting light color different from that of the central light-emitting diode, the light-emitting diodes are visible through the top lid; a lock bolt includes an inner thread configured to lock with the connecting rod; a waterproof washer positioned between the top lid and the base to prevent water from entering the fishing float; a battery compartment housed in a space between the base and the top lid, the battery compartment is configured to receive a power source to power the lighting device and the inductive device; the inductive device is mounted under the battery compartment and provides the induced signal of a fish catch; and an end of the inductive shaft that extends out of the lock bolt is securable to a fishing hook and line, when the inductive shaft is pulled by a fish the inductive coil activates the central light-emitting diode of the lighting device, which indicates to the user that a fish is pulling at the fishing float. 10. The fishing float as claimed in claim 9, wherein the base comprises a flat bottom. 11. The fishing float as claimed in claim 9, wherein the lighting device comprises a lighting circuit board 601, the light-emitting diodes and a pedestal, the light-emitting diodes are linked to the lighting circuit board and the light-emitting diodes extend out of respective holes on the pedestal so that the light emitting diodes are visible through the top lid, and the pedestal holds the lighting circuit board. 12. The fishing float as claimed in claim 11, wherein the central light-emitting diode emits red light and the light-emitting diodes surrounding the central light-emitting diode emit blue light, with the lighting of the central light-emitting diode indicting that a fish is pulling at the fishing float. 13. The fishing float as claimed in claim 9, wherein the inductive device comprises an inductive circuit board, the inductive coil, the inductive shaft and a spring, the inductive device is housed in a compartment of the base, the inductive shaft and the springs are mounted in the connecting rod with an end of the inductive shaft extending out of the lock bolt, and the lower end of the inductive shaft is configured to connect to hook and line. 14. The fishing float as claimed in claim 13, wherein the size and type of the spring correlates to the weight of the fish that is to be caught. 15. The fishing float as claimed in claim 9, wherein the connecting rod includes outer threads configured to receive the lock bolt. | FIELD OF THE INVENTION This invention related to an improvement of fish float, in particular, the float base is design with a flat bottom which keeps the float never returning to shore. The bright light it emits provides the fishing man an easy identification of where the fish hook is and accurately knowing whether a fish is caught or not without aid of the night vision light. BACKGROUND OF THE INVENTION Fishing is one of the best leisure activities to cultivate the patience. The fishing man has to wait with long quiet patience the fish to bite the bait on the fish hook; it is dull and tasteless long waiting. At the moment the fish is being hooked, the exciting pleasure is beyond description, this is critical reason most people like fishing. The float and night vision light are necessities for the night fishing even in pond fishing, sea fishing and river fishing which provide the fishing man the indication of fish catch and lighting. There are diverse floats and night vision lights available for use in fishing independently or in combination for the fishing man to see clearly the response of float. However, most floats are designed with round bottom, easy for the wave to drive them back to sea shore. For poor sight fishing man, if the float is too far away and the night vision light runs out, there is no advance warning signal to indicate whether the fish is being caught or not, he losses the chance in vain. Furthermore, the waste night vision light is hard to dispose of, it becomes an environmental problem. Since the prior art of induced float is unable to provides positioning and identification of fish catch, it requires the aid of the night vision light. Because these two are used independently, not in combination, no way to satisfy the desire the fishing man asks for, there is room for improvement. SUMMARY OF INVENTION The main object of this invention is to provide a float for easy positioning and bright lighting to reveal an early signal of fish catch without the aid of the night vision light. The main improvement is to add to the float the inductive device and the lighting device along with base and top lid. The inductive device comprises the inductive circuit board, the inductive coil, the inductive shaft and the spring; the lighting device contains the light circuit board, a plurality of LEDs and pedestal. The base bottom is a flat design. This combination is suitable for pond fishing and sea fishing. Because the flat bottom always keep the float at a fixed place, never permitting the wave to drive back to shore. While the fish is biting the bait, the inductive shaft is being pulled down and leaves the induced range of the inductive coil. At this instant, the central LED emit the red light and the out-border LEDs continue the blue light. In other words, if not fish biting, there is only blue light visible, no red light at all. The flat bottom design and the change of light colors (a combination of blue light with the red light) serve a warning signal showing the moment a fish is biting the bait on the fish hook. It also works as the lighting source. The invention is explained in great detail with the aid of embodiments as illustrated in the attached drawings. BRIEF DESCRIPTION OF DRAWING FIG. 1 shows the disassembly of the float of this invention. FIG. 2 shows the enlarged disassembly of the float of this invention. FIG. 3 shows the appearance of the complete assembly of the float of the invention. DETAIL DESCRIPTION OF THE INVENTION Please refer to FIGS. 1 and 2; the float (1) consists of a base (10), a top lid (20), a lock bolt (30), a waterproofing washer (40), a battery compartment (50), a lighting device (60) and an inductive device (70). In which the base (10) is round house separated into empty compartment (101). The central hollow post (102) forms a connecting rod (103) at the lower end. Of the base (10) to link the inductive coil (702). The lock bolt (30) has the inner thread to be locked on out thread of the connecting rod (103). Because the base bottom is a flat design, it is always keeping floating at a fixed place on the seas away from the sea shore. The top lid (20) is a round casing made of the transparent material so the red lights or the blue lights emitted from the LEDs (602) of the lighting device (60) are visible clearly. The lock bolt (30) has the inner thread to be locked on the connecting rod (103). The waterproofing washer (40) sits between the top lid (20) and the base (10) to keep the water from entering into the base. The battery compartment (50) is housed in the space formed by the top lid (20) and the base (10). The battery is the power source for the lighting device (60) and the inductive device (70). The lighting device (60) is mounted on the top of the battery compartment (50). The lighting device comprises the lighting circuit board (601), a plurality of LEDs (602) and the pedestal (603). The lighting circuit board (601) links a plurality of LEDs (602) in two colors, red and blue. The central protruded LED is red which is activated while the fish is biting. The blue LEDs surround the red LED serving the lighting. The pedestal (603) has a plurality of holes (604) permitting the LEDs (602) extending out of the holes (604) so the red or blue lights are visible outside of the top lid (20). The inductive device (70) is placed under the battery compartment (50), consisting of inductive circuit board (701), the inductive coil (702), the inductive shaft (703) and spring (704). The circuit board (701) is housed in the empty compartment (101) in the base (10). The inductive coil (702) encircles the central post (102). The inductive shaft (703), the spring (704) and the connecting rod (103) will be held together by the lock bolt (30) but one end of the inductive (704) will extend out of the lock bolt (30) but prevent them from falling off the lock bolt (30). The size of the spring (704) shall be inline with the catch fish weight the fishing man intends to catch. The connecting rod (703) links to the hook and bait. As shown in FIG. 3, this float (1) of this invention renders easy positioning, identifying the fish catch and lighting. In practice, the float (1) of this invention is always floating at a fixed place on the seas away from the sea shore. While the fish is biting the bail on the hook, the inductive shaft (703) is being pulled down from the inductive device (70), and leaves the induced range of the inductive coil (702). The central LED (602) on the lighting device (60) will emits the red light and the LEDs (602) surrounding the lighting device (60) will continue emitting blue light. If no fish biting, no red except the blue light from the LEDs (602) of the lighting device (60). Since the base (10) is designed with the flat bottom, it is always buoyed up at a fixed place away from the sea shore. The different light combination (blue lights plus red light) coming out of the LEDs (602) of the lighting device (60) give the fishing man a advanced warning signal indicating the fish is biting or the necessary lighting in the dark. Viewing from the above statement, it is learned that the float provided in this invention for easy positioning, identifying the fish catch and lighting is a technical break through, an vital improvement from the prior art. It is simple, practicable, and innovative, justified for the grand of new patent. | <SOH> BACKGROUND OF THE INVENTION <EOH>Fishing is one of the best leisure activities to cultivate the patience. The fishing man has to wait with long quiet patience the fish to bite the bait on the fish hook; it is dull and tasteless long waiting. At the moment the fish is being hooked, the exciting pleasure is beyond description, this is critical reason most people like fishing. The float and night vision light are necessities for the night fishing even in pond fishing, sea fishing and river fishing which provide the fishing man the indication of fish catch and lighting. There are diverse floats and night vision lights available for use in fishing independently or in combination for the fishing man to see clearly the response of float. However, most floats are designed with round bottom, easy for the wave to drive them back to sea shore. For poor sight fishing man, if the float is too far away and the night vision light runs out, there is no advance warning signal to indicate whether the fish is being caught or not, he losses the chance in vain. Furthermore, the waste night vision light is hard to dispose of, it becomes an environmental problem. Since the prior art of induced float is unable to provides positioning and identification of fish catch, it requires the aid of the night vision light. Because these two are used independently, not in combination, no way to satisfy the desire the fishing man asks for, there is room for improvement. | <SOH> SUMMARY OF INVENTION <EOH>The main object of this invention is to provide a float for easy positioning and bright lighting to reveal an early signal of fish catch without the aid of the night vision light. The main improvement is to add to the float the inductive device and the lighting device along with base and top lid. The inductive device comprises the inductive circuit board, the inductive coil, the inductive shaft and the spring; the lighting device contains the light circuit board, a plurality of LEDs and pedestal. The base bottom is a flat design. This combination is suitable for pond fishing and sea fishing. Because the flat bottom always keep the float at a fixed place, never permitting the wave to drive back to shore. While the fish is biting the bait, the inductive shaft is being pulled down and leaves the induced range of the inductive coil. At this instant, the central LED emit the red light and the out-border LEDs continue the blue light. In other words, if not fish biting, there is only blue light visible, no red light at all. The flat bottom design and the change of light colors (a combination of blue light with the red light) serve a warning signal showing the moment a fish is biting the bait on the fish hook. It also works as the lighting source. The invention is explained in great detail with the aid of embodiments as illustrated in the attached drawings. | 20040115 | 20060523 | 20050721 | 61679.0 | 0 | ROWAN, KURT C | FISHING FLOAT FOR POSITIONING, DETECTING FISH CATCH AND LIGHTING | SMALL | 0 | ACCEPTED | 2,004 |
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10,757,684 | ACCEPTED | Coated metal substrate | A coated metal substrate useful for carrying an exhaust emission treatment catalyst such as a three-way conversion catalyst for use with small engine platforms. The coated metal substrate comprises a metal such as a stainless steel, a carbon steel, a FeCr alloy, Hastelloy and the like. The coating on the metal substrate comprises an alumina silicate having alumina particles impregnated therein. The coating is applied using a liquid dispersion containing an aluminum silicate and the alumina particles are dispersed into the aluminum silicate coating while the coating is still wet. The coated metal substrate is then calcined. Thereafter, a washcoat containing an engine exhaust treatment catalyst may be applied to the surface of the coated metal substrate. | 1. A coated metal substrate for use in the catalytic reduction of engine exhaust emissions comprising a metal substrate having an alumina-silicate coating thereon, said alumina-silicate coating having alumina particles dispersed therein. 2. The substrate of claim 1 further comprising at least one top layer comprising an engine exhaust treatment catalyst. 3. The substrate of claim 2 wherein the catalyst comprises a three-way conversion catalyst. 4. The substrate of claim 1 wherein the metal substrate comprises a metal selected from the group consisting of a stainless steel, a carbon steel, titanium, a FeCr alloy and Hastelloy. 5. The substrate of claim 4 wherein the metal substrate comprises a stainless steel. 6. The substrate of claim 1 wherein the alumina particles have a particle size in the range of about 5 to about 15 microns. 7. The substrate of claim 6 wherein the alumina particles have a particle size in the range of 6 to 9 microns. 8. The substrate of claim 1 wherein the alumina particles are present in an amount of about 0.1 to about 0.5 g/in2 of the alumina-silicate coating. 9. The substrate of claim 1 wherein the metal substrate is employed in the form of an expansion cone or exhaust gas silencer. 10. The substrate of claim 9 wherein the expansion cone has a length of about 100 to about 300 mm, a diameter ranging from about 30 to about 100 mm, a thickness of about 0.5 to about 3 mm and an inside surface area of about 0.03 to about 0.06 m2. 11. A method for preparing a coated metal substrate for use in the catalytic reduction of engine exhaust emissions comprising the steps of: (a) coating a metal substrate with a liquid dispersion containing an aluminum silicate; (b) impregnating the coated metal substrate resulting from step (a) with alumina particles, while the aluminum silicate coating on the metal substrate is still wet; and (c) calcining the coated metal substrate resulting from step (b). 12. The method of claim 11 wherein step (c) is carried out at a temperature of about 350 to about 550° C. for about 0.25 to about 2 hours. 13. The method of claim 11 further comprising applying a washcoat comprising an engine exhaust treatment catalyst to the coated metal substrate resulting from step (c). 14. The method of claim 13 wherein the catalyst comprises a three-way conversion catalyst. 15. The method of claim 11 wherein the metal substrate comprises a metal selected from the group consisting of a stainless steel, a carbon steel, titanium, a FeCr alloy and Hastelloy. 16. The method of claim 15 wherein the metal substrate comprises a stainless steel. 17. The method of claim 11 wherein the alumina particles have a particle size in the range of about 5 to about 15 microns. 18. The method of claim 17 wherein the alumina particles have a particle size in the range of 6 to 9 microns. 19. The method of claim 11 wherein the alumina particles are present in an amount of about 0.01 to about 0.5 g/in2 of the aluminum silicate coating. 20. The method of claim 11 wherein the metal substrate is employed in the form of an expansion cone or exhaust gas silencer. 21. The method of claim 19 wherein the expansion cone has a length of about 200 to about 300 mm, a diameter ranging from about 30 to about 100 mm, a thickness of about 0.5 to about 3 mm and an inside surface area of about 0.03 to about 0.06 m2. 22. The method of claim 11 wherein the liquid dispersion comprises the following components in the indicated amounts: component amount, wt. % sodium potassium aluminum silicate about 40 to about 45 water about 35 to about 40 acrylic copolymer about 1 to about 5 chromia titania frit about 1 to about 5 aluminum oxide about 1 to about 5 potassium hydroxide about 1 to about 5 amorphous silica about 1 to about 5 cobalt oxide about 1 to about 5 23. The method of claim 11 wherein the liquid dispersion comprises the following components in the indicated amounts: component amount, wt. % silicon carbide about 45 to about 50 water about 20 to about 26 aluminum phosphate about 10 to about 15 amorphous silicon oxide binders about 2 to about 6 boric acid about 1 to about 3 ethyl alcohol about 3 to about 7 mullite about 4 to about 6 | FIELD OF THE INVENTION The invention relates to a coated metal substrate useful for carrying an engine exhaust treatment catalyst. BACKGROUND OF THE INVENTION Small internal combustion engines, especially two-stroke and four-stroke spark ignition engines, are used to provide power to a variety of machinery, e.g., gasoline-powered lawn mowers, chain saws, leaf blowers, string cutters, leaf blowers, motor scooters, motorcycles and the like. Such engines provide a severe environment for a catalytic exhaust treatment apparatus. This is due to the fact that in small engines, the exhaust gas contains a high concentration of unburned fuel and unconsumed oxygen. Additionally, the vibrational force in a two-stroke engine can be three or four times that of a four-stroke engine. For example, vibrational accelerations of 70 to 90 gravitational acceleration at 150 Hertz have been reported for small internal combustion engines. The harsh vibration and exhaust gas temperature conditions associated with small internal combustion engines lead to several modes of failure in the exhaust gas catalytic treatment apparatus, including failure of the mounting structure by which a catalyst member is secured in the apparatus and consequential damage or destruction of the catalyst member due to the mechanical vibration and to flow fluctuation of the exhaust gas under high temperature conditions. The catalyst member usually comprises a ceramic-like carrier member typically made of e.g., cordierite, mullite, etc., on which an exhaust treatment catalytic material is coated. The ceramic-like material is subject to cracking and pulverization due to excessive vibration. Metal carrier members, i.e., metal substrates, are obvious replacements for the ceramic-like materials, but have their own problems as brought out below. In the near future, small internal combustion engines will become subject to stringent federal and state emission control regulations. Accordingly, these small engines will require exhaust emission control systems analogous to those currently employed for control of automotive emissions. For the exhaust emission control systems to be used for the small internal combustion engines typically a metal substrate (also referred to in the prior art as a metal carrier member) will be coated with an exhaust control treatment catalyst such as a three-way conversion (“TWC”) catalyst that will control the emissions of hydrocarbons, carbon monoxide and nitrogen oxides. The challenge has been to impart the required physical properties to the metal substrate that will permit the catalyst to withstand high temperature conditions with severe vibration and poisons from oil and ash over a wide variety of small engine platforms with limited lives and the need for such small engine platforms to operate under a wide range of air/fuel ratios and space velocities. Major differences in the coefficients of thermal expansion of a precious metal catalyst and the metal substrate exacerbate this problem. The exhaust control emission catalyst materials are typically used in particulate form with particles in the micron-sized range, e.g., 10 to 20 microns in diameter, so that they can be formed into a slurry and applied as a washcoat on the carrier member. Known TWC catalysts that exhibit good activity and long life comprise one or more platinum group metals (e.g., platinum or palladium, rhodium, ruthenium and iridium) disposed on a high surface area, refractory oxide support, e.g., a high surface area alumina coating. The principal problem associated: with the coating of metal substrates with an exhaust emission control treatment catalyst such as a TWC catalyst is adherence of the catalyst to the metal substrate over the wide range of conditions to which the catalyst-coated metal substrate will be exposed during operation of the small engine platform. OBJECT OF THE INVENTION It is an object of the invention to provide a coating composition and a method for coating a metal substrate that is effective for anchoring an exhaust emission control treatment catalyst to the metal substrate. SUMMARY OF THE INVENTION The invention relates to a coated metal substrate for use in the catalytic reduction of engine exhaust emissions comprising a metal substrate and an alumina-silicate coating on the metal substrate, said coating having alumina particles dispersed therein. DETAILS OF THE INVENTION For the purposes of the present invention, the metal substrate may be comprised of a metal such as stainless steel, a carbon steel, titanium, a FeCr alloy or Hastelloy. Hastelloy is a non-trademarked alloy whose major components are nickel-chromium and molybdenum and containing minor components comprising cobalt, iron and tungsten. Typically, the metal substrates to be used for the small engine platforms will be present in the form of an expansion cone or exhaust gas silencer, having a length of about 100 to about 300 mm, a diameter ranging from about 30 to about 100 mm, a thickness of about 0.5 to about 3 mm and an inside surface area of about 0.03 to about 0.06m2. The bond coat on the surface of the metal substrate comprises an alumina-silicate composition that contains alumina particles dispersed therein. It has been found that an alumina-silicate composition adheres very well to the surface of the metal substrate. However, the surface of the alumina-silicate bond coat is quite smooth and exhaust emission treatment catalyst compositions do not adhere too well to the surface of the bond coat, particularly under the conditions to which the coated metal substrate will be exposed during operation of the small engine platform. It was found that when particles of alumina were dispersed in the bond coat while it was still wet, after calcination of the resultant coated metal substrate, the exhaust emission treatment catalyst adhered quite well to the coated metal substrate under all operating conditions associated with the small engine platforms. The procedure for applying the bond coat and for dispersal of the alumina particles in the bond coat is relatively simple. If necessary, the metal substrate is sandblasted to form a rough surface and remove any unwanted particles; thereafter, the sandblasted metal substrate may be washed in 30% acetic acid followed by a water rinse. The bond coat composition comprising an aqueous dispersion in which the major component is an aluminum silicate is then applied to the clean surface of the metal substrate, e.g., by dipping, brushing, sponge roller, air gun spraying, etc. Thereafter, alumina particles are applied, e.g., by dipping, brushing, etc., to the coated metal substrate while the bond coat on the metal substrate is still wet. Loose alumina particles may then be removed from the coated surface, e.g., by a gentle stream of air, by tapping on a hard surface, etc., and the resultant coated metal substrate is thereafter calcined. Subsequent to calcination, an exhaust emission treatment catalytic washcoat containing one or more precious metals such as platinum, palladium, rhodium, etc., may then be applied to the surface of the coated metal substrate by conventional methods well known in the prior art followed by drying and calcination of the catalyst-loaded coated metal substrate. The process for preparing the coated metal substrate of the invention may be summarized as involving the following steps: (a) coating a metal substrate with a liquid dispersion containing an aluminum silicate; (b) impregnating the coated metal substrate resulting from step (a) with alumina particles, while the aluminum silicate coating on the metal substrate is still wet; and (c) calcining the coated metal substrate resulting from step (b). Liquid dispersions containing an aluminum silicate are well known in the prior art and are commercially available. A suitable aluminum silicate dispersion is the following composition: component amount, wt. % sodium potassium aluminum silicate about 40 to about 45 water about 35 to about 40 acrylic copolymer about 1 to about 5 chromia titania frit about 1 to about 5 aluminum oxide about 1 to about 5 potassium hydroxide about 1 to about 5 amorphous silica about 1 to about 5 cobalt oxide about 1 to about 5 Another suitable aluminum silicate dispersion is the following composition: component amount, wt. % silicon carbide about 45 to about 50 water about 20 to about 26 aluminum phosphate about 10 to about 15 amorphous silicon oxide binders about 2 to about 6 boric acid about 1 to about 3 ethyl alcohol about 3 to about 7 mullite about 4 to about 6 The alumina particles are applied in step (b) of the process in the form of a powder wherein the particles have a particle size in the range of about 5 to about 15 microns, preferably 6 to 9 microns. The alumina particles are applied in an amount of about 0.01 to about 0.5 g/in2 of the aluminum silicate coating that was applied in step (a) of the process. Step (c), i.e., the calcination, is carried out at a temperature of about 350 to about 550° C. for about 0.25 to about 2 hours. A washcoat containing an engine exhaust treatment catalyst may then be applied (e.g., by spraying, dipping, rolling, etc.) to the coated metal substrate resulting from step (c), followed by air drying at about 60 to about 100° C. for about 0.5 to about 2 hours and subsequent calcination at a temperature of about 350 to about 550° C. for about 0.25 to about 2 hours. The following nonlimiting examples shall serve to illustrate the embodiments of the present invention. Unless otherwise indicated, all parts and percentages are on a weight basis. EXAMPLE 1 The metal substrate employed in this example was an expansion cone comprised of 1.3 mm gauge 309 stainless steel. The expansion cone had a length of 172 mm, an inside diameter ranging from 40.2 mm to 66.4 mm and a calculated area of 0.0288 m2. The expansion cone was sandblasted, washed with 30% acetic acid and rinsed with distilled water. The cleaned expansion cone was then air gun-sprayed with an aluminum-silicate dispersion having the following composition: component amount, wt. % sodium potassium aluminum silicate about 40 to about 45 water about 35 to about 40 acrylic copolymer about 1 to about 5 chromia titania frit about 1 to about 5 aluminum oxide about 1 to about 5 potassium hydroxide about 1 to about 5 amorphous silica about 1 to about 5 cobalt oxide about 1 to about 5 The sprayed expansion cone was then calcined at a temperature of 450° C. for a period of 30 minutes. Laboratory thermal shock testing indicated that the alumina-silicate coating readily survives temperature cycling in excess of 1000° C. After calcination, the cone was cooled to room temperature and a washcoat comprised of an engine exhaust treatment catalyst was then applied at a target rate of 1.75 g per cone using a hand held air spray gun so as to apply 0.07 g precious metal per cone. The washcoat consisted of an aqueous slurry (35 wt. % solids) of an engine exhaust treatment catalyst consisting of the following components: component amount, g/in3 high surface area alumina 0.61 CeZr coprecipitated composite 0.31 barium acetate 0.04 zirconium acetate 0.025 Pt (as ammonium hydroxide) 0.037 Pd (as nitrate) 0.0037 The resultant cone was then air dried at 80° for 1 hour and then calcined at 450° C. for 30 minutes. No further studies were conducted on the coated expansion cone since the wash coat slurry did not adhere to the surface of the alumina-silicate coated expansion cone. EXAMPLE 2 Example 1 was repeated with the following exceptions: The expansion cone was coated with the same aluminum-silicate dispersion by means of a sponge roller rather than by air gun spraying. The coated cone was then dipped into alumina powder having a particle size range of 2-15 microns) while the surface of the cone was still wet with the aluminum-silicate dispersion. The cone was then tapped on a hard surface to remove loose alumina particles followed by calcination at a temperature of 450° C. for a period of 30 minutes. The coated cone contained about 0.3 g of the alumina particles. Following calcination, the cone was cooled to room temperature and the same washcoat as employed in Example 1 was applied to the coated cone at a target rate of 1.75 g per cone using a hand held air spray gun so as to apply 0.07 g precious metal per cone. The resultant cone was then air dried at 80° for 1 hour and then calcined at 450° C. for 30 minutes. Laboratory thermal shock testing of the coated cone of Example 2 indicated that the alumina-silicate coating readily survives temperature cycling in excess of 1000° C. The coated cone of Example 2 was close-coupled engine aged on a stationary generator for a period of about 300 hours. Visual inspection of the aged cone showed no significant physical deterioration of the coating. | <SOH> BACKGROUND OF THE INVENTION <EOH>Small internal combustion engines, especially two-stroke and four-stroke spark ignition engines, are used to provide power to a variety of machinery, e.g., gasoline-powered lawn mowers, chain saws, leaf blowers, string cutters, leaf blowers, motor scooters, motorcycles and the like. Such engines provide a severe environment for a catalytic exhaust treatment apparatus. This is due to the fact that in small engines, the exhaust gas contains a high concentration of unburned fuel and unconsumed oxygen. Additionally, the vibrational force in a two-stroke engine can be three or four times that of a four-stroke engine. For example, vibrational accelerations of 70 to 90 gravitational acceleration at 150 Hertz have been reported for small internal combustion engines. The harsh vibration and exhaust gas temperature conditions associated with small internal combustion engines lead to several modes of failure in the exhaust gas catalytic treatment apparatus, including failure of the mounting structure by which a catalyst member is secured in the apparatus and consequential damage or destruction of the catalyst member due to the mechanical vibration and to flow fluctuation of the exhaust gas under high temperature conditions. The catalyst member usually comprises a ceramic-like carrier member typically made of e.g., cordierite, mullite, etc., on which an exhaust treatment catalytic material is coated. The ceramic-like material is subject to cracking and pulverization due to excessive vibration. Metal carrier members, i.e., metal substrates, are obvious replacements for the ceramic-like materials, but have their own problems as brought out below. In the near future, small internal combustion engines will become subject to stringent federal and state emission control regulations. Accordingly, these small engines will require exhaust emission control systems analogous to those currently employed for control of automotive emissions. For the exhaust emission control systems to be used for the small internal combustion engines typically a metal substrate (also referred to in the prior art as a metal carrier member) will be coated with an exhaust control treatment catalyst such as a three-way conversion (“TWC”) catalyst that will control the emissions of hydrocarbons, carbon monoxide and nitrogen oxides. The challenge has been to impart the required physical properties to the metal substrate that will permit the catalyst to withstand high temperature conditions with severe vibration and poisons from oil and ash over a wide variety of small engine platforms with limited lives and the need for such small engine platforms to operate under a wide range of air/fuel ratios and space velocities. Major differences in the coefficients of thermal expansion of a precious metal catalyst and the metal substrate exacerbate this problem. The exhaust control emission catalyst materials are typically used in particulate form with particles in the micron-sized range, e.g., 10 to 20 microns in diameter, so that they can be formed into a slurry and applied as a washcoat on the carrier member. Known TWC catalysts that exhibit good activity and long life comprise one or more platinum group metals (e.g., platinum or palladium, rhodium, ruthenium and iridium) disposed on a high surface area, refractory oxide support, e.g., a high surface area alumina coating. The principal problem associated: with the coating of metal substrates with an exhaust emission control treatment catalyst such as a TWC catalyst is adherence of the catalyst to the metal substrate over the wide range of conditions to which the catalyst-coated metal substrate will be exposed during operation of the small engine platform. | <SOH> SUMMARY OF THE INVENTION <EOH>The invention relates to a coated metal substrate for use in the catalytic reduction of engine exhaust emissions comprising a metal substrate and an alumina-silicate coating on the metal substrate, said coating having alumina particles dispersed therein. detailed-description description="Detailed Description" end="lead"? | 20040114 | 20070918 | 20050714 | 62519.0 | 0 | HAILEY, PATRICIA L | COATED METAL SUBSTRATE | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,757,789 | ACCEPTED | Multiple connection management system | An apparatus, program product and method for managing a number of physical connections to a peripheral device. A multipath driver provides a logical connection interface to a client. This interface allows the client to efficiently access the peripheral device over one or more of the physical connections. In so doing, the logical connection interface associates connections with a primary connection, deletes inactive connections from memory, as well as updates and uses a list of active connections to seamlessly route data to the peripheral device. | 1. An apparatus comprising: a processor; and a multipath device driver configured to execute on the processor and to manage a plurality of physical connections to a peripheral device, the multipath device driver providing a logical connection interface configured to provide client access to the peripheral device over at least one of the plurality of physical connections. 2. The apparatus of claim 1, wherein multipath device driver includes a device driver for each of the plurality of physical connections, and coupled to the multipath device driver. 3. The apparatus of claim 1, wherein the multipath device driver is configured to manage a list including the plurality of physical connections. 4. The apparatus of claim 3, wherein the multipath device driver is further configured to manage a second list including information pertaining to active connections of the plurality of physical connections. 5. The apparatus of claim 4, wherein the second list includes information pertaining to a status of each of the plurality of connections. 6. The apparatus of claim 1, wherein the multipath device driver initiates determining an alternative connection in response to a failed connection. 7. The apparatus of claim 6, wherein the multipath device driver determines the alternative connection by accessing a list of alternative connections. 8. The apparatus of claim 1, wherein the multipath device driver initiates deleting connection data from the peripheral device. 9. The apparatus of claim 1, wherein the multipath device driver initiates deleting the connection data by communicating with the peripheral device over another of the plurality of connections. 10. The apparatus of claim 1, wherein the multipath device driver initiates writing connection data to the peripheral device. 11. The apparatus of claim 1, wherein the multipath device driver initiates associating a first device driver with a second device driver. 12. The apparatus of claim 1, wherein the multipath device driver initiates searching a list for an identifier indicative of the peripheral device to determine a primary connection. 13. The apparatus of claim 1, wherein the multipath device driver initiates placing a lock on a device driver to prevent another device driver from searching a list. 14. The apparatus of claim 1, wherein the multipath device driver initiates designating a connection as a primary connection. 15. The apparatus of claim 1, wherein the multipath device driver is created by a primary device driver. 16. The apparatus of claim 15, wherein the primary device driver creates the multipath device driver in response to detecting a new connection associated with the peripheral device. 17. An apparatus comprising: a processor; and a device driver executing on the processor and configured to manage a plurality of physical connections to a peripheral device, the device driver providing a logical connection interface configured to create a list including data associated with at least one active connection of a plurality of connections connecting a computer to the peripheral device, and to use the list to automatically route communications from the computer to the peripheral device. 18. The apparatus of claim 17, wherein the device driver is configured to use the list to route the communications to a second connection on the list in the event that a first connection fails. 19. The apparatus of claim 17, wherein the device driver is configured to remove the data associated with the at least one active connection from the list in response to the at least one active connection failing. 20. The apparatus of claim 17, wherein the device driver is configured to create a second list including information pertaining to all of the plurality of connections. 21. An apparatus comprising: a processor; and a multipath device driver executing on the processor and configured to manage a plurality of physical connections to a peripheral device, the multipath device driver providing a logical connection interface configured to receive input associated with removing from memory of the peripheral device information pertaining to an undesired connection of the plurality of connections connecting a computer to the peripheral device, and to remove the information from the peripheral device. 22. The apparatus of claim 21, wherein the multipath device driver is further configured to determine an alternative connection in communication with the peripheral device. 23. The apparatus of claim 21, wherein the multipath device driver is further configured to remove the information from the peripheral device using the alternative connection in communication with the peripheral device. 24. A method for managing a plurality of physical connections from a computer to a peripheral device, the method comprising: creating a multipath device driver comprising a logical connection to a peripheral device coupled to a computer over a plurality of physical connections; and accessing the peripheral device using the multipath device driver. 25. The method of claim 24, further comprising adding a new device driver associated with the multipath device driver in response to detecting a new connection between the peripheral device and the computer. 26. The method of claim 24, wherein accessing the peripheral device using the multipath device driver further includes accessing a memory. 27. The method of claim 24, wherein accessing the peripheral device using the multipath device driver further includes determining an alternative connection to the peripheral device in response to detecting a failed connection. 28. The apparatus of claim 27, determining an alternative connection to the peripheral device in response to detecting a failed connection further includes accessing a list of active connections. 29. The method of claim 24, wherein accessing the peripheral device over the multipath device driver further includes deleting connection data from the peripheral device. 30. The method of claim 29, wherein deleting connection data from the peripheral device further includes communicating with the peripheral device over another of the plurality of connections. 31. The method of claim 24, wherein accessing the peripheral device over the multipath device driver further includes writing connection data to the peripheral device. 32. The method of claim 24, wherein creating the multipath device driver further includes associating a new device driver with a primary device driver, wherein the primary device driver is associated with the multipath device driver. 33. The method of claim 24, wherein creating the multipath device driver further includes updating a list including active connections to the peripheral device. 34. The method of claim 24, wherein creating the multipath device driver further includes updating a list including status information pertaining to the plurality of connections. 35. The method of claim 24, wherein creating the multipath device driver further includes searching a list for an identifier associated with the peripheral device. 36. The method of claim 24, wherein creating the multipath device driver further includes placing a lock on an object to prevent the object from searching a list. 37. The method of claim 24, wherein creating the multipath device driver further includes reading identification data from the peripheral device to confirm an identity of a connection. 38. The method of claim 24, wherein creating the multipath device driver further includes creating a multipath driver in response to detecting a new connection associated with a different peripheral device. 39. The method of claim 24, wherein creating the multipath device driver further includes creating the multipath device driver using a primary device driver. 40. The apparatus of claim 37, wherein creating the multipath device driver further includes creating the multipath device driver in response to detecting a new connection associated the peripheral device. 41. The apparatus of claim 37, wherein creating the multipath device driver further includes using a new device driver associated with a new connection to prompt a primary device driver to create the multipath device driver, wherein the multipath device is associated with both the primary and new device drivers. 42. A method for managing a plurality of physical connections from a computer to a peripheral device, the method comprising: creating a list including data associated with at least one active connection of a plurality of connections connecting a computer to a peripheral device; and using the list to automatically route communications from the computer to the peripheral device. 43. The method of claim 42, wherein using the list further includes using the list to route the communications to a second connection in the event that the at least one active connection fails. 44. The method of claim 42, further comprising removing the data associated with the at least one active connection in response to the at least one active connection failing. 45. The method of claim 42, further comprising creating a list including information pertaining to all of the plurality of connections. 46. A method for managing a plurality of physical connections from a computer to a peripheral device, the method comprising: receiving input associated with removing from memory of a peripheral device information pertaining to an undesired connection of a plurality of connections connecting a computer to the peripheral device; and removing the information from the peripheral device. 47. The method of claim 46, wherein removing the information further includes determining an alternative connection in communication with the peripheral device. 48. The method of claim 47, wherein removing the information further includes using the alternative connection in communication with the peripheral device to remove the information from the peripheral device. 49. A program product, comprising: program code including a device driver configured to manage a plurality of physical connections to a peripheral device, the device driver providing a logical connection interface configured to provide client access to the peripheral device over at least one of the plurality of physical connections; and a signal bearing medium bearing the program code. 50. The program product of claim 49, wherein the signal bearing medium includes at least one of a recordable medium and a transmission-type medium. | FIELD OF THE INVENTION The present invention relates to computing systems, and more particularly, to computer software and hardware used to communicate between networked devices of computing systems. BACKGROUND OF THE INVENTION Effective computer operation requires the efficient reading and writing of data out to peripheral devices, such as storage disks. Fundamental to this read and write capability is the hardware connection that provides the physical pathway for communication with the peripheral device. Such a connection commonly comprises a fiber optic cable that couples to ports of both the computer and the peripheral device. As such, the cable comprises the communication link over which the read and write data is exchanged. For performance and reliability considerations, computer systems have been developed that use a number of cables to connect two devices. For example, a computer may write and read: data to and from a single disk storage unit using five or more cables. In one respect, using multiple cables to connect the same computer devices bolsters reliability. In the event that should one or more of the cables become disconnected or otherwise inoperable, another connection ideally remains available. A larger number of cables also provides increased bandwidth, allowing for more efficient data exchanges. Despite such processing and reliability advances, however, using redundant connections presents new challenges to computer performance. For example, existing systems are only configured to route data to a desired peripheral device using a single connection. The existing upper level programming of systems relies on the one-to-one relationship of a peripheral device to its respective cable connection in order to route data to the device. This is because the upper level programming sends a write/read command without regard to the connection. When writing data, for example, the upper level programs are configured only to “see” or otherwise process the address specific to the target disk unit. With the advent of redundant connections, a computer having a number of connections to the same disk unit must account for the existence of each cable connection in order to successfully read and write data. The status of each cable, for instance, whether a cable is reporting or not, deleted, added, etc., must be known. Otherwise, failure to separately track each connection can cause data to be written or read to or from an inappropriate device. Such miscommunication will result in file corruption. Furthermore, existing systems have relatively limited memory resources available to potentially store address, routing and other information pertaining to different communication paths. Accommodating multiple cable connections for each device must somehow not overburden available memory. Moreover, the time critical nature of computer processing requires that any routing scheme be sufficiently efficient to handle increasing workloads without delay. Therefore, a significant need exists for an improved manner of managing connections between hardware devices and a computer system. SUMMARY OF THE INVENTION The invention addresses these and other problems associated with the prior art by providing an apparatus, program product and method of managing a number of physical connections to a peripheral device. An embodiment consistent with the invention includes a multipath driver that provides a logical connection interface. This interface allows a client to efficiently access the peripheral device over one or more of the physical connections. For instance, a client user or system may read and write data to the peripheral device without regard to which actual physical connection is used to route the data. Instead, that physical connection is automatically and transparently determined by the multipath driver. These and other advantages and features, which characterize the invention, are set forth in the claims annexed hereto and forming a further part hereof. However, for a better understanding of the invention, and of the advantages and objectives attained through its use, reference should be made to the Drawings, and to the accompanying descriptive matter, in which there is described exemplary embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a computer system consistent with the invention. FIG. 2 is a block diagram of a computer in the system of FIG. 1. FIG. 3 is a block diagram of the operating system of FIG. 2 after a new connection is added. FIG. 4 is a flowchart illustrating an exemplary routine for locating a primary associated with a disk unit in the computer system of FIG. 1. FIG. 5 shows a series of exemplary steps configured to associate a new device driver with a primary located in FIG. 4. FIG. 6 is a flowchart illustrating an exemplary routine performed by the multipath driver of FIG. 3 for sequencing to another connection in response to a failed connection. FIG. 7 is a flowchart illustrating an exemplary routine for disassociating a connection from a disk unit in the computer system of FIG. 1. DETAILED DESCRIPTION The present invention provides an apparatus, program product and method of managing a number of physical connections to a peripheral device. An embodiment consistent with the invention includes a multipath driver that enables a client to efficiently access the peripheral device over one or more of the physical connections. The physical connection used to access the device is automatically and transparently determined by the multipath driver. In one sense, a multipath driver comprises a logical interface layer between the client/upper level programming and logic associated with each connection. That is, a multipath driver may comprise a new layer that preserves the “one device” interface for current hardware and software implementations, while at the same time providing an interface that maintains information specific to the individual connections to the peripheral device. This allows the upper level programming to accomplish functions such as read, write, reset, read-parameters, etc., while focusing only on the “one view” of the peripheral device provided by the multipath driver. The client and other upper level programming thus remain unburdened by the actual physical connections. By correlating multiple connections to a single peripheral device and allowing the connection to be treated as one entity, the multipath driver reduces the occurrence of data corruption. For instance, the multipath driver helps prevent the overlooking of a connection, or the improper association of a connection with a peripheral device. Also, additional connections may be added “on the fly” without requiring any shutdown/quiesce, etc. To this end, the multipath driver may include a list that includes pointers to only those object fields associated with available or otherwise desirable connections. By keeping a separate list of just the active connections, storage space is saved. Moreover, the more concise list reduces processing time and power needed to locate an appropriate connection. The multipath device additionally handles connection failures by removing the failed connection from the list, and by determining an alternative connection to the peripheral device. Of note, the transition to this alternative connection is accomplished seamlessly, or without any discernable delay to the client. Thus, computing operations remain uninterrupted in spite of the failed connection. These features of the active list and multipath driver thus avoid having to check the status of each device driver when determining a new route. These features also ensure an optimum number of retries and that all possible paths are tried. Deletion of failed connections from the list also frees up memory for other applications. Furthermore, the multipath driver continuously updates connection information to mitigate occurrences of data corruption and processing delay. For example, as connections are added and deleted per system specifications, a corresponding logical connection is automatically established. Moreover, processes of the present invention minimize the use of memory by deleting data pertaining to undesired connections. Turning to the Drawings, wherein like numbers denote like parts throughout the several views, FIG. 1 shows an exemplary computer system 10 configured to manage a number of physical connections 22 linking a computer 12 to a peripheral device 18. That is, the computer 12 of FIG. 1 couples to the peripheral device 18 using more than one cable or other connection. The system 10 manages these connections to enable efficient communication of computer commands and data. Such management includes data routing functions, as well as associating each of the connections 22 with a primary connection and/or a peripheral device 18 for client processing considerations. To this end, the computer 12 of the system 10 is configured to support a multipath driver that provides a logical connection interface to client software. This interface allows the client to efficiently access the peripheral device 18 over one or more of the physical connections 22. In so doing, the logical connection/multipath interface of the computer 12 associates connections with a primary connection, while updating and using a list of active connections to seamlessly route data to the peripheral device 18. In one embodiment, inactive connections are deleted from memory. As shown in FIG. 1, the system 10 includes a plurality of computers 12, 14 and 16 networked to each other and to peripheral devices 18 and 20. The exemplary peripheral devices of FIG. 1 include storage server logical units configured to both store and route data to and from networked computers 12, 14 and 16. Such storage server logical units include individually addressable disk units that each computer 12, 14 and 16 may read and write data from and to, respectively. An example of a server logical unit is an Enterprise Storage Server, such as is available from International Business Machines Corporation. Fiber optic cables 22 connect computers 12, 14 and 16 to the peripheral units 18 and 20. While FIG. 1 shows peripheral units 18 and 20 as server logical units, one skilled in the art should appreciate that an alternative, suitable peripheral device may comprise other networked hardware devices. Moreover, while connections 22 shown in FIG. 1 include fiber optic cables, suitable connections of other embodiments consistent with the invention may include other communication devices, to include wireless transmission equipment. Though not necessary for purposes of some embodiments consistent with the present invention, the system 10 of FIG. 1 supports clustering. Clustering generally refers to a computer system organization where multiple computers are networked together to cooperatively perform computer tasks. An important aspect of a computer cluster is that all of the computers in the cluster present a single image. Clustering is often used in relatively large, multi-user computer systems where high performance and reliability are of particular concern. For example, clustering is used to increase overall performance, since multiple computers can handle a larger number of tasks in parallel than a single computer otherwise could. Often, load balancing can be used to ensure that tasks are distributed fairly among computers to prevent individual computers from becoming overloaded. Clustering may also be used to provide redundancy, or fault tolerance, so that should any computer or connection fail, the operations previously performed by that computer or connection will be handled by other computers or connections in the cluster. In the specific context of FIG. 1, multiple connections 22 support communication between the clustered computer 12 and a peripheral unit 18 of the clustered system 10. As such, a number of connections 22 may comprise different communication paths to the computer 12 from the same disk unit of a server logical unit. These redundant connections 22 can provide improved system reliability and performance. In one exemplary embodiment, computers 12, 14 and 16 are implemented as iSeries computers from International Business Machines Corporation, and operating system 40 is implemented as an appropriate operating system incorporating clustering capabilities, such as the OS/400 operating system also available from IBM. The general use and configuration of clustering services in the exemplary environment is well known to one of ordinary skills in the art. It will be appreciated that the processes consistent with the present invention may be accomplished in systems other than those organized in a clustered configuration. It will further be appreciated that nomenclature other than that specifically used herein to describe the handling of computer tasks by a computer system may be used in other environments. Therefore, the invention should not be limited to the particular nomenclature used herein, e.g., as to protocols, requests, writing, reading, deleting, jobs, objects, etc. FIG. 2 shows an exemplary hardware configuration of the computer 12 of FIG. 1 configured to manage one or more physical connections to a peripheral device 18. Computer 12 generically represents, for example, any of a number of multi-user computers such as a network server, a midrange computer, a mainframe computer, etc. As such, the terms “node,” “system” and “computer” are sometimes used interchangeably throughout this specification. In any case, it should be appreciated that the invention may be implemented in other computers and data processing systems, e.g., in stand-alone or single-user computers such as workstations, desktop computers, portable computers, and the like, or in other programmable electronic devices (e.g., incorporating embedded controllers and the like). Computer 12 generally includes one or more system processors 24 coupled to a main storage 26 through one or more levels of cache memory disposed within a cache system 28. Furthermore, main storage 26 is coupled to a number of types of external devices via a system input/output (I/O) bus 35 and a plurality of interface devices, e.g., a workstation controller 34 and an I/O Processor 36, which respectively provide external access to one or more external networks (e.g., a cluster network interconnection), one or more workstations 14, and/or one or more storage devices, such as a storage server logical unit. Any number of alternate computer architectures may be used. To implement an apparatus, program product and method for managing connections consistent with the invention, computer 12 is illustrated as having resident in main storage 26 an operating system 40 implementing a plurality of objects 31, 41, 42 and 50 for managing connections to a peripheral devices 18. Objects comprise both data structures and operations, known collectively as methods. Methods access and manipulate data structures. Objects having identical data structures and common behavior can be grouped together into classes. Object structures include data and pointer fields. Pointers contain the addresses of other memory locations. Data fields embody information or other objects. While shown in the illustrated embodiments as an object, the multipath driver, device driver, and all other software components consistent with the invention are not limited to consisting of objects in other embodiments. As shown in FIG. 2, some of the objects 31, 41 and 42 of the operating system 40 may correspond to physical components of the computer 12 and/or computer system 10. For instance, the IOP 31 may correspond to I/O processor 36, which along with an adapter (not shown), communicates with the peripheral device 18. As such, the IOP 31 includes methods to access and manipulate the I/O processor 36. That is, the IOP 41 initiates processes associated with accessing the peripheral device 18 using the I/O processor 36. Similarly, the device driver 42 may correspond to, on a one-to-one basis, a physical connection in communication with peripheral device 18. The device driver 42 thus functions as a logical structure through which the operating system 40 manipulates information and processes associated with the respective cable connection. As shown in FIG. 2, the computer 12 thus has only one physical connection associated with the peripheral device 18. The storage manager 50 includes and otherwise communicates with other upper level programs responsible for managing disk assignments. That is, the storage management 50 is configured to assign, read and write commands and other data to disk units and other peripheral devices 18. In the single connection scenario of FIG. 2, the storage manager 50 sends and receives information to and from a device driver 42. The device driver 42 functions, in part, as an interface between the IOP 31 and the storage manager 50. For instance, the device driver 42 may read from the peripheral device 18 prior to its communication to the storage manager 50. Such data includes one or more identifiers associated with respective peripheral units, e.g., disk units. The storage manager 50 may use this identifier information when determining read/write assignments, for example. As is known in the art, the device driver 42 may additionally interface with a Logical Hardware Resource Information (LHRI) 41. The LHRI 41 addresses and processes user and system input to ensure, in one respect, consistent naming conventions between computers and systems. The LHRI 41 may additionally correspond to a physical HRI interface for receiving user input. As discussed below in greater detail, such input may include specifying removal of a connection from association with a peripheral device 18. One or more jobs or applications 46 are also illustrated in computer 12, each having access to the objects 31, 41, 42 and 50 and other features implemented within the operating system 40. It will be appreciated, however, that the functionality or features described herein may be implemented in other layers of software in computer 12, and that the functionality may be allocated among other programs, methods, computers or components in clustered computer system 10. Therefore, the invention is not limited to the specific software implementation described herein. The connection between the I/O processor 36 and the peripheral unit 18 of FIG. 2 may comprise one or more connections, such as the fiber optic cable shown in FIG. 1. The exemplary objects 31, 41 and 42 may each be particular to a single connection. As shown in FIG. 3, new such objects may be created for each additional connection added or otherwise associated with the same disk unit. More particularly, FIG. 3 shows the operating system 40 of the computer 12 of FIG. 2 with a plurality of connections to a single disk unit 60. In one sense, FIG. 3 illustrates the operating system 40 of FIG. 2 after two additional connections between the computer 12 and disk unit 60 are added. New connections 66 and 68 may be created when new cables are installed between the computer 12 and the same disk unit 60. As such, the disk unit 60 of FIG. 3 connects to the computer 12 with three connections that are logically represented by branching lines 64, 66 and 68. As shown in FIG. 3, the addition of each connection may prompt the creation of a new device driver, IOP and LHRI within the operating system 40 for each connection. As such, each device driver 42, 71 and 72 of operating system 40 may associate with a respective, physical connection 64, 66 and 68. Each device driver thus functions as a logical structure through which the operating system 40 manipulates information and processes associated with the respective cable connection. For reasons discussed in detail below, the device driver 42 associated with the first connection 64 to the disk unit 60 may include a primary flag 67 or other designator. Such a primary designator in the device driver 42 may assist with associating subsequently installed connections with the primary device driver 42 and the disk unit 60. Each connection 64, 66 and 68 has a respective IOP 41, 69 and 70. However, one skilled will appreciate that suitable IOP's may be associated with more than one connection. These IOP's 41, 69 and 70 communicate information particular to the disk unit 60 and the connections 64, 66 and 68. The IOP's 41, 69 and 70 may pass such information to a respective device driver 42, 71 72. Thus, each connection 64, 66 and 68 associates with its own device driver 42, 71 and 72, respectively. In this manner, the operating system 40 of FIG. 3 maintains an individual device driver 42, 71 and 72 for each connection 64, 66 and 68. This enables individual tracking of connection status and other characteristics, such as a connection's operability and connection information. Each device driver 42, 71 and 72 further includes identifying information particular to the disk unit 60. LHRI's 73, 74 and 75 are additionally created for each connection 64, 66 and 68, respectively. The LHRI's 73, 74 and 75 maintain consistent naming between the connections 64, 66 and 68 and the disk unit 60, as well as provide an interface mechanism for a user to address a particular connection. As discussed below in detail, for instance, an LHRI may be used to delete connection data from a disk unit. The information pertaining to the respective connection and the disk unit for each device driver 42, 71 and 72 may ultimately be communicated to a multipath driver 76. The multipath driver 76 may be created in response to the operating system 40 determining that more than one connections form a communication path between the host computer 12 and the disk unit 60. For instance, the primary device driver 42 may create the multipath driver 76 in response to a prompt from a new device driver 71. The new device driver 71 is associated with a new connection 66 to the same disk unit 60. In one sense, the multipath driver 76 comprises a logical interface layer between the upper level programming/storage manager 50 and logic associated with each connection. That is, the multipath driver 76 comprises a new layer between the device drivers 42, 69 and 70 that preserves the “one device” interface for current hardware and software implementations, while at the same time providing an interface that maintains information specific to the individual connections 64, 66 and 68 to the disk unit 60. The multipath driver 76 thus presents one “view” of a peripheral device/disk unit 60, no matter how many connections there are to the disk unit 60. This allows the upper level programming and storage manager 50 to accomplish functions such as read, write, reset, read-parameters, etc., while focusing only on the disk unit 60 that the multipath driver 76 provides. Because multiple connections are correlated to a single disk unit 60, they may be treated by the storage manager 50 as one entity. This ensures that connections to a disk unit are not excluded and that two connections for two different disk units are not mistakenly associated together. This mitigates the occurrence of data corruption. To this end, the multipath driver 76 may compile a complete connection list 77. The complete connection list may comprise information relating to each device driver 42, 71 and 72. For instance, the multipath driver 76 may compile the complete list 77 having pointers to the type/level/serial number field of each device driver associated with a given connection. Such information may be recorded in the complete list 77 whenever a connection becomes operable or a new disk unit is added, for instance. The complete connection list 77 is made available to the upper level programming/storage manager 50. The multipath driver 76 may also include an active connection list 78. The active list 78 may include pointers to the object fields of those device drivers that are available or otherwise desirable. For example, an exemplary active list may include pointers to device drivers 42 and 72, but not to device driver 71, whose associated cable connection 66 has been disconnected for maintenance, for example. Moreover, the more concise list reduces processing time and power needed to locate an appropriate connection. The multipath device 76 additionally handles connection failures by removing the failed connection 71 from the active list provided to the storage manager 50. The multipath device 76 additionally finds an alternative connection 64 and/or 68 to the disk unit 60 in response to the failed connection 66. At the same time, the multipath driver 76 can pass pertinent information, such that contained in the complete list 77, up to the storage manager 50. The storage manager 50 may send down read/write commands to the multipath driver 76. The multipath driver 76 in turn acts as an interface to coordinate and manage where the write/read commands should be routed in order to reach their target. That is, the multipath driver 76 may use the active connection list 78 to determine which connection(s) 64, 66 and/or 68 should be used. As discussed herein, the determination made by the multipath driver 76 may include load balancing and other considerations, besides whether a given connection is active. For exemplary purposes, FIG. 3 includes only one multipath driver 76, and accordingly, device drivers 42, 71 and 72 are associated with only one disk unit 60. One skilled in the art, however, will appreciate that the operating system 40 may include a number of additional multipath drivers as needed to manage connections of additional disk units. All communications for this particular disk unit 60 flow through one multipath driver 76 of FIG. 2. When there are multiple connections, each connection is associated with a device driver, a resource name and the same disk unit 60. The multipath driver 76 manages all of the objects. The storage manager 50 and other upper level programming remains unburdened by how many actual connections there are. Also, additional connections may be added “on the fly” without requiring any shutdown/quiesce, etc. Each disk unit 60, 62 of the peripheral device 18 includes a unique identifier string, such as an identifier string set by the storage server logical unit's manufacturer. The string can be read and is usually not changed by the system 10. The peripheral device 18 also includes a page having connection information. The connection information is used by the operating system 40 to keep track of disk units so that the same resource names are assigned to each disk unit and connection for each Initial Program Load (IPL). The disk unit 60 records the connection information pertaining to the connection 22 onto the page of the disk unit when the connection is initially coupled to the disk unit 60. As discussed in detail below, such information may be updated when a user removes a connection using the LHRI. A global device 79 of the operating system 40 of FIG. 3 may maintain a global list 80 of registration information. The registration information of the global list 80 may pertain to all connections registering on the computer 12. This registration information may differ from that included within the current connection list 77 of the multipath driver 76. Namely, the pointer information of the current list 77 pertains to just those connections associated with a single disk unit 60. The global list 80 may alternatively include pointers to all connections that have been registered in association with the computer 12. Registration information accessible to or otherwise included within the global list 80 includes type/level/serial number information that is communicated when a connection is activated or during an IPL, for instance. As discussed below, this global list 80 provides a mechanism to associate connections to the same disk unit with a primary disk unit for management considerations. The global list 80 may also be used to determine alternative routes that are useful when removing a connection. The discussion hereinafter will focus on the specific routines utilized to manage connections in a manner consistent with the present invention. The routines executed to implement the embodiments of the invention, whether implemented as part of an operating system or a specific application, component, program, object, module or sequence of instructions, will also be referred to herein as “computer programs,” “program code,” or simply “programs.” The computer programs typically comprise one or more instructions that are resident at various times in various memory and storage devices in a computer, and that, when read and executed by one or more processors in a computer, cause that computer to perform the steps necessary to execute steps or elements embodying the various aspects of the invention. Moreover, while the invention has and hereinafter will be described in the context of fully functioning computers and computer systems, those skilled in the art will appreciate that the various embodiments of the invention are capable of being distributed as a program product in a variety of forms, and that the invention applies equally regardless of the particular type of signal bearing media used to actually carry out the distribution. Examples of signal bearing media include but are not limited to recordable type media such as volatile and nonvolatile memory devices, floppy and other removable disks, hard disk drives, optical disks (e.g., CD-ROM's, DVD's, etc.), among others, and transmission type media such as digital and analog communication links. It will be appreciated that various programs described hereinafter may be identified based upon the application for which they are implemented in a specific embodiment of the invention. However, it should be appreciated that any particular program nomenclature that follows is used merely for convenience, and thus the invention should not be limited to use solely in any specific application identified and/or implied by such nomenclature. Moreover, those skilled in the art will recognize that the exemplary environments illustrated in FIGS. 1-3 are not intended to limit the present invention. Indeed, those skilled in the art will recognize that other alternative hardware and/or software environments may be used without departing from the scope of the invention. FIG. 4 shows a sequence of steps that are executable by the hardware and software environments of FIGS. 1-3. More particularly, the exemplary steps of the flowchart 90 of FIG. 4 are configured to determine, in part, a candidate for a primary connection. That is, the processes of the flowchart 90 are generally directed to locating a primary connection to a disk unit. All other connections to the same disk unit may then be associated with this primary connection for the purposes of organizing and managing appropriate connections according to their common disk unit. At block 92 of FIG. 4, a connection event occurs. A typical connection event may include a computer 12 powering up with connected disk units, a cable being plugged into a port or switch, and/or a new disk unit being configured. Type/level/serial number information pertinent to the connection undergoing the event at block 92 is reported at block 94 of FIG. 4. Such type/level/serial number information is commonly included within hardware devices by manufacturers for identification purposes. As such, the IOP 69 may retrieve the type/level/serial number information from the disk unit 60 via the physical connection 66. The IOP 69 may then initiate generation of a device driver 71 at block 96. The device driver 71 is thus generated in association with the IOP 69. That IOP 69 is in turn associated with the connection 66 and disk unit 60. The newly created device driver 71 may thus include access to the type/level/serial number retrieved at block 94. A pointer containing the address of the newly generated object is then added to the global list 80 at block 98. Where so configured, the global list 80 may include pointers to previously generated objects. These objects may or may not be associated with the same disk unit 60. At block 100, the device driver 71 causes a unique ID to be read off of a page of the disk unit 60 by the IOP 69. This unique ID may be stored at block 102 of the flowchart 90. Unlike the type/level/serial number information retrieved by the IOP 69 at block 94, the unique ID at block 100 is particular to a single disk unit 60. That is, no two disk units share the same unique ID. As such, these two types of identifying information thus provide different levels of granularity as to the specificity of identifying a given disk unit. As will be clear after a full reading of the specification, an embodiment consistent with the invention capitalizes on these differing levels of granularity to first locate a device driver in the global list 80 that has the same type/level/serial number as that read at block 94. As described in detail below in connection with FIG. 5, locating this first object assists in searching for a primary connection without unduly slowing other processes. To this end, the new device driver 71 searches the global list 80 at block 104 for type/level/serial number data that matches the data retrieved at block 94. As the type/level/serial number data is readily available, this portion of locating a primary connection is accomplished quickly with relatively few processing and memory requirements. The first identified device driver 42 having the type/level/serial number is locked at block 112 of FIG. 4. Of note, there has to be at least one such object having the matching type/level/serial number by virtue of the searching device driver 71, itself, which was added to the global list 80 at block 98. The lock of block 112 allows the located device driver 42 to continue to search the global list 80 while all other objects having the same type/level/serial number are effectively held, or kept inactive by the operating system 40. That is, the other device driver objects in the global list 80 that have the same type/level/serial number are not allowed to search until the lock is lifted off of the first located device driver 42. This precaution prevents subsequently registered objects in the global list 80 from simultaneously searching for a primary connection. Such simultaneous searching could erroneously result in determining more than one primary connection, which could lead to dissociation and data loss. In one embodiment, the lock's hold only applies to those device drivers on the global list 80 that have the sought after type/level/serial number. Because only those objects having the same type/level/serial number are held inactive, other methods on the list are able to search concurrently for other type/level/serial number objects associated with other disk units. This feature allows good efficiency by enabling parallel processing. While other objects having the same type/level/serial number remain inactive, the first located device driver 42 sequentially reads the unique identifiers of the locked objects at block 116. The device driver 42 having the lock then compares at block 117 the read unique identifier to the stored unique identifier recalled at block 114. That is, the locked device driver 42 may evaluate other device drivers on the list to find a matching unique ID. This unique ID is used to confirm that a particular device driver is with certainty associated with the same disk unit 60. The flowchart 118 of FIG. 5 shows a series of exemplary steps configured to associate the new device driver 71 with the primary located in FIG. 4. Turning more particularly to the processes of FIG. 5, the locked device driver 42 compares its own unique ID to the recalled ID of the newly created device driver 71 (which was stored at block 102 of FIG. 4). Where no unique ID associated with any device driver in the global list 80 matches the recalled ID at block 119 of FIG. 5, then a flag 67 is set in the locked 42 at block 120. This flag 67 designates the locked 42 as being a primary for a given disk unit 60. Consequently, all subsequent connections added to the global list 80 may locate and be associated with the primary. As discussed above, the first device driver 42 located in FIG. 4 may be the same device driver 71 that was generated at block 96 of FIG. 4. Such a circumstance occurs where the device driver generated at block 96 is the first to be added to the list. As discussed herein, such will be the case where that newly created object is to be designated as a primary device driver for a given disk unit. At block 122 of FIG. 5, the lock is released on the primary device driver 42. The primary 42 then may report itself for posting to the storage manager 50 or other upper level program at block 123. Where the unique identifier of the locked object 42 alternatively matches the recalled unique identifier of the newly created device driver 71 at block 119 of FIG. 5, then the new object 71 may be associated with the locked object, or primary device driver 42. More particularly, the new device driver 71 prompts the primary 42 to see if there is already a multipath driver 76 associated with the primary 42 (and disk unit 60). If not, the primary device driver 42 creates the multipath driver 76 at block 126 of FIG. 5. In any case, a pointer to the new, subordinate device driver 71 is added to the multipath driver 76 at block 128. In this manner, the multipath driver 76 develops arrays comprising the current and active connection lists 77 and 78, respectively. These lists in part correlate the new device driver 71 to the primary device driver 42, both of which are associated with the disk unit 60. The multipath driver 76 may update both the current connection list 77 and the active connection list 78 according to the status of the connections. The flowchart 130 of FIG. 6 shows one such exemplary sequence of steps suited to update the active connection list 78. More particularly, the steps of the flowchart 130 update and use the active connection list 78 to transparently transition to an alternative connection in the event a connection 66 becomes inoperable. For instance, the device driver 71 may communicate notice of a connection failure to the multipath driver 76 at block 132 of FIG. 6. In response to the failure, the multipath driver 76 determines which device driver 71 is associated with the failed connection 66 at block 134. For instance, the multipath driver 76 may read a pointer included the notice to the failed device driver. The multipath driver 76 may then remove the pointer to the connection from the active connection list 78 at block 136. This removal from the active connection list 78 ensures that the multipath driver 76 does not attempt to route data over the failed connection 66 again, or at least until the connection 66 is reestablished according to the connection processes of FIG. 4. Where the active list 78 at block 138 indicates that the multipath driver 76 has multiple, alternative connections to the disk unit 60 at its disposal, the multipath driver 76 may sequence down the list 78 to route data over a working connection 68. Of note, the transition to this new connection 68 is accomplished seamlessly, or without any discernable delay. Thus, computing operations remain uninterrupted in spite of the failed connection 66. To this end, the multipath driver 76 attempts routing data to the alternative connection 68 using a pointer to the appropriate device driver 72 associated with the connection 68. Where the communication succeeds at block 142, then operations seamlessly continue at block 144. Any subsequently discovered failed connection will be removed from the active list 78 at block 136 of FIG. 6. As such, a failed connection is only tried once, and the system 10 avoids unproductively cycling between failed connections. That is, each connection in the active list 78 is only tried once, and the maximum number of retries equals the number of connections in the list 78. Only where an alternative connection cannot be determined at block 138 of FIG. 6 will operations be suspended at block 146. These features of the list 78 and multipath driver 76 thus avoid having to check the status of each device driver when determining a new route. All objects included in the active list should be active as of the last update. These features also ensure an optimum number of retries and that all possible paths are tried. Minimizing memory requirements is also a benefit realized by the processes of the flowchart 150 shown in FIG. 7. More particularly, the exemplary steps of the flowchart 150 update connection information stored on a peripheral device/disk unit 60. In addition to reducing memory usage, the removal of connection information from the disk unit as discussed below facilitates processing of current connection information. Disk units include a limited space for storing connection information. Connection information includes an identifier sequence particular to the connection(s) that couple the disk unit to the computer. For instance, a readable and writeable page of data stored on the disk unit may include character strings associated with each connection coupled to the disk unit. As more connections are added, this storage space may fill up. Consequently, a feature of the present invention provides a mechanism for deleting erroneous or outdated connection information on each disk unit. Turning particularly to block 152 of FIG. 7, a user may input a command into the computer 12 to delete a failed, or non-reporting connection. In response, the operating system 40 of the computer 12 may automatically initiate processes to remove connection information from the disk unit 60. For instance, an LHRI 74 associated with the device driver 71 of the non-reporting connection 66 may prompt at block 154 the global driver 79 to locate a working connection that is coupled to the disk unit 60. That is, the LHRI 74 initiates processes to automatically find an alternative path, other than the non-reporting connection, to the same disk unit 60 that was formerly in active communication with the non-reporting connection. To this end, the global driver 79 at block 156 searches the global list 80 for type/level/serial number information associated with the disk unit 60. Should a match of the information be found, the global driver 79 prompts the device driver 72 associated with the applicable pointer in the list 80 to read connection data off of the disk unit 60 at block 164. A successful read of such data at block 166 may automatically initiate an evaluation of the connection data of the disk unit 60. Where the data cannot be read or the connection data does not match, the search for an alternative connection may continue at block 156. Alternatively, where a working connection to the disk unit 60 has been located and confirmed at block 168, then the device driver 72 may cause the connection data on the disk unit 60 to be removed using the IOP 70 at block 170. This connection data is then rewritten by the device driver 72 such that it contains no reference to the non-reporting connection. Once thus updated, the device driver 72 writes the updated connection information back to the disk unit 60 at block 174. A successful update at block 174 ends the updating sequence at block 160. In this manner, disk storage space may is preserved for accurate connection information and other uses. Moreover, the updated connection information may be used to verify connectivity upon IPL or installation, for instance. Under one such scenario, connection information from a disk unit may show a multipath driver that data pertaining to four different cables is resident within the disk unit storage. The multipath driver may use the active connection list 78 to verify that four connections are currently useable. A discrepancy may cause a check to be performed on objects associated with one or more of the connections to verify that they are still operating as reported. While the present invention has been illustrated by a description of various embodiments, and while these embodiments have been described in considerable detail, it is not the intention of the applicants to restrict, or in any way limit, the scope of the appended claims to such detail. For instance, any of the steps of the above exemplary flowcharts may be deleted, augmented, made to be simultaneous with another or be otherwise altered in accordance with the principles of the present invention. Furthermore, while computer systems consistent with the principles of the present invention may include virtually any number of networked computers, and while communication between those computers in the context of the present invention may be facilitated by an entitlement application, one skilled in the art will nonetheless appreciate that the processes of the present invention may also apply to direct communication between two computers as in the above example, or even to the internal processes of a single computer. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method, and illustrative example shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant's general inventive concept. | <SOH> BACKGROUND OF THE INVENTION <EOH>Effective computer operation requires the efficient reading and writing of data out to peripheral devices, such as storage disks. Fundamental to this read and write capability is the hardware connection that provides the physical pathway for communication with the peripheral device. Such a connection commonly comprises a fiber optic cable that couples to ports of both the computer and the peripheral device. As such, the cable comprises the communication link over which the read and write data is exchanged. For performance and reliability considerations, computer systems have been developed that use a number of cables to connect two devices. For example, a computer may write and read: data to and from a single disk storage unit using five or more cables. In one respect, using multiple cables to connect the same computer devices bolsters reliability. In the event that should one or more of the cables become disconnected or otherwise inoperable, another connection ideally remains available. A larger number of cables also provides increased bandwidth, allowing for more efficient data exchanges. Despite such processing and reliability advances, however, using redundant connections presents new challenges to computer performance. For example, existing systems are only configured to route data to a desired peripheral device using a single connection. The existing upper level programming of systems relies on the one-to-one relationship of a peripheral device to its respective cable connection in order to route data to the device. This is because the upper level programming sends a write/read command without regard to the connection. When writing data, for example, the upper level programs are configured only to “see” or otherwise process the address specific to the target disk unit. With the advent of redundant connections, a computer having a number of connections to the same disk unit must account for the existence of each cable connection in order to successfully read and write data. The status of each cable, for instance, whether a cable is reporting or not, deleted, added, etc., must be known. Otherwise, failure to separately track each connection can cause data to be written or read to or from an inappropriate device. Such miscommunication will result in file corruption. Furthermore, existing systems have relatively limited memory resources available to potentially store address, routing and other information pertaining to different communication paths. Accommodating multiple cable connections for each device must somehow not overburden available memory. Moreover, the time critical nature of computer processing requires that any routing scheme be sufficiently efficient to handle increasing workloads without delay. Therefore, a significant need exists for an improved manner of managing connections between hardware devices and a computer system. | <SOH> SUMMARY OF THE INVENTION <EOH>The invention addresses these and other problems associated with the prior art by providing an apparatus, program product and method of managing a number of physical connections to a peripheral device. An embodiment consistent with the invention includes a multipath driver that provides a logical connection interface. This interface allows a client to efficiently access the peripheral device over one or more of the physical connections. For instance, a client user or system may read and write data to the peripheral device without regard to which actual physical connection is used to route the data. Instead, that physical connection is automatically and transparently determined by the multipath driver. These and other advantages and features, which characterize the invention, are set forth in the claims annexed hereto and forming a further part hereof. However, for a better understanding of the invention, and of the advantages and objectives attained through its use, reference should be made to the Drawings, and to the accompanying descriptive matter, in which there is described exemplary embodiments of the invention. | 20040115 | 20070313 | 20050908 | 75115.0 | 0 | SHIN, CHRISTOPHER B | MULTIPLE CONNECTION MANAGEMENT SYSTEM | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,757,859 | ACCEPTED | Method and device for imaging with reorientation of an object | A medical imaging device and method having a display screen, a processor for processing image data in order to display the data in the form of a 3D model, and a user interface. The processor acquires at least two points positioned in the 3D model via the user interface; deduces the positioning of an axis defined by the two points in the 3D model, and reorients the 3D model in such a manner that the axis as indicated in this way is to be found in a predefined orientation relative to the plane of the display screen. | 1. An imaging device comprising means for display; means for processing image data in order to display the data in the form of a 3D model; a user interface; the means for processing acquires at least two points positioned in the 3D model via the user interface, to deduce the positioning of an axis defined by the two points in the 3D model, and to reorient the 3D model such that the axis is in a predefined orientation relative to a plane of the means for display. 2. The device according to claim 1 comprising: means for positioning an image acquisition system relative to an object, which means implement positioning of the acquisition system to correspond with an orientation of the model as displayed on the means for display. 3. The device according to claim 2 comprising: an image acquisition system; and means for orienting by controlling an angular position of the system to correspond with an orientation of the 3D model as defined on means for display. 4. The device according to claim 1 wherein the means for processing orients the 3D model in such a manner that the axis defined by the two points indicated by the user is parallel to the plane of the means for display. 5. The device according to claim 2 wherein the means for processing orients the 3D model in such a manner that the axis defined by the two points indicated by the user is parallel to the plane of the means for display. 6. The device according to claim 3 wherein the means for processing orients the 3D model in such a manner that the axis defined by the two points indicated by the user is parallel to the plane of the means for display. 7. The device according to claim 1 wherein the means for processing implements rotation of the 3D model about the axis defined by the two points indicated by the user. 8. The device according to claim 2 wherein the means for processing implements rotation of the 3D model about the axis defined by the two points indicated by the user. 9. The device according to claim 3 wherein the means for processing implements rotation of the 3D model about the axis defined by the two points indicated by the user. 10. The device according to claim 4 wherein the means for processing implements rotation of the 3D model about the axis defined by the two points indicated by the user. 11. The device according to claim 1 wherein the means for processing causes display of a section view of the 3D model on a section plane which presents a predefined orientation relative to the axis indicated by the user. 12. The device according to claim 2 wherein the means for processing causes display of a section view of the 3D model on a section plane which presents a predefined orientation relative to the axis indicated by the user. 13. The device according to claim 3 wherein the means for processing causes display of a section view of the 3D model on a section plane which presents a predefined orientation relative to the axis indicated by the user. 14. The device according to claim 4 wherein the means for processing causes display of a section view of the 3D model on a section plane which presents a predefined orientation relative to the axis indicated by the user. 15. The device according to claim 7 wherein the means for processing causes display of a section view of the 3D model on a section plane which presents a predefined orientation relative to the axis indicated by the user. 16. The device according to claim 11 wherein the means for processing moves the section plane progressively under control from the user interface. 17. The device according to claim 12 wherein the means for processing moves the section plane progressively under control from the user interface. 18. The device according to claim 13 wherein the means for processing moves the section plane progressively under control from the user interface. 19. The device according to claim 14 wherein the means for processing moves the section plane progressively under control from the user interface. 20. The device according to claim 15 wherein the means for processing moves the section plane progressively under control from the user interface. 21. The device according to claim 11 wherein the means for processing moves the section plane in the 3D model while keeping the section plane in a predefined orientation. 22. The device according to claim 16 wherein the means for processing moves the section plane in the 3D model while keeping the section plane in a predefined orientation. 23. The device according to claim 11 wherein the predefined orientation of the section plane is orientated parallel to the axis indicated by the user. 24. The device according to claim 16 wherein the means for processing moves the section plane in the 3D model while keeping the section plane in a predefined orientation. 25. The device according to claim 21 wherein the means for processing moves the section plane in the 3D model while keeping the section plane in a predefined orientation. 26. The device according to claim 1 wherein the means for processing acquires at least three points positioned in the 3D model by means of the user interface, to deduce two axes therefrom each passing through a pair of the points, and to reorient the 3D model in such a manner that the two axes are substantially parallel to the means for display. 27. The device according to claim 2 wherein the means for processing acquires at least three points positioned in the 3D model by means of the user interface, to deduce two axes therefrom each passing through a pair of the points, and to reorient the 3D model in such a manner that the two axes are substantially parallel to the means for display. 28. The device according to claim 3 wherein the means for processing acquires at least three points positioned in the 3D model by means of the user interface, to deduce two axes therefrom each passing through a pair of the points, and to reorient the 3D model in such a manner that the two axes are substantially parallel to the means for display. 29. The device according to claim 4 wherein the means for processing acquires at least three points positioned in the 3D model by means of the user interface, to deduce two axes therefrom each passing through a pair of the points, and to reorient the 3D model in such a manner that the two axes are substantially parallel to the means for display. 30. The device according to claim 7 wherein the means for processing acquires at least three points positioned in the 3D model by means of the user interface, to deduce two axes therefrom each passing through a pair of the points, and to reorient the 3D model in such a manner that the two axes are substantially parallel to the means for display. 31. The device according to claim 11 wherein the means for processing acquires at least three points positioned in the 3D model by means of the user interface, to deduce two axes therefrom each passing through a pair of the points, and to reorient the 3D model in such a manner that the two axes are substantially parallel to the means for display. 32. The device according to claim 16 wherein the means for processing acquires at least three points positioned in the 3D model by means of the user interface, to deduce two axes therefrom each passing through a pair of the points, and to reorient the 3D model in such a manner that the two axes are substantially parallel to the means for display. 33. The device according to claim 21 wherein the means for processing acquires at least three points positioned in the 3D model by means of the user interface, to deduce two axes therefrom each passing through a pair of the points, and to reorient the 3D model in such a manner that the two axes are substantially parallel to the means for display. 34. The device according to claim 23 wherein the means for processing acquires at least three points positioned in the 3D model by means of the user interface, to deduce two axes therefrom each passing through a pair of the points, and to reorient the 3D model in such a manner that the two axes are substantially parallel to the means for display. 35. The device according to claim 1 wherein the means for processing acquires a plurality of points, to deduce a plurality of axes therefrom that are not all mutually parallel, each passing through a different pair of points selected from the plurality of points, and to reorient the 3D model bringing the set of the axes as close as possible to parallel with the plane of the means for display. 36. The device according to claim 2 wherein the means for processing acquires a plurality of points, to deduce a plurality of axes therefrom that are not all mutually parallel, each passing through a different pair of points selected from the plurality of points, and to reorient the 3D model bringing the set of the axes as close as possible to parallel with the plane of the means for display. 37. The device according to claim 3 wherein the means for processing acquires a plurality of points, to deduce a plurality of axes therefrom that are not all mutually parallel, each passing through a different pair of points selected from the plurality of points, and to reorient the 3D model bringing the set of the axes as close as possible to parallel with the plane of the means for display. 38. The device according to claim 4 wherein the means for processing acquires a plurality of points, to deduce a plurality of axes therefrom that are not all mutually parallel, each passing through a different pair of points selected from the plurality of points, and to reorient the 3D model bringing the set of the axes as close as possible to parallel with the plane of the means for display. 39. The device according to claim 7 wherein the means for processing acquires a plurality of points, to deduce a plurality of axes therefrom that are not all mutually parallel, each passing through a different pair of points selected from the plurality of points, and to reorient the 3D model bringing the set of the axes as close as possible to parallel with the plane of the means for display. 40. The device according to claim 11 wherein the means for processing acquires a plurality of points, to deduce a plurality of axes therefrom that are not all mutually parallel, each passing through a different pair of points selected from the plurality of points, and to reorient the 3D model bringing the set of the axes as close as possible to parallel with the plane of the means for display. 41. The device according to claim 16 wherein the means for processing acquires a plurality of points, to deduce a plurality of axes therefrom that are not all mutually parallel, each passing through a different pair of points selected from the plurality of points, and to reorient the 3D model bringing the set of the axes as close as possible to parallel with the plane of the means for display. 42. The device according to claim 21 wherein the means for processing acquires a plurality of points, to deduce a plurality of axes therefrom that are not all mutually parallel, each passing through a different pair of points selected from the plurality of points, and to reorient the 3D model bringing the set of the axes as close as possible to parallel with the plane of the means for display. 43. The device according to claim 23 wherein the means for processing acquires a plurality of points, to deduce a plurality of axes therefrom that are not all mutually parallel, each passing through a different pair of points selected from the plurality of points, and to reorient the 3D model bringing the set of the axes as close as possible to parallel with the plane of the means for display. 44. The device according to claim 26 wherein the means for processing acquires a plurality of points, to deduce a plurality of axes therefrom that are not all mutually parallel, each passing through a different pair of points selected from the plurality of points, and to reorient the 3D model bringing the set of the axes as close as possible to parallel with the plane of the means for display. 45. The device according to claim 1 comprising: means for identifying a final orientation of the 3D model as confirmed by the user; and means for producing a command signal for physically orienting an image sensor relative to the user in correspondence with the final confirmed orientation. 46. The device according to claim 2 comprising: means for identifying a final orientation of the 3D model as confirmed by the user; and means for producing a command signal for physically orienting an image sensor relative to the user in correspondence with the final confirmed orientation. 47. The device according to claim 3 comprising: means for identifying a final orientation of the 3D model as confirmed by the user; and means for producing a command signal for physically orienting an image sensor relative to the user in correspondence with the final confirmed orientation. 48. The device according to claim 4 comprising: means for identifying a final orientation of the 3D model as confirmed by the user; and means for producing a command signal for physically orienting an image sensor relative to the user in correspondence with the final confirmed orientation. 49. The device according to claim 7 comprising: means for identifying a final orientation of the 3D model as confirmed by the user; and means for producing a command signal for physically orienting an image sensor relative to the user in correspondence with the final confirmed orientation. 50. The device according to claim 11 comprising: means for identifying a final orientation of the 3D model as confirmed by the user; and means for producing a command signal for physically orienting an image sensor relative to the user in correspondence with the final confirmed orientation. 51. The device according to claim 16 comprising: means for identifying a final orientation of the 3D model as confirmed by the user; and means for producing a command signal for physically orienting an image sensor relative to the user in correspondence with the final confirmed orientation. 52. The device according to claim 21 comprising: means for identifying a final orientation of the 3D model as confirmed by the user; and means for producing a command signal for physically orienting an image sensor relative to the user in correspondence with the final confirmed orientation. 53. The device according to claim 23 comprising: means for identifying a final orientation of the 3D model as confirmed by the user; and means for producing a command signal for physically orienting an image sensor relative to the user in correspondence with the final confirmed orientation. 54. The device according to claim 26 comprising: means for identifying a final orientation of the 3D model as confirmed by the user; and means for producing a command signal for physically orienting an image sensor relative to the user in correspondence with the final confirmed orientation. 55. The device according to claim 35 comprising: means for identifying a final orientation of the 3D model as confirmed by the user; and means for producing a command signal for physically orienting an image sensor relative to the user in correspondence with the final confirmed orientation. 56. A method for displaying a 3D model in imaging comprising: providing means for display; providing means for processing in order to display data in the form of a 3D model; and providing a user interface fitted to the means for processing; positioning at least two points in the 3D model by means of the user interface; causing the means for processing to deduce therefrom the position of an axis defined by the points on the 3D model; and causing the means for processing to reorient the 3D model such that the axis lies in a predefined orientation relative to a plane of the means for display. 57. A computer program comprising code means that when executed on a computer carry out the steps of the means for processing of claim 56. 58. A computer program on a carrier carrying code that when executed on a computer carry out the steps of the means for processing of claim 56. | CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of a priority under 35 USC 119(a)-(d) to French Patent Application No. 03 01046 filed Jan. 30, 2003, the entire contents of which are hereby incorporated by reference. BACKGROUND OF THE INVENTION An embodiment of the invention relates to displaying three-dimensional (3D) images of an object that may be acquired in radiology, and in particular to representing anatomical sites in preparation for, or even during, a therapeutic act performed by interventional radiology or by surgery. More particularly, an embodiment of the invention relates to tools enabling an optimum orientation to be identified for a biological object represented in three dimensions or enabling an optimum selection to be made for presenting a section of such an object on a display, such as a screen. In the field of interventional radiology, therapeutic tools are presently deployed and moved under fluoroscopic guidance. To do this, it is desired visually to find an appropriate working view by orienting the imaging system, where such orientation provides a suitable display of the pathology to be treated. With complex pathologies such as cerebral aneurysms, it is difficult for a radiologist or other practitioner to find such a suitable working view. Prior to the introduction of three-dimensional tools in angiography theaters, it was typically the practice to take a series of recordings or acquisitions under different angles selected empirically until a satisfactory view was obtained. That approach had several drawbacks, and in particular the high dose of radiation, such as X-rays, administered to the patient and also the high dose of injected contrast media. Furthermore, the time devoted to that procedure could be lengthy. With the introduction of tools with three-dimensional representation, the preferred technique for selecting the working view has been transformed considerably. In a first step, 3D acquisition is performed, and then the radiologist examines the image displayed on a computer screen in three dimensions while interactively applying rotations to the 3D model until an acceptable view is found. In a second step, the user transmits the selected angle of observation to a radiological acquisition system as a control parameter for automatically moving the gantry until the desired working view is obtained. Interactive rotation of the image in three dimensions has the advantage of not requiring repeated doses of X-rays and of not requiring repeated doses of contrast medium. Nevertheless, the quality of the result depends essentially on the skill of the user in interactively rotating the three-dimensional image. In addition, that technique does not save a significant amount of time compared with the earlier techniques. Furthermore, that technique does not ensure that the selected working view is the optimum view, given that the selection is based essentially on the skill of the user in manipulating a 3D image. In other words, there might be some other direction of observation that is better than that found by the user, but which the user did not find. BRIEF DESCRIPTION OF THE INVENTION An embodiment of the invention provides a three-dimensional radiological display system enabling a working view to be positioned easily, regardless of whether the view is three-dimensional or in section. In an embodiment of the invention, an imaging device comprises: means for display; means for processing image data in order to display the data in the form of a 3D model, and a user interface; the means for processing acquires at least two points positioned in the 3D model via the user interface, to deduce the positioning of an axis defined by the two points in the 3D model, and to reorient the 3D model such that the axis is in a predefined orientation relative to a plane of the means for display. An embodiment of the invention also provides a method of displaying a 3D model imaging, the method comprising: providing means for display; providing means for processing image data in order to display the data in the form of a 3D model; providing a user interface fitted to the means for processing; positioning at least two points in the 3D model by means of the user interface; causing the means for processing to deduce therefrom a position of an axis defined by the points on the 3D model; and causing the means for processing to reorient the 3D model such that the axis lies in a predefined orientation relative to a plane of the means for display. BRIEF DESCRIPTION OF THE DRAWINGS The invention and embodiments thereof will be better understood when read with the following detailed description made with reference to the accompanying figures, in which: FIG. 1 shows a system once a user has placed two points on a 3D model; FIG. 2 shows a system after reorientation on the basis of the points positioned by the user; FIG. 3 shows a system for displaying an aneurysm using three points that define two axes; FIG. 4 shows a system for displaying a V-shaped bifurcation using three points defining two axes; and FIG. 5 shows a system for displaying a Y-shaped bifurcation using four points defining three axes. DETAILED DESCRIPTION OF THE INVENTION An embodiment is described with reference to FIGS. 1 and 2. In this embodiment, a user seeks to find the best working view on a three-dimensional model of a cerebral aneurysm, which model is obtained by previously performing image acquisition on the patient; this acquisition can be implemented, for example, by means of magnetic resonance imagery (MRI), a scanner, or an angiography theater. In this embodiment, the system comprises means for display, such as screen 2; means for processing, such as image-processing processor 4; and means for providing a control interface, i.e., interactive manual interface, in this case a computer mouse 6. In this embodiment, the system proposes a display of an anatomical zone in the form of a 3D model. For example, the anatomical zone may be a blood vessel carrying an aneurysm in some arbitrary orientation. The aneurysm appears to be a slight bulge on the margin of the vessel carrying it. The user is then invited to position an axis 100 modeling the main positioning of the carrying vessel. To do this, the user places two points on the carrying vessel at two distinct locations, preferably on opposite sides of the aneurysm. These two points 10 and 20 are placed, for example, by using two cross-section views of the carrying vessel, the views being located on either side of the aneurysm. The two points in this embodiment or the points in further embodiments can also be positioned in some other way, for example on 3D images obtained using surface rendering techniques, volume rendering techniques, or maximum intensity projection (MIP). From the two points, the means for processing 4, i.e., the image processing processor, identifies an axis 100 within the three-dimensional model in its initial display on the screen. After this axis 100 has been positioned, the processor reprocesses the displayed image so that the three-dimensional model is subjected to a rotation, which rotation causes the axis as previously defined manually to be brought into alignment parallel with the plane of the display screen. This first rotation can be automatic and is typically the shortest rotation that serves to bring the axis into alignment with the screen, being close to a direct projection of the axis onto the screen. The processor is then configured to implement image processing under manual control of the user, using the previously-defined axis as a reference. In the present example, the user moves the mouse 6 progressively so as to cause the three-dimensional model to move progressively about the previously defined axis 100. The carrying vessel and its aneurysm are thus seen to pivot progressively about the axis of the carrying vessel while the user continues to examine it visually. The user can thus easily identify the ideal position in pivoting, and after making several turns in opposite directions about the optimum position, the user freezes the mouse in the optimum position. The user then has the best view of the aneurysm. This best view is, for example, the view that enables the portion 50 of the aneurysm (referred to as its “collar”) to be seen most clearly, which portion is shown in FIG. 2. The resulting image can then be considered as being optimal by the user and can be taken into account by the system as the working view to be adopted. The processor identifies the current parameters defining the orientation of the three-dimensional model as the display parameters to be adopted either merely for subsequent display or else during a forthcoming medical intervention. In this and other embodiments, the identification of the optimum orientation is followed by a command for repositioning a radiation detector relative to the body of the patient. Thus, the optimum orientation selected on the screen subsequently defines the image rotation to be retranscribed by the processor in the form of a physical orientation to be given to the detector. Once this physical reorientation has been adopted by the detector (the sensor then lying parallel with the carrying vessel), the detector supplies an image that corresponds precisely to the orientation selected by the user, this image being without reprocessing. An embodiment of the invention makes it possible not only to position a 3D model on a computer screen, but also to orient the arch in a vascular theater with the corresponding angle. It thus comprises a device which serves not only to reorient a model on a screen, but which is capable also, at the request of the user, of controlling the mechanical movement of an image acquisition system so that the system takes up the determined angle. Intervention can then be performed on the aneurysm with the anatomical region of the intervention being displayed continuously with the best viewing angle. In this embodiment, the system also makes it possible to select an optimum section view of the pathology under observation. Thus, once the reference axis has been positioned by the user and the 3D model has been reoriented so that the axis is parallel to the screen, the image processor proposes a section position to the user under progressive displacement of the mouse 6. With the mouse, the user then moves a section plane parallel to the surface of the screen in depth, i.e., in depth in the object displayed. Several other embodiments are possible, for example, by moving the section plane in translation parallel to the reference axis, or perpendicularly to the reference axis while still keeping it perpendicular to the screen. The embodiment, as described above, is typically applied to displaying an aneurysm. Nevertheless, and in particular because this embodiment implements rotation about an axis defining a vessel, another application is observing a stenosis (a narrowing of a vessel). In that case also, by turning about a selected axis, it possible to find the view that reveals the depth of the narrowing as well as possible. The manually-placed axis, in the case of a vessel, could also be positioned on a needle that appears on the screen since it has been placed in the surgical zone under observation. In addition to the above-described embodiment in which the user specifies only one reference axis manually, it is also possible for a plurality of axes to be defined manually. An example comprises positioning three points on the three-dimensional model so as to define between them two axes, the two axes defining a plane of observation. This plane is taken into account by the image processing processor in order to begin by reorienting the 3D model in such a manner that the plane lies parallel to the screen. The two axes as defined in this way are then both parallel to the screen. It is also appropriate to use two reference axes for an aneurysm, thus enabling it to be reoriented (FIG. 3) on the basis not only of the two points 10 and 20 representing the carrying vessel, but also on the basis of an additional point 30 positioned on the aneurysm itself. In this particular case, the two axes enabling the 3D model to be repositioned automatically are thus the axis of the carrying vessel 100 and, for example, an axis 110 perpendicular to the axis of the vessel and passing through the additional point 30 situated on the aneurysm. Another embodiment comprises reorienting a V-shaped bifurcation of two vessels (FIG. 4). Two axes 100 and 200 are then positioned using three points 10, 20, and 30 in order to represent each of the two bifurcations, the three-dimensional model being reoriented in such a manner that the two axes 100 and 200 are simultaneously parallel to the screen. A view of this bifurcation is then obtained in which the V-shape is at maximum spread. In this case also, the system is designed to propose displacement of successive sections in depth and parallel to the screen under manual control of the user. The two 3D axes 100 and 200 are kept parallel to the screen while displacing sections in this way. In another embodiment as shown in FIG. 5, which is particularly adapted to displaying a Y-shaped bifurcation of vessels, the user defines three distinct axes 100, 200, and 300 by manually positioning four points 10, 20, 30, and 40. By placing three 3D axes on respective ones of the three branches of the Y-shaped bifurcation, the user provides the image processing processor with geometrical references representative of the positioning of each of the branches. The processor then optimizes the positioning of the display that is such that each of the three axes is as close as possible to being parallel with the surface of the screen. The positioning of three axes can also be defined by some greater number of points, for example six points organized in three pairs, each defining one axis. In this case also, the user can displace a section plane progressively in depth parallel to the initial display, with the orientation of each of the three axes relative to the plane of the screen remaining constant. The three-axis embodiment is also suitable for observing an aneurysm. The aneurysm may be considered as being ellipsoidal, and can be represented by its two main axes (longitudinal axis and transverse axis). The two axes are thus modeled manually by manually positioning two pairs of points. The third axis comprises, for example, the axis of the carrying vessel. The processor then reorients the 3D model so as to bring the three axes as close as possible to being parallel with the screen. In this embodiment as in the preceding embodiments, provision is preferably made for the optimum view as established in this way to be transmitted in the form of a command for positioning the image sensor physically relative to the patient using motor-driven means. One skilled in the art may propose or make various modifications to the structure/way and/or function and/or result and/or steps of the disclosed embodiments and equivalents thereof without departing from the scope and extant of the invention. | <SOH> BACKGROUND OF THE INVENTION <EOH>An embodiment of the invention relates to displaying three-dimensional (3D) images of an object that may be acquired in radiology, and in particular to representing anatomical sites in preparation for, or even during, a therapeutic act performed by interventional radiology or by surgery. More particularly, an embodiment of the invention relates to tools enabling an optimum orientation to be identified for a biological object represented in three dimensions or enabling an optimum selection to be made for presenting a section of such an object on a display, such as a screen. In the field of interventional radiology, therapeutic tools are presently deployed and moved under fluoroscopic guidance. To do this, it is desired visually to find an appropriate working view by orienting the imaging system, where such orientation provides a suitable display of the pathology to be treated. With complex pathologies such as cerebral aneurysms, it is difficult for a radiologist or other practitioner to find such a suitable working view. Prior to the introduction of three-dimensional tools in angiography theaters, it was typically the practice to take a series of recordings or acquisitions under different angles selected empirically until a satisfactory view was obtained. That approach had several drawbacks, and in particular the high dose of radiation, such as X-rays, administered to the patient and also the high dose of injected contrast media. Furthermore, the time devoted to that procedure could be lengthy. With the introduction of tools with three-dimensional representation, the preferred technique for selecting the working view has been transformed considerably. In a first step, 3D acquisition is performed, and then the radiologist examines the image displayed on a computer screen in three dimensions while interactively applying rotations to the 3D model until an acceptable view is found. In a second step, the user transmits the selected angle of observation to a radiological acquisition system as a control parameter for automatically moving the gantry until the desired working view is obtained. Interactive rotation of the image in three dimensions has the advantage of not requiring repeated doses of X-rays and of not requiring repeated doses of contrast medium. Nevertheless, the quality of the result depends essentially on the skill of the user in interactively rotating the three-dimensional image. In addition, that technique does not save a significant amount of time compared with the earlier techniques. Furthermore, that technique does not ensure that the selected working view is the optimum view, given that the selection is based essentially on the skill of the user in manipulating a 3D image. In other words, there might be some other direction of observation that is better than that found by the user, but which the user did not find. | <SOH> BRIEF DESCRIPTION OF THE INVENTION <EOH>An embodiment of the invention provides a three-dimensional radiological display system enabling a working view to be positioned easily, regardless of whether the view is three-dimensional or in section. In an embodiment of the invention, an imaging device comprises: means for display; means for processing image data in order to display the data in the form of a 3D model, and a user interface; the means for processing acquires at least two points positioned in the 3D model via the user interface, to deduce the positioning of an axis defined by the two points in the 3D model, and to reorient the 3D model such that the axis is in a predefined orientation relative to a plane of the means for display. An embodiment of the invention also provides a method of displaying a 3D model imaging, the method comprising: providing means for display; providing means for processing image data in order to display the data in the form of a 3D model; providing a user interface fitted to the means for processing; positioning at least two points in the 3D model by means of the user interface; causing the means for processing to deduce therefrom a position of an axis defined by the points on the 3D model; and causing the means for processing to reorient the 3D model such that the axis lies in a predefined orientation relative to a plane of the means for display. | 20040115 | 20070130 | 20050127 | 70585.0 | 0 | SAMS, MICHELLE L | METHOD AND DEVICE FOR IMAGING WITH REORIENTATION OF AN OBJECT | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,757,931 | ACCEPTED | RF transmitter having improved out of band attenuation | A radio frequency transmitter includes a digital baseband and coding module, an inverse fast Fourier transform (IFFT) module, a complex digital filter, a complex digital-to-analog converter and a radio frequency modulation module. The digital baseband and coding module is operably coupled to convert outbound data into outbound symbols in accordance with a baseband encoding protocol. The IFFT module is operably coupled to convert the outbound symbols into a complex time domain sample sequence. The complex digital filter is operably coupled to filter the complex time domain sequence such that signal strength of outbound RF signals in an exclusion RF band is at or below a specified signal strength with negligible attenuation on in-band signal strength. | 1. A radio frequency transmitter comprises: digital baseband encoding module operably coupled to convert outbound data into outbound symbols in accordance with a baseband encoding protocol; inverse discrete Fourier transform (IDFT) module operably coupled to convert the outbound symbols into a complex time domain sample sequence; complex digital filter operably coupled to filter the complex time domain sample sequence to produce a filtered complex time domain sample sequence; complex digital to analog converter operably coupled to convert the filtered complex time domain sample sequence into in-phase analog signal components and quadrature analog signal components; and radio frequency modulation module operably coupled to convert the in-phase and quadrature analog signal components into outbound radio frequency signals, wherein the complex digital filter attenuates the complex time domain sample sequence such that signal strength of the outbound radio frequency signals in an exclusion radio frequency band is at or below a specified signal strength. 2. The radio frequency transmitter of claim 1, wherein the complex digital filter comprises at least one of: a low pass filter; and a bandpass filter. 3. The radio frequency transmitter of claim 2, wherein the low pass filter comprises at least one of: a multiple order elliptic low pass filter; and a multiple order Chebychev low pass filter. 4. The radio frequency transmitter of claim 2, wherein the low pass filter comprises: a first 2nd order bi-quad stage; a second 2nd order bi-quad stage; a third 2nd order bi-quad stage operably coupled in a cascade manner to the first and second 2nd order bi-quad stages, wherein the cascaded first, second, and third 2nd order bi-quad stages filter the complex time domain sample sequence to produce a multiple order filtered sample sequence; and a gain module operably coupled to amplify the multiple order filtered sample sequence to produce the filtered complex time domain sample sequence. 5. The radio frequency transmitter of claim 1, wherein the baseband encoding protocol comprises at least one of: IEEE 802.11g, IEEE 802.11a; and IEEE 802.11b. 6. The radio frequency transmitter of claim 1, wherein the IDFT module comprises: an inverse fast Fourier transform (IFFT) module. 7. A radio frequency transmitter comprises: digital baseband encoding module operably coupled to convert outbound data into outbound symbols in accordance with a baseband encoding protocol; digital filter operably coupled to filter the outbound symbols to produce a filtered outbound symbols; inverse discrete Fourier transform (IDFT) module operably coupled to convert the filtered outbound symbols into a complex time domain sample sequence; complex digital to analog converter operably coupled to convert the complex time domain sample sequence into in-phase analog signal components and quadrature analog signal components; and radio frequency modulation module operably coupled to convert the in-phase and quadrature analog signal components into outbound radio frequency signals, wherein the complex digital filter attenuates the complex time domain sample sequence such that signal strength of the outbound radio frequency signals in an exclusion radio frequency band is at or below a specified signal strength. 8. The radio frequency transmitter of claim 7, wherein the digital filter comprises at least one of: a low pass filter; and a bandpass filter. 9. The radio frequency transmitter of claim 8, wherein the low pass filter comprises at least one of: a multiple order elliptic low pass filter; and a multiple order Chebychev low pass filter. 10. The radio frequency transmitter of claim 8, wherein the low pass filter comprises: a first 2nd order bi-quad stage; a second 2nd order bi-quad stage; a third 2nd order bi-quad stage operably coupled in a cascade manner to the first and second 2nd order bi-quad stages, wherein the cascaded first, second, and third 2nd order bi-quad stages filter the complex time domain sample sequence to produce a multiple order filtered sample sequence; and a gain module operably coupled to amplify the multiple order filtered sample sequence to produce the filtered complex time domain sample sequence. 11. The radio frequency transmitter of claim 7, wherein the baseband encoding protocol comprises at least one of: IEEE 802.11g, IEEE 802.11a; and IEEE 802.11b. 12. The radio frequency transmitter of claim 7, wherein the IDFT module comprises: an inverse fast Fourier transform (IFFT) module. | BACKGROUND OF THE INVENTION 1. Technical Field of the Invention This invention relates generally to wireless communication systems and, more particularly, to radio frequency transmitters used within such systems. 2. Description of the Related Art As is known, use of frequencies for wireless communications is partitioned into frequency bands by government agencies. For instance, the Federal Communications Commission (FCC) defines, for the United States, frequency bands for specific uses and for which an FCC license is required (e.g., radio transmissions, television transmissions, etc.) and also defines frequency bands that are unlicensed and, as such, can be used for a variety of applications. For instance, the FCC has defined several frequency bands in the radio frequency spectrum as being unlicensed. Such unlicensed frequency bands include 902-928 MHz, 2.4-2.483 GHz and 5.75-5.85 GHz, which are collectively referred to as the ISM (Industrial Scientific Medical) band. Currently, the ISM band is used for in-building and system applications (e.g., bar code readers), industrial microwave ovens, wireless patient monitors, and wireless local area networks (WLAN). As is also known, there are standard bodies that define standards for WLAN equipment within the ISM band. Such standards include, but are not limited to, Bluetooth, IEEE 802.11(a), IEEE 802.11(b), and IEEE 802.11(g). The IEEE 802.11(g) standard provides wireless LAN operation specifications in the 2.4-2.482 GHz band. Specification applies to both transmitters and receivers and defines data rates, modulation schemes, transmitter architectures, receiver architectures, etc. In general, the specified modulation schemes are based on Orthogonal Frequency Division Multiplexing (OFDM) which, for 802.11(g) divides the 2.4-2.482 GHz band into a plurality of channels. Further, as specified, the channels at the boundaries of the frequency band (e.g., channels 1 and 11 that are centered at 2.412 GHz and 2.462 GHz, respectively) are preferred channels of use. As is further known, the FCC has defined exclusion frequency bands around the 2.4-2.482 GHz frequency band. One exclusion frequency band begins at 2.390 GHz and includes lower frequencies and the other exclusion frequency band begins at 2.4835 GHz and includes higher frequencies. An issue arises when fabricating a transmitter in accordance with the architecture defined within the 802.11(g) specification, in that, for channels 1 and 11, the transmit power levels in the exclusion frequency bands are too great, which violates the FCC restrictions on use of the exclusion frequency bands. Therefore, a need exists for a transmitter that provides desired power levels within prescribed frequency bands of operation and does not violate transmit power levels in non-prescribed frequency bands. BRIEF SUMMARY OF THE INVENTION The RF transmitter having out-of-band attenuation of the present invention substantially meets these needs and others. In one embodiment, a radio frequency transmitter includes a digital baseband and coding module, an inverse fast Fourier transform (IFFT) module, a complex digital filter, a complex digital-to-analog converter and a radio frequency modulation module. The digital baseband and coding module is operably coupled to convert outbound data into outbound symbols in accordance with a baseband encoding protocol (e.g., binary phase shift keying (BPSK), orthogonal frequency division multiplexing (OFDM), quadrature phase shift keying (QPSK), 16 quadrature amplitude modulation (QAM) OFDM, and/or 64 QAM OFDM). The inverse fast Fourier transform module is operably coupled to convert the outbound symbols into a complex time domain sample sequence. The complex digital filter is operably coupled to filter the complex time domain sequence to produce a filtered complex time domain sample sequence. The complex digital-to-analog converter is operably coupled to convert the filtered complex time domain sample sequence into in-phase analog signal components and quadrature analog signal components. The radio frequency modulation module is operably coupled to convert the in-phase and quadrature analog signal components into outbound radio frequency signals. As configured, the complex digital filter attenuates the complex time domain sample sequence such that signal strength of the outbound radio frequency signals in an exclusion radio frequency band is at or below a specified signal strength with negligible attenuation on in-band signal strength. In another embodiment, a radio frequency transmitter includes a digital baseband encoding module, a digital filter, an inverse fast Fourier transform module, a complex digital-to-analog converter, and a radio frequency modulation module. The digital baseband and coding module is operably coupled to convert outbound data into outbound symbols in accordance with a baseband encoding protocol. The digital filter is operably coupled to filter the outbound symbols to produce filtered outbound symbols. The inverse fast Fourier transform module is operably coupled to convert the filtered outbound symbols into a complex time domain sample sequence. The complex digital-to-analog converter is operably coupled to convert the complex time domain sample sequence into in-phase analog signal components and quadrature analog signal components. The radio frequency modulation module is operably coupled to convert the in-phase and quadrature analog signal components into outbound radio frequency signals. The complex digital filter is operably to attenuate the complex time domain sample sequence such that signal strength of the outbound radio frequency signals in an exclusion radio frequency band is at or below a specified signal strength while having negligible attenuation on the signal strength within a desired frequency band. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS FIG. 1 is a schematic block diagram of a wireless communication system in accordance with the present invention; FIG. 2 is a schematic block diagram of a wireless communication device in accordance with the present invention; FIG. 3 is a schematic block diagram of a transmitter in accordance with the present invention; FIG. 4 is a schematic block diagram of a complex digital filter in accordance with the present invention; FIG. 5 is a schematic block diagram of a bi-quad stage of the complex digital filter in accordance with the present invention; and FIG. 6 is a schematic block diagram of an alternate transmitter in accordance with the present invention. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 is a schematic block diagram illustrating a communication system 10 that includes a plurality of base stations and/or access points 12-16, a plurality of wireless communication devices 18-32 and a network hardware component 34. The wireless communication devices 18-32 may be laptop host computers 18 and 26, personal digital assistant hosts 20 and 30, personal computer hosts 24 and 32 and/or cellular telephone hosts 22 and 28. The details of the wireless communication devices will be described in greater detail with reference to FIG. 2. The base stations or access points 12-16 are operably coupled to the network hardware 34 via local area network connections 36, 38 and 40. The network hardware 34, which may be a router, switch, bridge, modem, system controller, et cetera provides a wide area network connection 42 for the communication system 10. Each of the base stations or access points 12-16 has an associated antenna or antenna array to communicate with the wireless communication devices in its area. Typically, the wireless communication devices register with a particular base station or access point 12-14 to receive services from the communication system 10. For direct connections (i.e., point-to-point communications), wireless communication devices communicate directly via an allocated channel. Typically, base stations are used for cellular telephone systems and like-type systems, while access points are used for in-home or in-building wireless networks. Regardless of the particular type of communication system, each wireless communication device includes a built-in radio and/or is coupled to a radio. The radio includes a highly linear amplifier and/or programmable multi-stage amplifier as disclosed herein to enhance performance, reduce costs, reduce size, and/or enhance broadband applications. FIG. 2 is a schematic block diagram illustrating a wireless communication device that includes the host device 18-32 and an associated radio 60. For cellular telephone hosts, the radio 60 is a built-in component. For personal digital assistants hosts, laptop hosts, and/or personal computer hosts, the radio 60 may be built-in or an externally coupled component. As illustrated, the host device 18-32 includes a processing module 50, memory 52, radio interface 54, input interface 58 and output interface 56. The processing module 50 and memory 52 execute the corresponding instructions that are typically done by the host device. For example, for a cellular telephone host device, the processing module 50 performs the corresponding communication functions in accordance with a particular cellular telephone standard. The radio interface 54 allows data to be received from and sent to the radio 60. For data received from the radio 60 (e.g., inbound data), the radio interface 54 provides the data to the processing module 50 for further processing and/or routing to the output interface 56. The output interface 56 provides connectivity to an output display device such as a display, monitor, speakers, et cetera such that the received data may be displayed. The radio interface 54 also provides data from the processing module 50 to the radio 60. The processing module 50 may receive the outbound data from an input device such as a keyboard, keypad, microphone, et cetera via the input interface 58 or generate the data itself. For data received via the input interface 58, the processing module 50 may perform a corresponding host function on the data and/or route it to the radio 60 via the radio interface 54. Radio 60 includes a host interface 62, digital receiver processing module 64, an analog-to-digital converter 66, a filtering/gain module 68, an IF mixing down conversion stage 70, a receiver filter 71, a low noise amplifier 72, a transmitter/receiver switch 73, a local oscillation module 74, memory 75, a digital transmitter processing module 76, a digital-to-analog converter 78, a filtering/gain module 80, an IF mixing up conversion stage 82, a power amplifier 84, a transmitter filter module 85, and an antenna 86. Note that the filter/gain module 80, the up-conversion module 82, the power amplifier 84, and the transmit filter module 85 comprises an RF modulation module of the radio. The antenna 86 may be a single antenna that is shared by the transmit and receive paths as regulated by the Tx/Rx switch 73, or may include separate antennas for the transmit path and receive path. The antenna implementation will depend on the particular standard to which the wireless communication device is compliant. The digital receiver processing module 64 and the digital transmitter processing module 76, in combination with operational instructions stored in memory 75, execute digital receiver functions and digital transmitter functions, respectively. The digital receiver functions include, but are not limited to, digital intermediate frequency to baseband conversion, demodulation, constellation demapping, decoding, and/or descrambling. The digital transmitter functions include, but are not limited to, scrambling, encoding, constellation mapping, modulation, and/or digital baseband to IF conversion. The digital receiver and transmitter processing modules 64 and 76 may be implemented using a shared processing device, individual processing devices, or a plurality of processing devices. Such a processing device may be a microprocessor, micro-controller, digital signal processor, microcomputer, central processing unit, field programmable gate array, programmable logic device, state machine, logic circuitry, analog circuitry, digital circuitry, and/or any device that manipulates signals (analog and/or digital) based on operational instructions. The memory 75 may be a single memory device or a plurality of memory devices. Such a memory device may be a read-only memory, random access memory, volatile memory, non-volatile memory, static memory, dynamic memory, flash memory, and/or any device that stores digital information. Note that when the processing module 64 and/or 76 implements one or more of its functions via a state machine, analog circuitry, digital circuitry, and/or logic circuitry, the memory storing the corresponding operational instructions is embedded with the circuitry comprising the state machine, analog circuitry, digital circuitry, and/or logic circuitry. In operation, the radio 60 receives outbound data 94 from the host device via the host interface 62. The host interface 62 routes the outbound data 94 to the digital transmitter processing module 76, which processes the outbound data 94 in accordance with a particular wireless communication standard (e.g., IEEE 802.11 Bluetooth, et cetera) to produce digital transmission formatted data 96. The digital transmission formatted data 96 will be a digital base-band signal or a digital low IF signal, where the low IF typically will be in the frequency range of one hundred kilohertz to a few megahertz. The digital-to-analog converter 78 converts the digital transmission formatted data 96 from the digital domain to the analog domain. The filtering/gain module 80 filters and/or adjusts the gain of the analog signal prior to providing it to the IF mixing stage 82. The IF mixing stage 82 converts the analog baseband or low IF signal into an RF signal based on a transmitter local oscillation 83 provided by local oscillation module 74. The power amplifier 84 amplifies the RF signal to produce outbound RF signal 98, which is filtered by the transmitter filter module 85. The antenna 86 transmits the outbound RF signal 98 to a targeted device such as a base station, an access point and/or another wireless communication device. The radio 60 also receives an inbound RF signal 88 via the antenna 86, which was transmitted by a base station, an access point, or another wireless communication device. The antenna 86 provides the inbound RF signal 88 to the receiver filter module 71 via the Tx/Rx switch 73, where the Rx filter 71 bandpass filters the inbound RF signal 88. The Rx filter 71 provides the filtered RF signal to low noise amplifier 72, which amplifies the signal 88 to produce an amplified inbound RF signal. The low noise amplifier 72 provides the amplified inbound RF signal to the IF mixing module 70, which directly converts the amplified inbound RF signal into an inbound low IF signal or baseband signal based on a receiver local oscillation 81 provided by local oscillation module 74. The down conversion module 70 provides the inbound low IF signal or baseband signal to the filtering/gain module 68. The filtering/gain module 68 filters and/or gains the inbound low IF signal or the inbound baseband signal to produce a filtered inbound signal. The analog-to-digital converter 66 converts the filtered inbound signal from the analog domain to the digital domain to produce digital reception formatted data 90. The digital receiver processing module 64 decodes, descrambles, demaps, and/or demodulates the digital reception formatted data 90 to recapture inbound data 92 in accordance with the particular wireless communication standard being implemented by radio 60. The host interface 62 provides the recaptured inbound data 92 to the host device 18-32 via the radio interface 54. As one of average skill in the art will appreciate, the wireless communication device of FIG. 2 may be implemented using one or more integrated circuits. For example, the host device may be implemented on one integrated circuit, the digital receiver processing module 64, the digital transmitter processing module 76 and memory 75 may be implemented on a second integrated circuit, and the remaining components of the radio 60, less the antenna 86, may be implemented on a third integrated circuit. As an alternate example, the radio 60 may be implemented on a single integrated circuit. As yet another example, the processing module 50 of the host device and the digital receiver and transmitter processing modules 64 and 76 may be a common processing device implemented on a single integrated circuit. Further, the memory 52 and memory 75 may be implemented on a single integrated circuit and/or on the same integrated circuit as the common processing modules of processing module 50 and the digital receiver and transmitter processing module 64 and 76. FIG. 3 is a schematic block diagram of the digital transmitter processing module 76 and the digital-to-analog converter 78. In this embodiment, the digital transmitter processing module 76 includes a digital baseband encoding module 100, an Inverse Fast Fourier Transform (IFFT) module 102 and a complex digital filter 104. The digital-to-analog converter 78 is a complex digital-to-analog converter and includes an in-phase digital-to-analog converter 78-I and a quadrature digital-to-analog converter 78-Q. The digital baseband encoding module performs a baseband encoding protocol, such as BPSK OFDM, QPSK OFDM, 16 QAM OFDM, and/or 64 QAM OFDM. In particular, the digital baseband encoding module 100 may include a forward error correction coder and an interleaving and mapping module to produce outbound symbols 108. The IFFT module 102 converts the outbound symbols 108 into complex time domain sample sequence 110. The functionality of an inverse fast Fourier transform is known, thus, no further discussion will be presented except to further illustrate the concepts of the present invention. The complex digital filter 104, which may be a low pass filter and/or bandpass filter and will be described in greater detail with reference to FIGS. 4 and 5, filters the complex time domain sample sequence 10 to produce filtered complex time domain sample sequence 112. In general, the complex digital filter 104 is a low pass filter to provide further attenuation of frequencies outside the bands of interest (i.e., filters undesired channels and passes the desired channel). For instance, the complex digital filter 104 provides a faster roll-off of the channels at the boundaries of the frequency spectrum such that when the in-phase and quadrature components are converted into radio frequency signals, the out-of-band signal strength is at or below the required signal strength of the exclusion bands for non-prescribed transmissions. The complex digital-to-analog converters 78-I and 78-Q convert the filtered complex time domain sample sequence 112 into in-phase analog signal components (I) and quadrature analog signal components (Q). FIG. 4 illustrates a schematic block diagram of the complex digital filter 104, which may be implemented as a multi-order elliptical low pass filter. The complex digital filter 104 includes three second-order bi-quad stages 120, 122, and 124 and a gain module 126. The gain module 126 includes a multiplier 127 and a right-shift module 128 to produce the filtered complex time domain sample sequence 112. In operation, the first second-order bi-quad stage 120 receives, in 8-bit words, the complex time domain sample sequence 110 and filters it to produce an 8-bit filtered sample. The 8-bit filtered sample is passed to the second stage 122 and the third stage 124, which further filters the signal to produce a multi-stage filtered 8-bit sample. The gain module 126 multiplies the 8-bit multi-ordered filtered 8-bit sample with a gain value, which is then subsequently right-shifted to produce the desired gain level for the filtered complex time domain sample sequence 112. As one of average skill in the art will appreciate, other embodiments may be used to produce the complex digital filter 104. For instance, a multi-order Chebychev low pass filter. FIG. 5 is schematic block diagram of one of the bi-quad stages 120, 122, or 124. As shown, the bi-quad stage includes a plurality of multipliers, a plurality of right-shift modules (>>Sn), adders, and latches. The coefficients for each stage includes B0,k, B1,k, B2,k, A1,k, and A2,k. FIG. 5 also illustrates the particular coefficient values for one embodiment of the filter. FIG. 6 is a schematic block diagram of an alternate embodiment of the digital transmit processing module 76 coupled to the complex digital-to-analog converters 78-I and 78-Q. In this embodiment, the digital transmit processing module 76 includes the digital baseband encoding module 100, a digital filter 130 and the inverse fast Fourier transform module 102. In this embodiment, the digital baseband encoding module 100 converts outbound data 94 into outbound symbols 108 in accordance with a baseband encoding protocol prescribed by a particular standard (e.g., IEEE 802.11(g)). The digital filter 130, which may be a frequency domain window based IFFT shaping form, filters the outbound symbols 108 to produce filtered outbound symbols 132. The frequency response of the digital filter 130 is such that when the filtered outbound symbols 132 are converted to radio frequency signals, the signal strength in the exclusion frequency bands are at or below the specified levels for non-licensed transmissions. The IFFT module 102 converts the filtered outbound symbols 130 into complex time domain sample sequence 134. The complex digital-to-analog converters 78-I and 78-Q convert the complex time domain sample sequence 134 into in-phase analog signal components (I) and quadrature analog signal components (Q). As one of average skill in the art will appreciate, the term “substantially” or “approximately”, as may be used herein, provides an industry-accepted tolerance to its corresponding term. Such an industry-accepted tolerance ranges from less than one percent to twenty percent and corresponds to, but is not limited to, component values, integrated circuit process variations, temperature variations, rise and fall times, and/or thermal noise. As one of average skill in the art will further appreciate, the term “operably coupled”, as may be used herein, includes direct coupling and indirect coupling via another component, element, circuit, or module where, for indirect coupling, the intervening component, element, circuit, or module does not modify the information of a signal but may adjust its current level, voltage level, and/or power level. As one of average skill in the art will also appreciate, inferred coupling (i.e., where one element is coupled to another element by inference) includes direct and indirect coupling between two elements in the same manner as “operably coupled”. As one of average skill in the art will further appreciate, the term “compares favorably”, as may be used herein, indicates that a comparison between two or more elements, items, signals, etc., provides a desired relationship. For example, when the desired relationship is that signal 1 has a greater magnitude than signal 2, a favorable comparison may be achieved when the magnitude of signal 1 is greater than that of signal 2 or when the magnitude of signal 2 is less than that of signal 1. The preceding discussion has presented a radio frequency transmitter that includes out-of-band attenuation. By including a digital filter within the digital transmit processing module, additional attenuation is achieved at RF for out-of-band frequencies while having negligible effect on signal strength of RF signals within the desired frequency bands. As one of average skill in the art will appreciate, other embodiments may be derived from the teaching of the present invention without deviating from the scope of the claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Technical Field of the Invention This invention relates generally to wireless communication systems and, more particularly, to radio frequency transmitters used within such systems. 2. Description of the Related Art As is known, use of frequencies for wireless communications is partitioned into frequency bands by government agencies. For instance, the Federal Communications Commission (FCC) defines, for the United States, frequency bands for specific uses and for which an FCC license is required (e.g., radio transmissions, television transmissions, etc.) and also defines frequency bands that are unlicensed and, as such, can be used for a variety of applications. For instance, the FCC has defined several frequency bands in the radio frequency spectrum as being unlicensed. Such unlicensed frequency bands include 902-928 MHz, 2.4-2.483 GHz and 5.75-5.85 GHz, which are collectively referred to as the ISM (Industrial Scientific Medical) band. Currently, the ISM band is used for in-building and system applications (e.g., bar code readers), industrial microwave ovens, wireless patient monitors, and wireless local area networks (WLAN). As is also known, there are standard bodies that define standards for WLAN equipment within the ISM band. Such standards include, but are not limited to, Bluetooth, IEEE 802.11(a), IEEE 802.11(b), and IEEE 802.11(g). The IEEE 802.11(g) standard provides wireless LAN operation specifications in the 2.4-2.482 GHz band. Specification applies to both transmitters and receivers and defines data rates, modulation schemes, transmitter architectures, receiver architectures, etc. In general, the specified modulation schemes are based on Orthogonal Frequency Division Multiplexing (OFDM) which, for 802.11(g) divides the 2.4-2.482 GHz band into a plurality of channels. Further, as specified, the channels at the boundaries of the frequency band (e.g., channels 1 and 11 that are centered at 2.412 GHz and 2.462 GHz, respectively) are preferred channels of use. As is further known, the FCC has defined exclusion frequency bands around the 2.4-2.482 GHz frequency band. One exclusion frequency band begins at 2.390 GHz and includes lower frequencies and the other exclusion frequency band begins at 2.4835 GHz and includes higher frequencies. An issue arises when fabricating a transmitter in accordance with the architecture defined within the 802.11(g) specification, in that, for channels 1 and 11, the transmit power levels in the exclusion frequency bands are too great, which violates the FCC restrictions on use of the exclusion frequency bands. Therefore, a need exists for a transmitter that provides desired power levels within prescribed frequency bands of operation and does not violate transmit power levels in non-prescribed frequency bands. | <SOH> BRIEF SUMMARY OF THE INVENTION <EOH>The RF transmitter having out-of-band attenuation of the present invention substantially meets these needs and others. In one embodiment, a radio frequency transmitter includes a digital baseband and coding module, an inverse fast Fourier transform (IFFT) module, a complex digital filter, a complex digital-to-analog converter and a radio frequency modulation module. The digital baseband and coding module is operably coupled to convert outbound data into outbound symbols in accordance with a baseband encoding protocol (e.g., binary phase shift keying (BPSK), orthogonal frequency division multiplexing (OFDM), quadrature phase shift keying (QPSK), 16 quadrature amplitude modulation (QAM) OFDM, and/or 64 QAM OFDM). The inverse fast Fourier transform module is operably coupled to convert the outbound symbols into a complex time domain sample sequence. The complex digital filter is operably coupled to filter the complex time domain sequence to produce a filtered complex time domain sample sequence. The complex digital-to-analog converter is operably coupled to convert the filtered complex time domain sample sequence into in-phase analog signal components and quadrature analog signal components. The radio frequency modulation module is operably coupled to convert the in-phase and quadrature analog signal components into outbound radio frequency signals. As configured, the complex digital filter attenuates the complex time domain sample sequence such that signal strength of the outbound radio frequency signals in an exclusion radio frequency band is at or below a specified signal strength with negligible attenuation on in-band signal strength. In another embodiment, a radio frequency transmitter includes a digital baseband encoding module, a digital filter, an inverse fast Fourier transform module, a complex digital-to-analog converter, and a radio frequency modulation module. The digital baseband and coding module is operably coupled to convert outbound data into outbound symbols in accordance with a baseband encoding protocol. The digital filter is operably coupled to filter the outbound symbols to produce filtered outbound symbols. The inverse fast Fourier transform module is operably coupled to convert the filtered outbound symbols into a complex time domain sample sequence. The complex digital-to-analog converter is operably coupled to convert the complex time domain sample sequence into in-phase analog signal components and quadrature analog signal components. The radio frequency modulation module is operably coupled to convert the in-phase and quadrature analog signal components into outbound radio frequency signals. The complex digital filter is operably to attenuate the complex time domain sample sequence such that signal strength of the outbound radio frequency signals in an exclusion radio frequency band is at or below a specified signal strength while having negligible attenuation on the signal strength within a desired frequency band. | 20040115 | 20070220 | 20050721 | 70059.0 | 0 | LE, NHAN T | RF TRANSMITTER HAVING IMPROVED OUT OF BAND ATTENUATION | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,757,983 | ACCEPTED | Foldable keyboard for mobile communication device | A mobile communication device has a full function keyboard constructed in two positions wherein the first portion may be pivoted and the second portion may be moved linearly sideways between respective open and closed positions one in which the keyboard is hidden and the keypad of the device is exposed for normal use and a second in which a larger viewing area of the display screen is revealed and the two portions of the keyboard are positioned on opposite sides of the screen of the device. | 1. An electronic device for operation in multiple applications comprising: a main body element having upper and lower faces relative to usage; a screen constructed in at least a first portion of the upper face of said main body element to provide a visible display of information to the user; a first panel mounted on the main body element for pivotal motion thereon between open and closed positions, said first panel having first and second faces, said first face accessible to the user in said closed position and said second face accessible to the user in said open position; a second panel mounted on the main body element for sideways rectilinear motion thereon and relative thereto between open and closed positions, said second panel having a third face, said third face accessible to the user in said open position and inaccessible to the user in said closed position; said first and second panels are in overlapping alignment with one another in the closed position; a function keyboard constructed in two portions, a first portion constructed in the second face of said first panel and a second portion constructed in said third face of said second panel, each of said function keyboard portions having an array of keys consistent with a selected function; said function keyboard is exposed for operative use in said open position wherein said first and second panels are in non-overlapping alignment with one another in said open position and said first and second panels are located on opposite sides of said screen in said open position wherein an additional portion of the upper face of said main body element located beneath and substantially covered by said second panel in said closed position is revealed and accessible to the user in said open position. 2. The electronic device for operation in multiple applications as defined in claim 1, wherein said first panel is manually rotatable about its pivotal axis. 3. The electronic device for operation in multiple applications as defined in claim 1, wherein said second panel is manually moved sideways. 4. The electronic device for operation in multiple applications as defined in claim 1 arranged for semi-automatic operation wherein said first panel is bias assisted between its respective said closed and open position. 5. The electronic device for operation in multiple applications as defined in claim 1 arranged for semi-automatic operation wherein said second panel is bias assisted between its respective said closed and open position. 6. The electronic device for operation in multiple applications as defined in claim 1 arranged for semi-automatic operation wherein said first and second panels are mechanically linked such that rotational movement of said first panel about its pivotal axis causes sideways linear movement of said second panel. 7. The electronic device for operation in multiple applications as defined in claim 1, wherein said second panel is inhibited for sideways movement and said first panel rotates about its pivotal axis between said open and closed positions. 8. The electronic device for operation in multiple applications as defined in claim 1, wherein said additional portion of the upper face of said main body element carries an additional array of keys consistent with a selected function. 9. The electronic device for operation in multiple applications as defined in claim 1, wherein said screen is constructed in said at least first portion and said additional portion of said upper face and defining a full screen wherein said first and second panels are in overlapping alignment with one another and the portion of said screen located in said additional portion of said upper face whereby the visible area for display of information is restricted to less than the full screen and wherein said full screen area is available for visible display of information to the user in said open position. 10. The electronic device for operation in multiple applications as defined in claim 1, wherein said function keyboard comprises a full function QWERTY key array split in first and second portions constructed respectively in said first and second panels. 11. The electronic device for operation in multiple applications as defined in claim 1, wherein said function keyboard comprises a game controller with multiple function keys divided between said first and second panels. 12. The electronic device for operation in multiple applications as defined in claim 1, wherein said array of keys on said faces of said panels are offset to prevent interference between the keys of said faces in said closed position. 13. The electronic device for operation in multiple applications as defined in claim 1, wherein said device is a mobile communication device and further comprises a communication keypad constructed on said first face of said first panel, said keypad being exposed for operative use in said closed position. 14. The electronic device for operation in multiple applications as defined in claim 10, further including a control unit, said control unit further operating to rotate the orientation of the display on said screen consistent with the functional position of said first and second panels so that said display is aligned with said communication keypad in said closed position and aligned with said functional keyboard in said open position. 15. The electronic device for operation in multiple applications as defined in claim 11, wherein said display on said screen is rotated 90° between said open and closed positions. 16. The electronic device for operation in multiple applications as defined in claim 12, wherein said orientation is controlled by the position of said first panel. 17. The electronic device for operation in multiple applications as defined in claim 12, wherein said orientation is controlled by the position of said second panel. 18. The electronic device for operation in multiple applications as defined in claim 10, wherein said communication device keypad is locked in an inoperative mode in said open position. 19. A function keyboard for use in a mobile communications device, said communications device having a main body element, a communications keypad, and a screen for displaying information to the user, said keyboard comprising: a first panel mounted on the main body element having upper and lower surfaces for pivotal motion thereon between open and closed positions, said first panel having first and second faces wherein said communications keypad is constructed on said first panel, said communications keypad being exposed for operative use in said closed position; a second panel mounted on the main body element for sideways rectilinear motion thereon and relative thereto between open and closed positions, said second panel having a third face, said third face accessible to the user in said open position and inaccessible to the user in said closed position; wherein said function keyboard is constructed in two portions, a first portion constructed in the second face of said first panel and a second portion constructed in said third face of said second panel, each of said function keyboard portions having an array of keys consistent with a selected function; wherein said function keyboard is exposed for operative use in said open position and said first and second panels are in overlapping alignment with one another in the closed position, and wherein said first and second panels are in non-overlapping alignment with one another in said open position and said first and second panels are located on opposite sides of said screen in said open position wherein an additional portion of the upper face of said main body element located beneath and substantially covered by said second panel in said closed position is revealed and accessible to the user in said open position. 20. A mobile communications device for operation in multiple applications comprising: a main body element having upper and lower faces relative to usage; a screen constructed in at least a first portion of the upper face of said main body element to provide a visible display of information to the user; a first panel mounted on the main body element for pivotal motion thereon between open and closed positions, said first panel having first and second faces, said first face accessible to the user in said closed position and said second face accessible to the user in said open position; a second panel mounted on the main body element for sideways rectilinear motion thereon and relative thereto between open and closed positions, said second panel having a third face, said third face accessible to the user in said open position and inaccessible to the user in said closed position; said first and second panels are in overlapping alignment with one another in the closed position; a communication keypad constructed on said first face of said first panel, said keypad being exposed for operative use in said closed position. a function keyboard constructed in two portions, a first portion constructed in the second face of said first panel and a second portion constructed in said third face of said second panel, each of said function keyboard portions having an array of keys consistent with a selected function; said function keyboard is exposed for operative use in said open position wherein said first and second panels are in non-overlapping alignment with one another in said open position and said first and second panels are located on opposite sides of said screen in said open position wherein an additional portion of the upper face of said main body element located beneath and substantially covered by said second panel in said closed position is revealed and accessible to the user in said open position. 21. A function keyboard for use in an electronic device, said device having a main body element, and a screen for displaying information to the user, said keyboard comprising: a first panel mounted on the main body element having upper and lower surfaces for pivotal motion thereon between open and closed positions, said first panel having first and second faces; a second panel mounted on the main body element for sideways rectilinear motion thereon and relative thereto between open and closed positions, said second panel having a third face, said third face accessible to the user in said open position and inaccessible to the user in said closed position; wherein said function keyboard is constructed in two portions, a first portion constructed in the second face of said first panel and a second portion constructed in said third face of said second panel, each of said function keyboard portions having an array of keys consistent with a selected function, wherein said function keyboard is exposed for operative use in said open position, and wherein said first and second panels are in overlapping alignment with one another in the closed position, and wherein said first and second panels are in non-overlapping alignment with one another in said open position and said first and second panels are located on opposite sides of said screen in said open position wherein an additional portion of the upper face of said main body element located beneath and substantially covered by said second panel in said closed position is revealed and accessible to the user in said open position. 22. A function keyboard for use in an electronic device, said device having a main body element, and a screen for displaying information to the user, said keyboard as defined in claim 17, wherein rotational movement of said first panel about its pivotal axis causes sideways linear movement of said second panel. 23. A function keyboard for use in an electronic device, said device having a main body element, and a screen for displaying information to the user, said keyboard as defined in claim 17, wherein sideways linear movement of said second panel causes rotational movement of said first panel about its pivotal axis. 24. A function keyboard for use in an electronic device, said device having a main body element, and a screen for displaying information to the user, said keyboard as defined in claim 17, wherein said second panel is inhibited for sideways movement whereby said first panel rotates about its pivotal axis between said open and closed positions. 25. A function keyboard for use in an electronic device, said device having a main body element, and a screen for displaying information to the user, said keyboard as defined in claim 17, wherein said additional portion of the upper face of said main body element carries an additional array of keys consistent with a selected function. 26. A function keyboard for use in an electronic device, said device having a main body element, and a screen for displaying information to the user, said keyboard as defined in claim 17, wherein said screen is constructed in said at least first portion and said additional portion of said upper face and defining a full screen wherein said first and second panels are in overlapping alignment with one another and the portion of said screen located in said additional portion of said upper face whereby the visible area for display of information is restricted to less than the full screen and wherein said full screen area is available for visible display of information to the user in said open position. 27. A function keyboard for use in an electronic device, said device having a main body element, and a screen for displaying information to the user, said keyboard as defined in claim 17, wherein said function keyboard comprises a full function QWERTY key array split in first and second portions constructed respectively in said first and second panels. 28. A function keyboard for use in an electronic device, said device having a main body element, and a screen for displaying information to the user, said keyboard as defined in claim 17, wherein said function keyboard comprises a game controller with multiple function keys divided between said first and second panels. 29. A function keyboard for use in an electronic device, said device having a main body element, and a screen for displaying information to the user, said keyboard as defined in claim 17, wherein said array of keys on said faces of said panels are offset to prevent interference between the keys of said faces in said closed position. 30. A function keyboard for use in an electronic device, said device having a main body element, and a screen for displaying information to the user, said keyboard as defined in claim 17, wherein said device is a mobile communication device and further comprises a communication keypad constructed on said first face of said first panel, said keypad being exposed for operative use in said closed position. 31. A function keyboard for use in an electronic device, said device having a main body element, and a screen for displaying information to the user, said keyboard as defined in claim 26, further including a control unit, said control unit further operating to rotate the orientation of the display on said screen consistent with the functional position of said first and second panels so that said display is aligned with said communication keypad in said closed position and aligned with said functional keyboard in said open position. 32. A function keyboard for use in an electronic device, said device having a main body element, and a screen for displaying information to the user, said keyboard as defined in claim 26, wherein said display on said screen is rotated 90° between said open and closed positions. 33. A function keyboard for use in an electronic device, said device having a main body element, and a screen for displaying information to the user, said keyboard as defined in claim 27, wherein said orientation is controlled by the position of said first panel. 34. A function keyboard for use in an electronic device, said device having a main body element, and a screen for displaying information to the user, said keyboard as defined in claim 27, wherein said orientation is controlled by the position of said second panel. 35. A function keyboard for use in an electronic device, said device having a main body element, and a screen for displaying information to the user, said keyboard as defined in claim 26, wherein said communication device keypad is locked in an inoperative mode in said open position. 36. An electronic device for operation in multiple applications comprising: a main body element having upper and lower faces relative to usage; a screen constructed in at least a first portion of the upper face of said main body element to provide a visible display of information to the user; a first panel mounted on the main body element for pivotal motion thereon between open and closed positions, said first panel having first and second faces, said first face accessible to the user in said closed position and said second face accessible to the user in said open position; a second panel mounted on the main body element for sideways rectilinear motion thereon and relative thereto between open and closed positions, said second panel having a third face, said third face accessible to the user in said open position and inaccessible to the user in said closed position; said first and second panels are in overlapping alignment with one another in the closed position; a function keyboard constructed in two portions, a first portion constructed in the second face of said first panel and a second portion constructed in said third face of said second panel, each of said function keyboard portions having an array of keys consistent with a selected function, and wherein said function keyboard is exposed for operative use in said open position wherein said function keyboard comprises a game controller with multiple function keys divided between said first and second panels. 37. An electronic device for operation in multiple applications comprising: a main body element having upper and lower faces relative to usage; a screen constructed in at least a first portion of the upper face of said main body element to provide a visible display of information to the user; a first panel mounted on the main body element for pivotal motion thereon between open and closed positions, said first panel having first and second faces, said first face accessible to the user in said closed position and said second face accessible to the user in said open position; a second panel mounted on the main body element for sideways rectilinear motion thereon and relative thereto between open and closed positions, said second panel having a third face, said third face accessible to the user in said open position and inaccessible to the user in said closed position; said first and second panels are in overlapping alignment with one another in the closed position; a function keyboard constructed in two portions, a first portion constructed in the second face of said first panel and a second portion constructed in said third face of said second panel, each of said function keyboard portions having an array of keys consistent with a selected function, and said function keyboard is exposed for operative use in said open position wherein said array of keys on said faces of said panels are offset to prevent interference between the keys of said faces in said closed position. 38. An electronic device for operation in multiple applications comprising: a main body element having upper and lower faces relative to usage; a screen constructed in at least a first portion of the upper face of said main body element to provide a visible display of information to the user; a first panel mounted on the main body element for pivotal motion thereon between open and closed positions, said first panel having first and second faces, said first face accessible to the user in said closed position and said second face accessible to the user in said open position; a second panel mounted on the main body element for sideways rectilinear motion thereon and relative thereto between open and closed positions, said second panel having a third face, said third face accessible to the user in said open position and inaccessible to the user in said closed position; said first and second panels are in overlapping alignment with one another in the closed position; a function keyboard constructed in two portions, a first portion constructed in the second face of said first panel and a second portion constructed in said third face of said second panel, each of said function keyboard portions having an array of keys consistent with a selected function wherein said function keyboard is exposed for operative use in said open position; wherein said device is a mobile communication device and further comprises a communication keypad constructed on said first face of said first panel, said keypad being exposed for operative use in said closed position, and further wherein said mobile communications device comprises a control unit, said control unit further operating to rotate the orientation of the display on said screen consistent with the functional position of said first and second panels so that said display is aligned with said communication keypad in said closed position and aligned with said functional keyboard in said open position. 39. The electronic device for operation in multiple applications as defined in claim 34 wherein said display on said screen is rotated 90° between said open and closed positions. 40. The electronic device for operation in multiple applications as defined in claim 34 wherein said orientation is controlled by the position of said first panel. 41. The electronic device for operation in multiple applications as defined in claim 34 wherein said orientation is controlled by the position of said second panel. 42. A function keyboard for use in an electronic device, said device having a main body element, and a screen for displaying information to the user, said keyboard comprising: a first panel mounted on the main body element having upper and lower surfaces for pivotal motion thereon between open and closed positions, said first panel having first and second faces; a second panel mounted on the main body element for sideways rectilinear motion thereon and relative thereto between open and closed positions, said second panel having a third face, said third face accessible to the user in said open position and inaccessible to the user in said closed position; wherein said function keyboard is constructed in two portions, a first portion constructed in the second face of said first panel and a second portion constructed in said third face of said second panel, each of said function keyboard portions having an array of keys consistent with a selected function, wherein said function keyboard is exposed for operative use in said open position, and wherein said portions of said function keyboard comprises a game controller with multiple function keys divided between said first and second panels. 43. A function keyboard for use in an electronic device, said device having a main body element, and a screen for displaying information to the user, said keyboard comprising: a first panel mounted on the main body element having upper and lower surfaces for pivotal motion thereon between open and closed positions, said first panel having first and second faces; a second panel mounted on the main body element for sideways rectilinear motion thereon and relative thereto between open and closed positions, said second panel having a third face, said third face accessible to the user in said open position and inaccessible to the user in said closed position; wherein said function keyboard is constructed in two portions, a first portion constructed in the second face of said first panel and a second portion constructed in said third face of said second panel, each of said function keyboard portions having an array of keys consistent with a selected function, wherein said function keyboard is exposed for operative use in said open position, and wherein said array of keys on said faces of said panels are offset to prevent interference between the keys of said faces in said closed position. 44. A function keyboard for use in an electronic device, said device having a main body element, and a screen for displaying information to the user, said keyboard comprising: a first panel mounted on the main body element having upper and lower surfaces for pivotal motion thereon between open and closed positions, said first panel having first and second faces; a second panel mounted on the main body element for sideways rectilinear motion thereon and relative thereto between open and closed positions, said second panel having a third face, said third face accessible to the user in said open position and inaccessible to the user in said closed position; wherein said function keyboard is constructed in two portions, a first portion constructed in the second face of said first panel and a second portion constructed in said third face of said second panel, each of said function keyboard portions having an array of keys consistent with a selected function, wherein said function keyboard is exposed for operative use in said open position, wherein said device is a mobile communication device and further comprises a communication keypad constructed on said first face of said first panel, said keypad being exposed for operative use in said closed position, and further wherein said mobile communications device comprises a control unit, said control unit further operating to rotate the orientation of the display on said screen consistent with the functional position of said first and second panels so that said display is aligned with said communication keypad in said closed position and aligned with said functional keyboard in said open position. 45. A function keyboard for use in an electronic device, said device having a main body element, and a screen for displaying information to the user, said keyboard as defined in claim 40, wherein rotational movement of said first panel about its pivotal axis causes sideways linear movement of said second panel. 46. A function keyboard for use in an electronic device, said device having a main body element, and a screen for displaying information to the user, said keyboard as defined in claim 40, wherein sideways linear movement of said second panel causes rotational movement of said first panel about its pivotal axis. 47. A function keyboard for use in an electronic device, said device having a main body element, and a screen for displaying information to the user, said keyboard as defined in claim 40 wherein said orientation is controlled by the position of said first panel. 48. A function keyboard for use in an electronic device, said device having a main body element, and a screen for displaying information to the user, said keyboard as defined in claim 40 wherein said orientation is controlled by the position of said second panel. | BACKGROUND OF THE INVENTION The present invention relates generally to electronic devices and deals more particularly with mobile communication devices specifically mobile telephones and similar communication devices of the type having keyboard functionality. Portable electronic devices particularly mobile telephones and similar communication devices have rapidly expanded in use and function as users have demanded increasing functionality. It is common to see mobile telephones that provide Global Computer Network access, messaging, personal information management, personal digital assistant functionality, music, facsimile, gaming, in addition to telephone communication. More complex keyboards have been provided to be compatible with the more complex applications that are found in such devices. One such full function keyboard arrangement is disclosed in U.S. Pat. No. 6,580,932, assigned to the same assignee as the present invention in which a foldable keyboard is provided wherein a panel has an inner and outer surface and rotates between two positions. The outer surface carries a communication keyboard and the inner surfaces carries a portion of the number of keys of the full function keyboard which keys are exposed for access and usage when the panel is rotated into an open position. The panel is in an overlapping position with a further fixed panel that carries the remaining portion of the number of keys of the keyboard on the fixed panel are exposed for access and usage when the rotated panel is in the open position. Although such devices are capable of providing more complex applications the display screen size remains fixed for both standard communication functionality and the advanced more complex functionalities. It would be desirable to provide a larger display screen size and a full function keyboard for such communication devices while maintaining the compact size required in the mobile communication device. It is an object of the present invention to provide a simple and inexpensive means of providing a full function keyboard and a larger display screen size to accommodate the more complex applications of a mobile communication device when operated in the non-communication functionality mode. SUMMARY OF THE INVENTION In accordance with a first aspect of the invention, an electronic device for operation in multiple applications reveals a larger screen display viewing area in the device open position and includes a main body element having upper and lower faces relative to usage wherein the screen is constructed in at least a first portion of the upper face of said main body element to provide a visible display of information to the user. A first panel having first and second faces is mounted on the main body element for pivotal motion thereon between the device open and closed positions. The first face is accessible to the user in the closed position and the second face is accessible to the user in said open position. A second panel having a third face is mounted on the main body element for sideways rectilinear motion thereon and relative thereto between the device open and closed positions. The third face is accessible to the user in the open position and inaccessible to the user in the closed position and the first and second panels are in overlapping alignment with one another in the device closed position. A function keyboard is constructed in two portions wherein a first is portion constructed in the second face of the first panel and a second portion is constructed in the third face of the second panel and each of the function keyboard portions has an array of keys consistent with a selected function, the function keyboard is exposed for operative use in the device open position wherein the first and second panels are in non-overlapping alignment with one another in the open position and the first and second panels are located on opposite sides of the screen in the open position wherein an additional portion of the upper face of the main body element located beneath and substantially covered by the second panel in the closed position is revealed and accessible to the user in the open position. The device moves between open and closed positions wherein the first panel is manually rotated about its pivotal axis and the second panel is manually moved sideways. Optionally, the device may operate semi-automatically wherein the first panel is manually rotated about is pivotal axis and the second panel is spring assisted to move between the closed position and open position. Optionally, the device may operate semi-automatically wheren the first panel is spring assisted to move between the closed position and the open position and the second panel is manually moved sideways. Optionally, both the first panel and second panel may be spring assisted to move between the closed position and the open position. The first and second panels may further be mechanically linked such that rotational movement of the first panel about its pivotal axis causes sideways linear movement of the second panel. The second panel may be optionally inhibited for sideways movement whereby only the first panel rotates about its pivotal axis between the open and closed positions and the second panel remains stationary. Optionally, the additional portion of the upper face of the main body element carries an additional array of keys consistent with a selected function. Preferably, the screen is constructed in at least the first portion and the additional portion of the upper face and defines a full screen wherein the first and second panels are in overlapping alignment with one another and the portion of the screen located in the additional portion of the upper face whereby the visible area for display of information is restricted to less than the full screen in the device closed position and wherein the full screen area is available for visible display of information to the user in the open position. Optionally, the function keyboard comprises a full function QWERTY key array split in the first and second portions constructed respectively in the first and second panels. Alternately, the function keyboard comprises a game controller with multiple function keys divided between the first and second panels or may be of any desired keyboard array. Preferably, the array of keys on the faces of the panels are offset to prevent interference between the keys of the faces in the device closed position. Optionally, the device is a mobile communication device and further comprises a communication keypad constructed on the first face of the first panel wherein the communication is exposed for operative use in the device closed position. Optionally, a control unit is provided and operates to rotate the orientation of the display on the screen consistent with the functional position of the first and second panels so that the display is aligned with the communication keypad in the device closed position and aligned with the functional keyboard in the device open position. Preferably, the display on the screen is rotated 90° between the open and closed positions, wherein the orientation is controlled by the position of the first panel or the position of the second panel. Preferably, the communication device keypad is locked in an inoperative mode in the device open position. In accordance with a second aspect of the invention, a function keyboard for use in a mobile communications device having a main body element, a communications keypad, and a screen for displaying information to the user is provided. A first panel having first and second faces is mounted on the main body element and has upper and lower surfaces for pivotal motion thereon between open and closed positions. The communications keypad is constructed on the first panel and is exposed for operative use in the device closed position. A second panel having a third face is mounted on the main body element for sideways rectilinear motion thereon and relative thereto between the device open and closed positions. The third face is accessible to the user in the device open position and inaccessible to the user in the device closed position; The function keyboard is constructed in two portions wherein a first portion is constructed in the second face of the first panel and a second portion is constructed in the third face of the second panel. Each of the function keyboard portions has an array of keys consistent with a selected function wherein the function keyboard is exposed for operative use in the device open position and the first and second panels are in overlapping alignment with one another in the device closed position. The first and second panels are in non-overlapping alignment with one another in the device open position and are located on opposite sides of the screen wherein an additional portion of the upper face of the main body element located beneath and substantially covered by the second panel in the device closed position is revealed and accessible to the user in the device open position. In accordance with a third aspect of the invention, a mobile communications device for operation in multiple applications is presented and comprises a main body element having upper and lower faces relative to usage and a screen constructed in at least a first portion of the upper face of the main body element to provide a visible display of information to the user. A first panel having first and second faces is mounted on the main body element for pivotal motion thereon between the device open and closed positions. The first face is accessible to the user in the device closed position and the second face is accessible to the user in the device open position. A second panel having a third face is mounted on the main body element for sideways rectilinear motion thereon and relative thereto between the device open and closed positions. The ,third face is accessible to the user in the device open position and inaccessible to the user in the device closed position wherein the first and second panels are in overlapping alignment with one another in the closed position. A communication keypad is constructed on the first face of the first panel and is exposed for operative use in the device closed position. A function keyboard is constructed in two portions, the first portion constructed in the second face of the first panel and a second portion constructed in the third face of the second panel, each of the function keyboard portions has an array of keys consistent with a selected function. The function keyboard is exposed for operative use in the device open position. The first and second panels are in non-overlapping alignment with one another in the device open position and are located on opposite sides of the screen wherein an additional portion of the upper face of the main body element located beneath and substantially covered by the second panel in the device closed position is revealed and accessible to the user in the device open position. In accordance with a fourth aspect of the invention, a function keyboard for use in an electronic device having a main body element, and a screen for displaying information to the user is presented wherein the keyboard includes a first panel having first and second faces mounted on the main body element having upper and lower surfaces for pivotal motion thereon between open and closed positions and a second panel having a third face mounted on the main body element for sideways rectilinear motion thereon and relative thereto between the device open and closed positions wherein the third face is accessible to the user in the device open position and inaccessible to the user in the device closed position. The function keyboard is constructed in two portions wherein a first portion is constructed in the second face of the first panel and a second portion is constructed in the third face of the second panel. Each of the function keyboard portions has an array of keys consistent with a selected function wherein said function keyboard is exposed for operative use in the device open position. The first and second panels are in overlapping alignment with one another in the device closed position and in non-overlapping alignment with one another in the device open position and the first and second panels are located on opposite sides of the screen in the device open position wherein an additional portion of the upper face of the main body element located beneath and substantially covered by the second panel in the device closed position is revealed and accessible to the user in the device open position. Preferably, the screen is constructed in the first portion and the additional portion of the upper face and defines a full screen wherein the first and second panels are in overlapping alignment with one another and the portion of the screen located in the additional portion of the upper face whereby the visible area for display of information is restricted to less than the full screen in the device closed position and wherein the full screen area is available for visible display of information to the user in the device open position. In accordance with a fifth aspect of the invention, an electronic device for operation in multiple applications is presented and includes a main body element having upper and lower faces relative to usage and a screen constructed in at least a first portion of the upper face of the main body element to provide a visible display of information to the user. A first panel having first and second face is mounted on the main body element for pivotal motion thereon between the device open and closed positions. The first face is accessible to the user in the device closed position and the second face is accessible to the user in the device open position. A second panel having a third face is mounted on the main body element for sideways rectilinear motion thereon and relative thereto between the device open and closed positions. The third face is accessible to the user in the device open position and inaccessible to the user in the device closed position and the first and second panels are in overlapping alignment with one another in the closed position. A function keyboard is constructed in two portions wherein a first portion is constructed in the second face of the first panel and a second portion constructed in the third face of the second panel. Each of the function keyboard portions has an array of keys consistent with a selected function. The function keyboard is exposed for operative use in the device open position wherein the function keyboard comprises a game controller with multiple function keys divided between the first and second panels. In accordance with a sixth aspect of the invention, an electronic device for operation in multiple applications includes a main body element having upper and lower faces relative to usage and a screen constructed in at least a first portion of the upper face of the main body element to provide a visible display of information to the user. A first panel having first and second faces is mounted on the main body element for pivotal motion thereon between the device open and closed positions. The first face is accessible to the user in the closed position and the second face is accessible to the user in the open position. A second panel having a third face is mounted on the main body element for sideways rectilinear motion thereon and relative thereto between open and closed positions. The third face is accessible to the user in the open position and inaccessible to the user in the closed position and the first and second panels are in overlapping alignment with one another in the closed position. A function keyboard is constructed in two portions wherein a first portion is constructed in the second face of the first panel and a second portion is constructed in the third face of the second panel. Each of the function keyboard portions has an array of keys consistent with a selected function, and is exposed for operative use in the device open position wherein the array of keys on the faces of the panels are offset to prevent interference between the keys of the faces in the device closed position. In accordance with a further aspect of the invention, an electronic device for operation in multiple applications is presented and includes a main body element having upper and lower faces relative to usage and a screen constructed in at least a first portion of the upper face of the main body element to provide a visible display of information to the user. A first panel having first and second faces is mounted on the main body element for pivotal motion thereon between open and closed positions. The first face is accessible to the user in the device closed position and the second face is accessible to the user in the device open position. A second panel having a third face is mounted on the main body element for sideways rectilinear motion thereon and relative thereto between the device open and closed positions. The third face is accessible to the user in the open position and inaccessible to the user in the closed position wherein the first and second panels are in overlapping alignment with one another in the closed position. A function keyboard is constructed in two portions wherein a first portion is constructed in the second face of the first panel and a second portion is constructed in the third face of the second panel. Each of the function keyboard portions has an array of keys consistent with a selected function wherein the function keyboard is exposed for operative use in the device open position and wherein the device is a mobile communication device and further comprises a communication keypad constructed on the first face of the first panel and is exposed for operative use in the closed position. The mobile communications device further includes a control unit that operates to rotate the orientation of the display on the screen consistent with the functional position of the first and second panels so that the display is aligned with the communication keypad in the device closed position and aligned with the functional keyboard in the device open position. In a yet further aspect of the invention, a function keyboard for use in an electronic device having a main body element, and a screen for displaying information to the user is presented wherein the keyboard includes a first panel having first and second faces mounted on the main body element having upper and lower surfaces for pivotal motion thereon between open and closed positions. A second panel having a third face is mounted on the main body element for sideways rectilinear motion thereon and relative thereto between open and closed positions. The third face is accessible to the user in the open position and inaccessible to the user in the closed position. The function keyboard is constructed in two portions wherein a first portion is constructed in the second face of the first panel and a second portion is constructed in the third face of the second panel. Each of the function keyboard portions has an array of keys consistent with a selected function and is exposed for operative use in the open position, and wherein the portions of the function keyboard include a game controller with multiple function keys divided between the first and second panels. DESCRIPTION OF THE DRAWINGS Other features, objects and advantages of the present invention will become readily apparent from the following written description of exemplary embodiments taken in connection with the figures wherein: FIG. 1 is a somewhat schematic perspective view of a mobile communication device embodying the present invention; FIG. 2 is a somewhat schematic view of the mobile communication device of FIG. 1 showing the first panel in an intermediate rotated position and the second panel moved linearly away from the main body as it might be between open and closed positions; FIG. 3 is a somewhat schematic top view of the mobile communication device of FIG. 1 in the fully open position revealing the full display screen of the device; FIG. 4a is a schematic illustration if the display orientation in the device closed position; FIG. 4b is a schematic illustration of the display orientation in the device closed position; FIG. 5 is a block diagram of the control system of a mobile communication device embodying the present invention; FIG. 6 is a somewhat schematic top view of an alternate embodiment of the present invention; FIG. 7 is a schematic illustration of the mobile communication device of FIG. 1 with a bias assisted second panel for semi-automatic operation between the closed and open position; FIG. 8 is a schematic illustration of the mobile communication device of FIG. 1 with a bias assisted first panel for semi-automatic operation between the closed and open position; and FIG. 9 is a schematic illustration of the mobile communication device of FIG. 1 wherein the first panel and second panel are mechanically linked for movement with one another between the closed and open positions. DESCRIPTION OF PREFERRED EMBODIMENTS Turning now to the drawings an illustrative embodiment of the present invention is shown in FIGS. 1-3 for purposes of illustration as a mobile communication device and is generally designated 10. Although the invention is described as a mobile communication device such as a mobile telephone, the invention is applicable to other electronic devices such as pagers, game units, music players and the like. As illustrated in FIG. 1, the mobile phone 10 is shown in a first position referred to as the fully closed position and is constructed having a main body element 12. The main body element 12 includes encloses a screen 14 a portion of which generally designated 16 is viewable in the closed position and provides a display 18 for communicating pertinent information to the user in response to actions by the user. As best viewed in FIGS. 2 and 3, the mobile telephone is constructed having two panels 20 and 22 which are mounted on the main body element 12. The first panel 20 is mounted on the main body element 12 and is rotatable about an axis X-X as shown in FIGS. 1, 2 and 3. The second panel 22 is mounted on the main body element 12 and arranged for slidable engagement with the body element relative to the body element between the closed position and the open position in the direction indicated by the direction arrow 30 as shown in FIGS. 2 and 3. In the closed position, the panel 20 is rotated into overlapping alignment with the panel 22 as shown in FIG. 1. The rotating panel 20 has two oppositely disposed faces 24 and 26. Face 26 is the inner face when the panel 20 is in the closed position and face 24 is the outer face in the closed position. In the illustrated embodiment, face 24 contains a communications keypad such as a standard telephone keypad generally designated 32 for use when the mobile phone 10 is operating in the standard communication mode. In the closed position, the mobile phone 10 operates as a standard operating mobile telephone with the display 18 of screen 14 oriented in alignment with the keypad 32 in a well known conventional manner. The second panel 22 has a face 28 which is exposed as the outer face when the panel 22 moves to its operative position as illustrated in FIG. 3 when the mobile phone 10 is in the open position. The panel 22 moves along a rectilinear path to one side 34 of the screen 14 as the panel 20 is rotated to the mobile phone open position as illustrated in FIG. 3 at the end 36 of the screen 14 opposite the screen end 34. In one embodiment, the first panel 20 is manually rotated about its axis X-X to its open position and the second panel 22 is manually moved sideways along the rectilinear path in the direction indicated by the direction arrow 30. In this embodiment, the first panel 20 is moved to its open position prior to the second panel 22 being moved to its open position, and the second panel 22 is moved to its closed position prior to the first panel being rotated to its closed position. In an alternate embodiment, the device 10 may operate semi-automatically wherein the first panel 20 is manually rotated about its pivot axis X-X to the open position and the second panel 22 is biased or spring assisted to mvoe between the closed position and its open position utilizing any suitable biasing means well known to those skilled in the art to carry out the intended function. For example, as illustrated schematically in FIG. 7, a coil spring 90 is in an uncompressed state and shown in a slot 92 and has one end 94 in contact with a stop 96 and its opposite end 98 in contact with the end 100 of the second panel 22. The spring 90 is in a compressed state when the second panel 22 is in the closed position and may be held in the closed position by any suitable means such as a releaseable button 102 that cooperates with the main body element 12 to hold the second panel 222 in its closed position and the spring 90 in its compressed state. When the releaseable button 102 is operated, the force of the compressed spring urges the second panel 22 toward its open position. In a further embodiment, the device 10 may operate semi-automatically wherein the first panel 20 is biased or spring assisted to move between its closed position to its open position utilizing any suitable biasing means well known to those skilled in the art to carry out the intended function. For example, as illustrated schematically in FIG. 8, a hairpin spring 110 is located with its opening about the pivot point of the first panel 20 and has one end 112 engaged with the body 12 and its other end 114 engaged with the arm of the first panel 20. The hairpin spring 110 compresses when the first panel 20 is moved to its closed position. When the first panel 20 is released, the end 114 of the hairpin spring 110 urges the panel in the direction of arrow 116 to rotate about its pivot axis to its open position. In another embodiment, the device 10 may oeprate semi-automatically wherein both the first panel 20 and the second panel 22 are biased or spring assisted to move between respective closed and open positions. In a still further embodiment, the panels 20 and 22 may be mechanically linked and arranged for cooperative movement with one another such that as the first panel 20 is rotated from the mobile phone closed position to the open position, the second panel 22 moves along the rectilinear path from the mobile phone closed position to the open position as illustrated in FIG. 3 and visa versa when the mobile phone moves from its open position to its closed position. A mechanically linked arrangement is shown schematically for example in FIG. 9 wherein a wheel gear 120 is attached to the arm of the first panel 20 at its pivot point. The second panel 22 includes a rack gear 122 at one end and the teeth of the rack gear cooperate with the teeth of the wheel gear such that rotation of the first panel 20 about is pivot axis causes sideways linear movement of the second panel 22 in the direction indicated by arrow 124. Thus, the second panel 22 is moved to its open position when the first panel 20 is rotated to its open position and the second panel 22 is moved to its closed position when the first panel 20 is rotated to its closed position. As best illustrated in FIG. 3, the full function keyboard is divided in half and arranged on the left and right keyboard portions 40 and 42. The left and right keyboard portions 40 and 42 carry the key and button array 44 used for the particular application wherein the key and button array is divided in half and arranged on the left and right keyboard portions 40 and 42, respectively. The keyboard is designed for thumb actuation by both hands which makes it convenient to hold the mobile phone 10 in both hands and operate the keyboard portions 40 and 42 accurately and efficiently. As best illustrated in FIG. 3, the left-hand keyboard portion 40 is constructed on the face 26 of the rotating panel 20 on the opposite side of the communication keypad 32. The right-hand keyboard portion 42 is constructed on the upper face 28 of the panel 22. To insure a compact overlapping engagement of the panels 20 and 22 in the mobile phone closed position, the portions of the key array 44 on the opposing panel faces 26 and 28 are offset to avoid interference in the closed position. Alternately, the height or depth of the keys are such that there is sufficient clearance when the panels 20 and 22 are in the closed position. In the mobile phone open position, an additional area or portion 46 of the screen 14 carried in the upper face of the main body element which in the closed position is located beneath and substantially covered by the panel 22 in the closed position is revealed to provide a substantially larger viewing area of the display 18. The portions 16 and 46 define a full screen area for visible display of information to the user when the phone is in the open position. The benefits of a larger screen display viewing area are apparent since additional information may be provided to the user without scrolling or jumping from screen to screen. A larger screen viewing area such as provided by the present invention is also beneficial to game playing or viewing website information such as downloadable from the global computer network in a manner well known to those skilled in the art. The display 18 of the screen 14 is controlled for orientation in the two positions depending upon the mode of use. For example, in the mobile phone closed position, the display 18 is oriented in alignment with the communication keypad 32 while in the mobile phone open position, the display 18 is aligned with the function key array 44. As illustrated in FIGS. 4a and 4b, the display orientation is rotated ninety degrees between the mobile phone communication mode in which the panels 20 and 22 are in the closed position to the full function mode wherein the panels 20 and 22 are in the mobile phone open position. The orientation of a display and other operative functions of the mobile phone 10 are carried out by means of a system control unit such as illustrated in the schematic functional block diagram in FIG. 5. A panel position indicator 52 provides a signal to the device control unit 54 in response to the panel 20 and/or panel 22 being in the mobile phone opened or closed position. The device control unit 54 may be a microprocessor, digital signal processor, a display driver or other means including both the hardware and software for carrying out the control function as well known by those skilled in the art. The device control unit 54 may likewise be manually operated by the user and which provides a device function input 56 by means of a key or other operative stimulus. The device function signal is coupled to the device control unit 54. The device control unit 54 provides an output signal corresponding to the desired orientation of the display to a display orientation and control unit 58 to orient the position of the display 60 as needed. The panel position sensor and indicator 52 may likewise provide an output signal to enable or disable the keys of the communication keypad 32 by operation of a communication keypad lock 62. Turning to FIG. 6, a somewhat schematic top view of an alternate embodiment of the present invention is illustrated therein and generally designated 80 wherein a game controller keypad is provided rather than a full function keyboard. The game keyboard comprises a set of action keys generally designated 82 constructed on the face 28 of the panel 22. A motion pad or joystick generally designated 84 is constructed on the face 26 of the panel 20. In the closed position, the panel 22 moves along a rectilinear path in the direction of the direction arrow 30 covering the portion of the screen 14 as the panel 20 rotates about the axis X-X into an overlapping alignment with the panel 22 in the mobile phone closed position. The communication keypad 32 is constructed on the side opposite the face 26 of the panel 20 as discussed and described above. In a further embodiment, the device could be utilized without a communication keypad or communication capability and used as a game unit only. An electronic device for operation in multiple applications particularly useful as a mobile communication device has been disclosed above wherein the screen display size is increased in area from a portion of a display in the mobile phone closed position to a full screen display in the mobile phone opened position in which a rotating panel is at one side of the screen and a sliding panel is at the opposite side of the screen in the open position. The panels in the opened position can carry other desired key arrays consistent with a selected function such as other functional keyboards, game units or other operative devices. The screen display may be of any standard type including color well known to those skilled in the art. Accordingly, numerous changes, additions or modifications may be made by those skilled in the art without departing from the spirit and scope of the invention and, therefore, the invention has been presented by way of illustration rather than limitation. | <SOH> BACKGROUND OF THE INVENTION <EOH>The present invention relates generally to electronic devices and deals more particularly with mobile communication devices specifically mobile telephones and similar communication devices of the type having keyboard functionality. Portable electronic devices particularly mobile telephones and similar communication devices have rapidly expanded in use and function as users have demanded increasing functionality. It is common to see mobile telephones that provide Global Computer Network access, messaging, personal information management, personal digital assistant functionality, music, facsimile, gaming, in addition to telephone communication. More complex keyboards have been provided to be compatible with the more complex applications that are found in such devices. One such full function keyboard arrangement is disclosed in U.S. Pat. No. 6,580,932, assigned to the same assignee as the present invention in which a foldable keyboard is provided wherein a panel has an inner and outer surface and rotates between two positions. The outer surface carries a communication keyboard and the inner surfaces carries a portion of the number of keys of the full function keyboard which keys are exposed for access and usage when the panel is rotated into an open position. The panel is in an overlapping position with a further fixed panel that carries the remaining portion of the number of keys of the keyboard on the fixed panel are exposed for access and usage when the rotated panel is in the open position. Although such devices are capable of providing more complex applications the display screen size remains fixed for both standard communication functionality and the advanced more complex functionalities. It would be desirable to provide a larger display screen size and a full function keyboard for such communication devices while maintaining the compact size required in the mobile communication device. It is an object of the present invention to provide a simple and inexpensive means of providing a full function keyboard and a larger display screen size to accommodate the more complex applications of a mobile communication device when operated in the non-communication functionality mode. | <SOH> SUMMARY OF THE INVENTION <EOH>In accordance with a first aspect of the invention, an electronic device for operation in multiple applications reveals a larger screen display viewing area in the device open position and includes a main body element having upper and lower faces relative to usage wherein the screen is constructed in at least a first portion of the upper face of said main body element to provide a visible display of information to the user. A first panel having first and second faces is mounted on the main body element for pivotal motion thereon between the device open and closed positions. The first face is accessible to the user in the closed position and the second face is accessible to the user in said open position. A second panel having a third face is mounted on the main body element for sideways rectilinear motion thereon and relative thereto between the device open and closed positions. The third face is accessible to the user in the open position and inaccessible to the user in the closed position and the first and second panels are in overlapping alignment with one another in the device closed position. A function keyboard is constructed in two portions wherein a first is portion constructed in the second face of the first panel and a second portion is constructed in the third face of the second panel and each of the function keyboard portions has an array of keys consistent with a selected function, the function keyboard is exposed for operative use in the device open position wherein the first and second panels are in non-overlapping alignment with one another in the open position and the first and second panels are located on opposite sides of the screen in the open position wherein an additional portion of the upper face of the main body element located beneath and substantially covered by the second panel in the closed position is revealed and accessible to the user in the open position. The device moves between open and closed positions wherein the first panel is manually rotated about its pivotal axis and the second panel is manually moved sideways. Optionally, the device may operate semi-automatically wherein the first panel is manually rotated about is pivotal axis and the second panel is spring assisted to move between the closed position and open position. Optionally, the device may operate semi-automatically wheren the first panel is spring assisted to move between the closed position and the open position and the second panel is manually moved sideways. Optionally, both the first panel and second panel may be spring assisted to move between the closed position and the open position. The first and second panels may further be mechanically linked such that rotational movement of the first panel about its pivotal axis causes sideways linear movement of the second panel. The second panel may be optionally inhibited for sideways movement whereby only the first panel rotates about its pivotal axis between the open and closed positions and the second panel remains stationary. Optionally, the additional portion of the upper face of the main body element carries an additional array of keys consistent with a selected function. Preferably, the screen is constructed in at least the first portion and the additional portion of the upper face and defines a full screen wherein the first and second panels are in overlapping alignment with one another and the portion of the screen located in the additional portion of the upper face whereby the visible area for display of information is restricted to less than the full screen in the device closed position and wherein the full screen area is available for visible display of information to the user in the open position. Optionally, the function keyboard comprises a full function QWERTY key array split in the first and second portions constructed respectively in the first and second panels. Alternately, the function keyboard comprises a game controller with multiple function keys divided between the first and second panels or may be of any desired keyboard array. Preferably, the array of keys on the faces of the panels are offset to prevent interference between the keys of the faces in the device closed position. Optionally, the device is a mobile communication device and further comprises a communication keypad constructed on the first face of the first panel wherein the communication is exposed for operative use in the device closed position. Optionally, a control unit is provided and operates to rotate the orientation of the display on the screen consistent with the functional position of the first and second panels so that the display is aligned with the communication keypad in the device closed position and aligned with the functional keyboard in the device open position. Preferably, the display on the screen is rotated 90° between the open and closed positions, wherein the orientation is controlled by the position of the first panel or the position of the second panel. Preferably, the communication device keypad is locked in an inoperative mode in the device open position. In accordance with a second aspect of the invention, a function keyboard for use in a mobile communications device having a main body element, a communications keypad, and a screen for displaying information to the user is provided. A first panel having first and second faces is mounted on the main body element and has upper and lower surfaces for pivotal motion thereon between open and closed positions. The communications keypad is constructed on the first panel and is exposed for operative use in the device closed position. A second panel having a third face is mounted on the main body element for sideways rectilinear motion thereon and relative thereto between the device open and closed positions. The third face is accessible to the user in the device open position and inaccessible to the user in the device closed position; The function keyboard is constructed in two portions wherein a first portion is constructed in the second face of the first panel and a second portion is constructed in the third face of the second panel. Each of the function keyboard portions has an array of keys consistent with a selected function wherein the function keyboard is exposed for operative use in the device open position and the first and second panels are in overlapping alignment with one another in the device closed position. The first and second panels are in non-overlapping alignment with one another in the device open position and are located on opposite sides of the screen wherein an additional portion of the upper face of the main body element located beneath and substantially covered by the second panel in the device closed position is revealed and accessible to the user in the device open position. In accordance with a third aspect of the invention, a mobile communications device for operation in multiple applications is presented and comprises a main body element having upper and lower faces relative to usage and a screen constructed in at least a first portion of the upper face of the main body element to provide a visible display of information to the user. A first panel having first and second faces is mounted on the main body element for pivotal motion thereon between the device open and closed positions. The first face is accessible to the user in the device closed position and the second face is accessible to the user in the device open position. A second panel having a third face is mounted on the main body element for sideways rectilinear motion thereon and relative thereto between the device open and closed positions. The ,third face is accessible to the user in the device open position and inaccessible to the user in the device closed position wherein the first and second panels are in overlapping alignment with one another in the closed position. A communication keypad is constructed on the first face of the first panel and is exposed for operative use in the device closed position. A function keyboard is constructed in two portions, the first portion constructed in the second face of the first panel and a second portion constructed in the third face of the second panel, each of the function keyboard portions has an array of keys consistent with a selected function. The function keyboard is exposed for operative use in the device open position. The first and second panels are in non-overlapping alignment with one another in the device open position and are located on opposite sides of the screen wherein an additional portion of the upper face of the main body element located beneath and substantially covered by the second panel in the device closed position is revealed and accessible to the user in the device open position. In accordance with a fourth aspect of the invention, a function keyboard for use in an electronic device having a main body element, and a screen for displaying information to the user is presented wherein the keyboard includes a first panel having first and second faces mounted on the main body element having upper and lower surfaces for pivotal motion thereon between open and closed positions and a second panel having a third face mounted on the main body element for sideways rectilinear motion thereon and relative thereto between the device open and closed positions wherein the third face is accessible to the user in the device open position and inaccessible to the user in the device closed position. The function keyboard is constructed in two portions wherein a first portion is constructed in the second face of the first panel and a second portion is constructed in the third face of the second panel. Each of the function keyboard portions has an array of keys consistent with a selected function wherein said function keyboard is exposed for operative use in the device open position. The first and second panels are in overlapping alignment with one another in the device closed position and in non-overlapping alignment with one another in the device open position and the first and second panels are located on opposite sides of the screen in the device open position wherein an additional portion of the upper face of the main body element located beneath and substantially covered by the second panel in the device closed position is revealed and accessible to the user in the device open position. Preferably, the screen is constructed in the first portion and the additional portion of the upper face and defines a full screen wherein the first and second panels are in overlapping alignment with one another and the portion of the screen located in the additional portion of the upper face whereby the visible area for display of information is restricted to less than the full screen in the device closed position and wherein the full screen area is available for visible display of information to the user in the device open position. In accordance with a fifth aspect of the invention, an electronic device for operation in multiple applications is presented and includes a main body element having upper and lower faces relative to usage and a screen constructed in at least a first portion of the upper face of the main body element to provide a visible display of information to the user. A first panel having first and second face is mounted on the main body element for pivotal motion thereon between the device open and closed positions. The first face is accessible to the user in the device closed position and the second face is accessible to the user in the device open position. A second panel having a third face is mounted on the main body element for sideways rectilinear motion thereon and relative thereto between the device open and closed positions. The third face is accessible to the user in the device open position and inaccessible to the user in the device closed position and the first and second panels are in overlapping alignment with one another in the closed position. A function keyboard is constructed in two portions wherein a first portion is constructed in the second face of the first panel and a second portion constructed in the third face of the second panel. Each of the function keyboard portions has an array of keys consistent with a selected function. The function keyboard is exposed for operative use in the device open position wherein the function keyboard comprises a game controller with multiple function keys divided between the first and second panels. In accordance with a sixth aspect of the invention, an electronic device for operation in multiple applications includes a main body element having upper and lower faces relative to usage and a screen constructed in at least a first portion of the upper face of the main body element to provide a visible display of information to the user. A first panel having first and second faces is mounted on the main body element for pivotal motion thereon between the device open and closed positions. The first face is accessible to the user in the closed position and the second face is accessible to the user in the open position. A second panel having a third face is mounted on the main body element for sideways rectilinear motion thereon and relative thereto between open and closed positions. The third face is accessible to the user in the open position and inaccessible to the user in the closed position and the first and second panels are in overlapping alignment with one another in the closed position. A function keyboard is constructed in two portions wherein a first portion is constructed in the second face of the first panel and a second portion is constructed in the third face of the second panel. Each of the function keyboard portions has an array of keys consistent with a selected function, and is exposed for operative use in the device open position wherein the array of keys on the faces of the panels are offset to prevent interference between the keys of the faces in the device closed position. In accordance with a further aspect of the invention, an electronic device for operation in multiple applications is presented and includes a main body element having upper and lower faces relative to usage and a screen constructed in at least a first portion of the upper face of the main body element to provide a visible display of information to the user. A first panel having first and second faces is mounted on the main body element for pivotal motion thereon between open and closed positions. The first face is accessible to the user in the device closed position and the second face is accessible to the user in the device open position. A second panel having a third face is mounted on the main body element for sideways rectilinear motion thereon and relative thereto between the device open and closed positions. The third face is accessible to the user in the open position and inaccessible to the user in the closed position wherein the first and second panels are in overlapping alignment with one another in the closed position. A function keyboard is constructed in two portions wherein a first portion is constructed in the second face of the first panel and a second portion is constructed in the third face of the second panel. Each of the function keyboard portions has an array of keys consistent with a selected function wherein the function keyboard is exposed for operative use in the device open position and wherein the device is a mobile communication device and further comprises a communication keypad constructed on the first face of the first panel and is exposed for operative use in the closed position. The mobile communications device further includes a control unit that operates to rotate the orientation of the display on the screen consistent with the functional position of the first and second panels so that the display is aligned with the communication keypad in the device closed position and aligned with the functional keyboard in the device open position. In a yet further aspect of the invention, a function keyboard for use in an electronic device having a main body element, and a screen for displaying information to the user is presented wherein the keyboard includes a first panel having first and second faces mounted on the main body element having upper and lower surfaces for pivotal motion thereon between open and closed positions. A second panel having a third face is mounted on the main body element for sideways rectilinear motion thereon and relative thereto between open and closed positions. The third face is accessible to the user in the open position and inaccessible to the user in the closed position. The function keyboard is constructed in two portions wherein a first portion is constructed in the second face of the first panel and a second portion is constructed in the third face of the second panel. Each of the function keyboard portions has an array of keys consistent with a selected function and is exposed for operative use in the open position, and wherein the portions of the function keyboard include a game controller with multiple function keys divided between the first and second panels. | 20040114 | 20060829 | 20050714 | 97582.0 | 0 | ZEWARI, SAYED T | FOLDABLE/SLIDABLE FUNCTION KEYBOARD FOR AN ELECTRONIC DEVICE | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,758,317 | ACCEPTED | High temperature hydrogen annealing of a gate insulator layer to increase etching selectivity between conductive gate structure and gate insulator layer | A method of defining a conductive gate structure for a MOSFET device wherein the etch rate selectivity of the conductive gate material to an underlying insulator layer is optimized, has been developed. After formation of a nitrided silicon dioxide layer, to be used as for the MOSFET gate insulator layer, a high temperature hydrogen anneal procedure is performed. The high temperature anneal procedure replaces nitrogen components in a top portion of the nitrided silicon dioxide gate insulator layer with hydrogen components. The etch rate of the hydrogen annealed layer in specific dry etch ambients is now decreased when compared to the non-hydrogen annealed nitrided silicon dioxide counterpart. Thus the etch rate selectivity of conductive gate material to underlying gate insulator material is increased when employing the slower etching hydrogen annealed nitrided silicon dioxide layer. | 1. A method of forming a metal oxide semiconductor field effect transistor (MOSFET) on a semiconductor substrate, comprising the steps of: forming a gate insulator layer on said semiconductor substrate; performing a procedure to form a nitrided gate insulator layer; performing an anneal procedure; forming a conductive gate structure on a portion of said nitrided gate insulator layer; forming a lightly doped source/drain region in an area of said semiconductor substrate not covered by said conductive gate structure; forming insulator spacers on sides of said conductive gate structure; and forming a heavily doped source/drain region in an area of said semiconductor substrate not covered by said conductive gate structure or by said insulator spacers. 2. The method of claim 1, wherein said gate insulator layer is a silicon dioxide layer, obtained via a thermal oxidation procedure at a thickness between about 10 to 30 Angstroms. 3. The method of claim 1, wherein said nitrided gate insulator layer is a nitrided silicon dioxide layer, at an equivalent oxide thickness between about 7 to 20 Angstroms. 4. The method of claim 1, wherein said nitrided gate insulator layer is comprised with a dielectric constant between about 3.9 to 7.8. 5. The method of claim 1, wherein said procedure used to form said nitrided gate insulator layer is a plasma nitridation procedure, performed at a power between about 10 to 5000 watts, for a time that is sufficient to obtain a desired nitrogen content in a top portion of said gate insulator layer, with the plasma nitridation procedure performed in ambient comprised of N2 and helium, or of N2 and argon. 6. The method of claim 1, wherein said procedure used to form said nitrided gate insulator layer is an anneal procedure performed at a temperature between about 600 to 1100° C., for a time sufficient to obtain a desired nitrogen constant in said gate insulator layer, performed in ambient comprised of either NH3, NO, or N2O. 7. The method of claim 1, wherein said anneal procedure is performed to said nitrided gate insulator layer in a single wafer rapid thermal annealing (RTP), or in a batch type furnace system, performed in a hydrogen ambient at a temperature between about 800 to 1100° C., for a time between about 0.5 to 10 min. 8. The method of claim 1, wherein said anneal procedure is performed in situ, in the same tool to be used for deposition of a conductive gate material, with the anneal performed at a temperature between about 600 to 800° C., for a time between about 30 to 150 sec., using a hydrogen/nitrogen ratio that features a hydrogen percentage between about 10-50. 9. A method of forming a MOSFET device on a semiconductor substrate comprising the steps of: forming a silicon dioxide insulator layer on said semiconductor substrate; performing a procedure to form a nitrided silicon dioxide layer; performing a hydrogen anneal procedure; forming a polysilicon gate structure on said hydrogen annealed nitrided silicon dioxide layer; forming a lightly doped source/drain region in an area of said semiconductor substrate not covered by said polysilicon gate structure; forming insulator spacers on sides of said polysilicon gate structure; and forming a heavily doped source/drain region in an area of said semiconductor substrate not covered by said polysilicon gate structure or by said insulator spacers. 10. The method of claim 9, wherein said silicon dioxide layer is obtained via a thermal oxidation procedure, to a thickness between about 10 to 30 Angstroms. 11. The method of claim 9, wherein said procedure used to form said nitrided silicon dioxide layer is a plasma nitridation procedure, performed at a power between about 10 to 5000 watts, for a time that is sufficient to obtain a desired nitrogen content in a top portion of said silicon dioxide gate insulator layer, with the plasma nitridation procedure performed in ambient comprised of N2 and helium, or comprised of N2 and argon. 12. The method of claim 9, wherein said procedure used to form said nitrided silicon dioxide layer is an anneal procedure performed at a temperature between about 600 to 1100° C., for a time sufficient to obtain a desired nitrogen content in said silicon dioxide gate insulator layer, wherein said anneal procedure is performed in ambient comprised of either NH3, NO, or N2O. 13. The method of claim 9, wherein said nitrided silicon dioxide layer is comprised with an equivalent oxide thickness between about 7 to 20 Angstroms. 14. The method of claim 9, wherein said nitrided silicon dioxide layer is comprised with a dielectric constant between about 3.9 to 7.8. 15. The method of claim 9, wherein said hydrogen anneal procedure is performed in a single wafer rapid thermal annealing (RTP), or in a batch type furnace system, performed in a hydrogen ambient at a temperature between about 800 to 1100° C., for a time between about 0.5 to 10 min. 16. The method of claim 9, wherein said hydrogen anneal procedure is performed in situ in the same tool to be used for deposition of a polysilicon gate material, with said hydrogen anneal procedure performed at a temperature between about 600 to 800° C., for a time between about 30 to 150 sec., using a hydrogen/nitrogen ratio that features a hydrogen percentage between about 10-50. 17. A method of forming a metal oxide semiconductor field effect transistor (MOSFET) on a semiconductor substrate, comprising the steps of: forming a silicon dioxide gate insulator layer on said semiconductor substrate; performing an anneal procedure; forming a polysilicon gate structure on a portion of said silicon dioxide gate insulator layer; forming a lightly doped source/drain region in an area of said semiconductor substrate not covered by said polysilicon gate structure; forming insulator spacers on sides of said polysilicon gate structure; and forming a heavily doped source/drain region in an area of said semiconductor substrate not covered by said polysilicon gate structure or by said insulator spacers. 18. The method of claim 17, wherein said silicon dioxide gate insulator layer is obtained via a thermal oxidation procedure at a thickness between about 10 to 30 Angstroms. 19. The method of claim 17, wherein said anneal procedure is performed in a single wafer rapid thermal annealing (RTP), or in a batch type furnace system, performed in a hydrogen ambient at a temperature between about 800 to 1100° C., for a time between about 0.5 to 10 min. 20. The method of claim 17, wherein said anneal procedure is performed in situ, in the same tool to be used for deposition of a polysilicon gate material, with the anneal performed at a temperature between about 600 to 800° C., for a time between about 30 to 150 sec., using a hydrogen/nitrogen that features a hydrogen percentage between about 10-50. | BACKGROUND OF THE INVENTION (1) Field of the Invention The present method relates to methods used to fabricate semiconductor devices, and more specifically to a method used to increase the etch rate selectivity of a dry etch procedure employed for the definition of a conductive gate structure. (2) Description of Prior Art Micro-miniaturization, or the ability to fabricate semiconductor devices with sub-micron features, has allowed performance increases for the sub-micron MOSFET devices to be realized, basically via reductions in performance degrading junction capacitances. Sub-micron MOSFET devices are also being fabricating featuring thin silicon dioxide gate insulator layers, used to allow operating voltages to be decreased. The use of thinner silicon dioxide layers however can present higher leakage currents than counterparts comprised with thicker silicon dioxide gate insulator layers. Formation of nitrided gate insulator layers such as a nitrided silicon dioxide layer, can however reduce leakage in thin gate insulator layers. The higher dielectric constant of the nitrided gate insulator layer when compared to non-nitrided silicon dioxide gate insulator counterparts, as well as maintaining an equivalent oxide thickness (EOT), result in lower leakage currents thus making nitrided silicon dioxide gate insulator layer an attractive option for sub-micron MOSFET devices. The employment of nitrided gate insulator layer can however present difficulties during definition of an overlying conductive gate structure. Selective dry etch procedures employed for gate structure definition are designed to terminate at the exposure of the gate insulator layer in areas not covered by the now defined gate structure, at dry etch end point. This is accomplished via a high etch rate ratio between the conductive gate structure material, such as polysilicon, and the underlying gate insulator material, such as silicon dioxide. However the presence of the underlying nitrided silicon dioxide layer, featuring an undesirable faster etch rate than non-nitrided silicon dioxide, results in a decreased etch rate ratio. The lower etch rate selectivity resulting form the presence of nitrided silicon dioxide underlays adds complexity and difficulty to end point control for the conductive gate structure, selective dry etch definition procedure, sometimes resulting in break through of the nitrided silicon dioxide layer and unwanted pitting or damage of underlying semiconductor substrate regions. The damaged semiconductor regions, subsequently used to accommodate MOSFET features such as source/drain regions, can result in decreased MOSFET yield, performance and reliability. The present invention will describe a procedure in which nitrided gate insulator layers can be employed as a component of a sub-micron MOSFET device, while still allowing the high etch rate ratio of conductive gate material to nitrided gate insulator material to be maintained. This is accomplished via a simple process step performed to the nitrided gate insulator material prior to deposition of the material used for the conductive gate structure. Prior art such as Miyazaki, in U.S. Pat. No. 6,335,278 B1, as well as Houston et al, in U.S. Pat. No. 6,569,741 B2, have described annealing procedures employed to remedy device leakage problems. However none of the above prior art offer the process described in this present invention in which a nitrided gate insulator layer is treated prior to deposition of a conductive gate material to maintain a high etch rate ratio for a subsequent dry etch procedure employed for the definition of a conductive gate structure. SUMMARY OF THE INVENTION It is an object of this invention to fabricate a MOSFET device featuring an ultra-thin, less than 20 Angstroms, gate insulator layer. It is another object of this invention to employ a nitrided silicon dioxide layer as a gate insulator for a MOSFET device. It is still another object of this invention to perform a high temperature hydrogen anneal procedure prior to deposition of the conductive gate material to increase the etch rate ratio of the conductive gate material to the nitrided gate material for a conductive gate definition procedure. In accordance with the present invention a method of increasing the etch selectivity between a conductive gate material and an underlying nitrided gate insulator material during a conductive gate dry etch definition procedure, via a hydrogen anneal procedure performed prior to deposition of the conductive gate layer, is described. After formation of a silicon dioxide gate insulator layer on a semiconductor substrate, a nitrogen treatment is performed resulting in a nitrided gate insulator layer. An anneal procedure, accomplished in a hydrogen containing ambient at a temperature between about 800 to 1100° C., is next performed on the underlying nitrided silicon dioxide gate insulator layer. After formation of a doped polysilicon layer, and of an overlying photoresist shape, a dry etch procedure is employed to define a polysilicon gate structure on an underlying hydrogen annealed, nitrided silicon dioxide gate insulator layer with the dry etch procedure selectively terminating at the appearance of portions of the hydrogen annealed nitrided silicon dioxide layer not covered by the defined polysilicon gate structure. An additional embodiment of this invention is the hydrogen annealing of a thin silicon dioxide gate insulator layer, again performed to improve the etch selectivity between the conductive gate material and the underlying, hydrogen annealed silicon dioxide layer, during the conductive gate structure definition procedure. BRIEF DESCRIPTION OF THE DRAWINGS The object and other advantages of this invention are best described in the preferred embodiments with reference to the attached drawings that include: FIGS. 1-7, which schematically, in cross-sectional style, describe key stages used to fabricate a MOSFET device featuring a high temperature hydrogen anneal procedure performed on a nitrided gate insulator layer prior to deposition of a conductive gate structure material to increase the etch rate ratio of the conductive gate material to an underlying nitrided gate insulator material during a subsequent conductive gate structure dry etch definition procedure. DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of defining a MOSFET conductive gate structure on an underlying nitrided gate insulator layer, wherein the etch rate ratio of the conductive gate material to the underlying nitrided gate insulator material is increased via a high temperature hydrogen anneal procedure performed to the nitrided gate insulator layer prior to deposition of the conductive gate material, will now be described in detail. Semiconductor substrate 1, comprised of P type single crystalline silicon, featuring a <100> crystallographic orientation, is used and schematically shown in FIG. 1. Thermal oxidation procedures are next employed at a temperature between about 700 to 1100° C., in an oxygen or steam ambient, resulting in the growth of silicon dioxide gate insulator layer 2a, at a thickness between about 10 to 30 Angstroms, and featuring a dielectric constant between about 3.8 to 4.0. This is schematically shown in FIG. 1. The integrity of thin silicon dioxide layers needed for sub-micron MOSFET applications, can however be less in terms of leakage current when compared to thicker gate insulator counterparts. One method of improving gate insulator integrity while still maintaining an equivalent oxide thickness, is the formation of nitrided silicon dioxide layers via nitridization of top portions of thin silicon dioxide layers. Methods such as plasma nitridation or annealing performed in nitrogen containing ambient 3, can be used to form a nitrided silicon dioxide layer. For this description silicon dioxide layer 2a, is subjected to a plasma nitridation procedure performed in a plasma tool at a power between 10 to 5,000 watts, for a time that is sufficient to obtain a desired nitrogen content in ambient 3, wherein ambient 3, is comprised of either nitrogen and helium, or nitrogen and argon. Resulting nitrided silicon dioxide layer 2b, now comprised with a dielectric constant between about 3.9 to 7.8, with an equivalent oxide thickness between about 7 to 20 Angstroms, is schematically shown in FIG. 2. If desired nitrided silicon dioxide layer 2b, can be obtained via subjection of silicon dioxide layer 2a, to an anneal procedure performed at a temperature between about 600 to 1100° C., for a time that is sufficient to obtain the desired nitrogen content in ambient 3, in an ambient comprised of either NH3, NO, or N2O. The nitrided silicon dioxide layer is comprised with the highest concentration of nitrogen located at top surface of the layer. The presence of the high nitrogen concentration at the top surface of nitrided silicon dioxide layer 2b, can present difficulties during a subsequent dry etching procedure used for conductive gate structure definition. It is desirable for the conductive gate structure definition procedure to feature a high etch rate ratio for the conductive gate material in relation to the underlying gate insulator layer so that at end point, or after definition of the conductive gate structure, the dry etch procedure will slow or terminate at the appearance of the top surface of gate insulator layer. Without this desired etch rate selectivity portions of the semiconductor substrate, to be used for subsequent MOSFET device regions, can be vulnerable to the dry etch procedure. The presence of a nitrogen containing top surface for nitrided silicon dioxide layer 2b, however reduces the etch rate selectivity between conductive gate material and the underlying gate insulator layer when compared to counterparts in which the underlying gate insulator layer is comprised with only silicon dioxide or with nitrided silicon dioxide layers featuring lower nitrogen concentrations. Therefore a method of reducing nitrogen concentration at the top surface of nitrided silicon dioxide layer 2b, a method needed to increase the etch rate selectivity of a subsequent conductive gate structure dry etch procedure, has been developed. After formation nitrided silicon dioxide layer 2b, an anneal procedure is performed in hydrogen ambient 4, at a temperature between about 800 to 1100° C., for a time between about 0.5 to 10 min. The high temperature hydrogen anneal replaces nitrogen in a top portion of nitrided silicon dioxide layer 2b, with hydrogen, now resulting in hydrogen annealed nitrided silicon dioxide layer 2c. This is schematically shown in FIG. 3. The high temperature hydrogen anneal procedure has to be performed prior to deposition of a conductive gate material, and a first embodiment of this invention entails the anneal procedure performed in single wafer rapid thermal annealing (RTP) system or a batch type furnace system, either performed at the above conditions, that is 800 to 1100° C., for a time between about 0.5 to 10 min. If desired a second embodiment of this invention entails the high temperature hydrogen anneal procedure being performed in situ in the same tool to be used for deposition of polysilicon, with the anneal performed prior to polysilicon deposition, at a temperature between about 600 to 800° C., for a time between about 30 to 150 sec., using a hydrogen/nitrogen ratio that features a hydrogen percentage between about 10-50. Deposition of conductive layer 5a, a layer comprised of a material such as a doped polysilicon, is next addressed and schematically shown in FIG. 4. Doped polysilicon layer 5a, is deposited at a thickness between about 500 to 2000 Angstroms via a low pressure chemical vapor deposition (LPCVD) procedure. Doping of the polysilicon layer can be accomplished in situ during deposition via the addition of arsine or phosphine to a silane, or to a disilane ambient, or the polysilicon layer can be deposited intrinsically then doped via implantation of arsenic or phosphorous ions. If desired a metal silicide layer such as tungsten silicide, or a metal layer such as tungsten, can be used as the conductive layer, however the critical sequence is the high temperature hydrogen anneal performed prior to deposition of the conductive layer. Definition of a conductive gate structure, via a selective dry etch procedure, is next addressed and schematically described using FIG. 5. Photoresist shape 6, with a width between about 400 to 12,000 Angstroms is formed on conductive layer 5b, then used as an etch mask to allowing conductive gate structure 5b, to be defined. The dry etch procedure is an anisotropic reactive ion etch (RIE) procedure, employing Cl2 or CF4 as a selective etchant for conductive layer, or for doped polysilicon layer 5a. The RIE procedure is selective in that the end point for the definition of polysilicon gate structure 5b, is accomplished when the RIE procedure slows or terminates at the appearance of hydrogen annealed, nitrided silicon dioxide layer 2c. The etch rate ratio of doped polysilicon to the hydrogen annealed, nitrided silicon dioxide layer, is between about 200 to 1, to 400 to 1. This high etch rate ratio allowed termination of the conductive gate structure definition procedure to terminate at the surface, or in a top portion of hydrogen annealed, nitrided silicon dioxide layer 2c. Without the conversion of a top portion of the nitrided silicon dioxide layer to a layer comprised with hydrogen termination of the conductive gate structure definition procedure would be difficult, possibly resulting in damage or pitting of the portions of semiconductor substrate not overlaid by the conductive gate structure, and possibly resulting in unwanted decreases in MOSFET device performance and yield. After definiton of conductive, or polysilicon gate structure 5b, photoresist shape 6, is removed via plasma oxygen ashing procedures. The desired high etch rate selectivity between a conductive gate material and an underlying gate insulator layer obtained via high temperature annealing of the gate insulator layer prior to deposition of the conductive gate material, can also be applied to non-nitrided silicon dioxide gate insulator layers. Again the anneal procedure can either be performed in a rapid thermal annealing or batch type furnace system, or the anneal procedure can be performed in situ in the same tool to be subsequently used for polysilicon deposition. The hydrogen anneal conditions used for the non-nitrided, silicon dioxide gate insulator layer are identical to the anneal conditions detailed in the previous embodiments featuring nitrided silicon dioxide layers. The hydrogen annealing of a non-nitrided silicon dioxide layer results in improved etch rate selectivity between polysilicon and hydrogen annealed silicon dioxide when compared to the etch rate selectivity between polysilicon and non-hydrogen annealed silicon dioxide. Formation of lightly doped source/drain (LDD) region 7, is next addressed in a region of semiconductor substrate 1, not covered by conductive gate structure 5b, via implantation of arsenic or phoshorous ions, implanted at an energy between about 1 to 10 KeV, at a dose between about 1 E14 to 1 E16 atoms/cm2. If damaged had occurred to the portion of semiconductor substrate 1, accommodating LDD region 7, MOSFET leakage phenomena may have resulted. However the presence of hydrogen annealed, nitrided silicon dioxide layer 2c, protected this semiconductor region during conductive gate structure definition procedure thus preventing damage or pitting of this semiconductor region. The result of this procedure is schematically shown in FIG. 6. The completion of the MOSFET device comprised with a hydrogen annealed, nitrided silicon dioxide gate insulator layer will now be addressed and schematically shown in FIG. 7. An insulator layer such as silicon oxide or silicon nitride is deposited at a thickness between about 400 to 700 Angstroms, via LPCVD or via plasma enhanced chemical vapor deposition (PECVD) procedures. An anisotropic RIE procedure using CHF4 or CF4 as an etchant for the insulator layer is used to define insulator spacers 8, located on the sides of conductive gate structure 5b. In addition the insulator spacer defining anisotropic RIE procedure selectively removes the portions of hydrogen annealed, silicon dioxide layer 2c, not covered by either conductive gate structure 5b, or by insulator spacers 8. The anisotropic RIE procedure, using the above etchants, selectively terminates at the appearance of semiconductor substrate 1. Heavily doped source/drain region 9, is next formed via implantation of arsenic or phosphorous ions in exposed portions of semiconductor substrate 1, using an implant energy between about 5 to 30 KeV, and a dose between about 1 E14 to 1 E16 atoms/cm2. An anneal procedure can now be employed to activate the implanted species in LDD region 7, and in heavily doped source/drain region 9. Although this invention was described for an N channel MOSFET device, it should be understood that the hydrogen annealed, nitrided silicon dioxide gate insulator layer can be applied to P channel MOSFET device, or to CMOS devices comprised with both N channel and P channel MOSFET devices. While this invention has been particularly shown and described with reference to, the preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of this invention. | <SOH> BACKGROUND OF THE INVENTION <EOH>(1) Field of the Invention The present method relates to methods used to fabricate semiconductor devices, and more specifically to a method used to increase the etch rate selectivity of a dry etch procedure employed for the definition of a conductive gate structure. (2) Description of Prior Art Micro-miniaturization, or the ability to fabricate semiconductor devices with sub-micron features, has allowed performance increases for the sub-micron MOSFET devices to be realized, basically via reductions in performance degrading junction capacitances. Sub-micron MOSFET devices are also being fabricating featuring thin silicon dioxide gate insulator layers, used to allow operating voltages to be decreased. The use of thinner silicon dioxide layers however can present higher leakage currents than counterparts comprised with thicker silicon dioxide gate insulator layers. Formation of nitrided gate insulator layers such as a nitrided silicon dioxide layer, can however reduce leakage in thin gate insulator layers. The higher dielectric constant of the nitrided gate insulator layer when compared to non-nitrided silicon dioxide gate insulator counterparts, as well as maintaining an equivalent oxide thickness (EOT), result in lower leakage currents thus making nitrided silicon dioxide gate insulator layer an attractive option for sub-micron MOSFET devices. The employment of nitrided gate insulator layer can however present difficulties during definition of an overlying conductive gate structure. Selective dry etch procedures employed for gate structure definition are designed to terminate at the exposure of the gate insulator layer in areas not covered by the now defined gate structure, at dry etch end point. This is accomplished via a high etch rate ratio between the conductive gate structure material, such as polysilicon, and the underlying gate insulator material, such as silicon dioxide. However the presence of the underlying nitrided silicon dioxide layer, featuring an undesirable faster etch rate than non-nitrided silicon dioxide, results in a decreased etch rate ratio. The lower etch rate selectivity resulting form the presence of nitrided silicon dioxide underlays adds complexity and difficulty to end point control for the conductive gate structure, selective dry etch definition procedure, sometimes resulting in break through of the nitrided silicon dioxide layer and unwanted pitting or damage of underlying semiconductor substrate regions. The damaged semiconductor regions, subsequently used to accommodate MOSFET features such as source/drain regions, can result in decreased MOSFET yield, performance and reliability. The present invention will describe a procedure in which nitrided gate insulator layers can be employed as a component of a sub-micron MOSFET device, while still allowing the high etch rate ratio of conductive gate material to nitrided gate insulator material to be maintained. This is accomplished via a simple process step performed to the nitrided gate insulator material prior to deposition of the material used for the conductive gate structure. Prior art such as Miyazaki, in U.S. Pat. No. 6,335,278 B1, as well as Houston et al, in U.S. Pat. No. 6,569,741 B2, have described annealing procedures employed to remedy device leakage problems. However none of the above prior art offer the process described in this present invention in which a nitrided gate insulator layer is treated prior to deposition of a conductive gate material to maintain a high etch rate ratio for a subsequent dry etch procedure employed for the definition of a conductive gate structure. | <SOH> SUMMARY OF THE INVENTION <EOH>It is an object of this invention to fabricate a MOSFET device featuring an ultra-thin, less than 20 Angstroms, gate insulator layer. It is another object of this invention to employ a nitrided silicon dioxide layer as a gate insulator for a MOSFET device. It is still another object of this invention to perform a high temperature hydrogen anneal procedure prior to deposition of the conductive gate material to increase the etch rate ratio of the conductive gate material to the nitrided gate material for a conductive gate definition procedure. In accordance with the present invention a method of increasing the etch selectivity between a conductive gate material and an underlying nitrided gate insulator material during a conductive gate dry etch definition procedure, via a hydrogen anneal procedure performed prior to deposition of the conductive gate layer, is described. After formation of a silicon dioxide gate insulator layer on a semiconductor substrate, a nitrogen treatment is performed resulting in a nitrided gate insulator layer. An anneal procedure, accomplished in a hydrogen containing ambient at a temperature between about 800 to 1100° C., is next performed on the underlying nitrided silicon dioxide gate insulator layer. After formation of a doped polysilicon layer, and of an overlying photoresist shape, a dry etch procedure is employed to define a polysilicon gate structure on an underlying hydrogen annealed, nitrided silicon dioxide gate insulator layer with the dry etch procedure selectively terminating at the appearance of portions of the hydrogen annealed nitrided silicon dioxide layer not covered by the defined polysilicon gate structure. An additional embodiment of this invention is the hydrogen annealing of a thin silicon dioxide gate insulator layer, again performed to improve the etch selectivity between the conductive gate material and the underlying, hydrogen annealed silicon dioxide layer, during the conductive gate structure definition procedure. | 20040115 | 20070123 | 20050721 | 71382.0 | 0 | DEO, DUY VU NGUYEN | HIGH TEMPERATURE HYDROGEN ANNEALING OF A GATE INSULATOR LAYER TO INCREASE ETCHING SELECTIVITY BETWEEN CONDUCTIVE GATE STRUCTURE AND GATE INSULATOR LAYER | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,758,401 | ACCEPTED | Amplification of DNA in a hairpin structure, and applications | The present invention is directed to a hairpin nucleic acid structure and its use. In a preferred embodiment, the hairpin nucleic acid structure can be used in a method of amplification of a template nucleic acid sequence that substantially reduces polymerase-induced errors. | 1. A method of converting a double stranded nucleic acid into a hairpin structure, wherein the double stranded nucleic acid contains at least one sequence of interest, and is referred to as the template nucleic acid, comprising either (1) ligating a first single stranded nucleic acid to a first end of the upper strand of the template nucleic acid, and ligating a second single stranded nucleic acid which is non-complementary to the first single stranded nucleic acid to the first end of the lower strand of the nucleic acid; or (2) ligating a cap of single stranded nucleic acid to both the upper strand and the lower strand of the first end of the template nucleic acid, wherein said cap contains a sequence about midway in the cap, and that cannot be amplified by polymerase chain reaction (PCR), and wherein the nucleic acid bases on either side of this sequence are not complementary to each other; and further comprising ligating a cap of single stranded nucleic acid to both the lower strand and the upper strand of the second end of the nucleic acid, such that the upper strand and the lower strand of the second end are contiguous, creating the final hairpin structure. 2. A method of amplifying the hairpin structure of claim 1, comprising performing polymerase chain reaction with a first primer that binds to at least a portion of the upper single stranded non-complementary region, and a second primer that binds to at least a portion of the lower single stranded non-complementary region. 3. The method of claim 1, wherein the upper single stranded non-complementary region and the lower single stranded non-complementary region are about 20-40 basepairs long. 4. The method of claim 1, wherein one strand of the template nucleic acid is joined with a second, fully complementary nucleic acid strand such that the two strands are contiguous, and such that during amplification the polymerase copies both the upper strand of the template nucleic acid and the lower strand of the template nucleic acid in a single pass. 5. The method of claim 4, wherein the upper strand of the template nucleic acid is joined with the fully complementary lower strand of the template nucleic acid, such that during amplification the polymerase copies both the upper strand and the lower strand in a single pass. 6. A method of amplifying a nucleic acid sequence of interest which generates a PCR-amplified product which is substantially free of polymerase-induced errors, comprising: (a) converting the sequence of interest into a hairpin DNA structure; (b) amplifying the hairpin DNA using PCR with a first primer that binds to at least a portion of the upper single stranded region, and a second primer that binds to at least a portion of the lower single stranded region; (c) converting the PCR products into hairpin structures by a method which induces denaturation followed by sudden renaturation; (d) identifying hairpins containing polymerase-generated nucleotide changes, insertions, and deletions, via the resulting mismatched bases comprising gaps in binding, and (e) removing such hairpin DNAs containing polymerase generated mismatched nucleotides, and collecting the DNA that contains no mismatches. 7. The method of claim 6, wherein the method which induces denaturation followed by sudden renaturation is selected from the group consisting of (a) heat denaturation followed by rapid cooling, (b) addition of sodium hydroxide followed by sudden neutralization of the solution, and (c) addition of formamide followed by sudden removal of formamide. 8. The method of claim 6, wherein the hairpin DNAs containing PCR-induced errors have a mismatch in the double stranded region and are separated from hairpin DNAs which do not contain PCR-induced errors by a method which recognizes DNA containing a mismatch. 9. The method of claim 8, wherein the method which recognizes DNA containing mismatches is selected from the group consisting of dHPLC-mediated fraction collection, denaturing gradient gel electrophoresis (DGGE), constant denaturant gel electrophoresis (CDGE), constant denaturant capillary electrophoresis (CDCE), and an enzymatic-based separation method. 10. The method of claim 9, wherein the enzymatic-based separation method is performed either in solution or bound to a solid support, and the enzyme is at least one enzyme selected from the group consisting of mismatch-recognition enzymes MutS, MutY, and TDG; Ce1 I; resolvases; endonuclease V; cleavases, and exonucleases. 11. The method of claim 6, wherein (a) during the course of amplification the polymerase-generated errors are converted to mismatches and remain as mismatches during each cycle of amplification, and (b) following the end of amplification all the polymerase-generated errors are in a mismatched structure while all the mutations are in a matched structure. 12. The method of claim 6, wherein one strand of the template nucleic acid is joined with a second, fully complementary nucleic acid strand such that the two strands are contiguous, and such that during amplification the polymerase copies both the upper strand of the template nucleic acid and the lower strand of the template nucleic acid in a single pass. 13. The method of claim 12, wherein the upper strand of the template nucleic acid is joined with the fully complementary lower strand of the template nucleic acid, such that during amplification the polymerase copies both the upper strand and the lower strand in a single pass. 14. A method of amplifying a nucleic acid sequence of interest which generates a PCR-amplified product which is substantially free of polymerase-induced errors, comprising: (a) converting the sequence of interest into a hairpin DNA structure; (b) amplifying the hairpin DNA using PCR with a first primer that binds to at least a portion of the upper single stranded region, and a second primer that binds to at least a portion of the lower single stranded region; wherein the concentration of primers are either equal to each other (‘regular PCR’) or unbalanced (‘asymmetric PCR’); (c) identifying hairpins containing polymerase-generated nucleotide changes, insertions, and deletions, via the resulting mismatched bases comprising gaps in binding; and (d) removing such hairpin DNAs containing polymerase generated mismatched nucleotides, and collecting the DNA that contains no mismatches. 15. A method of improving the fidelity of an assay that relies on a PCR-amplified nucleic acid template for at least one step of the assay, wherein the PCR-amplified nucleic acid template is generated using the method of claim 6. 16. The method of claim 15, wherein the assay is selected from the group consisting of mutation detection, mutation analysis, polymorphism detection, polymorphism analysis, microsatellite analysis, cloning, and protein functional analysis. 17. The method of claim 16, wherein the method of mutation or polymorphism detection is selected from the group consisting of PCR, PCR/RE/LCR, MutEx-ACB-PCR, RFLP analysis, and APRIL-ATM. 18. A method of detecting DNA damage in a nucleic acid sequence of interest, comprising: (a) converting the sequence of interest into a hairpin DNA structure; (b) amplifying the hairpin DNA using PCR with a first primer that binds to at a first portion of the upper single stranded region, and a second primer that binds to a second portion of the upper single stranded region; and (c) purifying the PCR products, wherein only those sequences of interest that contain damaged DNA are amplified. 19. A method of converting a double stranded nucleic acid into a hairpin structure, wherein the double stranded nucleic acid contains at least one sequence of interest, and is referred to as the template nucleic acid, comprising either: a) ligating a cap of single stranded nucleic acid to both the lower strand and the upper strand of both ends of the nucleic acid, such that the upper strand and the lower strand of the second end are contiguous, creating the final hairpin structure; or b) forming a hairpin by digesting the double stranded nucleic acid sequence with two restriction enzymes which generate different overhangs to generate a doubly digested nucleic acid with a first overhang at a first end of the nucleic acid and a second overhang at a second end of the nucleic acid; ligating a first doubly digested nucleic acid to a second, identical, doubly digested nucleic acid such that the first overhang of the first sequence ligates to the first overhang of the second sequence; and second overhang of the first sequence ligates to the second overhang of the second sequence, creating the final hairpin structure. 20. A method of amplifying a nucleic acid sequence of interest which generates an amplified product which is substantially free of polymerase-induced errors, comprising: a) converting the sequence of interest into a hairpin structure; b) amplifying the hairpin structure using a polymerase and primers to perform rolling circle amplification of the hairpin structure such that both the upper strand and the lower strand are continuously amplified in succession each time the polymerase performs a full circle around the hairpin structure, generating an amplification product comprising repeated single stranded units of the sequence of interest; c) cleaving the amplification product with a restriction enzyme to generate individual amplified nucleic acid molecules comprising a single copy of the sequence of interest each; d) converting the amplified nucleic acid molecules into hairpin structures by a method which induces denaturation followed by sudden renaturation; e) identifying hairpins containing polymerase-generated nucleotide changes, insertions, and deletions, via the resulting mismatched bases comprising gaps in binding; and f) removing such hairpin DNAs containing polymerase generated mismatched nucleotides, and collecting the DNA that contains no mismatches. 21. The method of claim 20, wherein the polymerase is Phi29. 22. The method of claim 20, wherein the primers are random hexamers. 23. The method of claim 20, wherein the method which induces denaturation followed by sudden renaturation is selected from the group consisting of (a) heat denaturation followed by rapid cooling, (b) addition of sodium hydroxide followed by sudden neutralization of the solution, and (c) addition of formamide followed by sudden removal of formamide. 24. The method of claim 20, wherein the hairpin DNAs containing polymerase-induced errors have a mismatch in the double stranded region and are separated from hairpin DNAs which do not contain polymerase-induced errors by a method which recognizes DNA containing a mismatch. 25. The method of claim 24, wherein the method which recognizes DNA containing mismatches is selected from the group consisting of dHPLC-mediated fraction collection, denaturing gradient gel electrophoresis (DGGE), constant denaturant gel electrophoresis (CDGE), constant denaturant capillary electrophoresis (CDCE), and an enzymatic-based separation method. 26. The method of claim 25, wherein the enzymatic-based separation method is performed either in solution or bound to a solid support, and the enzyme is at least one enzyme selected from the group consisting of mismatch-recognition enzymes MutS, MutY, and TDG; Ce1 I; resolvases; endonuclease V; cleavases, and exonucleases. 27. A method of improving the fidelity of an assay that relies on a PCR-amplified nucleic acid template for at least one step of the assay, wherein the PCR-amplified nucleic acid template is generated using the method of claim 20. 28. The method of claim 27, wherein the assay is selected from the group consisting of mutation detection, mutation analysis, polymorphism detection, polymorphism analysis, microsatellite analysis, cloning, and protein functional analysis. 29. The method of claim 28, wherein the method of mutation or polymorphism detection is selected from the group consisting of PCR, PCR/RE/LCR, MutEx-ACB-PCR, RFLP analysis, and APRIL-ATM. 30. A nucleic acid useful for amplifying a double stranded nucleic acid sequence of interest to generate an amplified product which is substantially free of polymerase-induced errors, comprising a priming structure ligated to a first end of a double stranded nucleic acid of interest, wherein the priming structure is either an oligonucleotide cap comprising a single stranded oligonucleotide that forms a hairpin structure of at least 10 nucleotides, or the priming structure comprises a pair of oligonucleotides which are complementary to each other at the ends ligated to the nucleic acid sequence of interest, and non-complementary to each. other at the ends which are not ligated to the nucleic acid sequence of interest. 31. The nucleic acid of claim 30, wherein the priming structure is an oligonucleotide cap which further comprises a polymerase block at the approximate midpoint of the priming structure, wherein said polymerase block prevents polymerization by a polymerase. 32. The nucleic acid of claim 31, wherein said polymerase block is selected from the group consisting of one or more abasic nucleotides, a deoxynucleotide analogue that does not allow polymerase synthesis; and uracil. 33. The nucleic acid of claim 32, wherein the polymerase block is uracil and, following ligation to the double stranded nucleic acid sequence of interest and amplification, the cap is treated with uracil glycosylase and heat to generate a strand break. 34. A nucleic acid useful for amplifying a double stranded nucleic acid sequence of interest to generate an amplified product which is substantially free of polymerase-induced errors, comprising the nucleic acid of claim 30 ligated at a second end to a joining structure, wherein said joining structure comprises an oligonucleotide cap, wherein said oligonucleotide cap comprises a single stranded oligonucleotide that forms a hairpin structure of at least 10 nucleotides and does not contain a polymerase block. | CROSS-REFERENCE TO RELATED APPLICATIONS This application claims benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application No. 60/440,184, filed Jan. 15, 2003, which is incorporated herein by reference. FIELD OF THE INVENTION The present invention is directed to a hairpin nucleic acid structures and its use. In a preferred embodiment, the hairpin nucleic acid structure can be used in a method of amplification of a template nucleic acid sequence that substantially reduces polymerase-induced errors. BACKGROUND OF THE INVENTION Substantial interest has been directed to the detection of changes in nucleic acid sequences, such as caused by mutation and methylation. For example, mutation in certain genes have been associated with a variety of disorders-ranging from blood disorders to cancers. Genetic testing is one way to find this information out. However, our ability to detect such mutations is limited by certain problems with a key component in these tests, namely the polymerase chain reaction (PCR). A major problem with PCR is that polymerases invariably generate errors during amplification. Such polymerase misincorporations can be indistinguishable from genuine mutations, and lower the quality of DNA cloning and protein functional analysis by in vitro translation. Polymerase misincorporations set a limit for molecular mutation detection methods: the most selective technologies invariably rely on PCR, but PCR also poses a final selectivity limit, typically 1 mutant in 105-106 alleles, since all DNA polymerases generate errors during DNA synthesis which can be misinterpreted as mutations (false positives). Thus, high selectivity mutation detection technologies often fall short of the enormous selectivity needed to address issues like the generation of spontaneous mutations in somatic tissues 1,2, the early detection of genomic instability 3, the mutation screening of single cells 4 or the reliable detection of minimal residual disease 5, 6. Both unknown and known mutation detection methods are affected by PCR errors and the most selective methods are affected most. For example, the principal limitation for mutation scanning via constant denaturant capillary electrophoresis (CDCE) is the fidelity of the polymerase used 7, 8. High selectivity mutation scanning via DGGE and dHPLC is ultimately hindered by polymerase error rate 7, 9, 10. Some of the highest sensitivity assays for RFLP-based known mutation detection, including PCR/RE/LCR 11, MutEx-ACB-PCR 12, Radioactivity-based PCR-RFLP 13, RSM 14, 15, APRIL-ATM 16, and others reviewed in Parsons et al. 17, utilize PCR in at least one stage prior to RFLP-selection, and are therefore also limited by PCR errors 18. Accordingly, it would be desirable if one had a means of amplifying DNA free of polymerase-induced misincorporations, to detect mutations without being limited by polymerase-induced errors. This could significantly impact mutation detection, disease diagnosis, and cancer diagnosis. SUMMARY OF THE INVENTION We have now discovered compositions and methods to amplify a target nucleic acid sequence, sometimes referred to as the template, that substantially reduces polymerase induced errors in a sequence of interest, and which can supply existing technologies with the necessary ‘selectivity leap’. The first step of this method involves converting the sequence of interest into a hairpin, which contains a double stranded region linked at one end through a single stranded loop, and performing PCR on the hairpin-structure. In the second step, the amplified PCR products are heat denatured and rapidly cooled, to convert each amplified PCR product into a hairpin: genuine polymorphisms or mutations will remain fully matched in the hairpin, whereas PCR products which contain a PCR induced error will form a hairpin that contains a mismatch in the double-stranded region. Thereafter, one removes those amplified nucleic acids which contain a mismatch by standard means. This method results in an amplified target nucleic acid which is substantially free of polymerase induced errors. In an alternative embodiment, amplification of the hairpin structure is performed using isothermal rolling circle amplification (RCA). True nucleic acid changes such as from a mutation can be separated from polymerase-generated single nucleotide changes, insertions, deletions, or slippage thereby providing practically error-less nucleic acid, preferably DNA. By using a hairpin sequence one can obtain a sample (template) from a range of sources such as from genomic DNA. Large fractions of the human genome can be amplified via hairpin PCR to provide faithfully—replicated genomic DNA for extensive, genome-wide screening for differences from a standard. This is particularly desirable when starting from limited amounts of biopsy material, i.e. from a few cells obtained via laser capture microdissection. Additional technical factors limit the overall selectivity of mutation detection (e.g. amount of DNA; mis-priming; heteroduplex formation; incomplete enzymatic digestion 15); however, with appropriate selection of conditions these problems can often be overcome. In contrast, PCR errors have been regarded as a ‘glass ceiling’ for mutation detection selectivity. The present method of using hairpin PCR will allow a boost to almost every existing method for highly selective mutation detection and lead to studies and diagnostic tests that were impossible with previous technology by substantially reducing the number of errors that are an artifact of PCR from the sample. This method will also improve microsatellite analysis by eliminating polymerase ‘slippage’ artifacts 19 and will also have application in other areas such as molecular beacons 20,21 and real time PCR, DNA cloning 22 or protein functional analysis by in vitro translation 4. In one embodiment of the present invention, a hairpin with non-complementary ends can be efficiently PCR-amplified. In this embodiment, a target DNA sequence which needs to be PCR-amplified is first converted to a hairpin following ligation of an oligonucleotide ‘cap’ on one end and a pair of non-complementary linkers on the other end (See FIG. 1A). Next, primers corresponding to the two non-complementary linkers are used in a PCR reaction that proceeds by displacing the opposite strand and amplifying the entire complement of the hairpin. In one preferred embodiment, these primers corresponding to the non-complementary linkers can overlap the sequence of interest, thus conferring sequence specificity. In this embodiment, exponential PCR amplification of the hairpin is enabled and sequences can be amplified directly from human genomic DNA. Following hairpin amplification, the PCR product is heat-denatured to allow the hairpins to separate from their complementary strand, and placed rapidly on ice. Because of the sudden cooling, cross-hybridization of different hairpins is minimal, and thus the original hairpins are reformed, following their amplification. By amplifying DNA in a hairpin-formation, polymerase-errors practically always end-up forming a mismatch. Genuine mutations, however, remain fully-matched. For example, if the polymerase introduces an A>G mutation on the upper strand of the original sequence, it is very unlikely that, during synthesis of the bottom strand of a single hairpin it will perform the exact opposite error (T>C mutation) at exactly the complementary-strand position. This can be seen when one looks at the normal probability for such a double-error. Even for a polymerase with a large error rate of 10−4/base the odds for a double-error event are 10−4×10−4×0.25=2.5×10−9, i.e. less than the expected spontaneous mutation rate in somatic tissues 1,24. On the other hand, practically all genuine mutations remain fully matched following hairpin-PCR, as these reside in both strands from the beginning (FIG. 1A). Preferably, the amplified hairpins that contain mismatches are efficiently separated from those that do not, using any procedure that recognizes mismatch. Preferred methods include dHPLC-mediated fraction collection and enzymatic based separation. Preferably, the hairpin caps are removed subsequent to the separation of hairpins containing mismatches from mismatch-free hairpins, thus allowing the original DNA sequence to be recovered. While the amplified DNA will have PCR-induced errors such errors can be removed from the amplified sample, which can now be processed for mutation detection without sensitivity being limited by polymerase errors. In a further preferred embodiment, DGGE, dHPLC, as well as methods based on the mismatch-binding protein MutS or Ce1I or resolvases (endo V) or exomucleases are used to separate the fraction of PCR-amplified sequences containing polymerase errors 7, 10, 25-27. These methods utilize the conversion of homoduplexes to heteroduplexes via cross-hybridization of PCR amplified products. Previously, both mutations and PCR errors are simultaneously converted to mismatches. When mutations are at a low frequency, practically all of them are converted to mismatches. Thus, such a means did not discriminate them from PCR errors. By the present method mutations and other preexisting changes do not appear as mismatches. The present method of using a hairpin structure takes advantage of the fact that genuine mutations are witnessed in both upper and lower DNA strands while PCR errors occur on one strand at a time. Forcing DNA polymerase to copy both strands in one pass creates ‘a double record’ of the sequence. Thus, effectively the method boosts the replication fidelity and converts PCR errors, but not other changes to mismatches. The method of the present invention has wide applicability. For example, polymerase slippage errors produce ‘stutter’ banding that complicate microsatellite analysis of single 19, or pooled samples 28. Scanning for very low frequency changes occurring naturally in somatic tissues (<1 mutant in 107 alleles, 1) or at early stages of carcinogenesis will enable identification of tumor signatures as markers for early tumor detection 6. Identification of low level mutations in somatic tissues will also facilitate elucidation of carcinogen-specific mutational fingerprints following environmental exposures 17. Reliable screening for traces of ‘onco-mutations’ 18,29 can enhance the clinical and diagnostic utility of minimal residual disease detection 30 and the identification of mutations in bodily excretions 31. For investigating the mechanisms of carcinogenesis, determination of carcinogen-induced mutational spectra in disease-related genes in non-tumorous tissues can provide evidence as to whether a specific mutagenic agent or pathway is involved in a particular disease or cancer. This high-selectivity mutational spectrometry will also help determine whether or not a mutator phenotype must be invoked to explain the acquisition of multiple mutations in tumor cells 18,32. Most previous studies of mutational spectra were based on phenotypic selection methods (e.g. HPRT, lacZ assays). These methods preclude analysis of genes and human tissues for which selective conditions cannot be devised in in-vitro single cell systems. Molecular methods with selectivity comparable to the spontaneous mutation frequency (10−7-10−8) that can be applied to all tissues are highly desirable 2, 17. However, the onset of PCR errors limits several approaches, such as CDCE, which would otherwise have the sensitivity needed to measure the spontaneous mutation frequency 1. Mutation scanning methods such as DGGE 33 or dHPLC 34 are particularly hampered by PCR errors since, by detecting all possible mutations, they are more likely than RFLP-based methods to encounter misincorporation ‘hotspots’ which result in false positives. Particularly for mutation detection from limited starting material, such as micrometastatic cells or laser capture microdissected samples, very large DNA amplification is required. The error rate of conventional PCR is then particularly problematic 4 as error containing sequences can comprise >30% of the overall population 27, making it almost impossible to identify genuine mutations. The present method changes that and it allows, for example dHPLC to overcome PCR errors and to perform reliable mutation analysis when starting from a few cells or from minute, laser capture microdissected specimens. RFLP-based methods can now be used to examine few sites for mutations relative to mutation scanning methods. When a sample is limited, such as in minute LCM-dissected samples, it previously was often not possible to perform more than a single PCR amplification towards the detection of mutations in one gene. With the present method, one can now perform mutation screening in several genes simultaneously from a single sample, for disease gene discovery or diagnostic applications. This ‘whole genome’ amplification method permits amplification of genomic DNA from small tissue samples in an error-free manner. This allows repeated multi-gene mutation screening from large collections of minute fresh or paraffin-embedded samples without being limited by available starting material or PCR errors. By removing PCR errors from amplified sequences, the present hairpin-PCR permits the use of well-established techniques such as dHPLC, CDCE, RFLP and microsatellite analysis for detecting traces of mutations in minute biopsies and for investigating the origins of cancer in human tissues without the introduction of polymerase-induced errors. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A-1C outline the generation of error-free amplified DNA via hairpin PCR. In FIG. 1A, the scheme for removing PCR errors following amplification of DNA in a hairpin structure is shown. FIG. 1B shows the expected structure and sequence of hairpin A. FIG. 1C shows the expected structure and sequence of hairpin D, an oligonucleotide encompassing both top and bottom strands of p53 exon 9. FIGS. 2A-2H show PCR amplification and dHPLC separation of hairpin-shaped oligonucleotides. FIG. 2A, lanes 1-5 show the PCR product of hairpins A,B,C,E, and D, respectively. Lanes 6 and 7 of FIG. 2A show amplification of hairpin D with only forward or only reverse primer. FIG. 2B shows amplification of hairpin C using Advantage Titanium® (lane 1), Pfu Turbo® (lane 3) or Advantage HF2® (lane 5) polymerases respectively; lanes 2, 4 and 6 are water-controls (no template) in each case. FIG. 2C shows quantitative real time PCR of hairpin D: curves 1-4, starting material of 1 ng, 100 pg, 10 pg and 1 pg respectively. FIG. 2D shows hairpin PCR (lanes 1 and 2, in duplicate) followed by denaturation and rapid cooling of the product (lanes 3 and 4, in duplicate). FIG. 2E shows hairpin D amplified with primers that bind the non-complementary ends, and either not extending (lane 1) or extending 9 bases into the hairpin sequence (lane 2). FIG. 2F shows spiking of p53 exon 9-containing hairpin D into 100 ng p53-negative HL-60 genome, followed by hairpin PCR using Advantage Titanium® polymerase. Spiking of 0.01 pg hairpin D corresponds to adding a single p53 exon 9 allele in the genome. Lanes 1-6, hairpin D addition of 0, 0. 1, 1, 10, 100, 1000 pg respectively. FIG. 2G is similar to FIG. 2F, but using Advantage HF2® polymerase. Lanes 1-5, hairpin D addition of 0, 0.01, 0.1, 1, 10 pg. FIG. 2H shows dHPLC-based separation of 1:1 mixtures of homoduplex and heteroduplex hairpins. The threshold of the fraction collector is set on the trailing (slowest) portion of the homoduplex. FIGS. 3A-3B show conversion of a DNA sequence to a hairpin and PCR amplification. FIG. 3A shows the procedure used to convert a native DNA sequence, flanked by two different restriction sites, into a hairpin with non-complementary ends that can be amplified. The hairpin-shaped oligonucleotides Cap1 and Cap2 are ligated to the 5′ and 3′ of both sequence ends. During hairpin PCR, primers extending into the sequence are used to confer sequence specificity. FIG. 3B shows conversion of a native p53 sequence flanked by Taq I/Alu I sites to a hairpin, followed by hairpin-PCR. Lane 1: Hairpin-PCR product obtained by applying the scheme in FIG. 1A for an isolated p53 sequence. Lane 2: Hairpin-PCR product obtained by applying the scheme in FIG. 1A to human genomic DNA, in order to directly amplify the same Alu I/Taq I target sequence depicted in Lane 1. Lane 3: As in lane 2, but omitting the addition of ligase from scheme FIG. 1A. Lanes 4 and 5: As in lane 2, but omitting the forward or reverse primer, respectively, from PCR. FIGS. 4A and 4B depict two preferred DNA structures. FIG. 4A depicts a DNA structure with a hairpin at one and non-complementary ends at the other end. FIG. 4B depicts a DNA structure with hairpins at both ends of the double-stranded DNA. FIG. 5 depicts the use of hairpin-shaped DNA as a detector for radiation and/or chemical exposures. The DNA strand breaks off following a strand break anywhere in the shaded area (target), thereby allowing the primers to bind and to PCR amplify the DNA segment. The amount of PCR amplification is proportional to how many DNA molecules undergo strand breaks and therefore it can be used to quantify the amount of radiation or chemical agent interacting with the DNA. Finally, the fraction of DNA molecules that remain intact can be re-amplified by using primers binding to the non-complementary linkers, thereby regenerating the original DNA detector molecule. FIG. 6 shows amplification of hairpins using rolling-circle amplification (RCA). The hairpin-shaped oligonucleotide of FIG. 6A was self-ligated to form a closed ‘dumbbell-like’ structure resembling the structures used for RNA-interference. The dumbbell was then amplified in an isothermal rolling-circle amplification reaction using Phi29 polymerase (from New England Biolabs) and random primers. Following digestion of the RCA product with Alu, the amplified hairpin-dimer DNA was recovered. FIG. 6B shows in lane 1, no Alu digestion; in lane 2, digestion with Alu. The amplification is about 1000-fold. In another example, the hairpin-shaped oligonucleotide of FIG. 6C was self-ligated to form a closed ‘dumbbell-like’ structure, and then amplified in an isothermal rolling-circle amplification reaction using Phi29 polymerase (from New England Biolabs) and random primers. Following digestion of the RCA product with Nla-III, the amplified hairpin-dimer DNA was recovered. FIG. 6D shows in lane 1, no digestion Nla-III; lane 1: with Nla-III digestion). The amplification is about 500-fold. DETAILED DESCRIPTION OF THE INVENTION We have discovered compositions and a method to amplify a target nucleic acid sequence, sometimes referred to as the template, that substantially reduces polymerase induced errors in a sequence of interest, and which can supply existing technologies with the necessary ‘selectivity leap’. The first step of the method involves converting the sequence of interest into a hairpin, which contains a double stranded region linked at one end through a single stranded loop, and performing PCR on the hairpin-structure. In the second step, the amplified PCR products are heat denatured and rapidly cooled, to convert each amplified PCR product into a hairpin: genuine polymorphisms or mutations will remain fully matched in the hairpin, whereas PCR products which contain a PCR induced error will form a hairpin that contains a mismatch in the double-stranded region. Thereafter, one removes those amplified nucleic acids which contain a mismatch by standard means. This method results in an amplified target nucleic acid which is substantially free of polymerase induced errors. Any method of converting the nucleic acid to a hairpin with non-complementary ends can be used. As used herein, hairpin structures include hairpins and dumbbells. Preferably, one uses oligonucleotide ‘caps’ which, in a single ligation step allow the conversion of a native DNA sequence to a ‘hairpin with non-complementary ends’. For example, one transforms the template nucleic acid, preferably DNA, into a hairpin by capping it at one end, Cap1. Cap1 is sometimes referred to as a ‘joining structure,’ because once it is ligated to the nucleic acid sequence of interest it joins the upper strand of the nucleic acid sequence of interest to the lower strand of the same nucleic acid molecule. Preferably, one caps the template at the other end, Cap2. Cap 2 is sometimes referred to as a priming structure, because it contains regions of single-stranded nucleic acid to which primers can bind to initiate the polymerization reaction. Caps1 and 2 naturally form hairpins on their own, to allow their respective ligation to the double stranded DNA ends of the template DNA. In addition, Cap2 contains a region with two non-complementary sequences to allow subsequent primer binding. Finally, Cap2 contains a ‘polymerase block’ approximately at the center. This ‘block’ can be one or more synthetic abasic sites; or a deoxynucleotide analogue that does not allow polymerase synthesis; or a uracil that, upon treatment with uracil glycosylase and heating is converted to a strand break, thus effectively providing the ‘polymerase block’. Any of the above mentioned polymerase blocks will enable the formation of a ‘hairpin with non-complementary ends during the subsequent PCR amplification. See FIG. 4. Alternatively, Cap2 or the priming structure can be a pair of oligonucleotides with are complementary to each other at the ends ligated to the nucleic acid of interest, and non-to each other at their other ends. In one preferred embodiment of the present invention, unbalanced concentrations of primers are used during PCR (‘asymmetric PCR’) such that the result of amplification is a single stranded nucleic acid product (i.e. monomer hairpins) instead of a double stranded product (dimer hairpins). In this embodiment, denaturation-renaturation of the DNA is unnecessary. In contrast to the method developed by Jones et al. (Jones and Winistorfer, 1992) (‘panhandle PCR’) where the overall structure is in a stem-loop shape but the ‘template DNA’ is not in a hairpin formation, the present hairpin PCR has the template DNA itself in a hairpin formation. This allows replication of both top and bottom strands of the template in a single pass of the DNA polymerase and subsequent conversion of polymerase errors to mismatches. Gupte et al., U.S. Pat. Nos. 6,251,610; 6,258,544; and 6,087,099, describe the generation of a DNA hairpin during PCR, by joining top and bottom DNA strands, in order to allow DNA sequencing of both strands in one pass. However, because their procedure requires polymerase extension (i.e. PCR) to generate the DNA strand-joining, it cannot be used to eliminate PCR errors since by the time the two strands are joined together some of the errors can have already occurred. (i.e. since they start by a regular PCR reaction they have already ‘lost the game’ in step 1). Oligonucleotide primers useful in the present invention can be synthesized using established oligonucleotide synthesis methods. Methods of synthesizing oligonucleotides are well known in the art. Such methods can range from standard enzymatic digestion followed by nucleotide fragment isolation (see for example, Sambrook, et al., Molecular Cloning: A Laboratory Manual, Second Edition, Cold Spring Harbor, N.Y., (1989), Wu et al, Methods in Gene Biotechnology (CRC Press, New York, N.Y., 1997), and Recombinant Gene Expression Protocols, in Methods in Molecular Biology, Vol. 62, (Tuan, ed., Humana Press, Totowa, N.J., 1997), the disclosures of which are hereby incorporated by reference) to purely synthetic methods, for example, by the cyanoethyl phosphoramidite method using a Milligen or Beckman System 1Plus DNA synthesizer (for example, Model 8700 automated synthesizer of Milligen-Biosearch, Burlington, Mass. or ABI Model 380B). Synthetic methods useful for making oligonucleotides are also described by Ikuta et al., Ann. Rev. Biochem. 53:323-356 (1984), (phosphotriester and phosphite-triester methods), and Narang et al., Methods Enzymol., 65:610-620 (1980), (phosphotriester method). Protein nucleic acid molecules can be made using known methods such as those described by Nielsen et al., Bioconjug. Chem. 5:3-7 (1994). As used herein, the term “primer” has the conventional meaning associated with it in standard nucleic acid procedures, i.e., an oligonucleotide that can hybridize to a polynucleotide template and act as a point of initiation for the synthesis of a primer extension product that is complementary to the template strand. Many of the oligonucleotides described herein are designed to be complementary to certain portions of other oligonucleotides or nucleic acids such that stable hybrids can be formed between them. The stability of these hybrids can be calculated using known methods such as those described in Lesnick and Freier, Biochemistry 34:10807-10815 (1995), McGraw et al., Biotechniques 8:674-678 (1990), and Rychlik et al., Nucleic Acids Res. 18:6409-6412 (1990). The template nucleic acid that is to be amplified in a hairpin formation is preferably DNA, but it can also be RNA or a synthetic nucleic acid. The template can be of any size, but preferably of a size that can be replicated by DNA or RNA polymerases; most preferably the template in the region 50 bp-1000 base pairs. The nucleic acid target can be any double stranded nucleic acid which is capable of being amplified. The target nucleic acid can be from any source, such as a PCR product of a known gene or a preparation of genomic DNA. The preferred target nucleic acid is DNA, but MRNA can also be used. The DNA can be any mixture containing one or various sizes of DNA, such as cDNA synthesized from the whole MRNA collected from cells that need to be screened for mutation/polymorphism; or fractions thereof; or the whole genomic DNA collected from cells that need to be screened for mutation/polymorphism; or fractions thereof; or any combination of the above digested into smaller pieces by enzymes. Any method of amplifying a nucleic acid target can be used. The amplification reaction can be polymerase chain reaction (PCR), ligase chain reaction (LCR), strand displacement amplification (SDA), transcription mediated amplification (TMA), Qβ-replicase amplification (Q-beta), or rolling circle amplification (RCA). Preferably, PCR is used to amplify the nucleic acid target. Any polymerase which can synthesize the desired nucleic acid may be used. Preferred polymerases include but are not limited to Sequenase, Vent, and Taq polymerase. Preferably, one uses a high fidelity polymerase (such as Clontech HF-2) to minimize polymerase-introduced mutations. In one preferred embodiment, rolling circle amplification (RCA) is used to amplify the nucleic acid template. Rolling circle amplification (RCA) is an isothermal process for generating multiple copies of a sequence. In rolling circle DNA replication in vivo, a DNA polymerase extends a primer on a circular template (Komberg, A. and Baker, T. A. DNA Replication, W. H. Freeman, New York, 1991). The product consists of tandemly linked copies of the complementary sequence of the template. RCA is a method that has been adapted for use in vitro for DNA amplification (Fire, A. and Si-Qun Xu, Proc. Natl. Acad Sci. USA, 1995, 92:4641-4645; Lui, D., et al., J. Am. Chem. Soc., 1996, 118:1587-1594; Lizardi, P. M., et al., Nature Genetics, 1998, 19:225-232; U.S. Pat. No. 5,714,320 to Kool). In RCA techniques a primer sequence having a region complementary to an amplification target circle (ATC) is combined with an ATC. Following hybridization, enzyme, dNTPs, etc. allow extension of the primer along the ATC template, with DNA polymerase displacing the earlier segment, generating a single stranded DNA product which consists of repeated tandem units of the original ATC sequence. RCA techniques are well known in the art, including linear RCA (LRCA). Any such RCA technique can be used in the present invention. When RCA is used to amplify the hairpin structure, Cap2 should not contain a polymerase block’ in order to allow the enzyme to continuously perform DNA synthesis on the circularized DNA template. In this approach, following ligation of Cap 1 and Cap 2 a polymerase reaction is initiated by addition of a single primer that binds to the Cap 2 non-complementary region. The polymerase then extends the primer by performing numerous circles around the original template, and resulting in a DNA amplification that copies both DNA strands every time it performs a full circle. Similar to non-isothermal amplification, during isothermal amplification too, every time there is a polymerase error during amplification it will form a ‘mismatch’ while genuine changes such as mutations will be ‘fully matched’. Following amplification, the original DNA sequence can be recovered with a restriction digestion which separates the DNA ‘caps’ introduced in the first step of the procedure. It is possible that instead of ligating Cap1 and Cap2 to the template DNA for the purpose of generating a hairpin structure with non complementary ends, the same result can be achieved via utilization of the first few steps described in the Gupte et al patents, referred to above. Thus, by using specially designed primers and only the first two PCR cycles, the top and bottom DNA strands become joined. After that, instead of performing further PCR cycling, as the Gupte patent suggests, one proceeds by ligating Cap2 which contains non-complementary ends to the template DNA. Subsequently, hairpin PCR can be performed. The advantage of converting the DNA molecule to a hairpin in this manner is that no Cap1 ligation is required, and that the template DNA sequence does not need to be flanked by two different enzymatic restriction sites anymore. The disadvantage is that, if there is a polymerase-generated error during the 2-cycle initial primer extension, this will not form a mismatch and therefore cannot be eliminated at later stages in the assay. This alternative way of performing hairpin-PCR is simpler and can be useful in some instances where a complete elimination of PCR errors is not required. In fact, if a polymerase with a high-proofreading ability is used, performing just two cycles of PCR should typically not introduce many errors. Following hairpin PCR, the amplified sequences are denatured and cooled rapidly, so that polymerase errors are converted to mismatches. Mismatch containing DNA can be eliminated by a number of means known is the art. For example, using a physical separation technique such as size separation or an enzymatic means size separation methods including: Denaturing HPLC (dHPLC); denaturing gradient gel electrophoresis, DGGE; constant denaturant gel electrophoresis, CDGE; constant denaturant capillary electrophoresis, CDCE; heteroduplex analysis (HET)-based gels, etc. Alternatively, the fraction of DNA molecules containing mismatches can be eliminated or reduced via binding to mismatch-recognizing enzymes. Any known mismatch-binding enzyme can be used. For example, MutS protein; or mismatch-binding glycosylases MutY or TDG; or Ce1 I; or mismatch-binding endonucleases, or resolvases. In one preferred embodiment, the mismatch-containing DNA is degraded by contact with a combination of a mismatch-binding enzyme (to create a strand break at the mismatch) and exonuclease III (to preferentially degrade the DNA which contains a strand break). A similar degradation of mismatch-containing DNA has previously been reported (Nelson et al., 1993). This procedure will enrich the sample in sequences that do not contain mismatches (PCR errors). In one preferred embodiment, DNA amplification in a hairpin structure via rolling circle isothermal amplification can be used for RNA interference (RNAi). In this embodiment, nucleic acid molecules in a hairpin structure can be introduced into cells by any known method, for example by direct microinjection or via insertion into a vector and subsequent transfection of cells. In certain cases, these hairpin molecules need to be amplified prior to their microinjection. The direct amplification of hairpin RNAi molecules using the methods of the present application offers practical advantages. Cheng et al., Mol. Genet. Metab. 80: 121-128 (2003); Kittler et al., Sem. Cancer Biol. 13: 259-265 (2003). Molecular beacon approaches to the specific detection of DNA sequences (Tyagi and Kramer, 1996) require the construction of hairpin-shaped probes that interact with the template sequence during real time PCR. With the hairpin structure of the present method, the template sequence itself is in a hairpin shape, thus it can serve as the molecular beacon, obviating the need for a specific probe. In this approach, the primers used during hairpin-PCR amplification are fluorescently labeled, so that the resulting hairpins are fluorescent and can display the properties of molecular beacons (i.e. fluorescent quenching and de-quenching during amplification). The method of the present invention can be used to detect DNA damage, for example damage caused by exposure to radiation and chemicals. PCR amplification is suppressed when the primer binding sites are located within a double-stranded nucleic acid, e.g. the hairpin portion of the sequence of interest, but not if primers bind in a single stranded portion of the sequence. This property can allow the nucleic acid hairpins of the present invention to serve as ‘radiation/DNA damage detector’ molecules. If radiation generates a strand break in certain regions, e.g. the shaded areas in FIG. 5, then a portion of the hairpin breaks-off during PCR, generating two single-stranded pieces of DNA (representing the top strand and the bottom strand in FIG. 5), which are no longer contiguous due to the presence of the DNA damage. Thus, if PCR is performed on a hairpin structure using two primers which are complementary to sequences on the top strand of the hairpin, then in the absence of DNA damage, the region remains double stranded and the primers cannot bind or amplify the DNA, but in the presence of even a small amount of DNA damage, the top strand is now single stranded, which allows primer binding and PCR amplification. The amount of PCR product produced is proportional to the radiation dose or to the DNA damage induced. In this embodiment, any agent can be included which protects against the generation of spontaneous strand breaks, which can be induced by the heating and cooling applied during PCR. For example, to avoid any heating-generated strand breaks, hydroxylamine can be added to the PCR reaction to prevent heat-generated abasic sites from becoming strand breaks. Because the hairpin contains also the non-complementary linkers, the radiation dosimeter can be replicated at will by the methods described above, thus providing ‘infinite’ amounts of starting material. By miniaturizing and arraying many PCR reaction chambers one can obtain an entire profile of radiation doses over an area (i.e. resulting in a ‘radiation imaging’ device). Finally, because nucleic acid such as DNA is part of every cell in the body, it is possible to utilize for example the DNA as an intrinsic probe for measuring radiation or chemical exposures (‘biodosimetry’). In this approach, following radiation/chemical exposure DNA will be extracted from cells, digested, and converted to a hairpin shape. One can use multiple primer sites depending upon the size of the starting template. If the radiation/chemical exposure resulted in a strand break, appropriate placement of the PCR primers should yield a product, while if there is no strand break no product will be produced. The ability to convert DNA to a dosimeter, combined with the DNA functionality should also allow in-vivo targeting of molecular regions with this dosimeter. The oligonucleotide primers of the present invention can be coupled to any molecule of interest (e.g. an indicator fluorescent molecule) using any method which allows the primer and the molecule of interest to be coupled. In one preferred embodiment, the N-terminal amino acid of each molecule is cysteine, and the oligonucleotides carry a thiol group at the 3′ or 5′ end, to allow coupling to the N-terminal cysteine. One preferred molecule of interest is an indicator fluorescent molecule. Coupling may be accomplished by any chemical reaction that will bind the molecule to the primer so long as the primer remains able to bind the hybridization site in the nucleic acid target and form a duplex, allowing PCR amplification. This linkage can include many chemical mechanisms, for instance covalent binding, affinity binding, intercalation, coordinate binding and complexation. The preferred binding is, however, covalent binding. For example, for a protein, covalent binding can be achieved either by direct condensation of existing side chains or by the incorporation of external bridging molecules. Many bivalent or polyvalent linking agents are useful in coupling protein molecules to other molecules such as the primers of the present invention. For example, representative coupling agents can include organic compounds such as thioesters, carbodiimides, succinimide esters, disocyanates, glutaraldehydes, diazobenzenes and hexamethylene diamines. This listing is not intended to be exhaustive of the various classes of coupling agents known in the art but, rather, is exemplary of the more common coupling agents (see Killen and Lindstrom, J. Immunol. 133:1335-2549, 1984; Jansen, F. K., et al., Imm. Rev. 62:185-216, 1982; and Vitetta et al., supra). Preferred linkers are described in the literature. See, for example, Ramakrishnan, S., et al., Cancer Res. 44: 201-208 (1984), describing the use of MBS (M-maleimidobenzoyl-N-hydroxysuccinimide ester). See also Umemoto et al., U.S. Pat. No. 5,030,719, describing the use of a halogenated acetyl hydrazide derivative coupled to an antibody by way of an oligopeptide linker. Particularly preferred linkers include: (i) EDC (1-ethyl-3-(3-dimethylamino-propyl) carbodiimide hydrochloride; (ii) SMPT (4-succinimidyloxycarbonyl-alpha-methyl-alpha-(2-pyridyl-dithio)-toluene (Pierce Chem. Co., Cat. (21558G); (iii) SPDP (succinimidyl-6[3-(2-pyridyldithio) propionamido] hexanoate (Pierce Chem. Co., Cat #21651G); (iv) Sulfo-LC-SPDP (sulfosuccinimidyl 6 [3-(2-pyridyldithio)-propianamide] hexanoate (Pierce Chem. Co. Cat. #2165-G); and (v) sulfo-NHS (N-hydroxysulfo-succinimide: Pierce Chem. Co., Cat. #24510) conjugated to EDC. The linkers described above contain components that have different attributes, thus leading to conjugates with differing physio-chemical properties. For example, sulfo-NHS esters of alkyl carboxylates are more stable than sulfo-NHS esters of aromatic carboxylates. NHS-ester containing linkers are less soluble than sulfo-NHS esters. Further, the linker SMPT contains a sterically hindered disulfide bond, and can form conjugates with increased stability. Disulfide linkages, are in general, less stable than other linkages because the disulfide linkage is cleaved in vitro resulting in less conjugate available. Sulfo-NHS, in particular, can enhance the stability of carbodimide couplings. Carbodimide couplings (such as EDC) when used in conjunction with sulfo-NHS, forms esters that are more resistant to hydrolysis than the carbodimide coupling reaction alone. In one preferred embodiment, the molecules are proteins which contain an N-terminal cysteine, which can be coupled to an oligonucleotide carrying a thiol group at either the 3′ or 5′ end and a donor or acceptor at the 5′ or 3′ end, respectively. In this embodiment it is desirable to substitute any other cysteines in the protein to other amino acids. In another preferred embodiment, the present invention provides kits suitable for amplifying a nucleic acid of interest to generate a substantially error-free amplified product. Said kits comprise at least a single stranded first and second non-complementary nucleic acid for ligation to the first end of the double stranded nucleic acid of interest, or a cap of single stranded nucleic acid, where the cap contains a sequence midway in the cap (such as an abasic site) that cannot be amplified by PCR, and where the sequences on either side of this sequence are non-complementary. Said kits also comprise a cap for ligation to the second end of the double stranded nucleic acid of interest, such that the upper and lower strands of the nucleic acid are contiguous, creating the hairpin structure. The kit further comprises two primers for amplification of the hairpin, as described above. Such kits may optionally include the reagents required for performing amplification reactions, such as DNA polymerase, DNA polymerase cofactors, and deoxyribonucleotide-5′-triphosphates. Optionally, the kit may also include various polynucleotide molecules, DNA or RNA ligases, restriction endonucleases, reverse transcriptases, terminal transferases, various buffers and reagents, and antibodies that inhibit DNA polymerase activity. The kits may also include reagents necessary for performing positive and negative control reactions. Optimal amounts of reagents to be used in a given reaction can be readily determined by the skilled artisan having the benefit of the current disclosure. PCR-based amplification is used in almost every aspect of genetic diagnosis, DNA cloning, mutation detection and basic research. The present method can reduce the number of PCR associated errors by at least 1-2 orders of magnitude. Thus, one can now use PCR based techniques, to identify cancer cells at an early stage (Sidransky et al., 1997), to detect mutations in single cells (Liu et al., 2002) or to reliably identify minimal residual disease (Bartram et al., 1990). Previously, in all these applications, polymerase misincorporations invariably became disguised as mutations and result to false positives (Reiss et al., 1990). EXAMPLES Example 1 Amplification of Hairpins Using Polymerase Chain Reaction (PCR) Hairpin-Forming, Long Oligonucleotides Five long oligonucleotides expected to form hairpins were synthesized by Oligos Etc and HPLC-purified (Oregon, USA). The sequence of hairpins A and D (SEQ ID NOs: 1 and 2, respectively) are depicted in FIGS. 1B-C. Sequences of hairpin B (SEQ ID NO:3), hairpin C (SEQ ID NO:4), and hairpin E (SEQ ID NO:5), which were designed to contain non-complementary ends like hairpin D, were: Hairpin B: 5′ ACC GAC GTC GAC TAT CCG GGA (SEQ ID NO:3) ACA CAT GAT TTA AAT GTT TAA ACA CGC GGT GGA CTT AAT TAA CTA GTG CCT TAG GTA GCG TGA AAG TTA ATT AAG TCA CCG CAT GTT TAA ACA TTT AAA TGT ACA GCA CTC TCC AGC CTC TCA CCG CA 3′; Hairpin C: 5′ ACC GAC GTC GAC TAT CCG GGA (SEQ ID NO:4) ACA CAA GAT TTA AAT GTT TAA ACA CGC GGT GAC TTA ACA GGC GCG CCT TAA CTA GTG CCT TAG GTA GCG TGA AAG TTA AGG CGC GCC TGT TAA GTC ACC GCG TGT TTA AAC ATT TAA ATC TTG AGC ACT CTC CAG CCT CTC ACC GCA 3′; Hairpin E: 5′ ACC GAC GTC GAC TAT CCG GGA (SEQ ID NO:5) ACA GAT CCA TGC ACT GCC CAA CAA CAC CAG CTC CTC TCC CCA GCC AAA GAA GAA ACC ACT GGA TGG AGA ATA TTT CGA CCC TTC AGA AAA CTG AAG GGT CGA AAT ATT CTC CAT CCA GTG GTT TCT TCT TTG GCT GGG GAG AGG AGC TGG TGT TGT TGG GCA GTG CAT GGA TCA GCA CTC TCC AGC CTC TCA CCG CA 3′. Hairpin-PCR Designated amounts of hairpins B-D were used in a 25 μl PCR reaction using Titanium Advantage® polymerase (Clontech, Palo Alto, Calif.) and forward primer 5′-GTG AGA GGC TGG AGA GTG CT-3′ (SEQ ID NO:6); and reverse primer 5′-ACG TCG ACT ATC CGG GAA CA-3′ (SEQ ID NO:7). PCR thermo-cycling conditions were: 94°, 30 sec; (94°, 30 sec/68°, 60 sec)×25 cycles; 68°, 60 sec; 4°; Hold. The PCR products were then examined via ethidium-stained agarose gel electrophoresis. Alternatively, PCR amplification was conducted using high fidelity Advantage HF-2R polymerase (Clontech) or Pfu Turbo® (Strategene Inc). In addition, using the same thermocycling conditions, quantitative real time PCR in the presence of SYBR Green I dye was performed in a Cepheid I SmartCycler™ machine. Primers used for PCR of hairpin A were forward primer 5′ TAA ATG TTT AAA CAC GCG GT 3′ (SEQ ID NO:8); and reverse primer 5′ TAA ATG TTT AAA CAT GCG GT 3′ (SEQ ID NO:9). To amplify picogram amounts of hairpin D spiked into 100 ng human genomic DNA from HL-60 cells, touchdown PCR was applied: 94°, 30 sec; (94°, 20 sec/65°, 20 sec/68°, 20 sec)×30 cycles, with annealing temperature decreasing 1°/cycle; (94°, 10 sec/55°, 20 sec/68°, 20 sec)×15 cycles; 68°, 6 min; 4°; Hold. dHPLC Analysis of Olizonucleotide Hairpins To perform separation of mixtures of heteroduplex and homoduplex hairpins, 1 ng hairpins were injected into a WAVE™ dHPLC system (Transgenomics Inc, Cambridge, Mass.) and run under denaturing conditions at different temperatures, following the company-supplied protocol (see Transgenomics et al., www.transgenomics.com). The dHPLC system was equipped with a fraction collector that allows selection of the elution product according to the DNA retention time on the dHPLC column. Conversion of Native DNA Sequences to a Hairpin, and PCR Amplification The forward primer 5′AGG CCT TCA TGA CTG ATA CCA 3′ (SEQ ID NO: 10) and reverse primer 5′ TGA GAT CGA CTG AGA CCC CAA 3′ (SEQ ID NO:11) were used to amplify from genomic DNA a 137 bp p53 sequence (nucleotides 2215-2352 of Genbank sequence #X54156) flanked by Taq I and Alu I restriction sites near each end. Following double digestion of this sequence with Taq I (65° C., 1 h) and Alu I (37° C., 1 h) the restricted p53 DNA fragment was purified via QIAquick™ centrifugation columns (Qiagen Inc, Valencia, Calif.) and then ligated to the hairpin-shaped sequences Cap1 (SEQ ID NO:12): 5′ (phosphate)-CGACGGCGCGCCGCCTTAGGTAGCGTTAGGCGCGCCGT-3′, which ligates Taq I sites; and Cap2 (SEQ ID NO: 13), 5′ (phosphate)-CTGCCGAGTTCCTGCTTTGAGATGCTGTTGAGUUACGTCGACTATCCTTGAAC ACCAACTCGGCAG-3′ which ligates Alu I (blunt) sites, following the protocol described by Horie and Shimada (Horie et al., 1994). Briefly, ligation of the two caps to DNA was performed by adding a 100-fold molar excess of each Cap into 10 μM DNA template in the presence of T4 DNA polymerase and incubating the 50 μl reaction volume overnight at 15° C. 2 μl ligation mixture were then treated with uracil glycosylase (Roche Diagnostics), at 37° C., 30 min, in the company-supplied buffer, 20 μl final volume, in a PCR tube. Upon addition of PCR components and buffer, a reaction was carried out using Titanium polymerase for 35 cycles and the following thermocycling conditions: 94°, 30 sec; (94°, 30 sec/68°, 60 sec)×25 cycles; 68°, 60 sec; 4°; Hold. Primers that bind the ligated Cap2 and overlap the target p53 sequence by 12 bases were used in this PCR reaction: forward primer (SEQ ID NO: 14) 5′ ATGAGATGGGGTCAGCTGCCTTCATCGGCGCGCCCATGATTT 3′; and reverse primer (SEQ ID NO:15) CTTCTCCCCCTCCTCTGTTGCTCATCGGCGCGCC 3′. Next, the same p53 sequence flanked by Taq I and Alu I sites was converted to a hairpin and amplified from human genomic DNA. 1 μg human genomic DNA from an osteosarcoma cell line (ATCC CRL-1543) was digested with Taq I, purified and then digested with Alu I. The protocol described above was used to ligate, treat with uracil glycosylase and PCR amplify the target sequence from digested genomic DNA using the same primers and thermocycling conditions. PCR products were examined via ethidium stained gel electrophoresis. Amplified sequences were then excised from the gel (QIAquick™ gel extraction kit, Qiagen Inc.), and sequenced via dideoxy-sequencing at the Dana Farber Molecular Biology Core Facility. The primer used for sequencing were the same with those used during the hairpin PCR reaction. RESULTS AND DISCUSSION Amplification of DNA Hairpins With Non-Complementary Ends The observation that, if DNA is amplified in a hairpin structure mismatches should be almost always separated from mutations urged the development of hairpin PCR. Indeed, if the polymerase introduces an A>G mutation on the upper DNA strand it is unlikely that, during synthesis of the bottom strand of a single hairpin it will perform the exact opposite error (T>C mutation) at the same position of the complementary strand. Even for a polymerase with a large error rate of 10−4/base the odds for a double-error event are 10−4×10−4×0.25=2.5×10−9, i.e. less than the expected spontaneous mutation rate in somatic tissues (Khrapko et al., 1994). On the other hand, practically all genuine mutations should remain fully matched following hairpin-PCR, as these reside in both strands from the beginning (FIG. 1A). This complete discrimination of polymerase errors from the mutations should allow subsequent isolation of error-free amplified hairpins by one of many strategies, such as dHPLC (Xiao et al., 2001), CDCE (Khrapko et al., 1994), DGGE (Cariello et al., 1991) or enzymatic depletion of mismatches using mismatch recognition proteins, MutS (Smith et al., 1997), MutY (Chakrabarti et al., 2000), TDG (Pan et al., 2002). To confirm the basic technical aspects of this approach, we designed long oligonucleotides (B,C,D,E, 149, 168, 200, and 218 nucleotides respectively) expected to form hairpins with non-complementary ends which do not inhibit primer binding at their ends (FIG. 1C), as well as a regular hairpin A, 131 bp, which lacks the non-complementary ends (FIG. 1B), for comparison. Hairpins D and E encompass the complete sequence of p53 exon 9. 1 ng each hairpin was then used in a 25 μl PCR reaction using Titanium Advantage® polymerase and primers designed to operate on the non-complementary ends of hairpins B-D, or alternatively on the complementary ends of hairpin A. Hairpins B-D produce a PCR product, while hairpin A does not (FIG. 2A, lanes 1-5). The data indicate that hairpins are readily amplified as long as primers are allowed to bind, and the polymerase is able to synthesize the hairpin complement, presumably by displacing the opposite strand. Omission of either forward or reverse primers abolishes the product (FIG. 2A, lanes 6-7) which indicates that amplification requires both primers and that the full length hairpin is replicated by the polymerase. Hairpin PCR was repeated using two proof-reading polymerases, Pfu Turbo™, or Advantage-HF2 and amplification was obtained (FIG. 2B). FIG. 2C depicts quantitative real-time hairpin-PCR profiles of hairpin D serial dilutions, using SYBR Green I dye. The exponential nature of amplification is evident. Because of the way hairpin-PCR operates (FIG. 1A), the PCR products are expected to result to double-stranded DNA molecules, each strand of which is a full hairpin. To separate the two strands, and to recover the original hairpins, following purification of the PCR product the samples are denatured at 95° C., 1 min, and rapidly cooled by placing them directly on ice. This procedure does not allow time for substantial cross-hybridization of different DNA strands, while each strand is expected to rapidly form a hairpin due to its self-complementary sequence. FIG. 2D demonstrates that rapid cooling converts the hairpin amplification product (lanes 1 and 2) to a band approximately half the size (lanes 3 and 4), which corresponds to the expected monomer hairpin. Next, the forward and reverse primers used for the amplifications in FIG. 2A were re-designed to encompass an additional 9 nucleotide extension (20+9=29mers) inside the p53 exon 9 hairpin D sequence. FIG. 2E demonstrates that, although the 3′-end of the primers falls within the hairpin portion of the sequence, amplification remains almost unhindered. The data are consistent with the occurrence of primer binding by means of the 20 base overlap with the non-complementary end of the hairpin, and that the 3′ end of the primers temporarily displaces the hairpin sequence. This ‘invasion’ by hybridized oligonucleotides at the DNA ends, also reported by Guilfoyle et al. (1997), presumably happens frequently enough to allow polymerase binding and primer extension to occur. Therefore restricting the primers on the non-complementary ends amplifies every hairpin sequence that contain those ends, while using primers with 3′ ends extending into the hairpin sequence renders hairpin-PCR sequence specific. To investigate the amplification efficiency of hairpin PCR, 100 ng purified human genomic DNA from a cell line that lacks the p53 gene (HL-60 cells), was mixed with decreasing amounts of the p53 exon 9-containing hairpin D. One human genome (˜3×109 bp), is ˜1.5×107 times the size of hairpin D therefore spiking 10−2 pg hairpin D into 100 ng genomic DNA is approximately equivalent to adding a single copy p53 exon 9 in a hairpin formation in the genome. FIGS. 2F and 2G demonstrate hairpin PCR amplification of p53 exon 9 using two different polymerases. Amplification from 0.01-0.1 pg hairpin D in the presence of genomic DNA is obtained. The amplification efficiency of hairpin PCR appears comparable to that of regular PCR. DHPLC Separation of Homoduplex From Heteroduplex Hairpins To confirm that hairpins containing a single base mismatch, such as those expected to result from polymerase misincorporations, can be distinguished from fully-matched hairpins via dHPLC, we injected homoduplex hairpin D into a WAVE™ dHPLC system equipped with a fraction collector. Two more hairpins were synthesized. These were identical to the homoduplex hairpin except that they were synthesized to contain sequence changes, 56G>A (SEQ ID NO:16) or 46insACA (SEQ OD NO:17), respectively 5′ ACC GAC GTC GAC TAT CCG GGA SEQ ID NO: 16 ACA CAA GAT TTA AAT GTT TAA ACA CAC GGT GAC TTA ACA GGC GCG CCT TAA CTA GTG CCT TAG GTA GCG TGA AAG TTA AGG CGC GCC TGT TAA GTC ACC GCG TGT TTA AAC ATT TAA ATC TTG AGC ACT CTC CAG CCT CTC ACC GCA 3′; 5′ ACC GAC GTC GAC TAT CCG GGA SEQ ID NO: 17 ACA CAA GAT TTA AAT GTT TAA ACA ACA CAC GGT GAC TTA ACA GGC GCG CCT TAA CTA GTG CCT TAG GTA GCG TGA AAG TTA AGG CGC GCC TGT TAA GTC ACC GCG TGT TTA AAC ATT TAA ATC TTG AGC ACT CTC CAG CCT CTC ACC GCA 3′. Upon folding, these hairpins form mismatches which simulate a potential misincorporation by Taq polymerase (Smith et al., 1997) and a Taq slippage error (Perlin et al., 1995), respectively. 1 ng each heteroduplex and homoduplex hairpin was injected separately into dHPLC, or, alternatively, mixed (1:1) and injected as a mixture. At a partially denaturing temperature of 61° C., the peaks from the heteroduplex hairpins could be distinguished from the fully-matched, homoduplex hairpin, FIG. 2H. Setting the threshold of the fraction collector on the trailing part of the homoduplex peak allows the collection of mainly (70-80%) homoduplex hairpin out of this mixture. This example simulated a worse case scenario, where the heteroduplex DNA was 50% of the overall sample. Normally however, the heteroduplex peak resulting from PCR errors will be a smaller fraction (˜1-10%) of the homoduplex peak (Wright et al., 1990). From the data in FIG. 2H it can be estimated that if PCR errors are confined to 10% or 1% of the sequences, one would collect >95% and >99% homoduplex DNA respectively, resulting to a radical elimination of heteroduplex hairpins from the mixtures. In dHPLC chromatography almost all possible base changes and PCR errors are detectable (Transgenomics, www.transgenomic.com), however individual base changes can result to varying degrees of separation of heteroduplexes from the homoduplex peak (Xiao et al., 2001). Nevertheless, homoduplex DNA tends to have the longest retention time on the column (Xiao et al., 2001). By re-cycling the collected homoduplex through the dHPLC for a second time and by collecting the trailing portion of the homoduplex each time should practically filter-out the misincorporations. Conversion of Native DNA Sequences to Hairpins and PCR Amplification To enable the scheme in FIG. 1A, conversion of a native DNA fragment to a hairpin that can be amplified directly from human genomic DNA is required. To convert a sequence to a hairpin with non-complementary ends we performed ligation of two different oligonucleotide ‘caps’, Cap1 and Cap2, at the positions of two restriction sites encompassing the sequence (FIG. 3A). Cap1 and Cap2 are small oligonucleotides designed to form a hairpin that ligates both top and bottom strands at the respective DNA restriction site (Horie et al., 1994). In addition, Cap2 contains two centrally-located uracils. Following the simultaneous ligation of both caps at the two DNA ends, a treatment with uracil glycosylase removes the uracils and generates abasic sites at the center of Cap2. During the heating step of the subsequent PCR reaction the glycosylase is inactivated and a strand break is expected to form via beta elimination at the abasic sites (Longo et al., 1990) which allows the hairpin to obtain a structure that can be PCR-amplified. To demonstrate the application, a 91 bp p53 sequence flanked by Alu I and Nla-III restriction sites was generated following a double digestion of a larger DNA fragment which had been first amplified from genomic DNA using regular PCR. Following ligation of caps 1 and 2, the resulting 145 bp fragment was amplified using primers overlapping the non-complementary linkers and the p53 sequence itself. A ˜290 bp double stranded product was observed (FIG. 3B, lane 1). Next, human genomic DNA expected to generate the same Alu I/Taq I-flanked p53 fragment following a double enzymatic digestion was subjected to the same procedure. A ˜290 bp was generated when the full scheme of FIG. 3A was applied (FIG. 3B, lane 2) but not when DNA ligase was omitted (FIG. 3B, lane 3) or when a single primer was used in the hairpin-PCR reaction (FIG. 3B, lanes 4 and 5). The DNA fragment was then excised from the gel and sequenced. Sequencing verified that the correct sequence had been amplified and that the expected hairpin structure of the amplified sequence had formed. Both unknown and known mutation detection methods are affected by PCR errors and the most selective methods are those that are affected most. The principal limitation for mutation scanning via constant denaturant capillary electrophoresis (CDCE) is the fidelity of the polymerase used (Keohavong et al., 1989; Andre et al., 1997). High selectivity mutation scanning via DGGE and dHPLC is ultimately limited by polymerase error rate ( Keohavong et al., 1989; Transgenomics, www.transgenomic.com; Cariello et al., 1991). Some of the high selectivity assays for RFLP-based known mutation detection (PCR/RE/LCR (Wilson et al., 2000); Radioactivity-based PCR-RFLP (Nakazawa et al., 1990); RSM (Steingrimsdottir et al., 1996; Jenkins et al., 1998); APRIL-ATM (Kaur et al., 2002) and others reviewed in Parsons et al., 1997, utilize PCR in at least one stage prior to RFLP-selection. Therefore these are also limited by PCR errors (McKinzie et al., 2001). The ability to amplify DNA without being limited by polymerase-introduced errors would significantly impact mutation detection and cancer diagnosis. A mismatch-binding protein, MutS, was previously used to deplete mismatches caused by PCR errors, in order to improve DNA synthesis fidelity (Smith et al., 1997). However, low frequency genuine mutations are also converted to mismatches and eliminated in this process, thus there is no benefit to mutation detection. In contrast hairpin PCR converts polymerase errors to mismatches while also retains mutations in the homoduplex DNA. Forcing the enzyme to keep a double record of the sequence effectively boosts the DNA replication fidelity, as it is unlikely that a misincorporation will happen at the same position in both DNA strands simultaneously. We demonstrated amplification of small (75-145 bp) sequences in hairpin formation. However polymerases can displace much longer (>1 kb) DNA stretches during synthesis (Lizardi et al., 1998). With appropriate adaptation it is possible to amplify large genomic fractions in a hairpin formation. Accordingly, a genome-wide depletion of PCR errors will allow accurate genome-wide genotyping from limited starting material. We have demonstrated that DNA hairpins designed to have non-complementary ends are efficiently PCR amplified and that dHPLC can discriminate among homoduplex and heteroduplex hairpins. Native DNA sequences can be converted to a hairpin structure and amplified from human genomic DNA. Example 2 Amplification of Hairpins Using Rolling-Circle Amplification FIG. 6 shows amplification of hairpins using rolling-circle amplification (RCA). The hairpin-shaped oligonucleotide of FIG. 6A was self-ligated to form a closed ‘dumbbell-like’ structure resembling the structures used for RNA-interference. The dumbbell was then amplified in an isothermal rolling-circle amplification reaction using Phi29 polymerase (from New England Biolabs) and random primers. Following digestion of the RCA product with Alu, the amplified hairpin-dimer DNA was recovered. FIG. 6B shows in lane 1, no Alu digestion; in lane 2, digestion with Alu. The amplification is about 1000-fold. 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N Engl J Med, 322: 61, 1990. 39. Wright, P. A. and Wynford-Thomas, D. The polymerase chain reaction: miracle or mirage? A critical review of its uses and limitations in diagnosis and research. J Pathol, 162: 99-117, 1990. 40. Keohavong, P. and Thilly, W. G. Fidelity of DNA polymerases in DNA amplification. Proc Natl Acad Sci U S A, 86: 9253-9257, 1989. 41. Ennis, P., Zemmour, J., Salter, R., and Parham, P. Rapid Cloning of HLA-A,B cDNA by Using the Polymerase Chain Reaction: Frequency and Nature of Errors Produced in Amplification. PNAS, 87: 2833-2837, 1990. 42. Liu, Q., Swiderski, P., and Sommer, S. S. Truncated amplification: a method for high-fidelity template-driven nucleic acid amplification. Biotechniques, 33: 129-132, 134-126, 138, 2002. 43. Perlin, M. W., Lancia, G., and Ng, S. K. Toward fully automated genotyping: genotyping microsatellite markers by deconvolution. Am J Hum Genet, 57: 1199-1210, 1995. 44. Parsons, B. L. and Heflich, R. H. Genotypic selection methods for the direct analysis of point mutations. Mutat Res, 387: 97-121, 1997. 45. Khrapko, K., Coller, H., Andre, P., Li, X. C., Foret, F., Belenky, A., Karger, B. L., and Thilly, W. G. Mutational spectrometry without phenotypic selection: human mitochondrial DNA. Nucleic Acids Res, 25: 685-693, 1997. 46. Sidransky, D. Nucleic acid-based methods for the detection of cancer. Science, 278: 1054-1059, 1997. 47. Bartram, C. R., Yokota, S., Hansen-Hagge, T. E., and Janssen, J. W. Detection of minimal residual leukemia by polymerase chain reactions. Bone Marrow Transplant, 6 Suppl 1: 4-8, 1990. 48. Reiss, J., Krawczak, M., Schloesser, M., Wagner, M., and Cooper, D. N. The effect of replication errors on the mismatch analysis of PCR-amplified DNA. Nucleic Acids Res, 18: 973-978, 1990. 49. Diatchenko, L., Lau, Y. F., Campbell, A. P., Chenchik, A., Moqadam, F., Huang, B., Lukyanov, S., Lukyanov, K., Gurskaya, N., Sverdlov, E. D., and Siebert, P. D. Suppression subtractive hybridization: a method for generating differentially regulated or tissue-specific cDNA probes and libraries. Proc Natl Acad Sci USA, 93: 6025-6030, 1996. 50. Transgenomics, I. Single Nucleotide Polymorphism (SNP), Insertion & Deletion on the WAVE® Nucleic Acid Fragment Analysis System. http://www.transgenomic.com/pdf/AN112.pdf, 2002. 51. Horie, K. and Shimada, K. Gene targeting by a vector with hairpin-shaped oligonucleotide caps. Biochem Mol Biol Int, 32: 1041-1048, 1994. 52. Khrapko, K., Andre, P., Cha, R., Hu, G., and Thilly, W. G. Mutational spectrometry: means and ends. Prog Nucleic Acid Res Mol Biol, 49: 285-312, 1994. 53. Li-Sucholeiki, X. C. and Thilly, W. G. A sensitive scanning technology for low frequency nuclear point mutations in human genomic DNA. Nucleic Acids Res, 28: E44, 2000. 54. Xiao, W. and Oefner, P. J. Denaturing high-performance liquid chromatography: A review. Hum Mutat, 17: 439-474, 2001. 55. Khrapko, K., Hanekamp, J. S., Thilly, W. G., Belenkii, A., Foret, F., and Karger, B. L. Constant denaturant capillary electrophoresis (CDCE): a high resolution approach to mutational analysis. Nucleic Acids Res, 22: 364-369, 1994. 56. Cariello, N. F., Swenberg, J. A., De Bellis, A., and Skopek, T. R. Analysis of mutations using PCR and denaturing gradient gel electrophoresis. Environ Mol Mutagen, 18: 249-254, 1991. 57. Smith, J. and Modrich, P. Removal of polymerase-produced mutant sequences from PCR products. Proc Natl Acad Sci USA, 94: 6847-6850, 1997. 58. Chakrabarti, S., Price, B. D., Tetradis, S., Fox, E. A., Zhang, Y., Maulik, G., and Makrigiorgos, G. M. Highly selective isolation of unknown mutations in diverse DNA fragments: toward new multiplex screening in cancer. Cancer Res, 60: 3732-3737, 2000. 59. Pan, X. and Weissman, S. M. An approach for global scanning of single nucleotide variations. Proc Natl Acad Sci USA, 99: 9346-9351, 2002. 60. Guilfoyle, R. A., Leeck, C. L., Kroening, K. D., Smith, L. M., and Guo, Z. Ligation-mediated PCR amplification of specific fragments from a class-II restriction endonuclease total digest. Nucleic Acids Res, 25: 1854-1858, 1997. 61. Transgenomics, I. Transgenomic Optimase™ Polymerase Delivers Highest Fidelity in PCR for WAVE® System Analysis (US); http://www.transgenomic.com/pdf/AN119u.pdf, 2002. 62. Longo, M. C., Beminger, M. S., and Hartley, J. L. Use of uracil DNA glycosylase to control carry-over contamination in polymerase chain reactions. Gene, 93: 125-128, 1990. 63. Andre, P., Kim, A., Khrapko, K., and Thilly, W. G. Fidelity and mutational spectrum of Pfu DNA polymerase on a human mitochondrial DNA sequence. Genome Res, 7: 843-852, 1997. 64. Cariello, N. F., Swenberg, J. A., and Skopek, T. R. Fidelity of Thermococcus litoralis DNA polymerase (Vent) in PCR determined by denaturing gradient gel electrophoresis. Nucleic Acids Res, 19: 4193-4198, 1991. 65. Wilson, V. L., Yin, X., Thompson, B., Wade, K. R., Watkins, J. P., Wei, Q., and Lee, W. R. Oncogenic base substitution mutations in circulating leukocytes of normal individuals. Cancer Res, 60: 1830-1834, 2000. 66. Nakazawa, H., Aguelon, A. M., and Yamasaki, H. Relationship between chemically induced Ha-ras mutation and transformation of BALB/c 3T3 cells: evidence for chemical-specific activation and cell type-specific recruitment of oncogene in transformation. Mol Carcinog, 3: 202-209, 1990. 67. Steingrimsdottir, H., Beare, D., Cole, J., Leal, J. F., Kostic, T., Lopez-Barea, J., Dorado, G., and Lehmann, A. R. Development of new molecular procedures for the detection of genetic alterations in man. Mutat Res, 353: 109-121, 1996. 68. Jenkins, G. J., Chaleshtori, M. H., Song, H., and Parry, J. M. Mutation analysis using the restriction site mutation (RSM) assay. Mutat Res, 405: 209-220, 1998. 69. Kaur, M., Zhang, Y., Liu, W. H., Tetradis, S., Price, B. D., and Makrigiorgos, G. M. Ligation of a primer at a mutation: a method to detect low level mutations in DNA. Mutagenesis, 17: 365-374, 2002. 70. Myers, R. M., Lumelsky, N., Lerman, L. S. & Maniatis, T. Detection of single base substitutions in total genomic DNA. Nature 313, 495-498 (1985). 71. Lizardi, P. M., Huang, X., Zhu, Z., Bray-Ward, P., Thomas, D. C., and Ward, D. C. Mutation detection and single-molecule counting using isothermal rolling-circle amplification. Nat Genet, 19: 225-232, 1998. All references described herein are incorporated by reference. | <SOH> BACKGROUND OF THE INVENTION <EOH>Substantial interest has been directed to the detection of changes in nucleic acid sequences, such as caused by mutation and methylation. For example, mutation in certain genes have been associated with a variety of disorders-ranging from blood disorders to cancers. Genetic testing is one way to find this information out. However, our ability to detect such mutations is limited by certain problems with a key component in these tests, namely the polymerase chain reaction (PCR). A major problem with PCR is that polymerases invariably generate errors during amplification. Such polymerase misincorporations can be indistinguishable from genuine mutations, and lower the quality of DNA cloning and protein functional analysis by in vitro translation. Polymerase misincorporations set a limit for molecular mutation detection methods: the most selective technologies invariably rely on PCR, but PCR also poses a final selectivity limit, typically 1 mutant in 10 5 -10 6 alleles, since all DNA polymerases generate errors during DNA synthesis which can be misinterpreted as mutations (false positives). Thus, high selectivity mutation detection technologies often fall short of the enormous selectivity needed to address issues like the generation of spontaneous mutations in somatic tissues 1,2 , the early detection of genomic instability 3 , the mutation screening of single cells 4 or the reliable detection of minimal residual disease 5, 6 . Both unknown and known mutation detection methods are affected by PCR errors and the most selective methods are affected most. For example, the principal limitation for mutation scanning via constant denaturant capillary electrophoresis (CDCE) is the fidelity of the polymerase used 7, 8 . High selectivity mutation scanning via DGGE and dHPLC is ultimately hindered by polymerase error rate 7, 9, 10 . Some of the highest sensitivity assays for RFLP-based known mutation detection, including PCR/RE/LCR 11 , MutEx-ACB-PCR 12 , Radioactivity-based PCR-RFLP 13 , RSM 14, 15 , APRIL-ATM 16 , and others reviewed in Parsons et al. 17 , utilize PCR in at least one stage prior to RFLP-selection, and are therefore also limited by PCR errors 18 . Accordingly, it would be desirable if one had a means of amplifying DNA free of polymerase-induced misincorporations, to detect mutations without being limited by polymerase-induced errors. This could significantly impact mutation detection, disease diagnosis, and cancer diagnosis. | <SOH> SUMMARY OF THE INVENTION <EOH>We have now discovered compositions and methods to amplify a target nucleic acid sequence, sometimes referred to as the template, that substantially reduces polymerase induced errors in a sequence of interest, and which can supply existing technologies with the necessary ‘selectivity leap’. The first step of this method involves converting the sequence of interest into a hairpin, which contains a double stranded region linked at one end through a single stranded loop, and performing PCR on the hairpin-structure. In the second step, the amplified PCR products are heat denatured and rapidly cooled, to convert each amplified PCR product into a hairpin: genuine polymorphisms or mutations will remain fully matched in the hairpin, whereas PCR products which contain a PCR induced error will form a hairpin that contains a mismatch in the double-stranded region. Thereafter, one removes those amplified nucleic acids which contain a mismatch by standard means. This method results in an amplified target nucleic acid which is substantially free of polymerase induced errors. In an alternative embodiment, amplification of the hairpin structure is performed using isothermal rolling circle amplification (RCA). True nucleic acid changes such as from a mutation can be separated from polymerase-generated single nucleotide changes, insertions, deletions, or slippage thereby providing practically error-less nucleic acid, preferably DNA. By using a hairpin sequence one can obtain a sample (template) from a range of sources such as from genomic DNA. Large fractions of the human genome can be amplified via hairpin PCR to provide faithfully—replicated genomic DNA for extensive, genome-wide screening for differences from a standard. This is particularly desirable when starting from limited amounts of biopsy material, i.e. from a few cells obtained via laser capture microdissection. Additional technical factors limit the overall selectivity of mutation detection (e.g. amount of DNA; mis-priming; heteroduplex formation; incomplete enzymatic digestion 15 ); however, with appropriate selection of conditions these problems can often be overcome. In contrast, PCR errors have been regarded as a ‘glass ceiling’ for mutation detection selectivity. The present method of using hairpin PCR will allow a boost to almost every existing method for highly selective mutation detection and lead to studies and diagnostic tests that were impossible with previous technology by substantially reducing the number of errors that are an artifact of PCR from the sample. This method will also improve microsatellite analysis by eliminating polymerase ‘slippage’ artifacts 19 and will also have application in other areas such as molecular beacons 20,21 and real time PCR, DNA cloning 22 or protein functional analysis by in vitro translation 4 . In one embodiment of the present invention, a hairpin with non-complementary ends can be efficiently PCR-amplified. In this embodiment, a target DNA sequence which needs to be PCR-amplified is first converted to a hairpin following ligation of an oligonucleotide ‘cap’ on one end and a pair of non-complementary linkers on the other end (See FIG. 1A ). Next, primers corresponding to the two non-complementary linkers are used in a PCR reaction that proceeds by displacing the opposite strand and amplifying the entire complement of the hairpin. In one preferred embodiment, these primers corresponding to the non-complementary linkers can overlap the sequence of interest, thus conferring sequence specificity. In this embodiment, exponential PCR amplification of the hairpin is enabled and sequences can be amplified directly from human genomic DNA. Following hairpin amplification, the PCR product is heat-denatured to allow the hairpins to separate from their complementary strand, and placed rapidly on ice. Because of the sudden cooling, cross-hybridization of different hairpins is minimal, and thus the original hairpins are reformed, following their amplification. By amplifying DNA in a hairpin-formation, polymerase-errors practically always end-up forming a mismatch. Genuine mutations, however, remain fully-matched. For example, if the polymerase introduces an A>G mutation on the upper strand of the original sequence, it is very unlikely that, during synthesis of the bottom strand of a single hairpin it will perform the exact opposite error (T>C mutation) at exactly the complementary-strand position. This can be seen when one looks at the normal probability for such a double-error. Even for a polymerase with a large error rate of 10 −4 /base the odds for a double-error event are 10 −4 ×10 −4 ×0.25=2.5×10 −9 , i.e. less than the expected spontaneous mutation rate in somatic tissues 1,24 . On the other hand, practically all genuine mutations remain fully matched following hairpin-PCR, as these reside in both strands from the beginning ( FIG. 1A ). Preferably, the amplified hairpins that contain mismatches are efficiently separated from those that do not, using any procedure that recognizes mismatch. Preferred methods include dHPLC-mediated fraction collection and enzymatic based separation. Preferably, the hairpin caps are removed subsequent to the separation of hairpins containing mismatches from mismatch-free hairpins, thus allowing the original DNA sequence to be recovered. While the amplified DNA will have PCR-induced errors such errors can be removed from the amplified sample, which can now be processed for mutation detection without sensitivity being limited by polymerase errors. In a further preferred embodiment, DGGE, dHPLC, as well as methods based on the mismatch-binding protein MutS or Ce1I or resolvases (endo V) or exomucleases are used to separate the fraction of PCR-amplified sequences containing polymerase errors 7, 10, 25-27 . These methods utilize the conversion of homoduplexes to heteroduplexes via cross-hybridization of PCR amplified products. Previously, both mutations and PCR errors are simultaneously converted to mismatches. When mutations are at a low frequency, practically all of them are converted to mismatches. Thus, such a means did not discriminate them from PCR errors. By the present method mutations and other preexisting changes do not appear as mismatches. The present method of using a hairpin structure takes advantage of the fact that genuine mutations are witnessed in both upper and lower DNA strands while PCR errors occur on one strand at a time. Forcing DNA polymerase to copy both strands in one pass creates ‘a double record’ of the sequence. Thus, effectively the method boosts the replication fidelity and converts PCR errors, but not other changes to mismatches. The method of the present invention has wide applicability. For example, polymerase slippage errors produce ‘stutter’ banding that complicate microsatellite analysis of single 19 , or pooled samples 28 . Scanning for very low frequency changes occurring naturally in somatic tissues (<1 mutant in 10 7 alleles, 1 ) or at early stages of carcinogenesis will enable identification of tumor signatures as markers for early tumor detection 6 . Identification of low level mutations in somatic tissues will also facilitate elucidation of carcinogen-specific mutational fingerprints following environmental exposures 17 . Reliable screening for traces of ‘onco-mutations’ 18,29 can enhance the clinical and diagnostic utility of minimal residual disease detection 30 and the identification of mutations in bodily excretions 31 . For investigating the mechanisms of carcinogenesis, determination of carcinogen-induced mutational spectra in disease-related genes in non-tumorous tissues can provide evidence as to whether a specific mutagenic agent or pathway is involved in a particular disease or cancer. This high-selectivity mutational spectrometry will also help determine whether or not a mutator phenotype must be invoked to explain the acquisition of multiple mutations in tumor cells 18,32 . Most previous studies of mutational spectra were based on phenotypic selection methods (e.g. HPRT, lacZ assays). These methods preclude analysis of genes and human tissues for which selective conditions cannot be devised in in-vitro single cell systems. Molecular methods with selectivity comparable to the spontaneous mutation frequency (10 −7 -10 −8 ) that can be applied to all tissues are highly desirable 2, 17 . However, the onset of PCR errors limits several approaches, such as CDCE, which would otherwise have the sensitivity needed to measure the spontaneous mutation frequency 1 . Mutation scanning methods such as DGGE 33 or dHPLC 34 are particularly hampered by PCR errors since, by detecting all possible mutations, they are more likely than RFLP-based methods to encounter misincorporation ‘hotspots’ which result in false positives. Particularly for mutation detection from limited starting material, such as micrometastatic cells or laser capture microdissected samples, very large DNA amplification is required. The error rate of conventional PCR is then particularly problematic 4 as error containing sequences can comprise >30% of the overall population 27 , making it almost impossible to identify genuine mutations. The present method changes that and it allows, for example dHPLC to overcome PCR errors and to perform reliable mutation analysis when starting from a few cells or from minute, laser capture microdissected specimens. RFLP-based methods can now be used to examine few sites for mutations relative to mutation scanning methods. When a sample is limited, such as in minute LCM-dissected samples, it previously was often not possible to perform more than a single PCR amplification towards the detection of mutations in one gene. With the present method, one can now perform mutation screening in several genes simultaneously from a single sample, for disease gene discovery or diagnostic applications. This ‘whole genome’ amplification method permits amplification of genomic DNA from small tissue samples in an error-free manner. This allows repeated multi-gene mutation screening from large collections of minute fresh or paraffin-embedded samples without being limited by available starting material or PCR errors. By removing PCR errors from amplified sequences, the present hairpin-PCR permits the use of well-established techniques such as dHPLC, CDCE, RFLP and microsatellite analysis for detecting traces of mutations in minute biopsies and for investigating the origins of cancer in human tissues without the introduction of polymerase-induced errors. | 20040115 | 20081118 | 20050630 | 92889.0 | 0 | BAUGHMAN, MOLLY E | AMPLIFICATION OF DNA IN A HAIRPIN STRUCTURE, AND APPLICATIONS | SMALL | 0 | ACCEPTED | 2,004 |
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10,758,663 | ACCEPTED | Unified interleaver/de-interleaver | An interleaver/de-interleaver that may be used for multiple interleaving algorithms and look up tables (LUTs) of one or more interleaving standards. In at least some embodiments, the interleaver/de-interleaver may comprise an initial value selector, offset selector, and a pruning adjuster coupled to a combining block. The interleaver/de-interleaver may further comprise a boundary regulator coupled to the combining block, wherein the boundary regulator is configurable to modify an output of the combining block according to one or more pre-determined rules. The interleaver/de-interleaver may further comprise a controller coupled to, at least, the initial value selector, the offset value selector, and the offset adjuster, whereby the interleaver/de-interleaver may be used to interleave or de-interleave a block of data in accordance with a plurality of interleaving algorithms. | 1. An interleaver/de-interleaver, comprising: an initial value selector configurable to select an initial value from a programmable set of initial values; an offset selector coupled to the initial value selector, the offset selector is configurable to select an offset value from a set of programmable offset values; a pruning adjuster coupled to the offset selector, the adjuster is configurable to modify the offset value; a boundary regulator coupled to the initial value selector, the offset selector, and the pruning adjuster, the boundary regulator is configurable to ensure a combination of the initial value with a selected offset value or a modified offset value are within a pre-determined index boundary; and a controller coupled to the initial value selector, the offset selector, and the pruning adjuster, the controller asserts control signals provided to the initial value selector, the offset selector, and the pruning adjuster, such that a plurality of interleaving/de-interleaving algorithms are executable. 2. The interleaver/de-interleaver of claim 1 wherein the initial value selector and the offset selector comprise multiplexers. 3. The interleaver/de-interleaver of claim 2 wherein the offset selector further comprises one or more accumulator/subtractors. 4. The interleaver/de-interleaver of claim 1 wherein the controller accesses a programmable table having adjustment values used by the boundary regulator. 5. The interleaver/de-interleaver of claim 1 wherein the pruning adjuster is configurable to adjust the value of the combination of the initial value with the selected offset value or the modified offset value. 6. The interleaver/de-interleaver of claim 1 further comprising a combining block coupled to the initial value selector, the offset selector, the pruning adjuster, and the boundary regulator, wherein the combining block is configurable to combine the initial value with the selected offset value or the modified offset value. 7. The interleaver/de-interleaver of claim 1 further comprising a parameter received by at least one selected from the group consisting of the initial value selector, the offset selector, the pruning adjuster, the boundary regulator, and the controller. 8. The interleaver/de-interleaver of claim 7 wherein the parameter is selected from the group consisting of: an initial vector input to the initial value selector; an initial vector selection control input to the initial value selector; an offset vector input to the offset selector; an accumulator/subtractor initial value input to the offset selector; an accumulator/subtractor update rate input to the offset selector; an adjustment value input to the boundary regulator; a subtract value input to the boundary regulator and the offset selector; a multiplexer select line control input to the initial value selector; a multiplexer select line control input to the offset selector; a number of address pointers value; a burst index calculation; and a code of blocks index calculation. 9. The interleaver/de-interleaver of claim 1 wherein the boundary regulator comprises an addition/subtraction block. 10. A method for interleaving/de-interleaving, comprising: receiving a configurable initial value; receiving a configurable offset value; combining an offset with the initial value; outputting an index value using the combination of the offset value with the initial value; and receiving changeable parameter values for a set of fixed parameters such that an interleaver/de-interleaver outputs an index according to a plurality of interleaving/de-interleaving techniques. 11. The method of claim 10 further comprising adjusting the offset value according to one of the parameter values. 12. The method of claim 10 further comprising adjusting the combination of the offset with the initial value according to one of the parameter values. 13. The method of claim 12 wherein adjusting the combination of the offset with the initial value comprises accessing a look-up table that contains adjustment values. 14. The method of claim 10 further comprising finishing a burst of data before starting another burst of data. 15. The method of claim 10 further comprising inputting a linearly increasing index as a sequence of initial values. 16. The method of claim 10 further comprising outputting a linearly increasing index. 17. A storage medium containing processor-readable instructions that are executable by a processor and cause the processor to: receive parameter values of a set of parameters, the set of parameters are used to implement a plurality of interleaving/de-interleaving techniques; select an initial value according to one of the parameters; select an offset value according to one of the parameters; combine the initial value with an offset; and output an index value associated with the combination of the initial value and the offset. 18. The storage medium of claim 17 wherein the processor-readable instructions further cause the processor to adjust the selected offset value according to one of the parameters. 19. The storage medium of claim 17 wherein the processor-readable instructions further cause the processor to adjust the combination of the initial value with the offset according to one of the parameters. 20. A system, comprising: means for inputting values of parameters that describe a plurality of interleaving/de-interleaving techniques; means for selecting an initial value from one of the parameters; means for selecting an offset value from one of the parameters; means for combining the initial value with an offset; and means for outputting an index value associated with a combination of the initial value with the offset as an index location for a bit of data. 21. The system of claim 20 further comprising means for modifying the offset value according to one of the parameters. 22. The system of claim 20 further comprising means for modifying the combination of the initial value with the offset according to one of the parameters. 23. An apparatus, comprising: a processor; a memory coupled to the processor; and a transceiver coupled to the processor, wherein the transceiver includes an interleaver/de-interleaver configurable for use with a plurality of interleaving or de-interleaving techniques according to an updatable set of parameter values. 24. The apparatus of claim 23 wherein the interleaver/de-interleaver comprises an initial value selector that selects an initial value for use with an interleaving or de-interleaving technique. 25. The apparatus of claim 23 wherein the interleaver/de-interleaver comprises an initial value generator that generates an initial value for use with an interleaving or de-interleaving technique. 26. The apparatus of claim 23 wherein the interleaver/de-interleaver comprises an offset value selector that selects an offset value for use with an interleaving or de-interleaving technique. 27. The apparatus of claim 23 wherein the interleaver/de-interleaver comprises a offset adjuster for adjusting an offset value for use with an interleaving or de-interleaving technique. 28. The apparatus of claim 27 wherein the offset adjuster is configurable to automatically adjust the offset value for an interleaving or de-interleaving technique in accordance with bit pruning techniques of at least one interleaving or de-interleaving technique. | FIELD OF THE INVENTION The present invention relates generally to wireless communication systems. BACKGROUND In wireless communication systems, block interleaving may be used to combat channel fading. Generally, interleaving re-orders bits of information to achieve time diversity of an original sequence of bits (i.e., interleaving changes the order of at least some bits in an original sequence with respect to time). When a transmitted interleaved signal is received, de-interleaving may be used to re-order the transmitted sequence back to the original sequence. A variety of interleaving schemes exist in different wireless standards. Even in the same standard, there may still be a variety of coding schemes that use different interleaving algorithms. For example, the GSM/GPRS/EDGE standard has more than 15 different interleaving algorithms, including various look-up tables (LUTs). Interleaving algorithms may vary in block size (i.e., the amount of bits in an index), level of interleaving, use of bit pruning, and other considerations as will later be described. Most interleaver/de-interleaver implementations may typically be tailored for use with a specified algorithm and may not easily be used with other algorithms. Being able to implement a plurality of different algorithms with one hardware and/or software solution is desirable. Furthermore, finding a multi-standard interleaving solution that does not require large amounts of memory and/or complex hardware is desirable. SUMMARY An interleaver/de-interleaver that may be used for multiple interleaving algorithms and look up tables (LUTs) of one or more interleaving standards. In at least some embodiments, the interleaver/de-interleaver may comprise an initial value selector, offset selector, and a pruning adjuster coupled to a combining block. The interleaver/de-interleaver may further comprise a boundary regulator coupled to the combining block, wherein the boundary regulator is configurable to modify an output of the combining block according to one or more pre-determined rules. The interleaver/de-interleaver may further comprise a controller coupled to, at least, the initial value selector, the offset value selector, and the pruning adjuster, whereby the interleaver/de-interleaver may interleave or de-interleave in accordance with a plurality of interleaving/de-interleaving techniques. BRIEF DESCRIPTION OF THE DRAWINGS For a detailed description of various embodiments of the invention, reference will now be made to the accompanying drawings in which: FIG. 1 illustrates a system for interleaving and/or de-interleaving in accordance with embodiments of the invention; FIG. 2 illustrates another system for interleaving and/or de-interleaving in accordance with embodiments of the invention; FIG. 3 illustrates a table of parameters for implementing an interleaving/de-interleaving algorithm using the system of FIG. 2; FIGS. 4A and 4B illustrate software code for implementing an interleaver/de-interleaver in accordance with embodiments of the invention; FIGS. 5A-5S illustrate tables of parameters and parameter values that may be used to implement algorithms found in the GSM 05.03 V8.5.0 Release 1999 standard in accordance with embodiments of the invention; FIGS. 6A-6B illustrate an interleaving algorithm (intra frame interleaving) according to a WCDMA standard found in 3GPP TS 25.212-v.3.5.0 (2000-12); FIGS. 6C-6D illustrate tables of parameters and parameter values that may be used to implement the WCDMA standard of FIGS. 6A-6B in accordance with embodiments of the invention; FIGS. 6E-6F illustrate a 30×30 look-up table (LUT) that may be used to implement the de-interleaver of the WCDMA standard of FIGS. 6A-6B in accordance with embodiments of the invention; FIGS. 7A-7E illustrate tables of parameters and parameter values that may be used to implement algorithms of the IS2000 standard referenced in 3GPP2 C.S0002-C Version 1.0 in accordance with embodiments of the invention; FIG. 8 illustrates a system that implements an interleaver/de-interleaver in accordance with embodiments of the invention; and FIG. 9 illustrates a method for interleaving/de-interleaving data in accordance with embodiments of the invention. While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. Notation and Nomenclature Certain terms are used throughout the following description and claims to refer to particular system components. As one skilled in the art will appreciate, companies may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . ”. Also, the term “couple” or “couples” is intended to mean either an indirect or direct electrical connection. Thus, if a first device couples to a second device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections. DETAILED DESCRIPTION The subject matter disclosed herein generally relates to wireless communication systems. As previously mentioned, block interleaving may be used in wireless communications to combat channel fading. An interleaver (or de-interleaver) may be described as a look-up table (“LUT”) or a set of equations where mods (i.e., modulus functions), multipliers, and dividers are used so that an arbitrary index can be mapped to its interleaved index. As an example, consider wireless voice transmission (e.g., cell phones). At a first cell phone, the voice of a user may be processed as blocks of data. The blocks of data and/or bits within each block may be interleaved, such that bits of data that were ordered consecutively are now separated by other bits. The interleaved blocks of data may be transmitted by the first cell phone and received by a second cell phone. At the second (receiving) cell phone, the blocks of data may be de-interleaved (i.e., the original data sequence is restored) so that a user of the second cell phone may hear the voice characterized by the original blocks of data. The interleaving and de-interleaving process may reduce fading effects during wireless transmission of the voice data by spreading out interference. In addition to interleaving/de-interleaving, other measures (e.g., modulation, encoding) may be used to reduce channel fading. In some embodiments, the function of interleavers and de-interleavers may be described as a non-linear differential equation: index(i+1)=index(i)+f′(i, other_parameters), i=0, 1, . . . , N−1 (1) where N is the interleaver/de-interleaver block length, index ( ) is the interleaved index, and f′ is a non-linear function that provides the distance (delta) for two consecutive input bits. For implementation convenience this equation may be rewritten as: index(i+1)=index(0)+f(i, other_parameters), i=0, 1, . . . , N−1 (2) where N is the interleaver/de-interleaver block length, index (0) is the first interleaved value of the original index, and f is a non-linear function that provides the distance (delta) for two consecutive input bits. The function f(i, other_parameters) may be decomposed into two parts: an offset part and an adjustment part. The offset part may calculate an offset relative to the initial value “index (0)”, while the adjustment part may change the value of the calculated offset in case the calculated offset is not desired (e.g., in bit pruning cases). Bit pruning removes unwanted bits of data from a data stream (e.g., a data stream associated with an interleaver algorithm) and compensates for spaces that are left in a data stream after unwanted bits have been removed. For example, a data block of arbitrary length may have a number of unrelated control bits that have been inserted between data bits of the data block. When de-interleaving, the control bits need to be taken out of the data block to prevent corruption of the data. As another example, in the WCDMA (Wideband Code Division Multiple Access) standard, an interleaving algorithm may write to a N×30 array, where N is the number of rows and 30 is the fixed number of columns. Because the data block length may be arbitrary, the last row of this array may not have exactly 30 elements. Therefore, there may be some blank bits in the last row. Consequently, when an interleaver reads the array column by column, those blank bits need be pruned in the interleaving algorithm. As previously mentioned, the function f may be non-linear and may comprise modulus, multiplication, and division operations, or alternatively may comprise an LUT that provides the offset distances with respect to an index origin, e.g., index (0). In order to simplify implementation of an interleaver/de-interleaver, embodiments of the invention may constrain the input or output of the index to be linear (i.e., linearly increasing). For example, if an input to an interleaver is linear, the output may be a “randomly” indexed output sequence. Alternatively, if an output of an interleaver is linear, the input may be “random”. This constraint satisfies operational environments in which a block of data is processed bit by bit as an input or an output. By using linear input or output indices, embodiments of the invention may replace multiplier(s), modulus operator(s), and divider(s) commonly used for function f with accumulator(s), subtractor(s), and counters, respectively. In some embodiments, the elements of equation (2) may be vectorized, i.e, the initial index value “index (0)”, the mapped index “index(i+1)”, and the components of the f function are vectors wherein each element of the initial vectors may be viewed as the first value of each column in a matrix. Additionally, the offset part of f may be unified as a vectorized module operator “mod(kΔ,c)”, where k is a linearly increasing auxiliary index, Δ is a difference vector, and c is a constant module value. In such embodiments, only accumulator(s) and subtractor(s) may be needed to implement the mod(kΔ,c) operation because of the linearity of k. FIG. 1 illustrates a block diagram of an interleaving/de-interleaving system 100 in accordance with embodiments of the invention. As shown in FIG. 1, the system 100 may comprise an initial value selector/generator 102, an offset selector 104, a pruning adjuster 106, a combining block 108, a controller 112, and a boundary regulator 114. As shown in FIG. 1, the initial value selector/generator 102 may couple to the controller 112 and the combining block 108. The offset selector 104 may couple to the controller 112, the pruning adjuster 106, and the combining block 108. The pruning adjuster 106 may couple to the controller 112, the offset selector 104, and the combining block 108. The combining block 108 may couple to the initial value selector/generator 102, the offset selector 104, the pruning adjuster 106, the controller 112, and the boundary regulator 114. The boundary regulator 114 may couple to the combining block 108, the controller 112, and an address calculator 116. The address calculator 116 may also couple to the controller 112. As illustrated in FIG. 1, the initial value selector/generator 102 may receive as input an initial vector having one or more values. Additionally, the initial vector may comprise a plurality of vectors. In at least some embodiments, the initial vector may comprise one or more predetermined vectors that may correspond to a particular algorithm and/or whether the system 100 is used for interleaving or de-interleaving. Additionally, or alternatively, the initial vector may be programmable. In operation, the initial value selector/generator 102 may select an initial vector value and output that value to the combining block 108. In at least some embodiments, a control signal 122 from the controller 112 may determine which initial vector value is selected and output to the combining block 108. Additionally or alternatively, the initial value selector/generator 102 may generate initial values. Therefore, in at least some embodiments an initial value vectors may not be used. The offset selector 104 may receive as input an offset vector having one or more values. In at least some embodiments, the offset vector may comprise a predetermined vector that corresponds to a particular interleaving algorithm and/or whether the system 100 is used for interleaving or de-interleaving. Additionally, or alternatively, the offset vector may be programmable. In operation, the offset selector 104 may select an offset vector value and output that value to the combining block 108. In at least some embodiments, a control signal 124 from the controller 112 may determine which offset vector value is selected and output from the offset selector 104 to the combining block 108. Additionally, the offset selector 104 may receive an input from the pruning adjuster 106, whereby an adjusted offset value is output to the combining block 108. The pruning adjuster 106 may change (i.e., adjust) the value of the offset value received by the offset selector 104. In at least some embodiments, the pruning adjuster 106 function according to a control signal 126 from the controller 112. For example, the pruning adjuster 106 may adjust the offset value by adding or subtracting an amount determined by the control signal 126. Additionally, or alternatively, the pruning adjuster 106 may change add or subtract a value from the combining block 108 operation according to the control signal 128 as will later be explained. For example, there may be interleaving/de-interleaving algorithms in which using a fixed offset value is undesirable (such as when bit pruning is used). Accordingly, in at least some embodiments, the pruning adjuster 106 in coordination with the controller 112 may implement a bit pruning mechanism as previously described. Additionally, or alternatively, the pruning adjuster 106 may be used to account for interleaving algorithms that implement “burst mapping” (e.g., at least some algorithms in the GSM standard implement burst mapping). Burst mapping may comprise another level of interleaving (e.g., block diagonal interleaving in the GSM standard). In some embodiments, each burst may comprise a number of interleaved data blocks with bits from different data blocks ordered consecutively. The combining block 108 receives an output value from the initial value selector/generator 102, the offset selector 104, and the pruning adjuster 106. By combining these outputs, the combining block 108 creates an “offset index position” that may be used to interleave or de-interleave a single bit of an index of bits. As the name infers, the offset index position may be an index position that is offset (i.e., separated) from some original or “base” index position. The base index position may be a predetermined starting address of a block of data (e.g., “index 0” as described previously). In some embodiments, the base index position may be a previous offset index position. The offset index position may be received by a boundary regulator 114, which functions to output an index position within the boundaries of a predetermined index. In some embodiments, the boundary regulator may determine if the offset index position is within the index boundary of a predetermined index. If the offset index position is within the index boundary, that offset index position may be output from system 100 for use with interleaving or de-interleaving a block of data. If the offset index position is not within the index boundary, an adjustment may be made so that the offset index position is modified to be within the index boundary. In some embodiments, one or more pre-determined rules may be used to modify an offset index position when necessary. For example, a predetermined index number (i.e., amount) may be subtracted from the offset index position so that the offset index position is moved to within the boundaries of the index (i.e., a modulus operation may be performed). In at least some embodiments, the amount subtracted from the offset index position may be equal to the data block size. More specifically, if an index [0:455] is to be interleaved, then an amount of 456 may be subtracted from an offset index position that is not within the [0:455] boundary. Assuming that the resultant index position is generated by an addition of an initial index value and a positive offset, the offset index position may possibly exceed the upper boundary of an index. A more detailed example will later be described. The output of the boundary regulator 114 may be used by an address calculator 116 to interleave or de-interleave a block of data. The address calculator 116 may also be a vector of multiple addresses wherein different indexes may be combined with different base addresses. FIG. 2 illustrates another embodiment of an interleaving/de-interleaving system 101 in accordance with embodiments of the invention. As shown in FIG. 2, the system 101 may comprise an initial value selector/generator 102, an offset selector 104, an pruning adjuster 106, a combining block 108, a controller 112, and a boundary regulator 114. The initial value selector/generator 102 may couple to the controller 112 and the combining block 108. The offset selector 104 may couple to the controller 112, the pruning adjuster 106, and the combining block 108. The pruning adjuster 106 may couple to the controller 112, the offset selector 104, and the combining block 108. The combining block 108 may couple to the initial value selector/generator 102, the offset selector 104, the pruning adjuster 106, the controller 112, and the boundary regulator 114. The boundary regulator 114 may couple to the combining block 108, the controller 112, and an address calculator 116. The address calculator 116 may also couple to the controller 112. As shown in FIG. 2, the initial value selector/generator 102 may comprise a multiplexer 134 that couples to another multiplexer 132 and an initial value generator 136. The offset selector may comprise a multiplexer 142 that couples to one or more accumulator/subtracters (ACSs) 144. The outputs of the ACSs 144 may couple to another multiplexer 146. The controller 112 may comprise a control unit 152 coupled to a select logic/table 154. The combining block 108 may comprise a summer. The boundary regulator 114 may comprise an adder/subtracter (ADS) 162. In operation, the initial value selector/generator 102 may select an initial value from an initial vector (“VI”) according to a control signal (“VI_SEL”) 122 from controller 112. Alternatively, the initial value generator 136 of the initial value selector/generator 102 may generate an initial value as directed by the controller 112. The multiplexer 134 may select to output either a generated value from the generator 136 or a selected value from the multiplexer 132 in accordance with a control signal from the controller 112. The output of the initial value selector/generator 102 is input to the combining block 108. As previously mentioned, the offset selector 104 may comprise multiplexers 142, 146 and one or more ACSs 144. The multiplexer 142 may select a value from a delta vector (“VD”) according to a control signal 124 (“B1”, “B0”) from the controller 112. The selected delta vector (“VD”) value may be input to the one or more ACSs 144, which may add or subtract an amount to the delta value. For example, the controller 112 may provide an initial value (“VI_ACS”) and a subtract value (“SUB_V” or “SUBTRACT_V”) to the ACSs 144. The VI_ACS value may provide a base value to which the VD value described above may be combined with (i.e., added to). The SUB_V value may be subtracted from the combination of VD and VI_ACS. In at least some embodiments, the ACSs 144 may function according to the Algorithm 1 shown below. Algorithm 1 accumulatorbase=VI_ACS; For each clock cycle, If accumulatorACS>=SUBTRACT_V outputACS=accumulatorACS−SUBTRACT_V; Else outputACS=accumulatorACS; End if accumulatorbase=accumulatorACS+VDselected. As shown in Algorithm 1, the ACSs 144 may implement an initial base value (“accumulatorbase”) equal to a parameter value (“VI_ACS”). For example, if VI_ACS equals two, the first accumulator value (“accumulatorAcs”) will equal two rather than zero. For each clock cycle, each ACS 144 may calculate a new accumulatorACS value. As shown in Algorithm 1, if the current accumulatorACS value is greater than or equal to a parameter value (“SUBTRACT_V”) the output (“outputAcs”) of an ACS 144 may be equal to accumulatorACS−SUBTRACT_V. Otherwise, the outputACS value may equal the accumulatorACS value. If the accumulatorbase value is equal to the combination of the accumulatorACS value and the VDselected value, the ACSs 144 have completed a cycle of interleaving (i.e., the outputACS values will begin to repeat) for a particular interleaving algorithm. The multiplexer 146 may receive the outputs of the ACSs 144 and select/output a value according to a control signal from the controller 112. The output of the offset selector 104 may be combined with the output initial vector value by the combining block 108. The pruning adjuster 106 may function with the controller 112 to control bit pruning and burst mapping as previously described. Accordingly, the pruning adjuster 106 may output a signal to the combining block 108, whereby the output of the combining block 108 (the offset index value previously described) may be adjusted. As shown in FIG. 2, the pruning adjuster 106 may function in accordance with a control signal 126 from the control unit 152 of the controller 112. In at least some embodiments, the pruning adjuster 106 may function to add, update and/or adjust values stored in the select logic/table 154 of the controller. In some embodiments, the system 101 may automatically account for bit pruning values based on a set of parameters. Therefore, no time (e.g., clock cycles) is wasted to discard unwanted bit index values. As previously described, the output of the combining block 108 may be called an offset index value. The offset index value may be input to the boundary regulator 114, which may ensure the index value is within the index boundary as previously described. In operation, the ADS 162 of the boundary regulator 114 may receive the offset index value from the combining block 108 and a control signal from the control unit 152 of the controller 112. For example, the control signal may indicate whether the ADS 162 should add or subtract one or more pre-determined values. In at least some embodiments, the ADS 162 may function according to the Algorithm 2 shown below. Algorithm 2 sumADS=VIselected+offsetselected+prune_valueselected; If sumADS>=SUBTRACT_V outputADS=sumADS−SUBTRACT_V; Else outputADS=sumADS. As shown in algorithm 2, the ADS 162 may calculate a sum value (“sumADS”) by summing a selected initial value (“VIselected”) with a selected offset value (“offsetselected”) and a selected prune value (“prune_valueselected”). If sumADS is greater than or equal to a parameter value “SUBTRACT_V” (also called “SUB_V”), then the output (“outputADS”) of the ADS 162 may equal sumADS−SUBTRACT_V. Otherwise, outputADS may equal sumADS. The output of the ADS 162 may be used as an output value of the interleaver/de-interleaver 101. The output of the interleaver/de-interleaver 101 may be input to an address calculator 116 as previously described. As shown in FIG. 2, the address calculator 116 may combine a base address and the interleaver/de-interleaver output value (also called an offset index value) to output an interleaved or de-interleaved index of addresses. In some embodiments, the controller 112 may function in conjunction with the address calculator 116 to interleave/de-interleave a block a data to and/or from multiple blocks of base addresses. In at least some embodiments, the systems 100, 101 may allocate bits of data to a burst such that one burst is completed before the next burst is created. When a burst has been completed, that burst may be transmitted. In contrast, other interleaver/de-interleavers follow a pattern in which all of the bursts receive a single bit of data before any of the bursts receive the second bit of data. The process of allocating one bit to each burst is typically repeated until all of the bursts are filled to capacity. Therefore, some embodiments of the invention may require less memory to buffer data bursts prior to transmission than others interleavers and/or de-interleavers that buffer all (or nearly all) data to bursts before transmitting. As an example, consider a data block having 64 bits of data to interleave/de-interleave. More specifically, an interleaver may interleave the 64 bits according to the following pattern of bit index positions: [0, 30, 60, 20, 50, 10, 40, 5], [35, 15, 45, 25, 55, 3, 33, 63], [13, 43, 23, 53, 8, 38, 18, 48], [28, 58, 1, 31, 61, 11, 41, 21], [51, 6, 36, 16, 46, 26, 56, 4], [34, 14, 44, 24, 54, 19, 49, 9], [39, 29, 59, 12, 42, 2, 32, 63], [7, 37, 22, 52, 27, 57, 17, 47]. In some embodiments, the algorithm may separate the data into 8 bursts of data comprising 8 bits each such that the bursts of data are formed together a bit at a time (i.e. burst 0 receives a bit, burst 1 receives a bit, burst 2 receives a bit, etc.) until all of the bursts are filled. As shown, burst 0 may comprise bits 0, 30, 60, 20, 50, 10, 40, and 5. Burst 1 may comprise bits 35, 15, 45, 25, 55, 3, 33, and 63. Burst 2 may comprise bits 13, 43, 23, 53, 8, 38, 18, and 48. Burst 3 may comprise bits 28, 58, 1, 31, 61, 11, 41, and 21. Burst 4 may comprise bits 51, 6, 36, 16, 46, 26, 56, and 4. Burst 5 may comprise bits 34, 14, 44, 24, 54, 19, 49, and 9. Burst 6 may comprise bits 39, 29, 59, 12, 42, 2, 32, and 63. Burst 7 may comprise bits 7, 37, 22, 52, 27, 57, 17, and 47. As previously explained, instead of filling the bursts together one bit at a time as described by the interleaving algorithm, some embodiments of the invention may complete and transmit burst 0, then complete and transmit burst 1, etc., until all of the bursts have been completed and transmitted. Accordingly, less memory is required to buffer (temporarily store) 8 bits of data assigned to one burst as opposed to buffering approximately 64 bits of data as would be required if the data is distributed to burst 0 through burst 7 in an alternating bit to burst allocation scheme (i.e. burst 0 receives a bit, burst 1 receives a bit, burst 2 receives a bit, etc.) FIG. 3 illustrates a table of parameters that may be used to implement the interleaver/de-interleaver 101 of FIG. 2. Specifically, FIG. 3 illustrates a set of general parameters that may be used to implement a variety of interleaving/de-interleaving algorithms (i.e. techniques) using the interleaver/de-interleaver 101. As shown, the parameters may comprise an initial vector (“VI”), an initial vector selection control (“VI_sel”), a delta (offset) vector (“VD”), an ACS initial value (“ACS_VI”), an ACS update rate, an adjust value (“Subtract_V”), a select line (“B0”) for a VD multiplexer, another select line (“B1”) for the VD multiplexer, a select line (“B2”) for multiplexer 108, a number of address pointers value (“N_addr_ptr”), and a burst/code of blocks index calculation (“bst/cdbk index calculation”). Additionally, the table of FIG. 3 also includes a “notes” section that is used to describe aspects of the interleaving/de-interleaving process. The VI parameter may be input to initial value selector 102. As previously described the initial vector may be a vector of variable length. Additionally, VI may comprise a plurality of vectors. As shown in FIG. 3, the VI for interleaving may comprise (0, 98, 82, 66) while the VI for de-interleaving may comprise four vectors: (0, 228), (57, 285), (114, 342), (171, 399). In at least some embodiments, only one vector is used at a time. For example, the vector (0, 228) may be used to assemble a burst “0” from one or more different code blocks (“CDBKs”). Specifically, the vector (0, 228) may be used to assemble burst “0” for CDBKs “0” and “−1.” Based on the VI parameter, the system 101 may output a number of addresses based on code block pointers (“CDBK_ptr”) plus an offset value. For example, if the vector (0, 228) is used as the VI parameter for burst “0,” the system 101 may output the address locations for burst “0” as: CDBK0_ptr+0, CDBK1_ptr+228, CDBK0_ptr+64, CDBK1_ptr+292, CDBK0_ptr+128, etc. In the address locations described above, an offset of 64 is added to the start locations “0” and “228” for the CDBL0 and CDBK1 addresses respectively. This process of adding 64 to an address in continued (for this particular algorithm) until the first burst is assembled. Once the first burst is assembled, the second VI vector (57, 285) may be used for the next burst and so on. This process is repeated. For this particular algorithm, eight bursts are assembled (after four bursts the CDBKs used are CDBK 1 and CDBK 0). The VI_SEL parameter may be input to the initial value selector 102 as a control signal (e.g. signal 122) that permits the initial value selector 102 to select one of the VI values. As shown in FIG. 3, VI_SEL may comprise a signal “K[B1B0]” (interleaving) or “J[B0]” (de-interleaving) that correspond to bit 1 “B1” and/or bit 0 “B0” values taken from a linear index counter J or K. As previously described, either K or J may be a linear index which may then be interleaved/de-interleaved. For example, in at least some embodiments K[B1B0] may follow a repeated two-bit pattern 00, 01, 10, 11 (i.e. a repeated 0, 1, 2, 3 pattern) for interleaving and J[B0] may follow a repeated one-bit pattern 0, 1 for de-interleaving. The signals K[B1B0] and/or J[B0] may correspond to control signal 122 shown in FIGS. 1 and 2. The VD parameter may be input to the offset selector 104. As previously described VD may be a vector of variable length. The ACS_VI parameter may be input to the ACSs 144 shown in FIG. 2. The ACS_VI provides the ACSs 144 with an initial value. As shown in FIG. 3, the ACS_VI may comprise “0” for both interleaving and de-interleaving. The ACS update rate may control the ACSs 144 shown in FIG. 2. In some embodiments, the ACS update rate controls how often an accumulator of each ACS 144 updates the VD value (described above). As shown in FIG. 3, the ACS update rate may be “¼” (i.e., the ACSs 144 are updated every four cycles) for interleaving and “½” (i.e., every two cycles) for de-interleaving. More specifically, if system 100 is used for de-interleaving, the ACSs 144 of offset selector 104 may start with an ACS initial value (ACS_VI) of “0” as previously described. If VD=64, and the ACS update rate=½ as previously described, the pattern followed by the output of the ACSs 144 would be 0, 0, 64, 64, 128, 128, etc. The value stored by each ACS 144 may be added to or subtracted from the selected offset value. Eventually the offset value used by the ACSs 144 may force the index value to go beyond a desired index boundary. Accordingly, the adjust value (“SUB_V”) may be used to compensate for such situations. The SUB_V parameter may be input to the ACSs 144 and the boundary regulator 114 shown in FIG. 2 to adjust the index value such that the index value is moved to within a desired boundary. As shown FIG. 3, SUB_V may equal “114” for interleaving and “456” for de-interleaving. For example, if the index boundaries are [0:455] as illustrated in algorithm 301 (shown in FIG. 3), and the system 101 is used for de-interleaving then the amount of 456 may be subtracted from an index value whenever that index value is greater than 455. “B0” (e.g. a multiplexer select line control) may be input to offset selector 104 as a control line. Accordingly, the offset selector 104 may select a VD value according to B0. As shown in FIG. 3, B0 may equal a K[B2] value, where K[B2] is the second bit taken from a linear index K. Specifically, B0 may comprise a repeated 00001111 pattern for interleaving and constant “0” for de-interleaving. “B1” (e.g. a multiplexer select line control) also may be input to offset selector 104 as a control line. As shown in FIG. 3, B1 may equal “0” for both interleaving and de-interleaving. B0 and B1 may used to select the “VD” parameters illustrated of FIG. 2. The parameter B2 (e.g. a multiplexer select line control) may be input to multiplexing logic 108 as a control line. Therefore, the multplexing logic 108 may select which ACS value to forward to computation block 110 according to B2. In some embodiments, B2 may equal “0” for both interleaving and de-interleaving. In such embodiments, only one of the ACS block is used. However in other embodiments interleaving algorithms may be more complicated and thus require more sophisticated control of multiplexing logic 108. Additionally, some embodiments may utilize additional (more than two) ACSs 144. In at least some embodiments, the B2 value may comprise multiple bits for each clock cycle. For example, FIG. 7D illustrates an embodiment in which B2 comprises two bits. The number of address pointers (“NUM_ADDR_PTR”) parameter may be used by system 100 when implementing bursts as previously described. As shown in FIG. 3, NUM_ADDR_PTR may equal eight for de-interleaving (i.e. one block of code is assembled from 8 bursts). Additionally, NUM_ADDR_PTR may equal two for interleaving (i.e. one burst is assembled from two blocks of code). NUM_ADDR_PTR may be input to controller 112, offset adjuster 106, and/or address calculator 116 in order to assemble bursts and blocks of code. BST/CDBK index calculation may be performed in the controller 112 and output to the address calculator 116 such that the index locations of bursts and blocks of code may be determined. As shown in FIG. 3, the BST/CDBK index calculation may be equal to K[B2B1B0] (i.e. MOD(K,8)) for an interleaver and N−MOD(J,2)+FLOOR(BST_IDX/4) for a de-interleaver. In the function “N−MOD(J,2)+FLOOR(BST_IDX/4)”, BST_IDX corresponds to burst indices 0, 1, 2, 3, 4, 5, 6, and 7, N corresponds to the index of a block of code, MOD corresponds to a modulus function where “MOD(J, 2)”=J−2*FLOOR(J/2), and FLOOR corresponds to rounding to the next lowest integer. The parameters illustrated in FIG. 3 may be used for many different interleaving/de-interleaving algorithms as will later be described. By using the parameter values shown in the table of FIG. 3, the system 101 may interleaving or de-interleaving (reverse interleaving) according to the algorithm 301. The algorithm 301 may be found in section 3.1.3 of the GSM 05.03 V8.5.0 release 1999 standard. By changing and/or programming the parameter values, the system 101 may function as an interleaver/de-interleaver for many different algorithms. These algorithms may be found in standards such as GSM/GPRS/EDGE, WCDMA, and IS2000. FIGS. 4A-4B illustrate a software implementation of an interleaving/de-interleaving algorithm. As shown in FIG. 4A, the algorithm 401 found in section 3.1.3 of the GSM 05.03 V8.5.0 release 1999 standard may be implemented. The FIG. 4A illustrates an embodiment of “hardware code” 403 which illustrates the functionality of the interleaver/de-interleaver 101. FIG. 4B illustrates hardware code related to several interleaving/de-interleaving patterns illustrated in columns 0-7 of Table 1 of the GSM 3.1.3 standard. FIGS. 5A-5S illustrate tables of parameters and parameter values that may be used to implement interleaving and/or de-interleaving algorithms found in the GSM 05.03 V8.5.0 release 1999 standard using the interleaver/de-interleaver 101 of FIG. 2. Specifically, the parameters and parameter values permit system 101 to execute interleaving and/or de-interleaving as described by various tables and algorithms found in the GSM 05.03 V8.5.0 release 1999 standard. In particular, the system 101 may implement MCS-5 EDGE interleaving/de-interleaving algorithms (e.g., as shown in FIGS. 5K and 5L) without using the large look-up table provided by the GSM standard. Specifically, the GSM standard provided the look-up tables for certain algorithms due to a lack of a closed-form description for the interleaving algorithm. Accordingly, embodiments of the invention may implement closed-form versions of these GSM algorithms using the hardware and parameters described previously for FIGS. 1 and 2. While embodiments of the invention may be used to implement interleaving algorithms found, for example, in industry standards such as the GSM 05.03 V8.5.0 release 1999 standard, the invention is not limited to any particular standard. FIGS. 6A and 6B illustrate an interleaving algorithm according to a WCDMA (Wideband Code Division Multiple Access) standard found in the 3GPP TS 25.212-v.3.5.0 (2000-12) release 1999 standard. FIGS. 6C-6D illustrate a table of parameters and parameter values that may be used with the system 101 to implement the algorithm illustrated in FIGS. 6A and 6B. FIGS. 6E and 6F illustrate a 30×30 look up table (LUT) that may be used by the system 101 to provide a de-pruning adjustment when implementing the WCDMA standard illustrated in FIGS. 6A and 6B. Specifically, the LUT contains adjustment values that may be used by the boundary regulator 114 to adjust the combined initial value and offset value such that the extraneous (dummy) bits (referred to in FIG. 6B) are automatically “pruned” without using extra logic and/or waiting cycles. FIGS. 7A-7E illustrate tables of parameters and parameter values that may be used to implement a number of interleaving and/or de-interleaving algorithms found in the IS2000 standard, referenced in 3GPP2 C.S0002-C VERSION 1.0. FIG. 8 illustrates an embodiment of an apparatus 190 that may implement the interleaving/de-interleaving systems 100 and/or 101 shown in FIGS. 1 and 2. As shown in FIG. 8, the apparatus 190 may comprise processing unit 192 coupled to a memory 194 and a transceiver 196, wherein the transceiver implement the interleaver/de-interleaver 101. The apparatus 190 may be representative of a cell phone, personal digital assistance, laptop computer, or any other device that may use interleaving/de-interleaving when communicating. Additionally, embodiments of the invention may be implemented with any transmitter and/or receiver of a communication system. FIG. 9 illustrates a method 900 for interleaving/de-interleaving a block of data in accordance with embodiments of the invention. As shown in FIG. 9, the method 900 may comprise receiving an initial value (block 902) and receiving an offset value (block 904). As previously explained, the initial value and offset values may be selected from one or more vectors. Alternatively, the initial value and/or offset value may be generated as previously described. If the offset needs to be adjusted as determined at block 906, the offset may be adjusted accordingly (block 908), then combined with the initial value (block 910). As described above, the offset may be adjusted to account for bursts and/or bit pruning. If the offset does not need to be adjusted as determined at block 906, the unadjusted offset value is combined with the initial value (block 910). At block 912, a determination is made as to whether the combined initial value and offset is within a pre-determined boundary (e.g. an index boundary). If the combined value is not within the pre-determined boundary as determined at block 912, the combined value may be adjusted so that it is moved to within the pre-determined boundary (block 914). The adjusted combined value may then be output as an index value (block 916). If the combined value is determined to be within the pre-determined boundary (block 912), the combined value may be output as an index value (block 916). As described above, the output index value may be used by an address calculator or other hardware or software functions to interleave and/or de-interleave a block of data. While the preferred embodiments of the present invention have been shown and described, modifications thereof can be made by one skilled in the art without departing from the spirit and teachings of the invention. For example, some embodiments may implement other existing interleaving algorithms that were not mentioned, or future interleaving standards. The embodiments described herein are exemplary only, and are not intended to be limiting. Many variations and modifications of the invention disclosed herein are possible and are within the scope of the invention. Accordingly, the scope of protection is not limited by the description set out above. Each and every claim is incorporated into the specification as an embodiment of the present invention. | <SOH> BACKGROUND <EOH>In wireless communication systems, block interleaving may be used to combat channel fading. Generally, interleaving re-orders bits of information to achieve time diversity of an original sequence of bits (i.e., interleaving changes the order of at least some bits in an original sequence with respect to time). When a transmitted interleaved signal is received, de-interleaving may be used to re-order the transmitted sequence back to the original sequence. A variety of interleaving schemes exist in different wireless standards. Even in the same standard, there may still be a variety of coding schemes that use different interleaving algorithms. For example, the GSM/GPRS/EDGE standard has more than 15 different interleaving algorithms, including various look-up tables (LUTs). Interleaving algorithms may vary in block size (i.e., the amount of bits in an index), level of interleaving, use of bit pruning, and other considerations as will later be described. Most interleaver/de-interleaver implementations may typically be tailored for use with a specified algorithm and may not easily be used with other algorithms. Being able to implement a plurality of different algorithms with one hardware and/or software solution is desirable. Furthermore, finding a multi-standard interleaving solution that does not require large amounts of memory and/or complex hardware is desirable. | <SOH> SUMMARY <EOH>An interleaver/de-interleaver that may be used for multiple interleaving algorithms and look up tables (LUTs) of one or more interleaving standards. In at least some embodiments, the interleaver/de-interleaver may comprise an initial value selector, offset selector, and a pruning adjuster coupled to a combining block. The interleaver/de-interleaver may further comprise a boundary regulator coupled to the combining block, wherein the boundary regulator is configurable to modify an output of the combining block according to one or more pre-determined rules. The interleaver/de-interleaver may further comprise a controller coupled to, at least, the initial value selector, the offset value selector, and the pruning adjuster, whereby the interleaver/de-interleaver may interleave or de-interleave in accordance with a plurality of interleaving/de-interleaving techniques. | 20040115 | 20080701 | 20050721 | 94506.0 | 0 | WILLIAMS, HOWARD L | UNIFIED INTERLEAVER/DE-INTERLEAVER | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,758,745 | ACCEPTED | Ceramic on metal pressure transducer | A transducer apparatus is disclosed herein, including a method thereof for forming the transducer apparatus. A metal diaphragm can be molecularly bonded to a ceramic material to form a ceramic surface thereof. A bridge circuit is connected to the ceramic surface of the metal diaphragm. An input pressure port for pressure sensing thereof can then be provided, wherein the input pressure port is connected to the metal diaphragm to thereby form a transducer apparatus comprising the metal diaphragm, the bridge circuit and the input pressure port. The metal diaphragm is preferably welded to the input pressure. The metal diaphragm and the ceramic surface thereof preferably operate over a temperature of range of at least 40° C. to 150° C., as does the transducer apparatus. The transducer apparatus functions as a pressure transducer that can be used in corrosive media and high temperature applications | 1. A transducer apparatus, comprising: a metal diaphragm molecularly bonded to a ceramic material to form a ceramic surface thereof; a bridge circuit connected to said ceramic surface of said metal diaphragm; an input pressure port for pressure sensing thereof, wherein said input pressure port is connected to said metal diaphragm to thereby form a transducer apparatus comprising said metal diaphragm, said bridge circuit and said input pressure port. 2. The apparatus of claim 1 wherein said metal diaphragm is welded to said input pressure port. 3. The apparatus of claim 1 wherein said metal diaphragm and said ceramic surface thereof operate over a temperature of range of at least 40° C. to 150° C. 4. The apparatus of claim 1 wherein said ceramic material is molecularly bonded to said metal diaphragm to form said ceramic surface thereof. 5. The apparatus of claim 1 wherein said ceramic surface bonded to said metal diaphragm comprises a ceramic substrate. 6. The apparatus of claim 5 wherein said ceramic substrate bonded to said metal diaphragm provides corrosion protection to said metal diaphragm. 7. The apparatus of claim 1 wherein said bridge circuit comprises a resistor network. 8. The apparatus of claim 1 wherein an electrical circuit is formed from a flex circuit board comprising an ASIC and associated circuitry thereof. 9. The apparatus of claim 8 further comprising EMI circuitry which forms part of said flex circuit 10. A transducer apparatus, comprising: a metal diaphragm molecularly bonded to a ceramic substrate, wherein said metal diaphragm and said ceramic substrate operate over a temperature of range of at least 40° C. to 150° C. a bridge circuit bonded to said ceramic substrate of said metal diaphragm to provide corrosion protection to said metal diaphragm; EMI circuitry configured on said flex circuit; an input pressure port for pressure sensing thereof, wherein said input pressure port is welded to said metal diaphragm to thereby form a transducer apparatus comprising said metal diaphragm, said ceramic substrate said bridge circuit and said input pressure port. 11. A method for forming a transducer, comprising the steps of: molecularly bonding a metal diaphragm to a ceramic material to form a ceramic surface thereof; connecting a bridge circuit to said ceramic surface of said metal diaphragm; and providing an input pressure port for pressure sensing thereof, wherein said input pressure port is connected to said metal diaphragm to thereby form a transducer apparatus comprising said metal diaphragm, said bridge circuit and said input pressure port. 12. The method of claim 11 wherein the step of connecting a bridge circuit to said ceramic surface of said metal diaphragm, further comprises the step of: welding said metal diaphragm to said input pressure port. 13. The method of claim 11 wherein said metal diaphragm and said ceramic surface thereof operate over a temperature of range of at least 40° C. to 150° C. 14. The method of claim 11 wherein the step of connecting a bridge circuit to said ceramic surface of said metal diaphragm, further comprises the step of: molecularly bonding said ceramic material to said metal diaphragm to form said ceramic surface thereof. 15. The method of claim 11 wherein said ceramic surface bonded to said metal diaphragm comprises a ceramic substrate. 16. The method of claim 15 wherein said ceramic substrate bonded to said metal diaphragm provides corrosion protection to said metal diaphragm. 17. The method of claim 11 wherein said flex circuit comprises an ASIC (Application Specific Integrated Circuit). 18. The method of claim 17 further comprising the step of forming said ASIC from a flex circuit. 19. The method of claim 18 further comprising the steps: providing a Z-axis conductor; and forming a conductor path from said bridge circuit, through said z-axis conductor into said flex circuit. 20. The method of claim 11 further comprising the step of providing a housing in which said transducer apparatus, including said bridge circuit, said metal diaphragm, said ceramic surface and said input pressure port are located. | TECHNICAL FIELD Embodiments are generally related to sensing devices and methods thereof. Embodiments are also related to pressure transducers. Embodiments are additionally related to pressure sensors. Embodiments are additionally related to ceramic-on-metal and ATF (Advanced Thick Film) processes and techniques. BACKGROUND OF THE INVENTION Various sensors are known in the pressure sensing arts. Pressure transducers are well known in the art. One example of a pressure transducer is a device formed with a silicon substrate and an epitaxial layer, which is grown on the substrate. A portion of the substrate can then be removed, leaving a thin, flexible diaphragm portion. Sensing components can be located in the diaphragm portion to form a pressure transducer. In operation, at least one surface of the diaphragm can be exposed to a process pressure. The diaphragm deflects according to the magnitude of the pressure, and this deflection bends the attached sensing components. Bending of the diaphragm creates a change in the resistance value of the sensing components, which can be reflected as a change in the output voltage signal of a resistive bridge formed at least partially by the sensing components. Some techniques for forming a composite diaphragm for a pressure transducer or similar device involve configuring a substrate layer having a first conductivity type, wherein the substrate layer includes a first surface. Positive implants can then be deposited in the first surface of the substrate layer, and an epitaxial layer grown on the first surface of the substrate layer so that the positive implants form positive diffusions in the epitaxial layer. An oxide pattern can be then formed on the epitaxial layer, and a top layer deposited over the epitaxial layer and oxide pattern. The substrate layer and positive diffusions of the epitaxial layer can then be etched to form the composite diaphragm. Such a composite diaphragm can therefore be provided for use in a pressure sensor or like device. The diaphragm comprises a first layer of silicon nitride and a second layer attached to the silicon nitride layer and comprising a pressure sensor pattern of silicon material. Pressure transducers of the type which comprise a thin, relatively flexible diaphragm portion of suitable material, such as silicon or ceramic, on which either a selected resistive element or a capacitive plate is printed whereby exposure to a pressure source causes deflection of the diaphragm will cause a change in the resistive value of the resistive element or a change in the spacing of the capacitive plate with a mating capacitive plate and concomitantly a change in capacitance are therefore well known in the art. When used as a low pressure sensor, economical packaging of the transducer in a housing so that an effective seal is obtained while at the same time preventing stress related to the mounting and sealing of the transducer from influencing the output becomes problematic. This is caused, at least in part, by the significant difference in thermal expansion between the material used to form the transducer, e.g., silicon, ceramic or the like, and the housing of plastic or the like. A conventional sealing arrangement involves placement of a ring of sealing material around an inlet pressure port in a housing and mounting the transducer so that the pressure sensitive diaphragm is precisely aligned with the pressure port. This conventional arrangement not only involves stress isolation issues, it also limits flexibility in design choices in defining the location of the transducer within the package. One of the major problems with such pressure transducer devices, including those that utilize diaphragm or diaphragm portion configurations, is that such devices are not reliable in corrosive and high-temperature applications. A need therefore exists for a low-cost high accuracy pressure transducer that can be used in corrosive media and high-temperature applications. BRIEF SUMMARY OF THE INVENTION The following summary of the invention is provided to facilitate an understanding of some of the innovative features unique to the present invention and is not intended to be a full description. A full appreciation of the various aspects of the invention can be gained by taking the entire specification, claims, drawings, and abstract as a whole. It is, therefore, one aspect of the present invention is to provide an apparatus and a method which overcomes the above noted prior art limitations. It another aspect of the present invention to provide an improved sensor apparatus and method. It is an additional aspect of the present invention to provide for an improved transducer apparatus. It is yet an additional aspect of the present invention to provide for an improved transducer apparatus, which can be formed utilizing ceramic-on-metal and ATF (Advanced Thick Film) processes and techniques. It is a further aspect of the present invention to provide for an improved method for connecting the flex circuit to the bridge circuit. The aforementioned aspects of the invention and other objectives and advantages can now be achieved as described herein. A transducer apparatus is disclosed herein, including a method thereof for forming the transducer apparatus. A metal diaphragm is molecularly bonded to a ceramic material to form a ceramic surface thereof. A bridge circuit is connected to the ceramic surface of the metal diaphragm. An input pressure port for pressure sensing thereof can then be provided, wherein the input pressure port is connected to the metal diaphragm to thereby form a transducer apparatus comprising the metal diaphragm, the bridge circuit and the input pressure port. The metal diaphragm is preferably welded to the input pressure port. The metal diaphragm and the ceramic surface thereof preferably operate over a temperature of range of at least approximately −40° C. to 150° C., as does the transducer apparatus. The ceramic material is molecularly bonded to the metal diaphragm to form the ceramic surface thereof. The ceramic surface bonded to the metal diaphragm can also be configured as a ceramic substrate. The ceramic surface provides corrosion protection to the metal diaphragm. The bridge circuit generally comprises a resistor network and provides an output proportional to the applied force. A flex circuit comprising an ASIC (Application Specific Integrated Circuit), associated circuitry and EMI protection provides signal conditioning, calibration and compensation. A snap on connector system comprising a plastic snap on lead frame and Z axis conductor material can be utilized for connecting the flex circuit to the bridge network which is located on the diaphragm. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying figures, in which like reference numerals refer to identical or functionally-similar elements throughout the separate views and which are incorporated in and form a part of the specification, further illustrate the present invention and, together with the detailed description of the invention, serve to explain the principles of the present invention. FIG. 1 illustrates a top and side-sectional view of a transducer apparatus, which can be implemented in accordance with a preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION The particular values and configurations discussed in these non-limiting examples can be varied and are cited merely to illustrate at least one embodiment of the present invention and are not intended to limit the scope of the invention. FIG. 1 illustrates a side-sectional view a transducer apparatus 100, which can be implemented in accordance with a preferred embodiment of the present invention. Transducer apparatus generally includes a metal diaphragm 119 which is molecularly bonded to a ceramic material or ceramic substrate 118. A bridge circuit 115 comprising a resistor network can be bonded to the ceramic substrate 118, which is formed on the metal diaphragm 119. A flex circuit 112 comprises an ASIC, EMI protection and associated circuit components. The ceramic substrate 118 is bonded to the metal diaphragm and provides corrosion protection to the metal diaphragm 119. The flex strip 112 connects the bridge circuit 115 to a case or housing 108 (e.g., a cover) and a connector portion 106. The flex circuit can be electrically and mechanically attached to the bridge circuit by catching the flex circuit 112 and z-axis conductor 128 with a plastic lead frame 127 which snaps around the and holds the z axis conductor and flex circuit in place. The components can be aligned such that the conductor path is from the bridge circuit, through the z axis conductor into the flex circuit. Such an assembly method and configuration can therefore eliminate the need for soldering and wire bonding. An input pressure port 122 can be provided for pressure sensing thereof, such that the input pressure port is welded to the metal diaphragm 119 to thereby form the transducer apparatus 100 comprising the metal diaphragm, the ceramic substrate the bridge circuit and the input pressure port. FIG. 1 additionally illustrates welded joint between the pressure port 122 and diaphragm 119. A threaded portion 123 is also depicted in FIG. 1, along with a crimp edge 126, and a connector portion 106. A case or housing 108 surrounds the aforementioned internal components of transducer apparatus 100. Housing 108 can be formed from a suitable material such as plastic a light-weight and non-conducting material. Note that more that one pressure port 122 or connector 106 may be embodied with transducer apparatus 100. Transducer apparatus 100 solves the need for a low-cost and high-accuracy pressure transducer that can be utilized in corrosive media and high-temperature applications. Transducer apparatus 100 can be formed via a ceramic-on-metal technology adapted for use as a pressure sensor design that can be constructed at a low-cost. Processes that are utilized for the formation transducer apparatus 100 include molecular bonding of ceramic to a metal diaphragm, such as, for example, metal diaphragm 119, followed thereafter by welding of the metal diaphragm (i.e., metal diaphragm sensor) to the input pressure port. The ceramic-on-metal design provides high-accuracy and stability over an operating temperature range of approximately 40° C. to 150° C. Ceramic material can be molecularly bonded to the metal diaphragm utilizing an ATF (Advanced Thick Film) process. The metal diaphragm is therefore formed as a ceramic coated article having a metal core (i.e., the metal of the metal diaphragm) and having on at least a portion of the surface of the metal core a coating of a ceramic. The ceramic can be, for example, a glass ceramic, but the use of glass ceramics is not considered a limiting feature of the present invention. Glass ceramic is presented herein only as an example in which the invention can be embodied via the ATF process. A glass ceramic coating can be based on its oxide content and on the total weight of the coating, comprising, for example, (a) from about 8 to about 26% by weight of magnesium oxide (MgO); (b) from about 10 to about 49% by weight of aluminum oxide (Al2O3); and (c) from about 42 to about 68% by weight of silicon oxide (SiO2). Ceramic/glasses adapted for use with the transducer apparatus 100 described herein, generally possess high temperature re-firing capabilities (e.g., 850° C.), and are air fireable. Moreover, ceramic coated article can exhibit a composite thermal coefficient of expansion which is optimum for use in electronic devices, and which can exhibit a low dielectric constant which allows for use with high frequency circuits and allows for greater applicability in electronic application. Furthermore, the ceramic/glasses utilized via the ATF process thereof can exhibit strong adhesion to the metal substrate after firing and are very resistant to thermal stress. This avoids breakdown of the devices formed from the ceramic coated article of this invention when such articles are exposed to high temperatures normally encountered in the operation of electronic devices. This resistance to thermal stress is indeed surprising in view of the relatively large difference in the thermal coefficient of expansion of the metal substrate and the ceramic glass, and the prior teachings that the metal and coating coefficients of expansion must be matched to produce good adhesion. The glass/ceramic coated article thus generally comprises a metal core and possesses on at least a portion of the surface of the metal core a coating of a glass ceramic. A general example of the ATF involves: (a) heating a metal substrate in the presence of oxygen at a first temperature for a time sufficient to form any amount of an oxide layer on the surfaces of the substrate; and (b) applying to all or a portion of the surfaces of the substrate a suspension comprising one or more organic solvents, one or more heat degradable polymeric binders and a calcined mixture of finely divided non-conductive materials comprising (i) from about 8 to about 26% by weight of MgO; (ii) from about 10 to about 49% by weight of Al2O2 and (iii) from about 42 to about 68% by weight of SiO2. Such an ATF process additionally can include (c) heating the coated/metal substrate combination of step (b) at a second temperature for a time sufficient to remove substantially all of the solvents from the applied suspension; and (d) heating the coated/metal substrate combination of step (c) at a third temperature for a time sufficient to degrade substantially all of the binders in the applied suspension; (c) heating the coated/metal substrate combination of step (d) at a fourth temperature for a time sufficient to sinter the non-conductive material to form a device comprising a metal substrate having a predetermined pattern of glass/ceramic material bonded to one or more surfaces thereof. The material can generally comprise (on an oxide basis): (i) from about 8 to about 26% by weight of MgO; (ii) from about 10 to about 49% by weight of Al2O3; and (iii) from about 42 to about 68% by weight of Si O2; (f) heat treating the device at a fifth temperature for a time sufficient to re-crystallize any residual glass contained in the material to any extent. The ATF process provides for greater selectivity in the application of the glass/ceramic materials to specific sites on a substrate which provides for greater freedom in the manufacture of devices such as the transducer apparatus 100. After processing, in accordance with embodiments disclosed herein, the coating can contain crystallized glass/ceramic, which strongly adheres to the metal core and can be suitable as a substrate for processed induced components. An example of an ATF process is disclosed in U.S. Pat. No. 4,794,048 entitled, “Ceramic Coated Metal Substrates for Electronic Applications,” which issued to Oboodi et al on Dec. 28, 1988, and which is incorporated herein by reference. Another example of an ATF process is disclosed in U.S. Pat. No. 4,997,698 entitled “Ceramic Coated Metal Substrates for Electronic Applications,” which issued to Oboodi et al on Mar. 5, 1991, and which is incorporated herein by reference. The embodiments and examples set forth herein are presented to best explain the present invention and its practical application and to thereby enable those skilled in the art to make and utilize the invention. Those skilled in the art, however, will recognize that the foregoing description and examples have been presented for the purpose of illustration and example only. Other variations and modifications of the present invention will be apparent to those of skill in the art, and it is the intent of the appended claims that such variations and modifications be covered. The description as set forth is not intended to be exhaustive or to limit the scope of the invention. Many modifications and variations are possible in light of the above teaching without departing from the scope of the following claims. It is contemplated that the use of the present invention can involve components having different characteristics. It is intended that the scope of the present invention be defined by the claims appended hereto, giving full cognizance to equivalents in all respects. The embodiments of the invention in which an exclusive property or right is claimed are defined as follows. Having thus described the invention | <SOH> BACKGROUND OF THE INVENTION <EOH>Various sensors are known in the pressure sensing arts. Pressure transducers are well known in the art. One example of a pressure transducer is a device formed with a silicon substrate and an epitaxial layer, which is grown on the substrate. A portion of the substrate can then be removed, leaving a thin, flexible diaphragm portion. Sensing components can be located in the diaphragm portion to form a pressure transducer. In operation, at least one surface of the diaphragm can be exposed to a process pressure. The diaphragm deflects according to the magnitude of the pressure, and this deflection bends the attached sensing components. Bending of the diaphragm creates a change in the resistance value of the sensing components, which can be reflected as a change in the output voltage signal of a resistive bridge formed at least partially by the sensing components. Some techniques for forming a composite diaphragm for a pressure transducer or similar device involve configuring a substrate layer having a first conductivity type, wherein the substrate layer includes a first surface. Positive implants can then be deposited in the first surface of the substrate layer, and an epitaxial layer grown on the first surface of the substrate layer so that the positive implants form positive diffusions in the epitaxial layer. An oxide pattern can be then formed on the epitaxial layer, and a top layer deposited over the epitaxial layer and oxide pattern. The substrate layer and positive diffusions of the epitaxial layer can then be etched to form the composite diaphragm. Such a composite diaphragm can therefore be provided for use in a pressure sensor or like device. The diaphragm comprises a first layer of silicon nitride and a second layer attached to the silicon nitride layer and comprising a pressure sensor pattern of silicon material. Pressure transducers of the type which comprise a thin, relatively flexible diaphragm portion of suitable material, such as silicon or ceramic, on which either a selected resistive element or a capacitive plate is printed whereby exposure to a pressure source causes deflection of the diaphragm will cause a change in the resistive value of the resistive element or a change in the spacing of the capacitive plate with a mating capacitive plate and concomitantly a change in capacitance are therefore well known in the art. When used as a low pressure sensor, economical packaging of the transducer in a housing so that an effective seal is obtained while at the same time preventing stress related to the mounting and sealing of the transducer from influencing the output becomes problematic. This is caused, at least in part, by the significant difference in thermal expansion between the material used to form the transducer, e.g., silicon, ceramic or the like, and the housing of plastic or the like. A conventional sealing arrangement involves placement of a ring of sealing material around an inlet pressure port in a housing and mounting the transducer so that the pressure sensitive diaphragm is precisely aligned with the pressure port. This conventional arrangement not only involves stress isolation issues, it also limits flexibility in design choices in defining the location of the transducer within the package. One of the major problems with such pressure transducer devices, including those that utilize diaphragm or diaphragm portion configurations, is that such devices are not reliable in corrosive and high-temperature applications. A need therefore exists for a low-cost high accuracy pressure transducer that can be used in corrosive media and high-temperature applications. | <SOH> BRIEF SUMMARY OF THE INVENTION <EOH>The following summary of the invention is provided to facilitate an understanding of some of the innovative features unique to the present invention and is not intended to be a full description. A full appreciation of the various aspects of the invention can be gained by taking the entire specification, claims, drawings, and abstract as a whole. It is, therefore, one aspect of the present invention is to provide an apparatus and a method which overcomes the above noted prior art limitations. It another aspect of the present invention to provide an improved sensor apparatus and method. It is an additional aspect of the present invention to provide for an improved transducer apparatus. It is yet an additional aspect of the present invention to provide for an improved transducer apparatus, which can be formed utilizing ceramic-on-metal and ATF (Advanced Thick Film) processes and techniques. It is a further aspect of the present invention to provide for an improved method for connecting the flex circuit to the bridge circuit. The aforementioned aspects of the invention and other objectives and advantages can now be achieved as described herein. A transducer apparatus is disclosed herein, including a method thereof for forming the transducer apparatus. A metal diaphragm is molecularly bonded to a ceramic material to form a ceramic surface thereof. A bridge circuit is connected to the ceramic surface of the metal diaphragm. An input pressure port for pressure sensing thereof can then be provided, wherein the input pressure port is connected to the metal diaphragm to thereby form a transducer apparatus comprising the metal diaphragm, the bridge circuit and the input pressure port. The metal diaphragm is preferably welded to the input pressure port. The metal diaphragm and the ceramic surface thereof preferably operate over a temperature of range of at least approximately −40° C. to 150° C., as does the transducer apparatus. The ceramic material is molecularly bonded to the metal diaphragm to form the ceramic surface thereof. The ceramic surface bonded to the metal diaphragm can also be configured as a ceramic substrate. The ceramic surface provides corrosion protection to the metal diaphragm. The bridge circuit generally comprises a resistor network and provides an output proportional to the applied force. A flex circuit comprising an ASIC (Application Specific Integrated Circuit), associated circuitry and EMI protection provides signal conditioning, calibration and compensation. A snap on connector system comprising a plastic snap on lead frame and Z axis conductor material can be utilized for connecting the flex circuit to the bridge network which is located on the diaphragm. | 20040113 | 20050920 | 20050714 | 67577.0 | 0 | OEN, WILLIAM L | CERAMIC ON METAL PRESSURE TRANSDUCER | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,758,829 | ACCEPTED | Panoramic video system with real-time distortion-free imaging | A panoramic annular lens system (PAL), a unitary video camera and a PC-based software system that unwraps a 360° video image into a seamless, distortion free horizontal image image in real time. The PAL system of the preferred embodiment has a 360° horizontal field of view and a 90° vertical field of view in a 40 mm diameter compact package. The invention is not limited to any particular type of lens system. In fact, there are numerous lens systems for providing a 360° panoramic view. The video camera may be a CCD or CMOS based device having a pixel resolution of either 1280×1024 (high resolution) or 720×480 (NTSC). The unwrapping system is a radiometric ray tracing program carried out using a computer's graphics card capabilities to produce highly efficient regional transformation while minimizing software overhead. The result is real time, high resolution 30 fps conversion from a spherical distorted image to a flat panoramic image in Cartesian coordinates. | 1. A method of providing a real-time panoramic video image in a rectangular format; the method comprising the steps of: a) providing a panoramic annular lens system to capture a 360′ viewed annular image; b) focusing said 360° viewed annular image on a video camera image plane; c) transferring a data signal output of said camera image plane to a personal computer; d) utilizing said personal computer to unwrap said annular image into a substantially distortion free rectangular image at a rate of at least 30 fps; and e) presenting said rectangular image on a visual display. 2. The method recited in claim 1 wherein in step a) providing said panoramic annular lens system comprises the step of providing a hyperboloidal lens and ellipsoidal mirror. 3. The method recited in claim 1 wherein in step b) providing said video camera comprises the step of providing a CCD image plane. 4. The method recited in claim 1 wherein in step b) providing said video camera comprises the step of providing CMOS image plane. 5. The method recited in claim 1 wherein step d) comprises the steps of utilizing radiometric ray tracing to first convert said annular image to a distorted unwrapped image and then to convert said distorted unwrapped image to an undistorted unwrapped image. 6. The method recited in claim 1 wherein step d) comprises the step of employing a vertex-based transformation using graphics processing units of said personal computer. 7. The method recited in claim 1 wherein step d) comprises the steps of capturing said data signal output; converting said video image from said data signal output; manipulating said converted video image; and rendering said image in Cartesian format. 8. The method recited in claim 1 wherein step d) comprises the step of using at least one graphics card of said personal computer to unwrap said annular image. 9. An apparatus for providing a real-time panoramic video image in a rectangular format; the apparatus comprising: a panoramic annular lens system configured for capturing 360° viewed annular image; a video camera having an image plane for receiving said annular image and generating a corresponding data signal output; a computer receiving said data signal output; a graphics card and at least one software module in said computer for unwrapping said data signal output from an annular image into a substantially undistorted rectangular image at a rate of at least 30 fps; and a visual display for displaying said rectangular image. 10. The apparatus recited in claim 9 wherein said panoramic annular lens system has a hyperboloidal lens and an ellipsoidal mirror. 11. The apparatus recited in claim 9 wherein said video camera has a CCD imaging plane. 12. The apparatus recited in claim 9 wherein said vide camera has a CMOS imaging plane. 13. The apparatus recited in claim 9 wherein said software module has a program for radiometric ray tracing to first convert said annular image to a distorted unwrapped image and then to convert said distorted unwrapped image to an undistorted unwrapped image. 14. The apparatus recited in claim 9 wherein said software module has a program for vertex-based transformation for unwrapping said annular image. 15. The apparatus recited in claim 9 further comprising means for capturing said data signal output; means for converting said video image from said data signal output; means for manipulating said converted video image; and means for rendering said image in a Cartesian format. 16. A panoramic video system having real-time distortion-free imaging; the system comprising: a panoramic optical system having at least one optical element for viewing a 360° field of view and focusing a corresponding image on an image plane; a video camera having a sensing element at said image plane for converting said image into a corresponding video signal; a computer receiving said video signal and having at least one program for configuring a substantially distortion-free rectangular display of said image at a rate of at least 30 fps; and a monitor for presenting said display. 17. The panoramic video system of claim 16 wherein said optical system optical element comprises an annular element and said corresponding image is an annular image of said 360° field of view. 18. The panoramic video system of claim 16 wherein said video camera comprises a CCD sensing element. 19. The panoramic video system of claim 16 wherein said video camera comprises a CMOS sensing element. 20. The panoramic video system of claim 16 wherein said video camera sensing element has a pixel resolution of at least 1280×1024. 21. The panoramic video system of claim 16 wherein said video camera sensing element has a pixel resolution of at least 720×480. 22. The panoramic video system of claim 16, said computer comprising at least one graphics card for configuring said rectangular display. | CROSS-REFERENCE TO RELATED APPLICATIONS The present invention takes priority from provisional application Ser. No. 60/485,336 filed on Jul. 3, 2003. ORIGIN OF THE INVENTION The invention described herein was made in the performance of work under a USMC contract No. M67854-03-C-1006, and is subject to the provisions of public law 96-517 (35 USC 202) in which the contractor has elected to retain title. FIELD OF THE INVENTION The present invention relates generally to the field of special video camera systems and more specifically to a real-time 360° panoramic video system which utilizes a panoramic annular mirror, video camera and unique unwrapping software which provides a seamless, distortion-free horizontal view of the panoramic image. BACKGROUND OF THE INVENTION Panoramic optical systems which can be employed to provide a 360° field of view, are known. By way of example, U.S. Pat. No. 6,459,451 discloses a catadioptric lens which provides a 360° field of view. Such optical systems can be used advantageously with a camera to provide a system capable of imaging an entire 360° field such as an entire room or landscape from a unitary location using a single camera without requiring scanning or stitching multiple images. However, such lenses provide an image which is not readily interpretable by observers unless the image is first “unwrapped”. The image of a 360° field of view lens is annular or doughnut-shaped and is therefore distorted and not readily discernible by a human observer. It is therefore necessary to convert that image or “unwrap” it into a relatively two-dimensional format such as a horizontal view on a relatively flat medium such as physically on film or electronically on a computer screen. The unwrapping process consists of a mathematical transformation such as by conversion of each picture element or pixel and is preferably accomplished in a manner which results in little or no distortion which would otherwise reduce the quality of the resulting flat image. Such pixel-by-pixel transformations are typically very complex and require complicated and time consuming computer programs, especially for reasonable levels of resolution and images having large numbers of pixels. Consequently, it has not been possible heretofore to exploit panoramic lens technology to provide a real-time unwrapped video image with acceptable resolution. A system which could provide real-time unwrapped video images derived from a panoramic lens and video camera would be highly advantageous for a variety of useful applications. By way of example, such a system could provide security surveillance over a continuous all-around field of view using a unitary display with just one observer. Such a system could also be mounted on a transport mechanism and used for military or police reconnaissance purposes or for robotic imaging. It could also be used for medical visualization and for traffic awareness systems. It can be tailored to be compatible with internet transmission, wireless systems and can be designed for video image compression to reduce transmission bandwidth requirements. Once it becomes convenient to “unwrap” a panoramic video image in real time with little or no distortion and with an acceptable level of resolution, a host of useful and advantageous applications become feasible and readily available. SUMMARY OF THE INVENTION The present invention in its preferred embodiment combines a panoramic annular lens system (PAL), a unitary video camera and a PC-based software system that unwraps a 360° video image into a seamless, distortion free horizontal image image in real time. The PAL system comprises two mirrors, namely, a hyperboloidal mirror and an ellipsoidal mirror interconnected by a 360° circular refracting front or entrance aperture lens and having a rear or exit aperture adjacent a collector lens. The PAL system of the preferred embodiment has a 360° horizontal field of view and a 90° vertical field of view in a 40 mm diameter compact package. The invention is not limited to any particular type of lens system. In fact, there are numerous lens systems for providing a 360° panoramic view. The video camera may be a CCD or CMOS based device having a pixel resolution of either 1280×1024 (high resolution) or 720×480 (NTSC). The unwrapping system is a radiometric ray tracing program carried out using a computer's graphics card capabilities to produce highly efficient regional transformation while minimizing software overhead. The result is real time, high resolution 30 fps conversion from a spherical distorted image to a flat panoramic image in Cartesian coordinates. A graphic user interface (GUI) permits selection of any breaking point (any center line of the panoramic image) as well as zoom in and zoom out capability and built-in calibration. BRIEF DESCRIPTION OF THE DRAWINGS The various embodiments, features and advances of the present invention will be understood more completely hereinafter as a result of a detailed description thereof in which reference will be made to the following drawings: FIG. 1 is a schematic diagram of a panoramic annular lens structure which may be employed in the present invention; FIG. 2, comprising FIGS. 2a and 2b, shows photographic top and side views, respectively of the lens structure of FIG. 1; FIG. 3 is a photographic view of the lens structure of FIG. 1 shown integrated with a CCD camera; FIG. 4, comprising FIGS. 4a and 4b, is a photographic illustration of a PAL image before and after clipping, respectively; FIG. 5 is a photographic representation of the unwrapped version of the PAL image of FIGS. 4a and 4b; FIG. 6, comprising FIGS. 6a, 6b, 6c and 6d, provides photographic views of the image of FIGS. 4a and 4b in wrapped form in two different camera resolutions and in unwrapped form in the same two resolutions, respectively; FIG. 7 is a schematic diagram of an alternative embodiment of a catadioptric omnidirectional ultra-wide-angle camera; FIG. 8 is a simplified illustration of panoramic stereo imaging using a double parabolic mirror; FIG. 9 is a schematic diagram showing the design of a multilevel parabolic mirror and camera; FIG. 10 is a schematic diagram of panoramic imaging using a convex reflecting mirror; FIG. 11 is a schematic diagram of panoramic camera system useful for day and night operation; FIG. 12 is a schematic diagram of an annular flat mirror used in the system of FIG. 11; FIG. 13 is a schematic diagram of panoramic imager having a second medium wavelength infrared optical channel; FIG. 14 is a schematic diagram of the hemisphereic view circular projection of a circular fisheye lens; FIG. 15 is a geometric diagram of a spherical coordinate mapping of the circular fisheye lens; FIG. 16, comprising FIGS. 16a and 16b, is a geometrical representation of spherical and angular mapping, respectively; FIG. 17, comprising FIGS. 17a and 17b, is a photographic view of the original and converted images, respectively, of a circular fisheye lens; FIG. 18 is a computer screen representation of the graphic user interface for real-time conversion (“unwrapping”) software of the preferred embodiment of the invention; FIG. 19 is a computer screen representation of an image captured by a fisheye video camera system in full frame at 30 fps; FIG. 20 is a 1500×1000 Cartesian computer screen image converted at 30 fps from the fisheye image of FIG. 19 using the “unwrapping” software of the present invention; FIG. 21 is a computer screen representation similar to that of FIG. 19 but showing the effect of various calibration methods for reducing distortion; FIG. 22 is a graphical representation of radiometric ray tracing from an input plane to an output plane for a pixel block; FIG. 23, comprising FIGS. 23a, 23b and 23c, is a graphical representation showing transformation process from an annular image to an undistorted rectangular image; FIG. 24 is a block diagram of software flow of real-time unwrapping used in the present invention; FIGS. 25 and 26 are schematic diagrams used to explain the use of panoramic imagers as rangefinders; and FIGS. 27 and 28 are schematic diagrams used to explain the addition of zoom function to a panoramic imager. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Panoramic Annular Lens (PAL) The PAL lens is based on both reflection and refraction of light and offers panoramic 360° field of view in an ultra compact packaging of only 40 mm diameter. The PAL lens provides a vertical field of view such as −40° to +50°. As shown in FIG. 1, the panoramic lens is a piece of glass that consists of a 360° circular aperture (R1), a rear aperture (R2) connecting to a collector lens, a top mirror (H) and a circular mirror (E). The viewpoint of the “virtual camera” is at the plane (O) of the ellipsoidal mirror (E). With this geometry, the PAL sensor can view the entire 360° scene around its vertical axis BC. The vertical field of view is determined by the effective sizes and the locations of the circular mirror E and the top mirror H. Usually the viewing angle is 90° vertically. The PAL is shown in FIGS. 2a and 2b. To maintain wide camera angle options, the PAL mounting is terminated with a C-type mount that fits most ⅓ in. and ½ in. pick-up devices, including CMOS and CCDs. Selection of a pick-up device is important because it defines the final image quality. The most important characteristic is resolution, which should be on the order of 1000 pixels per video line. Progressive mode pick-up devices are preferred because they eliminate temporal video field disparity. A wide range of such devices is available on the market, with the prices dropping as more market share goes to HDTV camcorders such as the JVC GR-HD1, which can record video in 720p HD format (1024×720 pixels in progressive scans at 30 fps). The PAL integrated with a camera is shown in FIG. 3. The image produced by the PAL lens is circularly symmetric, as seen in FIG. 4a. The PAL lens maps all the space within a 360° azimuth and 90° elevation into an annular ring image. The image can still be recognized, and it has relatively low geometric distortion compared to other panoramic visualization systems such as hyperbolic mirror-based 360° systems. The major advantage of the PAL is that it keeps vertical lines straight, significantly reducing the computational complexity of image unwrapping. Only part of the image in FIG. 4a can usefully be unwrapped, as seen in FIG. 4b. The center and outer edges of 4a do not carry any useful visual information, and are discarded. We maintain maximum resolution covering the entire annular ring image by optimizing the relay lens between the PAL and the camera. The unwrapped image unfolded to panoramic Cartesian coordinates is shown in FIG. 5. The PAL assembly was extensively tested on several cameras with a variety of pixel resolutions. We started with a standard NTSC camera, which thus had 420×240 pixels per field. Next we tested the lens with progressive scan cameras, one at 480×480 pixels and one at 1024×1024. For each PAL-camera combination we unwrapped the image and normalized it to the reference camera resolution by bicubic scaling. FIG. 6 compares the images. FIG. 6a shows the image captured by the 1024×1024 pixel camera. FIG. 6b shows a 480×480 pixel image. The corresponding unwrapped images are shown in FIG. 6c for 1024×1024 pixels and in FIG. 6d for 480×480. A detail of both images (a picture on the wall) is magnified in both cases. As expected, close examination of the detail from both images shows smoother edges and better color rendering for the high-resolution image. Catadioptric Ultra-Wide-Angle Camera with Parabolic Mirror In an alternative panoramic vision approach, a catadioptric system creates omnidirectional vision by means of a parabolic mirror. The catadioptric omnidirectional ultra-wide-angle camera (CUWAC) consists of a miniature digital videocamera mounted in a frame and aimed directly at the apex of a parabolic mirror enclosed within a transparent hemisphere, as illustrated in FIG. 7. The dioptric camera lens in FIG. 7 images the focus of the parabola onto a CCD imager. This camera views in all directions within a hemisphere via a parabolic mirror. A CCD camera with a dioptric imaging lens faces the mirror a few inches away and produces a circular image of the reflection. This resulting circular image can then be converted into a normal view in any direction. However, the image quality varies a great deal across the field-of-view; the system magnification is greater at the center of the image and gradually decreases as the image height Y increases. This causes severe image degradation at the field-of-view margins. To overcome this drawback, we extended the panoramic imaging concept to two concentric parabolic mirrors that differ in curvature. In the two-mirror system illustrated in FIG. 8, the axes of the mirrors are collinear, and coincide with the optical axis of the dioptric camera. Each of the mirrors has a profile radially symmetric around this axis. The major parabolic mirror causes less demagnification, and captures those parts of the hemisphere at larger angles with better resolution. The minor mirror has a higher curvature and higher magnification, and captures the central parts of the scene, i.e., close to the optical axis. The CUWAC parabolic optics ensure that it has a single effective center of projection, a single point through which all rays from a scene must pass on their way to the camera lens. That design mimics a camera that takes in only linear perspective, and allows the CUWAC computer software to generate linear perspective images that are free of distortion. Two cameras with fisheye lenses or parabolic mirrors mounted back-to-back can produce views of 360°, a complete sphere, for surveillance or security operations. In teleconferences, such a panoramic camera can show simultaneously every participant seated around a table, in either hemispheric or linear perspective. It will allow a mobile robot to view hemispheric scenes. Placed atop a concert stage or above midfield during a sports event, the ultra-wide angle camera could provide a 360° view—an entire sphere—to viewers. With a joystick or mouse, the viewers could bring any view to their screens, and see not only hemispheric perspective but normal, undistorted, linear perspective. The basic design of this multilevel parabolic mirror is shown in FIG. 9. The projection center C of the hyperbolic mirror coincides with focal point F. The perspective camera is modeled by an internal camera calibration matrix K, which relates 3D coordinates X=[x,y,z]T to retinal coordinates q=[qu,qv,1]T q = 1 z K X . ( 1 ) Analysis of Panoramic Imaging System Research in remotely operated and autonomous systems has shown the usefulness of imaging that can span a very wide field-of-view. If instead of a small conic view, a camera can capture almost an entire hemisphere of visual information (“view-sphere”) at a time, the imaging system gains several advantages. First, it is not necessary to move the camera to fixate on an object of interest, or to perform exploratory camera movements. Second, processing global images of an environment or target scene is less likely to be affected by regions of the image that contain poor information. Third, a wide field-of-view eases the search for reference objects, as they do not disappear from the field-of-view; it helps stabilize image processing algorithms tracking such features. Fourth, a wide field-of-view makes it easier to distinguish image artifacts due to rotation of the camera from image artifacts due to object translation. The ability to view and image an environment panoramically is useful in applications ranging over machine vision, surveillance, collision avoidance, computation of ego-motion, simple and easy detection of objects moving in the environment, and robotics. Reflective optics is cost effective and robust for global imaging. A camera placed below a convex reflecting surface can observe large fields-of-view (see FIG. 10). The mirror profile can be designed for angular gain to extend the camera viewing geometry. With an appropriately shaped mirror, cameras that typically have visual fields-of-view of ˜30° can now image a full 360° in azimuth θ, and up to +120° in elevation φ. FIG. 10 illustrates how a ray reflecting off the reflector surface is directed into the camera viewing cone. Such an imaging device has obvious advantages: first, being a passive sensor it has minimal power requirements. Second, it has the potential to be extremely robust, since the sensor is purely solid state and has no moving parts. Third, curved mirrors can be made relatively free of the optical distortion that is typical of lenses. Cameras with convex mirrors can acquire imagery instantly at video rates; they can be compact, and can cost relatively little to produce. Commercial “fisheye” lenses tend to be much more costly and bulkier than mirrors. In addition, camera optics based on convex mirrors can have well defined mathematical relationships that can be coded into the image processing and data filtering to map the curved geometry of the view-sphere onto the 2D planar pixel array. There are no simple and cost effective purely optical means for correcting the image deformation that occurs in going from a 3D representation to a 2D representation. A fundamental difficulty with panoramic imaging using a curved reflective surface is that image resolution depends on position within the image. In images from standard spherical convex reflectors, resolution depends upon elevation. Visual patches at high elevations are quite different in resolution from those near the horizontal, because they capture smaller solid angles of visual space than do equatorial patches. Designing the mirror profiles to be equiangular, transforms a curved image into a cylindrical projection, preserving a linear relationship between the angle of incidence of light onto the mirror surface and the angle of reflection into the camera with respect to the center of the detector array. This ensures that the camera maintains uniform resolution of the environment in the vertical plane independent of elevation angle, which is very important to high quality panoramic imaging. Left unaccounted for in both mirror design and image processing, vertical nonuniformity causes poor resolution across a given target scene. POC Panoramic Imager for Day/Night Operation FIG. 11 illustrates a modular visible/infrared camera system. Light from the scene is incident on a hyperbolic mirror. The surface profile of this mirror (i.e., conic constant, radius of curvature, and aperture size) is designed in such a way that the focus of the hyperbolic curve acts as the camera projection center, where all rays appear to intersect. Alignment of the mirror with the cameras in this system is critical to maintain the linear relationship between the elevation and camera viewing angles. Those rays satisfying the single viewpoint relationship are reflected by the hyperbolic mirror surface, and are incident on an annular flat mirror (see FIG. 12) that is oriented at 45° with respect to the nadir. Half of the light hitting the annular mirror passes through the clear aperture (lower elevations of the viewing geometry) within the central portion of the mirror, and half the light (higher elevations of the viewing geometry) is reflected at 90°. The light propagating along each optical path is collected by a zoom lens. The video zoom lens for this optical system is a commercial off-the-shelf product with a focal length varying from 8 mm to 48 mm, a working distance that ranges from 1.2 m to ∞, and compatibility with ½ in. format detectors, and has F numbers that range from F1.2-16 and angular fields-of-view from 44.6° to 8°. The two zoom lenses enable us to independently adjust each arm of the sensor. They need not be set to the same zoom magnification (i.e., the blur spot size can be set to fill up the pixel array); this can improve the resolution in each portion of the visual image, which has the benefit of enabling the system to equalize resolution as a function of viewing elevation for the panoramic imager. The minimum blur spot size for the panoramic imager with this zoom lens is estimated to be ˜1.5 to 2 times the diffraction limit. The light from each zoom lens is imaged onto a commercially available 3 megapixel, ½ in. format, CMOS silicon detector chip. The number of pixels in each detector array is 2048×1520, with a 7 μm linear pitch. The larger pixel size improves the low light sensitivity of the camera chip to ˜0.05 lux with reduced fixed pattern noise. According to the manufacturer's specifications, the SNR for this camera is 78 dB. The camera operates in noninterlaced mode (progressive scan), and produces full frame readouts at video rates of 30 frames per second. Full asynchronous image capture with programmable partial scan (region-of-interest mode of operation) gives these cameras the flexibility for numerous daytime/nighttime applications. Both color and monochrome versions of the camera are available. In the color version the overall resolution is reduced by the Bayer color filter; the resolution is about ⅓ for each of the primary colors. Because silicon is sensitive into the near infrared region (700 nm to 1100 nm) of the spectrum, the imager can be used for nighttime surveillance. Moreover, the panoramic imager is designed to be modular so that a second channel can easily be introduced to extend the nighttime vision capability into the mid-wave infrared (3 to 10 μm) region. This design is envisioned with a flat mirror, coated for >98% reflectivity over the MWIR spectrum. The 45° orientation of the flat mirror directs the light toward a second optical channel (see FIG. 13). The rest of the optical layout would be similar to that described previously, with the addition of PtSi or HgCdTe detectors and infrared zoom lens assemblies to detect the infrared scene. Note that these infrared focal plane arrays are only QVGA scale (320×240 pixels), with a linear pitch of 12 μm, so overall resolution would be reduced. However, a multicolor panoramic imager could track targets under conditions that would be beyond the capabilities of the silicon-based detectors. At night infrared irradiance is about two orders of magnitude greater than that in the visible spectrum under moonlight conditions. Additionally one may apply sophisticated image interpolation techniques to increase the image resolution. Mathematical Foundation for Panoramic Image Unwrapping The circular fisheye lens projects a hemispheric view of the surroundings into a circular image as shown in FIG. 14. The panoramic image is a 180° fisheye projection. The projected panoramic image covers a full 180° horizontally, but because of cropping of the frame it covers substantially less vertically, ˜135°. In constructing the unwrapping process, the unit assigned to the limiting circle of the 180° fisheye projection is radius, and its center is chosen as the image origin. Points in the image are assigned polar coordinates (r,θ) and converted to spherical coordinates with angular coordinates θ and φ, where θ is longitude and φ is the angle from the axis of projection as in Eq. (2). FIG. 15 geometrically illustrates the spherical mapping of a circular fisheye image. The transformation from polar to spherical coordinates keeps θ the same and transforms r into φ. FIG. 16 shows the angles of mapping coordinates (FIG. 16a) and a geometrical representation of angular coordinate conversion (FIG. 16b). ( x b y b z b ) = ( cos α 0 sin αsin β cos β - sin αcos β sin β ) ( x d y d ) + ( sin β - sin αcos β cos αcos β ) ( 2 ) Then we can map the hemicube to the fisheye image, and from this we can convert a 180° fisheye image (see FIG. 17a) into a normal perspective image, with the result shown in FIG. 17b. The mapping equations used for transformations of coordinates are: ( ϕ b φ b ) = ( arctan ( y x ) arctan ( x b 2 + y b 2 z ) ) ( 3 ) ( x v y v ) = ( r v cos θ r v sin θ ) ( 4 ) ( θ v r v ) = ( ϕ b r φ b ) ( 5 ) The mapping pipelines the following steps for continuous operation of incoming images: 1. Image plane to angular coordinate 2. Angular coordinate to spherical coordinate 3. Find inverse transformation ( x d , y d ) → ( α , β ) ( x b , y b , z b ) -> ( ϕ b , φ b ) → r ( θ v , r v ) -> ( x v , y v ) ( 6 ) Some of the necessary equations involve spherical coordinates. The angles θ and φ in the following equations are related to a canonical Cartesian (x,y,z) coordinate frame by: x=r·sin (δ)·cos (θ) (7) y=r·sin (δ)·sin (θ) (8) z=r·cos (θ), (9) and their inverse: r2=x2+y2+z2 (10) cos (θ)=x/√{square root over (x2+y2)} (11) sin (θ)=y/√{square root over (x2+y2)} (12) cos (φ)=z/r (13) sin (φ)=√{square root over (x2+y2)}/r. (14) Real-Time Panoramic Video Conversion Software This section discusses the fundamentals of video mapping software architecture and design issues. The conversion system is coded and debugged based on Microsoft Windows Video technology and additional video manipulating software architecture. The performance and stability of the software have been optimized for real-time video conversion software. Designs and Functionalities of Video Mapping Software The preferred embodiment of the invention comprises real-time panoramic video conversion software to convert video from circular polar coordinates to Cartesian panoramic video with 2000×1000 video resolution at 30 frames per second. The real-time panoramic conversion software has been developed in Microsoft Direct3D and DirectShow. Microsoft Direct3D has full capabilities for rendering and mapping images in real time. Direct3D can directly access and manipulate video memory without calling upon operating system services, so the graphics can be manipulated in hardware. The following lists summarize the capabilities of Direct3D. Direct3D functionality Device-dependent access to 3D video-display hardware in a device-independent manner Support for 3D z-buffers Switchable depth buffering Transformation and clipping Access to image-stretching hardware Exclusive hardware access Immediate access to the transformation, lighting, and rasterization 3D graphics pipeline Software emulation if hardware acceleration is not available Direct3D Low Level Functionality 3D coordinate systems and geometry Shading techniques Matrices and transformations Vectors and vertices Copying surfaces Page flipping and back buffering Rectangles Direct3D Application Level Functionality Bump mapping Environment mapping Geometry blending Indexed vertex blending Patches Point sprites Procedural pixel shader Procedural vertex shaders Quaternions Spotlights Tweening Vertex blending Volume textures. Microsoft introduced new technology to apply Direct3D to video applications gluelessly for real-time manipulation of video with mapping, blending, textures, and shadings. The following highlights DirectShow technology. Architecture for streaming media High-quality playback of multimedia streams File based Network stream Universal decoding capability Glueless interface with other DirectX technology Automatic detection of hardware acceleration support Common Object Model (COM)-based interface. The real-time video software was developed around the core functions of Microsoft Direct3D and DirectShow, but the innovative and unique architectural and hierarchical development of this software is the first in the multimedia world that can convert and display panoramic video in real time without noticeable latency. Customizing Microsoft Video Mixing Renderer The Video Mixing Renderer (VMR) is a new DirectShow filter, available only for Windows XP Home Edition and XP Professional, replacing both Overlay Mixer and Video Renderer, and adding many new mixing features. In terms of both performance and breadth of features, the VMR represents the new generation in video rendering on the Windows platform. VMR supports the following new features: Real mixing of multiple video streams, taking advantage of the alpha-blending capabilities of Direct3D hardware devices. The ability to plug in your own compositing component to implement effects and transitions between video streams entering the VMR. True windowless rendering. It is no longer necessary to make the video playback window a child of the application window to play video back. The VMR's new windowless rendering mode makes it easy for applications to host video playback within any window without having to forward window messages to the renderer for renderer-specific processing. A new renderless playback mode, in which applications can supply their own allocator component to get access to the decoded video image prior to its being displayed on the screen. Improved support for PCs equipped with multiple monitors. Support for Microsofts new DirectX Video Acceleration architecture. Support for high-quality video playback concurrently in multiple windows. Support for DirectDraw Exclusive Mode. 100% backward compatibility with existing applications. Support for frame stepping and a reliable way to capture the current image being displayed. The capability for applications to easily alpha-blend their own static image data (such as channel logos or UI components) with the video in a smooth flicker-free way. The VMR depends entirely on the graphics processing capabilities of the computer display card; the VMR does not blend or render any video on the host processor, as doing so would greatly impact the frame rate and quality of the video being displayed. The new features offered by the VMR, particularly blending of multiple video streams and/or application images, depend strongly on the capabilities of the graphics card. Graphics cards that perform well with the VMR have the following hardware support built in: Support for YUV and “non-power of 2” Direct3D texture surfaces. The capability to StretchBIt from YUV to RGB DirectDraw surfaces. At least 16 MB of video memory if multiple video streams are to be blended. The actual amount of memory required depends on the image size of the video streams and resolution of the display mode. Support for an RGB overlay or the capability to blend to a YUV overlay surface. Hardware accelerated video decoding (support for DirectX Acceleration). High pixel fill rates. In our conversion software, we specifically customized VMR renderless mode to maximize the capability and flexibility of the software to better manipulate the controlling parameters. VMR renderless mode features a customized allocator for the customized rendering surface, and a customized renderer for the customized rendering mode. In renderless playback mode, the application Manages the playback window. Allocates the DirectDraw object and the final frame buffer. Notifies the rest of the playback system of the DirectDraw object being used. “Presents” the frame buffer at the correct time. Handles all resolution modes, monitor changes, and “surface losses”—advising the rest of the playback system of these events. The VMR Handles all timing related to presenting the video frame. Supplies quality control information to the application and the rest of the playback system. Presents a consistent interface to the upstream components of the playback system, which are not aware that the application is performing the frame buffer allocation and the rendering. Performs any video stream mixing that may be required prior to rendering. Basically, the conversion software calls various functions of VMR and customized DirectX surfaces to make them fit our specific purpose, which is real-time non-linear image transformation with streaming video in progress. We purposely coded this software with VMR-7 for Windows XP only. DirectX 9 with VMR-9 code migration can be made software compatible with other operating systems such as Windows 9x and Windows 2K as well as Windows XP. Real-Time Panoramic Unwrapping Software The real-time conversion software implements Direct3D Immediate Mode with geometrical relationships to convert spherical images to Cartesian images in arbitrary perspective. The world management of Immediate Mode is based on vertices, polygons, and commands that control them. It allows immediate access to the transformation, lighting, and rasterization 3D graphics pipeline. Image conversion is applied to primitives so that there is no intervening overhead from other interfaces and direct access hardware functions. We tested our software with Nvidia GeForce, ATI Radeon, and Intel low-profile VGA chips. The final code is compatible with most video acceleration chips and processors, so it can be used with major hardware platforms. FIG. 18 shows the graphic user interface (GUI) for the conversion software. FIG. 19 shows fisheye video in the GUI. FIG. 20 shows the corresponding panoramic video converted from the spherical fisheye image in real time (on the fly) at the full 30 frames/second. The unwrapping algorithm may be optimized to alleviate distortion near frame edges. FIG. 21 shows enhanced functions of the player. The following list summarizes the player capabilities and functions: Universal playback capability (MPEG, AVI, and more) Bitmap capture (right-button click) Calibration by clicking three points on a circle (shows circle in red) Adjustments of aspect ratio for non-square pixel digitizers Change center of view in 360° panoramic viewing mode Zoom, pan, and tilt F1 and F2 for zoom-in and -out Arrow buttons for pan and tilt Status bar indicates movie size, capture device, playing time, resolution of movie and display, performance, and viewing angles Capture (and DV) device properties. And performance parameters are: Panoramic and 360° view: ˜30 frames/second with anti-aliasing and anisotropic filters 180° view: ˜20 frames/second and up depends on processor and video card with anti-aliasing and anisotropic filters Video resolution—full screen up to 2048×1536 pixels. Radiometric Ray-Tracing (R2T) R2T yields a single-valued mapping of radiometric quantities such as luminance (brightness) from an input plane to an output plane as shown in FIG. 22 for any continuous optical medium. This procedure is illustrated in FIGS. 23a, 23b and 23c, progressing from an annular image (a) to a distorted unwrapped image (b), and then to a corrected unwrapped image (c). Transformation from a distorted (b) panoramic image of a French window into a perfect (c) panoramic image is by R2T, is based on a priori ray-tracing, equivalent to transformation from a curved system of coordinates into the Cartesian coordinate system. To perform this operation in real time, we divide the 120° horizontal viewing area into a large number of pixel blocks, 10×10 or more, and develop a uniform transformation for each block separately. Hardware Acceleration Conventional omni-view systems use an image by image conversion process to generate transformed (or unwrapped) video with or without hardware acceleration. Yet, conventional transformations (of commercial off the shelf software) are done pixel by pixel and require tremendous CPU power to transform the spherical or cylindrical images to Cartesian or plain view images. The Applicant's approach to this problem is to increase the performance many fold (typically about ˜30 times faster than any existing software in current market), and yet retain the quality of images or video. Animation applications require tremendous processing power for manipulating images because they must provide the real time conversions of perspective, zoom level, morphing, rendering, and so on. Many competing video card manufacturers have been developing these 3D animation engines for Video card (or Graphics Processing Unit) with very high performance graphical performance for better games. We have found that using these high-performance features of GPUs or 3D engines makes it possible to achieve real-time performance on omni-view systems for real-time video conversions. The inventive software utilizes vertex based transformation rather than pixel by pixel processing. Each vertex includes coordinates, color, and image plane information for perspectives. Number of vertices for a single image is limited to 65536 because we did not find any quality enhancement for more vertices than 65536. The following Graphics Processing Units' (GPU) internal functions are used for hardware acceleration: Lighting, Geometry Blending, Alpha, Anisotropic filter or linear filters for distortion correction, 3D textures, Cube textures, Clamping, and Vertex and pixel Pipelining. Lighting: provides detailed brightness and optical calibration Geometry and Vertex Blending: increases the realism of transformed image Alpha Blending: provides the character and drawing overlays to primary video Anisotropic filter: increases the quality by minimizing transforming distortion 3D textures: easier for 3D coordinate transformation Cube textures: for perfect transformation on arbitrary perspective Clamping: for out-of-bound image control Vertex and pixel Pipelining: increases image manipulation in many orders of performance. In summary, the actual image manipulation of colors, lines, points, and perspective changes are all done in hardware or in GPU more specifically. Furthermore, video presentation is also done in hardware with no intervention to other functionalities such as 3D manipulation of vertices. The only CPU load is to calculate the vertex coordinate changes according to the governing equations, e.g. transforming spherical coordinates to Cartesian coordinates. Software Flow As shown in FIG. 24, the software comprises four modules: 1) video capturing, 2) image conversion, 3) presenting image as image manipulation module, and 4) rendering image on video surface. The software provides many video capturing features such as DV capture, video capture with any Microsoft ActiveMovie compliances (16 bit), video capture with WDM (windows driver model −32 bit) drivers for video streaming, and third party capture drivers that are recognized by Windows operating system. Video capture module often introduces significant overheads and resources for software. However, providing proper pipelining and buffering avoids those problems. The image conversion module converts incoming bitmaps in pipelined fashion with multithreading (or super pipelining), so that minimum delay is guaranteed during the process. In this module, Microsoft Direct3D and DirectX functions are utilized for image conversions and manipulation of video memory. The image manipulation is done in primitive level rather than in application level, so that we can have maximum level of programmability and flexibility. In addition, the optimization of performance is possible but the coding is extremely tedious because it requires programming in C++, C, and assembly languages. The presentation module is responsible for preparing video, bitmap capture, calibration (feed-backed to image conversion module), and drawing circles or showing performance information on top of video. Finally, the rendering module is heavily dependent on hardware (video engine) and mostly done by using built-in functions of Microsoft DirectShow. This module sends the final image streams to video memory. FIG. 24 illustrates the overall software architecture for our real-time omni-view video software of the presently preferred embodiment. Panoramic Rangefinder Mirror-based panoramic omnidirectional imagers have a blind zone surrounding the vertical axis (see FIG. 25). Consequently, two such imagers can be positioned along the same vertical axis, one above the other, without any mutual obscuration of the fields of view. This use of two such imagers produces a stereo effect and provides an ability to retrieve the distance to an object based upon parallax angle measurement (see FIG. 26). Panoramic Imager with Zoom Mirror-based panoramic imagers form an image in two steps. In the first step the omnidirectional object space is transferred into an imaginary intermedial ring image above the mirror (see image A′ of FIG. 27). In the second step the projection lens transfers the imaginary intermedial image to the real image at the receiver plane (see image A″ of FIG. 27). Zone 0′0 can be used for the direct view of the upper field zone with zoom ability. An additional lens (negative zoom lens of FIG. 28) creates an imaginary image of the upper conical object field at the plane 0′0, of FIG. 28. Then a projection lens fills zone 0″0″, at the receiver plane with the real image of the intermedial image. Having thus disclosed preferred embodiments to illustrate the various unique features of the invention, it will now be apparent that a panoramic video system according to the present invention may be implemented in various ways, some of which are not necessarily described herein. Therefore, the scope hereof is not to be limited to the specific disclosed embodiments, but only by the appended claims and their equivalents. | <SOH> BACKGROUND OF THE INVENTION <EOH>Panoramic optical systems which can be employed to provide a 360° field of view, are known. By way of example, U.S. Pat. No. 6,459,451 discloses a catadioptric lens which provides a 360° field of view. Such optical systems can be used advantageously with a camera to provide a system capable of imaging an entire 360° field such as an entire room or landscape from a unitary location using a single camera without requiring scanning or stitching multiple images. However, such lenses provide an image which is not readily interpretable by observers unless the image is first “unwrapped”. The image of a 360° field of view lens is annular or doughnut-shaped and is therefore distorted and not readily discernible by a human observer. It is therefore necessary to convert that image or “unwrap” it into a relatively two-dimensional format such as a horizontal view on a relatively flat medium such as physically on film or electronically on a computer screen. The unwrapping process consists of a mathematical transformation such as by conversion of each picture element or pixel and is preferably accomplished in a manner which results in little or no distortion which would otherwise reduce the quality of the resulting flat image. Such pixel-by-pixel transformations are typically very complex and require complicated and time consuming computer programs, especially for reasonable levels of resolution and images having large numbers of pixels. Consequently, it has not been possible heretofore to exploit panoramic lens technology to provide a real-time unwrapped video image with acceptable resolution. A system which could provide real-time unwrapped video images derived from a panoramic lens and video camera would be highly advantageous for a variety of useful applications. By way of example, such a system could provide security surveillance over a continuous all-around field of view using a unitary display with just one observer. Such a system could also be mounted on a transport mechanism and used for military or police reconnaissance purposes or for robotic imaging. It could also be used for medical visualization and for traffic awareness systems. It can be tailored to be compatible with internet transmission, wireless systems and can be designed for video image compression to reduce transmission bandwidth requirements. Once it becomes convenient to “unwrap” a panoramic video image in real time with little or no distortion and with an acceptable level of resolution, a host of useful and advantageous applications become feasible and readily available. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention in its preferred embodiment combines a panoramic annular lens system (PAL), a unitary video camera and a PC-based software system that unwraps a 360° video image into a seamless, distortion free horizontal image image in real time. The PAL system comprises two mirrors, namely, a hyperboloidal mirror and an ellipsoidal mirror interconnected by a 360° circular refracting front or entrance aperture lens and having a rear or exit aperture adjacent a collector lens. The PAL system of the preferred embodiment has a 360° horizontal field of view and a 90° vertical field of view in a 40 mm diameter compact package. The invention is not limited to any particular type of lens system. In fact, there are numerous lens systems for providing a 360° panoramic view. The video camera may be a CCD or CMOS based device having a pixel resolution of either 1280×1024 (high resolution) or 720×480 (NTSC). The unwrapping system is a radiometric ray tracing program carried out using a computer's graphics card capabilities to produce highly efficient regional transformation while minimizing software overhead. The result is real time, high resolution 30 fps conversion from a spherical distorted image to a flat panoramic image in Cartesian coordinates. A graphic user interface (GUI) permits selection of any breaking point (any center line of the panoramic image) as well as zoom in and zoom out capability and built-in calibration. | 20040115 | 20080226 | 20060202 | 94817.0 | H04N5225 | 0 | HO, TUAN V | PANORAMIC VIDEO SYSTEM WITH REAL-TIME DISTORTION-FREE IMAGING | SMALL | 0 | ACCEPTED | H04N | 2,004 |
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10,758,865 | ACCEPTED | Distribution of video content using client to host pairing of integrated receivers/decoders | A host receiver and a client receiver are operatively in a direct broadcast satellite system. Program materials received by the host receiver from the direct broadcast satellite system are decrypted by the host receiver. The decrypted program materials are then encrypted at the host receiver using a copy protection key. The copy protection key is encrypted at the host receiver using a host-client pairing key shared between the host receiver and client receiver. The encrypted program materials and the encrypted copy protection key are transferred from the host receiver to the client receiver. The transferred copy protection key is decrypted at the client receiver using the host-client pairing key. The transferred program materials are then decrypted at the client receiver using the decrypted copy protection key. | 1. A method of operatively pairing a host receiver and a client receiver in a broadcast system, comprising: (a) decrypting program materials generated by a service provider and received by the host receiver from the broadcast system; (b) encrypting the decrypted program materials at the host receiver using a copy protection key; (c) encrypting the copy protection key at the host receiver using a host-client pairing key generated by the service provider and shared between the host receiver and client receiver in order to shate the progaram materials between the host receiver and client receiver, wherein the service provider establishes the host-client pairing key for a particular combination of the host and client receivers: (d) transferring the encrypted program materials and the encrypted copy protection key from the host receiver to the client receiver; (e) decrypting the transferred copy protection key at the client receiver using the host-client pairing key; and (f) decrypting the transferred program materials at the client receiver using the decrypted copy protection key. 2. The method of claim 1, wherein the program materials received by the host receiver are decrypted using a media encryption key. 3. The method of claim 1, wherein the host-client pairing key is received by both the host receiver and the client receiver from the broadcast system. 4. The method of claim 3, futher comprising decrypting the host-client pairing key at the host receiver using a receiver key uniquely associated with the host receiver. 5. The method of claim 4, wherein the copy protection key is generated by the host receiver using content information decrypted by the receiver key uniquely associated with the host receiver. 6. The method of claim 5, wherein the content information comprises a content identifier. 7. The method of claim 6, wherein the content identifier is obtained from the program materials. 8. The method of claim 6, wherein the content identifier further comprises copy control information. 9. The method of claim 3, further comprising decrypting the host-client pairing key at the client receiver using a receiver key uniquely associated with the client receiver. 10. An apparatus for operatively pairing a host receiver and a client receiver in a broadcast system, comprising: (a) means for decrypting program materials generated by a service provider and received by the host receiver from the broadcast system; (b) means for encrypting the decrypted program materials at the host receiver using a copy protection key; (c) means for encrypting the copy protection key at the host receiver using a host-client pairing key generated by the service provider and shared between the host receiver and client receiver in order to shate the program materials between the host receiver and client receiver wherein the service provider establishes the host-client pairing key for a particular combination of the host and client receivers; (d) means for transferring the encrypted program materials and the encrypted copy protection key from the host receiver to the client receiver; (e) means for decrypting the transferred copy protection key at the client receiver using the host-client pairing key; and (f) means for decrypting the transferred program materials at the client receiver using the decrypted copy protection key. 11. The apparatus of claim 10, wherein the program materials received by the host receiver are decrypted using a media encryption key. 12. The apparatus of claim 10, wherin the host-client pairing key is received by both the host receiver and the client receiver from the broadcast system. 13. The apparatus of claim 12, further comprising means for decrypting the host-client pairing key at the host receiver using a receiver key uniquely associated with the host receiver. 14. The apparatus of claim 13, wherein the copy protection key is generated by the host receiver using content information decrypted by the receiver key uniquely associated with the host receiver. 15. The apparatus of claim 14, wherein the content information comprises a content identifier. 16. The apparatus of claim 15, wherein the content identifier is obtained from the program materials. 17. The apparutus of claim 16, wherein the content identifier further comprises copy control information. 18. The apparatus of claim 12, further comprising means for decrypting the host-client pairing key at the client receiver using a receiver key uniquely associated with the client receiver. 19-27. (canceled) 28. The method of claim 1, wherein the particular combination of the host and client receivers results in a different host-client pairing key for each pairing of the client receiver with the host receiver. 29. The method of claim 1, wherein the particular combination of the host and client receivers results in the host receiver sharing the host-client pairing key with all client receivers. 30. The apparatus of claim 10, wherein the partcular combination of the host and client receivers results in a different host-client pairing key for each pairing of the client receiver with the host receiver. 31. The apparatus of claim 10, wherein the particular combinaton of the host and client receivers results in the host receiver sharing the host-client pairing key with all client receivers. | CROSS-REFERENCE TO RELATED APPLICATIONS This application is related to the following co-pending and commonly-assigned patent applications, all of which applications are incorporated by reference herein: U.S. patent application Ser. No. 09/620,832, entitled “VIDEO ON DEMAND PAY PER VIEW SERVICES WITH UNMODIFIED CONDITIONAL ACCESS FUNCTIONALITY,” by Raynold M. Kahn, Gregory J. Gagnon, David D. Ha, Peter M. Klauss, Christopher P. Curren, and Thomas H. James, attorney's docket number PD-200055, filed on Jul. 21, 2000; U.S. patent application Ser. No. 09/620,833, entitled “SECURE STORAGE AND REPLAY OF MEDIA PROGRAMS USING A HARD-PAIRED RECEIVER AND STORAGE DEVICE,” by Raynold M. Kahn, Gregory J. Gagnon, David D. Ha, Peter M. Klauss, Christopher P. Curren, and Thomas H. James, attorney's docket number PD-200042, filed on Jul. 21, 2000; U.S. patent application Ser. No. 09/621,476, entitled “SUPER ENCRYPTED STORAGE AND RETRIEVAL OF MEDIA PROGRAMS IN A HARD-PAIRED RECEIVER AND STORAGE DEVICE,” by Raynold M. Kahn, Gregory J. Gagnon, David D. Ha, Peter M. Klauss, Christopher P. Curren, and Thomas H. James, attorney's docket number PD-200043, filed on Jul. 21, 2000; U.S. patent application Ser. No. 09/620,773, entitled “SUPER ENCRYPTED STORAGE AND RETRIEVAL OF MEDIA PROGRAMS WITH MODIFIED CONDITIONAL ACCESS FUNCTIONALITY, ” by Raynold M. Kahn, Gregory J. Gagnon, David D. Ha, Peter M. Klauss, Christopher P. Curren, and Thomas H. James, attorney's docket number PD-20044, filed on Jul. 21, 2000; U.S. patent application Ser. No. 09/620,772, entitled “SUPER ENCRYPTED STORAGE AND RETRIEVAL OF MEDIA PROGRAMS WITH SMARTCARD GENERATED KEYS,” by Raynold M. Kahn, Gregory J. Gagnon, David D. Ha, Peter M. Klauss, Christopher P. Curren, and Thomas H. James, attorney's docket number PD-200045, filed on Jul. 21, 2000; U.S. patent application Ser. No. 09/491,959, entitled “VIRTUAL VIDEO ON DEMAND USING MULTIPLE ENCRYPTED VIDEO SEGMENTS,” by Robert G. Arsenault and Leon J. Stanger, attorney's docket number PD-980208, filed on Jan. 26, 2000; Application Ser. No. 09/960,824, entitled “METHOD AND APPARATUS FOR ENCRYPTING MEDIA PROGRAMS FOR LATER PURCHASE AND VIEWING,” by Raynold M. Kahn, Gregory J. Gagnon, David D. Ha, Peter M. Klauss, Christopher P. Curren, Ronald P. Cocchi, and Thomas H. James, attorney's docket number PD-200176, filed Sep. b 21, 2001; Application Ser. No. 09/954,236, entitled “EMBEDDED BLACKLISTING FOR DIGITAL BROADCAST SYSTEM SECURITY,” by Raynold M. Kahn, Gregory J. Gagnon, David D. Ha, and Dennis R. Flaherty, attorney's docket number PD-200125, filed Sep. 14, 2001; U.S. patent application Ser. No. __/___,___, entitled “METHOD AND APPARATUS FOR ENSURING RECEPTION OF CONDITIONAL ACCESS INFORMATION IN MULTI-TUNER RECEIVERS,” by Peter M. Klauss, Raynold M. Kahn, Gregory J. Gagnon, and David D. Ha, attorney's docket number PD-200183, filed on Nov. b 21, 2002; U.S. patent application Ser. No. __/___,___, entitled “METHOD AND APPARATUS FOR MINIMIZING CONDITIONAL ACCESS INFORMATION OVERHEAD WHILE ENSURING CONDITIONAL ACCESS INFORMATION RECEPTION IN MULTI-TUNER RECEIVERS,” by Peter M. Klauss, Raynold M. Kahn, Gregory J. Gagnon, and David D. Ha, attorney's docket number PD-200184, filed on Nov. 21, 2002; PCT international Patent Application Serial No. US02/29881, entitled “METHOD AND APPARATUS FOR CONTROLLING PAIRED OPERATION OF A CONDITIONAL ACCESS MODULE AND AN INTEGRATED RECEIVER AND DECODER,” by Raynold M. Kahn and Jordan Levy, attorney's docket number PD-200176A PCT, filed on Sep. 20, 2002; U.S. patent application Ser. No. __/___,___, entitled “DISTRIBUTION OF VIDEO CONTENTUSING A TRUSTED NETWORK KEY FOR SHARING CONTENT,” by Raynold M. Kahn, Gregory J. Gagnon, Christopher P. Curren and Thomas H. James, attorney's docket number PD-200290, filed on same date herewith; and U.S. patent application Ser. No. __/___,___, entitled “DISTRIBUTION OF BROADCAST CONTENT FOR REMOTE DECRYPTION AND VIEWING,” by Raynold M. Kahn, Ronald Cocchi and Gregory J. Gagnon, attorney's docket number PD-200292, filed on same date herewith. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to systems and methods for distributing video content using client to host pairing of integrated receivers/decoders (IRDs). 2. Description of the Related Art Direct broadcast satellite (DBS) systems have become commonplace in recent years. DBS have been designed to ensure that only paying subscribers receive program materials transmitted by service providers. Among such systems are those which use a conditional access module (typically in the form of a smartcard) that can be removably inserted into the receiver. One of the disadvantages of existing DBS receivers is that every television requires a separate integrated receiver/decoder (IRD) and conditional access module in order to receive unique programming. Moreover, each of the IRDs requires a tuner and conditional access module in order to receive and decrypt the programming. In addition, each of the IRDs requires a disk drive or other non-volatile storage in order to provide digital video record (DVR) capabilities. All of these components drive up the cost of the IRDs. Currently, there is no method of a host IRD with a conditional access module securely sharing content one or more client IRDs without a conditional access module. One of the key reasons is that the prior art provides no method for the service provider to selectively control authorized client IRDs. Service providers have no method of preventing widespread, and possible unauthorized, distribution of their program materials if several IRDs are networked together. The present invention describes an architecture that includes a central or host IRD and one or more lightweight secondary or client IRDs coupled thereto. The present invention also describes a method of encrypting the program materials between the IRDs in the network and a method for the host IRD to know which other client IRDs are allowed on the network using a host-client relationship. Since these client IRDs are known and trusted by the host IRD, then the host IRD can transmit program materials to the client IRDs. This means that the client IRDs would not require a tuner, conditional access module, or disk drive, since the host IRD is responsible for the reception, descrambling and storage of the program material, and the conditional access module associated with the host IRD is responsible for the reception of media encryption keys for program decryption by host and client IRDs. This allows distribution of the program materials throughout a household or other location at a significantly reduced cost as compared to other schemes, which require full IRDs for each individual subscriber. SUMMARY OF THE INVENTION In summary, the present invention describes a method, apparatus and article of manufacture for operatively pairing a host receiver and a client receiver in a direct broadcast satellite system. Program materials received by the host receiver from the direct broadcast satellite system are decrypted by the host receiver using a media encryption key. The decrypted program materials are then encrypted at the host receiver using a copy protection key. The copy protection key is generated by the host receiver using content information decrypted by a receiver key uniquely associated with the host receiver. The content information may comprise a content identifier obtained from the program materials, and may also include copy control information. The copy protection key is encrypted at the host receiver using a host-client pairing key shared between the host receiver and client receiver. The encrypted program materials and the encrypted copy protection key are then transferred from the host receiver to the client receiver. The transferred copy protection key received by the client receiver from the host receiver is decrypted at the client receiver using the host-client pairing key. The transferred program materials received by the client receiver from the host receiver are then decrypted at the client receiver using the decrypted copy protection key. BRIEF DESCRIPTION OF THE DRAWINGS Referring now to the drawings in which like reference numbers represent corresponding parts throughout: FIG. 1 is a diagram illustrating an overview of a direct broadcast satellite system according to a preferred embodiment of the present invention; FIG. 2 is a block diagram showing a typical uplink configuration for a single satellite transponder, showing how program materials and program control information are uplinked to the satellite by the control center and the uplink center; FIG. 3A is a diagram of a representative data stream according to the preferred embodiment of the present invention; FIG. 3B is a diagram of a representative data packet according to the preferred embodiment of the present invention; FIG. 4 is a simplified block diagram of an integrated receiver/decoder according to the preferred embodiment of the present invention; FIG. 5 is a logical flow illustrating how the host IRD and CAM are operatively paired according to the preferred embodiment of the present invention; FIG. 6 is a logical flow illustrating how the host and client IRDs are operatively paired according to the preferred embodiment of the present invention; and FIG. 7 is a logical flow illustrating how the program materials may be shared between host and client IRDs according to the preferred embodiment of the present invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS In the following description, reference is made to the accompanying drawings which form a part hereof, and which show, by way of illustration, several embodiments of the present invention. It is understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. DIRECT BROADCAST SATELLITE SYSTEM FIG. 1 is a diagram illustrating an overview of a direct broadcast satellite system 100 according to a preferred embodiment of the present invention. The system 100 includes a control center 102 operated by a service provider in communication with an uplink center 104 via a ground link 106 and with subscriber receiving stations 108 via a link 110. The control center 102 provides program materials to the uplink center 104 and coordinates with the subscriber receiving stations 108 to offer various services, including key management for encryption and decryption, pay-per-view (PPV), billing, etc. The uplink center 104 receives the program materials from the control center 102 and, using an uplink antenna 112 and transmitter 114, transmits the program materials to one or more satellites 116, each of which may include one or more transponders 118. The satellites 116 receive and process this program material, and re-transmit the program materials to subscriber receiving stations 108 via downlink 120 using transmitter 118. Subscriber receiving stations 108 receive the program materials from the satellites 116 via an antenna 122, and decrypt and decode the program materials using an integrated receiver/decoder (IRD) 124. UPLINK CONFIGURATION FIG. 2 is a block diagram showing a typical uplink center 104 configuration for a single transponder 118, showing how program materials and program control information are uplinked to the satellite 116 by the control center 102 and the uplink center 104. One or more channels are provided by program sources 200A-200C, which may comprise one or more video channels augmented respectively with one or more audio channels. The data from each program source 200A-200C is provided to a corresponding encoder 202A-202C, which in one embodiment comprise Motion Picture Experts Group (MPEG) encoders, although other encoders can be used as well. After encoding by the encoders 202A-202C, the output therefrom is converted into data packets by corresponding packetizers 204A-204C. In addition to the program sources 200A-200C, data source 206 and conditional access manager 208 may provide one or more data streams for transmission by the system 100. The data from the data source 206 and conditional access manager 208 is provided to a corresponding encoder 202D-202E. After encoding by the encoders 202D-202E, the output therefrom is converted into data packets by corresponding packetizers 204D-204E. A system channel identifier (SCID) generator 210, null packet (NP) generator 212 and system clock 214 provide control information for use in constructing a data stream for transmission by the system 100. Specifically, the packetizers 204A-204F assemble data packets using a system clock reference (SCR) from the system clock 214, a control word (CW) generated by the conditional access manager 208, and a system channel identifier (SCID) from the SCID generator 210 that associates each of the data packets that are broadcast to the subscriber with a program channel. Each of the encoders 202A-202C also accepts a presentation time stamp (PTS) from a multiplex controller 216. The PTS is a wrap-around binary time stamp that is used to assure that the video channels are properly synchronized with the audio channels after encoding and decoding. Finally, these data packets are then multiplexed into a serial data stream by the controller 216. The data stream is then encrypted by an encryption module 218, modulated by a modulator 220, and provided to a transmitter 222, which broadcasts the modulated data stream on a frequency bandwidth to the satellite 116 via the antenna 106. REPRESENTATIVE DATA STREAM FIG. 3A is a diagram of a representative data stream 300 according to the preferred embodiment of the present invention. The first packet 302 comprises information from video channel 1 (data coming from, for example, the first program source 200A); the second packet 304 comprises computer data information that was obtained, for example from the computer data source 206; the third packet 306 comprises information from video channel 3 (from one of the third program source 200C); the fourth packet 308 includes information from video channel 1 (again, from the first program source 200A); the fifth packet 310 includes a null packet (from the NP generator 212); the sixth packet 312 includes information from audio channel 1 (again, from the first program source 200A); the seventh packet 314 includes information from video channel 1 (again, from the first program source 200A); and the eighth packet 316 includes information from video channel 2 (from the second program source 200B). The data stream therefore comprises a series of packets from any one of the program and/or data sources in an order determined by the controller 216. Using the SCID, the IRD 124 reassembles the packets to regenerate the program materials for each of the channels. FIG. 3B is a diagram of a representative data packet 318 according to the preferred embodiment of the present invention. Each data packet segment 318 is 147 bytes long, and comprises a number of packet segments 320-326. The first segment 320 comprises two bytes of information containing the SCID and flags. The SCID is a unique 12-bit number that uniquely identifies the channel associated with the data packet 318. The flags include 4 bits that are used to control whether the data packet 318 is encrypted, and what key must be used to decrypt the data packet 318. The second segment 322 is made up of a 4-bit packet type indicator and a 4 -bit continuity counter. The packet type identifies the packet as one of the four data types (video, audio, data, or null). When combined with the SCID, the packet type determines how the data packet 318 will be used. The continuity counter increments once for each packet type and SCID. The third segment 324 comprises 127 bytes of payload data. The fourth segment 326 is data required to perform forward error correction on the data packet 318. ENCRYPTION OF PROGRAM MATERIALS As noted above, program materials are encrypted by the encryption module 218 before transmission to ensure that they are received and viewed only by authorized IRDs 124. The program materials is encrypted according to an encryption key referred to hereinafter as a control word (CW). This can be accomplished by a variety of data encryption techniques, including symmetric algorithms, such as the data encryption standard (DES), and asymmetric algorithms, such as the Rivest-Shamir-Adleman (RSA) algorithm. To decrypt the program material, the IRD 124 must also have access to the associated CW. To maintain security, the CW is not transmitted to the IRD 124 in plaintext. Instead, the CW is encrypted before transmission to the IRD 124. The encrypted CW is transmitted to the IRD 124 in a control word packet (CWP), i.e., a data packet type as described in FIG. 3B. In one embodiment, the data in the CWP, including the CW, is encrypted and decrypted via what is referred to hereinafter as an input/output (I/O) indecipherable algorithm. An I/O indecipherable algorithm is an algorithm that is applied to an input data stream to produce an output data stream. Although the input data stream uniquely determines the output data stream, the algorithm selected is such that it's characteristics cannot be deciphered from a comparison of even a large number of input and output data streams. The security of this algorithm can be further increased by adding additional functional elements which are non-stationary (that is, they change as a function of time). When such an algorithm is provided with identical input streams, the output stream provided at a given point in time may be different than the output stream provided at another time. So long as the encryption module 218 and the IRD 124 share the same I/O indecipherable algorithm, the IRD 124 can decode the information in the encrypted CWP to retrieve the CW. Then, using the CW, the IRD 124 can decrypt the program materials so that it can be displayed or otherwise presented. INTEGRATED RECEIVER/DECODER FIG. 4 is a simplified block diagram of an IRD 124 according to the preferred embodiment of the present invention. The IRD 124 includes a tuner 400, a transport and demultiplexing module (TDM) 402 that operates under the control of a microcontroller 404 to perform transport, demultiplexing, decryption and encryption functions, a source decoder 406, random access memory (RAM) 408, external interfaces 410, user I/O 412, a conditional access module (CAM) 414, and conditional access verifier (CAV) 416. The tuner 400 receives the data packets from the antenna 122 and provides the packets to the TDM 402. Using the SCIDs associated with the program materials, the TDM 402 and microcontroller 404 reassemble the data packets according to the channel selected by the subscriber and indicated by the user I/O 412, and decrypt the program materials using the CW. Once the program materials have been decrypted, they are provided to the source decoder 406, which decodes the program materials according to MPEG or other standards as appropriate. The decoded program materials may be stored in the RAM 408 or provided to devices coupled to the IRD 124 via the external interfaces 410, wherein the devices coupled to the IRD 124 can include or a media storage device 418, such as a disk drive, a presentation device 420, such as a monitor, or a networked device, such as another IRD 124. The CAM 414 is typically implemented in a smartcard or similar device, which is provided to the subscriber to be inserted into the IRD 124. The CAM 414 interfaces with the CAV 416 and the TDM 402 to verify that the IRD 124 is entitled to access the program materials. The CW is obtained from the CWP using the CAV 416 and the CAM 414. The TDM 402 provides the CWP to the CAM 414 via the CAV 416. The CAM 414 uses the I/O indecipherable algorithm to generate the CW, which is provided back to the TDM 402. The TDM 402 then uses the CW to decrypt the program materials. In one embodiment including a plurality of networked IRDs 124, one of the IRDs 124 is designated a “host IRD” and each of the other IRDs are designated as a “client IRD”. In such an embodiment, the host IRD 124 includes all of the components described in FIG. 4, while the client IRDs 124 are simpler and do not include a tuner 400, CAM 414, CAV 416, disk drive 418, or other components, in order to reduce the cost of the client IRD 124. The client IRD 124 can be used to request program materials that are received or reproduced by the host IRD 124, thus allowing program materials to be reproduced at other locations in the home. However, in this embodiment, the host and client ERDs 124 share a host-client pairing key (HCPK) that is generated by the service provider for the purposes of sharing the program materials among the IRDs 124. Consequently, the HCPK permits distribution of video content between a host IRD 124 and one or more client IRDs 124 using a client-to-host pairing. OPERATIVE PAIRING THE HOST IRD AND CAM FIG. 5 is a logical flow illustrating how the host IRD 124 and CAM 414 are operatively paired according to the preferred embodiment of the present invention. After the subscriber has purchased and installed the host IRD 124 and associated hardware, the subscriber supplies a unique identifier (such as a serial number) for the host IRD 124 to the service provider. The unique identifier is itself uniquely associated with a secret receiver key (RK). This association is implemented in the IRD 124 itself, and is known to the service provider. Thereafter, the service provider determines a pairing key (PK) that will be used to encrypt communications between the CAM 414 and the IRD 124. The PK is then encrypted by the service provider using the RK, to produce an encrypted PK, denoted ER(PK), wherein the ER( ) indicates that RK encryption is used and the PK indicates that the PK is encrypted. A message for the CAM 414 comprising the PK and the ER(PK) is generated by the service provider, and the message is encrypted using a conditional access message encryption algorithm to produce EM(PK, ER(PK)), wherein the EM( ) indicates that conditional access message encryption is used and the PK, ER(PK) indicates that the PK, ER(PK) is encrypted. The EM(PK, ER(PK)) is then transmitted to the IRD 124 where it is received by the tuner 400 and TDM 402. The TDM 402 routes data packets with the encrypted message EM(PK, ER(PK)) to the CAM 414 for decryption. In the CAM 414, the EM(PK,ER(PK)) is decrypted by a message decryption algorithm (EM DECR) 500 to produce the decrypted PK, which is stored in a secure memory 502 in the CAM 414. The ER(PK) is provided from the CAM 414 to the TDM 402, and since it is encrypted using the RK, it is not exposed in plaintext. (In this embodiment, ER(PK) is delivered to the TDM 402 via the CAM 414, but an alternative embodiment might deliver ER(PK) directly to the TDM 402). In the TDM 402, the ER(PK) is decrypted by an Advanced Encryption Standard (AES) decryption algorithm (AES DECR) 504 using the RK 506 to produce the decrypted PK, which is then in a secure memory 508. This PK, now stored in both the IRD 124 and the CAM 414, is used to encrypt communications between the CAM 414 and the IRD 124, as desired. For example, using the PK, the CAM 414 encrypts the CW to produce EPK(CW), wherein the EPK( ) indicates that PK encryption is used and the CW indicates that the CW is encrypted. The TDM 402 decrypts the EPK(CW) received from the CAM 414. Since the EPK(CW) can only be decrypted by an IRD 124 that contains the appropriate PK, this cryptographically binds (“pairs”) the CAM 414 and the IRD 124. OPERATIVELY PAIRING THE HOST AND CLIENT IRDS FIG. 6 is a logical flow illustrating how the host and client IRDs 124 are operatively paired according to the preferred embodiment of the present invention. The present invention also provides for pairing between a host IRD 124 and one or more client IRDs 124, to ensure that program materials are never shared between the host IRD 124 and client IRDs 124 in plaintext. The pairing of the host IRD 124 and client IRDs 124 is accomplished by the use of a host-client pairing key (HCPK). As noted above, the subscriber supplies a unique identifier (such as a serial number) for the host IRD 124 to the service provider, wherein the unique identifier is associated with a secret receiver key (RK), wherein the association is implemented in the IRD 124 itself and is known to the service provider. After activating the host IRD 124, the subscriber can request the activation of additional client IRDs 124 using the same method. Consequently, the service provider would determine the RK for each of the client IRDs 124 as well. Thereafter, the service provider establishes the HCPK for a particular combination of host and client IRDs 124. Preferably, the service provider encrypts the HCPK, using the AES algorithm with RKH, the RK of the host IRD 124, and RKC, the RK of the client IRD 124, thereby creating two ER(HPCK) messages containing the encrypted HCPK, i.e., ERH(HCPK) for the host IRD 124 and ERC(HCPK) for the client IRD 124. The service provider sends one or more messages to the host IRD 124, using an ID for the CAM 414 of the host IRD 124 for over-the-air addressing of the message, and specifying both a Host ID (HID) and a Client ID (CLID), wherein the CLID identifies the client IRDs 124 to the host IRD 124. The message is received by the host IRD 124, and then stored on disk drive 418 or other non-volatile memory in the host IRD 124. A large number of such messages can be stored on the disk drive 418 in the host IRD 124, e.g., one for each client IRD 124 networked with the host IRD 124. Any number of such encrypted versions of the HCPK can be stored in the host, IRD 124. For example, there may be a different HCPK for each pairing of a client IRD 124 networked with the host IRD 124. On the other hand, a host IRD 124 may share the same HCPK with all the client IRDs 124. Preferably, the host IRD 124 receives both of the ERH(HCPK) and ERC(HPCK) messages off-air and, at some later time, the ERC(HCPK) for the client IRD 124 is obtained by the client IRD 124 from the host IRD 124. This may occur, for example, when a client IRD 124 is activated or powered up. In both the host and client IRDs 124, the ER(HCPK) (which is either ERH(HPCK) or ERC(HCPK)) is decrypted by an AES decryption algorithm (AES DECR) 600 in the TDM 402 using the appropriate RK 602 (which is either the RKH or RKC), and the decrypted HCPK is stored in a secure memory 604 in the host and client IRDs 124. Consequently, the service provider, through the assignment of the HCPK, establishes a client-to-host pairing relationship between the host IRD 124 and one or more client IRDs 124 forming a network, so that the program materials are shared in secure manner within the network. SHARING PROGRAM MATERIALS BETWEEN HOST AND CLIENT IRDS FIG. 7 is a logical flow illustrating how the program materials may be shared between host and client IRDs 124 according to the preferred embodiment of the present invention. In the portion of FIG. 7 labeled “Off-Air Receive,” the host IRD 124 receives a data stream including the program materials encrypted by the media encryption key CW, as well as the encrypted media encryption key EI(CW) itself. The EI(CW) is provided, via the TDM 402, to the CAM 414, where it is decrypted by an I/O indecipherable algorithm (EI DECR) 700. The result is the unencrypted media encryption key CW. The unencrypted CW is then re-encrypted by the CAM 414 by an AES encryption algorithm (AES ENCR) 702 using the PK 704 stored in the CAM 414 to produce a re-encrypted media encryption key EPK(CW). The re-encrypted media encryption key EPK(CW) is provided to the TDM 402, where it is decrypted by an AES decryption algorithm (AES DECR) 706 using the PK 708 stored in the TDM 402, in order to obtain the unencrypted media encryption key CW. The unencrypted CW is then stored in a CW storage 710, and used when necessary by a Data Encryption Standard (DES) decryption algorithm (DES DECR) 712 to decrypt the program material. In the portion of FIG. 7 labeled “Save to Disk or Transmit to Client IRD,” the content identification (CID) information 714 is decrypted by an AES decryption algorithm (AES DECR) 716 using the RK 718 stored in the TDM 402, in order to generate a CP session key for encrypting and decrypting the program materials shared with the client IRD 124. The CID information 714 preferably comprises a content identifier that is obtained from properties and/or metadata found in the program materials, and may include copy control information (CCI). After the CP session key is generated by the AES decryption algorithm 716, the CP session key is then stored in the memory 720 of the TDM 402. Thereafter, the CP session key is retrieved from the memory 720 of the TDM 402 for use in encrypting the program materials by a 3DES encryption algorithm (AES ENCR) 722. Since the program materials are encrypted with the CP session key generated by the host IRD 124, the client IRD 124 must be able to receive the CP session key from the host IRD 124 in a secure manner. To accomplish this task, the CP session key is encrypted by an AES encryption algorithm (AES ENCR) 724 using the HCPK 726 stored in the TDM 402, to produce an encrypted CP session key EHCPK(CP). Finally, both the encrypted program materials and the encrypted copy protection key are transferred from the host IRD 124 to the client IRD 124, as represented by 728. In the portion of FIG. 7 labeled “Read from Host IRD and Display,” the client IRD 124 obtains the encrypted CP session key EHCPK(CP) from the host IRD 124, which is then decrypted by an AES decryption algorithm (AES DECR) 730 using the HCPK 732. As noted above, the client IRD 124 had been previously been provided the HCPK 732 by the service provider. After the CP session key is generated by the AES decryption algorithm 730, the CP session key is then stored in the memory 734 of the TDM 402. Thereafter, the CP session key is retrieved from the memory 734 of the TDM 402 for use in decrypting the program materials by the AES decryption algorithm (AES DECR) 736. The client IRD 124 can then display the program materials on a presentation device 420 coupled to the client IRD 124. Consequently, the host IRD 124 can control access to the program materials, by selective encryption of the program materials and CP session key that are then transmitted to appropriate client IRDs 124. The program materials are only encrypted once, by the host IRD 124, and are delivered to the client IRD 124 only in encrypted form, together with the CP session key necessary to decrypt the program materials. One of the advantages to this method is that it allows the host IRD 124 to control which of the client IRDs 124 receives the program materials. This could be an advantage if the service provider wishes to have several tiers of services for the client IRDs 124. This could also allow subscribers to selectively control which program materials are distributed to which client IRD 124 if limits, either rating or spending, are to be set. Also, if a client IRD 124 is suspected of not being in the location indicated or is being used for pirating purposes, the distribution of program materials to that client IRD 124 could be terminated without disrupting services to other client IRDs 124 in the network. The disadvantage of this system would be the number of keys that would be required for each pairing and the bookkeeping of all of these keys. Both of these issues are not serious and could be overcome by careful system planning. As noted above, since this method does not require the client IRD 124 to perform any traditional conditional access tasks, no CAM 414 is required on the client IRD 124. Also, since the client IRD 124 does not need to receive program materials from an off-air signal, no tuner is required in the client IRD 124. Finally, no disk drive 418 is required in the client IRD 124, since client IRDs 124 may use the disk drive 418 of the host IRD 124 as a “virtual” disk. All of this leads to greatly reduced cost of the client IRDs 124. CONCLUSION The foregoing description of the preferred embodiment of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. For example, while the foregoing disclosure presents an embodiment of the present invention as it is applied to a direct broadcast satellite system, the present invention can be applied to any system that uses encryption. Moreover, although the present invention is described in terms of specific encryption and decryption schemes, it could also be applied to other encryption and decryption schemes, or to different uses of the specific encryption and decryption schemes. Finally, although specific hardware, software and logic is described herein, those skilled in the art will recognize that other hardware, software or logic may accomplish the same result, without departing from the scope of the present invention. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto. The above specification, examples and data provide a complete description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to systems and methods for distributing video content using client to host pairing of integrated receivers/decoders (IRDs). 2. Description of the Related Art Direct broadcast satellite (DBS) systems have become commonplace in recent years. DBS have been designed to ensure that only paying subscribers receive program materials transmitted by service providers. Among such systems are those which use a conditional access module (typically in the form of a smartcard) that can be removably inserted into the receiver. One of the disadvantages of existing DBS receivers is that every television requires a separate integrated receiver/decoder (IRD) and conditional access module in order to receive unique programming. Moreover, each of the IRDs requires a tuner and conditional access module in order to receive and decrypt the programming. In addition, each of the IRDs requires a disk drive or other non-volatile storage in order to provide digital video record (DVR) capabilities. All of these components drive up the cost of the IRDs. Currently, there is no method of a host IRD with a conditional access module securely sharing content one or more client IRDs without a conditional access module. One of the key reasons is that the prior art provides no method for the service provider to selectively control authorized client IRDs. Service providers have no method of preventing widespread, and possible unauthorized, distribution of their program materials if several IRDs are networked together. The present invention describes an architecture that includes a central or host IRD and one or more lightweight secondary or client IRDs coupled thereto. The present invention also describes a method of encrypting the program materials between the IRDs in the network and a method for the host IRD to know which other client IRDs are allowed on the network using a host-client relationship. Since these client IRDs are known and trusted by the host IRD, then the host IRD can transmit program materials to the client IRDs. This means that the client IRDs would not require a tuner, conditional access module, or disk drive, since the host IRD is responsible for the reception, descrambling and storage of the program material, and the conditional access module associated with the host IRD is responsible for the reception of media encryption keys for program decryption by host and client IRDs. This allows distribution of the program materials throughout a household or other location at a significantly reduced cost as compared to other schemes, which require full IRDs for each individual subscriber. | <SOH> SUMMARY OF THE INVENTION <EOH>In summary, the present invention describes a method, apparatus and article of manufacture for operatively pairing a host receiver and a client receiver in a direct broadcast satellite system. Program materials received by the host receiver from the direct broadcast satellite system are decrypted by the host receiver using a media encryption key. The decrypted program materials are then encrypted at the host receiver using a copy protection key. The copy protection key is generated by the host receiver using content information decrypted by a receiver key uniquely associated with the host receiver. The content information may comprise a content identifier obtained from the program materials, and may also include copy control information. The copy protection key is encrypted at the host receiver using a host-client pairing key shared between the host receiver and client receiver. The encrypted program materials and the encrypted copy protection key are then transferred from the host receiver to the client receiver. The transferred copy protection key received by the client receiver from the host receiver is decrypted at the client receiver using the host-client pairing key. The transferred program materials received by the client receiver from the host receiver are then decrypted at the client receiver using the decrypted copy protection key. | 20040116 | 20090825 | 20080124 | 94378.0 | H04L900 | 0 | ABRISHAMKAR, KAVEH | DISTRIBUTION OF VIDEO CONTENT USING CLIENT TO HOST PAIRING OF INTEGRATED RECEIVERS/DECODERS | UNDISCOUNTED | 0 | ACCEPTED | H04L | 2,004 |
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10,758,987 | ACCEPTED | Termite tubing preventative for non-wood materials | The present invention relates to materials and methods for protecting man-made structures made with non-wood materials from termite damage through the application of borates to the surface of non-wood materials. In an embodiment the invention regards a method for preventing termite tunneling and tubing on non-wood and/or non-cellulosic materials by treating non-wood building components comprising the steps of applying a composition to the surfaces of a non-wood building component, wherein the composition comprises a borate component. In another embodiment the invention regards a method for preventing termite damage to man-made structures comprising the steps of mixing borates with a solvent to form a borate solution, obtaining a non-wood building component, coating the non-wood building component with the borate solution, and incorporating the coated non-wood building component into a man-made structure. The invention also regards a non-wood building component comprising a non-wood substrate, and a coating comprising borates, wherein the coating is disposed on the surfaces of the non-wood substrate. | 1. A method for preventing termite tunneling and tubing on non-wood and/or non-cellulosic materials by treating non-wood building components comprising the steps of: applying a composition to the surfaces of a non-wood building component; and wherein the composition comprises a borate component. 2. The method of claim 1, wherein the composition is a borate solution comprising glycol, disodium octaborate tetrahydrate, and water, wherein the disodium octaborate tetrahydrate comprises from 10 to 30% of the solution by weight. 3. The method of claim 1, wherein the composition is applied in an amount effective to prevent termites from forming tubes across the surface of the non-wood building component. 4. The method of claim 1, wherein the composition is applied to all external surfaces of the non-wood building component. 5. The method of claim 1, wherein the non-wood building component is cementitious. 6. The method of claim 1, wherein the non-wood building component is a metal. 7. The method of claim 1, wherein the non-wood building component is polymeric. 8. The method of claim 1, wherein the solution does not penetrate throughout the interior of the non-wood building component. 9. The method of claim 1, wherein the composition comprises borates from compounds selected from the group consisting of boric acid, sodium borates, zinc borates, calcium borates, sodium calcium borates, calcium magnesium borates, and organic borates. 10. The method of claim 1, wherein the composition is applied by spraying, dipping, brushing, roller coating, misting, foaming, fogging, powder coating, pressure immersion, or gaseous application. 11. The method of claim 1, wherein applying a composition to the surfaces of a non-wood building component comprises applying a composition to the interior and/or exterior walls of a ready built or partially built structure. 12. The method of claim 1, wherein applying a composition to the surfaces of a non-wood building component comprises applying a composition to cavities of a ready built structure. 13. The method of claim 1, wherein applying a composition to the surfaces of a non-wood building component comprises applying a composition to a concrete slab or to foundation walls of new or existing structures. 14. The method of claim 1, wherein applying a composition to the surfaces of a non-wood building component comprises applying a composition to non-wood materials in and around bath traps or other areas where external utilities are brought into a structure. 15. A method for preventing termite damage to man-made structures comprising the steps of: mixing borates with a solvent to form a borate solution; obtaining a non-wood building component; coating the non-wood building component with the borate solution; incorporating the coated non-wood building component into a man-made structure. 16. The method of claim 15, wherein the coated non-wood building component is incorporated into the man-made structure at that portion between the ground and wood or cellulosic materials, wherein the non-wood building component forms a non-traversable termite barrier. 17. The method of claim 15, wherein the termite damage to be prevented is that caused by Reticulitermes, Heterotermes or Coptotermes. 18. The method of claim 15, wherein the borate solution comprises glycol, disodium octaborate tetrahydrate, and water, wherein the disodium octaborate tetrahydrate comprises from 10 to 30% of the solution by weight. 19. The method of claim 15, wherein the borate solution is applied in an amount effective to prevent termites from forming tubes across the surface of the building component. 20. The method of claim 15, wherein the borate solution is applied to all external surfaces of the building component. 21. The method of claim 15, wherein the building component is cementitious. 22. The method of claim 15, wherein the non-wood building component is a metal. 23. The method of claim 15, wherein the non-wood building component is polymeric. 24. The method of claim 15, wherein the coating on the non-wood building component does not penetrate throughout the interior of the non-wood building component. 25. The method of claim 15, wherein the borates are from compounds selected from the group consisting of boric acid, sodium borates, zinc borates, calcium borates, sodium calcium borates, calcium magnesium borates, silicon borates and organic borates. 26. The method of claim 15, wherein the borate solution is applied by spraying, dipping, brushing, roller coating, pressure immersion, or gaseous application. 27. A non-wood building component comprising: a non-wood substrate; and a coating comprising borates; wherein the coating is disposed on the surfaces of the non-wood substrate. 28. The non-wood building component of claim 27, wherein the coating comprises an amount of borates effective to prevent termites from forming tubes over the surface of the non-wood substrate. 29. The non-wood building component of claim 27, wherein the coating is applied as a solution comprising glycol, disodium octaborate tetrahydrate, and water, wherein the disodium octaborate tetrahydrate comprises from 10 to 30% of the solution by weight. 30. The non-wood building component of claim 27, wherein the borate solution is applied to all accessible surfaces of the non-wood substrate. 31. The non-wood building component of claim 27, wherein the non-wood substrate is cementacious. 32. The non-wood building component of claim 27, wherein the non-wood building component is a metal. 33. The non-wood building component of claim 27, wherein the non-wood building component is polymeric. 34. The non-wood building component of claim 27, wherein the coating on the non-wood substrate does not penetrate throughout the interior of the non-wood substrate. 35. The non-wood building component of claim 27, wherein the borates are from compounds selected from the group consisting of boric acid, sodium borates, zinc borates, calcium borates, sodium calcium borates, calcium magnesium borates, silicon borates, and organic borates, or mixtures there of. 36. The non-wood building component of claim 27, wherein the coating is applied by spraying, misting, fogging, foaming, dipping, brushing, roller coating, pressure immersion, or gaseous application, or by powder coating. 37. The non-wood building component of claim 27, wherein the coating forms a complete or partial barrier between the soil and the rest of the structure that is non traversable by termites. 38. The non-wood building component of claim 27, further comprising a coating of a penetration minimizing agent. | FIELD OF THE INVENTION The present invention relates to materials and methods for protecting man-made structures from termite damage by treating non-wood and/or non-cellulosic materials. More particularly, the present invention relates to the application of borates to the surface of non-wood and/or non-cellulosic materials. BACKGROUND OF THE INVENTION Termites are unique among insects in their ability to derive nutritional benefit from cellulose, which is the component of wood and plants that gives structural rigidity to cells. However, as a result of feeding on wood and cellulose containing products, termites can cause significant damage to man-made structures and the cellulose materials contained within. Generally speaking, subterranean termites must stay in close reach of the soil at all times, lest they die from dehydration. Accordingly, wood touching soil is easily accessed and damaged by termites. However, subterranean termites also can build shelter tubing to travel between the soil and wood that is nearby, but not actually touching the soil. The shelter tubing provides a dark, moist environment that protects the termites from sunlight, predators, or dehydration. Termites may also build shelter tubes through the soil to avoid certain highly repellant termiticides. To prevent termite damage, termite barrier insecticides have been applied to soil under and around dwellings for many years as a chemical barrier. Approaches have included the injection or spray application of large volumes of organic pesticides such as organophosphates and pyrethroids into soil prior to the pouring or construction of building foundations. However, this approach causes environmental concerns as the pesticide goes directly into the environment. Moreover, this approach has performance limitations because the pesticide is lost from the vicinity within a 3 to 10 year period, thereafter allowing termite access. Further, rain during construction or some other form of physical activity (digging, walking, pipe laying etc) breaks the barrier and often leads to premature failure of the insecticide treatment. A different approach to termite control has been to apply borates to wood used in construction through spray or pressure applications to poison the termites' food source. Borates have been used in almost all types of wood end use including the treatment of solid wood, plywood and wood composites. The benefits of borates include efficacy against all wood destroying organisms (fungi, boring beetles & termites), low acute mammalian toxicity and low environmental impact. As an example of this approach, a specific glycol borate formulation containing 40 wt. % disodium octaborate tetrahydrate (DOT) and applied diluted in water to 23 wt. % DOT (available commercially as BORA-CARE®), has been demonstrated and approved in the USA as a stand alone alternative to soil poisoning, when sprayed on all structural wood to a height of two feet in new construction. However, treating only structural wood with borates has practical limitations. One limitation of this approach is that a large percentage of new construction uses building materials other than wood. Brick, block, concrete, steel frame, vinyl, stucco, gypsum, expanded foam and polystyrene board are all common construction materials that can be used in the absence of wood, or with a very low volume of wood. While termites generally don't directly damage non-cellulosic materials such as concrete, termites have the ability to build shelter tubing over these non-wood construction materials and then cause damage to books, paper, wall coverings, wood composite fixtures and fitting, hardwood floors, and other wood or cellulose items. Thus, while it is not effective to treat homes and commercial building constructed in this way by treating only structural wood with borates, subterranean termite protection is still warranted. Another approach to the use of borates has been to incorporate them into building products, including cementitious products. However, this approach has not proven effective as it still allows termite tubing over the building material so the terminates can reach other vulnerable items. This approach has a further limitation in that the application of borates to cementitious products may act as a setting retardant and ultimately affect structural integrity of some building products into which it is incorporated. Therefore, a need exists for an environmentally safer way of protecting man-made structures made with non-wood materials, and the contents therein, from termite damage. SUMMARY OF THE INVENTION In an embodiment the invention regards a method for preventing termite tunneling and tubing on non-wood and/or non-cellulosic materials by treating non-wood building components comprising the steps of applying a composition to the surfaces of a non-wood building component, wherein the composition comprises a borate component. In another embodiment the invention regards a method for preventing termite damage to man-made structures comprising the steps of mixing borates with a solvent to form a borate solution, obtaining a non-wood building component, coating the non-wood building component with the borate solution, and incorporating the coated non-wood building component into a man-made structure. The invention also regards a non-wood building component comprising a non-wood substrate, and a coating comprising borates, wherein the coating is disposed on the surfaces of the non-wood substrate. The above summary of the present invention is not intended to describe each discussed embodiment of the present invention. This is the purpose of the figures and the detailed description that follows. DRAWINGS The invention may be more completely understood in connection with the following drawings, in which: FIG. 1 is a cross-section of a non-wood building component with a borate solution coating. FIG. 2 is an example of termite tubing behavior on a non-wood building component with a borate solution coating and on a non-wood building component without a borate solution coating. While the invention is susceptible to various modifications and alternative forms, specifics thereof have been shown by way of example and drawings, and will be described in detail. It should be understood, however, that the invention is not limited to the particular embodiments described. On the contrary, the intention is to cover modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE INVENTION Where a borate composition is applied to a non-wood substrate in accordance with the invention, termites attempt to form tubes, but there is very rapid termite mortality and therefore a discontinuation of tubing activity on the treated non-wood substrates. In an embodiment the invention regards a method for preventing termite tunneling and tubing on non-wood and/or non-cellulosic materials by treating non-wood building components comprising the steps of applying a composition to the surfaces of a non-wood building component, wherein the composition comprises a borate component. In another embodiment the invention regards a method for preventing termite damage to man-made structures comprising the steps of mixing borates with a solvent to form a borate solution, obtaining a non-wood building component, coating the non-wood building component with the borate solution, and incorporating the coated non-wood building component into a man-made structure. The invention also regards a non-wood building component comprising a non-wood substrate, and a coating comprising borates, wherein the coating is disposed on the surfaces of the non-wood substrate. Materials to be Treated Many different non-wood and/or non-cellulosic materials can be treated with a borate composition in accordance with various embodiments of the invention. For example, in an embodiment, cementitious materials are treated. Cementitious materials are those materials that are made from cement and/or have the properties of cement. Suitable materials for treatment can include brick, block, stone, concrete, stucco, gypsum. Metals can also be treated with a borate composition in accordance with the invention. For example, steel or copper may be treated. Additionally, plastics or polymeric based materials can be treated including expanded foam, PVC, vinyl, polystyrene and other plastics or polymers. One of skill in the art will appreciate that many non-wood and/or non-cellulosic substrates can be treated in accordance with the invention. Materials of varying levels of porosity may be treated in accordance with the invention. In some embodiments, materials with a high level of porosity are treated. In other embodiments, materials that have a less than high level of porosity are treated. Borate Compositions Applied The borate compositions applied may comprise a borate compound as an active agent, a carrier, and a diluent. One of skill in the art will appreciate that the borate compositions applied may also comprise other components including adjunct active agents, solubility enhancers, colorings or dyes, co-diluents, viscosity modifying agents, adhesive components, powders, polymer forming agents, etc. In an embodiment, the borate compositions applied may comprise a dry composition, depending on the nature of building component to be treated. The form of the borate composition may vary depending on the type of material treated, the termite species from which protection is desired, and the ambient climatic conditions. Suitable borate compounds may include those of high or low solubility. Low solubility borate compounds may be used in the form of a suspension, may be treated first to enhance their solubility, or may be used in conjunction with a separate compound that functions to enhance their solubility. Suitable borate compounds may include boric acid, sodium borates such as borax and DOT (disodium octaborate tetrahydrate), zinc borates, calcium borates, sodium calcium borates, calcium magnesium borates, organic borates such as boresters and boronic acids and any mixtures thereof. Suitable carriers may include polyalkylene glycols, including short chain polyalkylene glycols having an average molecular weight of between about 100 and 500. Specific carriers include propylene glycol, monoethylene glycol, diethylene glycol, triethylene glycol and polyethylene glycol. Suitable diluents include polar solvents such as water, alcohols or glycols, with or without the addition of surfactants. Organic solvents such as mineral spirits and kerosene can be used with emmulsifiers or with organic borates such as boresters or boronic acids. Other components such as rheology modifiers, thickening agents and polymerizing film formers such as starch, agar, xanthan gum, gelatin, latex, acrylics, alkyds etc., may also be added. The borate composition, as it is applied, may not work optimally if it comprises too low of a concentration of a borate compound. Therefore, in some embodiments, the borate composition comprises greater than 0.1 wt % of a borate compound. In a particular embodiment, the borate composition comprises between 0.1 wt % and 100.00 wt % of a borate compound. In another embodiment, the borate composition may comprise between about 10.0 wt % and 30.0 wt % of a borate compound. In one embodiment the borate composition comprises glycol, DOT (disodium octaborate tetrahydrate), and water, wherein the DOT ranges from 10.0 wt % to 30.0 wt %. As an example, a solution of glycol, DOT (disodium octaborate tetrahydrate), and water is commercially available, sold as BORA-CARE®, and is available from Nisus Corporation, 100 Nisus Drive, Rockford, Tenn. 37853. Glycols are readily available from a variety of commercial sources. One such source is Dow Chemical. For example, E200 is an ethylene glycol having an average molecular weight of about 200 and a chemical abstract registry number of 25322-68-3 and is available from Dow Chemical. Borate Application The borate solution may be applied by a number of different methods including low pressure spraying, high pressure spraying, brushing, dipping, misting, foaming, fogging, roller coating, spreading, pressure immersion and even gaseous application. Where gaseous application is employed, volatile borates, such as boresters including trimethyl borate, may be used. The specific application technique used may vary with the given material treated. In many embodiments, the borate solution is applied after the building component, or substrate, is already formed, as opposed to mixing the borate solution into the material before the building component is formed. The borate solution may be applied to the interior, and or exterior walls of a ready-built, or partially built, structure. The borate solution may also be applied to cavities of a ready built structure (e.g. cavity wall or within hollow concrete blocks). The borate solution may also be applied to the concrete slab or foundation walls of new or existing structures. The borate solution may be applied in and around bath traps or other areas where external utilities (water pipes, electric conduits, gas pipes etc) are brought into a structure. The total amount of borates to be applied depends on the particular substrate as well as the particular insect species from which protection is sought. A coating without a sufficient amount of borates may not be optimal. In an embodiment, a coating that is greater than 0.005 g/cm2 of a borate solution is applied. However, using more borates than is necessary for sufficient performance may be uneconomical. Therefore, in an embodiment, a coating that is less than 1.0 g/cm2 of a borate solution is applied. In an embodiment, an average coating of from about 0.005 g/cm2 to about 1 g/cm2 of borate solution is applied. In another embodiment, an average coating of from 0.04 g/cm2 to 0.10 g/cm2 of borate solution is applied. In a particular embodiment, an average coating of 0.071 g/cm2 of borate solution is applied. As many non-wood building components are porous, application of a borate composition will lead to some penetration of the solution into the building component. Penetration, in effect, depletes protection by reducing the surface concentration of borates. In many non-porous materials penetration is minimal. Penetration may also be limited in dry porous materials. The depth of penetration will depend on the particulars of the borate composition as well as the given building component including its porosity and moisture content, in addition to the mode of borate application. Generally, borate compositions with higher levels of light organic solvents will penetrate more deeply into a given dry building component. Referring to FIG. 1, a cross-sectional view of a building component 10 is shown that has been treated with a borate composition. The borate composition has been applied to the surface 12 of the building component 10 and has penetrated throughout a penetration zone 14 (not drawn to scale) around the perimeter of the building component 10. The borate composition has penetrated to the edge 16 of the penetration zone, dividing the penetration zone 14 from an exclusionary zone 18 on the interior of the building component. While FIG. 1 shows a penetration zone 14, one of skill in the art will appreciate that at least where a non-porous or only slightly porous building components are used, a penetration zone may not be formed and the borate composition may reside at the surface of the building component. In an embodiment of the invention, the borate composition is a low solubility borate applied in a non-solubilizing and/or highly volatile solvent, in order to limit penetration and maximize the amount of the borate composition available at the surface of the building product. Other methods of limiting borate penetration are also contemplated by the invention. By way of example, a penetration minimizing solution can be applied to the non-wood building component before the borate solution is applied. Such a penetration minimizing solution can act to fill the pores of the non-wood building component such that when the borate solution is later applied it does not filter into the component as deeply. Examples would include wax emulsions, polymer forming agents such as polyvinyl alcohol, silicone, acrylics, alkyds or other sealants such as coating systems or paints. In an embodiment, the invention comprises a coating of a penetration minimizing agent. Insects Embodiments of the invention are effective in preventing damage from subterranean termites including Reticulitermes, Heterotermes, Coptotermes, Microtermes, Nasutitermes, Neotermes and Mastitermes. The invention, in one embodiment, may be effective against Reticulitermes, Heterotermes and Coptotermes termites in particular. In a particular embodiment, the invention can be used to prevent damage caused by Formosan subterranean termites (Coptotermes formosanus). In other embodiments, the invention is used to prevent damage from tube forming insects generally, such as mud daubing wasps. The present invention may be better understood with reference to the following examples. These examples are intended to be representative of specific embodiments of the invention, and are not intended as limiting the scope of the invention. EXAMPLE 1 Application of Borates Concrete decorative columns, 15.2 cm×5 cm×61 cm (6 inches×2 inches×24 inches) with one scalloped edge, were obtained as exemplary non-wood building components. The columns were given a brush treatment with a solution comprising 20 wt. % disodium octaborate tetrahydrate, a glycol carrier, and water on all surfaces of the columns to the point of surface refusal. An average coating of 0.071 g/cm2 of the solution was applied as shown in Table 1. The treatments were cured at room temperature prior to testing. TABLE 1 Treatment Weight Surface Area g/cm2 Column 1 161.05 2274 0.0708 Column 2 161.06 2274 0.0708 Column 3 160.96 2274 0.0708 Column 4 161.33 2274 0.0710 Column 5 162.53 2274 0.0715 EXAMPLE 2 Tubing Test The five treated columns from Example 1 (columns 1-5) were tested against 5 otherwise identical untreated columns (columns 6-10). The test also included a southern yellow pine control to determine general termite activity. Each concrete column was placed on edge to provide a column that extended 58.4 cm (23 inches) above the sand surface. Each column was placed in 1500 grams of autoclaved blasting sand containing 300 grams of distilled water. A piece of southern yellow pine sapwood was placed on top of each column. Formosan subterranean termites (Coptotermes formosanus) were collected by a bait crate method from Brechtel State Park in Louisiana. These are recognized as the most voracious, most damaging and most difficult to control of the subterranean termites. Two thousand Formosan subterranean termites (determined by weight from sampling) were placed on the sand in the pan. This structure was placed in a larger pan to create a moat to keep the termites from escaping. Each setup was covered by plastic bags to maintain high humidity. The southern yellow pine controls were used to determine health and quality of the termites. Where applicable, testing followed the standard as described in American Wood-Preservers' Association Standard E1-97. All tests were maintained in a conditioned room at 27° C. An initial test for a concrete control (Column #7) was set up to determine if the termites would tunnel on the concrete. After 4 days a tunnel had been constructed 16 inches above the sand level. The southern yellow pine controls were set up and run for 28 days. The visual rating for the controls was based on the following rating system: 10—Sound, surface nibbles permitted; 9—Light attack; 7-Moderate attack, penetration; 4-Heavy attack; 0—Failure. EXAMPLE 3 Effectiveness in Preventing Tubing The concrete column test was run for 30 days. The columns were initially checked daily with the length of any tubing present and the number of termites found in the surrounding water noted. The results for the tubing activity are shown in Table 2. In these tables, treated columns are numbered 1-5 and the untreated columns numbered 6-10. The tubing activity was measured every day for the first 18 days. It was found that termites built tubes the entire length of the column in only 1 to 7 days for the untreated columns, once tubing started. Termites on the borate treated columns reacted differently. The Formosan subterranean termites in these setups were not able to produce tubes over 20 cm (8 inches) in length with one reaching a total height of only 10 cm (4 inches). On two of the five treated columns, the initial tube on the flat edge of the column was abandoned and new tubes were started on the scalloped side of the column. These tubes failed as well. Termites took an average of less than 8 days to complete their tube from the sand to the top of the column on untreated columns. However, they could only reach an average height of 16.5 cm (6.5 inches) in 8 days on treated columns with no further progress beyond that point. The quality of the tubes also varied. The tubes on the untreated columns appeared strong and durable whereas the tubes on the treated columns were weak and crumbly. The tubes on the treated columns were not maintained. In the end, some deterioration was found on all southern yellow pine blocks, whether the column was treated or not. Deterioration was much more severe on the wood supported on the untreated columns. While not intending to be bound by theory, it is believed that some deterioration was observed on the treated columns because with no alternative food source in the experiment, the termites ultimately crossed the column to the food source even without tubes and were able to do this as the test units were enclosed in plastic bags to maintain high humidity. It is believed that this would not happen in nature where alternative food sources are inevitably available and where only tubes will prevent dehydration and death. Referring to FIG. 2, examples of tubing behaviors on columns with and without borate solution coatings are shown. On an exemplary uncoated column 50, termites form a tube 56 on the surface 58 of the uncoated column 50 starting from the base 52 of the uncoated column 50 to the top 54 of the uncoated column 50. In contrast, on a coated column 60, termites begin to form a tube 66 on the surface 68 of the coated column starting from the base 62, but the tube 66 is terminated at a point 70 that is before the top 64 of the coated column. TABLE 2 Beginning Day Day Day Day Day Day Column # Date Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Day 8 Day 9 10 11 12 13 14 15 1 Aug. 26, 2003 0 0.5 0.5 3.75 3.75 3.75 8 8 0 0 0 0 0 0 2 Aug. 26, 2003 0 0.5 0.5 0.5 0.5 0.5 4 4 0 0 0 0 0 0 3 Aug. 26, 2003 0 0 0.5 5 5 5 6.5 6.5 0 0 0 0 0 0 4 Aug. 26, 2003 0 0 2 5 5 5 7 7 0 0 0 0 0 0 5 Aug. 26, 2003 0 0 3.75 6 6 6 8 8 0 0 0 0 0 0 6 Aug. 26, 2003 0 3.5 9 18 18 8 23 top top top top top top top 7 Aug. 22, 2003 7 7.5 16 23 top top top top top top top top top top 8 Aug. 26, 2003 0 0 0 0 0 18.5 23 top top top top top top top 9 Aug. 26, 2003 0 0 0 0 0 0 0 0 0 0 0 0 0 0 10 Aug. 26, 2003 0 0 0 0 0 0 23 top 0 top top top top top Day Day Day Day Day Day Day Day Day Day Day Day Day Day Day Column # 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 1 0 0 0 NM NM 0 0 0 0 0 NM NM 0 0 0 2 0 0 0 NM NM 0 0 0 0 0 NM NM 0 0 0 3 0 0 0 NM NM 0 0 0 0 0 NM NM 0 0 0 4 0 0 0 NM NM 0 0 0 0 0 NM NM 0 0 0 5 0 0 0 NM NM 0 0 0 0 0 NM NM 0 0 0 6 top top top NM NM top top top top top NM NM top top top 7 top top top NM NM top top top top top NM NM top top top 8 top top top NM NM top top top top top NM NM top top top 9 0 15.5 16.5 NM NM 23 top top top top NM NM top top top 10 top top top NM NM top top top top top NM NM top top top EXAMPLE 4 Termite Mortality Termites were found in the water surrounding the setup on a daily basis. These termites were collected and counted providing a daily mortality count. As can be seen in Table 3, there was a significantly larger number of termites that were in the water from the treated columns than the untreated. The treated concrete had an average of 799 termites in the water over the 30 day period or 40% mortality of the original number placed in the test. The mortality of termites used in the untreated concrete test averaged a total of 93 termites or 4.7% mortality. Mortality of the termites on the untreated column due to drowning decreased considerably once the tube reached the top of the column. Mortality of the termites on the treated columns caused by drowning was very high sometimes reaching more than 50% in two weeks on individual columns. A summary of the test breakdown data is provided in Table 4. Data consists of total termite mortality (water mortality plus other) for the concrete column setups and mortality, weight loss, and visual rating for the southern yellow pine block controls in the jar test. As can be seen in this table, there were very high mortality rates for the treated concrete column setup averaging 92.7%, moderate mortality for the untreated columns averaging 35.7%, and low mortality for the pine controls averaging 13.2%. In addition, the higher weight loss for the controls (43.7%), combined with the low ratings (0.8) indicated that the termites were healthy and very active. As shown in Table 4, the very high mortality rate for the treated columns indicates that the treatment also caused death of termites in the sand as well as death by drowning. TABLE 3 Beginning Day Day Day Day Day Day Column # Date Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Day 8 Day 9 10 11 12 13 14 15 1 Aug. 26, 2003 0 68 0 25 0 0 247 61 75 34 0 103 43 39 2 Aug. 26, 2003 0 201 0 55 0 0 23.4 199 108 68 0 163 44 23 3 Aug. 26, 2003 0 106 0 41 0 0 153 63 54 43 0 89 33 25 4 Aug. 26, 2003 0 184 0 30 0 0 121 46 85 39 0 98 28 14 5 Aug. 26, 2003 0 124 0 57 0 0 138 8 21 16 0 22 8 2 6 Aug. 26, 2003 0 14 0 15 0 0 9 0 0 0 0 0 0 0 7 Aug. 26, 2003 0 0 0 0 0 116 0 0 0 0 0 0 0 0 8 Aug. 26, 2003 0 53 0 12 0 0 1 2 0 3 0 1 0 0 9 Aug. 26, 2003 0 2 0 0 1 2 0 1 0 0 10 2 0 0 10 Aug. 26, 2003 0 42 0 2 0 0 3 2 2 2 0 1 0 0 Day Day Day Day Day Day Day Day Day Day Day Day Day Day Day Column # 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 1 39 30 18 NM NM 25 7 2 1 0 NM NM NM NM 3 2 50 27 15 NM NM 36 4 1 0 1 NM NM NM NM 1 3 14 6 21 NM NM 66 5 1 1 6 NM NM NM NM 10 4 35 17 17 NM NM 47 2 3 2 NM NM NM NM 0 5 4 6 2 NM NM 12 2 1 1 3 NM NM NM NM 1 6 0 0 0 NM NM 0 1 1 0 0 NM NM NM NM 0 7 0 0 0 NM NM 1 0 0 0 0 NM NM NM NM 0 8 0 0 0 NM NM 1 0 0 0 0 NM NM NM NM 0 9 1 12 9 NM NM 6 1 1 0 0 NM NM NM NM 0 10 2 0 0 NM NM 0 0 1 0 0 NM NM NM NM 0 TABLE 4 WT/ Total Visual Sample Termite WT Initial Live Live Weight Rating ID gm gm Termites # Workers # Soldiers # Mortality % loss % 0-10 1 0.0046 9.223 2005 419 1 79.05% NA NA 2 0.0046 9.224 2005 0 0 100.00% NA NA 3 0.0046 9.211 2002 137 0 93.16% NA NA 4 0.0046 9.226 2006 68 5 96.36% NA NA 5 0.0046 9.241 2009 95 3 95.12% NA NA Mean 0.0046 9.225 2005.4 143.8 1.8 92.74% St Dev 0 0.011 2.3 161.7 2.2 0.08 6 0.0046 9.255 2012 1251 21 36.78% NA NA 7 0.0043 8.58 1995 1250 NA 37.35% NA NA 8 0.0046 9.243 2009 1011 9 49.24% NA NA 9 0.0046 9.319 2026 1572 9 21.96% NA NA 10 0.0046 9.264 2014 1316 28 33.26% NA NA Mean 0.0045 9.132 2011.3 1280.0 16.8 35.72% St Dev 0.0001 0.310 10.9 200.4 9.4 0.10 C1 0.0046 1.841 400 336 7 14.30% 44.60% 0 C2 0.0046 1.845 401 355 6 9.99% 43.57% 2 C3 0.0046 1.847 402 351 5 11.34% 44.23% 2 C4 0.0046 1.842 400 352 11 9.35% 44.52% 0 C5 0.0046 1.848 402 312 6 20.84% 41.57% 0 Mean 0.0046 1.844 401.0 341.2 7.0 13.16% 43.70% 0.8 St Dev 0 0.003 0.7 17.9 2.3 0.05 1.26% 1.10 While the present invention has been described with reference to several particular implementations, those skilled in the art will recognize that many changes may be made hereto without departing from the spirit and scope of the present invention. | <SOH> BACKGROUND OF THE INVENTION <EOH>Termites are unique among insects in their ability to derive nutritional benefit from cellulose, which is the component of wood and plants that gives structural rigidity to cells. However, as a result of feeding on wood and cellulose containing products, termites can cause significant damage to man-made structures and the cellulose materials contained within. Generally speaking, subterranean termites must stay in close reach of the soil at all times, lest they die from dehydration. Accordingly, wood touching soil is easily accessed and damaged by termites. However, subterranean termites also can build shelter tubing to travel between the soil and wood that is nearby, but not actually touching the soil. The shelter tubing provides a dark, moist environment that protects the termites from sunlight, predators, or dehydration. Termites may also build shelter tubes through the soil to avoid certain highly repellant termiticides. To prevent termite damage, termite barrier insecticides have been applied to soil under and around dwellings for many years as a chemical barrier. Approaches have included the injection or spray application of large volumes of organic pesticides such as organophosphates and pyrethroids into soil prior to the pouring or construction of building foundations. However, this approach causes environmental concerns as the pesticide goes directly into the environment. Moreover, this approach has performance limitations because the pesticide is lost from the vicinity within a 3 to 10 year period, thereafter allowing termite access. Further, rain during construction or some other form of physical activity (digging, walking, pipe laying etc) breaks the barrier and often leads to premature failure of the insecticide treatment. A different approach to termite control has been to apply borates to wood used in construction through spray or pressure applications to poison the termites' food source. Borates have been used in almost all types of wood end use including the treatment of solid wood, plywood and wood composites. The benefits of borates include efficacy against all wood destroying organisms (fungi, boring beetles & termites), low acute mammalian toxicity and low environmental impact. As an example of this approach, a specific glycol borate formulation containing 40 wt. % disodium octaborate tetrahydrate (DOT) and applied diluted in water to 23 wt. % DOT (available commercially as BORA-CARE®), has been demonstrated and approved in the USA as a stand alone alternative to soil poisoning, when sprayed on all structural wood to a height of two feet in new construction. However, treating only structural wood with borates has practical limitations. One limitation of this approach is that a large percentage of new construction uses building materials other than wood. Brick, block, concrete, steel frame, vinyl, stucco, gypsum, expanded foam and polystyrene board are all common construction materials that can be used in the absence of wood, or with a very low volume of wood. While termites generally don't directly damage non-cellulosic materials such as concrete, termites have the ability to build shelter tubing over these non-wood construction materials and then cause damage to books, paper, wall coverings, wood composite fixtures and fitting, hardwood floors, and other wood or cellulose items. Thus, while it is not effective to treat homes and commercial building constructed in this way by treating only structural wood with borates, subterranean termite protection is still warranted. Another approach to the use of borates has been to incorporate them into building products, including cementitious products. However, this approach has not proven effective as it still allows termite tubing over the building material so the terminates can reach other vulnerable items. This approach has a further limitation in that the application of borates to cementitious products may act as a setting retardant and ultimately affect structural integrity of some building products into which it is incorporated. Therefore, a need exists for an environmentally safer way of protecting man-made structures made with non-wood materials, and the contents therein, from termite damage. | <SOH> SUMMARY OF THE INVENTION <EOH>In an embodiment the invention regards a method for preventing termite tunneling and tubing on non-wood and/or non-cellulosic materials by treating non-wood building components comprising the steps of applying a composition to the surfaces of a non-wood building component, wherein the composition comprises a borate component. In another embodiment the invention regards a method for preventing termite damage to man-made structures comprising the steps of mixing borates with a solvent to form a borate solution, obtaining a non-wood building component, coating the non-wood building component with the borate solution, and incorporating the coated non-wood building component into a man-made structure. The invention also regards a non-wood building component comprising a non-wood substrate, and a coating comprising borates, wherein the coating is disposed on the surfaces of the non-wood substrate. The above summary of the present invention is not intended to describe each discussed embodiment of the present invention. This is the purpose of the figures and the detailed description that follows. | 20040116 | 20091006 | 20050908 | 63356.0 | 1 | LEVY, NEIL S | TERMITE TUBING PREVENTATIVE FOR NON-WOOD MATERIALS | SMALL | 0 | ACCEPTED | 2,004 |
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10,759,057 | ACCEPTED | Fixed base assembly of mobile phone | The present invention is to provide a fixed base assembly of mobile phone comprising a base, a cylinder extended upward from the center of the top of the base having one end coupled to a connecting rod, and the other end of the connecting rod able to clamp a mobile phone, wherein the bottom of the base is hollow and connected to the inside of the cylinder, such that the base can be slid, expanded, or contracted up and down along the cylinder. In addition, a clicking member is extended from the cylinder and the base, and the pivotal end of the clicking member symmetrically has a circular protruded head section such that when the clicking end of the clicking member is pressed, the head section of the clicking member presses against the surface of the base to lift the sucking disc of the cylinder, and make the bottom of the sucking disc vacuum and attached onto a fixed object. | 1. A fixed base assembly of mobile phone, comprising: a base, having a hollow cylinder extended upward from the center of the top of said base, a pair of corresponding rectangular through holes being disposed respectively at an extended position of said cylinder and base, such that the bottom of said base being a hollow, and said hollow and said cylinder being interconnected, and the top of said cylinder being coupled to a connecting rod, and one end of said connecting rod being used for clamping a mobile phone; a sucking disc, having an external diameter slightly larger than or equal to the external diameter of the bottom of said base, and a bar-shaped pillar being extended upward from the center of said sucking disc, such that said base being slidably disposed on said sucking disc, and a spring surrounding the periphery of said bar-shaped pillar, such that said base being capable of sliding by expanding and contracting up and down along said pillar, and said pillar comprising a through hole along the direction of the diameter; a clicking member, being coupled to said cylinder and a rectangular through hole at the extended position of said base, and having a pair of corresponding arm sections disposed at a pivotal coupling end of said clicking member, and the other end being a clicking end, and one side of both ends of said two arm sections symmetrically having a circular protruded head section, and a through hole corresponding to said rectangular through hole being disposed on said two arm sections, so that a peg being inserted into said through hole of each of said arm sections, said pair of corresponding rectangular through holes of said cylinder, and said through hole of said sucking disc pillar, so that said sucking disc pillar, said clicking member, and said base being pivotally coupled. 2. The fixed base assembly of mobile phone of claim 1, wherein said clicking member at its clicking end comprises a plurality of protruded bars being disposed equidistant from each other, so that said protruded bars enhance the friction at said clicking end and prevent said clicking end from slipping off. 3. The fixed base assembly of mobile phone of claim 1, wherein said base is a cone symmetrically along the circumference. 4. The fixed base assembly of mobile phone of claim 1, wherein said connecting rod at another end comprises a clamping base for clamping a mobile phone. | BACKGROUND OF THE INVENTION I. Field of the Invention This invention relates to a fixed base assembly of mobile phones. II. Description of the Prior Art In the fast changing and highly efficient environment nowadays, electronic communications products (such as a mobile phone) have become a convenient and efficient communications tool. Since mobile phones are usually placed at a position according to the user's need (such as being hung at the user's waist or neck, or put in a backpack, a bag, or a car, etc.) and such position varies with the actual situation, therefore, it generally requires a fixed base to fix the mobile phone. In the example of putting the mobile phone in a car, the mobile phone is clamped and fixed to one end of a clamping base of the fixed device, and the other end of the fixed device is disposed at an appropriate position in the car, so that the driver can feel relieved and concentrate on driving. However, since there are various designs for the fixed device of mobile phones in the market, therefore a prior-art fixed device which can be attached onto any fixed object in the car (such as a drink holder or a car window, etc) is used for example. Please refer to FIGS. 1 and 2 for the prior-art fixed device. Such fixed device 10 has a base 11 which is a cone symmetrical along the circumference and comprises a hollow cylinder 12 extended upward from the center of the top of the base 11, and a pair of corresponding small and large apertures 121, 122 respectively extended upward from the cylinder 12 and the cone, and the bottom of the cone is hollow, and a stop rod 123 is disposed at the bottom of the large aperture 122 in the cylinder 12. Further, the hollow of the bottom of the cone allows the base 11 to be movably coupled to a sucking disc 13, and the diameter of the sucking disc 13 is slightly larger than or equal to the external diameter of the bottom of the base 11. A bar-shaped pillar is extended upward from the center of the bar-shaped pillar 131, and a channel 132 is disposed on the pillar 131 such that the stop rod 123 in the bottom of the base 11 can be guided into the channel 132 to successfully slide the base 11 onto the sucking disc 13, and the outer periphery of the bar-shaped pillar 131 is surrounded by a spring 133. Further, there is a clicking member 14, which has a head section 141 to be extended into the large aperture 122 of the cylinder 12 and the channel 132 of the pillar 131 of the sucking disc 13, and pivotally coupled to the small aperture 121 by a peg 15. One end of the cylinder 12 of the base 11 is coupled to a connecting rod 16, and the other end of the connecting rod 16 is disposed on a clamping base 161 which is used for clamping the mobile phone. Therefore, if the exposed end 142 of the clicking member 14 is pressed as shown in FIG. 2, the head section 141 presses against the stop rod 123 to compress the spring 133 such that the hollow at the bottom of the base 11 presses on the sucking disc 13 to constitute a vacuum and attaches the bottom of the base 11 onto the sucking disc 13 tightly. The sucking disc 13 will contract inward as the hollow at the bottom of the base 11 is attached by the sucking disc 13 and the sucking disc is further attached securely onto any fixed object in the car. On the other hand, if the exposed end 142 of the clicking member 14 is lifted such that after the force of the head sections 141 pressing against the stop rod 123 is gone, the bottom of the base 11 is lifted and separated from the sucking disc 13 due to the resilience of the spring 133. Therefore, the fixed device 10 can be removed successfully. Although the way of using the base 11 and the sucking disc 13 of the fixed device 10 to work together with the clicking member 14 can attach the sucking disc 13 securely onto a fixed object and fix the mobile phone onto another end of the fixed device 10, the structures of the large aperture 122 on the cylinder 12 of the base 11, the stop rod 123 at the bottom and the sucking disc 13 of the pillar 131, the channel 132 on the pillar 131, and the clicking member 14, etc not only are complicated, but also carry a high manufacturing cost, and make the overall assembling very complicated and laborious. Furthermore, the clicking member 14 will break easily when it has been used for a long time, and has the shortcomings of causing the base 11 unable to operate and to be attached to the sucking disc 13. Therefore, it has a poor stability which definitely affects the utility of the fixed device 10. SUMMARY OF THE INVENTION In view of the shortcomings of the aforementioned conventional fixed device which has a base, a sucking disc, and a clicking member, etc. on one end including the complicated structure, high mold manufacturing cost, overall complicated assembling procedure, easily broken clicking member, and inoperable base and sucking disc, etc, the inventor of the present invention based on years of experience and technologies in the mobile phone earphone industry, and conducted extensive researches and experiments to solve the problems and overcome the shortcomings, and finally invented the “Fixed base of mobile phone” in accordance with this invention. By this invention, the aforementioned shortcomings of the prior can be overcome. The primary object of the invention is to provide a mobile phone fixed base with simple structure, easy-to-make mold, fast assembling, and low cost features. The fixed base comprises a base, a cylinder extended upward from the center of the top of the base, and one end of the cylinder is coupled to a connecting rod, and the other end of the connecting rod can clamp the mobile phone. Further, the bottom of the base is hollow and connected to the inside of the cylinder, such that the base can be slid, expanded, or contracted up and down along the cylinder. In addition, a clicking member is extended from the cylinder and the base, and the pivotal end of the clicking member symmetrically has a circular protruded head section such that when the clicking end of the clicking member is pressed, the head section of the clicking member presses against the surface of the base to lift the sucking disc of the cylinder, and further make the bottom of the sucking disc vacuum and to be attached onto a fixed object. On the other hand, if the clicking end of the clicking member is lifted, the force of the head section of the clicking member pressing against the surface of the base will be eliminated, such that the sucking disc of the cylinder will displace downward due to the resilience of the spring, and thus separating the sucking disc. Therefore, a fixed base can be easily attached to or removed from a fixed object. BRIEF DESCRIPTION OF THE DRAWINGS The accomplishment of the above-mentioned object of the present invention will become apparent from the following description and its accompanying drawings which disclose illustrative an embodiment of the present invention, and are as follows: FIG. 1 is a perspective view of the disassembled parts of the structure of a prior-art fixed device. FIG. 2 is a cross-sectional view of part of a prior-art fixed device. FIG. 3 is a perspective view of the disassembled parts of the structure of a fixed base according to the present invention. FIG. 4 is a cross-sectional view of part of the movements of the fixed base according to the present invention. FIG. 5 is another cross-sectional view of part of the movements of the fixed base according to the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENT Please refer to FIG. 3 for the fixed base assembly of the mobile phone according to the present invention. In the figure, the fixed base comprises a base 30, a sucking disc 40, and a clicking member 50; wherein the base 30 is a cone symmetrical along the circumference; a hollow cylinder 31 is extended upward from the center of the top of the cone; a pair of corresponding rectangular through holes 32 is extended upward respectively from the cylinder 31 and an extended position of the cone; a hollow is disposed at the bottom of the cone; the hollow and the cylinder 31 are interconnected; the top of the cylinder 31 of the base 30 is coupled to a connecting rod 33, and the other end of the connecting rod 33 has a clamping base 34, and the clamping base 34 is used to clamp the mobile phone or digital personal assistance (PDA) (not shown in the figure). Please refer to FIG. 3 again. The hollow at the bottom of the cone can slide the base 30 onto the sucking disc 40, and the external diameter of the sucking disc 40 is slightly greater than (or equal to) the external diameter of the bottom of the base 30. A bar-shaped pillar 41 is extended upward from the center of the sucking disc 40, such that the pillar 41 can be guided into the cylinder 31 from the hollow at the bottom of the base 30, and the base 30 can be slid and disposed successfully onto the sucking disc 40, and a spring 43 is sheathed around the periphery of the bar-shaped pillar 41, such that the base 30 can expand or contract up and down along the pillar 41. Further, a through hole 42 is disposed along the diameter of the pillar 41. Please refer to FIG. 3 again. The clicking member 50 is pivotally disposed on the rectangular through hole 32 at the extended section of the cylinder 31 and the base 30. The pivotal connecting end of the clicking member 50 has a pair of two corresponding arm sections 51; the other end has a clicking end 52; the ends of two arm sections 51 symmetrically disposed on a circular protruded section 53; the two arm sections 51 also has a through hole 54 corresponding to the rectangular through hole 32, so that a peg 60 is inserted into the through hole 54 of the arm section 51, two rectangular through holes 32 responding to the cylinder 31, and the through hole 42 of the cylinder 31 of the sucking disc 40, such that the sucking disc pillar 41, clicking member 50, and base 30 are pivotally coupled. Please refer to FIGS. 4 and 5 for the aforementioned assembly of components. When the fixed base is fixed onto a fixed object 70 (such as a cup holder, or a car window, etc), the clicking end 52 of the clicking member 50 is pressed, and the protruded head section 53 of the clicking member 50 presses against the surface of the base 30 to lift the sucking disc pillar 41 and make the central surface of the bottom of the sucking disc 40 vacuum and to be attached onto a fixed object 70. Please refer to FIGS. 4 and 5 again. On the other hand, when the clicking end 52 of the clicking member 50 is lifted, the force of the protruded head section 53 of the clicking member 50 pressing against the surface of the base 30 will be eliminated, such that the sucking disc pillar 41 will displace downward due to the resilience of the spring 43, so that the sucking disc 40 will be separated, and the fixed base can be easily removed from the fixed object 70. Further, please refer to FIG. 3. A plurality of protruded bars 55 is disposed equidistant apart with each other on the surface of the clicking end 52 of the clicking member 50 for enhancing the frictional force and holding the clicking end 52, so that the clicking end 52 will not slip off from the user's hand easily. In summation of the description above, the most significant feature of this invention resides on the simple design of the structures of the base 30, sucking disc 40, and clicking member, not only having the advantages of the easy-to-make mold, simple assembling, and low manufacturing cost, but also having a very strong structure of clicking member 50, which can prevent the cracking of the clicking member 50 as the traditional clicking member 14 (as shown in FIG. 1) usually breaks after being exerted with a larger clicking force and used for a long time. Thus, this invention can give the best using condition in a long-time use, and the design of this invention can effectively overcome the shortcomings of the traditional device. This invention is regarded as an excellent design. | <SOH> BACKGROUND OF THE INVENTION <EOH>I. Field of the Invention This invention relates to a fixed base assembly of mobile phones. II. Description of the Prior Art In the fast changing and highly efficient environment nowadays, electronic communications products (such as a mobile phone) have become a convenient and efficient communications tool. Since mobile phones are usually placed at a position according to the user's need (such as being hung at the user's waist or neck, or put in a backpack, a bag, or a car, etc.) and such position varies with the actual situation, therefore, it generally requires a fixed base to fix the mobile phone. In the example of putting the mobile phone in a car, the mobile phone is clamped and fixed to one end of a clamping base of the fixed device, and the other end of the fixed device is disposed at an appropriate position in the car, so that the driver can feel relieved and concentrate on driving. However, since there are various designs for the fixed device of mobile phones in the market, therefore a prior-art fixed device which can be attached onto any fixed object in the car (such as a drink holder or a car window, etc) is used for example. Please refer to FIGS. 1 and 2 for the prior-art fixed device. Such fixed device 10 has a base 11 which is a cone symmetrical along the circumference and comprises a hollow cylinder 12 extended upward from the center of the top of the base 11 , and a pair of corresponding small and large apertures 121 , 122 respectively extended upward from the cylinder 12 and the cone, and the bottom of the cone is hollow, and a stop rod 123 is disposed at the bottom of the large aperture 122 in the cylinder 12 . Further, the hollow of the bottom of the cone allows the base 11 to be movably coupled to a sucking disc 13 , and the diameter of the sucking disc 13 is slightly larger than or equal to the external diameter of the bottom of the base 11 . A bar-shaped pillar is extended upward from the center of the bar-shaped pillar 131 , and a channel 132 is disposed on the pillar 131 such that the stop rod 123 in the bottom of the base 11 can be guided into the channel 132 to successfully slide the base 11 onto the sucking disc 13 , and the outer periphery of the bar-shaped pillar 131 is surrounded by a spring 133 . Further, there is a clicking member 14 , which has a head section 141 to be extended into the large aperture 122 of the cylinder 12 and the channel 132 of the pillar 131 of the sucking disc 13 , and pivotally coupled to the small aperture 121 by a peg 15 . One end of the cylinder 12 of the base 11 is coupled to a connecting rod 16 , and the other end of the connecting rod 16 is disposed on a clamping base 161 which is used for clamping the mobile phone. Therefore, if the exposed end 142 of the clicking member 14 is pressed as shown in FIG. 2 , the head section 141 presses against the stop rod 123 to compress the spring 133 such that the hollow at the bottom of the base 11 presses on the sucking disc 13 to constitute a vacuum and attaches the bottom of the base 11 onto the sucking disc 13 tightly. The sucking disc 13 will contract inward as the hollow at the bottom of the base 11 is attached by the sucking disc 13 and the sucking disc is further attached securely onto any fixed object in the car. On the other hand, if the exposed end 142 of the clicking member 14 is lifted such that after the force of the head sections 141 pressing against the stop rod 123 is gone, the bottom of the base 11 is lifted and separated from the sucking disc 13 due to the resilience of the spring 133 . Therefore, the fixed device 10 can be removed successfully. Although the way of using the base 11 and the sucking disc 13 of the fixed device 10 to work together with the clicking member 14 can attach the sucking disc 13 securely onto a fixed object and fix the mobile phone onto another end of the fixed device 10 , the structures of the large aperture 122 on the cylinder 12 of the base 11 , the stop rod 123 at the bottom and the sucking disc 13 of the pillar 131 , the channel 132 on the pillar 131 , and the clicking member 14 , etc not only are complicated, but also carry a high manufacturing cost, and make the overall assembling very complicated and laborious. Furthermore, the clicking member 14 will break easily when it has been used for a long time, and has the shortcomings of causing the base 11 unable to operate and to be attached to the sucking disc 13 . Therefore, it has a poor stability which definitely affects the utility of the fixed device 10 . | <SOH> SUMMARY OF THE INVENTION <EOH>In view of the shortcomings of the aforementioned conventional fixed device which has a base, a sucking disc, and a clicking member, etc. on one end including the complicated structure, high mold manufacturing cost, overall complicated assembling procedure, easily broken clicking member, and inoperable base and sucking disc, etc, the inventor of the present invention based on years of experience and technologies in the mobile phone earphone industry, and conducted extensive researches and experiments to solve the problems and overcome the shortcomings, and finally invented the “Fixed base of mobile phone” in accordance with this invention. By this invention, the aforementioned shortcomings of the prior can be overcome. The primary object of the invention is to provide a mobile phone fixed base with simple structure, easy-to-make mold, fast assembling, and low cost features. The fixed base comprises a base, a cylinder extended upward from the center of the top of the base, and one end of the cylinder is coupled to a connecting rod, and the other end of the connecting rod can clamp the mobile phone. Further, the bottom of the base is hollow and connected to the inside of the cylinder, such that the base can be slid, expanded, or contracted up and down along the cylinder. In addition, a clicking member is extended from the cylinder and the base, and the pivotal end of the clicking member symmetrically has a circular protruded head section such that when the clicking end of the clicking member is pressed, the head section of the clicking member presses against the surface of the base to lift the sucking disc of the cylinder, and further make the bottom of the sucking disc vacuum and to be attached onto a fixed object. On the other hand, if the clicking end of the clicking member is lifted, the force of the head section of the clicking member pressing against the surface of the base will be eliminated, such that the sucking disc of the cylinder will displace downward due to the resilience of the spring, and thus separating the sucking disc. Therefore, a fixed base can be easily attached to or removed from a fixed object. | 20040120 | 20060815 | 20050721 | 99537.0 | 0 | TIEU, BENNY QUOC | FIXED BASE ASSEMBLY OF MOBILE PHONE | SMALL | 0 | ACCEPTED | 2,004 |
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10,759,427 | ACCEPTED | Circular knitting machine | A circular knitting machine provides sinkers to position yarn laps and prevent the sinkers that are moved in an inclined manner in the sinker troughs from hitting yarn feeding plates. The sinker has a nose section to hold the yarn laps at a horizontal high point to prevent the yarn laps from slipping. The sinker has a throat section which has a first end surface and a belly section which has a second end surface that are at different inclined angles to keep the knitting needles and sinkers to move smoothly for knitting operation. The yarn feeding plate has a dodging edge on a distal end formed in a shape according the movement track of the sinker and a slant surface at the front end of the dodging edge to avoid hitting the sinker when the sinker is moved in the sinker trough in an inclined manner. | 1. A circular knitting machine comprising sinkers mounted in an inclined manner and movable in sinker troughs for positioning yarn laps and yarn feeding plates without being hit by the sinkers, wherein: each of the sinkers has a nose section, a belly section connecting to one end of the nose section and a throat section connecting to another end of the nose section, the throat section having one side forming a first end surface, the belly section having an inclined second end surface, the first end surface being horizontal when the sinker is mounted in the sinker trough in the inclined manner for holding the yarn laps at a horizontal high spot through the nose section; and the yarn feeding plate has a dodging edge formed on one distal end in a shape according to a movement track of the sinker, the dodging edge having a slant surface on a front end to avoid hitting the sinker during moving in the sinker trough in an inclined manner. 2. The circular knitting machine of claim 1, wherein the dodging edge is an irregular and continuous curve surface. The circular knitting machine of claim 1, wherein the nose section has a bracing point for positioning the yarn laps. | FIELD OF THE INVENTION The present invention relates to a circular knitting machine and particularly to a circular knitting machine that has sinkers mounted in an inclined manner to position yarn laps and avoid hitting yarn feeding plates when moving in an inclined manner in sinker troughs. BACKGROUND OF THE INVENTION Conventional circular knitting machines generally include sinkers driven by a cam. The cam has a driving path to move the sinkers to and fro to perform knitting operation. The sinker is engaged with a preset driving path as shown in FIG. 1. During knitting operation, the lug 62 of the sinker 61 is engaged with the driving path 64 of the cam 63 so that the sinker 61 is moved according to the driving path 64 to perform knitting operation. The cam 63 is mounted horizontally on the machine deck. The sinker 61 also is mounted horizontally. The sinker 61 is located on a sinker drum 60 which rotates at high speed during knitting operation, and the sinker 61 is driven by the driving path 64 to move reciprocally to and fro rapidly. When the sinker drum 60 rotates at high speed, the sinker 61 is moved outwards at a great centrifugal force. Hence the lug 62 of the sinker 61 does not move smoothly in the driving path 64. To remedy the foregoing problems, Applicant has proposed an improved design that includes a sinker drum with a slant surface so that the cams and sinkers are mounted at an inclined angle against the horizontal surface. The sinkers may be moved in an inclined manner in the sinker troughs of the sinker drum thereby may be driven by the cams more smoothly. Although the slant installation set forth above can reduce the centrifugal force of the sinker that hits the cam and increase the service life of the sinker and the cam, it creates other problems, notably: first, with the sinker directly mounted on the sinker drum in an inclined manner, the surface for holding formed yarn laps on its throat portion also is inclined. As a result, the formed yarn laps tend to slip downwards and stretch the yarn coupled on the needle. Second, with the sinker inclined, the movement of the sinker in the sinker trough also is inclined. As a result, the sinker is prone to hit the yarn feeding plate. The circular knitting machine could become inoperable. The present invention aims to improve these problems. SUMMARY OF THE INVENTION The object of the invention is to provide a circular knitting machine that has yarn feeding plates with a dodging edge and a slant surface formed on each of them to dodge the sinker that is moved in an inclined manner in the sinker drum, and the sinker has a throat section which has one side extended to form an inclined first end surface so that the nose section of the sinker can hold the yarn laps at a higher horizontal spot without slipping even though the sinker is moved in an inclined manner in the sinker drum. The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of conventional cams and sinkers mounted in a horizontal manner. FIG. 2 is a plan view of a sinker of the invention. FIG. 3 is a schematic view of a cam and a sinker of the invention mounted in an inclined manner. FIGS. 4A through 4G are schematic views of the invention in knitting operations. FIG. 5 is a schematic view of the invention showing the inclined installation without generating interference with the yarn feeding plate. FIG. 6 is a front view of the yarn feeding plate of the invention. FIG. 7 is a side view of the yarn feeding plate of the invention. FIG. 8 is a time sequence chart of the sinker moving to and fro according to the invention. FIGS. 9A, 9B and 9C are movement relationships between the sinker and yarn feeding plate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Please referring to FIG. 3, a cam 20 is fastened to a slant surface of a saddle plate (not shown in the drawing) mounted on a machine deck of a circular knitting machine and forms an inclined angle α against the horizontal surface. The cam 20 has a driving path 22 to allow a lug 21 of a sinker 10 to slide therein. The sinker 10 also is mounted in a slant manner to match the cam 20. Referring to FIGS. 2 and 3, the sinker 10 according to the invention includes a belly section 11, a nose section 12 and a throat section 13. The throat section 13 has one end forming a first end surface 131. The belly section 11 has one end forming a second end surface 111. When the sinker 10 is moved because of the lug 21 is driven in the driving path 22 of the cam 20, the first end surface 131 is horizontal while the second end surface 111 is inclined. Refer to FIGS. 6 and 7 for another main element of the invention. A yarn feeding plate 40 has one end forming an elongated mounting section 41 which has two slots 42 and a screw hole 43 for fastening to the machine deck. The yarn feeding plate 40 has other end forming a polygonal yarn feeding section 44 which has a first yarn feeding port 45 and a second yarn feeding port 46 to allow knitting yarns to thread through for feeding. The yarn feeding section 44 has a dodging edge 48 on the bottom surface. The dodging edge 48 is an irregular and continuous curved surface designed according to the moving tracks of the sinker 10 in the driving path 22 of the cam 20 and aims to dodge the sinker 10. The dodging edge 48 has a slant surface 484 at the front edge to avoid hitting the sinker 10 when it is moved in the sinker drum 161 in an inclined manner. Refer to FIGS. 4A and 4B for the invention in use, a pile yarn 17 is threaded through the first yarn feeding port 45, and a bottom yarn 18 is threaded through the second yarn feeding port 46. This paragraph aims to explain the release condition of a yarn lap 17a. First, the sinker 10 is moved in an inclined manner towards the circular center of the circular knitting machine (not shown in the drawings) until reaching a lower dead point (referring to FIG. 4A); meanwhile a needle 15 is lifted fully, and a tie yarn 19 is sunk to the root section of the needle 15; then the sinker 10 is moved rearwards in an inclined manner until reaching an upper dead point (referring to FIG. 4B); the needle 15 is lowered to one half, and the yarn lap 17a escapes the nose section 12 of the sinker 10 and drops onto the second end surface 111 of the belly section 11, and is pulled downwards by the formed and coupled laps 14 in the front to become a release condition; the bottom yarn 18 also drops onto the second end surface 111 of the sinker 10; meanwhile the pile yarn 17 in the first yarn feeding port 45 is pulled downwards by the needle 15. Referring to FIGS. 4C and 4D, the sinker 10 is moved slowly towards the circular center of the knitting machine (not shown in the drawings); the throat section 13 of the sinker 10 (also referring to FIG. 2) picks up the bottom yarn 18; the first end surface 131 of the throat section 131 compresses the formed laps 14 so that they do not float and hinder knitting operation. Referring to FIG. 4E, the sinker 10 is moved slightly forwards, and the needle 15 is moved downwards to the lower dead point; meanwhile the needle 15 pulls the pile yarn 17 downwards and picks up the bottom yarn 18; then the tie yarn 19 is moved upwards from the root section of the needle 15 to close the latch 151 of the needle 15; the tie yarn 19 passes over the periphery of the needle 15 to wrap the pile yarn 17 and the bottom yarn 18 (referring to FIG. 4D); the nose section 12 holds the yarn lap 17a at a high horizontal spot to prevent the yarn lap 17a from slipping down. Thus complete the needle withdrawing and lap forming process. Referring to FIGS. 4F and 4G, the sinker 10 is moved rearwards slightly (in a direction shown by the arrow); the needle 15 is lifted slightly to slightly loosen the yarn lap 17a; meanwhile the yarn lap 17a drops from the top end of the nose section 12 to a bracing point 121; finally the needle 15 is lifted, and the sinker 10 is moved forwards to lift the yarn lap 17a; the tie yarn 19 drops to the root section of the needle 15. Thus complete the knitting operation. The processes set forth may be repeatedly performed to knit a single-face counter-wrapped pile fabric. The operation of the yarn feeding plate 40 and the sinker 10 is elaborated as follow: Referring to FIG. 5, the dodging edge 48 on the distal end of the yarn feeding plate 40 is formed in a shape according to the movement track of the sinker 10 in the driving path 22 of the cam 20. The slant surface 484 on the front side of the dodge edge 48 is formed to avoid hitting the sinker 10 when it is moved in an inclined manner in the sinker trough 161. The dodging edge 48 is formed in an irregular and continuous curved surface as previously mentioned. It includes a first position 481, a second position 482 and a third position 483. The movement relationship of the yarn feeding plate 40 and the sinker 10 is elaborated as follow: First, the sinker 10 is mounted on a sinker drum 16 which is located on an inner annular ring of the circular knitting machine, and is formed in the shape of a conical and shallow tray. The sinker drum 16 has sinker troughs 161 formed on the perimeter in an equally spaced fashion to house the sinkers 10. The sinker drum 16 is rotated at high speed during knitting operation to drive the sinker 10 to turn at high speed. In addition, while the sinker 10 is turning, it also is driven by the driving path 22 of the cam 20 and moved to and fro reciprocally. The movement track of the sinker 10 is determined by the driving path 22 as shown in FIG. 8, which illustrates the track according to time sequence. The irregular and continuous curved surface of the dodging edge 48 of the yarn feeding plate 40 is determined by the movement track of the sinker 10. As the sinker 10 is mounted in an inclined manner and turned continuously and moved reciprocally, it is pone to interfere with the yarn feeding plate 40. The dodging edge 48 of the yarn feeding plate 40 aims to match the movement track of the sinker 10 to prevent such interference. Refer to FIGS. 9A through 9C, and FIGS. 7 and 8 for the sinker 10 in movement conditions. Referring to FIG. 9A, the sinker 10 is located at the front most end (i.e. first point 1 in the time sequence chart shown in FIG. 8). When the sinker 10 is driven and moved along the driving path 22 to the front most position, the yarn feeding plate 40 has a matching concave surface of the first position 481. Referring to FIG. 9B, the sinker 10 is driven by the driving path 22 and moved backwards (in the direction shown by the arrow, at second point 2 in the time sequence chart in FIG. 8) until reaching to the rear most position; the sinker 10 is at the lowest point. The yarn feeding plate 40 is at the second position 482. The irregular and continuous curved surface of the dodging edge 48 has a track same as the one from the first point 1 to the second point 2 in the time sequence chart. Therefore it can avoid hitting the sinker 10 during the to and fro movement and prevent interference. Referring to FIG. 9C, the driving path 22 drives the sinker 10 to move forwards in an inclined manner (also indicated by the arrow direction); the third position 483 of the dodging edge 48 can dodge the sinker 10, and the irregular and continuous curved surface of the dodging edge 48 has a track same as the one moving to the third point 3 in the time sequence chart. Therefore it can avoid hitting the sinker 10 during the to and fro movement and prevent interference. Thus the shape of the dodging edge 48 of the yarn feeding plate 40 is formed according to the movement track of the sinker 10. In addition, the entire irregular and continuous curved surface of the dodging edge 48 also forms an inclined surface 484 at the distal end to match the slant installation of the sinker 10 on the sinker drum 16. Thereby the continuous rotation of the sinker 10 that also is moved in an inclined manner in the sinker trough 161 does not hit the inclined surface 484 at the front end of the dodging edge 48. While the preferred embodiment of the invention has been set forth for the purpose of disclosure, modifications of the disclosed embodiment of the invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are tended to cover all embodiments which do not depart from the spirit and scope of the invention. | <SOH> BACKGROUND OF THE INVENTION <EOH>Conventional circular knitting machines generally include sinkers driven by a cam. The cam has a driving path to move the sinkers to and fro to perform knitting operation. The sinker is engaged with a preset driving path as shown in FIG. 1 . During knitting operation, the lug 62 of the sinker 61 is engaged with the driving path 64 of the cam 63 so that the sinker 61 is moved according to the driving path 64 to perform knitting operation. The cam 63 is mounted horizontally on the machine deck. The sinker 61 also is mounted horizontally. The sinker 61 is located on a sinker drum 60 which rotates at high speed during knitting operation, and the sinker 61 is driven by the driving path 64 to move reciprocally to and fro rapidly. When the sinker drum 60 rotates at high speed, the sinker 61 is moved outwards at a great centrifugal force. Hence the lug 62 of the sinker 61 does not move smoothly in the driving path 64 . To remedy the foregoing problems, Applicant has proposed an improved design that includes a sinker drum with a slant surface so that the cams and sinkers are mounted at an inclined angle against the horizontal surface. The sinkers may be moved in an inclined manner in the sinker troughs of the sinker drum thereby may be driven by the cams more smoothly. Although the slant installation set forth above can reduce the centrifugal force of the sinker that hits the cam and increase the service life of the sinker and the cam, it creates other problems, notably: first, with the sinker directly mounted on the sinker drum in an inclined manner, the surface for holding formed yarn laps on its throat portion also is inclined. As a result, the formed yarn laps tend to slip downwards and stretch the yarn coupled on the needle. Second, with the sinker inclined, the movement of the sinker in the sinker trough also is inclined. As a result, the sinker is prone to hit the yarn feeding plate. The circular knitting machine could become inoperable. The present invention aims to improve these problems. | <SOH> SUMMARY OF THE INVENTION <EOH>The object of the invention is to provide a circular knitting machine that has yarn feeding plates with a dodging edge and a slant surface formed on each of them to dodge the sinker that is moved in an inclined manner in the sinker drum, and the sinker has a throat section which has one side extended to form an inclined first end surface so that the nose section of the sinker can hold the yarn laps at a higher horizontal spot without slipping even though the sinker is moved in an inclined manner in the sinker drum. The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings. | 20040120 | 20061226 | 20050721 | 72572.0 | 0 | WORRELL JR, LARRY D | CIRCULAR KNITTING MACHINE | SMALL | 0 | ACCEPTED | 2,004 |
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10,759,508 | ACCEPTED | Candle having a planar wick and method of and equipment for making same | A candle having a body of a meltable fuel and a planar wick. When lit, the candle provides a unique flame formation, usable in a variety of decorative applications. The wick can be configured to evenly deplete the meltable fuel, while allowing for candles having relatively large and unique body configurations. The body of candle and/or the wick may include scented oil to promote the release of fragrance upon heating. The wick preferably is formed of wood, thereby providing an acoustic contribution to ambiance and improved combustion that generates less soot than conventional cotton wick candles. | 1. A candle comprising: a body of meltable fuel; and a thin flat elongate wood or wood product wick disposed in the body and having an upper end extending above an upper surface of the body. 2. The candle of claim 1 wherein wood grain of the wick is generally straight and vertical. 3. The candle of claim 1 wherein the wick has gum pockets. 4. The candle of claim 1 wherein the wood has a moisture content of ten to twelve percent. 5. The candle of claim 1 wherein the wood family of the wick is Prunus Serotina. 6. The candle of claim 1 wherein the species of wood of the wick is Hardwood. 7. The candle of claim 6 wherein the family of the wood of the wick is Cherry, Poplar, Maple, Birch, Beech, Basswood, Aspen, Yellow Buckeye or Oak. 8. The candle of claim 1 wherein the species of the wood of the wick is Softwood. 9. The candle of claim 8 wherein the family of the wood of the wick is Cedar, Spruce, Cypress, Pine, Pacific Yew, Silverbell or Witch Hazel. 10. The candle of claim 1 wherein the species of the wood of the wick is Tropical Wood. 11. The candle of claim 10 wherein the family of the wood of the wick is Rimo, Pillarwood, Wenge, Rosewood or Bamboo. 12. The candle of claim 1 wherein the wood of the wick has a moisture content of six to fourteen percent. 13. The candle of claim 1 wherein the meltable fuel is petroleum (paraffin), mineral (montan), synthetic wax, clear candle waxes, or “gels” 14. The candle of claim 1 wherein the meltable fuel is a beeswax, carnauba, candelillia or vegetable-based wax. 15. The candle of claim 1 wherein the meltable fuel includes at least one of stearic acids, UV inhibitors, polyethylene, scent oils, or color pigments. 16. The candle of claim 1 wherein the meltable fuel is paraffin. 17. The candle of claim 16 wherein the wick has a thickness of 0.019-0.23 inch. 18. The candle of claim 1 wherein the meltable fuel is a vegetable-based wax. 19. The candle of claim 18 wherein the wick has a thickness of 0.022-0.028 inch. 20. The candle of claim 18 wherein primary components of the vegetable-based wax are palm and soy. 21. The candle of claim 18 wherein primary components of the vegetable-based wax are selected from the group of palm, cotton, olive, linseed, castor, peanut, jojoba and soy. 22. The candle of claim 1 wherein the meltable fuel is a mixture of paraffin and a vegetable-based wax. 23. The candle of claim 1 wherein the body has a diameter of approximately one to six inches and the wick has a width of ⅛ to two inches. 24. The candle of claim 1 wherein the body has a diameter of approximately six to twelve inches and the wick has a width of ⅛-six inches. 25. The candle of claim 24 wherein the number of the wicks in the candle is between one and twelve. 26. The candle of claim 1 wherein the body has a diameter of approximately twelve to twenty-four inches and the wick has a width of ⅛ to twenty inches. 27. The candle of claim 26 wherein the number of the wicks in the candle is between one and twenty. 28. The candle of claim 1 wherein the wood or wood product comprises two sheets of wood with a flat piece of cotton sandwiched therebetween. 29. The candle of claim 1 wherein the wick comprises pressed wood with bits of fiber and adhesive in the pressed wood. 30. The candle of claim 30 wherein the fibers are cellulose materials, cotton, hemp, rayon, linen, paper and/or flax. 31. The candle of claim 29 wherein the adhesive is resin, gum, or natural glue. 32. The candle of claim 1 wherein the body is cylindrical and has a diameter of six inches and the wick is at the axial center of the body. 33. The candle of claim 32 wherein the wick has a width of one and {fraction (1/4)} inches. 34. The candle of claim 1 wherein the wick is sealed with wax. 35. The candle of claim 1 wherein the wick substantially comprises cellulose and lignin. 36. The candle of claim 1 wherein the wick comprises wood particles and gum. 37. The candle of claim 1 wherein the wick is bleached. 38. The candle of claim 1 wherein the wick is dyed. 39. The candle of claim 1 wherein the wick has printed images. 40. The candle of claim 38 wherein the meltable fuel is synthetic wax, clear candle waxes or “gels”. 41. The candle of claim 1 wherein the wick is configured in a selected decorative shape as viewed from above. 42. The candle of claim 1 wherein the wick is straight or curved vertically. 43. The candle of claim 1 wherein the body is cylindrical, elliptic, orbicular, parallelepiped, polyhedron, or organic form and has a diameter of two to twelve inches and the wick is at the axial center of the body. 44. The candle of claim 42 wherein the wick has a width of {fraction (1/4)} inch to six inches. 45. The candle of claim 1 wherein the body is cylindrical, elliptic, orbicular, parallelepiped, polyhedron, or organic form and has a diameter of twelve to twenty-four inches and the wick is at the axial center of the body. 46. The candle of claim 45 wherein the wick has a width of one inch to twelve inches. 47. The candle of claim 1 wherein the wick has a thickness of 0.019-0.028 inch and a width of ⅛ to twelve inches. 48. The wick of claim 46 wherein the primary thickness of the wick is 0.023-0.026 inch. 49. The wick of claim 46 wherein the primary width of the wick is {fraction (3/16)} to three inches. 50. The candle of claim 47 wherein the wick has a height of {fraction (1/2)} inch to four feet. 51. The candle of claim 1 wherein the wick has a height of one inch to six feet. 52. The wick of claim 51 wherein the wick has a primary height of one to nine inches. 53. The candle of claim 1 further comprising a wick holder in a base of the body, the wick holder having an elongate slot in which a lower end of the wick is received. 54. The candle of claim 53 wherein the slot has a width of ¼ to twelve inches and a thickness of 0.018 to 0.03 inch. 55. The candle of claim 1 wherein the wick is rigid such as to be capable of being freestanding. 56. The candle of claim 1 wherein the wick is rigid such as to be capable of being vertically, flat comprising a wick holder. 57. The candle of claim 1 wherein the wood or wood product is a pressed wood particle/powder product or a high density fiberboard material. 58. The candle of claim 1 wherein the wick extends between {fraction (1/16)} to {fraction (1/4)} inch above the upper surface. 59. The candle of claim 1 wherein the fuel is a paraffin-based fuel and the wick extends {fraction (1/8)} inch above the upper surface. 60. The candle of claim 1 wherein the fuel is a vegetable-based fuel and the wick extends {fraction (3/16)} inch above the upper surface. 61. The candle of claim 1 wherein at least one of the body and the wick includes scented oil. 62. The candle of claim 1 wherein the wood or wood product is selected from the group of poplar, cherry, maple, wenge, oak, rosewood and bamboo. 63. The candle of claim 1 wherein the wood or wood product has the wood grain thereof extending longitudinally on the wick. 64. The candle of claim 1 further comprising a container having the body disposed therein. 65. A candle comprising: a body formed of a meltable fuel; and a planar wick disposed in the body and having an upper end extending beyond an upper surface of the body. 66. The candle of claim 65 wherein the meltable fuel is petroleum (paraffin) wax, mineral (montan) wax, synthetic wax, and clear candle waxes or “gels”. 67. The candle of claim 66 wherein the wick has a thickness of 0.019-0.23 inch. 68. The candle of claim 65 wherein the meltable fuel is a beeswax, carnauba, candelillia or vegetable-based wax. 69. The candle of claim 68 wherein the wick has a thickness of 0.022-0.028 inch. 70. The candle of claim 65 wherein the wick is rigid so as to be capable of being freestanding. 71. The candle of claim 65 wherein the wick is made of wood or a wood product. 72. The candle of claim 71 wherein the wick is made of poplar or cherry wood. 73. The candle of claim 71 wherein the wick is made of a pressed wood particle or powder product. 74. The candle of claim 71 wherein the wick is made of a high density fiberboard material. 75. The candle of claim 71 wherein the wick has a width of between ⅛ and 3 inches. 76. The candle of claim 71 wherein the wick has a moisture content of between ten and twelve percent. 77. The candle of claim 71 wherein the wick is made of a cotton and wood construction. 78. The candle of claim 71 wherein the wick has a width of approximately 1¼ inches and the body has a diameter of approximately six inches. 79. The candle of claim 71 wherein the wick extends between {fraction (1/16)} and {fraction (3/16)} inch above the upper surface. 80. The candle of claim 65 wherein the wick extends {fraction (1/8)} inch above the upper surface. 81. The candle of claim 65 wherein the fuel is paraffin. 82. The candle of claim 65 wherein the fuel is a vegetable-based wax. 83. The candle of claim 82 wherein primary components of the vegetable-based wax are palm, cotton, olive, linseed, castor, peanut, jojoba and soy. 84. The candle of claim 65 wherein the planar wick is formed of unwoven, fibrous material. 85. The candle of claim 65 wherein the wick is sized relative to the body to correlate the wick's burn rate with the material of the body to thereby provide an even depletion of the meltable fuel. 86. The candle of claim 65 wherein the wick comprises wood. 87. The candle of claim 65 wherein the meltable fuel is a mixture of paraffin and a vegetable-based wax. 88. The candle of claim 65 wherein the meltable fuel includes at least one of stearic acids, UV inhibitors, polyethylene, scent oils, and color pigments. 89. The candle of claim 65 wherein the body has a diameter of approximately one to six inches and the wick has a width of ⅛ to two inches. 90. The candle of claim 65 wherein the body has a diameter of approximately six to twelve inches and the wick has a width of ⅛-six inches. 91. The candle of claim 90 wherein the number of the wicks in the candle is between one and twelve. 92. The candle of claim 65 wherein the body has a diameter of approximately twelve to twenty-four inches and the wick has a width of ⅛-twenty inches. 93. The candle of claim 92 wherein the number of wicks in the candle is between one and twenty. 94. The candle of claim 65 wherein the planar wick comprises two sheets of wood with a flat piece of cotton sandwiched there between. 95. The candle of claim 65 wherein the planar wick comprises pressed wood with bits of fiber and adhesive in the pressed wood. 96. The candle of wick of claim 95 wherein the fibers are cellulose materials, cotton, hemp, rayon, linen, paper and/or flax. 97. The candle of claim 95 wherein the adhesive is resin, gum, or natural glue. 98. The candle of claim 65 wherein the exterior of the wick is sealed with wax. 99. The candle of claim 65 wherein the wick is largely of cellulose and lignin. 100. The candle of claim 65 wherein the wick comprises wood particles and gum. 101. The candle of claim 65 wherein the wood of the wick is selected from a group consisting of poplar, cherry, maple, wenge, oak, rosewood, and bamboo. 102. The candle of claim 65 wherein the wick is made of wood combined with cotton. 103. The candle of claim 65 wherein the wick is made of wood bonded with natural adhesives or resins. 104. The candle of claim 65 wherein the wick is made from trees or shrubs and consists substantially of cellulose and lignin. 105. The candle of claim 65 wherein the wick is made from leaves or bark and consists substantially of cellulose and lignin. 106. The candle of claim 65 wherein the wick has indicia printed on a flat surface thereof. 107. The candle of claim 65 wherein the wick is bleached or dyed. 108. The candle of claim 65 wherein the wick is curved vertically. 109. The candle of claim 65 wherein the wick comprises a rigid, solid sheet material consisting substantially of cellulose and lignin. 110. The candle of claim 65 further comprising a wick holder which holds the wick. 111. The candle of claim 110 wherein the wick holder includes a base and a slotted support for receiving the wick extending from the base. 112. The candle of claim 65 further comprising a container in which the body is disposed. 113. The candle of claim 65 wherein the wick is configured in a decorative shape as viewed from above. 114. The candle of claim 65 wherein the wick has a width greater than ¼ inch, is rigid so as to be capable of being freestanding and is made at least substantially of wood or cellulose/lignin material. 115. A candle comprising: a body formed of a meltable fuel; and a planar wick disposed in the body and having an upper end extending beyond an upper surface of the body, wherein the wick is formed essentially of wood selected from a group consisting of poplar, cherry, maple, wenge, oak, rosewood, and bamboo. 116. The candle of claim 115 wherein at least one of the body and the wick includes scented oil. 117. The candle of claim 115 further comprising a wick holder having a base and a support for receiving a bottom end of the wick. 118. The candle of claim 115 wherein the wood has a moisture content of 10-12 percent. 119. A method of making a candle, comprising: combining a planar wick and a body of meltable fuel such that the planar wick extends beyond an upper surface of the body. 120. The method of claim 119 wherein the combining includes maintaining the wick in a set position and dispensing the meltable fuel about the wick in a non-solid form and allowing the dispensed meltable fuel to solidify. 121. The method of claim 120 wherein the planar wick comprises wood. 122. The method of claim 121 wherein the wood is selected from a group consisting of poplar, cherry, maple, wenge, oak, rosewood, and bamboo. 123. The method of claim 121 wherein the wood has a moisture content of 10-12 percent. 124. The method of claim 119 further comprising setting the wick in a wick holder. 125. A method of making a candle, comprising: forming a body of meltable fuel having a top surface and a slot engaging the top surface and extending down at least a substantial distance of a height of the body; and inserting a wick into the slot. 126. The method of claim 125 wherein the wick is an elongate planar wick. 127. The method of claim 125 wherein the wick is rigid so as to be capable of being straight freestanding. 128. The method of claim 125 wherein the wick is made of wood or wood product. 129. The method of claim 125 wherein the forming includes positioning an elongate member so that it extends down into a candle mold in a desired position relative thereto; and dispensing the meltable fuel in a flowable condition into the mold around the elongate member; after the dispensing, allowing the fuel to solidify; and thereafter and before the inserting, removing the elongate member from the solidified fuel. 130. The method of claim 129 wherein the positioning includes positioning a positioning device on the mold and the elongate member extending down from the positioning device. 131. The method of claim 130 wherein the positioning includes positioning the positioning device such that it centers the elongate member relative to the mold. 132. The method of claim 131 wherein the positioning the positioning device includes engaging the positioning device on a rim of the mold. 133. The method of claim 130 wherein the forming includes positioning the elongate member in a held position on the positioning device. 134. The method of claim 125 wherein before the inserting, the wick is coated with wax. 135. The method of claim 125 further comprising after the forming, inserting a wick positioning device having a slot in a bottom of the body. 136. The method of claim 135 further comprising inserting a bottom end of the wick in the slot. 137. A candle making assembly, comprising: an elongate member; and a positioning device adapted to engage a candle mold so as to position the elongate member so that it extends down into the candle mold in a wick position. 138. The assembly of claim 137 wherein the positioning device includes a holding device for the elongate member and a pair of support arms extending out from the holding device for engaging a top of the candle mold. 139. The assembly of claim 138 wherein the arms include a plurality of spaced recesses for engaging rims of candle molds of different diameters. 140. The assembly of claim 138 wherein the holding device includes a plurality of resilient fingers for holding elongate members of different widths. 141. A wick sustain device, comprising: a base member; and structure extending up from the base member and defining an upwardly-disposed slot having a height of 0.20 to 0.40 inch and a width of 0.25 to 12 inches. 142. The device of claim 141 wherein the height is approximately ½ inch. 143. The device of claim 141 wherein the width is 0.07 inch. 144. The device of claim 141 wherein the structure includes a pair of opposing plates defining the slot therebetween. 145. The device of claim 144 wherein one of the plates is approximately 0.10 inch taller than the others. 146. The device of claim 144 wherein the plates are arcuately shaped. 147. The device of claim 141 wherein the base member comprises a plate. 148. The device of claim 147 wherein the base member is round, square, rectangular or oval. 149. The device of claim 148 wherein the base member has a diameter of ½ to 12 inches. 150. The device of claim 141 wherein the base member and the structure are formed as a single piece of clear plastic material. 151. A wick holder comprising: a body having a top surface, a bottom surface, two upper walls connected to the top surface and the bottom surface, and a planar bore adapted to receive a planar wick passing through the two upper walls; and a barrier extending horizontally through the upper walls. 152. The wick holder of claim 151 wherein the body is made from a polymer and a ceramic. 153. The wick holder of claim 151 wherein the body is made from polyethersulfone. 154. The wick holder of claim 151 wherein the body has a thickness of {fraction (1/32)} inch. 155. The wick holder of claim 151 wherein the body is non-combustible and intumescent when heated. 156. The wick holder of claim 151 wherein the body is flat, the walls are flat and the barrier is part of the design where the slot/bore stops the wick keeping it from the top of the body. 157. The wick holder of claim 151 wherein the barrier is the raise portion under the wick slot. | CROSS REFERENCE TO RELATED APPLICATIONS This is a continuation-in-part of copending application Ser. No. 10/300,695, filed Nov. 19, 2002, which claims the benefit of U.S. Provisional Application No. 60/331,898, filed Nov. 19, 2001. The entire contents of the '695 application are hereby incorporated by reference. BACKGROUND OF THE INVENTION Historically, candles served a functional purpose, but today they are further used to enhance decoration, aroma and ambiance. References to candles date back to at least 3000 B.C. in Crete and Egypt. Candle making as known today, began in the 13th Century. Candle molding machines were developed in the 15th Century. The braided wick was introduced in 1825. A continuous wicking machine was invented in 1834. Manufactured paraffin was introduced in 1850, providing an alternative to tallow. In 1854 paraffin and stearin were combined to create stronger candles, very similar to those used today. Through the past century, a number of “modern” technical innovations have been introduced to improve candle performance and production. Most of the focus has been towards advancing manufacturing methods (U.S. Pat. Nos. 3,964,858; 4,291,458; 4,830,330; 5,537,989; 5,927,965; 6,228,304), improved wick sustainers (U.S. Pat. Nos. 3,819,342; 4,332,548; 4,818,214; 5,690,484; 5,842,850; 5,961,318; 6,062,847; 6,454,561; 6,508,644), varying waxes formulations (U.S. Pat. Nos. 6,066,329; 6,342,080; 6,562,085; 6,599,334), and improving woven (i.e. braided) wick technology (U.S. Pat. Nos. 3,940,233; 4,790,747; 5,124,200). (The entire contents of all of the patents and other publications mentioned anywhere in this disclosure are hereby incorporated by reference in their entireties.) Traditionally, a candle is made up of a single or multi combustible, porous core or wick surrounded by a fusible, flammable solid wax or wax-like material, such as absolute or blends of petroleum (paraffin) wax, mineral (montan) wax, synthetic wax (polyethylene or Fischer Tropsch), natural waxes (vegetable or animal) and clear candle waxes or “gels” (ETPA). Prior art shows candle wicks referring to cotton or cotton-like materials (i.e. rayon, nylon, hemp) woven, or braided and with or without a “self-supporting” core material such as metal, paper, cotton, polyethylene fiber or a stiffing agent. When a candle is lit, the heat from the flame melts the solid fuel and the resulting liquid then flows up the wick by capillarity. This liquid is subsequently vaporized, the middle zone of the flame is where the vapor is partially decomposed, and the outer layer is marked by combustion of the vapor and the emission of carbon dioxide, water and other vapors into the atmosphere. The wick is the pivotal component for a candle to burn. Although there have been improvements in candle systems and wicks over the past century, there are still complications, limitations and hazards associated with prior wick technologies. In August 1997, ASTM Subcommittee F15.45 was formed to address candle fire safety issues and to set safety standards. The frequency of injuries associated with candles approximately doubled from the mid-1980s to the mid-'90s. They also reported that there had been an increase in the number of candle recalls due to fire safety issues, including excessive flames in gel, terra cotta and metal container candles and various other types of wax candles. Candle sales increased 350 percent while injuries and deaths from candle related fires increased from thirteen to forty-two percent. The candle industry and the CPSC are currently working through ASTM to develop the necessary consensus standards to improve candle fire safety. The primary objective in this cooperative effort is to reduce injuries and deaths associated with candle fires. Although there have not been standardized regulations set forth for candles, testing labs such as FTI/SEA and MTL-ACTS are actively involved in technical evaluations for candles with the National Candle Association (NCA) and/or ASTM. Candle burn testing involves stability, burn time, abnormalities, smoke/flaring, sputter, overflow, re-ignition, flame height, afterglow, external surface temperature (thermocouple), direct flame impingement, pool temperature, carbon deposit and soot emissions. Given that a wick's performance affects all these areas of testing, major improvements and focus must be directed towards advancing wick technology. Prior candle wicks have been woven or braided for well over the last century. Such conventional wicks are woven from multiple fiber or filamentary yarns. The most commonly used yarn is cotton, although other natural fibers such as rayon, nylon or hemp have also been employed. Braided wicks are produced in various sizes, shapes and constructions to achieve the necessary performance (flame height, wax pool size, self-trimming) and process (stability, self-supporting) requirements. The appropriate wick selection for a particular candle application includes type of weave, core, size (diameter or width) and density of wick. Even though wick selection is confined to braided wicks, there are over a thousand different types of braided wicks from which to choose. Consequently, the vast options of wicks may be a disadvantage to manufacturers or consumers, adding additional costs and time spent sourcing a proper wick. Ultimately, braided wicks still have many limitations. Limitations include the wick's aesthetic appearance, and limited design and ambiance alternatives. Although there are thousands of different types of wicks available, they all consist of a white or natural colored, single strand woven material. Additionally, braided wicks only emit a silent, vertical flame. Another limitation with braided wicks is that they do not provide enough capillary flow to optimize the performance of today's candles. When manufacturing a braided wick, increasing the picks per inch will increase the density of the wick (i.e. reduce the yield) and thereby reduce the size of capillaries, thus reducing the potential flame height or burn rate. Conversely, reducing the picks per inch will open the braid and reduce the density of the wick (i.e. increase the yield) and thereby increase the size of capillaries, thus optimizing the flame height or burn rate. However, such an increase in yield and burn rate from conventional braided candle wicks is limited by the fact that creating a more open structure with large capillaries creates a less stable wick which changes in characteristics when subjected to the tensions of the candle manufacturing process. In addition, the smooth surface of a braid reduces the functional surface area. The small capillaries and smooth functional surface area of the braided wick make it more difficult to create the required capillary flow rate in today's natural and gel waxes as well as candles that have high amounts of additives to modify a candle's hardness, color, burn rate and aroma (i.e. stearic acid, UV inhibitors, polyethylene, scent oils and color pigments). Furthermore, today's candles come in different shapes, sizes, and types (i.e. filled, freestanding, taper, tealight and votive), ensuing a need for advanced wick materials and structures. With the succession of oversized and oddly shaped candles (opposed to the traditional cylinder shapes), larger wax pool size and consumption are preferred. Due to wick height standardization by ASTM (i.e. three inches), braided wicks are limited in size and density, thus resulting in limitations in wax pool size, burn rate and consumption. For example, the thicker a cylindrical wick is, the higher its flame height. And flat wicks are restricted in width (i.e. {fraction (1/32)}-{fraction (1/4)} inch) due to the unsupported nature of a braided wick. Even if a “core” or stiffing agent were applied, the wick still remains too flexible. The wider and thicker the braided wick is the more unstable and hazardous it may be. Since the size of the wax pool is related to the burn rate and flame height, braided wicks typically cannot produce a large enough wax pool to consume the majority of a larger candle without compromising the standardized flame height. Characteristically, a braided wick can produce up to a three-inch diameter wax pool while maintaining a three-inch flame height. A traditional six-inch diameter candle requires three braided wicks to maximize consumption. This results in additional manufacturing costs, irregular wax pools and potential hazards. For instance, when one wax pool spills into another, the leaking wax may create unstable flame heights and wick drowning. Prior art shows the need to improve wick technology that allows the wick to burn for a longer period of time and consume more wax than existing wicking material. This was addressed in U.S. Pat. No. 4,790,747, whose wick comprises a single strand of tufted wire coil having a polyethylene and wax coating. One end of the coil is turned upward into a vertical section to form the lighting element and the other end of the wire is wound into a circular base such that it touches the base of the vertical section. Consequently, the wire core technology is manufactured with braided cotton or cotton-like material, generating the same analogous performance complications as disclosed. One category of braided wicks is “self-trimming” or flat wicks (i.e. wicks that curl or bend to the outside of the flame). Although “self-trimming” wicks may reduce afterglow, they may curl to the point where the terminal ends bend into the wax pool or continue to curl into a spiral curl. This undesirable result can cause a self-trimming braided wick to increase in length so as to increase the amount of wick material, or functional surface area, above the melted wax pool, thereby producing a continually increasing (i.e. unstable) flame height and wax pool. Conversely, it is important that a wick does not over-curl or bend to the point were the wick end touches the wax pool, causing the wick to extinguish and drown in molten wax. Consequently to re-ignite the candle, the wick needs to be located and “dug out” since the wax may cool and harden over the wick. The flat wicks are unsupported and very flexible. The alternative category of braided wicks is “self-supporting” wicks. Self-supporting wicks (i.e. “cored wicks”) are typically round in profile and use paper, cotton, metal or polyethylene fiber material in the core of the braid to stiffen the wick. Additionally, a stiffening agent such as wax-insoluble polymer or copolymer that depolymerizes or pyrolyzes may be used to support a flaccid wick. Although many core or stiffing devices are used, braided wicks remain flexible. Due to the flexibility in supported or unsupported woven wicks, several hazards can occur. The majority of household candle fires are the result of a candle wick leaning to one side or another in filled or freestanding candles. Filled candles with flexible wicks, particularly those enclosed in plastic or glass containers, may overheat or contact the side of the container, causing breakage or other damage. Additionally, unsupported wicks may extinguish themselves, falling into the pool of molten wax. Further, freestanding candles with an unsupported wick may incur wax spillage due to a decentralized or irregular shaped wax pool. Certain “self-supporting” wicks may consist of toxic core materials. In April 2003, the Consumer Product Safety Commission (CPSC) banned the manufacture and sale of lead-cored wicks and candles with lead-cored wick because they could present a lead poisoning hazard to young children. This ban became effective in October 2003. The federal ban applies to all domestic and imported candles and will allow the CPSC to seek penalties for violations of the ban. Unfortunately, it is very difficult for consumers to tell if the braided “cored wicks” contain lead. An additional obstacle with prior art wicks involves keeping a braided candle wick trimmed to a ¼ inch length for proper burning, as recommended by ASTM, NCA and most candle manufacturers and testing labs. If a braided wick is not trimmed properly, carbon balls, excessive soot emissions and fire hazards may occur. Candle manufacturers are not required and usually do not distribute a finished candle with a recommended wick size of ¼ inch. Also, due to the nature of cotton-like material and especially “self-supporting” core material, a cutting device is needed to trim the braided wick. If a wick is positioned deep in a narrow candle jar or container, it may become difficult for conventional scissors or cutting device to trim off the excess long wick from the candle. Still, another problem is the difficulty to accurately measure a wick to the exact recommended {fraction (1/4)} inch length. The primary obstruction of prior candle wicks is the emanation of excessive soot developments, resulting in smoke emission and carbon build up. Excessive soot occurs when a candle is burning as a result of the remains of carbon particles that have not been completely decomposed (burned) within the candle flame. Soot will either fully combust and burn off, released into the atmosphere as smoke, or grow into a carbon head or ball, otherwise known as “mushrooming” or “afterglow”. Furthermore, carbon heads can detach from the wick and fall into the pool of liquid fuel, where they accumulate. In addition to creating a polluted looking candle, the liquid fuel may combust, thereby igniting the carbon heads, which become hot enough to vaporize and re-ignite resulting in “flashover.” In freestanding candles, the carbon heads may heat up the wax and burn through the sides and bottom of the candle causing severe damage and fire hazards. In addition, the development of carbon heads (i.e. “afterglow”) causes the emission of unwanted smoke or toxic fumes to linger for several minutes after being extinguished. As a result of an increase in safety requirements and environmental issues, a Smoke Test Method Task Group, formed by ASTM, developed a method to assess the propensity of a candle to smoke. Candle manufacturers and testing labs can use a simple test to measure the smoke from a candle while it is burning that allows them to improve the performance of that candle. The standard test method was recently balloted in January 2003, and the task group will continue to work toward a final standard based on the ballot results. In today's candles a wick sustainer is primarily used to provide lateral support to a wick in a candle to hold the wick in place during pouring of the wax-like material in a container or mold or to laterally support the wick when the hardened wax liquefies, no longer supporting the braided wick. During the manufacturing of filled candles the wick is usually centrally positioned in the bottom of a container with an adhesive to seal the wick sustainer to the bottom. Many wick sustainers are difficult though to position centrally. Additionally, many wick sustainers are made of materials that are not heat resistant or have “self-extinguish” qualities resulting in the overheating of glass causing severe damage, such as by fracturing or cracking. Furthermore, the design of a wick sustain can either amplify or reduce the risk of “flashover.” A variety of wick holders for braided wick technology have been designed over the past decade or so to reduce fire hazards and increase safety. See, e.g., U.S. Pat. Nos. 1,226,850; 1,267,968; 1,309,545; 1,320,109; 1,344,446; 1,505,092; 2,291,067; 2,324,753; 3,462,235; 3,998,922; and 4,381,914. It is known in the art to manufacture “freestanding” candles by molding, and wherein a candle body is molded by casting the wax in a mold having a wick inserted therein. Maintaining the wicks centrally in the mold during such operation is a rather difficult procedure, due to the flexibility of braided wicks. For example, as molten wax cools, it shrinks, causing wick repositioning, which increases the risk of wax spillage as the candle burns. SUMMARY OF THE INVENTION Directed to overcoming the foregoing and other shortcomings and drawbacks of candle wicks and systems heretofore known, the present invention embodies a planar wick and the method and equipment to produce the same. In preferred forms, the present invention includes wood, wood-like or semi-wood wicks that provide improved capillary flow as well as increase the functional surface area. This candle wick provides additional decoration and an acoustic release. In accordance with principles of the present invention, a candle wick is provided which is particularly designed to burn efficiently in a candle system without producing undesirable smoke and carbon heading. In addition, the wicks are capable of creating a more stable and uniform wax pool diameter. The candle wick is designed to change the physical shape of the flame to thereby provide maximum burning efficiency. Candles of the present invention provide a safer, cleaner burning, decorative, multi-sensory alternative to the prior wick technology. The present invention provides a candle having a body of a meltable fuel and a planar wick. The meltable fuel can be vegetable-based, paraffin, beeswax, carnauba, candelillia, polymers, polyolesters or other “fuels” as would be apparent to those skilled in the art from this disclosure. When the wick is lit, the candle provides a unique flame formation, usable in a variety of decorative applications. The wick can be configured to evenly deplete the meltable fuel, while allowing for candles having relatively large and unique body configurations. Optionally, the body of candle and/or the wick may include scented oil to promote the release of fragrance upon heating and the wick may comprise wood, thereby providing an acoustic contribution to ambiance, improved combustion that generates less soot than conventional candles. It is recognized in the analysis of wood that a species or genus or a complete botanical affinity or family name is given. Each species is typically described in terms of its trade, distribution, tree and wood characteristics, including weight, gravity, drying and shrinkage, durability, preservation and toxicity. Wood species are broken down into hardwoods, softwood and tropical woods. There are over 160,000 hardwoods and over 100,000 softwoods available. If anatomical elements are large and irregular, the wood is described as having coarse and uneven texture. If these same features are small and evenly distributed, the texture is fine and uniform. Grain defines the arrangement or alignment of wood tissue; straight, spiral or interlocked. The durability, decay and drying and shrinkage qualities will also effect a wick's function. The key factors in determining an ideal wood species for the use in a candle embodiment include: a fine to medium, uniform texture for a consistent burn; a generally straight and even, vertical grain; resistance to decay; durability (i.e. minimal shifting due to environmental or climate changes); little tendency to split; shock resistance; strong and stable. The key factors in determining a wood species for the use in scent dispensing applications, such as for air fresheners and perfume delivery applications include resistance to decay; minimal shrinkage; strong and stable, permeable; and distinctive scents. In a detailed aspect of a preferred embodiment of the invention, the wick is formed of wood selected from a group consisting of poplar, cherry, maple, wenge, oak, rosewood, and bamboo. The wood can have a moisture content of less than about six percent, or alternatively and preferably between ten and twelve percent. This wick is thereby comprised of a more rigid, viscous material that can produce a larger wax pool and longer burn rate without compromising the flame height. According to another definition of the present invention a candle having a body of meltable fuel and a planar wick is provided. The wick can be made of wood, semi-wood or wood-like material. The wood can be selected from hardwood, softwood or tropical woods preferably with straight, vertical grains; fine to medium and uniform in texture; medium density; moderate to light weight; low shrinkage; excellent strength and stability and resistant to splitting. The semi-wood may be wood combined with cotton or cotton-like material and wood or wood bonded together with natural adhesives or resins, such as particle board. The wood-like material can be any material natural or manmade lamina, replicating rigid, solid sheet-like material, made from materials such as trees, shrubs, leaves and plant tissue and bark. The woodlike material consists largely of cellulose and lignin with vertical, straight grains and a uniform texture. The fibrous rigidity of the wick of the present invention provides centralized wax pools, safe burning candles, and no wick drowning or wick bending. The wick is continuously stable while the candle burns and does not lean while the candle is being manufactured. The wick can be bleached, dyed or printed on such as by printing a message or decorative pattern on the flat surface thereof. The planar wood, semi-wood, wood-like wick may be dipped or coated with a wax to seal the wick from obstructive elements (i.e. fragrance, dyes, acids, oils or other agents) that may affect the capillary flow, therefore allowing the wick to burn more efficiently and consistently. The absorbent wood material of the wick can be adapted to be used as wicks in a variety of applications. For example, porosity of the longitudinal exterior surface of a wick can be highly desirable in scent dispensing applications, such as for air fresheners and perfume delivery applications. The length of the wick exposed to air may be controlled to regulate the rate of scent release. The wick provides an acoustic crackling sound and depending on the combined fuel may emit more or less acoustic sound, as may be desired. Also, the species of wood and amount of viscous sticky substance (i.e. gum or resin) affects the volume of the sound; for example, the Rosaceae family of woods, emit a more acoustic crackling sound due to the integrated gum pockets in the wood. The wick of the present invention advantageously burns cleanly without producing carbon heads, mushrooming or after glow. Due to the lack of carbon buildup, the wick when extinguished discontinues releasing soot within a minute of being extinguished. (In contrast, today's candles continue to release soot for approximately thirty seconds to five minutes.) The wick can be trimmed by breaking the burn wick material off with fingers or a cutting device. Typically, the height of the wick above the wax is ⅛ to {fraction (3/16)} inch. It is easier than braided wicks to trim and determine the correct height. The preferred height of the wick when the candle is manufactured and sold is ⅛ to {fraction (3/16)} inch above the wax. The wick holder raises the wick ⅛ to {fraction (3/16)} inch, thus, extending the wick that distance above the wax for proper burning. The wick can be ⅛ to twenty inches in width depending on the size of the candle container or desired size of the free-standing candle. The height correlates to the size of the candle. The wick can be flat or curved vertically. The wick thickness is determined by the type of wax; vegetable base waxes tend to need thicker wicks compared to petroleum based which is more incendiary. The width is determined by the size of the container verses the thermal flow. For example, a ⅜ inch width wick is typically placed in a three inch diameter petroleum-based pillar, whereas a {fraction (5/16)} inch width wick is placed in a three inch vegetable-based pillar. A four inch round glass container may use a ½ inch width wick with paraffin wax while the same container with vegetable wax may use a {fraction (5/8)} inch width wick. The present invention wick burns cooler thus causing a longer burn rate, lower external temperature and lower container temperature. This is because the emissions of carbon dioxide, water and other vapors are released and burn up causing cleaner combustion. Since the wick extends horizontally, the candle can consume more wax than a single wick than prior art candles, thereby causing longer burn rate and a larger wax pool. The wick can be manufactured by cutting a log vertically from 0.019 to 0.30 inch and then laser or die cutting to an exact size for the desired candle system. Alternatively, the wick can be wood or woodlike particulars or particulated adhered or bonded together with a bonding material, pressed and cut to size. The candle can have a wick sustainer or holder, and the candle can be made of a fuel capable of melting to form a liquid pool and traveling by capillary action to a flame burning on the wick. The wood may be from a family of hardwoods, softwood or tropical woods. The preferred wood qualities are: fine to medium, uniform texture, straight, even vertical grain, high to medium density and strength, light to medium weight and shock and split resistant. Preferred wood species or genus include but are not limited to: Adler, Cedar, Cherry, Cypress, Poplar, Silverbell, Spruce, Rimo, and Pillarwood. Cherry and Poplar are the most abundant and commercially available in the United States. Additional preferred species or genus of wood include: Aspen, Basswood, Beech, Birch, Hard Maple, Pacific Yew, Pine and Witch Hazel, due to their fine to medium, uniform texture; and straight, vertical grain as listed above, although these wood families tend to be heavier, denser and softer. The present invention further relates generally to the field of candle making and in particular to a new and useful sustainer for a planar wick which extinguishes the candle flame and inhibits combustion of residual candle fuel in a container or freestanding for the candle at the end of the candle useful life. The present invention thus advantageously provides for a stable wick construction that improves candle safety and performance by centering the wick and remaining upright. In another detailed aspect of a preferred embodiment of the invention, the candle further includes a wick holder having a base and a support for receiving the planar wick. Optionally, the wick holder is configured to hold a planar wick upright independent of the body. In a method of manufacture, a planar wick supported by a wick holder is positioned within a mold and, thereafter, material of the body is poured into the mold. Once the material sets, the candle can be removed from the mold. The wick holder can comprise a body having a top surface, bottom surface, a pair of upper walls connected to the top and bottom surfaces and a planer bore for receiving the wick passing through the two upper walls. A barrier extends horizontally through the side walls. And the barrier and body are made from noncombustible materials. The upper walls are preferably at least a half inch in height above the bottom of the candle. The raised wick holder is preferably the central position through the body for receiving a wick. The body is preferably {fraction (1/16)} to {fraction (1/8)} inch but it may be cylindrical, pyramid shapes, cube shaped or conical. The diameter is in direct correlation to the size of the diameter of the bottom of the candle or candle holder/container. This keeps the wick always centrally located. The wick holder of the present invention differs from prior art wick holders in the following ways: it is designed to center and hold upright a planar wick, and it is easily inserted into a slit, between two flat walls which hold the wick upright. There is a centering line on the wick sustain to center the wick. Another invention disclosed herein thus relates to a flame retardant wick holder and anti-flash wick support for a candle wick in a candle to additionally minimize the risk of flashover. Using a wick sustain to elevate the exposed portion of the bottom end of a wick from a supporting surface cuts the wick off from the fuel pool once the pool level drops below that portion of the wick, thereby extinguishing the candle and retaining a fuel pool on the supporting surface. This insures that a minimum melt pool remains throughout the lifetime of the candle, and also helps to keep extraneous material away from the flame. In other words, in addition to extinguishing the candle, elevating the wick also separates the primary flame from the extraneous material in the fuel pool as the pool lowers. The wick holder or sustain can be made from polymers or ceramics and preferably polyethersulfone (PES) with a thickness of {fraction (1/32)} inch and which is noncombustible and intumescent when heated, to assist in self-extinguishing and reducing the heat transferred from the wick sustain to the supporting surface. The candle can be manufactured by positioning an elongate member in a desired wick location in a candle mold. The elongate member has the same width and thickness dimensions as the wick to be used. With the elongate member in position the molten wax is poured into the mold around the member. The wax is allowed to solidify and the member then pulled out, leaving (or forming) an elongate slot centered in the wax. The thin planar, substantial rigid wood or wood product wick is then inserted into the straight slot. The end of the wick is inserted into the retaining slot of a wick sustain device press fit into the bottom surface of the candle. To manufacture a candle, a centering device of the present invention for planar wicks provides an improved apparatus and method for preparing and installing wicking in free-standing candle bodies and comprises in its preferred arrangement a station for forming a passageway in a formed candle body to maintain the wick centrally in the mold during such operation. The centering device can be manufactured in metal, polymers or ceramic, preferably polyethersulfane (PES) with a thickness of {fraction (1/32)} inch or applied to and included in these mold compounds polyvinyl chloride, latex systems, silicon rubber systems, polysulfide rubber systems and polyurethane flexible mold compounds. Other objects and advantages of the present invention will become more apparent to those persons having ordinary skill in the art to which the present invention pertains from the foregoing description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the present invention will now be described, by way of example only, with reference to the following drawing figures: FIG. 1 is a perspective view of a candle in accordance with the present invention, the candle having a planar wick; FIG. 2 is a cross-section view taken on line 2-2 of FIG. 1, the candle having a wick holder; FIG. 3 is a plan view of the wick holder of the candle of FIG. 1; FIG. 4 is a cross-sectional view of another preferred embodiment of a candle in accordance with the invention, depicting a body having zones of different melting points; FIG. 5 is a perspective view of another preferred embodiment of a candle in accordance with the invention, depicting a body having an asymmetric configuration; FIG. 6 is an exploded view showing candle-making equipment of the present invention; FIG. 7 is a front view of an alternative holding device of the equipment of FIG. 6; FIG. 8 shows a first process step using the assembled equipment of FIG. 8; FIG. 9 shows a second process step of the present invention; FIG. 10 is an enlarged sectional view showing the wick sustain device of FIG. 9 in position in the candle; FIG. 11 is a perspective view of the wick sustain device of FIGS. 9 and 10 illustrated in isolation; FIG. 12 is a top view thereof; FIG. 13 is a side view thereof; FIG. 14 is a bottom view thereof; and FIG. 15 is a cross-sectional view taken on line 15-15 of FIG. 12. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION With reference to the illustrative drawings, and particularly to FIG. 1, there is shown a candle shown generally at 100 having a body 120 of a meltable fuel and a planar wick 140. When lit, the candle 100 provides a unique flame formation usable in a variety of decorative applications. Optionally, the candle body 120 and/or the wick 140 may include scented oil to promote the release of fragrance upon heating, may be bleached, dyed or printed on for decor, and can be configured to provide an acoustic contribution to ambiance. The material and thickness of the wick 140 are selected to promote the candle's functionality as well as the candle's contributions to ambiance. In a presently preferred embodiment, the wick 140 is made of wood, semi-wood or wood-like material and, when lit, provides a pleasant crackling sound and burns more thoroughly with less carbon heading and sooting than conventional wicks. Processed wood materials such as particleboard and fiberboard may also be used. Overall, woods having relatively straight, condensed grains and without checking make effective wicks. In contrast to traditional wicks, which require periodic trimming, maintenance of wood wicks can be performed with or without any tools. Rather, burned edges of wood wicks can be removed with the user's fingers, before relighting. Empirical testing has shown that woods such as poplar, cherry, maple, wenge, oak, rosewood, and bamboo are effective with both paraffin-based and vegetable oil-based waxes, and are effective when used in conjunction with waxes having melting points between one hundred and ten degrees and one hundred and ninety degrees Fahrenheit. For example, a wick formed of cherry wood having a thickness between {fraction (1/53)} inch and {fraction (1/8)} inch, used in a body of a paraffin or vegetable oil-based wax provides an even burn and a pleasant crackling sound. Hard non-brittle, tight grain woods work best. And cherry is preferred over other species of wood for some applications because its higher oil content gives it more of a desirable crackling sound when burning. Although testing has shown that some woods, such as walnut, ash, birch, pearwood, sapele, pommele, zebrawood, lacewood, mahogany, pine, teak, ebony, and various burls, are not as effective, these woods are still within the scope of the invention. Woods having a moisture level of less than about six percent have been found to work, but moisture contents of between ten and twelve percent are preferred. The wick 140 can have thicknesses of 0.019-0.028 inch, and widths of ⅛ to three inches are the safest. The wick height depends on the candle height and for example can be ½ inch to six feet. Wick dimensions can relate to the type of wax used. While wicks for paraffin candles will be thinner and narrower (approximately 0.019-0.023 inch), wicks for vegetable-based waxes will be thicker (approximately 0.023-0.028 inch). Palm and soy are the main components of vegetable-based waxes. It is also within the scope of the invention to use a paraffin-vegetable-based wax mixture. The wax, fragrance and dye used can all affect the desired wick dimensions. However, as an example for a three-inch diameter candle, a ⅜-{fraction (5/8)} inch wide wick can be used. One way of forming the wood wicks is to have traditional manufacturers of wood veneers for doors, windows and the like, cut the veneers in a certain way. They are then die cut to a specific size, and pressed and dried as needed, since if the wood wick is too moist it may not produce a consistent flame. A moisture content of eight to twenty percent is preferred. Cotton or cotton-like materials can be incorporated into the wood wick construction. One example is to sandwich a piece of cotton between the sheets of wood and seal the sandwiched construction with wax. Another example is to make a wood particle/powder fiberboard with small bits of cotton incorporated therein. With continued reference to FIG. 1, the wick 140 is generally straight, as viewed from above the candle and is relatively thin and pliable. In other embodiments, the wick 140 may be configured in various shapes, bent or straight, as desired. For instance, the wick can be configured, in any decorative shape as viewed from the top, such as an arc, circle, square, triangle, heart, or an alphanumeric shape. Also, the size and shape of the wick are selected to provide even depletion of the meltable material throughout the life of the candle 100, even for unique body configurations (see FIG. 5). For example, the wick of a free-standing candle is sized to create a pool of wax that reaches within ⅛ to {fraction (1/2)} inch from the edge of the body 120. Beneficially, the planar wick 140 allows for a larger candle that depletes evenly. Each candle 100 can have one or more wicks 120 configured in the shape of a sheet. Optionally, the wick 140 can be soaked in scented oil to promote the release of fragrance when burning, or can be bleached, dyed and printed on for decor. Referring now to FIGS. 2 and 3, the candle 100 further includes a wick holder 160 that aids both in the manufacture and use of the candle. The wick holder has a base 180 and a support 200 for receiving the wick. The wick holder can be configured to hold a wood wick upright independent of the body 120. In this embodiment, the base 180 has a width W1 of about 0.05 inch and the support 200 has a width W2 of about 0.09 inch. The support defines a spacing 220 of about 0.02 inch for receiving the wick. With reference now to FIG. 4, the body 120 can be formed to have regions with different melting points. In this embodiment, the body has an inner core 220 of a first melting point and an outer core 240 of a second melting point. The inner core melting point may be in the region of two hundred to two hundred and forty degrees Fahrenheit, and the external region melting point may be between one hundred and twenty and one hundred and sixty degrees Fahrenheit. Although, the preferred melting point of inner core is between one hundred and forty to one hundred and sixty degrees Fahrenheit and the outer core is between one hundred and twenty-five and one hundred and thirty-five degrees Fahrenheit. This may avoid the external appearance of cracks in the candle. In a preferred embodiment, the inner core 220 has a width W of at least 1.5 inches to ensure that the heat of the wick 120 does not promote the fast melting of the external region 140. The external region may have a thickness of at least one inch. The wick 120 should be positioned accurately in the desired location. If it leans to one side on the other as can occur by the tension of the cooling wax, the candle 100 will burn unevenly. To ensure an accurate positioning of the wick 120, unique equipment and manufacturing method have been developed. And the equipment and method can best be understood from FIGS. 6-10, and the discussion below. Referring thereto it is seen that a centering device 300 is provided which centers an elongate member 320, a flat metal, ceramic or plastic rod, in the candle mold 340. More specifically, the holding device, piece 360 is snap fit via a button in the middle of the centering arms (or wings) 380 to form the centering device 300. The elongate member 320 is inserted down into the holding device 360 and held in place by its resilient fingers 300. The fingers 380 can accommodate elongate members (and thus subsequently wicks) of different widths. An alternative holding device construction is shown in FIG. 7 generally at 400. On bottom surfaces of the centering arms are a plurality of protrusions, 420 having the same size and spacing on both sides. The protrusions define grooves 440 for fitting onto the rims 460 of molds 346, as can be seen in FIG. 8. The different spaced grooves 440 allow the centering device 300 to be placed on molds 340 of different diameters and still accurately hold and center the elongate member 320 in the mold. With the centering device 300 in place on the mold 340 and the elongate member (flat rod) 320 centered in the mold as shown in FIG. 8, the desired amount of molten wax 480 is poured into the metal or polyethylene mold 340 around the elongate member 320. The wax 480 is allowed to solidify (which can typically take at least two hours to solidify in a small candle and up to twenty-four hours in a large candle, depending on the type of wax and wax ingredients), and the elongate member 320 pulled out to define a slot 500 in the solidified wax 520, as illustrated in FIG. 9, where the wax is shown removed from the mold. The wick 540 (140) can be dipped or coated with wax before being inserted into the slot 500. This seals the wick 540 so that the dyes and fragrances of the candle wax 540 will not be absorbed into the (porous) wick. A wick sustain device 600 is press fit into the bottom of the candle with the slot 620 thereof aligned with the candle slot 500 and a label (not shown) can be applied to the candle bottom over the bottom of the wick sustain device 600. The (“planar wick”) wick 540 is inserted into the slot 500 in the wax down into the slot 620 of the wick sustain device 600, as illustrated in FIG. 10. The wick 540 is thereby consistently straight and accurately positioned. When the candle burns down to a short height, the wick sustain device 600 holds the wick 540 up. The wick 540 should initially extend up between {fraction (1/16/)}to {fraction (1/4)} inch, and preferably ⅛ or {fraction (3/16)} inch, above the top surface of the candle. If it is too tall, the flame is too high. If it is too short, it is difficult to light. When relighting it, the burnt ash should be removed by hand so that the wood wick 150 extends up about {fraction (3/16)} inch. The wick sustain device 600 is shown in isolation in FIGS. 11-15. It is seen to include a round base member 640 and structure 660 secured thereto and defining the upwardly facing wick-receiving slot 620. The structure is essentially two spaced plates 680, 700, one taller than the other so that the wick is easier to install and is held straight upright. The slot 620 is 0.5 inch long, 1.5 inch wide, and 0.35 inch deep, but not limited to these proportions or dimensions. The base member 640 can have a diameter of two inches. With the wick 540 in place, a finishing step—a topping off—can be conducted. Additional wax can be poured on top of the candle and a heat gun used to smooth it out and put a glaze on it. Standard cotton wick candles have a tall flame height and a small pool size. So for larger candles, more cotton wicks are used for a single candle. This creates inconsistent wax pool and flame height and does not efficiently use the candle. Thus, with the present invention a single longer wick 540 (e.g., 1¼ inches for a six inch candle), with a safe flame height, can be used. Due to a cooler burn the candle lasts longer. It should be appreciated from the foregoing description that the present invention provides candles usable in a variety of decorative applications and having unique flame formations. Optionally, the candle may include scented oil to promote the release of fragrance upon heating and the wick can be made of wood, semi-wood or wood-like material with a straight, vertical grain to provide an acoustic contribution to ambiance when lit. The present invention thus provides a candle having improved combustion, that provides a unique flame formation, that has a wick that is safer, remains rigid throughout its use, improves combustion and that makes an acoustic contribution to ambiance. From the foregoing detailed description, it will be evident that there are a number of changes, adaptations and modifications of the present invention which come within the province of those skilled in the art. The scope of the invention includes any combination of the elements from the different species or embodiments disclosed herein, as well as subassemblies, assemblies, and methods thereof. However, it is intended that all such variations not departing from the spirit of the invention be considered as within the scope thereof. | <SOH> BACKGROUND OF THE INVENTION <EOH>Historically, candles served a functional purpose, but today they are further used to enhance decoration, aroma and ambiance. References to candles date back to at least 3000 B.C. in Crete and Egypt. Candle making as known today, began in the 13th Century. Candle molding machines were developed in the 15th Century. The braided wick was introduced in 1825. A continuous wicking machine was invented in 1834. Manufactured paraffin was introduced in 1850, providing an alternative to tallow. In 1854 paraffin and stearin were combined to create stronger candles, very similar to those used today. Through the past century, a number of “modern” technical innovations have been introduced to improve candle performance and production. Most of the focus has been towards advancing manufacturing methods (U.S. Pat. Nos. 3,964,858; 4,291,458; 4,830,330; 5,537,989; 5,927,965; 6,228,304), improved wick sustainers (U.S. Pat. Nos. 3,819,342; 4,332,548; 4,818,214; 5,690,484; 5,842,850; 5,961,318; 6,062,847; 6,454,561; 6,508,644), varying waxes formulations (U.S. Pat. Nos. 6,066,329; 6,342,080; 6,562,085; 6,599,334), and improving woven (i.e. braided) wick technology (U.S. Pat. Nos. 3,940,233; 4,790,747; 5,124,200). (The entire contents of all of the patents and other publications mentioned anywhere in this disclosure are hereby incorporated by reference in their entireties.) Traditionally, a candle is made up of a single or multi combustible, porous core or wick surrounded by a fusible, flammable solid wax or wax-like material, such as absolute or blends of petroleum (paraffin) wax, mineral (montan) wax, synthetic wax (polyethylene or Fischer Tropsch), natural waxes (vegetable or animal) and clear candle waxes or “gels” (ETPA). Prior art shows candle wicks referring to cotton or cotton-like materials (i.e. rayon, nylon, hemp) woven, or braided and with or without a “self-supporting” core material such as metal, paper, cotton, polyethylene fiber or a stiffing agent. When a candle is lit, the heat from the flame melts the solid fuel and the resulting liquid then flows up the wick by capillarity. This liquid is subsequently vaporized, the middle zone of the flame is where the vapor is partially decomposed, and the outer layer is marked by combustion of the vapor and the emission of carbon dioxide, water and other vapors into the atmosphere. The wick is the pivotal component for a candle to burn. Although there have been improvements in candle systems and wicks over the past century, there are still complications, limitations and hazards associated with prior wick technologies. In August 1997, ASTM Subcommittee F15.45 was formed to address candle fire safety issues and to set safety standards. The frequency of injuries associated with candles approximately doubled from the mid-1980s to the mid-'90s. They also reported that there had been an increase in the number of candle recalls due to fire safety issues, including excessive flames in gel, terra cotta and metal container candles and various other types of wax candles. Candle sales increased 350 percent while injuries and deaths from candle related fires increased from thirteen to forty-two percent. The candle industry and the CPSC are currently working through ASTM to develop the necessary consensus standards to improve candle fire safety. The primary objective in this cooperative effort is to reduce injuries and deaths associated with candle fires. Although there have not been standardized regulations set forth for candles, testing labs such as FTI/SEA and MTL-ACTS are actively involved in technical evaluations for candles with the National Candle Association (NCA) and/or ASTM. Candle burn testing involves stability, burn time, abnormalities, smoke/flaring, sputter, overflow, re-ignition, flame height, afterglow, external surface temperature (thermocouple), direct flame impingement, pool temperature, carbon deposit and soot emissions. Given that a wick's performance affects all these areas of testing, major improvements and focus must be directed towards advancing wick technology. Prior candle wicks have been woven or braided for well over the last century. Such conventional wicks are woven from multiple fiber or filamentary yarns. The most commonly used yarn is cotton, although other natural fibers such as rayon, nylon or hemp have also been employed. Braided wicks are produced in various sizes, shapes and constructions to achieve the necessary performance (flame height, wax pool size, self-trimming) and process (stability, self-supporting) requirements. The appropriate wick selection for a particular candle application includes type of weave, core, size (diameter or width) and density of wick. Even though wick selection is confined to braided wicks, there are over a thousand different types of braided wicks from which to choose. Consequently, the vast options of wicks may be a disadvantage to manufacturers or consumers, adding additional costs and time spent sourcing a proper wick. Ultimately, braided wicks still have many limitations. Limitations include the wick's aesthetic appearance, and limited design and ambiance alternatives. Although there are thousands of different types of wicks available, they all consist of a white or natural colored, single strand woven material. Additionally, braided wicks only emit a silent, vertical flame. Another limitation with braided wicks is that they do not provide enough capillary flow to optimize the performance of today's candles. When manufacturing a braided wick, increasing the picks per inch will increase the density of the wick (i.e. reduce the yield) and thereby reduce the size of capillaries, thus reducing the potential flame height or burn rate. Conversely, reducing the picks per inch will open the braid and reduce the density of the wick (i.e. increase the yield) and thereby increase the size of capillaries, thus optimizing the flame height or burn rate. However, such an increase in yield and burn rate from conventional braided candle wicks is limited by the fact that creating a more open structure with large capillaries creates a less stable wick which changes in characteristics when subjected to the tensions of the candle manufacturing process. In addition, the smooth surface of a braid reduces the functional surface area. The small capillaries and smooth functional surface area of the braided wick make it more difficult to create the required capillary flow rate in today's natural and gel waxes as well as candles that have high amounts of additives to modify a candle's hardness, color, burn rate and aroma (i.e. stearic acid, UV inhibitors, polyethylene, scent oils and color pigments). Furthermore, today's candles come in different shapes, sizes, and types (i.e. filled, freestanding, taper, tealight and votive), ensuing a need for advanced wick materials and structures. With the succession of oversized and oddly shaped candles (opposed to the traditional cylinder shapes), larger wax pool size and consumption are preferred. Due to wick height standardization by ASTM (i.e. three inches), braided wicks are limited in size and density, thus resulting in limitations in wax pool size, burn rate and consumption. For example, the thicker a cylindrical wick is, the higher its flame height. And flat wicks are restricted in width (i.e. {fraction (1/32)}-{fraction (1/4)} inch) due to the unsupported nature of a braided wick. Even if a “core” or stiffing agent were applied, the wick still remains too flexible. The wider and thicker the braided wick is the more unstable and hazardous it may be. Since the size of the wax pool is related to the burn rate and flame height, braided wicks typically cannot produce a large enough wax pool to consume the majority of a larger candle without compromising the standardized flame height. Characteristically, a braided wick can produce up to a three-inch diameter wax pool while maintaining a three-inch flame height. A traditional six-inch diameter candle requires three braided wicks to maximize consumption. This results in additional manufacturing costs, irregular wax pools and potential hazards. For instance, when one wax pool spills into another, the leaking wax may create unstable flame heights and wick drowning. Prior art shows the need to improve wick technology that allows the wick to burn for a longer period of time and consume more wax than existing wicking material. This was addressed in U.S. Pat. No. 4,790,747, whose wick comprises a single strand of tufted wire coil having a polyethylene and wax coating. One end of the coil is turned upward into a vertical section to form the lighting element and the other end of the wire is wound into a circular base such that it touches the base of the vertical section. Consequently, the wire core technology is manufactured with braided cotton or cotton-like material, generating the same analogous performance complications as disclosed. One category of braided wicks is “self-trimming” or flat wicks (i.e. wicks that curl or bend to the outside of the flame). Although “self-trimming” wicks may reduce afterglow, they may curl to the point where the terminal ends bend into the wax pool or continue to curl into a spiral curl. This undesirable result can cause a self-trimming braided wick to increase in length so as to increase the amount of wick material, or functional surface area, above the melted wax pool, thereby producing a continually increasing (i.e. unstable) flame height and wax pool. Conversely, it is important that a wick does not over-curl or bend to the point were the wick end touches the wax pool, causing the wick to extinguish and drown in molten wax. Consequently to re-ignite the candle, the wick needs to be located and “dug out” since the wax may cool and harden over the wick. The flat wicks are unsupported and very flexible. The alternative category of braided wicks is “self-supporting” wicks. Self-supporting wicks (i.e. “cored wicks”) are typically round in profile and use paper, cotton, metal or polyethylene fiber material in the core of the braid to stiffen the wick. Additionally, a stiffening agent such as wax-insoluble polymer or copolymer that depolymerizes or pyrolyzes may be used to support a flaccid wick. Although many core or stiffing devices are used, braided wicks remain flexible. Due to the flexibility in supported or unsupported woven wicks, several hazards can occur. The majority of household candle fires are the result of a candle wick leaning to one side or another in filled or freestanding candles. Filled candles with flexible wicks, particularly those enclosed in plastic or glass containers, may overheat or contact the side of the container, causing breakage or other damage. Additionally, unsupported wicks may extinguish themselves, falling into the pool of molten wax. Further, freestanding candles with an unsupported wick may incur wax spillage due to a decentralized or irregular shaped wax pool. Certain “self-supporting” wicks may consist of toxic core materials. In April 2003, the Consumer Product Safety Commission (CPSC) banned the manufacture and sale of lead-cored wicks and candles with lead-cored wick because they could present a lead poisoning hazard to young children. This ban became effective in October 2003. The federal ban applies to all domestic and imported candles and will allow the CPSC to seek penalties for violations of the ban. Unfortunately, it is very difficult for consumers to tell if the braided “cored wicks” contain lead. An additional obstacle with prior art wicks involves keeping a braided candle wick trimmed to a ¼ inch length for proper burning, as recommended by ASTM, NCA and most candle manufacturers and testing labs. If a braided wick is not trimmed properly, carbon balls, excessive soot emissions and fire hazards may occur. Candle manufacturers are not required and usually do not distribute a finished candle with a recommended wick size of ¼ inch. Also, due to the nature of cotton-like material and especially “self-supporting” core material, a cutting device is needed to trim the braided wick. If a wick is positioned deep in a narrow candle jar or container, it may become difficult for conventional scissors or cutting device to trim off the excess long wick from the candle. Still, another problem is the difficulty to accurately measure a wick to the exact recommended {fraction (1/4)} inch length. The primary obstruction of prior candle wicks is the emanation of excessive soot developments, resulting in smoke emission and carbon build up. Excessive soot occurs when a candle is burning as a result of the remains of carbon particles that have not been completely decomposed (burned) within the candle flame. Soot will either fully combust and burn off, released into the atmosphere as smoke, or grow into a carbon head or ball, otherwise known as “mushrooming” or “afterglow”. Furthermore, carbon heads can detach from the wick and fall into the pool of liquid fuel, where they accumulate. In addition to creating a polluted looking candle, the liquid fuel may combust, thereby igniting the carbon heads, which become hot enough to vaporize and re-ignite resulting in “flashover.” In freestanding candles, the carbon heads may heat up the wax and burn through the sides and bottom of the candle causing severe damage and fire hazards. In addition, the development of carbon heads (i.e. “afterglow”) causes the emission of unwanted smoke or toxic fumes to linger for several minutes after being extinguished. As a result of an increase in safety requirements and environmental issues, a Smoke Test Method Task Group, formed by ASTM, developed a method to assess the propensity of a candle to smoke. Candle manufacturers and testing labs can use a simple test to measure the smoke from a candle while it is burning that allows them to improve the performance of that candle. The standard test method was recently balloted in January 2003, and the task group will continue to work toward a final standard based on the ballot results. In today's candles a wick sustainer is primarily used to provide lateral support to a wick in a candle to hold the wick in place during pouring of the wax-like material in a container or mold or to laterally support the wick when the hardened wax liquefies, no longer supporting the braided wick. During the manufacturing of filled candles the wick is usually centrally positioned in the bottom of a container with an adhesive to seal the wick sustainer to the bottom. Many wick sustainers are difficult though to position centrally. Additionally, many wick sustainers are made of materials that are not heat resistant or have “self-extinguish” qualities resulting in the overheating of glass causing severe damage, such as by fracturing or cracking. Furthermore, the design of a wick sustain can either amplify or reduce the risk of “flashover.” A variety of wick holders for braided wick technology have been designed over the past decade or so to reduce fire hazards and increase safety. See, e.g., U.S. Pat. Nos. 1,226,850; 1,267,968; 1,309,545; 1,320,109; 1,344,446; 1,505,092; 2,291,067; 2,324,753; 3,462,235; 3,998,922; and 4,381,914. It is known in the art to manufacture “freestanding” candles by molding, and wherein a candle body is molded by casting the wax in a mold having a wick inserted therein. Maintaining the wicks centrally in the mold during such operation is a rather difficult procedure, due to the flexibility of braided wicks. For example, as molten wax cools, it shrinks, causing wick repositioning, which increases the risk of wax spillage as the candle burns. | <SOH> SUMMARY OF THE INVENTION <EOH>Directed to overcoming the foregoing and other shortcomings and drawbacks of candle wicks and systems heretofore known, the present invention embodies a planar wick and the method and equipment to produce the same. In preferred forms, the present invention includes wood, wood-like or semi-wood wicks that provide improved capillary flow as well as increase the functional surface area. This candle wick provides additional decoration and an acoustic release. In accordance with principles of the present invention, a candle wick is provided which is particularly designed to burn efficiently in a candle system without producing undesirable smoke and carbon heading. In addition, the wicks are capable of creating a more stable and uniform wax pool diameter. The candle wick is designed to change the physical shape of the flame to thereby provide maximum burning efficiency. Candles of the present invention provide a safer, cleaner burning, decorative, multi-sensory alternative to the prior wick technology. The present invention provides a candle having a body of a meltable fuel and a planar wick. The meltable fuel can be vegetable-based, paraffin, beeswax, carnauba, candelillia, polymers, polyolesters or other “fuels” as would be apparent to those skilled in the art from this disclosure. When the wick is lit, the candle provides a unique flame formation, usable in a variety of decorative applications. The wick can be configured to evenly deplete the meltable fuel, while allowing for candles having relatively large and unique body configurations. Optionally, the body of candle and/or the wick may include scented oil to promote the release of fragrance upon heating and the wick may comprise wood, thereby providing an acoustic contribution to ambiance, improved combustion that generates less soot than conventional candles. It is recognized in the analysis of wood that a species or genus or a complete botanical affinity or family name is given. Each species is typically described in terms of its trade, distribution, tree and wood characteristics, including weight, gravity, drying and shrinkage, durability, preservation and toxicity. Wood species are broken down into hardwoods, softwood and tropical woods. There are over 160,000 hardwoods and over 100,000 softwoods available. If anatomical elements are large and irregular, the wood is described as having coarse and uneven texture. If these same features are small and evenly distributed, the texture is fine and uniform. Grain defines the arrangement or alignment of wood tissue; straight, spiral or interlocked. The durability, decay and drying and shrinkage qualities will also effect a wick's function. The key factors in determining an ideal wood species for the use in a candle embodiment include: a fine to medium, uniform texture for a consistent burn; a generally straight and even, vertical grain; resistance to decay; durability (i.e. minimal shifting due to environmental or climate changes); little tendency to split; shock resistance; strong and stable. The key factors in determining a wood species for the use in scent dispensing applications, such as for air fresheners and perfume delivery applications include resistance to decay; minimal shrinkage; strong and stable, permeable; and distinctive scents. In a detailed aspect of a preferred embodiment of the invention, the wick is formed of wood selected from a group consisting of poplar, cherry, maple, wenge, oak, rosewood, and bamboo. The wood can have a moisture content of less than about six percent, or alternatively and preferably between ten and twelve percent. This wick is thereby comprised of a more rigid, viscous material that can produce a larger wax pool and longer burn rate without compromising the flame height. According to another definition of the present invention a candle having a body of meltable fuel and a planar wick is provided. The wick can be made of wood, semi-wood or wood-like material. The wood can be selected from hardwood, softwood or tropical woods preferably with straight, vertical grains; fine to medium and uniform in texture; medium density; moderate to light weight; low shrinkage; excellent strength and stability and resistant to splitting. The semi-wood may be wood combined with cotton or cotton-like material and wood or wood bonded together with natural adhesives or resins, such as particle board. The wood-like material can be any material natural or manmade lamina, replicating rigid, solid sheet-like material, made from materials such as trees, shrubs, leaves and plant tissue and bark. The woodlike material consists largely of cellulose and lignin with vertical, straight grains and a uniform texture. The fibrous rigidity of the wick of the present invention provides centralized wax pools, safe burning candles, and no wick drowning or wick bending. The wick is continuously stable while the candle burns and does not lean while the candle is being manufactured. The wick can be bleached, dyed or printed on such as by printing a message or decorative pattern on the flat surface thereof. The planar wood, semi-wood, wood-like wick may be dipped or coated with a wax to seal the wick from obstructive elements (i.e. fragrance, dyes, acids, oils or other agents) that may affect the capillary flow, therefore allowing the wick to burn more efficiently and consistently. The absorbent wood material of the wick can be adapted to be used as wicks in a variety of applications. For example, porosity of the longitudinal exterior surface of a wick can be highly desirable in scent dispensing applications, such as for air fresheners and perfume delivery applications. The length of the wick exposed to air may be controlled to regulate the rate of scent release. The wick provides an acoustic crackling sound and depending on the combined fuel may emit more or less acoustic sound, as may be desired. Also, the species of wood and amount of viscous sticky substance (i.e. gum or resin) affects the volume of the sound; for example, the Rosaceae family of woods, emit a more acoustic crackling sound due to the integrated gum pockets in the wood. The wick of the present invention advantageously burns cleanly without producing carbon heads, mushrooming or after glow. Due to the lack of carbon buildup, the wick when extinguished discontinues releasing soot within a minute of being extinguished. (In contrast, today's candles continue to release soot for approximately thirty seconds to five minutes.) The wick can be trimmed by breaking the burn wick material off with fingers or a cutting device. Typically, the height of the wick above the wax is ⅛ to {fraction (3/16)} inch. It is easier than braided wicks to trim and determine the correct height. The preferred height of the wick when the candle is manufactured and sold is ⅛ to {fraction (3/16)} inch above the wax. The wick holder raises the wick ⅛ to {fraction (3/16)} inch, thus, extending the wick that distance above the wax for proper burning. The wick can be ⅛ to twenty inches in width depending on the size of the candle container or desired size of the free-standing candle. The height correlates to the size of the candle. The wick can be flat or curved vertically. The wick thickness is determined by the type of wax; vegetable base waxes tend to need thicker wicks compared to petroleum based which is more incendiary. The width is determined by the size of the container verses the thermal flow. For example, a ⅜ inch width wick is typically placed in a three inch diameter petroleum-based pillar, whereas a {fraction (5/16)} inch width wick is placed in a three inch vegetable-based pillar. A four inch round glass container may use a ½ inch width wick with paraffin wax while the same container with vegetable wax may use a {fraction (5/8)} inch width wick. The present invention wick burns cooler thus causing a longer burn rate, lower external temperature and lower container temperature. This is because the emissions of carbon dioxide, water and other vapors are released and burn up causing cleaner combustion. Since the wick extends horizontally, the candle can consume more wax than a single wick than prior art candles, thereby causing longer burn rate and a larger wax pool. The wick can be manufactured by cutting a log vertically from 0.019 to 0.30 inch and then laser or die cutting to an exact size for the desired candle system. Alternatively, the wick can be wood or woodlike particulars or particulated adhered or bonded together with a bonding material, pressed and cut to size. The candle can have a wick sustainer or holder, and the candle can be made of a fuel capable of melting to form a liquid pool and traveling by capillary action to a flame burning on the wick. The wood may be from a family of hardwoods, softwood or tropical woods. The preferred wood qualities are: fine to medium, uniform texture, straight, even vertical grain, high to medium density and strength, light to medium weight and shock and split resistant. Preferred wood species or genus include but are not limited to: Adler, Cedar, Cherry, Cypress, Poplar, Silverbell, Spruce, Rimo, and Pillarwood. Cherry and Poplar are the most abundant and commercially available in the United States. Additional preferred species or genus of wood include: Aspen, Basswood, Beech, Birch, Hard Maple, Pacific Yew, Pine and Witch Hazel, due to their fine to medium, uniform texture; and straight, vertical grain as listed above, although these wood families tend to be heavier, denser and softer. The present invention further relates generally to the field of candle making and in particular to a new and useful sustainer for a planar wick which extinguishes the candle flame and inhibits combustion of residual candle fuel in a container or freestanding for the candle at the end of the candle useful life. The present invention thus advantageously provides for a stable wick construction that improves candle safety and performance by centering the wick and remaining upright. In another detailed aspect of a preferred embodiment of the invention, the candle further includes a wick holder having a base and a support for receiving the planar wick. Optionally, the wick holder is configured to hold a planar wick upright independent of the body. In a method of manufacture, a planar wick supported by a wick holder is positioned within a mold and, thereafter, material of the body is poured into the mold. Once the material sets, the candle can be removed from the mold. The wick holder can comprise a body having a top surface, bottom surface, a pair of upper walls connected to the top and bottom surfaces and a planer bore for receiving the wick passing through the two upper walls. A barrier extends horizontally through the side walls. And the barrier and body are made from noncombustible materials. The upper walls are preferably at least a half inch in height above the bottom of the candle. The raised wick holder is preferably the central position through the body for receiving a wick. The body is preferably {fraction (1/16)} to {fraction (1/8)} inch but it may be cylindrical, pyramid shapes, cube shaped or conical. The diameter is in direct correlation to the size of the diameter of the bottom of the candle or candle holder/container. This keeps the wick always centrally located. The wick holder of the present invention differs from prior art wick holders in the following ways: it is designed to center and hold upright a planar wick, and it is easily inserted into a slit, between two flat walls which hold the wick upright. There is a centering line on the wick sustain to center the wick. Another invention disclosed herein thus relates to a flame retardant wick holder and anti-flash wick support for a candle wick in a candle to additionally minimize the risk of flashover. Using a wick sustain to elevate the exposed portion of the bottom end of a wick from a supporting surface cuts the wick off from the fuel pool once the pool level drops below that portion of the wick, thereby extinguishing the candle and retaining a fuel pool on the supporting surface. This insures that a minimum melt pool remains throughout the lifetime of the candle, and also helps to keep extraneous material away from the flame. In other words, in addition to extinguishing the candle, elevating the wick also separates the primary flame from the extraneous material in the fuel pool as the pool lowers. The wick holder or sustain can be made from polymers or ceramics and preferably polyethersulfone (PES) with a thickness of {fraction (1/32)} inch and which is noncombustible and intumescent when heated, to assist in self-extinguishing and reducing the heat transferred from the wick sustain to the supporting surface. The candle can be manufactured by positioning an elongate member in a desired wick location in a candle mold. The elongate member has the same width and thickness dimensions as the wick to be used. With the elongate member in position the molten wax is poured into the mold around the member. The wax is allowed to solidify and the member then pulled out, leaving (or forming) an elongate slot centered in the wax. The thin planar, substantial rigid wood or wood product wick is then inserted into the straight slot. The end of the wick is inserted into the retaining slot of a wick sustain device press fit into the bottom surface of the candle. To manufacture a candle, a centering device of the present invention for planar wicks provides an improved apparatus and method for preparing and installing wicking in free-standing candle bodies and comprises in its preferred arrangement a station for forming a passageway in a formed candle body to maintain the wick centrally in the mold during such operation. The centering device can be manufactured in metal, polymers or ceramic, preferably polyethersulfane (PES) with a thickness of {fraction (1/32)} inch or applied to and included in these mold compounds polyvinyl chloride, latex systems, silicon rubber systems, polysulfide rubber systems and polyurethane flexible mold compounds. Other objects and advantages of the present invention will become more apparent to those persons having ordinary skill in the art to which the present invention pertains from the foregoing description taken in conjunction with the accompanying drawings. | 20040115 | 20130108 | 20050217 | 72890.0 | 1 | PRICE, CARL D | CANDLE HAVING A PLANAR WICK AND METHOD OF AND EQUIPMENT FOR MAKING SAME | UNDISCOUNTED | 1 | CONT-ACCEPTED | 2,004 |
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10,759,811 | ACCEPTED | Surgical access system and related methods | A surgical access system including a tissue distraction assembly and a tissue retraction assembly, both of which may be equipped with one or more electrodes for use in detecting the existence of (and optionally the distance and/or direction to) neural structures before, during, and after the establishment of an operative corridor to a surgical target site. | 1. A system for accessing a surgical target site within a spine, comprising: a distraction assembly adapted to create a distraction corridor to said surgical target site; a primary retractor assembly having a handle assembly and a first retractor blade, a second retractor blade, and a third retractor blade removably coupled to said handle assembly, said handle assembly adapted to move said first, second and third retractor blades between a closed position and an open position, said closed position being characterized by said first, second and third retractor blades being positioned generally adjacent to one another, said open position being characterized by said first, second and third retractor blades being positioned generally away from one another, wherein said first, second and third retractor blades are adapted to be introduced simultaneously over said distraction assembly while in said closed position to said surgical target site and thereafter moved to said open position to create and maintain an operative corridor to said surgical target site; and a supplemental retractor assembly having an arm with a fourth retractor blade removably coupled to said arm, said arm adapted to be selectively coupled to said handle assembly of said primary retractor assembly, and said fourth retractor blade adapted to be introduced into said surgical target site and moved to expand said operative corridor. 2. The system of claim 1, wherein said distraction assembly includes a K-wire adapted to be introduced to said surgical target site and an initial dilator capable of being slideably passed over said K-wire to perform initial distraction. 3. The system of claim 1, wherein said distraction assembly includes a plurality of sequential dilators. 4. The system of claim 2, wherein said initial dilator is a split dilator capable of being split after introduction to perform said initial distraction. 5. The system of claim 1, further comprising at least one shim member adapted to be coupled to at least one of said retractor blades, said shim member including a contiguous extension dimensioned to extend past said retractor blade into the surgical target site. 6. The system of claim 5, wherein at least one of said distraction assembly, one of said retractor blades, and said at least one shim member includes at least one stimulation electrode. 7. The system of claim 6, further comprising a control unit capable of electrically stimulating said at least one stimulation electrode, sensing a response of a nerve depolarized by said stimulation, determining a direction from at least one of said initial distraction system, one of said retractor blades, and said at least one shim member to the nerve based upon the sensed response, and communicating said direction to a user. 8. The system of claim 7, further comprising an electrode configured to sense a neuromuscular response of a muscle coupled to said depolarized nerve, the electrode being operable to send the response to the control unit. 9. The system of claim 2, wherein said K-wire has a first stimulation electrode at a distal tip of the K-wire. 10. (canceled) 11. The system of claim 1, wherein said system for establishing an operative corridor to a surgical target site within a spine is configured to establish said operative corridor via at least one of a posterior, anterior, postero-lateral, and a lateral, trans-psoas approach. 12. The system of claim 7, further comprising a handle coupled to at least one of said initial distraction assembly, one of said retractor blades, and said at least one shim member, the handle having at least one button for initiating the electrical stimulation from said control unit to said at least one stimulation electrode. 13. The system of claim 7, wherein the control unit comprises a display operable to display an electromyographic (EMG) response of the muscle. 14. The system of claim 7, wherein the control unit comprises a touch-screen display operable to receive commands from a user. 15. The system of claim 7, wherein the stimulation electrodes are positioned near a distal end of at least one of the initial distraction system, one of said retractor blades, and said at least one shim member. 16. A method of accessing a surgical target site within a spine, comprising the steps of: (a) creating a distraction corridor to the surgical target site; (b) removably coupling a first retractor blade, a second retractor blade, and a third retractor blade to a handle assembly capable of moving said first, second and third retractor blades from a closed position to an open position, said closed position being characterized by said first, second and third retractor blades being positioned generally adjacent to one another and said open position characterized by said first, second and third retractor blades being positioned generally away from one another; (c) simultaneously introducing said first, second, and third retractor blades into said distraction corridor while in said closed position; (d) actuating said handle assembly to open first, second and third retractor blades to create an operative corridor to said surgical target site; (e) coupling a fourth retractor blade to said handle assembly after said first, second, and third retractor blades have been moved to said open position; and (f) moving said fourth retractor blade to expand said operative corridor. 17. The method of claim 16, wherein said step of creating a distraction corridor is accomplished by introducing a K-wire to said surgical target site and thereafter slideably advancing at least one dilator over said K-wire. 18. The method of claim 17, further comprising a step of performing a secondary distraction from said distraction corridor. 19. The method of claim 18, wherein said step of performing secondary distraction is accomplished by using a sequential dilation system. 20. The method of claim 16, further comprising the steps of performing neuromonitoring during at least one of steps (a), (c), (d), and (f), and communicating the result of said neuromonitoring to a user. | CROSS-REFERENCES TO RELATED APPLICATIONS The present application is an application for US Letters Patent of and claims the benefit of priority from commonly owned and co-pending U.S. Provisional Patent Application Ser. No. 60/440,905 (filed Jan. 16, 2003), the entire contents of which is hereby expressly incorporated by reference into this disclosure as if set forth fully herein. The present application also incorporates by reference the following co-pending and co-assigned patent applications in their entireties (collectively, the “NeuroVision Applications”): PCT App. Ser. No. PCT/US02/22247, entitled “System and Methods for Determining Nerve Proximity, Direction, and Pathology During Surgery,” filed on Jul. 11, 2002; PCT App. Ser. No. PCT/US02/30617, entitled “System and Methods for Performing Surgical Procedures and Assessments,” filed on Sep. 25, 2002; PCT App. Ser. No. PCT/US02/35047, entitled “System and Methods for Performing Percutaneous Pedicle Integrity Assessments,” filed on Oct. 30, 2002; PCT App. Ser. No. PCT/US03/02056, entitled “System and Methods for Determining Nerve Direction to a Surgical Instrument,” filed Jan. 15, 2003 (collectively “NeuroVision PCT Applications”). BACKGROUND OF THE INVENTION I. Field of the Invention The present invention relates generally to systems and methods for performing surgical procedures and, more particularly, for accessing a surgical target site in order to perform surgical procedures. II. Discussion of the Prior Art A noteworthy trend in the medical community is the move away from performing surgery via traditional “open” techniques in favor of minimally invasive or minimal access techniques. Open surgical techniques are generally undesirable in that they typically require large incisions and high amounts of tissue displacement to gain access to the surgical target site, which produces concomitantly high amounts of pain, lengthened hospitalization (increasing health care costs), and high morbidity in the patient population. Less-invasive surgical techniques (including so-called “minimal access” and “minimally invasive” techniques) are gaining favor due to the fact that they involve accessing the surgical target site via incisions of substantially smaller size with greatly reduced tissue displacement requirements. This, in turn, reduces the pain, morbidity and cost associated with such procedures. The access systems developed to date, however, fail in various respects to meet all the needs of the surgeon population. One drawback associated with prior art surgical access systems relates to the ease with which the operative corridor can be created, as well as maintained over time, depending upon the particular surgical target site. For example, when accessing surgical target sites located beneath or behind musculature-or other relatively strong tissue (such as, by way of example only, the psoas muscle adjacent to the spine), it has been found that advancing an operative corridor-establishing instrument directly through such tissues can be challenging and/or lead to unwanted or undesirable effects (such as stressing or tearing the tissues). While certain efforts have been undertaken to reduce the trauma to tissue while creating an operative corridor, such as (by way of example only) the sequential dilation system of U.S. Pat. No. 5,792,044 to Foley et al., these attempts are nonetheless limited in their applicability based on the relatively narrow operative corridor. More specifically, based on the generally cylindrical nature of the so-called “working cannula,” the degree to which instruments can be manipulated and/or angled within the cannula can be generally limited or restrictive, particularly if the surgical target site is a relatively deep within the patient. Efforts have been undertaken to overcome this drawback, such as shown in U.S. Pat. No. 6,524,320 to DiPoto, wherein an expandable portion is provided at the distal end of a cannula for creating a region of increased cross-sectional area adjacent to the surgical target site. While this system may provide for improved instrument manipulation relative to sequential dilation access systems (at least at deep sites within the patient), it is nonetheless flawed in that the deployment of the expandable portion may inadvertently compress or impinge upon sensitive tissues adjacent to the surgical target site. For example, in anatomical regions having neural and/or vasculature structures, such a blind expansion may cause the expandable portion to impinge upon these sensitive tissues and cause neural and/or vasculature compromise, damage and/or pain for the patient. This highlights yet another drawback with the prior art surgical access systems, namely, the challenges in establishing an operative corridor through or near tissue having major neural structures which, if contacted or impinged, may result in neural impairment for the patient. Due to the threat of contacting such neural structures, efforts thus far have largely restricted to establishing operative corridors through tissue having little or substantially reduced neural structures, which effectively limits the number of ways a given surgical target site can be accessed. This can be seen, by way of example only, in the spinal arts, where the exiting nerve roots and neural plexus structures in the psoas muscle have rendered a lateral or far lateral access path (so-called trans-psoas approach) to the lumbar spine virtually impossible. Instead, spine surgeons are largely restricted to accessing the spine from the posterior (to perform, among other procedures, posterior lumbar interbody fusion (PLWF)) or from the anterior (to perform, among other procedures, anterior lumbar interbody fusion (ALIF)). Posterior-access procedures involve traversing a shorter distance within the patient to establish the operative corridor, albeit at the price of oftentimes having to reduce or cut away part of the posterior bony structures (i.e. lamina, facets, spinous process) in order to reach the target site (which typically comprises the disc space). Anterior-access procedures are relatively simple for surgeons in that they do not involve reducing or cutting away bony structures to reach the surgical target site. However, they are nonetheless disadvantageous in that they require traversing through a much greater distance within the patient to establish the operative corridor, oftentimes requiring an additional surgeon to assist with moving the various internal organs out of the way to create the operative corridor. The present invention is directed at eliminating, or at least minimizing the effects of, the above-identified drawbacks in the prior art. SUMMARY OF THE INVENTION The present invention accomplishes this goal by providing a novel access system and related methods which, according to one embodiment, involves detecting the existence of (and optionally the distance and/or direction to) neural structures before, during, and after the establishment of an operative corridor through (or near) any of a variety of tissues having such neural structures which, if contacted or impinged, may otherwise result in neural impairment for the patient. It is expressly noted that, although described herein largely in terms of use in spinal surgery, the access system of the present invention is suitable for use in any number of additional surgical procedures wherein tissue having significant neural structures must be passed through (or near) in order to establish an operative corridor. The present invention accomplishes this goal by providing a novel access system and related methods which involve: (1) distracting the tissue between the patient's skin and the surgical target site to create an area of distraction (otherwise referred to herein as a “distraction corridor”); (2) retracting the distraction corridor to establish and maintain an operative corridor; and/or (3) detecting the existence of (and optionally the distance and/or direction to) neural structures before, during and after the establishment of the operative corridor through (or near) any of a variety of tissues having such neural structures which, if contacted or impinged, may otherwise result in neural impairment for the patient. As used herein, “distraction” or “distracting” is defined as the act of creating a corridor (extending to a location at or near the surgical target site) having a certain cross-sectional area and shape (“distraction corridor”), and “retraction” or “retracting” is defined as the act of creating an operative corridor by increasing or maintaining the cross-sectional area of the distraction corridor (and/or modifying its shape) with at least one retractor blade such that surgical instruments can be passed through operative corridor to the surgical target site. According to one broad aspect of the present invention, the access system comprises a tissue distraction assembly and a tissue retraction assembly, both of which may be equipped with one or more electrodes for use in detecting the existence of (and optionally the distance and/or direction to) neural structures during the steps tissue distraction and/or retraction. To accomplish this, one or more stimulation electrodes are provided on the various components of the distraction assemblies and/or retraction assemblies, a stimulation source (e.g. voltage or current) is coupled to the stimulation electrodes, a stimulation signal is emitted from the stimulation electrodes as the various components are advanced towards the surgical target site, and the patient is monitored to determine if the stimulation signal causes muscles associated with nerves or neural structures within the tissue to innervate. If the nerves innervate, this indicates that neural structures may be in close proximity to the distraction and/or retraction assemblies. This monitoring may be accomplished via any number of suitable fashions, including but not limited to observing visual twitches in muscle groups associated with the neural structures likely to found in the tissue, as well as any number of monitoring systems. In either situation (traditional EMG or surgeon-driven EMG monitoring), the access system of the present invention may advantageously be used to traverse tissue that would ordinarily be deemed unsafe or undesirable, thereby broadening the number of manners in which a given surgical target site may be accessed. The tissue distraction assembly is capable of, as an initial step, distracting a region of tissue between the skin of the patient and the surgical target site. The tissue retraction assembly is capable of, as a secondary step, being introduced into this distracted region to thereby define and establish the operative corridor. Once established, any of a variety of surgical instruments, devices, or implants may be passed through and/or manipulated within the operative corridor depending upon the given surgical procedure. The electrode(s) are capable of, during both tissue distraction and retraction, detecting the existence of (and optionally the distance and/or direction to) neural structures such that the operative corridor may be established through (or near) any of a variety of tissues having such neural structures which, if contacted or impinged, may otherwise result in neural impairment for the patient. In this fashion, the access system of the present invention may be used to traverse tissue that would ordinarily be deemed unsafe or undesirable, thereby broadening the number of manners in which a given surgical target site may be accessed. The tissue distraction assembly may include any number of components capable of performing the necessary distraction. By way of example only, the tissue distraction assembly may include a K-wire, an initial dilator (of split construction or traditional non-slit construction), and one or more dilators of traditional (that is, non-split) construction for performing the necessary tissue distraction to receive the remainder of the tissue retractor assembly thereafter. One or more electrodes may be provided on one or more of the K-wire and dilator(s) to detect the presence of (and optionally the distance and/or direction to) neural structures during tissue distraction. The tissue retraction assembly may include any number of components capable of performing the necessary retraction. By way of example only, the tissue retraction assembly may include one or more retractor blades extending proximally from the surgical target site for connection with a pivot linkage assembly. The pivot linkage includes first and second pivot arms capable of maintaining the retractor blades in a first, closed position to facilitate the introduction of the retractor blades over the distraction assembly. Thereafter, the pivot linkage may be manipulated to open the retractor assembly; that is, allowing the retractor blades to separate from one another (preferably simultaneously) to create an operative corridor to the surgical target site. In a preferred embodiment, this is accomplished by maintaining a posterior retractor blade in a fixed position relative to the surgical target site (so as to avoid having it impinge upon any exiting nerve roots near the posterior elements of the spine) while the additional retractor blades (i.e. cephalad, caudal and/or anterior retractor blades) are moved or otherwise translated away from the posterior retractor blade (and each other) so as to create the operative corridor in a fashion that doesn't infringe upon the region of the exiting nerve roots. This is accomplished, in part, through the use of a secondary pivot linkage coupled to the pivot linkage assembly, which allows the posterior retractor blade to remain in a constant position while the other retractor blades are moved. In one embodiment, the anterior retractor blade may be positioned after the posterior, cephalad, and caudal retractor blades are positioned into the fully retracted position. This may be accomplished by coupling the anterior retractor blade to the pivot linkage via an arm assembly. The retractor blades may be optionally dimensioned to receive and direct a rigid shim element to augment the structural stability of the retractor blades and thereby ensure the operative corridor, once established, will not decrease or become more restricted, such as may result if distal ends of the retractor blades were permitted to “slide” or otherwise move in response to the force exerted by the displaced tissue. In a preferred embodiment, only the posterior and anterior retractor blades are equipped with such rigid shim elements, which are advanced into the disc space after the posterior and anterior retractor blades are positioned (posterior first, followed by anterior after the cephalad, caudal and anterior blades are moved into the fully retracted position). The rigid shim elements are preferably oriented within the disc space such that they distract the adjacent vertebral bodies, which serves to restore disc height. They are also preferably advanced a sufficient distance within the disc space (preferably past the midline), which serves the dual purpose of preventing post-operative scoliosis and forming a protective barrier (preventing the migration of tissue (such as nerve roots) into the operative field and the inadvertent advancement of instruments outside the operative field). The retractor blades may optionally be equipped with a mechanism for transporting or emitting light at or near the surgical target site to aid the surgeon's ability to visualize the surgical target site, instruments and/or implants during the given surgical procedure. According to one embodiment, this mechanism may comprise, but need not be limited to, providing one or more strands of fiber optic cable within the walls of the retractor blades such that the terminal (distal) ends are capable of emitting light at or near the surgical target site. According to another embodiment, this mechanism may comprise, but need not be limited to, constructing the retractor blades of suitable material (such as clear polycarbonate) and configuration such that light may be transmitted generally distally through the walls of the retractor blade light to shine light at or near the surgical target site. This may be performed by providing the retractor blades having light-transmission characteristics (such as with clear polycarbonate construction) and transmitting the light almost entirely within the walls of the retractor blade (such as by frosting or otherwise rendering opaque portions of the exterior and/or interior) until it exits a portion along the interior (or medially-facing) surface of the retractor blade to shine at or near the surgical target site. The exit portion may be optimally configured such that the light is directed towards the approximate center of the surgical target site and may be provided along the entire inner periphery of the retractor blade or one or more portions therealong. BRIEF DESCRIPTION OF THE DRAWINGS Many advantages of the present invention will be apparent to those skilled in the art with a reading of this specification in conjunction with the attached drawings, wherein like reference numerals are applied to like elements and wherein: FIG. 1 is a perspective view of a tissue retraction assembly (in use) forming part of a surgical access system according to the present invention; FIG. 2 is a perspective view illustrating the components and use of an initial distraction assembly (i.e. K-wire, an initial dilating cannula with handle, and a split-dilator housed within the initial dilating cannula) forming part of the surgical access system according to the present invention, for use in distracting to a surgical target site (i.e. annulus); FIG. 3 is a perspective view illustrating the K-wire and split-dilator of the initial distraction assembly with the initial dilating cannula and handle removed; FIG. 4 is a posterior view of the vertebral target site illustrating the split-dilator of the present invention in use distracting in a generally cephalad-caudal fashion according to one aspect of the present invention; FIG. 5 is a side view illustrating the use of a secondary distraction assembly (comprising a plurality of dilating cannulae over the K-wire) to further distract tissue between the skin of the patient and the surgical target site according to the present invention; FIG. 6 is a perspective view of a retractor assembly according to the present invention, comprising a linkage assembly having three (3) retractor blades coupled thereto (posterior, cephalad, and caudal) for the purpose of creating an operative corridor to the surgical target site (shown in a first, closed position); FIG. 7 is a perspective view of the retractor assembly of FIG. 6 in a second, opened (i.e. retracted) position according to the present invention; FIG. 8 is a perspective view illustrating a shim introducer introducing a shim element along the interior of the posterior retractor blade such that a distal portion (shim extension) is positioned within the disc space; FIG. 9 is a back view of a shim element according to the present invention dimensioned to be engaged with the inner surface of the posterior (and optionally anterior) retractor blade for the purpose of positioning a shim extension within the disc space, such as via the shim introducer shown in FIG. 8; FIG. 10 is a perspective view of the retractor assembly of the present invention with the shim element disposed along the posterior retractor blade according to the present invention; FIGS. 11-12 are perspective views of the retractor assembly of the present invention, wherein an anterior retractor blade is provided coupled to the linkage assembly via an arm assembly; FIG. 13 is a perspective view of the retractor assembly of the present invention wherein a shim introducer is employed to introducer a shim along the anterior retractor blade according to the present invention; FIG. 14 is a perspective view of the retractor assembly of the present invention, wherein the anterior retractor blade may be positioned at a different vertical level than the posterior, cephalad, and caudal retractor blades according to the present invention; FIG. 15 is a perspective view of an exemplary nerve monitoring system capable of performing nerve monitoring before, during and after the creating of an operative corridor to a surgical target site using the surgical access system in accordance with the present invention; FIG. 16 is a block diagram of the nerve monitoring system shown in FIG. 15; and FIGS. 17-18 are screen displays illustrating exemplary features and information communicated to a user during the use of the nerve monitoring system of FIG. 15. DESCRIPTION OF THE PREFERRED EMBODIMENT Illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. It is furthermore to be readily understood that, although discussed below primarily within the context of spinal surgery, the surgical access system of the present invention may be employed in any number of anatomical settings to provide access to any number of different surgical target sites throughout the body. The surgical access system disclosed herein boasts a variety of inventive features and components that warrant patent protection, both individually and in combination. It is furthermore to be readily understood that, although discussed below primarily within the context of spinal surgery, the surgical access system and related methods of the present invention may find applicability in any of a variety of surgical and/or medical applications such that the following description relative to the spine is not to be limiting of the overall scope of the present invention. Moreover, while described below employing the nerve monitoring features described above (otherwise referred to as “nerve surveillance”) during spinal surgery, it will be appreciated that such nerve surveillance will not be required in all situations, depending upon the particular surgical target site (e.g. disk space, vertebral body, and/or internal organ), surgical approach (e.g. lateral, posterior, anterior, and/or postero-lateral approaches to the spine), and spinal level (e.g. cervical, thoracic and/or lumbar). The present invention is directed at a novel surgical access system and related methods which involve creating and maintaining an operative corridor to the surgical target site, and optionally detecting the existence of (and optionally the distance and/or direction to) neural structures before, during and/or after this process (including the steps of distraction and/or retraction). This is accomplished by employing the following steps: (1) one or more stimulation electrodes are provided on the various distraction and/or retraction components; (2) a stimulation source (e.g. voltage or current) is coupled to the stimulation electrodes; (3) a stimulation signal is emitted from the stimulation electrodes as the various components are advanced towards or maintained at or near the surgical target site; and (4) the patient is monitored to determine if the stimulation signal causes muscles associated with nerves or neural structures within the tissue to innervate. If the nerves innervate, this may indicate that neural structures may be in close proximity to the distraction and/or retraction components. Neural monitoring may be accomplished via any number of suitable fashions, including but not limited to observing visual twitches in muscle groups associated with the neural structures likely to found in the tissue, as well as any number of monitoring systems, including but not limited to any commercially available “traditional” electromyography (EMG) system (that is, typically operated by a neurophysiologist. Such monitoring may also be carried out via the surgeon-driven EMG monitoring system shown and described in the following commonly owned and co-pending “NeuroVision Applications” incorporated by reference into this disclosure above. In any case (visual monitoring, traditional EMG and/or surgeon-driven EMG monitoring), the access system of the present invention may advantageously be used to traverse tissue that would ordinarily be deemed unsafe or undesirable, thereby broadening the number of manners in which a given surgical target site may be accessed. Distraction followed by retraction is advantageous because it provides the ability to more easily position an operative corridor-establishing device through tissue that is strong, thick or otherwise challenging to traverse in order to access a surgical target site. The various distraction systems of the present invention are advantageous in that they provide an improved manner of atraumatically establishing a distraction corridor prior to the use of the retraction systems of the present invention. The various retractor systems of the present invention are advantageous in that they provide an operative corridor having improved cross-sectional area and shape (including customization thereof) relative to the prior art surgical access systems. Moreover, by optionally equipping the various distraction systems and/or retraction systems with one or more electrodes, an operative corridor may be established through (or near) any of a variety of tissues having such neural structures which, if contacted or impinged, may otherwise result in neural impairment for the patient. The present invention involves accessing a surgical target site in a fashion less invasive than traditional “open” surgeries and doing so in a manner that provides access in spite of the neural structures required to be passed through (or near) in order to establish an operative corridor to the surgical target site. Generally speaking, the surgical access system of the present invention accomplishes this by providing a tissue distraction assembly and a tissue retraction assembly, both of which may be equipped with one or more electrodes for use in detecting the existence of (and optionally the distance and/or direction to) neural structures. These electrodes are preferably provided for use with a nerve surveillance system such as, by way of example, the type shown and described in co-pending and commonly assigned NeuroVision PCT Applications incorporated by reference above. Generally speaking, this nerve surveillance system is capable of detecting the existence of (and optionally the distance and/or direction to) neural structures during the distraction and retraction of tissue by detecting the presence of nerves by applying a stimulation signal to such instruments and monitoring the evoked EMG signals from the myotomes associated with the nerves being passed by the distraction and retraction systems of the present invention. In so doing, the system as a whole (including the surgical access system of the present invention) may be used to form an operative corridor through (or near) any of a variety of tissues having such neural structures, particularly those which, if contacted or impinged, may otherwise result in neural impairment for the patient. In this fashion, the access system of the present invention may be used to traverse tissue that would ordinarily be deemed unsafe or undesirable, thereby broadening the number of manners in which a given surgical target site may be accessed. The tissue distraction assembly of the present invention (comprising a K-wire, an initial dilator, and a split-dilator disposed within the initial dilator) is employed to distract the tissues extending between the skin of the patient and a given surgical target site (preferably along the posterior region of the target intervertebral disc). A secondary distraction assembly (i.e. a plurality of sequentially dilating cannulae) may optionally be employed after the initial distraction assembly to further distract the tissue. Once distracted, the resulting void or distracted region within the patient is of sufficient size to accommodate a tissue retraction assembly of the present invention. More specifically, the tissue retraction assembly (comprising a plurality of retractor blades coupled to a linkage assembly) may be advanced relative to the secondary distraction assembly such that the retractor blades, in a first, closed position, are advanced over the exterior of the secondary distraction assembly. At that point, the linkage assembly may be operated to move the retractor blades into a second, open or “retracted” position to create an operative corridor to the surgical target site. According to one aspect of the invention, following (or before) this retraction, a posterior shim element (which is preferably slideably engaged with the posterior retractor blade) may be advanced such that a shim extension in positioned within the posterior region of the disc space. If done before retraction, this helps ensure that the posterior retractor blade will not move posteriorly during the retraction process, even though the other retractor blades (i.e. cephalad, caudal, and/or anterior retractor blades) are able to move and thereby create an operative corridor. Fixing the posterior retractor blade in this fashion helps prevent inadvertent contact with the existing nerve roots in the posterior region of the spine. The posterior shim element also helps ensure that surgical instruments employed within the operative corridor are incapable of being advanced outside the operative corridor, yet again preventing inadvertent contact with the exiting nerve roots during the surgery. Once in the appropriate anterior position, the anterior retractor blade may be locked in position and, thereafter, an anterior shim element advanced therealong for positioning a shim extension within the anterior of the disc space. The shim elements serve to distract the adjacent vertebral bodies (thereby restoring disc height), to form protective barriers (against the migration of tissue into (or instruments out of) the operative site), and to rigidly couple the posterior and anterior retractor blades in fixed relation relative to the vertebral bodies. Once the operative corridor is established, any of a variety of surgical instruments, devices, or implants may be passed through and/or manipulated within the operative corridor depending upon the given surgical procedure. FIG. 1 illustrates a tissue retraction assembly 10 forming part of a surgical access system according to the present invention. The retraction assembly 10 includes a posterior retractor blade 12, an anterior retractor blade 14, cephalad retractor blade 16, and caudal retractor blade 18, all of which are coupled to a linkage assembly 20. Posterior and anterior retractor blades 12, 14 establish an AP (or “width”) dimension of an operative corridor 15. Posterior retractor blade 12 and anterior retractor blade 14 are equipped with shim elements 22, 24, respectively (shown more clearly-in FIG. 9). Shim-elements 22, 24 serve to distract the adjacent vertebral bodies (thereby restoring disc height), form protective barriers (against the migration of tissue into (or instruments out of) the operative site), and rigidly couple the posterior and anterior retractor blades 12, 14 in fixed relation relative to the vertebral bodies. Cephalad and caudal retractor blades 16, 18 establish and maintain the “height” dimension of the operative corridor 15. Each retractor blade 12-18 (and optionally the shim elements 22, 24) may be, according to the present invention, provided with one or more electrodes 39 (preferably at their distal regions) equipped for use with a nerve surveillance system, such as, by way of example, the type shown and described in the NeuroVision PCT Applications. The linkage assembly 20 may be coupled to any number of mechanisms for rigidly registering the linkage assembly 20 in fixed relation to the operative site, such as through the use of an articulating arm mounted to the operating table. The linkage assembly 20 includes first and second arm members 26, 28 hingedly coupled at 30. The cephalad retractor blade 16 is rigidly coupled (generally perpendicularly) to the end of the first arm member 26. The caudal retractor blade 18 is rigidly coupled (generally perpendicularly) to the end of the second arm member 28. The posterior retractor blade 12 is coupled to the linkage assembly 20 via a pivot linkage 32 (comprising a first arm 34 hingedly disposed between the posterior retractor blade 12 and the first arm member 26, and a second arm 26 hingedly disposed between the posterior retractor blade 12 and the second arm 28) such that the posterior retractor blade 12 will have a tendency to remain in the same position during the retraction process. According to one embodiment, the anterior retractor blade 14 may be coupled to the linkage assembly 20 via an arm assembly 38. FIG. 2 illustrates an initial distraction assembly 40 forming part of the surgical access system according to the present invention. The initial distraction assembly 40 includes a K-wire 42, an initial dilating cannula 44 with handle 46, and a split-dilator 48 housed within the initial dilating cannula 44. In use, the K-wire 42 and split-dilator 48 are disposed within the initial dilating cannula 44 and the entire assembly 40 advanced through the tissue towards the surgical target site (i.e. annulus). Again, this is preferably accomplished while employing the nerve detection and/or direction features described above. After the initial dilating assembly 40 is advanced such that the distal ends of the split-dilator 48 and initial dilator 44 are positioned within the disc space (FIG. 2), the initial dilator 44 and handle 46 are removed (FIG. 3) to thereby leave the split-dilator 48 and K-wire 42 in place. As shown in FIG. 4, the split-dilator 48 is thereafter split such that the respective halves 48a, 48b are separated from one another to distract tissue in a generally cephalad-caudal fashion relative to the target site. The split dilator 48 may thereafter be relaxed (allowing the dilator halves 48a, 48b to come together) and rotated such that the dilator halves 48a, 48b are disposed in the anterior-posterior plane. Once rotated in this manner, the dilator halves 48a, 48b are again separated to distract tissue in a generally anterior-posterior fashion. Each dilator halve 48a, 48b may be, according to the present invention, provided with one or more electrodes (preferably at their distal regions) equipped for use with a nerve surveillance system, such as, by way of example, the type shown and described in the NeuroVision PCT Applications. Following this initial distraction, a secondary distraction may be optionally undertaken, such as via a sequential dilation system 50 as shown in FIG. 5. According to the present invention, the sequential dilation system 50 may include the K-wire 42, the initial dilator 44, and one or more supplemental dilators 52, 54 for the purpose of further dilating the tissue down to the surgical target site. Once again, each component of the secondary distraction assembly 50 (namely, the K-wire 42, the initial dilator 44, and the supplemental dilators 52, 54 may be, according to the present invention, provided with one or more electrodes (preferably at their distal regions) equipped for use with a nerve surveillance system, such as, by way of example, the type shown and described in the NeuroVision PCT Applications. As shown in FIG. 6, the retraction assembly 10 of the present invention is thereafter advanced along the exterior of the sequential dilation system 50. This is accomplished by maintaining the retractor blades 12-16 in a first, closed position (with the retractor blades 12-16 in generally abutting relation to one another). Once advanced to the surgical target site, the linkage assembly 20 may be operated as shown in FIG. 7 to move the retractor blades 12-16 into a second, open or “retracted” position. As one can see, the posterior retractor blade 12 is allowed to stay in the same general position during this process, such that the cephalad and caudal retractor blades 14, 16 move away from the posterior retractor blade 12. Again, this is accomplished through the use of the pivot linkage 32 between the posterior retractor blade 12 and the arms 26, 28 of the linkage assembly 20. At this point, as shown in FIG. 8, the posterior shim element 22 (FIG. 9) may be advanced along an engagement slot formed along the interior surface of the posterior retractor blade 12 such that the shim extension (distal end) is positioned in the posterior region of the disc space as shown in FIG. 10. To aid in this process, a shim introducer 60 may be provided, which includes a handle member 62 and an elongate portion 64 capable of delivering the shim element 22 along the interior of the posterior retractor blade 12 and thereafter selectively disengaging the shim element 22 so as to remove the elongate portion 64 from the operative site. As shown in FIGS. 11-12, the anterior retractor blade 14 may thereafter be positioned relative to the posterior, cephalad, and caudal retractor blades 12, 16, 18, respectively, by virtue of the arm assembly 38. The anterior shim element 24 may thereafter be advanced along the anterior retractor blade 14 such that the shim extension (distal region thereof) extends into the anterior region of the disc space as shown in FIG. 13. The end result is shown in FIG. 14, with the retraction assembly 10 of the present invention disposed in position over a surgical target site. FIGS. 15-16 illustrate, by way of example only, a surgical system 120 provided in accordance with a broad aspect of the present invention. The surgical system 120 includes a control unit 122, a patient module 124, an EMG harness 126 and return electrode 128 coupled to the patient module 124, and an accessory cable 132 in combination with a handle assembly 136. The handle assembly 136 includes one or more electrical connectors 130, including (by way of example only) a pin connector 134, a pin connector 138, and a clamping-style connector 135. As shown in dotted lines, each of the electrical connectors 130 may be coupled to the handle assembly 136 and include a manner of establishing electrical communications with any of the electrodes 39 provided-on the distraction and/or retraction assemblies of the present invention, including the shims 22, 24 (collectively “Surgical Access Instruments”). By establishing electrical communication in this fashion, the handle assembly 136 may be employed to selectively apply a stimulation signal to any of the Surgical Access Instruments to detect the presence of (and optionally direction to) neural structures during and/or after the distraction and retraction steps of the present invention. The control unit 122 includes a touch screen display 140 and a base 142, which collectively contain the essential processing capabilities for controlling the surgical system 120. The patient module 124 is connected to the control unit 122 via a data cable 144, which establishes the electrical connections and communications (digital and/or analog) between the control unit 122 and patient module 124. The main functions of the control unit 122 include receiving user commands via the touch screen display 140, activating stimulation, processing signal data according to defined algorithms (described below), displaying received parameters and processed data, and monitoring system status and reporting fault conditions. The touch screen display 140 is preferably equipped with a graphical user interface (GUI) capable of communicating information to the user and receiving instructions from the user. The display 140 and/or base 142 may contain patient module interface circuitry that commands the stimulation sources, receives digitized signals and other information from the patient module 124, processes the EMG responses to extract characteristic information for each muscle group, and displays the processed data to the operator via the display 140. The accessory handle assembly 136 includes a cable 155 for establishing electrical communication with the patient module 124 (via the accessory cable 132). In a preferred embodiment, each electrical connector 130 includes a proximal electrical connector 156 and an electrical cable 157 for establishing electrical communication between the handle assembly 136 and the electrical connectors 134, 138, and 135. The proximal electrical connector 156 may be designed to thread and/or snap into engagement with the distal end 159 of the handle assembly 136. In this fashion, the Surgical Access Instruments may be quickly and easily coupled (electrically and mechanically) to the accessory handle assembly 136. The pin connectors 134 and 138 may be designed to engage with electrical mating portions provided on the Surgical Access Instruments, wherein these electrical mating portions are in turn electrically coupled to the electrodes 39. The distal electrical connector of the clamp-type coupler 135 may include any number of suitable electrode or electrode regions (including protrusions) on or about the distal (or pinching) ends of the clamp arms 161 forming the coupler 135. Corresponding regions (such as electrodes or electrode regions—including indentations) may be provided on the Surgical Access Instruments (including K-wire 42) according to the present invention. In all situations, the user may operate one or more buttons of the handle assembly 136 to selectively initiate a stimulation signal (preferably, a current signal) from the patient module 124 to one of the electrical connectors 130, and hence the electrodes 39 on the distraction and retraction assemblies of the present invention. By monitoring the myotomes associated with the nerve roots (via the EMG harness 126 and recording electrode 127) and assessing the resulting EMG responses (via the control unit 122), the surgical system 120 can detect the presence of (and optionally the direction to) neural structures during and after the distraction and/or retraction according to the present invention. In one embodiment, the monitoring system 120 is capable of determining nerve presence and/or direction relative to one or more of the K-wire 42, dilating cannula 44, split-retractor 48, retractor blades 12-18, and/or the shim elements 22, 24 before, during and/or following the creation of an operative corridor to a surgical target site. Monitoring system 120 accomplishes this by having the control unit 122 and patient module 124 cooperate to send electrical stimulation signals to one or more of the stimulation electrodes provided on these Surgical Access Instruments. Depending upon the location within a patient (and more particularly, to any neural structures), the stimulation signals may cause nerves adjacent to or in the general proximity of the Surgical Access Instruments to depolarize. This causes muscle groups to innervate and generate EMG responses, which can be sensed via the EMG harness 126. The nerve direction feature of the system 120 is based on assessing the evoked response of the various muscle myotomes monitored by the system 120 via the EMG harness 126. By monitoring the myotomes associated with the nerves (via the EMG harness 126 and recording electrode 127) and assessing the resulting EMG responses (via the control unit 122), the surgical access system of the present invention is capable of detecting the presence of (and optionally the distant and/or direction to) such nerves. This provides the ability to actively negotiate around or past such nerves to safely and reproducibly form the operative corridor to a particular surgical target site, as well as monitor to ensure that no neural structures migrate into contact with the retraction assembly 10 after the operative corridor has been established. In spinal surgery, for example, this is particularly advantageous in that the surgical access system of the present invention may be particularly suited for establishing an operative corridor to an intervertebral target site in a postero-lateral, trans-psoas fashion so as to avoid the bony posterior elements of the spinal column. FIGS. 17-18 are exemplary screen displays (to be shown on the display 140) illustrating one embodiment of the nerve direction feature of the monitoring system shown and described with reference to FIGS. 15-16. These screen displays are intended to communicate a variety of information to the surgeon in an easy-to-interpret fashion. This information may include, but is not necessarily limited to, a display of the function 180 (in this case “DIRECTION”), a graphical representation of a patient 181, the myotome levels being monitored 182, the nerve or group associated with a displayed myotome 183, the name of the instrument being used 184 (e.g. dilating cannula 44), the size of the instrument being used 185, the stimulation threshold current 186, a graphical representation of the instrument being used 187 (in this case, a cross-sectional view of a dilating cannula 44) to provide a reference point from which to illustrate relative direction of the instrument to the nerve, the stimulation current being applied to the stimulation electrodes 188, instructions for the user 189 (in this case, “ADVANCE” and/or “HOLD”), and (in FIG. 19) an arrow 190 indicating the direction from the instrument to a nerve. This information may be communicated in any number of suitable fashions, including but not limited to the use of visual indicia (such as alpha-numeric characters, light-emitting elements, and/or graphics) and audio communications (such as a speaker element). Although shown with specific, reference to a dilating cannula (such as at 184), it is to be readily appreciated that the present invention is deemed to include providing similar information on the display 140 during the use of any or all of the various Surgical Access Instruments of the present invention, including the initial distraction assembly 40 (i.e. the K-wire 42, dilating cannula 44, and split dilator 48), the secondary distraction assembly 50, and/or the retractor blades 12-18 and/or shim elements 22, 24 of the retraction assembly 10. The retractor blades 12-18 and the shim elements 22, 24 of the present invention may also be provided with one or more electrodes for use in providing the neural monitoring capabilities of the present invention. By way of example only, it may be advantageous to provide one or more electrodes on these components (preferably on the side facing away from the surgical target site) for the purpose of conducting neural monitoring before, during and/or after the retractor blades 12-18 and/or shim elements 22, 24 have been positioned at or near the surgical target site. The surgical access system of the present invention may be sold or distributed to end users in any number of suitable kits or packages (sterile and/or non-sterile) containing some or all of the various components described herein. For example, the retraction assembly 10 may be provided such that the mounting assembly 20 is reusable (e.g., autoclavable), while the retractor blades 12-18 and/or shim elements 22, 24 are disposable. In a further embodiment, an initial kit may include these materials, including a variety of sets of retractor blades 12-18 and/or shim elements 22, 24 (and extensions 80) having varying (or “incremental”) lengths to account for surgical target sites of varying locations within the patient, optionally color-coded to designate a predetermined length. As evident from the above discussion and drawings, the present invention accomplishes the goal of providing a novel surgical access system and related methods which involve creating a distraction corridor to a surgical target site, thereafter retracting the distraction corridor to establish and maintain an operative corridor to the surgical target site, and optionally detecting the existence of (and optionally the distance and/or direction to) neural structures before, during and/or after the formation of the distraction and/or operative corridors. The surgical access system of the present invention can be used in any of a wide variety of surgical or medical applications, above and beyond the spinal applications discussed herein. By way of example only, in spinal applications, any number of implants and/or instruments may be introduced through the working cannula 50, including but not limited to spinal fusion constructs (such as allograft implants, ceramic implants, cages, mesh, etc.), fixation devices (such as pedicle and/or facet screws and related tension bands or rod systems), and any number of motion-preserving devices (including but not limited to nucleus replacement and/or total disc replacement systems). While certain embodiments have been described, it will be appreciated by those skilled in the art that variations may be accomplished in view of these teachings without deviating from the spirit or scope of the present application. For example, with regard to the monitoring system 120, it may be implemented using any combination of computer programming software, firmware or hardware. As a preparatory act to practicing the system 120 or constructing an apparatus according to the application, the computer programming code (whether software or firmware) according to the application will typically be stored in one or more machine readable storage mediums such as fixed (hard) drives, diskettes, optical disks, magnetic tape, semiconductor memories such as ROMs, PROMs, etc., thereby making an article of manufacture in accordance with the application. The article of manufacture containing the computer programming code may be used by either executing the code directly from the storage device, by copying the code from the storage device into another storage device such as a hard disk, RAM, etc. or by transmitting the code on a network for remote execution. As can be envisioned by one of skill in the art, many different combinations of the above may be used and accordingly the present application is not limited by the scope of the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>I. Field of the Invention The present invention relates generally to systems and methods for performing surgical procedures and, more particularly, for accessing a surgical target site in order to perform surgical procedures. II. Discussion of the Prior Art A noteworthy trend in the medical community is the move away from performing surgery via traditional “open” techniques in favor of minimally invasive or minimal access techniques. Open surgical techniques are generally undesirable in that they typically require large incisions and high amounts of tissue displacement to gain access to the surgical target site, which produces concomitantly high amounts of pain, lengthened hospitalization (increasing health care costs), and high morbidity in the patient population. Less-invasive surgical techniques (including so-called “minimal access” and “minimally invasive” techniques) are gaining favor due to the fact that they involve accessing the surgical target site via incisions of substantially smaller size with greatly reduced tissue displacement requirements. This, in turn, reduces the pain, morbidity and cost associated with such procedures. The access systems developed to date, however, fail in various respects to meet all the needs of the surgeon population. One drawback associated with prior art surgical access systems relates to the ease with which the operative corridor can be created, as well as maintained over time, depending upon the particular surgical target site. For example, when accessing surgical target sites located beneath or behind musculature-or other relatively strong tissue (such as, by way of example only, the psoas muscle adjacent to the spine), it has been found that advancing an operative corridor-establishing instrument directly through such tissues can be challenging and/or lead to unwanted or undesirable effects (such as stressing or tearing the tissues). While certain efforts have been undertaken to reduce the trauma to tissue while creating an operative corridor, such as (by way of example only) the sequential dilation system of U.S. Pat. No. 5,792,044 to Foley et al., these attempts are nonetheless limited in their applicability based on the relatively narrow operative corridor. More specifically, based on the generally cylindrical nature of the so-called “working cannula,” the degree to which instruments can be manipulated and/or angled within the cannula can be generally limited or restrictive, particularly if the surgical target site is a relatively deep within the patient. Efforts have been undertaken to overcome this drawback, such as shown in U.S. Pat. No. 6,524,320 to DiPoto, wherein an expandable portion is provided at the distal end of a cannula for creating a region of increased cross-sectional area adjacent to the surgical target site. While this system may provide for improved instrument manipulation relative to sequential dilation access systems (at least at deep sites within the patient), it is nonetheless flawed in that the deployment of the expandable portion may inadvertently compress or impinge upon sensitive tissues adjacent to the surgical target site. For example, in anatomical regions having neural and/or vasculature structures, such a blind expansion may cause the expandable portion to impinge upon these sensitive tissues and cause neural and/or vasculature compromise, damage and/or pain for the patient. This highlights yet another drawback with the prior art surgical access systems, namely, the challenges in establishing an operative corridor through or near tissue having major neural structures which, if contacted or impinged, may result in neural impairment for the patient. Due to the threat of contacting such neural structures, efforts thus far have largely restricted to establishing operative corridors through tissue having little or substantially reduced neural structures, which effectively limits the number of ways a given surgical target site can be accessed. This can be seen, by way of example only, in the spinal arts, where the exiting nerve roots and neural plexus structures in the psoas muscle have rendered a lateral or far lateral access path (so-called trans-psoas approach) to the lumbar spine virtually impossible. Instead, spine surgeons are largely restricted to accessing the spine from the posterior (to perform, among other procedures, posterior lumbar interbody fusion (PLWF)) or from the anterior (to perform, among other procedures, anterior lumbar interbody fusion (ALIF)). Posterior-access procedures involve traversing a shorter distance within the patient to establish the operative corridor, albeit at the price of oftentimes having to reduce or cut away part of the posterior bony structures (i.e. lamina, facets, spinous process) in order to reach the target site (which typically comprises the disc space). Anterior-access procedures are relatively simple for surgeons in that they do not involve reducing or cutting away bony structures to reach the surgical target site. However, they are nonetheless disadvantageous in that they require traversing through a much greater distance within the patient to establish the operative corridor, oftentimes requiring an additional surgeon to assist with moving the various internal organs out of the way to create the operative corridor. The present invention is directed at eliminating, or at least minimizing the effects of, the above-identified drawbacks in the prior art. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention accomplishes this goal by providing a novel access system and related methods which, according to one embodiment, involves detecting the existence of (and optionally the distance and/or direction to) neural structures before, during, and after the establishment of an operative corridor through (or near) any of a variety of tissues having such neural structures which, if contacted or impinged, may otherwise result in neural impairment for the patient. It is expressly noted that, although described herein largely in terms of use in spinal surgery, the access system of the present invention is suitable for use in any number of additional surgical procedures wherein tissue having significant neural structures must be passed through (or near) in order to establish an operative corridor. The present invention accomplishes this goal by providing a novel access system and related methods which involve: (1) distracting the tissue between the patient's skin and the surgical target site to create an area of distraction (otherwise referred to herein as a “distraction corridor”); (2) retracting the distraction corridor to establish and maintain an operative corridor; and/or (3) detecting the existence of (and optionally the distance and/or direction to) neural structures before, during and after the establishment of the operative corridor through (or near) any of a variety of tissues having such neural structures which, if contacted or impinged, may otherwise result in neural impairment for the patient. As used herein, “distraction” or “distracting” is defined as the act of creating a corridor (extending to a location at or near the surgical target site) having a certain cross-sectional area and shape (“distraction corridor”), and “retraction” or “retracting” is defined as the act of creating an operative corridor by increasing or maintaining the cross-sectional area of the distraction corridor (and/or modifying its shape) with at least one retractor blade such that surgical instruments can be passed through operative corridor to the surgical target site. According to one broad aspect of the present invention, the access system comprises a tissue distraction assembly and a tissue retraction assembly, both of which may be equipped with one or more electrodes for use in detecting the existence of (and optionally the distance and/or direction to) neural structures during the steps tissue distraction and/or retraction. To accomplish this, one or more stimulation electrodes are provided on the various components of the distraction assemblies and/or retraction assemblies, a stimulation source (e.g. voltage or current) is coupled to the stimulation electrodes, a stimulation signal is emitted from the stimulation electrodes as the various components are advanced towards the surgical target site, and the patient is monitored to determine if the stimulation signal causes muscles associated with nerves or neural structures within the tissue to innervate. If the nerves innervate, this indicates that neural structures may be in close proximity to the distraction and/or retraction assemblies. This monitoring may be accomplished via any number of suitable fashions, including but not limited to observing visual twitches in muscle groups associated with the neural structures likely to found in the tissue, as well as any number of monitoring systems. In either situation (traditional EMG or surgeon-driven EMG monitoring), the access system of the present invention may advantageously be used to traverse tissue that would ordinarily be deemed unsafe or undesirable, thereby broadening the number of manners in which a given surgical target site may be accessed. The tissue distraction assembly is capable of, as an initial step, distracting a region of tissue between the skin of the patient and the surgical target site. The tissue retraction assembly is capable of, as a secondary step, being introduced into this distracted region to thereby define and establish the operative corridor. Once established, any of a variety of surgical instruments, devices, or implants may be passed through and/or manipulated within the operative corridor depending upon the given surgical procedure. The electrode(s) are capable of, during both tissue distraction and retraction, detecting the existence of (and optionally the distance and/or direction to) neural structures such that the operative corridor may be established through (or near) any of a variety of tissues having such neural structures which, if contacted or impinged, may otherwise result in neural impairment for the patient. In this fashion, the access system of the present invention may be used to traverse tissue that would ordinarily be deemed unsafe or undesirable, thereby broadening the number of manners in which a given surgical target site may be accessed. The tissue distraction assembly may include any number of components capable of performing the necessary distraction. By way of example only, the tissue distraction assembly may include a K-wire, an initial dilator (of split construction or traditional non-slit construction), and one or more dilators of traditional (that is, non-split) construction for performing the necessary tissue distraction to receive the remainder of the tissue retractor assembly thereafter. One or more electrodes may be provided on one or more of the K-wire and dilator(s) to detect the presence of (and optionally the distance and/or direction to) neural structures during tissue distraction. The tissue retraction assembly may include any number of components capable of performing the necessary retraction. By way of example only, the tissue retraction assembly may include one or more retractor blades extending proximally from the surgical target site for connection with a pivot linkage assembly. The pivot linkage includes first and second pivot arms capable of maintaining the retractor blades in a first, closed position to facilitate the introduction of the retractor blades over the distraction assembly. Thereafter, the pivot linkage may be manipulated to open the retractor assembly; that is, allowing the retractor blades to separate from one another (preferably simultaneously) to create an operative corridor to the surgical target site. In a preferred embodiment, this is accomplished by maintaining a posterior retractor blade in a fixed position relative to the surgical target site (so as to avoid having it impinge upon any exiting nerve roots near the posterior elements of the spine) while the additional retractor blades (i.e. cephalad, caudal and/or anterior retractor blades) are moved or otherwise translated away from the posterior retractor blade (and each other) so as to create the operative corridor in a fashion that doesn't infringe upon the region of the exiting nerve roots. This is accomplished, in part, through the use of a secondary pivot linkage coupled to the pivot linkage assembly, which allows the posterior retractor blade to remain in a constant position while the other retractor blades are moved. In one embodiment, the anterior retractor blade may be positioned after the posterior, cephalad, and caudal retractor blades are positioned into the fully retracted position. This may be accomplished by coupling the anterior retractor blade to the pivot linkage via an arm assembly. The retractor blades may be optionally dimensioned to receive and direct a rigid shim element to augment the structural stability of the retractor blades and thereby ensure the operative corridor, once established, will not decrease or become more restricted, such as may result if distal ends of the retractor blades were permitted to “slide” or otherwise move in response to the force exerted by the displaced tissue. In a preferred embodiment, only the posterior and anterior retractor blades are equipped with such rigid shim elements, which are advanced into the disc space after the posterior and anterior retractor blades are positioned (posterior first, followed by anterior after the cephalad, caudal and anterior blades are moved into the fully retracted position). The rigid shim elements are preferably oriented within the disc space such that they distract the adjacent vertebral bodies, which serves to restore disc height. They are also preferably advanced a sufficient distance within the disc space (preferably past the midline), which serves the dual purpose of preventing post-operative scoliosis and forming a protective barrier (preventing the migration of tissue (such as nerve roots) into the operative field and the inadvertent advancement of instruments outside the operative field). The retractor blades may optionally be equipped with a mechanism for transporting or emitting light at or near the surgical target site to aid the surgeon's ability to visualize the surgical target site, instruments and/or implants during the given surgical procedure. According to one embodiment, this mechanism may comprise, but need not be limited to, providing one or more strands of fiber optic cable within the walls of the retractor blades such that the terminal (distal) ends are capable of emitting light at or near the surgical target site. According to another embodiment, this mechanism may comprise, but need not be limited to, constructing the retractor blades of suitable material (such as clear polycarbonate) and configuration such that light may be transmitted generally distally through the walls of the retractor blade light to shine light at or near the surgical target site. This may be performed by providing the retractor blades having light-transmission characteristics (such as with clear polycarbonate construction) and transmitting the light almost entirely within the walls of the retractor blade (such as by frosting or otherwise rendering opaque portions of the exterior and/or interior) until it exits a portion along the interior (or medially-facing) surface of the retractor blade to shine at or near the surgical target site. The exit portion may be optimally configured such that the light is directed towards the approximate center of the surgical target site and may be provided along the entire inner periphery of the retractor blade or one or more portions therealong. | 20040116 | 20100406 | 20080424 | 98242.0 | A61B132 | 1 | PATEL, YOGESH P | SURGICAL ACCESS SYSTEM AND RELATED METHODS | UNDISCOUNTED | 0 | ACCEPTED | A61B | 2,004 |
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10,759,954 | ACCEPTED | Method and apparatus for improving the magnitude of compressive stress developed in the surface of a part | This invention relates to a method and an apparatus for performing the method of inducing compressive residual stress along the surface of a part. In the preferred embodiment of the invention, the method includes burnishing or deep rolling a surface using a first and a second roller or ball burnishing members, whereby the first and second burnishing members may have a different diameter and/or modulus of elasticity. In another preferred embodiment of the invention, the burnishing operations may be performed while the surface of the part is at different temperatures. | 1. A method of inducing residual compressive stresses in the surface of a part comprising the steps of: performing a first operation to induce deep compressive surface stresses along a portion of the surface of the part; and performing a second operation to induce more shallow compressive surfaces stresses along a portion of the surface of the part. 2. The method of claim 1 wherein the first operation is performed with an apparatus for inducing residual compressive stresses comprising a burnishing member having a first diameter and the second operation is performed with a burnishing member having a second diameter. 3. The method of claim 1 wherein the second operation is performed in more than one pass. 4. The method of claim 1 wherein the operations are performed in a single pass of the apparatus. 5. The method of claim 1 whereby the operations are performed using single point burnishing members. 6. The method of claim 1 wherein the temperature of the surface of the part during the first operation is of a first temperature and the temperature of the surface of the part during the second operation is of a second different temperature. 7. The method of claim 1 wherein the first and the second operations are performed using burnishing members and the modulus of elasticity of the burnishing member performing the first operation is different than the modulus of elasticity performing the second operation. 8. The method of claim 1 wherein the first and second operations are performed such that the amount of surface cold working is less than about 5.0 percent. 9. The method of claim 1 wherein the first and second operations are performed such that the amount of surface cold working is less than about 2.0 percent. 10. The method of claim 1 wherein the desired layer of compressive residual stress to be induced within the surface of the part is determined using x-ray diffraction techniques. 11. A method of inducing residual compressive stresses in the surface of a part comprising the steps of: selecting at least one region along the surface of the part for inducing a first layer of compressive stresses within the surface of the part; performing a first burnishing operation using a first burnishing member to induce a first layer of compressive surface stresses along a selected region of the part; and performing a second burnishing operation using a second burnishing member to induce a second layer of compressive surfaces stresses along a selected region of the part; wherein said first burnishing member has a first diameter and said second burnishing member having a second different diameter. 12. The method of claim 11 wherein the modulus of elasticity of the burnishing member performing the first burnishing operation is different than the modulus of elasticity performing the second burnishing operation. 13. The method of claim 11 wherein the temperature of the surface of the part during the first burnishing operation is of a first temperature and the temperature of the surface of the part during the second burnishing operation is of a second different temperature. 14. A method of inducing residual compressive stresses in the surface of a part comprising the steps of: selecting at least one region along the surface of the part for inducing a first layer of compressive stresses within the surface of the part; performing a first burnishing operation using a first burnishing member to induce a first layer of compressive surface stresses along a selected region of the part; and performing a second burnishing operation using a second burnishing member to induce a second layer of compressive surfaces stresses along a selected region of the part; wherein the first burnishing operation is performed when the temperature of the surface is at a first temperature and the second burnishing operation is performed when the temperature of the surface is at a temperature different than the first temperature. 15. A method of inducing residual compressive stresses in the surface of a part comprising the steps of: selecting at least one region along the surface of the part for inducing a first layer of compressive stresses within the surface of the part; performing a first burnishing operation using a first burnishing member to induce a first layer of compressive surface stresses along a selected region of the part; and performing a second burnishing operation using a second burnishing member to induce a second layer of compressive surfaces stresses along a selected region of the part; wherein said first burnishing member has a modulus of elasticity that is different than the modulus of elasticity of said second burnishing member. 16. An apparatus for inducing a layer of compressive residual stress within the surface of a part comprising a first burnishing member and a second burnishing member; wherein said first burnishing member has a first diameter and said second burnishing member having a second different diameter. 17. The method of claim 16 wherein the apparatus comprises a plurality of burnishing members of consecutively smaller diameters. 18. The apparatus of claim 16 wherein said first burnishing member is fixed in a first positioning device and said second burnishing member is fixed in a second positioning device. 19. The apparatus of claim 16 wherein said first burnishing member and said second burnishing member are fixed in a single positioning device. 20. The apparatus of claim 16 wherein the modulus of elasticity of the said first burnishing member is different than the modulus of elasticity of said second burnishing member. | BACKGROUND OF THE INVENTION This invention relates to a method and an apparatus for performing the method of inducing compressive residual stress along the surface of a part and, more particularly, to a method and an apparatus for performing the method of burnishing or deep rolling a surface of a part whereby the magnitude and penetration of compressive residual stress achieved is greater than that achieved by conventional burnishing. Surface residual stresses are known to have a major affect upon the fatigue and stress corrosion performance of components or parts in service. Tensile residual stresses that can be developed during manufacturing processes, such as grinding, turning, or welding are well known to reduce both fatigue life and increase sensitivity to corrosion-fatigue and stress corrosion cracking in a wide variety of materials. It is also known that compressive residual stresses induced in the surface of a part can increase its fatigue life and reduce its susceptibility to corrosion-fatigue and stress corrosion cracking. However, the benefit of inducing a layer of surface compression in reducing susceptibility to stress corrosion, cracking, fatigue, and corrosion-fatigue is lost if the layer of compression relaxes with time in service. Many components and parts of practical interest are subject to high tensile cyclic loads or high mean loads that often lead to fatigue, corrosion fatigue, stress corrosion, or a combination of such failure modes. Therefore, it would be desirable to be able to introduce a layer of compressive residual stress along the surface of a part that will not relax significantly over time. A method that has been developed and is widely used in industry to improve surface finish as well as fatigue life and corrosion resistance of a part by inducing a layer of compressive residual stress along its surface of the part is known as burnishing. During the burnishing process, the surface of a part is deformed by a rotary or sliding burnishing member that is pressed against the part in order to compress the microscopic peaks formed along the surface of the part into adjacent hollows. Burnishing thereby operates to develop compressive stresses by yielding the surface of the part in tension so that it returns to a state of compression following deformation. Burnishing tools comprising various wheel or roller burnishing member configurations have been developed for cold working a part and to induce a state of compressive stress and improved surface finish to the part. In addition, “deep rolling” and “low plasticity burnishing” processes have also been developed for producing deep layers of compressive stress that approach the yield strength of the material and which extend to over a millimeter into the surface. However, the deformation mechanism for producing such compressive stresses is based on hertzian loading and will generally produce maximum compression below the surface of the part. In many high strength or work hardening materials, the stresses produced along the upper surface by these burnishing methods can be far less than the subsurface maximum, often being close to or having zero compression at the upper surface. Processes have therefore been developed to increase the stress levels at the upper surface of a part. Such processes include removing a thin layer of material from the surface of the part, such as by etching, electropolishing, or some other non-tensile stress forming process; or a post treatment, such as shot peening, grit blasting, or similar compression producing treatments, to render the surface more highly compressive. Unfortunately, both approaches require a secondary surface treatment unrelated to the original burnishing process thereby adding time, cost, and the potential for damage and the loss of the part during manufacture. With respect to shot peening operations, secondary peening operations have been used to improve surface compression. For example, to increase the state of surface compression in a part, secondary peening operations have been performed using small glass or ceramic shot following conventional steel shot peening with larger shot. Shot peening while being relatively inexpensive and preferred for many applications, is often unable to obtain the necessary coverage of the part without overlaping areas of impingement. Such overlapping often results in relatively large amount of cold working which may leave the surface compressive layer susceptible to stress relaxation. Further, shot peening is often unacceptable for use in manufacturing parts requiring a superior finish, localized or relatively complex compressive stress zones or patterns, or requiring a greater depth of compressive stress penetration. Consequently, it would be desirable to have a relatively inexpensive and time efficient method and apparatus for implementing the method of improving the physical properties of a part by increasing the magnitude and penetration of compressive stress on the surface that would not significantly relax over time. It would also be desirable to have a method and an apparatus that would be effective for use with complex shaped surfaces and without detracting from the finish of the surface, and which could be performed relatively inexpensively and in a single pass. SUMMARY OF THE INVENTION The novel method of the present invention for inducing compressive stress on the surface of a part comprises the steps of selecting at least one region along the surface of the part for inducing compressive surface stresses; performing a first operation to induce compressive surface stresses along the selected region of the part; and performing a second operation to induce a second layer of compressive surface stresses along the selected region of the part. In another preferred embodiment of the invention the compressive surface stresses are induced into the selected region of the part by exerting compressive forces against the surface such that during the first operation the compressive force is greater than the compressive force exerted during the second operation. In another preferred embodiment of the invention the first operation and the second operation of inducing compressive residual stresses along the surface of the part are burnishing operations. In another preferred embodiment of the invention the burnishing operations are performed using a compression inducing means having a first burnishing member and a second burnishing member whereby the first burnishing member has a different modulus of elasticity than the second burnishing member. In another preferred embodiment of the invention, the diameter of the first burnishing member is smaller than the diameter of the second burnishing member. In another preferred embodiment of the invention the diameter of the first burnishing member is larger than the diameter of the second burnishing member. In another preferred embodiment of the invention, the method induces at least one layer of compressive residual stress along the selected region such that the amount of cold working of less than about 5%. In another preferred embodiment of the invention, the method induces at least one layer of compressive residual stress along the selected region such that the amount of cold working of less than about 2%. In another preferred embodiment of the invention, the second operation is performed as an independent secondary operation. In another preferred embodiment of the invention, the first and the second operations are performed together in a single pass. In another preferred embodiment of the invention, the first operation is performed while the selected region of the part is at a first temperature and the second operation is performed while the selected region of the part being burnished is at a second temperature. Another preferred embodiment of the invention, an apparatus for inducing compressive residual stress in the surface of a part comprises a first compression inducing means having a burnishing member and a second compression inducing means having a burnishing member, wherein the burnishing member of the first compression inducing means has a diameter that is greater than or less than the diameter of the burnishing member of the second compression inducing means. In another preferred embodiment of the invention, the apparatus for inducing compressive residual stress in the surface of a part comprises a plurality of burnishing members having consecutively small diameters. In another preferred embodiment of the invention, the first compression inducing means is fixed in a first positioning device and the second compression inducing means is fixed in a second positioning device. In another preferred embodiment of the invention, the first compression inducing means and the second compression inducing means are fixed in a single positioning device. In another preferred embodiment of the invention, the modulus of elasticity of the burnishing member of the first compression inducing means is different than the modulus of elasticity of the burnishing member of the second compression inducing means. Various objects and advantages of the invention will be apparent from the following description, the accompanying drawings, and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS To provide a more complete understanding of the present invention and further features and advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings, in which: FIG. 1 is a schematic representation of a preferred embodiment of the apparatus of the present invention for inducing a layer of compressive residual stress in the surface of a part in which the means for inducing compression are fixed in a single positioning device effective for linear motion; FIG. 2 is a schematic representation of the preferred embodiment of the apparatus of FIG. 1 in which the means for inducing compression are fixed in separate positioning devices; FIG. 3 is a schematic representation of another preferred embodiment of the apparatus of the present invention for inducing a layer of compressive residual stress in the surface of a part in which the means for inducing compression are fixed in a single positioning device effective for both linear and rotational movement; FIG. 4 is a schematic representation of the preferred embodiment of the apparatus of FIG. 3 in which the means for inducing compression are fixed in separate positioning devices; FIG. 5 is a schematic representation of the apparatus of FIGS. 1 through 4 showing the relationships of the various components; FIG. 6 is a flowchart illustrating a preferred embodiment of the method of the present invention for inducing a layer of compressive residual stress in the surface of a part; FIG. 7 is a graphical illustration of the subsurface residual stress distributions produced by the method of the present invention whereby a first operation was a burnishing operation performed using a 2.5 in. (6.35 cm) diameter ball and a second operation was a burnishing operation performed using a 0.25 in. (0.64 cm) diameter ball to achieve compression of about 0.3 in (0.8 cm) into the surface of the part; FIG. 8 is a graphical illustration of the subsurface residual stress distributions produced by the method of the present invention whereby the modulus of elasticity of the burnishing member used in the second operation is higher than the modulus of elasticity of the burnishing member used in the first operation; FIG. 9 is a graph illustrating that a greater depth of compression can be achieved with increase loading in spherical ball burnishing (using a 0.75 in (1.9 cm) ball) at an elevated temperature of 400° F. (204° C.) as compared to the same process at room temperature; and FIG. 10 is a graph illustrating that an increase in surface tensile stress can be obtained by cooling the surface of the part (plotted as a function of the temperature differential between the surface and the interior of the part). DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for performing the method of inducing compressive residual stress along a selected region of a part. In describing the preferred embodiments of the invention illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. It has been found that the effect of secondary burnishing or deep rolling either parallel or perpendicular to the original path of the burnishing apparatus using the same burnishing member diameter and compressive loads have shown to have no significant effect on the residual stress developed. In order to facilitate the introduction of greater compressive residual stresses in a part, deep rolling and other conventional burnishing techniques have been developed that utilize multiple passes of the burnishing member over the surface of the part, often with an increasing load, to induce compressive residual stresses within the surface. For parts where it is desirable to minimize cold working of the surface, low plasticity burnishing have been developed that performs the burnishing operation in a single pass and exhibits the same compressive residual stresses as observed in conventional multi-pass burnishing. It has now been unexpectedly found that if a smaller ball or roller diameter is used over the surface of a previously burnished part, that a much higher state of compressive stress can be generated on the upper surface of the part, eliminating the problem of low surface compression. This process can be performed in stages with a single apparatus or using a series of burnishing apparatus having different size burnishing members, such as balls or rollers, whereby the burnishing members pass over the surface consecutively during a single pass or in multiple passes over the part. Referring to FIGS. 1 through 4, there is illustrated an apparatus 100 for inducing a residual compressive stress in the surface S of a part 102. According to one embodiment of the present invention, the apparatus 100 for inducing compressive residual stress along the surface S of a selected region of a part includes a first compression inducing means 104 and a second compression inducing means 106. While various compression tools have been developed for inducing a layer of residual compressive stress in the surface of a part, preferably, the first compression inducing means 104 and the second compression inducing means 106 preferably comprise conventional burnishing members 108 and 110, respectively. Various types of burnishing tools have also been developed, preferably the compression inducing means 104, 106 are single-point burnishing members, such as described in U.S. Pat. No. 5,826,453 entitled “Burnishing Method and Apparatus for Providing a Layer of Compressive Residual Stress in the Surface of a Workpiece,” which is assigned to an assignee of the present invention and is incorporated herein by reference. As illustrated, in a preferred embodiment of the invention, the compression inducing means 104 and 106 each include a burnishing ball 112, the forward most tip of which is caused to pass over the surface S of the part 102 in a rolling motion to induce deep compression. As schematically illustrated in FIGS. 1 and 3, the compression inducing means 104 and 106 are preferably mounted to a conventional single positioning device 114, such as a robotic arm or milling machine (not shown). As schematically illustrated in FIGS. 2 and 4, the compression inducing means 104 and 106 are preferably mounted to conventional separate positioning devices 114. Further, the burnishing members 108 and 110 may be mounted to a positioning device(s) 114 effective for linear motion, as shown in FIGS. 1 and 2, or to a positioning device(s) 114 effective for both linear and rotational motion, as shown in FIGS. 3 and 4. The direction of motion and speed of the apparatus 100 and the first and second inducing means 104 and 106 will depend upon the material forming the part 102 and the final application of the part, as well as the desired penetration of the residual compressive stress induced therein. The force applied by the compression inducing means 104 and 106 to the surface S of the part 102 will also depend on the desired penetration of residual compressive strength, material composition, material properties, and dimensions of the part 102, and the application of the final part. The apparatus 100 of the present invention can be manually or automatically operated. Referring to FIG. 1 and as schematically illustrated in FIG. 5, the apparatus 100 can include a controller 116 for automatically controlling the positioning device 114 and, thus, the direction of motion and speed of the compression inducing means 104 and 106. The controller 116 also can be used to control the force applied by the compression inducing means 104 and 106 to the surface S of the part 102. The controller 116 can include a microprocessor, such as a computer operating under computer software control. In one embodiment, the positioning device 114 includes belt and/or gear drive assemblies (not shown) powered by servomotors (not shown), as is known in the art. The controller 116 can be in operable communication with the servomotors of the positioning device 114 through suitable wiring (not shown). One or more sensors 118, including, but not limited to, linear variable differential transformers or laser, capacitive, inductive, or ultrasonic displacement sensors, which are in electrical communication with the controller 116 through suitable wiring, can be used to measure the spacing of the compression inducing means 104 and 106 above the surface S of the part 102, and, thus, the motion of the compression inducing means 104 and 106. Similarly, shaft encoders in servo systems, stepper motor drives, linear variable differential transformers, or resistive or optical positioning sensors can be used to determine the position of each compression inducing means 104 and 106 along the surface S of the part 102. One or more pressure sensors 120 including, but not limited to, load cells incorporating resistive, piezoelectric, or capacitive elements, which are in electrical communication with the controller 116 through suitable wiring, can be used to measure the amount of force applied by each of the compression inducing means 104 and 106 to the surface S of the part 102. For example, pressure transducers can be used to monitor the hydraulic pressure applied by a piston to determine the normal force on the compression inducing means 104 and 106. The measurements obtained by the motion and pressure sensors are communicated to the controller 116. The controller 116 compares the measurements to preprogrammed parameters and, if necessary, instructs the servomotors (not shown) of the positioning device 114 to make corrections or adjustments to the direction of motion, speed of motion, and/or force being applied by the compression inducing means 104 and 106. When inducing compressive residual stress along a selected region on the surface S of a part, the part 102 is preferably secured to a work table (not shown) by means of a clamp or similar device (not shown). The apparatus 100 is positioned relative to the part 102 such that the compression inducing means 104 and 106 are positioned adjacent to the surface S of the part 102. The first compression inducing means 104 is engaged and moved along the surface of a part 102 to induce a first layer of compression within the surface S. According to another embodiment (not shown), the first compression inducing means 104 is fixed and the part 102 is moved relative to the compression inducing means 104. Thereafter, the second compression inducing means 106 is engaged and moved along the surface S of the part 102 to induce residual compressive stress along the upper surface of the part 102. According to another embodiment (not shown), the second compression inducing means 104 is fixed and the part 102 is moved relative to the second compression inducing means 104. It should now be apparent that as shown in FIGS. 1 and 3, the first compression inducing means 104 and the second compression inducing means 106 can be fixed in a single positioning device 114 or can be fixed in separate positioning devices 114 as shown in FIGS. 2 and 4. As discussed above, the first and the second compression inducing means 104 and 106 operate by forcing the burnishing member 110 against the surface S of the part 102 to produce the zones of deformation and to induce both residual compressive stresses deep within the surface as well as along the upper surface of part 102. As previously described, in a preferred embodiment, the first compression inducing means 104 and the second compression inducing means 106 are attached to a shared positioning device 114 (FIGS. 1 and 3). As illustrated, the orientation and positioning of the first and the second compression inducing means 104, 106 are such that the second compression means 106 follows the same path of the first compression inducing means 104 thereby imparting additional compressive residual stresses within the surface S of the part 102. In another preferred embodiment, the first compression inducing means 104 and the second compression inducing means 106 are attached to separate positioning devices 114 (FIGS. 2 and 4). In this way, the second compression inducing means 106 may follow the same path of the first compression inducing means 104 or may follow a different path and may therefore impart a more complex pattern of residual stresses within the surface S of the part 102. According to another embodiment of the present invention, conventional X-ray diffraction techniques are used to analyze the surface S of the part 102 to determine a selected region, the desired compressive stress pattern, penetration depth, as well as the amount of cold working and surface hardening necessary to optimize the material properties of the part 102. The burnishing member 112 of each compression inducing means 104 and 106 can then be passed in a predetermined pattern with a constant or varying pressure, manually or using the controller 116, across the surface S of the part 102 to induce the desired pattern of residual compressive stresses within the surface S. Referring to FIG. 6, there is illustrated the method of inducing a layer of compression along the surface of a part, according to one embodiment of the present invention. The method includes the steps of selecting at least one region of the surface of a part for inducing a deep layer of compressive residual stress therein, step 202, and performing a first operation to induce a selected pattern of residual compressive stress within the region of the surface of the part, step 204. The method further includes selecting the same region and/or another region(s) for inducing a more shallow layer of compressive stresses, step 206, and performing a second operation to induce a second more shallow layer of compressive surface stresses along the selected region(s), step 208. In a preferred embodiment of the invention, the method includes controlling the amount of cold working and surface hardening in the portion of the surface of the part. For example, in one embodiment, the desirable amount of cold working may be less than about five percent (5%) or less than about two percent (2%). In another embodiment, the method of inducing the layer of compressive residual stress is by burnishing. In another embodiment, the first and second operations are performed such that the means for inducing compression across the surface of a part are moved in a predetermined pattern and pressure to induce zones of residual compressive stress that do not substantially overlap. In another embodiment, the method includes performing X-ray diffraction to determine the optimum compressive stress pattern to be induced within the surface of the part, step 210. In another embodiment, the first and the second operations are performed such that the direction of motion and/or the speed of motion of the means of inducing compression across the surface of the part are controlled. In yet another embodiment, the method includes adjusting the force being applied by the means of inducing compression against the surface of the part, step 212. The method of burnishing applied in a single-pass or in multiple passes can be effective for producing compressive residual stresses following tensile deformation of the part along the upper surface of the part and to a certain depth within the surface of the part and produces deep compression with minimal cold working. It has been found that single-point burnishing can be used to produce a part with less cold work and surface hardening than a part subjected to conventional burnishing operations. It has also been found that the layer of residual compressive stress developed, according to the present invention, penetrates to a greater depth than that developed by conventional burnishing. The amount of cold working and surface hardening also can be varied as part of the process to optimize the material properties of the part. The optimal amount of cold working and surface hardening will depend on the particular material of the part and the environment which the part will be subjected to during its life. It has been found, however, that by cold working the surface of the part by less than about five percent (5%) and, more preferably, by less than about two percent (2%), results in a part having longer retention of residual compressive stress at elevated temperature, less rapid relaxation under cyclic loading, and less alteration of the residual stress field during tensile or compressive overload than parts formed using conventional cold working and surface hardening processes. Referring to FIG. 7, a graphical representation illustrating the subsurface residual stress distributions produced by the method of the present invention is shown whereby the first operation for inducing compressive residual stress in the surface of the part was performed using a 2.5 in. (6.35 cm) diameter ball burnishing member and the second operation was performed using a 0.25 in. (0.64 cm) diameter ball burnishing member to achieve compression of about 0.31 in. (0.8 cm) into the surface of the part. The upper graph shows the residual stress distributions as functions of depth and shows the increased compression achieved to a depth of less than about one millimeter due to the use of the second pass burnishing operation. Referring to FIG. 8, a graphical representation illustrating the subsurface residual stress distributions produced by conventional burnishing and by the method of the present invention is shown whereby conventional burnishing was performed for inducing compressive residual stress in the surface of the part using a 0.25 in. (0.635 cm) diameter ball burnishing member in a single pass and the method of the present application by performing a first operation using a 0.25 in. (0.635 cm) diameter burnishing member and a second operation using a 0.25 in. (0.64 cm) diameter ball burnishing member whereby the modulus of elasticity of the burnishing member used in the second operation is greater than the modulus of elasticity of the burnishing member used in the first operation. As can be seen, the residual stress distributions as a function of depth shows the increased compression achieved to a depth of less than about one millimeter due to the use of the second pass burnishing operation. It has also been found that by inducing a layer of compressive residual stress in the surface of a part, such as by burnishing, along regions having elevated temperature produces residual stresses that are more stable when subjected to elevated temperature. Such stability is believed to be attributed to strain aging which occurs during the warm deformation process that leads to more diffuse dislocation structures and pinning of dislocations by solute atoms and/or precipitates. It has also been found that by performing the compression operation with the surface of the part heated to an elevated temperature, rather than at room temperature, produces a deeper compressive residual stress layer. Because of the reduction of the part yield strength, plastic deformation extends to a greater depth thereby producing deeper compression, as well as deeper penetration of the burnishing tool, thereby producing more lateral flow of surface material and higher surface compression. Accordingly, the method of inducing a compressive residual stress along the surface of a part may include the step of heating and/or cooling the surface prior to performing the first operation and/or prior to performing the second operation, step 214. As illustrated in FIG. 8, the depth of compression, calculated using conventional finite element methods and published yield strengths, achieved by burnishing a material, such as 7075-T6 aluminum, at a heated temperature, such as 400° F. (204° C.), is over twice the depth of compression achieved by burnishing at room temperature. The depth of compression achieved increases with the increasing burnishing load. It should now be apparent to those skilled in the art that by performing a first operation at a first temperature and then a second operation at a second temperature can induce multiple layers of residual compressive stress or that various patterns of compressive residual stress can be induced along the surface of a part. Further, by performing the method of the present application using various combinations of burnishing members having different diameters and/or different modulus of elasticity, burnishing patterns, and surface temperatures, numerous compressive residual stress patterns and layers can be induced within the surface of a part. It should also now be apparent to those skilled in the art that parts can now be manufactured or treated having optimum compressive residual stress patterns that will improve fatigue life and reduce susceptibility to corrosion-fatigue and stress corrosion cracking. Further, by performing X-ray diffraction the optimum compressive stress pattern obtainable can be determined. Accordingly, the method and the apparatus of the present invention is a relatively inexpensive and effective means of inducing a desired layer of compressive residual stress in the surface of a part for providing the optimum fatigue life for reducing susceptibility to corrosion-fatigue and stress corrosion cracking. | <SOH> BACKGROUND OF THE INVENTION <EOH>This invention relates to a method and an apparatus for performing the method of inducing compressive residual stress along the surface of a part and, more particularly, to a method and an apparatus for performing the method of burnishing or deep rolling a surface of a part whereby the magnitude and penetration of compressive residual stress achieved is greater than that achieved by conventional burnishing. Surface residual stresses are known to have a major affect upon the fatigue and stress corrosion performance of components or parts in service. Tensile residual stresses that can be developed during manufacturing processes, such as grinding, turning, or welding are well known to reduce both fatigue life and increase sensitivity to corrosion-fatigue and stress corrosion cracking in a wide variety of materials. It is also known that compressive residual stresses induced in the surface of a part can increase its fatigue life and reduce its susceptibility to corrosion-fatigue and stress corrosion cracking. However, the benefit of inducing a layer of surface compression in reducing susceptibility to stress corrosion, cracking, fatigue, and corrosion-fatigue is lost if the layer of compression relaxes with time in service. Many components and parts of practical interest are subject to high tensile cyclic loads or high mean loads that often lead to fatigue, corrosion fatigue, stress corrosion, or a combination of such failure modes. Therefore, it would be desirable to be able to introduce a layer of compressive residual stress along the surface of a part that will not relax significantly over time. A method that has been developed and is widely used in industry to improve surface finish as well as fatigue life and corrosion resistance of a part by inducing a layer of compressive residual stress along its surface of the part is known as burnishing. During the burnishing process, the surface of a part is deformed by a rotary or sliding burnishing member that is pressed against the part in order to compress the microscopic peaks formed along the surface of the part into adjacent hollows. Burnishing thereby operates to develop compressive stresses by yielding the surface of the part in tension so that it returns to a state of compression following deformation. Burnishing tools comprising various wheel or roller burnishing member configurations have been developed for cold working a part and to induce a state of compressive stress and improved surface finish to the part. In addition, “deep rolling” and “low plasticity burnishing” processes have also been developed for producing deep layers of compressive stress that approach the yield strength of the material and which extend to over a millimeter into the surface. However, the deformation mechanism for producing such compressive stresses is based on hertzian loading and will generally produce maximum compression below the surface of the part. In many high strength or work hardening materials, the stresses produced along the upper surface by these burnishing methods can be far less than the subsurface maximum, often being close to or having zero compression at the upper surface. Processes have therefore been developed to increase the stress levels at the upper surface of a part. Such processes include removing a thin layer of material from the surface of the part, such as by etching, electropolishing, or some other non-tensile stress forming process; or a post treatment, such as shot peening, grit blasting, or similar compression producing treatments, to render the surface more highly compressive. Unfortunately, both approaches require a secondary surface treatment unrelated to the original burnishing process thereby adding time, cost, and the potential for damage and the loss of the part during manufacture. With respect to shot peening operations, secondary peening operations have been used to improve surface compression. For example, to increase the state of surface compression in a part, secondary peening operations have been performed using small glass or ceramic shot following conventional steel shot peening with larger shot. Shot peening while being relatively inexpensive and preferred for many applications, is often unable to obtain the necessary coverage of the part without overlaping areas of impingement. Such overlapping often results in relatively large amount of cold working which may leave the surface compressive layer susceptible to stress relaxation. Further, shot peening is often unacceptable for use in manufacturing parts requiring a superior finish, localized or relatively complex compressive stress zones or patterns, or requiring a greater depth of compressive stress penetration. Consequently, it would be desirable to have a relatively inexpensive and time efficient method and apparatus for implementing the method of improving the physical properties of a part by increasing the magnitude and penetration of compressive stress on the surface that would not significantly relax over time. It would also be desirable to have a method and an apparatus that would be effective for use with complex shaped surfaces and without detracting from the finish of the surface, and which could be performed relatively inexpensively and in a single pass. | <SOH> SUMMARY OF THE INVENTION <EOH>The novel method of the present invention for inducing compressive stress on the surface of a part comprises the steps of selecting at least one region along the surface of the part for inducing compressive surface stresses; performing a first operation to induce compressive surface stresses along the selected region of the part; and performing a second operation to induce a second layer of compressive surface stresses along the selected region of the part. In another preferred embodiment of the invention the compressive surface stresses are induced into the selected region of the part by exerting compressive forces against the surface such that during the first operation the compressive force is greater than the compressive force exerted during the second operation. In another preferred embodiment of the invention the first operation and the second operation of inducing compressive residual stresses along the surface of the part are burnishing operations. In another preferred embodiment of the invention the burnishing operations are performed using a compression inducing means having a first burnishing member and a second burnishing member whereby the first burnishing member has a different modulus of elasticity than the second burnishing member. In another preferred embodiment of the invention, the diameter of the first burnishing member is smaller than the diameter of the second burnishing member. In another preferred embodiment of the invention the diameter of the first burnishing member is larger than the diameter of the second burnishing member. In another preferred embodiment of the invention, the method induces at least one layer of compressive residual stress along the selected region such that the amount of cold working of less than about 5%. In another preferred embodiment of the invention, the method induces at least one layer of compressive residual stress along the selected region such that the amount of cold working of less than about 2%. In another preferred embodiment of the invention, the second operation is performed as an independent secondary operation. In another preferred embodiment of the invention, the first and the second operations are performed together in a single pass. In another preferred embodiment of the invention, the first operation is performed while the selected region of the part is at a first temperature and the second operation is performed while the selected region of the part being burnished is at a second temperature. Another preferred embodiment of the invention, an apparatus for inducing compressive residual stress in the surface of a part comprises a first compression inducing means having a burnishing member and a second compression inducing means having a burnishing member, wherein the burnishing member of the first compression inducing means has a diameter that is greater than or less than the diameter of the burnishing member of the second compression inducing means. In another preferred embodiment of the invention, the apparatus for inducing compressive residual stress in the surface of a part comprises a plurality of burnishing members having consecutively small diameters. In another preferred embodiment of the invention, the first compression inducing means is fixed in a first positioning device and the second compression inducing means is fixed in a second positioning device. In another preferred embodiment of the invention, the first compression inducing means and the second compression inducing means are fixed in a single positioning device. In another preferred embodiment of the invention, the modulus of elasticity of the burnishing member of the first compression inducing means is different than the modulus of elasticity of the burnishing member of the second compression inducing means. Various objects and advantages of the invention will be apparent from the following description, the accompanying drawings, and the appended claims. | 20040117 | 20070313 | 20050721 | 72503.0 | 0 | HONG, JOHN C | METHOD AND APPARATUS FOR IMPROVING THE MAGNITUDE OF COMPRESSIVE STRESS DEVELOPED IN THE SURFACE OF A PART | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,759,988 | ACCEPTED | Numerical value conversion using a saturation limited arithmetic logic unit supporting variable resolution operands | A device for performing numerical value conversion of a digital input value in a first unit to a second, natural unit where the digital input value is a digitized value of a first measurement parameter includes a look-up table storing an array of coefficients for performing the numerical value conversion for multiple measurement parameters. The look-up table is indexed using a first parameter indicative of the first measurement parameter to provide a selected coefficient. The device further includes an arithmetic logic unit (ALU) receiving the digital input value and the selected coefficient and performing the numerical value conversion based on a first equation and the selected coefficient to compute a digital output value. The device also includes a saturation-limit circuit coupled to receive the digital output value from the arithmetic logic unit and provide a predetermined output value when the digital output value exceeds a predetermined maximum value. | 1. A device for performing numerical value conversion of a digital input value in a first unit to a second unit being a natural unit, the first unit being related to the second unit by a first equation, the digital input value being a digitized value of a first measurement parameter among a plurality of measurement parameters, the device comprising: a look-up table storing a plurality of coefficients for performing the numerical value conversion from the first unit to the second unit for each of the plurality of measurement parameters, the look-up table being indexed using a first parameter to provide a selected coefficient, the first parameter being indicative of the first measurement parameter; an arithmetic logic unit receiving the digital input value in the first unit and the selected coefficient from the look-up table, the arithmetic logic unit performing the numerical value conversion based on the first equation and using the selected coefficient to compute a digital output value in the second unit; and a saturation-limit circuit coupled to receive the digital output value in the second unit from the arithmetic logic unit and provide a predetermined final output value when the digital output value exceeds a predetermined minimum or maximum value. 2. The device of claim 1, wherein the saturation-limit circuit provides a first predetermined final output value when the digital output value exceeds a predetermined maximum value and provides a second predetermined final output value when the digital output value is below a predetermined minimum value. 3. The device of claim 2, wherein the digital output value comprises values between a maximum output value and a minimum output value, the first predetermined final output value being the maximum output value and the second predetermined final output value being the minimum output value. 4. The device of claim 3, wherein the second predetermined final output value is zero. 5. The device of claim 1, wherein the arithmetic logic unit comprises a fixed-function arithmetic logic unit capable of performing only multiplication and addition operations. 6. The device of claim 1, wherein the first unit comprises an arbitrary unit and the second unit comprises a natural unit of physical measurement. 7. The device of claim 6, wherein the numerical value conversion from the arbitrary unit to the natural unit has a linear relationship described by the equation DN=mDA+C, where DA is the digital input value, DN is the digital output value, m is a slope coefficient and c is an offset coefficient, and the plurality of coefficients comprises a plurality of coefficient pairs for each of the plurality of measurement parameters, each coefficient pair comprising a slope coefficient and an offset coefficient. 8. The device of claim 6, wherein the numerical value conversion for the selected measurement parameter from the arbitrary unit to the natural unit has a non-linear relationship and the plurality of coefficients comprises a first set of coefficients for the selected measurement parameter, the first set of coefficients implementing the numerical value conversion in a piecewise-linear fashion approximating the non-linear relationship. 9. The device of claim 8, wherein the first set of coefficients comprises coefficients for a plurality of linear segments for performing the piecewise-linear numerical value conversion, each linear segment being described by the equation. DN=mDA+c, where DA is the digital input value, DN is the digital output value, m is a slope coefficient and c is an offset coefficient for the respective linear segment, and the first set of coefficients comprises a plurality of coefficient pairs, each coefficient pair comprising a slope coefficient and an offset coefficient for the respective linear segment. 10. The device of claim 9, wherein the digital input value comprises an N-bit digital value and the first parameter comprises the most significant k bits of the digital input value where k is less than N. 11. The device of claim 1, wherein the digital input value comprises a first digital input value of a first bit length and a second digital input value of a second bit length different than the first bit length. 12. A method for performing numerical value conversion of a digital input value in a first unit to a second unit being a natural unit, the first unit being related to the second unit by a first equation, the digital input value being a digitized value of a first measurement parameter among a plurality of measurement parameters, the method comprising: storing a plurality of coefficients in a look-up table for performing the numerical value conversion from the first unit to the second unit, each of the plurality of measurement parameters being associated with at least one of the plurality of coefficients; indexing the look-up table using a first parameter being indicative of the first measurement parameter to provide a selected coefficient; providing the digital input value and the selected coefficient to an arithmetic logic unit; performing a numerical value conversion at the arithmetic logic unit based on the first equation and using the selected coefficient to compute a digital output value in the second unit from the digital input value in the first unit; determining if the digital output value exceeds a predetermined maximum value; providing a first predetermined value as the final output value when the digital output value exceeds the predetermined maximum value; and providing the digital output value as the final output value when the digital output value does not exceed the predetermined maximum value. 13. The method of claim 12, further comprising: determining if the digital output value is less than a predetermined minimum value; providing a second predetermined value as the final output value when the digital output value is less than the predetermined minimum value; and providing the digital output value as the final output value when the digital output value exceeds the predetermined minimum value. 14. The method of claim 12, wherein the digital output value comprises values between a maximum output value and a minimum output value, the first predetermined value being the maximum output value and the second predetermined value being the minimum output value. 15. The method of claim 12, wherein providing the digital input value and the selected coefficient to an arithmetic logic unit comprises: providing the digital input value and the selected coefficient to a fixed-function arithmetic logic unit capable of performing only multiplication and addition operations. 16. The method of claim 12, wherein the digital input value comprises a first digital input value of a first bit length and a second digital input value of a second bit length different than the first bit length. 17. The method of claim 12, wherein storing a plurality of coefficients in a look-up table for performing the numerical value conversion from the first unit to the second unit comprises: storing a plurality of coefficients in the look-up table wherein the numerical value conversion from the arbitrary unit to the natural unit has a linear relationship described by the equation DN=mDA+c, where DA is the digital input value, DN is the digital output value, m is a slope coefficient and c is an offset coefficient, and the plurality of coefficients comprises a plurality of coefficient pairs for each of the plurality of measurement parameters, each coefficient pair comprising a slope coefficient and an offset coefficient. 18. The method of claim 12, wherein storing a plurality of coefficients in a look-up table for performing the numerical value conversion from the first unit to the second unit comprises: storing a plurality of coefficients in the look-up table wherein the numerical value conversion from the arbitrary unit to the natural unit has a non-linear relationship and the plurality of coefficients comprises a first set of coefficients for the selected measurement parameter, the first set of coefficients implementing the numerical value conversion in a piecewise-linear fashion approximating the non-linear relationship. 19. The method of claim 18, wherein the first set of coefficients comprises coefficients for a plurality of linear segments for performing the piecewise-linear numerical value conversion, each linear segment being described by the equation DN=mDA+c, where DA is the digital input value, DN is the digital output value, m is a slope coefficient and c is an offset coefficient for the respective linear segment, and the first set of coefficients comprises a plurality of coefficient pairs, each coefficient pair comprising a slope coefficient and an offset coefficient for the respective linear segment. 20. The method of claim 12, wherein the digital input value comprises an N-bit digital value and the first parameter comprises the most significant k bits of the digital input value where k is less than N. | CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/530,022, filed on Dec. 15, 2003, having the same title and inventorship hereof, which application is incorporated herein by reference in its entirety. This application is related to concurrently filed and commonly assigned U.S. patent application Ser. No. ______ (Attorney Docket No. MIC-M096), entitled “Numerical Value Conversion Using A Look-Up Table For Coefficient Storage,” of the same inventors hereof. FIELD OF THE INVENTION The invention relates to a device for performing numerical value conversion and, in particular, to a device for performing numerical value conversion including an arithmetic logic unit that is saturation limited and supports variable resolution operands. DESCRIPTION OF THE RELATED ART The present invention concerns devices that are used to convert numerical values from one unit system to another unit system. For example, an analog-to-digital convert (ADC) is often used to digitize an analog data source into digital values. The digital values, sometimes referred to as “digital bits,” often have to be expressed as real-word parameters, such as voltage, current, and temperature. In operation, the ADC digitizes the analog data source (temperature, voltage or current) into digital values in arbitrary units. Then, the ADC uses an arithmetic logic unit (ALU) to convert the digital values in an arbitrary unit into an appropriate real-world unit (e.g., degree Celsius, volts and ampere). For example, the ADC may digitize an input voltage value and provide values in whole numbers of millivolts as the digital output. The numerical value conversion process uses one or more coefficients for transforming the digital values in arbitrary units into the desired real-world unit. Typically, the coefficients are stored in a memory or registers and are retrieved by the ALU to perform the conversion. Thus, in conventional systems, the coefficients are treated as constants to be applied for the conversion of all digitized values. However, in some applications, the values of the coefficients to be used may vary depending on certain parameters, such as the operating conditions of the device generating the analog data source or the device generating the digitized values. It is therefore desirable to provide a means to implement a numerical value conversion process that supports the use of multiple coefficients selected based on one or more parameters. In most applications, an analog-to-digital converter is used to digitize a single analog data source. However, in some applications, it is desirable to use a single analog-to-digital converter to digitize multiple analog data sources. In that case, there is a requirement to convert digital values from the ADC into various physical units, each conversion requiring separate set of coefficients. It is desirable to provide a means to implement a numerical value conversion process that supports the use of multiple coefficients for realizing numerical value conversion into multiple units. As described above, the conversion process in an ADC uses an ALU to carry out the numerical value transformation. An ALU typically includes built-in multiplication and addition functions and is often designed to operate with digital input values of a pre-determined bit length. However, when the ADC is used to digitize multiple analog input data sources, the digitized data values may have different bit lengths for the different analog data source. Thus, when a single ADC is used for digitizing multiple analog data source and the resultant digitized data are of variable resolution, separate ALUs are usually needed for converting the ADC results having variable bit lengths. In some applications, limitations on the size of the integrated circuit make it undesirable to provide multiple ALUs in order to support ADC functions providing variable bit length ADC results. SUMMARY OF THE INVENTION According to one embodiment of the present invention, a device for performing numerical value conversion of a digital input value in a first unit to a second unit being a natural unit where the first unit is related to the second unit by a first equation is disclosed. The digital input value is a digitized value of a first measurement parameter among multiple measurement parameters. The device includes a look-up table storing an array of coefficients for performing the numerical value conversion from the first unit to the second unit for each of the multiple measurement parameters. The look-up table is indexed using a first parameter to provide a selected coefficient where the first parameter is indicative of the first measurement parameter. The device further includes an arithmetic logic unit receiving the digital input value in the first unit and the selected coefficient from the look-up table. The arithmetic logic unit performs the numerical value conversion based on the first equation and using the selected coefficient to compute a digital output value in the second unit. Finally, the device includes a saturation-limit circuit coupled to receive the digital output value in the second unit from the arithmetic logic unit and provide a predetermined final output value when the digital output value exceeds a predetermined minimum or maximum value. In another embodiment, the arithmetic logic unit is a fixed-function ALU capable of multiplication and addition operations only. In yet another embodiment, the arithmetic logic unit is disposed to support digital input values having variable bit length. According to another aspect of the present invention, a method for performing numerical value conversion of a digital input value in a first unit to a second unit being a natural unit where the first unit is related to the second unit by a first equation is disclosed. The digital input value is a digitized value of a first measurement parameter among multiple measurement parameters. The method includes storing an array of coefficients in a look-up table for performing the numerical value conversion from the first unit to the second unit where each of the multiple measurement parameters is associated with at least one coefficient in the array of coefficients, indexing the look-up table using a first parameter being indicative of the first measurement parameter to provide a selected coefficient, providing the digital input value and the selected coefficient to an arithmetic logic unit, and performing a numerical value conversion at the arithmetic logic unit based on the first equation and using the selected coefficient to compute a digital output value in the second unit from the digital input value in the first unit. The method further includes determining if the digital output value exceeds a predetermined maximum value, providing a first predetermined value as the final output value when the digital output value exceeds the predetermined maximum value, and providing the digital output value as the final output value when the digital output value does not exceed the predetermined maximum value. In another embodiment, the method further includes determining if the digital output value is less than a predetermined minimum value, providing a second predetermined value as the final output value when the digital output value is less than the predetermined minimum value, and providing the digital output value as the final output value when the digital output value exceeds the predetermined minimum value. The present invention is better understood upon consideration of the detailed description below and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a device for performing numerical value conversion using a look-up table for coefficient storage according to one embodiment of the present invention. FIG. 2 illustrates a look-up table that uses temperature as an index into a memory-based table of coefficient pairs. FIG. 3 is a graph illustrating the effect of using coefficients that are dependent on temperature for converting ADC results. FIG. 4 illustrates a look-up table that implements numerical value conversion using a piecewise-linear approach. FIG. 5 is a graph illustrating the effect of using the look-up table of FIG. 4 to implement a piecewise-linear approach for approximating a non-linear conversion relationship. FIG. 6 is a schematic diagram of a device for performing numerical value conversion using a look-up table for coefficient storage according to an alternate embodiment of the present invention. FIG. 7 is a schematic diagram of a device for performing numerical value conversion using a look-up table for coefficient storage and a saturation limited ALU according to one embodiment of the present invention. FIG. 8 is a schematic unit of an ALU implementing variable bit-length operands according to one embodiment of the present invention. FIG. 9 is a schematic diagram of one embodiment of a clamp circuit which can be used in the numerical value conversion device of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In accordance with the principles of the present invention, a numerical value conversion device uses a look-up table for storing coefficients for performing conversion of a digital value in one unit to a digital value in another unit. The look-up table can be indexed by one or more parameters to provide the desired coefficients for use in the conversion computation. Furthermore, the look-up table can store coefficients for providing linear or non-linear conversions. In one embodiment, the look-up table is indexed by an operating parameter, such as temperature, and the look-up table stores coefficients for providing a linear conversion incorporating temperature compensation. In another embodiment, the look-up table is indexed by a portion of the most significant bits of the digital input value and the look-up table stores coefficients for providing numerical value conversion in a piecewise-linear fashion. The piecewise-linear conversion is used to approximate non-linear conversions, such as a logarithm conversion from a voltage value into Decibels. By using a look-up table for coefficient storage, complex numerical value conversion can be performed with simple and minimum circuitry. The numerical value conversion method and device of the present invention can be applied to systems where device size and operation speed is critical. According to another aspect of the present invention, a numerical value conversion device is coupled to perform numerical value conversion of digital input values derived from multiple data sources (or input channels) using coefficients stored in a look-up table. The look-up table is indexed by a selection parameter to provide the appropriate coefficients for the digital input value being processed. The numerical value conversion device includes an ALU that supports digital input values having variable resolution and provides digital output values also in variable resolution. Finally, the numerical value conversion device is saturation-limited so that a reasonable output value is always provided regardless of possible errors in the digital input values. Numerical Value Conversion Using a Look-Up Table The numerical value conversion method and device of the present invention can be applied to perform conversion of digital input values from any data source. Basically, the numerical value conversion method of the present invention can be used to convert digital input values expressed in a first unit system to digital output values expressed in a second unit system. The relationship between the first unit system and the second unit system can be linear or non-linear. However, applying the method and device of the present invention in an analog-to-digital converter provides particular advantages where conversion of the ADC results into natural units is often required. As mentioned above, ADC typically generates digital values in an arbitrary unit and the digital values have to be converted into a real-world unit or a natural unit to be useful. In the present description, real-world units or natural units refer to units of physical measurement such as degree Centigrade, volts, ampere, Decibels and watts. In the following description, the numerical value conversion method and device are described as being implemented in an analog-to-digital converter coupled to digitize one or more analog data source. However, the implementation of the method and device of the present invention in an analog-to-digital converter is illustrative only. In other embodiments, the numerical value conversion method or device can be applied for performing numerical value conversion of other digital data source whether provided by an ADC or not. In the present description, the digital output values of an analog-to-digital converter is referred to as the ADC results or the digital bits and are the digital input values into the numerical value conversion device of the present invention. Analog to digital converters generally produce results that are not comprehensible as natural units. For example, an ADC measuring voltage to a resolution of eight bits might have a full-scale value of 11111111 (255 decimal, FF hexadecimal). The full-scale value may correspond to a full-scale voltage of 1.25 volts. When the ADC digitizes a 1 volt signal, the digital result is an arbitrary binary number, such as 11001100 (204 decimal, CC hex). There is often a need to provide the ADC results in a more user-friendly format. For example, it is often desirable to display the ADC result for the 1-Volt signal as 1000 millivolts (1111101000 binary). To convert digital values expressed in an arbitrary unit to a natural unit, a slope/offset conversion equation is often used. The relationship between the digital value and the natural unit value is expressed as: DN=mDA+c, Eq. (1) where DN is the desired digital output value in a natural unit, DA is the digital input value to be converted in an arbitrary unit, m is a slope coefficient, and c is an offset coefficient. In the case of a digitized voltage value, the relationship between the digitized voltage value in an arbitrary ADC unit and the voltage value in a natural unit can be expressed as: Vn=mVADC+c, Eq. (2) where Vn is the desired digital output voltage value in a natural unit (e.g. volts or millivolts), VADC is the digitized voltage value to be converted in an arbitrary unit, m is a slope coefficient, and c is an offset coefficient. When applied to the example given above where an 8-bit full-scale range represents 1.25 volts, a slope coefficient m of 4.90196 and an offset coefficient c of 0 can be used to perform the numerical value conversion between the arbitrary ADC unit and the natural unit. Thus, the conversion equation is given as: Vn=4.90196VADC. When VADC=204, then Vn=1000. By performing the numerical value conversion, the ADC result can be meaningfully expressed as a value in millivolts. The computation of the numerical value conversion is performed by an arithmetic logic unit (ALU), which has built-in multiplication and addition functions. In conventional systems, the coefficients m and c are often treated as constants, provided from registers or memory. However, in accordance with the present invention, a set of coefficients m and c are provided and stored in a look-up table such that the values of the coefficients used for the conversion can be selected based on other parameters. For example, the coefficients can be selected based on the operating conditions or parameters of the system providing the digital values. In this manner, a more accurate numerical value conversion can be realized. Alternately, more complex numerical value conversions can also be implemented with simplified circuitry. FIG. 1 is a schematic diagram of a device for performing numerical value conversion using a look-up table for coefficient storage according to one embodiment of the present invention. Referring to FIG. 1, the numerical value conversion device receives a source of digital input values from an ADC 12. The digital input values are provided to an ALU 16 on a bus 14. ALU 16 also receives slope and offset coefficients from a look-up table 20. Look-up table 20 is indexed by a system parameter, referred herein as “P1,” and provides a selected pair of slope and offset coefficients on bus 18 to ALU 16. ALU 16 performs the numerical conversion of the digital input values on bus 14 using the coefficients supplied on bus 18 based on Equation (1) above. A digital value in the desired natural unit is provided on an output port 22 of ALU 16. Look-up table 20 can be implemented as a memory unit, such as a random-access memory. In the present embodiment, look-up table 20 stores pairs of slope m and offset c coefficients. The pairs of coefficients are related to the system parameter P1. System parameter P1 can represent characteristics or operating conditions of the system in which the analog data source is generated or of the system in which the digital input values is generated, such as the ADC. For example, in one embodiment, the pairs of coefficients are a function of the operating temperature. By using a set of coefficients m and c that depends on the desired system parameter, the numerical value conversion process can be tailored specifically to provide the desired output values in a natural unit. Coefficients Indexed by Temperature In one embodiment of the present invention, the numerical value conversion device includes a look-up table storing coefficients that are indexed by temperature as the indexing parameter. FIG. 2 illustrates a look-up table 30 that uses temperature as an index into a memory-based table of coefficient pairs. In the embodiment shown in FIG. 2, each entry of the look-up table includes a pair of coefficients—the slope m and the offset c. Each entry is indexed by a 16° C. temperature range. Thus, a total temperature range from 0 to 127° C. is divided into eight entries in look-up table 30. In the present embodiment, the temperature used to index the look-up table is the operating temperature of the analog-to-digital converter providing the source of digital input values to ALU 16 (FIG. 1). That is, the temperature of ADC 12 is used as the indexing parameter. Because the behavior of the ADC may vary depending on the operating temperature, a numerical value conversion method using coefficients that are selected on the operating temperature can provide more accurate converted values. In other embodiments, the temperature used to index the look-up table can be a temperature value measured at any location of interest. For example, the system in which the numerical value conversion device is incorporated may include terminals for coupling to remote temperature sensors for providing the temperature values of interest. When a numerical value conversion is to be carried out, the operating temperature is used to index look-up table 30 to retrieve the corresponding pair of coefficients. For example, when the system temperature is 25° C., the second coefficient pair (Slope/Offset 1) will be retrieved from look-up table 30 entry 1 and delivered to the ALU. FIG. 3 is a graph illustrating the effect of using coefficients that are dependent on temperature for converting ADC digital values. Referring to FIG. 3, the conversion of the ADC results in arbitrary unit into converted values of a selected natural unit is linear for each given temperature range. By using a set of temperature-dependent coefficients, the numerical value conversion device enables the ADC system to temperature compensate the numerical value conversion. In the present illustration, the offset coefficients, c, are assumed to be zero. A zero offset value is useful when the system requires that a zero ADC result corresponds to a zero converted value at a particular temperature. The temperature compensation provided by using temperature-dependent coefficients stored in look-up table 30 is a useful feature in most real systems as system behaviors are often highly dependent on temperature. Referring to FIG. 3, due to the nature of a typical ADC, a given ADC result may correspond to different converted values depending on the operating temperature. Thus, by using a set of temperature-dependent coefficients, accurate conversion of ADC results into values in the desired natural unit is realized. FIG. 2 illustrates the use of a look-up table to store temperature-dependent coefficients for use in the numerical value conversion device and method of the present invention. In other embodiments, the look-up table can store coefficients that are dependent on other parameters, such as operating voltage or power. In general, look-up table 30 can be used to store coefficients as a function of system parameters that have a linear relationship between the digital input values and the converted values. Coefficients Indexed by ADC Result While the method described above with reference to FIGS. 1 and 2 can be used to facilitate numerical value conversion for system parameters that have a linear relationship between the digital input values and the converted values, in some applications, the relationship between the digital input values and the chosen set of natural units is non-linear. For example, an ADC might digitize a voltage signal, but a digital value in Decibels (dB) is desired. The relationship between voltage and Decibel is in a logarithmic scale, not linear. In this case, the non-linear relationship can be expressed as a polynomial with coefficients and exponents as follows: V1=m1V+m2V2+m3V3+m4V4+c, Eq. (3) where Vn is the desired output voltage value in Decibels, V is the digitized voltage value to be converted in an arbitrary unit, m1 to m4 are the polynomial coefficients and c is an offset coefficient. While it is possible to build an ALU to evaluate such a polynomial, the resulting ALU is usually very slow and large in size making such implementation undesirable. In applications where speed or device size is critical, direct calculation using an ALU is not practical. In accordance with an alternate embodiment of the present invention, a numerical value conversion device supports non-linear conversion by using coefficients that implement a piecewise-linear conversion. FIG. 4 illustrates a look-up table 40 that implements numerical value conversion using a piecewise-linear approach. Referring to FIG. 4, look-up table 40 includes entries for storing pairs of slope and offset coefficients. Look-up table 40 uses the top three bits (the most significant three bits) of the digital input values to be converted as the index to the memory-based table of coefficient pairs. Using the top three bits of the digital input values as an index effectively partitions the range of the digital input values into small regions where each region employs a linear conversion of the digital input value to the desired converted output value. Each entry of the look-up table thus includes coefficients associated with a region of the digital input values. In this manner, a piecewise-linear conversion is implemented to approximate the non-linear relationship between the digital input value and the converted value. In one embodiment, the numerical value conversion is used to operate on a parameter called “Received Power” which is a measurement of the amount of energy received by a photodiode at the end of an optical fiber. There is a non-linear relationship between the photodiode's output (measured as a voltage) and the desired output result, a value to be expressed in Decibels. The numerical value conversion device for converting a digitized voltage value into a value in Decibels unit operates as follows. First, a digital input value is provided to the numerical value conversion device. In the present embodiment, the digital input value is provided by an ADC digitizing the photodiode's output voltage into a digital input value having an arbitrary unit. Then, the most significant three bits of the digital input value are used to index look-up table 40 to select one of eight pairs of slope and offset coefficients. Returning to FIG. 4, the eight entries of the look-up table are indexed by three digital bits from 000 to 111. When an entry is selected using the three most significant bits of the digital input value, the slope and offset coefficients of the entry is retrieved and sent to the ALU for performing the conversion of the digital input value. The effect of the piecewise-linear conversion is shown in FIG. 5. The dotted-line curve represents the ideal logarithmic conversion from the ADC results (a digitized voltage value) to a converted value in dB. The solid-line curve represents the piecewise-linear approximation of the conversion using look-up table 40 of FIG. 4. The use of the most significant three bits of the ADC result partitions the range of digital input values into eight regions, each region being assigned its own pair of slope and offset coefficients. By careful selection of coefficients (slope and non-zero'offset), adjacent regions of the linear curve can join accurately so that no discontinuities are observed in the converted result. In the above description, the digital input value has 8 bits and the most significant 3 bits are used as the indexing parameter. Using the most significant 3 bits is illustrative only. In other embodiments, the digital input value has N bits and the most significant k bits are used as indexing parameter where k is less than N. The number of bits used as indexing parameter determines the size of each piecewise-linear partition and the total number of partitions used to approximate the full range of digital input values. FIG. 6 is a schematic diagram of a device for performing numerical value conversion using a look-up table for coefficient storage according to an alternate embodiment of the present invention. Referring to FIG. 6, an ADC 62 provides a source of digital input values on a bus 64 to an ALU 66 to be converted to a digital output value having a desired natural unit. The coefficients for performing the conversion are stored in a look-up table 70. In the present embodiment, look-up table 70 is designed to be indexed by multiple parameters. Specifically, the look-up table is indexed by a temperature parameter and a Received Power parameter (top three bits). A multiplexor 74 is coupled to select one of the two indexing parameters based on a Select signal. By incorporating multiplexor 74 to select between two indexing parameters, the numerical value conversion device can be selectively operated for temperature compensation or for non-linear conversion. In operation, the Select signal is asserted to select either the temperature or the Received Power as the indexing parameter. When the multiplexor selects temperature as the indexing parameter, an operating temperature value is used to select a pair of slope and offset coefficients. The selected coefficients are provided to ALU 66 on a bus 68. A linear conversion from the digital input value to the converted output value results. In the manner, temperature compensation of the ADC results is realized. When the multiplexor selects Received Power as the indexing parameter, the most significant 3 bits of the Received Power value is used to select a pair of slope and offset coefficients where the full 8 bits of the digital input value indicative of the Received Power is provided to ALU 66. A piecewise-linear conversion from the digital input value to the converted output value thus results. The use of a look-up table for storing coefficients for numerical value conversion in accordance with the present invention provides numerous advantages not realized by prior art systems. First, the numerical value conversion method stores only the coefficients used in the conversion computation. Thus, only a small amount of memory is needed and the size of the look-up table is minimized for optimal integration. The numerical value conversion device of the present invention is distinguishable from prior art systems where a look-up table may be used to store a large amount of scalar values which scalar values are used for scaling a binary value to another binary value, both binary values in arbitrary units. Such prior art systems require large amount of memory to implement and often do not provide numerical value conversion of the digital input values into values of a desired natural unit. Second, the numerical value conversion device of the present invention enables linear or non-linear conversion to be performed. Furthermore, the look-up table for storing coefficients can be indexed by one or more parameters depending on the application. Finally, by using a look-up table for coefficient storage, complex numerical value conversion can be performed with simple and minimum circuitry. As a result, an optimized coefficient storage mechanism is realized for efficient numerical value conversion. Saturated Limited ALU Supporting Variable Bit-Length Operands In the numerical conversion device described above, an ADC provides a source of digital input values for the ALU to perform numerical value conversions. While in most applications the ADC is used to digitize a single source of analog data, in some applications, the ADC may be coupled to digitize analog data from multiple sources. For example, in an optical transceiver, a single analog-to-digital converter may be used to measure temperature, voltage, bias current, transmit power and received power. In that case, in order to convert each digitized result into the appropriate natural unit for the data source, the ALU must be provided with the appropriate pairs of coefficients m and c for the respective data source. In accordance with the present invention, a numerical value conversion device is provided to support numerical value conversion of digital input values derived from multiple data sources, also referred to as input channels. The numerical value conversion device includes a look-up table storing coefficients associated with each data source. In this manner, the appropriate coefficients for the digital input value being processed can be retrieved by indexing the look-up table and providing the coefficients to the ALU. Furthermore, in accordance with the present invention, the numerical value conversion device includes an ALU that supports digital input values (operands) having variable resolution or variable bit-length. The ALU is also capable of providing digital output values having variable resolution. Finally, the numerical value conversion device includes an ALU that is saturation-limited so that a reasonable output value is always provided regardless of possible errors in the digital input values. FIG. 7 is a schematic diagram of a device for performing numerical value conversion using a look-up table for coefficient storage and a saturation limited ALU according to one embodiment of the present invention. Referring to FIG. 7, the numerical value conversion device receives a source of digital input values from an ADC 72. The digital input values in arbitrary units are provided to an ALU 76 on a bus 74. In the present embodiment, ADC 72 is disposed to digitize multiple analog data sources. In the present description, each analog data source is also referred to as an input channel or a measurement parameter. The digital input values provided by ADC 72 on bus 74 can be digitized values of the various analog data sources provided in sequence or in random order. In one embodiment, the numerical value conversion device of the present invention is incorporated in an optical transceiver and ADC 72 is disposed to measure and digitize the following measurement parameters: temperature, voltage, bias current, transmit power and received power. Therefore, ALU 76 will receive from ADC 72 digital input values belonging to the different measurement parameters being measured in sequence. In the numerical value conversion device of the present invention, ALU 76 receives digital input values belonging to the different analog data sources (measurement parameters) being measured by ADC 72 where the digital input values are expressed in arbitrary units. ALU 76 operates to convert the digital input values into the appropriate natural units for the measurement parameters. For example, a digital input value of temperature should be converted into a value in degree Centigrade and a digital input value of voltage should be converted into a value in volts. For each measurement parameter, a separate set of coefficients must be used. In the present embodiment, ALU 76 receives the coefficients for performing the numerical value conversion from a look-up table 80. In the present embodiment, the arbitrary unit of the digital input values is assumed to have a linear relationship with the respective natural unit described by Equation (1) above. Thus, look-up table 80 stores pairs of slope m and offset c coefficients for each measurement parameter measured by ADC 72. Look-up table 80 is indexed by an indexing parameter P2 for selecting one set of slope and offset coefficients. Depending on the digital input value currently being provided to ALU 76, indexing parameter P2 operates to retrieve a selected pair of slope and offset coefficients and provide the coefficients on bus 78 to ALU 76. Using the selected coefficients, ALU 76 performs the numerical conversion of the digital input values received on bus 74 based on Equation (1) above. A digital output value in the desired natural unit is provided on an output port 82 of ALU 76. Look-up table 80 can be implemented as a memory unit, such as a random-access memory. Thus, in accordance with the present invention, a single ALU is used for converting digital input values belonging to multiple measurement parameters (analog data sources). Depending on the measurement parameter currently being supplied to ALU 76, the appropriate set of coefficients is retrieved from look-up table 80 and fed to ALU 76 for use in the conversion of the digital input value. Furthermore, in the present embodiment, ALU 76 is disposed to support digital input values (operands) having variable resolution or variable bit-length. This feature is particularly useful as ADC 72 does not necessarily digitize each analog data source to a digital result with identical numbers of bits. For instance, some analog data source may be digitized to a finer resolution than others. For example, temperature measurements might be digitized to an eight-bit resolution, allowing a range from −128 to +127 Centigrade (one degree Centigrade resolution). In the same system, voltage measurements might be digitized to a 12-bit resolution, allowing a range of 0 to 4095 millivolts (one millivolt resolution). ALU 76 therefore supports and converts ADC results (also referred to as “operands”) with different bit-length or with variable resolution. The ALU is also capable of providing digital output values having variable resolution. FIG. 8 is a schematic unit of an ALU implementing variable bit-length operands according to one embodiment of the present invention. Referring to FIG. 8, an ALU 92 receives input values (operands) having variable bit-lengths and produces a native ALU result in P bits. In the present embodiment, ALU 92 is assumed to produce a native 12-bit result, denoted as alu_result[11:0] in FIG. 8. The host processor may require the ALU results to be presented in Q bits. In the present embodiment, the host processor is assumed to require an ALU result of 16-bit. To accommodate the variable bit-length operands, the ALU operates to select a portion or all of the P bits of the native ALU result and add trailing zeros to the selected portion to generate a final ALU result of the desired bit-length. For example, when the input values are digitized voltage values expressed in all 12 bits of the native ALU result, the ALU circuit pads the 12-bit ALU result with additional four zeros to generate a final 16-bit ALU result. The four zeros are added as least significant bits of the final 16-bit ALU result. Alternately, when the input values are digitized temperature values expressed in only 8 bits of the native ALU result, the least significant 8 bits of the 12-bit native ALU result (alu_result[7:0]) is selected. The ALU circuit pads the selected 8-bit ALU result with additional eight zeros to generate a final 16-bit ALU result. The eight zeros are added as least significant bits of the final 16-bit ALU result. By varying the choice of the bits selected from the native ALU result and by changing the number of padding zeros, the ALU can support variable bit-length operands and can also provide results with varying bit-length. Finally, in the present embodiment, the ALU is saturation-limited to ensure that a reasonable output value is always provided by the numerical value conversion device of the present invention regardless of possible errors in the digital input values. Conversion errors can occur when the digital input values delivered to the ALU are beyond the ALU's normal scope of computation. For example, consider what occurs if a voltage measurement is converted according to the formula: Vn=100VADC, where VADC is the digital input value in arbitrary unit of a digitized voltage measurement and Vn is the converted value in the unit millivolt. Assume for the present example that Vn is a 12-bit value and VADC is an 8-bit value. Vn's maximum value is therefore 4095 (that is, 212−1). If VADC exceeds 50, then Vn will exceed 4095. This imposes a maximum bound on the values of VADC. In unusual circumstances, the maximum value of VADC might be violated, as a result of an erratic or excessive input or some other conditions. When this occurs, the converted value Vn will be beyond its maximum value and the ALU will return a faulty result. Thus, in the present embodiment, the numerical value conversion device imposes a saturation limitation on the ALU's output result. Referring to FIG. 7, output port 82 of ALU 76 is coupled to a limit check circuit 86 and a clamp circuit 84. Limit check circuit 86 monitors the output result from ALU 76. Clamp circuit 84, depending on the control signal provided by limit check circuit 86, will either pass the ALU output result onto output port 88 or clamp the ALU output result to a predetermined maximum value, such as 4095 in the above example. In the present embodiment, the numerical value conversion device also operates to limit the lower bound of the ALU result. Thus, if the conversion process produces a negative result, the limit check circuit will detect the condition and instruct the clamp circuit to clamp the output result to zero. The lower-bound saturation limitation is optional and can be included in the numerical value conversion device of the present invention as desired. The operation of the numerical value conversion device of FIG. 7 is as follows. ADC 72 provides a binary representation of a digital input value of one of several measurement parameters being measured by the ADC. The binary representations for the different analog data source may be of different bit lengths. The numerical value conversion device, using indexing parameter P2, retrieves a pair of coefficients (m, c) from look-up table 80 to ALU 76. The value of indexing parameter P2 is based on the measurement parameter of the ADC currently being measured. ALU 76 performs the computation on the digital input value provided on bus 74 based on the equation: Dn=mDADC+c, Eq. (4) using the coefficients m, c provided by look-up table 80. DADC is the digital input value and Dn is the digital output value in the desired natural unit. After the value Dn is computed, limit check circuit 86 determines if the ALU's result (Dn) is greater than a maximum value or less than a minimum value. If the ALU's result (Dn) exceeds the maximum value, limit check circuit 86 instructs clamp circuit 84 to output a predetermined result, usually the maximum allowable output value, on output port 88. If the ALU's result (Dn) is less than the minimum value, limit check circuit 86 instructs clamp circuit 84 to output a predetermined result, usually the minimum allowable output value or zero, on output port 88. If the ALU's result (Dn) is within the maximum value and the minimum value, no instruction is issued from limit check circuit 86 and clamp circuit 84 passes the value Dn received on port 82 on output port 88. In this manner, the numerical value conversion device of the present invention operates to convert a digital input value in arbitrary unit into a digital output value in a natural unit which digital output value is guaranteed to contain a reasonable value. FIG. 9 is a schematic diagram of one embodiment of a clamp circuit which can be used in the numerical value conversion device of the present invention. Referring to FIG. 9, ALU 99 provides an ALU result which is coupled to a first comparator 100. The ALU result is compared with a predetermined minimum value to determine if the ALU result is less than the predetermined minimum value. If the ALU result is less than the predetermined minimum value, the output of comparator 100 is asserted. The ALU result is also coupled to a second comparator 101. The ALU result is compared with a predetermined maximum value to determine if the ALU result is greater than the predetermined maximum value. If the ALU result is greater than the predetermined maximum value, the output of comparator 101 is asserted. The output signals from comparator 100 and comparator 101 are coupled to a three-input multiplexor 102 as select signals. Multiplexor 102 receives a minimum allowable output value, a maximum allowable output value, and the ALU result as input signals from ALU 99. Depending on the values of the select signals, one of the three input signals will be selected. If the output signal from comparator 100 is asserted, then multiplexor 102 will select the minimum allowable output value as the clamped result. If the output signal from comparator 101 is asserted, then multiplexor 102 will select the maximum allowable output value as the clamped result. If neither output signals are asserted, then multiplexor 102 will select the ALU result as the clamped result. That is, the unmodified ALU result is passed through the clamp circuit. According to another aspect of the present invention, ALU 76 is implemented as a fixed-function ALU. That is, ALU 76 is designed to be able to only perform the multiplication and addition operations required to implement the slope/offset calculation in equation (4) above. By using a fixed-function ALU, instead of a conventional full-function ALU, the size of the ALU can be minimized. A numerical value conversion device using a fixed function ALU is particularly advantageous when high speed operation and small device size are desired. In particular, a fixed-function ALU is suitable when the device needs to be constructed as a small form-factor integrated circuit. In the above description, the numerical value conversion device performs linear conversions between the digital input values in the arbitrary unit and digital output values in the natural unit. In other embodiments, the numerical value conversion device can also operate to perform non-linear conversions using a piecewise-linear approach as described above. In the present embodiment, the numerical value conversion device of the present invention provides numerous advantages. First, a memory, in the form of a look-up table, is used to store separate coefficients for each analog data source or measurement parameter being processed. In this manner, a single ALU can be used to convert digital values from multiple analog data sources. Second, the numerical value conversion device can support digital input values having variable resolution operands. Thus, the device can support multiple analog input channels that are digitized to different resolutions. Third, the numerical value conversion device is saturation-limited so that a reasonable value is returned regardless of possible errors in the digital input values. Lastly, when a fixed-function ALU is used, the numerical value conversion device can be optimized in speed and size. The above detailed descriptions are provided to illustrate specific embodiments of the present invention and are not intended to be limiting. Numerous modifications and variations within the scope of the present invention are possible. The present invention is defined by the appended claims. | <SOH> FIELD OF THE INVENTION <EOH>The invention relates to a device for performing numerical value conversion and, in particular, to a device for performing numerical value conversion including an arithmetic logic unit that is saturation limited and supports variable resolution operands. | <SOH> SUMMARY OF THE INVENTION <EOH>According to one embodiment of the present invention, a device for performing numerical value conversion of a digital input value in a first unit to a second unit being a natural unit where the first unit is related to the second unit by a first equation is disclosed. The digital input value is a digitized value of a first measurement parameter among multiple measurement parameters. The device includes a look-up table storing an array of coefficients for performing the numerical value conversion from the first unit to the second unit for each of the multiple measurement parameters. The look-up table is indexed using a first parameter to provide a selected coefficient where the first parameter is indicative of the first measurement parameter. The device further includes an arithmetic logic unit receiving the digital input value in the first unit and the selected coefficient from the look-up table. The arithmetic logic unit performs the numerical value conversion based on the first equation and using the selected coefficient to compute a digital output value in the second unit. Finally, the device includes a saturation-limit circuit coupled to receive the digital output value in the second unit from the arithmetic logic unit and provide a predetermined final output value when the digital output value exceeds a predetermined minimum or maximum value. In another embodiment, the arithmetic logic unit is a fixed-function ALU capable of multiplication and addition operations only. In yet another embodiment, the arithmetic logic unit is disposed to support digital input values having variable bit length. According to another aspect of the present invention, a method for performing numerical value conversion of a digital input value in a first unit to a second unit being a natural unit where the first unit is related to the second unit by a first equation is disclosed. The digital input value is a digitized value of a first measurement parameter among multiple measurement parameters. The method includes storing an array of coefficients in a look-up table for performing the numerical value conversion from the first unit to the second unit where each of the multiple measurement parameters is associated with at least one coefficient in the array of coefficients, indexing the look-up table using a first parameter being indicative of the first measurement parameter to provide a selected coefficient, providing the digital input value and the selected coefficient to an arithmetic logic unit, and performing a numerical value conversion at the arithmetic logic unit based on the first equation and using the selected coefficient to compute a digital output value in the second unit from the digital input value in the first unit. The method further includes determining if the digital output value exceeds a predetermined maximum value, providing a first predetermined value as the final output value when the digital output value exceeds the predetermined maximum value, and providing the digital output value as the final output value when the digital output value does not exceed the predetermined maximum value. In another embodiment, the method further includes determining if the digital output value is less than a predetermined minimum value, providing a second predetermined value as the final output value when the digital output value is less than the predetermined minimum value, and providing the digital output value as the final output value when the digital output value exceeds the predetermined minimum value. The present invention is better understood upon consideration of the detailed description below and the accompanying drawings. | 20040115 | 20080701 | 20050616 | 58115.0 | 0 | NGO, CHUONG D | NUMERICAL VALUE CONVERSION USING A SATURATION LIMITED ARITHMETIC LOGIC UNIT SUPPORTING VARIABLE RESOLUTION OPERANDS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,760,118 | ACCEPTED | Condenser optic with sacrificial reflective surface | Employing collector optics that have a sacrificial reflective surface can significantly prolong the useful life of the collector optics and the overall performance of the condenser in which the collector optics are incorporated. The collector optics are normally subject to erosion by debris from laser plasma source of radiation. The presence of an upper sacrificial reflective surface over the underlying reflective surface effectively increases the life of the optics while relaxing the constraints on the radiation source. Spatial and temporally varying reflectivity that results from the use of the sacrificial reflective surface can be accommodated by proper condenser design. | 1. A condenser system for use with a camera to collect and image radiation to a mask comprising: a source of radiation; and at least one collector mirror facing the source of radiation wherein the at least one collector mirror comprises a substrate, an underlying reflective surface, and an upper sacrificial reflective surface. 2. The condenser system of claim 1 wherein the at least one collector mirror does not include a passivating overcoat. 3. The condenser system of claim 1 wherein the source of radiation is a laser plasma source. 4. The condenser system of claim 1 wherein the source of radiation generates EUV radiation. 5. The condenser system of claim 4 wherein the underlying reflective surface has a normal incidence reflectivity of at least about 30% of the EUV radiation. 6. The condenser system of claim 1 wherein the underlying reflective surface comprises a first multilayer film that is deposited on a surface of the substrate and wherein the sacrificial reflective surface is a second multilayer film that is deposited on a surface of the underlying reflective surface. 7. The condenser system of claim 6 wherein (i) the first multilayer film comprises alternating layers of first material having a first refractive index and a second material having a second refractive index that is larger than that of the first material and (ii) the second multilayer film comprises alternating layers of third material having a third refractive index and a fourth material having a fourth refractive index that is larger than that of the third material. 8. The condenser system of claim 7 wherein the first multilayer film comprises about 20 to 80 layer pairs and the second multilayer film comprises about 100 to 400 layer pairs. 9. The condenser system of claim 8 wherein the first multilayer film has a periodicity of about 5 nm to 30 nm and the second multilayer film has a periodicity of about 5 nm to 30 nm. 10. The condenser system of claim 6 wherein the first multilayer film comprises alternating layers of molybdenum and silicon and the second multilayer film comprises alternating layers of molybdenum and silicon. 11. The condenser system of claim 10 wherein the source of radiation generates EUV radiation. 12. The condenser system of claim 1 wherein the system is for use with a ringfield camera and wherein the at least one collector mirror comprises at least two substantially equal radial segments of a parent aspheric mirror, each having one focus at the radiation source and a curved line focus filling the object field of the camera at the radius of the ringfield and each producing a beam of radiation. 13. The condenser system of claim 12 further comprising: a corresponding number of sets of correcting mirror means which are capable of translation or rotation, or both, such that all of the beams of radiation pass through the entrance pupil of the camera and form a coincident arc image at the ringfield radius, wherein at least one of the correcting mirrors of each set, or a mirror that is common to said sets of mirrors, from which the radiation emanates, is a concave relay mirror that is positioned to shape a beam segment having a chord angle of about 25 to 85 degrees into a second beam segment having a chord angle of about 0 to 60 degrees, wherein the distance from the collector mirrors to the concave relay mirror is equal to 3 to 10 times the distance from the concave relay mirror to the mask. 14. The condenser system of claim 13 wherein the at least one collector mirror comprises six substantially equal radial segments of a parent aspheric mirror. 15. A condenser system having a set of mirrors for collecting extreme ultra-violet (EUV) radiation from a radiation source that forms a source image and having correcting mirrors which are capable of translating or rotating, or both, one or more beams from said set of mirrors and are capable of modifying the convergence of the one or more beams or the size of the source image, or both, and wherein the system includes at least one collector mirror facing a source of EUV radiation wherein the at least one collector mirror comprises a substrate, an underlying reflective surface, and an upper sacrificial reflective surface. 16. The condenser system of claim 15 wherein the at least one collector mirror does not include a passivating overcoat. 17. The condenser system of claim 15 wherein the radiation source is a laser plasma source. 18. The condenser system of claim 15 wherein the underlying reflective surface has a normal incidence reflectivity of at least about 30% of the EUV radiation. 19. The condenser system of claim 15 wherein the underlying reflective surface comprises a first multilayer film that is deposited on a surface of the substrate and wherein the sacrificial reflective surface is a second multilayer film that is deposited on a surface of the underlying reflective surface. 20. The condenser system of claim 19 wherein (i) the first multilayer film comprises alternating layers of first material having a first refractive index and a second material having a second refractive index that is larger than that of the first material and (ii) the second multilayer film comprises alternating layers of third material having a third refractive index and a fourth material having a fourth refractive index that is larger than that of the third material. 21. The condenser system of claim 20 wherein the first multilayer film comprises about 20 to 80 layer pairs and the second multilayer film comprises about 100 to 400 layer pairs. 22. The condenser system of claim 21 wherein the first multilayer film has a periodicity of about 5 nm to 30 nm and the second multilayer film has a periodicity of about 5 nm to 30 nm. 23. The condenser system of claim 19 wherein the first multilayer film comprises alternating layers of molybdenum and silicon and the second multilayer film comprises alternating layers of molybdenum and silicon. 24. A method of preparing a collector mirror of a condenser system for collecting radiation of a selected wavelength from a source of radiation that comprises the steps of: (a) depositing a first multilayer film on a substrate such that the film achieves a desired reflectance with respect to a first radiation light having a first wavelength; and (b) depositing a second multilayer film on the first multilayer film, wherein the second multiplayer film also reflects the first radiation light. 25. The method of claim 24 wherein the first multilayer film comprises an underlying reflective surface and wherein the second multilayer film comprises an upper sacrificial reflective surface. 26. The method of claim 24 wherein the collector mirror does not include a passivating overcoat. 27. The method of claim 24 wherein step (a) comprises depositing a first multilayer film on a substrate such that the film achieves a reflectance of at least 30% with respect to the first radiation light. 28. The method of claim 24 wherein the first radiation light is EUV radiation. 29. The method of claim 28 wherein the first multilayer film has a normal incidence reflectivity of at least about 30% of the EUV radiation. 30. The method of claim 28 wherein the second multilayer film has a thickness that is at least 2 times the thickness of the first multilayer film. 31. The method of claim 24 wherein (i) the first multilayer film comprises alternating layers of first material having a first refractive index and a second material having a second refractive index that is larger than that of the first material and (ii) the second multilayer film comprises alternating layers of third material having a third refractive index and a fourth material having a fourth refractive index that is larger than that of the third material. 32. The method of claim 31 wherein the first multilayer film comprises about 20 to 80 layer pairs and the second multilayer film comprises about 100 to 400 layer pairs. 33. The method of claim 32 wherein the first multilayer film has a periodicity of about 5 nm to 30 nm and the second multilayer film has a periodicity of about 5 nm to 30 nm. 34. The method of claim 31 wherein the first multilayer film comprises alternating layers of molybdenum and silicon and the second multilayer film comprises alternating layers of molybdenum and silicon. 35. The method of claim 34 wherein the first radiation light is EUV radiation. 36. The method of claim 24 wherein the collector mirror comprises at least two substantially equal radial segments of a parent aspheric mirror. 37. The method of claim 36 wherein the collector mirror comprises six substantially equal radial segments of a parent aspheric mirror. | This invention was made with Government support under Contract No. DE-AC04-94AL85000 awarded by the U.S. Department of Energy to Sandia Corporation. The Government has certain rights to the invention. FIELD OF THE INVENTION EUV lithography (EUVL) is an emerging technology in the microelectronics industry. It is one of the leading candidates for the fabrication of devices with feature sizes of 45 nm and smaller. This invention relates to techniques for extending the lifetime of the plasma-facing condenser surface of EUVL devices. BACKGROUND OF THE INVENTION In general, lithography refers to processes for pattern transfer between various media. A lithographic coating is generally a radiation-sensitized coating suitable for receiving a cast image of the subject pattern. Once the image is cast, it is indelibly formed on the coating. The recorded image may be either a negative or a positive of the subject pattern. Typically, a “transparency” of the subject pattern is made having areas which are selectively transparent or opaque to the impinging radiation. Exposure of the coating through the transparency placed in close longitudinal proximity to the coating causes the exposed area of the coating to become selectively crosslinked and consequently either more or less soluble (depending on the coating) in a particular solvent developer. The more soluble, i.e., uncrosslinked, areas are removed in the developing process to leave the pattern image in the coating as less soluble crosslinked polymer. Projection lithography is a powerful and essential tool for microelectronics processing and has supplanted proximity printing. “Long” or “soft” x-rays (a.k.a. Extreme UV) (wavelength rate of 10 to 20 nm) are now at the forefront of research in efforts to achieve smaller transferred feature sizes. With projection photolithography, a reticle (or mask) is imaged through a reduction-projection (demagnifying) lens onto a wafer. Reticles for EUV projection lithography typically comprise a glass substrate coated with an EUV absorbing material covering portions of the reflective surface. In operation, EUV radiation from the illumination system (condenser) is projected toward the surface of the reticle and radiation is reflected from those areas of the reticle reflective surface which are exposed, i.e., not covered by the EUV absorbing material. The reflected radiation is re-imaged to the wafer using a reflective optical system and the pattern from the reticle is effectively transcribed to the wafer. A source of EUV radiation is the laser-produced plasma EUV source, which depends upon a high power, pulsed laser (e.g., a yttrium aluminum garnet (“YAG”) laser, or an excimer laser, delivering 500 to 1,000 watts of power to a 50 μm to 250 μm spot, thereby heating a source material to, for example 250,000° C., to emit EUV radiation from the resulting plasma. Plasma sources are compact, and may be dedicated to a single production line so that malfunction does not close down the entire plant. A stepper employing a laser-produced plasma source is relatively inexpensive and could be housed in existing facilities. It is expected that EUV sources suitable for photolithography that provide bright, incoherent EUV and that employ physics quite different from that of the laser-produced plasma source will be developed. One such source under development is the EUV discharge source. EUV lithography machines for producing integrated circuit components are described, for example, in U.S. Pat. No. 6,031,598 to Tichenor et al. Referring to FIG. 7, the EUV lithography machine comprises a main vacuum or projection chamber 102 and a source vacuum chamber 104. Source chamber 104 is connected to main chamber 102 through an airlock valve (not shown) which permits either chamber to be accessed without venting or contaminating the environment of the other chamber. Typically, a laser beam 130 is directed by turning mirror 132 into the source chamber 104. A high density gas, such as xenon, is injected into the plasma generator 136 through gas supply 134 and the interaction of the laser beam 130, and gas supply 134 creates a plasma giving off the illumination used in EUV lithography. The EUV radiation is collected by segmented collector 138, that collects about 30% of the available EUV light, and the radiation 140 is directed toward the pupil optics 142. The pupil optics consists of long narrow mirrors arranged to focus the rays from the collector at grazing angels onto an imaging mirror 143 that redirects the illumination beam through filter/window 144. Filter 144 passes only the desired EUV wavelengths and excludes scattered laser beam light in chamber 104. The illumination beam 145 is then reflected from the relay optics 146, another grazing angel mirror, and then illuminates the pattern on the reticle 148. Mirrors 138, 142, 143, and 146 together comprise the complete illumination system or condenser. The reflected pattern from the reticle 148 then passes through the projection optics 150 which reduces the image size to that desired for printing on the wafer. After exiting the projection optics 150, the beam passes through vacuum window 152. The beam then prints its pattern on wafer 154. Debris generated by the plasma source is one of the most significant impediments to the successful development of photolithography. In particular, debris tends to erode the optics used to collect the EUV light which severely degrades their EUV reflectance. Ultimately, the erosion will reduce the optics' efficiency to a point where they must be replaced frequently. The art is in search of techniques that address this problem. SUMMARY OF THE INVENTION The present invention is based in part on the recognition that employing collector optics that have a sacrificial reflective surface can significantly enhance the useful life of the collector optics and subsequently improve the overall performance of the condenser in which the collector optics are incorporated. In one embodiment, the invention is directed to a condenser system for use with a camera to collect and image radiation to a mask the includes: a source of radiation; and at least one collector mirror facing the source of radiation wherein the at least one collector mirror comprises a substrate, an underlying reflective surface, and an upper sacrificial reflective surface. In another embodiment, the invention is directed to a condenser system having a set of mirrors for collecting extreme ultra-violet (EUV) radiation from a radiation source that forms a source image correcting mirrors which are capable of translating or rotating, or both, one or more beams from said set of mirrors and are capable of modifying the convergence of the one or more beams or the size of the source image, or both, and wherein the system includes at least one collector mirror facing a source of EUV radiation wherein the at least one collector mirror comprises a substrate, an underlying reflective surface, and an upper sacrificial reflective surface. In a further embodiment, the invention is directed to a method of preparing a collector mirror of a condenser system for collecting radiation of a selected wavelength from a source of radiation that includes the steps of: (a) depositing a first multilayer film on a substrate such that the film achieves a desired reflectance with respect to a first radiation light having a first wavelength; and (b) depositing a second multilayer film on the first multilayer film, wherein the second multiplayer film also reflects the first radiation light. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 shows the a collection mirror formed of a bilayer stack; FIG. 2A is a perspective view of an EUV photolithography system showing the beams going through its set of correcting mirrors and showing the interaction of the beam with the camera; FIGS. 2B and 2C illustrate a steeply tilted biconvex mirror; FIGS. 3A and 3B illustrate a beam segment before and after reshaping; FIG. 4 is a side-view of the condenser system without correcting mirrors, showing the reimaging of the point source into a ringfield with the images crossing over the center line of the system; FIG. 5 is another side-view showing the geometries of the mirrors and the beams in more detail for this embodiment; FIG. 6A is a graph of calculated reflectance for Mo/Si multilayer vs. erosion and 6B shows the local oscillations that occur due to alternating Mo and Si layers, respectively; and FIG. 7 shows a prior art photolithography device. DESCRIPTION OF PREFERRED EMBODIMENTS The present invention is directed to condenser systems that employ collector mirrors with sacrificial reflective surfaces. While the invention will be described with respect to a particular condenser, it is understood that the collector mirrors with the sacrificial reflective surfaces can be used with any condenser particularly those that are used in photolithography. Condenser illumination systems include, for example, Kohler and critical illumination condenser systems. Condensers can be coupled to a variety of radiation sources including, for example, line-shaped plasma source or an arc-shaped discharge source. Condenser are described, for example, in U.S. Pat. No. 5,361,292 to Sweatt, U.S. Pat. No. 5,737,137 to Cohen et al., U.S. Pat. No. 6,033,079 to Hudyma, and U.S. Pat. Nos. 6,118,577, 6,210,865, 6,285,737, and 6,469,827 all to Sweatt et al., which are incorporated herein by reference. By “sacrificial reflective surface” formed on a collection mirror is meant a multilayer reflective stack that is fabricated on top of an underlying reflective surface of the collection mirror. In the case of a collection mirror for EUV radiation, the collection mirror itself comprises a stack of alternating layers of two or more materials that are deposited on a substrate. Thus, the “sacrificial reflective surface” can be viewed as a second stack, which also comprises alternating layers of two or more materials, that is fabricated on the first stack of the collection mirror. The materials that form the second stack can be different from those that form the first stack, however, for simplicity in design and fabrication, the materials and their thicknesses that form the second stack are preferably the same. A critical feature of the invention is that the upper sacrificial reflective surface is not intended to be a permanent, protective overcoat shielding the underlying reflective surface of the collection mirror from oxidation or degradation due to exposure to the radiation source. These prior art protective overcoats are also referred to as “passivating overcoats” which are described, for instance, in U.S. Pat. No. 5,958,605 to Montcalm et al., which is incorporated herein. The inventive sacrificial reflective surface does not require such passiviating or capping coatings, rather, with the present invention the sacrificial reflective surface is intended to gradually degrade in much the same fashion as the underlying reflective surface during normal operations. Of course, the sacrificial reflective surface will erode first before the underlying reflective surface is exposed. In the case where the bilayers of the sacrificial reflective surface are made of the same materials as that of the underlying reflective surface, the individual bilayers of the sacrificial multilayer will also have substantially the same thickness and periodicity as bilayers of the underlying reflective surface. FIG. 1 is a schematic of a collector mirror that includes the inventive sacrificial reflective surface or stack. The structure of the collector mirror includes a multilayer stack 12 that is deposited on the upper surface of substrate 10. The substrate 10 serves as a support and can be made of any suitable material including, for example, silicon or glass. The stack 12 comprises an (i) underlying reflective surface 14 that is fabricated directly on the substrate 10 and (ii) an upper sacrificial reflective surface 16 that is fabricated on the surface 14. (As is apparent, FIG. 1 is illustrative since the number of layers in the stack 12 is actually much greater.) The multilayer reflection stack 12 is designed to reflect at the wavelength of interest and is formed of alternating layers of two or more materials that can be deposited by conventional thin-film and multilayer techniques. Preferred materials include, for example, molybdenum (Mo), silicon (Si), tungsten (W), carbon (C), beryllium (Be), ruthenium (Ru), B4C, Mo2C, titanium (Ti), and vanadium (V). Preferred stacks are formed from alternating layers of two materials that are selected from the following list of seven pairs: Mo—Si, W—C, Mo—Be, Ru—B4C, Mo2C—Si, Ti—C, and V—C. Alternating layers of Mo and Si (Mo/Si) are particularly preferred for EUV applications, e.g., radiation with a wavelength on the order of 10 nm. As further described herein, the reflectance of radiation from a multilayer reflective stack is proportional to the number of bilayers that form the stack but the reflectance does reach a plateau once the certain number of bilayers is reached. A larger number of layers will provide higher reflectivity at the cost of lower angular and temporal bandwidth. The number of bilayer will depend on the materials used and will typically range from about 10 to 200 and preferably from about 20 to 80. Moreover, the bilayers will typically have a bilayer periodicity of about 2 nm to 100 nm and preferably from about 5 nm to 30 nm. By “periodicity” is meant the thickness of one bilayer. In fabricating a collection mirror that incorporates the sacrificial reflective surface for EUV lithography, it is first necessary to design and deposit the underlying reflective surface or stack onto a substrate. A preferred underlying reflective surface comprises alternating bilayers described above. For EUV applications, the underlying reflective surface will typically comprise from 20 to 80 bilayers which produces a stack that should reflect approximately 20% to 80% and preferably at least 30% EUV and has a normal incidence reflectivity of EUV of at least about 30%. A preferred stack comprises 40 to 60 bilayers of Mo and Si which reflects typically 60% to 70% EUV. For EUV lithography, the expected maximum EUV reflectance from plasma-facing collection mirrors will typically be within these ranges. The EUV reflectance of the stack will not improve insignificantly beyond this even if more bilayers are added. Next, the a sacrificial reflective stack comprising Mo and Si bilayers are formed over the underlying reflective surface. For EUV applications, the sacrificial reflective surface will typically comprise from 40 to 400 and preferably from 60 to 200 number of bilayers of Mo and Si. In actual production, there is no disruption between the completion of the underlying reflective surface and initiation of the sacrificial reflective surface. In effect, the sacrificial reflective surface can be construed as the outer portion of bilayer stack that is not necessary for the mirror to attain the desired or maximum EUV reflectance. While the deposition of the sacrificial reflective surface or stack over the underlying reflective surface will not enhance the reflectance of the collection mirror, the sacrificial reflective surface will prolong the useful life of the collection mirror. In the preferred embodiment, the thickness of the sacrificial reflective stack is at least 2 times the thickness of the underlying reflective surface. For EUV lithography applications, the EUV reflectance of a collection mirror as a function of the number of bilayers deposited on the mirror can be simulated, however, as a practical matter, theoretically perfect reflectivities are never achieved. In practice the “real reflectivities” of the mirror are measured during actual production and the total number of bilayers, designated as “x,” needed to achieve the maximum reflectance is determined, which corresponds to the underlying reflective surface. With the present invention, the collection mirrors are fabricated by first depositing x number of bilayers on a substrate and then depositing an additional number of bilayers, designated as “y,” as the sacrificial reflective surface. Y can be represented as fractions or multiple of x. In preferred embodiments, y is equal to at least twice x and preferably equal to three or four times x. The durability of the inventive collection mirror will be proportional to the thickness the sacrificial reflective surface or stack. As is apparent, the physical characteristics of the materials used to form the multilayers of the sacrificial reflective surface will influence overall durability. From a practical standpoint, the number of multilayers that can be deposited will be limited by the stress that is created within the stack; the level of stress increases with the number of bilayers. At some point the stresses will either deform the optic, until it is out of specification, or more likely, cause the multilayer to fail and peel off of the substrate. Low stress multilayers are therefore preferred. The roughening of the surface with increased number of multilayers may also limit the number of bilayers that can be deposited on the stack. Collection mirrors employing the sacrificial reflective surface can be incorporated in suitable EUV lithography systems such as the one shown in FIG. 2A. The radiation is collected from the source 22 by collection mirror segments 30 (referred to collectively as the “C1” mirrors) which create arc images that are in turn are rotated by roof mirror pairs illustrated collectively as mirrors 40 and 50 (referred herein as the “C2” and “C3” mirrors, respectively). (As further described herein, the mirror segments 30 have the sacrificial multilayers.) Beams of radiation reflected from mirrors 50 are reflected by a toric mirror 60 (or C4 mirror) to deliver six overlapped ringfield segments onto reflective mask 70. At least two segments of the parent mirror 30 are employed. Typically, the parent mirror is partitioned into 2 to 12 segments, preferably into 5 to 8 segments, and most preferably into 6 segments as shown. As an example, mirror 31 creates an arc image and roof mirror pair 41 and 51 rotates the arc image to fit the slit image and translate it to the proper position. Similar arc images are created and processed by mirror combinations 32, 42, and 52, and so on. Mirrors 41, 42, and 43 are parts of different and unique channels; and the group of mirrors 44, 45, and 46 is a mirror image of the group of mirrors 41, 42, and 43, respectively. The distance from the C3 mirrors defining the condenser's pupil to the C4 mirror should be 3 to 10 times as long as the distance from the C4 mirror to mask 70. An illustrative arc 71 is shown on mask 70. The EUV lithography system further includes a ringfield camera 77 having a set of mirrors which images the mask using the radiation onto wafer 78. As is apparent, the C4 mirror follows the real entrance pupil. Each of the six pairs of C2 and C3 mirrors act as a roof-mirror pair that rotate and translate the 6 channels so that they overlap. Specifically, the C2 and C3 mirror pairs rotate the arcuate images produced by the C1 mirrors so that they can be superimposed at the mask plane. The C2 mirrors are preferably flat and are used at grazing incidence, which is preferably 82 degrees angle of incidence for the chief ray. The chief ray angle of incidence is preferably constrained to have the same angle of incidence at each C2 mirror so that the reflectivities will be the same. Further, the C1 angles are preferably tilted about the source to allow the angles of incidence to be the same at C1. The C3 mirrors typically have weak convex spherical surfaces which relay the C1 arcuate images onto the mask. The C3 mirrors are located at the system pupil (i.e., where the azimuthal beam cross-section is a minimum) to facilitate packaging and are tilted to overlay the arcuate images from the six channels. The C3 mirrors are preferably positioned as close together as possible (approximately 3 mm separates the clear apertures) to maximize the amount of EUV that can be directed into the camera. FIG. 2C depicts the C4 field mirror 60 which is toroidally (or elliptically) shaped. As shown, a beam cross section 62 from the condenser is reflected from the surface of the mirror 60 to form a curved slit illumination 71 on moving mask 70 (FIG. 1A). Beam 75 is propagated from the mask into the camera. The toroid images the real pupil containing the C3 mirrors into the entrance pupil of the camera. The focal length of mirror C4 can be determined from the lens maker's equation. The radii of curvature Rx and Ry are functions of the focal length and the angle of incidence θ, as determined by Coddington's equation. The tilt angle also tends to distort the cross-section of an incident beam, with the distortion increasing with angle of incidence. The source of this distortion is shown in FIG. 2B that illustrates an embodiment of the C4 biconcave mirror where Ry is 0.6 m and Rx is 9.0 m. As is apparent, remapping occurs when the middle of the 50 degrees segment is reflected off the bottom of the nearly cylindrical, steeply tilted concave mirror while the ends reflect off the edges of the mirror which are higher. FIGS. 3A and 3B shows a beam segment before and after reshaping. Note that the ends of the 50 degrees segment curl far more than those of the 28 degrees segment. Condensers of the present invention are particularly suited for use in projection lithography for fabricating integrated devices that comprise at least one element having a dimension of ≦0.251 μm and preferably ≦0.18 μm. The process comprises construction of a plurality of successive levels by lithographic delineation using a mask pattern that is illuminated to produce a corresponding pattern image on the device being fabricated, ultimately to result in removal of or addition of material in the pattern image regions. Typically, where lithographic delineation is by projection, the collected radiation is processed to accommodate imaging optics of a projection camera and image quality that is substantially equal in the scan and cross-scan directions, and smoothly varying as the space between adjacent lines varies. In a preferred embodiment, projection comprises ringfield scanning comprising illumination of a straight or arcuate region of a projection mask. In another preferred embodiment, projection comprises reduction ringfield scanning in which an imaged arcuate region on the image plane is of reduced size relative to that of the subject arcuate region so that the imaged pattern is reduced in size relative to the mask region. As shown in FIG. 4, the illuminator or collecting mirrors are composed of six off-axis segments of an aspheric mirror, each 50 degrees wide, producing six beams which each cross over the system axis or centerline 11 as defined by the source and the center of the parent mirror. The parent aspheric mirror 10 images the “point” source 12 into a ring image 14. Therefore, its cross-section in the r-z plane is elliptical with one of the foci at the plasma source and the other at the ringfield radius. Each of the 50 degree mirror segments images the source into a 50 degree segment of the ring image. FIG. 5 shows both a meridian cross-sectional view and an isometric view of the beam from one segment 20 of the aspheric mirror, with the isometric view rotated relative to the side view about a line 25 passing through the area of the beam having a smallest beam cross section. It shows the shape of the collector mirror 20, the arc image 22, and the bow-tie-shaped minimum beam cross-section 24, which is located at the center of the axial line focus. This design gives uniform illumination along the length of the arc 22. The lithography system preferably employs a small, compact source of radiation which generates a continuous spectrum of radiation including, for example, EUV, ultraviolet rays, and visible light. An example of such a source is a laser-generated plasma. “Small” implies a radiating volume with dimensions in the three principle directions smaller than about 0.2 mm. “Compact” implies that the three dimensions are roughly the same, differing from one-another by less than a factor of two. These lengths are defined as the full width between the half-maximum intensity points. For EUV lithography, the illumination radiation preferably has a wavelength from about 9 nm to 18 nm and preferably about 13.4 nm. Suitable sources of radiation are the laser plasma source (LPS) which is described, for example, in U.S. Pat. No. 5,577,092 to Kubiak et al. and capillary discharge sources and pulsed capillary discharge sources described in U.S. Pat. Nos. 5,499,282 and 6,031,241 both to Silfvast. Another source is an electric capillary discharge described in U.S. Pat. No. 6,356,618 to Fomaciari et al. As is apparent, the erosion rate of the collection C, mirrors will depend, in significant part, in the design of the radiation source 22 and its proximity to the collection mirrors as illustrated in FIG. 2A. In the case of a laser-generated plasma source, it has been found that the erosion rate of the C1 mirrors is significantly influenced by the laser-to-nozzle separation. The nozzle (or target) is the outlet of the gas supply. Typically, a higher EUV output is realized with decreasing laser-to-nozzle separation, however, the concomitant effect is an increase in the erosion rates on the C1 mirrors. Estimates show that C1 mirrors designed with an underlying reflective surface comprising 40 bilayers of Mo/Si and a sacrificial reflective surface comprising 100 bilayers when used in the photolithography system described above will increase the C1 lifetime by about 175 production days or more. This estimate is based on the production of 10 wafers per day, each having a 4×5 FEM of full-field dies, and each die requiring 80 seconds (0.5 mm/s scan speed) to expose. Proper design should enable the use of a smaller laser-to-target separation for the laser produced plasma, thereby increasing throughput with extended lifetime of C1. When employing C1 mirrors with the sacrificial reflective surface as part of the condenser described above, in order to maximize performance of the photolithography system, the erosion pattern C1 mirrors should also be taken into account. For example, since the erosion is likely to be non-uniform across each of the six C1 mirrors, the reflectance will be spatially varying. In the above described photolithography system, for example, radial reflectance variations on C1 do not appear in the reticle illumination, which is an image of the source in the scan direction. In the non-scan direction a shadow of the six C1 mirrors, that comprise the C1 element, is cast onto the reticle. Azimuthal variation in reflectivity will appear at the reticle. However, the six overlapping channels will likely reduce this variation. Therefore, the condenser is well suited for using collection mirrors with sacrificial reflective surface. The condenser design can compensate for this factor by assuring that the C1 optic not imaged onto the reticle. In principle, condensers can be designed to accommodate spatial and temporal variations in the reflectance of the C1 optic. Ideally, the C1 optic is imaged into the pupil plane, where substantial intensity variations can be tolerated without measurable effect on imaging performance. A related issue that needs to be considered is that magnitude of the reflectance variations of the sacrificial reflective surface as the surface erodes. The variations will depend, in part, on the particular materials used for the bilayers. FIGS. 6A and 6B depict the calculated relationship between the reflectance of C1 mirrors vs. the number of layers remaining on mirrors that initially had 80 total bilayer pairs, i.e., 160 alternating layers of Mo and Si. This represented 40 Mo/Si bilayers for the underlying reflective surface and 40 Mo/Si bilayers for the sacrificial reflective surface. The graphs show the calculated reflectance for the Mo/Si multilayers as the top layers are eroded. In addition, local oscillations which are evident in FIG. 6A are due to the alternating Mo and Si layers. The maximum variation calculated is 1.79% which may be too large to be tolerated at the mask plane, but this can easily be accommodated as an intensity variation at the pupil plane. Non-uniform multilayer erosion will also create figure changes in the surface of the C1 mirrors. (Figure changes refer to deviations from the ideal prescribed shape of an optic). To first order, the removal of multilayers is not expected to change the phase of the reflected wavefront because the reflection is generated from within the depth of the multilayer stack comprised of materials with near unity refractive index. However, when a large number of mulitlayers are removed the second order effects will result in a measurable phase error in the reflected wavefront. If the multilayer stresses are high, relaxation, due to erosion of top layers, will induce figure changes. One or both of these effects may limit the number of sacrificial multilayers that can be used. Since the figure requirements for the condenser are much looser than those for the imaging optics, this consideration should not be a major constraint. In the extreme case that the photolithography system is shut down and the C, mirrors, with the sacrificial reflective surface, has a Mo layer at the top surface, oxidation over an extended period of time will yield a thick layer of MoO2. If the Mo layer is 2.76 nm thick, and assuming a volume increase by 2×, 5.5 nm thick MoO2 can be formed. This phenomenon results in a reflectivity loss of 15.6%. If the all six segment surfaces of the C1 mirrors are at this worse case condition, the loss in reflectivity would be evident as a throughput loss. The oxide layer would be removed with further operation of the source of radiation, so that this oxide component of throughput loss will be temporary. Since the change in throughput is small and slowly varying, it should be easily accommodated in normal tool operation. Although only preferred embodiments of the invention are specifically disclosed and described above, it will be appreciated that many modifications and variations of the present invention are possible in light of the above teachings and within the purview of the appended claims without departing from the spirit and intended scope of the invention | <SOH> BACKGROUND OF THE INVENTION <EOH>In general, lithography refers to processes for pattern transfer between various media. A lithographic coating is generally a radiation-sensitized coating suitable for receiving a cast image of the subject pattern. Once the image is cast, it is indelibly formed on the coating. The recorded image may be either a negative or a positive of the subject pattern. Typically, a “transparency” of the subject pattern is made having areas which are selectively transparent or opaque to the impinging radiation. Exposure of the coating through the transparency placed in close longitudinal proximity to the coating causes the exposed area of the coating to become selectively crosslinked and consequently either more or less soluble (depending on the coating) in a particular solvent developer. The more soluble, i.e., uncrosslinked, areas are removed in the developing process to leave the pattern image in the coating as less soluble crosslinked polymer. Projection lithography is a powerful and essential tool for microelectronics processing and has supplanted proximity printing. “Long” or “soft” x-rays (a.k.a. Extreme UV) (wavelength rate of 10 to 20 nm) are now at the forefront of research in efforts to achieve smaller transferred feature sizes. With projection photolithography, a reticle (or mask) is imaged through a reduction-projection (demagnifying) lens onto a wafer. Reticles for EUV projection lithography typically comprise a glass substrate coated with an EUV absorbing material covering portions of the reflective surface. In operation, EUV radiation from the illumination system (condenser) is projected toward the surface of the reticle and radiation is reflected from those areas of the reticle reflective surface which are exposed, i.e., not covered by the EUV absorbing material. The reflected radiation is re-imaged to the wafer using a reflective optical system and the pattern from the reticle is effectively transcribed to the wafer. A source of EUV radiation is the laser-produced plasma EUV source, which depends upon a high power, pulsed laser (e.g., a yttrium aluminum garnet (“YAG”) laser, or an excimer laser, delivering 500 to 1,000 watts of power to a 50 μm to 250 μm spot, thereby heating a source material to, for example 250,000° C., to emit EUV radiation from the resulting plasma. Plasma sources are compact, and may be dedicated to a single production line so that malfunction does not close down the entire plant. A stepper employing a laser-produced plasma source is relatively inexpensive and could be housed in existing facilities. It is expected that EUV sources suitable for photolithography that provide bright, incoherent EUV and that employ physics quite different from that of the laser-produced plasma source will be developed. One such source under development is the EUV discharge source. EUV lithography machines for producing integrated circuit components are described, for example, in U.S. Pat. No. 6,031,598 to Tichenor et al. Referring to FIG. 7 , the EUV lithography machine comprises a main vacuum or projection chamber 102 and a source vacuum chamber 104 . Source chamber 104 is connected to main chamber 102 through an airlock valve (not shown) which permits either chamber to be accessed without venting or contaminating the environment of the other chamber. Typically, a laser beam 130 is directed by turning mirror 132 into the source chamber 104 . A high density gas, such as xenon, is injected into the plasma generator 136 through gas supply 134 and the interaction of the laser beam 130 , and gas supply 134 creates a plasma giving off the illumination used in EUV lithography. The EUV radiation is collected by segmented collector 138 , that collects about 30% of the available EUV light, and the radiation 140 is directed toward the pupil optics 142 . The pupil optics consists of long narrow mirrors arranged to focus the rays from the collector at grazing angels onto an imaging mirror 143 that redirects the illumination beam through filter/window 144 . Filter 144 passes only the desired EUV wavelengths and excludes scattered laser beam light in chamber 104 . The illumination beam 145 is then reflected from the relay optics 146 , another grazing angel mirror, and then illuminates the pattern on the reticle 148 . Mirrors 138 , 142 , 143 , and 146 together comprise the complete illumination system or condenser. The reflected pattern from the reticle 148 then passes through the projection optics 150 which reduces the image size to that desired for printing on the wafer. After exiting the projection optics 150 , the beam passes through vacuum window 152 . The beam then prints its pattern on wafer 154 . Debris generated by the plasma source is one of the most significant impediments to the successful development of photolithography. In particular, debris tends to erode the optics used to collect the EUV light which severely degrades their EUV reflectance. Ultimately, the erosion will reduce the optics' efficiency to a point where they must be replaced frequently. The art is in search of techniques that address this problem. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention is based in part on the recognition that employing collector optics that have a sacrificial reflective surface can significantly enhance the useful life of the collector optics and subsequently improve the overall performance of the condenser in which the collector optics are incorporated. In one embodiment, the invention is directed to a condenser system for use with a camera to collect and image radiation to a mask the includes: a source of radiation; and at least one collector mirror facing the source of radiation wherein the at least one collector mirror comprises a substrate, an underlying reflective surface, and an upper sacrificial reflective surface. In another embodiment, the invention is directed to a condenser system having a set of mirrors for collecting extreme ultra-violet (EUV) radiation from a radiation source that forms a source image correcting mirrors which are capable of translating or rotating, or both, one or more beams from said set of mirrors and are capable of modifying the convergence of the one or more beams or the size of the source image, or both, and wherein the system includes at least one collector mirror facing a source of EUV radiation wherein the at least one collector mirror comprises a substrate, an underlying reflective surface, and an upper sacrificial reflective surface. In a further embodiment, the invention is directed to a method of preparing a collector mirror of a condenser system for collecting radiation of a selected wavelength from a source of radiation that includes the steps of: (a) depositing a first multilayer film on a substrate such that the film achieves a desired reflectance with respect to a first radiation light having a first wavelength; and (b) depositing a second multilayer film on the first multilayer film, wherein the second multiplayer film also reflects the first radiation light. | 20040116 | 20060725 | 20050721 | 80229.0 | 0 | AMARI, ALESSANDRO V | CONDENSER OPTIC WITH SACRIFICIAL REFLECTIVE SURFACE | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,760,122 | ACCEPTED | System and method for processing and presenting arrhythmia information to facilitate heart arrhythmia identification and treatment | A system and method for presenting information relating to heart data can involve operations including identifying arrhythmia events in physiological data obtained for a living being, receiving human assessments of at least a portion of the arrhythmia events, determining a measure of correlation between the human assessments and the identified events, and selectively presenting information regarding the identified events based on the measure of correlation. The operations can also include identifying atrial fibrillation events in physiological data obtained for a living being, obtaining heart rate data for the living being, and presenting information regarding the heart rate data and duration of the atrial fibrillation events together with a common time scale to pictographically represent heart rate trend with atrial fibrillation burden during a defined time period. | 1. A machine-implemented method comprising: identifying atrial fibrillation events in physiological data obtained for a living being; obtaining heart rate data for the living being; and pictographically presenting, using a common time scale, information regarding the heart rate data during a defined time period and regarding duration of atrial fibrillation activity, according to the identified atrial fibrillation events, during the defined time period such that heart rate trend is presented with atrial fibrillation burden. 2. The method of claim 1, wherein pictographically presenting information comprises presenting information regarding both incidence and duration of identified atrial fibrillation events during the defined time period. 3. The method of claim 1, wherein the heart rate data comprise information presented in beats-per-minute. 4. The method of claim 3, wherein the heart rate data comprise information presented in average beats-per-minute and comprises information regarding standard deviation of heart rate. 5. The method of claim 1, wherein pictographically presenting information comprises presenting heart rate trend juxtaposed with atrial fibrillation burden. 6. The method of claim 1, wherein pictographically presenting information comprises presenting heart rate trend and atrial fibrillation burden on the same graph. 7. The method of claim 1, wherein pictographically presenting information comprises presenting heart rate trend and atrial fibrillation burden on different graphs. 8. The method of claim 1, wherein identifying atrial fibrillation events comprises examining the physiological data in time intervals, and identifying the intervals in which at least one atrial fibrillation event has occurred, and wherein presenting information comprises displaying the identified intervals in alignment with the information regarding the heart rate data on the common time scale. 9. The method of claim 1, wherein presenting information comprises selectively presenting the information based on a measure of correlation between the identified atrial fibrillation events and human-assessments of at least a portion of the identified atrial fibrillation events. 10. The method of claim 1, further comprising receiving input specifying the defined time period. 11. A machine-implemented method comprising: identifying arrhythmia events in physiological data obtained for a living being, the identified arrhythmia events representing a first group of data; receiving a second group of data that includes human assessments of at least a portion of the arrhythmia events; determining at least one measure of correlation between the first group of data and the second group of data; and if the measure of correlation matches or exceeds at least one predetermined value, selectively presenting, based on this measure of correlation, information regarding at least a portion of the arrhythmia events. 12. The method of claim 11, wherein identifying arrhythmia events comprises identifying atrial fibrillation events, and selectively presenting information comprises presenting information regarding the atrial fibrillation events and heart rate data for the living being, during a defined time period, together with a common time scale if the measure of correlation indicates a high positive predictivity for the identification of atrial fibrillation events during the defined time period. 13. The method of claim 12, wherein receiving human assessments comprises receiving human assessments of a subset of the atrial fibrillation events, and identifying atrial fibrillation events comprises: examining the physiological data in time intervals, identifying the intervals in which at least one atrial fibrillation event has occurred, and reporting the identified intervals. 14. The method of claim 13, wherein presenting the information comprises displaying the identified intervals in alignment with the information regarding the heart rate data on the common time scale. 15. The method of claim 13, further comprising identifying a subset of the atrial fibrillation events that are urgent or representative, the identified subset being the human assessed subset. 16. The method of claim 13, wherein determining a measure of correlation between the human assessments and the identified events comprises: assessing, based on comparing at least time data, a number of the identified intervals that encompass at least a portion of human-assessed arrhythmia events. 17. The method of claim 13, wherein presenting the information regarding the heart rate data comprises displaying a heart rate trend graph including maximum heart rates in time intervals. 18. The method of claim 17, wherein each of the heart rate intervals is thirty minutes, and each of the atrial fibrillation intervals is ten minutes. 19. The method of claim 12, wherein presenting the information comprises displaying the information in two graphs using the common time scale. 20. The method of claim 12, wherein presenting the information comprises displaying the information in a single graph using the common time scale. 21. An article comprising a machine-readable medium embodying information indicative of instructions that when performed by one or more machines result in operations comprising: identifying atrial fibrillation events in physiological data obtained for a living being; obtaining heart rate data for the living being; and pictographically presenting, using a common time scale, information regarding the heart rate data during a defined time period and regarding duration of atrial fibrillation activity, according to the identified atrial fibrillation events, during the defined time period such that heart rate trend is presented with atrial fibrillation burden. 22. The article of claim 21, wherein identifying atrial fibrillation events comprises examining the physiological data in time intervals, and identifying the intervals in which at least one atrial fibrillation event has occurred, and wherein presenting information comprises displaying the identified intervals in alignment with the information regarding the heart rate data on the common time scale. 23. The article of claim 21, wherein presenting information comprises selectively presenting the information based on a measure of correlation between the identified atrial fibrillation events and human-assessments of at least a portion of the identified atrial fibrillation events. 24. An article comprising a machine-readable medium embodying information indicative of instructions that when performed by one or more machines result in operations comprising: identifying arrhythmia events in physiological data obtained for a living being, the identified arrhythmia events representing a first group of data; receiving a second group of data that includes human assessments of at least a portion of the arrhythmia events; determining at least one measure of correlation between the first group of data and the second group of data; and if the measure of correlation matches or exceeds at least one predetermined value, selectively presenting, based on this measure of correlation, information regarding at least a portion of the arrhythmia events. 25. The article of claim 24, wherein identifying arrhythmia events comprises identifying atrial fibrillation events, and selectively presenting information comprises presenting information regarding the atrial fibrillation events and heart rate data for the living being, during a defined time period, together with a common time scale if the measure of correlation indicates a high positive predictivity for the identification of atrial fibrillation events during the defined time period. 26. The article of claim 25, wherein receiving human assessments comprises receiving human assessments of a subset of the atrial fibrillation events, and identifying atrial fibrillation events comprises: examining the physiological data in time intervals, identifying the intervals in which at least one atrial fibrillation event has occurred, and reporting the identified intervals. 27. A machine-implemented method comprising: identifying arrhythmia events in physiological data obtained for a living being, the identified arrhythmia events representing a first group of data; receiving a second group of data that includes human assessments of at least a portion of the arrhythmia events; determining at least one measure of correlation between the first group of data and the second group of data; and if the measure of correlation matches or is less than at least one predetermined value, selectively presenting, based on this measure of correlation, information regarding at least a portion of the arrhythmia events. 28. The method of claim 27, wherein identifying arrhythmia events comprises identifying atrial fibrillation events and selectively presenting information comprises presenting information regarding the atrial fibrillation events and heart rate data for the living being, during a defined time period, together with a common time scale if the measure of correlation indicates a high positive predictivity for the identification of atrial fibrillation events during the defined time period. 29. An article comprising a machine-readable medium embodying information indicative of instructions that when performed by one or more machines result in operations comprising: identifying arrhythmia events in physiological data obtained for a living being, the identified arrhythmia events representing a first group of data; receiving a second group of data that includes human assessments of at least a portion of the arrhythmia events; determining at least one measure of correlation between the first group of data and the second group of data; if the measure of correlation matches or is less than at least one predetermined value, selectively presenting, based on this measure of correlation, information regarding at least a portion of the arrhythmia events. 30. The article of claim 29, wherein identifying arrhythmia events comprises identifying atrial fibrillation events and selectively presenting information comprises presenting information regarding the atrial fibrillation events and heart rate data for the living being, during a defined time period, together with a common time scale if the measure of correlation indicates a high positive predictivity for the identification of atrial fibrillation events during the defined time period. 31. A system for reporting information related to arrhythmia events comprising: a monitoring system configured to process and report physiological data for a living being and configured to identify arrhythmia events from the physiological data; a monitoring station for receiving the physiological data from the monitoring system; a processing system configured to receive arrhythmia information from the monitoring system and configured to receive human-assessed arrhythmia information from the monitoring station wherein the human-assessed arrhythmia information derives from at least a portion of the physiological data and wherein the processing system reports information regarding arrhythmia events if a correlation measure relating to a correlation between the arrhythmia information from the monitoring system and the human-assessed arrhythmia information matches or exceeds a predetermined value. 32. The system of claim 31, wherein the processing system is capable of presenting information regarding atrial fibrillation events and heart rate data for the living being, during a defined time period, together with a common time scale if the correlation measure indicates a high positive predictivity for the identification of atrial fibrillation events during the defined time period. 33. A system for reporting information related to arrhythmia events comprising: a monitoring system configured to process and report physiological data, including heart rate data, for a living being and configured to identify arrhythmia events from the physiological data; a monitoring station for receiving the physiological data from the monitoring system; a processing system configured to receive arrhythmia information from the monitoring system and configured to receive human-assessed arrhythmia information from the monitoring station wherein the human-assessed arrhythmia information derives from at least a portion of the physiological data and wherein the processing system is capable of pictographically presenting, using a common time scale, information regarding the heart rate data during a defined time period and regarding duration of arrhythmia event activity, according to the identified arrhythmia events, during the defined time period such that heart rate trend is presented with arrhythmia event burden. 34. The system of claim 33 wherein the monitoring system is capable of examining the physiological data in time intervals and identifying the intervals in which at least one atrial fibrillation event has occurred and wherein the processing system is capable of displaying the identified intervals in alignment with the information regarding the heart rate data on the common time scale. 35. A system for reporting information related to arrhythmia events comprising: monitoring means for processing and reporting physiological data, including heart rate data, for a living being and for identifying arrhythmia events from the physiological data; display means for receiving the physiological data from the monitoring means and for displaying the physiological data to a human user; processing means for receiving arrhythmia information from the monitoring system and for receiving human-assessed arrhythmia information from the display means wherein the human-assessed arrhythmia information derives from at least a portion of the physiological data and wherein the processing means is capable of pictographically presenting, using a common time scale, information regarding the heart rate data during a defined time period and regarding duration of arrhythmia event activity, according to the identified arrhythmia events, during the defined time period such that heart rate trend is presented with arrhythmia event burden. 36. The system of claim 35 wherein the monitoring means is capable of examining the physiological data in time intervals and identifying the intervals in which at least one atrial fibrillation event has occurred and wherein the processing means is capable of displaying the identified intervals in alignment with the information regarding the heart rate data on the common time scale. 37. A machine implemented method comprising: obtaining heart rate data for a living being; identifying atrial fibrillation events in physiological data obtained for the living being, the identified atrial fibrillation events representing a first group of data, and wherein identifying atrial fibrillation events includes examining the physiological data in time intervals and identifying the intervals in which at least one atrial fibrillation event has occurred; receiving a second group of data that includes human assessments of at least a portion of the atrial fibrillation events; determining at least one measure of correlation between the first group of data and the second group of data, wherein determining at least one measure of correlation includes assessing, based on comparing at least time data, a number of the identified intervals that encompass at least a portion of the human-assessed atrial fibrillation events; if the measure of correlation matches or exceeds at least one predetermined value, pictographically presenting, using a common time scale, information regarding the heart rate data during a defined time period and regarding duration of atrial fibrillation activity, according to the identified atrial fibrillation events, during the defined time period such that heart rate trend is juxtaposed with atrial fibrillation burden and wherein pictographically presenting includes displaying the identified intervals in alignment with the information regarding the heart rate data on the common time scale. 38. The method of claim 37, wherein pictographically presenting comprises presenting information regarding the atrial fibrillation events and heart rate data for the living being, during a defined time period, together with a common time scale if the measure of correlation indicates a high positive predictivity for the identification of atrial fibrillation events during the defined time period. 39. An apparatus comprising: means for identifying atrial fibrillation events in physiological data obtained for a living being; means for obtaining heart rate data for the living being; and means for pictographically presenting, using a common time scale, information regarding the heart rate data during a defined time period and regarding duration of atrial fibrillation activity, according to the identified atrial fibrillation events, during the defined time period such that heart rate trend is presented with atrial fibrillation burden. 40. The apparatus of claim 39, wherein the means for pictographically presenting is capable of presenting information regarding the atrial fibrillation events and heart rate data for the living being, during a defined time period, together with a common time scale if the measure of correlation indicates a high positive predictivity for the identification of atrial fibrillation events during the defined time period. 41. An apparatus comprising: means for identifying arrhythmia events in physiological data obtained for a living being, the identified arrhythmia events representing a first group of data; means for receiving a second group of data that includes human assessments of at least a portion of the arrhythmia events; means for determining at least one measure of correlation between the first group of data and the second group of data; means for selectively presenting, based on this measure of correlation, information regarding at least a portion of the arrhythmia events if the measure of correlation matches or exceeds at least one predetermined value. 42. The apparatus of claim 41, wherein the arrhythmia events comprise atrial fibrillation events and wherein the means for selectively presenting is capable of presenting information regarding the atrial fibrillation events and heart rate data for the living being, during a defined time period, together with a common time scale if the measure of correlation indicates a high positive predictivity for the identification of atrial fibrillation events during the defined time period. 43. A machine implemented method comprising: obtaining heart rate data for a living being; identifying arrhythmia events in physiological data obtained for the living being, the identified arrhythmia events representing a first group of data, and wherein identifying arrhythmia events includes examining the physiological data in time intervals and identifying the intervals in which at least one arrhythmia events event has occurred; receiving a second group of data that includes human assessments of at least a portion of the arrhythmia events; determining at least one measure of correlation between the first group of data and the second group of data, wherein determining at least one measure of correlation includes assessing, based on comparing at least time data, a number of the identified intervals that encompass at least a portion of the human-assessed arrhythmia events; if the measure of correlation matches or exceeds at least one predetermined value, pictographically presenting, using a common time scale, information regarding the heart rate data during a defined time period and regarding duration of arrhythmia events activity, according to the identified arrhythmia events, during the defined time period such that heart rate trend is juxtaposed with arrhythmia event burden and wherein pictographically presenting includes displaying the identified intervals in alignment with the information regarding the heart rate data on the common time scale. 44. The method of claim 43, wherein pictographically presenting comprises presenting information regarding the arrhythmia events and heart rate data for the living being, during a defined time period, together with a common time scale if the measure of correlation indicates a high positive predictivity for the identification of arrhythmia events during the defined time period. 45. A machine-implemented method comprising: identifying arrhythmia events in physiological data obtained for a living being, the identified arrhythmia events representing a first group of data; receiving a second group of data that includes human assessments of at least a portion of the arrhythmia events; determining at least one measure of correlation between the first group of data and the second group of data; and if the measure of correlation matches or exceeds at least one predetermined value, selectively presenting, based on this measure of correlation, information regarding at least a portion of the identified arrhythmia events and wherein selectively presenting information comprises presenting information regarding the identified arrhythmia events and heart rate data for the living being, during a defined time period, together with a common time scale if the measure of correlation indicates a high positive predictivity for the identification of arrhythmia events during the defined time period. 46. The method of claim 45, wherein receiving human assessments comprises receiving human assessments of a subset of the identified arrhythmia events, and identifying arrhythmia events comprises: examining the physiological data in time intervals, identifying the intervals in which at least one identified arrhythmia event has occurred, and reporting the identified intervals. | CROSS REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority from U.S. Provisional Application entitled “Presenting Arrhythmia Information to Facilitate Heart Arrhythmia Identification and Treatment,” filed Nov. 26, 2003, application Ser. No. 60/525,386. BACKGROUND The present application describes systems and techniques relating to processing and presenting arrhythmia event information from physiological data, for example, selectively presenting atrial fibrillation events to a medical practitioner. Over the years, various devices have been used for monitoring hearts in living beings. Additionally, systems have been used to collect and report on heart information obtained from patients. SUMMARY In general, in one aspect, a heart monitoring system collects heart data from a monitored individual and stores the data at a monitoring center. Collected data can be processed, and graphical representations of the collected information can be presented to medical practitioners to assist in treating heart arrhythmias, such as atrial fibrillation. A system and method can involve operations including identifying arrhythmia events in physiological data obtained for a living being, receiving human assessments of at least a portion of the arrhythmia events, determining a measure of correlation between the human assessments and the identified events, and selectively presenting information regarding the identified events based on the measure of correlation. The operations also can include identifying atrial fibrillation events in physiological data obtained for a living being, obtaining heart rate data for the living being, and presenting information regarding the heart rate data and duration of the atrial fibrillation events together with a common time scale to pictographically represent heart rate trend with atrial fibrillation burden during a defined time period. One or more of the following advantages can be realized. The heart monitor can loop every twenty-four hours and can automatically transmit heart data at least every twenty-four hours. The system can automatically generate a daily graphical summary of atrial fibrillation (AF) burden for review by a medical practitioner, which can be presented effectively anywhere using one or more communication networks. The AF burden graph can be used for asymptomatic AF detection, drug therapy (rate, rhythm, anti-coagulants), pre/post ablation monitoring, and CHF (congestive heart failure) decompensation. The system can provide an overall sensitivity of 96%, a positive predictivity of over 99%, and artifact rejection of over 90%. In one implementation, the graph only displays events where AF detection is validated by a technician finding AF in over 50% of the automatically identified events. The details of one or more embodiments 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. DRAWING DESCRIPTIONS FIG. 1 illustrates, according to an exemplary embodiment, a system for reporting information related to arrhythmia events. FIG. 2 shows, according to one embodiment, a graph presenting an example of atrial fibrillation burden and heart rate trend. FIG. 3 is a diagram illustrating, according to an exemplary embodiment, a procedure for monitoring, processing, and reporting information related to arrhythmia events. FIG. 4 shows, according to an exemplary embodiment, one graph presenting an example of atrial fibrillation burden and one graph presenting an example of heart rate trend. FIGS. 5 and 6 are diagrams illustrating, according to another exemplary embodiment, a procedure for monitoring, processing, and reporting information related to arrhythmia events. DETAILED DESCRIPTION FIG. 1 illustrates, according to one embodiment, a system for reporting information related to arrhythmia events, such as atrial fibrillation events. In this embodiment, monitoring system 109 can communicate (via devices 101 and 102) ECG (electrocardiogram), cardiac event, and other data to monitoring center 104. The system 109 can include, for example, an implantable medical device (IMD), such as an implantable cardiac defibrillator and an associated transceiver or pacemaker and an associated transceiver, or a monitoring device 101 that a patient 110 wears. Further, monitoring system 109 can include a monitor processing device 102 that can send standard physiological data (received from monitoring device 101) to monitoring center 104 and that can detect arrhythmia events (such as atrial fibrillation events). In one implementation, the devices 101 and 102 are integrated into a single device. Moreover, the system 109 can be implemented using, for example, the CardioNet Mobile Cardiac Outpatient Telemetry (MCOT) device, which is commercially available and provided by CardioNet, Inc of San Diego, Calif. Monitor processing device 102 can transmit physiological data (including data related to arrhythmia events) through a communication network 103, which can be a local area network (LAN), a landline telephone network, a wireless network, a satellite communication network, or other suitable network to facilitate two-way communication with monitoring center 104. Advantageously, monitoring center 104 can be located in the same location (e.g., in the same room or building) as monitoring system 109 or at some remote location. The monitoring center 104 can include a monitoring (or display) station 105 and a processing system 106. In one implementation, a cardiovascular technician (CVT) can use the monitoring station 105 to evaluate physiological data received from monitoring system 109, identifying and reporting, among other things, arrhythmia events (such as atrial fibrillation events). The CVT reports these assessments of the physiological data to the processing system 106, which also receives information related to the arrhythmia events identified by monitoring system 109. As will be explained further below, processing system 106 analyzes this arrhythmia event data (both the human-assessed data from the CVT and the data reported by monitoring system 109) and determines whether to generate a graph (or other similar presentation) related to these events. In certain circumstances, the processing system will send a report related to both arrhythmia and heart rate data to, for example, a physician or other health care provider 108 via transmission path 107—which may be part of the network 103. FIG. 3 illustrates, according to one embodiment, a procedure for monitoring, processing, and reporting arrhythmia event data (such as data associated with atrial fibrillation events). In this embodiment, the monitoring system 109 (illustrated in FIG. 1) monitors and reports physiological data (including data related to heart rate) at 301. At 302, various parts of this physiological data can be analyzed (for example, RR variability and QRS morphology) and arrhythmia events can be identified based on predefined criteria—the information relating to these events (among other possible information) constituting a first group of data. In one implementation, the monitoring system 109 identifies certain of the arrhythmia events that are urgent or representative and reports those events to both a CVT at 303 and to the processing system at 304. Alternatively, the system could simply report the events identified at 302 to the processing system. Further, at 303, a CVT, using station 105, evaluates various parts of the physiological data received from 302 and/or 301 and also identifies arrhythmia events—the information relating to these human-assessed events (among other possible information) constituting a second group of data. Here, if needed, the CVT can request additional data from monitoring system 109. At 304, the processing system 106 analyzes both the first and second group of data, determining a measure of correlation between these groups. This process can involve, for example, determining whether a correlation measure exceeds and/or equals a predetermined correlation parameter or whether a correlation measure is less than and/or equals that parameter. If, based on the correlation analysis, the information related to the arrhythmia events is determined to be valid, then the system generates a report relating to both heart rate trend and the arrhythmia events at 305, such as the graph shown in FIG. 2 or the graphs shown in FIG. 4. If, on the other hand, there is insufficient correlation, then the system does not generate a report and monitoring continues. To illustrate, in one implementation, every ten minutes, the monitoring system 109 transmits a “flag” if it has detected an atrial fibrillation (AF) event in the last ten minutes. In this implementation, the processing system 106 only generates a graph (or graphs) related to heart rate trend and atrial fibrillation burden—such as the graph shown in FIG. 2 or the graphs shown in FIG. 4—if more than 50% of the ten minute flags (generated at 302) match events identified by a CVT (at 303)—a correlation (with respect to the time period at issue) indicating a high positive predictivity for the identification of AF events. If this 50% threshold is not met, then the system does not generate a graph (or graphs) based on the data at issue and simply continues to process data. The term “atrial fibrillation burden” (or more generally, “arrhythmia event burden”) refers generally to the overall amount of time that a patient is in atrial fibrillation (or arrhythmia) over a specified time period, taking into account the number and duration of episodes. Advantageously, employing pictographic presentations, such as those of FIGS. 2 and 4, a medical practitioner can see whether a patient is more likely to experience an arrhythmia, such as AF, at certain times of the day, and this can affect therapeutic approaches in some cases. FIG. 2 represents one example of how to pictographically present both heart rate trend and atrial fibrillation burden on a common time scale (to “pictographically present” such data, however, a graph is not required.). The graph 205 contains information relating to, for example, daily AF incidence and time of occurrence 201, AF duration 202, and heart rate (203 and 204). A scale 204 (in this example) indicates heart rate in average beats-per-minute and the dots and lines shown at 203 (for example) indicate values on that scale, standard deviations associated with these values, and heart rates during AF. Further, graph 205 shows heart rate data at 15 minutes and 45 minutes past the hour. Finally, in this graph, the presence of one or more AF events in a given 10-minute period is graphed as a 10-minute interval. Like FIG. 2, FIG. 4 represents an example of how to pictographically present heart rate trend and atrial fibrillation burden on a common time scale. Although FIG. 4, unlike FIG. 2, uses two graphs, FIG. 4 presents the same information as FIG. 2. Specifically, graphs 404 and 405 contain information relating to, for example, daily AF incidence and time of occurrence 401, AF duration 402, and heart rate (403 and 406). A scale 406 (in this example) indicates heart rate in average beats-per-minute and the dots and lines shown at 403 (for example) indicate values on that scale, standard deviations associated with these values, and heart rates during AF. FIGS. 5 and 6 are diagrams illustrating another implementation of the invention. Specifically, at 501, the system 111, employing monitoring system 109, obtains physiological data, including heart rate data. In turn, at 502, the system identifies the presence of arrhythmia events (such as AF events) in this physiological data, examining this data in time intervals. At 503, the system assigns flags indicating the presence of arrhythmia events and reports those flags—which represent a first group of data—to the processing system. Similarly, at 504, the system identifies and reports physiological data, such as ECG data, for a subset of the events identified at 502 and reported at 503. Notably, the system, in this implementation, need not report physiological data for each flag assigned at 503, but need only report data associated with the most significant events identified at 502, thereby minimizing the data sent to a CVT. At 601, the CVT analyzes this data and reports whether arrhythmia events have occurred, thereby generating a second group of data. The processing system then determines (at 602), based on comparing time stamps associated with each group of data, at least one measure of correlation between the first group of data and the second group of data. To illustrate, if enough of the human-assessed events reported at 601 match the events reported at 503, then the system determines that the data is valid, that is, that there is a high positive predictivity for the identification of arrhythmia events. If such a determination is made, the data associated with each flag reported at 503 is pictographically presented in a form such as FIG. 2 or FIG. 4. Significantly, in this implementation, while this pictographic representation can contain all such data, the CVT need only review a subset of this data. In short, the system achieves increased accuracy in the presentation of information relating to arrhythmia events while minimizing the data that the CVT reviews. The disclosed system and all of the functional operations described and illustrated in this specification can be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of the forgoing. Apparatus can be implemented in a software product (e.g., a computer program product) tangibly embodied in a machine-readable storage device for execution by a programmable processor, and processing operations can be performed by a programmable processor executing a program of instructions to perform functions by operating on input data and generating output. Further, the system can be implemented advantageously in one or more software programs that are executable on a programmable system. This programmable system can include the following: 1) at least one programmable processor coupled to receive data and instructions from, and to transmit data and instructions to, a data storage system; 2) at least one input device; and 3) at least one output device. Moreover, each software program can be implemented in a high-level procedural or object-oriented programming language, or in assembly or machine language if desired; and in any case, the language can be a compiled or an interpreted language. Also, suitable processors include, by way of example, both general and special purpose microprocessors. Generally, a processor will receive instructions and data from a read-only memory, a random access memory, and/or a machine-readable signal (e.g., a digital signal received through a network connection). Generally, a computer will include one or more mass storage devices for storing data files. Such devices can include magnetic disks, such as internal hard disks and removable disks, magneto-optical disks, and optical disks. Storage devices suitable for tangibly embodying software program instructions and data include all forms of non-volatile memory, including, by way of example, the following: 1) semiconductor memory devices, such as EPROM (electrically programmable read-only memory); EEPROM (electrically erasable programmable read-only memory) and flash memory devices; 2) magnetic disks such as internal hard disks and removable disks; 3) magneto-optical disks; and 4) CD-ROM disks. Any of the foregoing can be supplemented by, or incorporated in, ASICs (application-specific integrated circuits). To provide for interaction with a user (such as the CVT), the system can be implemented on a computer system having a display device such as a monitor or LCD (liquid crystal display) screen for displaying information to the user and a keyboard and a pointing device such as a mouse or a trackball by which the user can provide input to the computer system. The computer system can be programmed to provide a graphical user interface through which computer programs interact with users. Finally, while the foregoing system has been described in terms of particular implementations, other embodiments are within the scope of the following claims. For example, the disclosed operations can be performed in a different order and still achieve desirable results. Moreover, the system need not employ 10-minute intervals; many different time intervals are possible (as is no interval at all), including 1 minute, 30 second, and 30-minute intervals. Indeed, because time intervals are not required, the graphs of FIGS. 2 and 4 could be modified to show continuous heart rate trend (accompanied by corresponding AF data) rather than just specific instances of this trend. Further, while FIGS. 2 and 4 show examples of (among other things) pictographically presenting atrial fibrillation burden (one type of arrhythmia event burden), one could present the same or similar information for another type of arrhythmia event. In fact, one could employ both the format and procedures associated with generating FIG. 2 or FIG. 4 (or a similar figure) to pictographically present information related to a number of different types of arrhythmia event burdens. | <SOH> BACKGROUND <EOH>The present application describes systems and techniques relating to processing and presenting arrhythmia event information from physiological data, for example, selectively presenting atrial fibrillation events to a medical practitioner. Over the years, various devices have been used for monitoring hearts in living beings. Additionally, systems have been used to collect and report on heart information obtained from patients. | <SOH> SUMMARY <EOH>In general, in one aspect, a heart monitoring system collects heart data from a monitored individual and stores the data at a monitoring center. Collected data can be processed, and graphical representations of the collected information can be presented to medical practitioners to assist in treating heart arrhythmias, such as atrial fibrillation. A system and method can involve operations including identifying arrhythmia events in physiological data obtained for a living being, receiving human assessments of at least a portion of the arrhythmia events, determining a measure of correlation between the human assessments and the identified events, and selectively presenting information regarding the identified events based on the measure of correlation. The operations also can include identifying atrial fibrillation events in physiological data obtained for a living being, obtaining heart rate data for the living being, and presenting information regarding the heart rate data and duration of the atrial fibrillation events together with a common time scale to pictographically represent heart rate trend with atrial fibrillation burden during a defined time period. One or more of the following advantages can be realized. The heart monitor can loop every twenty-four hours and can automatically transmit heart data at least every twenty-four hours. The system can automatically generate a daily graphical summary of atrial fibrillation (AF) burden for review by a medical practitioner, which can be presented effectively anywhere using one or more communication networks. The AF burden graph can be used for asymptomatic AF detection, drug therapy (rate, rhythm, anti-coagulants), pre/post ablation monitoring, and CHF (congestive heart failure) decompensation. The system can provide an overall sensitivity of 96%, a positive predictivity of over 99%, and artifact rejection of over 90%. In one implementation, the graph only displays events where AF detection is validated by a technician finding AF in over 50% of the automatically identified events. The details of one or more embodiments 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. | 20040116 | 20070501 | 20050526 | 95380.0 | 3 | GETZOW, SCOTT M | SYSTEM AND METHOD FOR PROCESSING AND PRESENTING ARRHYTHMIA INFORMATION TO FACILITATE HEART ARRHYTHMIA IDENTIFICATION AND TREATMENT | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,760,375 | ACCEPTED | Machine tool | A machine tool has a support table provided on an upper surface of a bed to support a work, a Z-axis saddle, a machining unit mounted on the Z-axis saddle and provided with a machining head, a compartment cover arranged on the bed to compartment a region and a machine region, an opening window provided on the compartment cover to permit the machining head to go in and out therethrough, and a seal member in the form of a closed ring to be mounted on an inner peripheral edge of the opening window of the compartment cover, wherein an entire periphery of an outer peripheral surface of the machining head is brought into sliding contact with an inner peripheral edge of the seal member in a state, in which the machining head is moved into the machining region from a tool exchange position within the machine region. | 1. A machine tool comprising: a support table provided on an upper surface of a bed to support a work; a Z-axis saddle for reciprocation toward in a Z-axis direction (longitudinally); a machining unit mounted on the Z-axis saddle and provided with a machining head for machining of the work; a compartment cover arranged on the bed to compartment a region, in which a work supported on the support table is machined, and a machine region, in which the machining unit is movably arranged; an opening window provided on the compartment cover to permit the machining head to go in and out therethrough; and a seal member in the form of a closed ring to be mounted on an inner peripheral edge of the opening window of the compartment cover; wherein an entire periphery of an outer peripheral surface of the machining head is brought into sliding contact with an inner peripheral edge of the seal member in a state, in which the machining head is moved into the machining region from a tool exchange position within the machine region. 2. A machine tool according to claim 1, wherein the machining unit is configured to permit exchange of plural kinds of machining heads having different body sizes, an opening is formed in the compartment cover to enable a machining head of a maximum size to go in and out, and the opening selectively and exchangeably mounts thereto plural kinds of seal frames comprising amount frame formed with the opening window conformed to a body size of each of the machining heads, and the seal member mounted to an inner peripheral edge of the opening window of the mount frame and put into contact with an outer peripheral surface of a body of the machining head. 3. A machine tool according to claim 1, wherein the machining unit is configured to permit exchange of plural kinds of machining heads having different body sizes, the seal member conformed to a maximum body size of the machining heads is mounted to the opening window of the mount frame, plural kinds of head covers formed into complementary shapes so as to assume the same shape as the external shape of a body of the machining head having the maximum body size upon mounting on those machining heads having sizes, which are equal to or less in size than the maximum body size, are selectively and exchangably mounted on the machining unit, and a seal member is mounted on an inner edge of the head cover to come into contact with the outer peripheral surface of the machining head. 4. A machine tool according to claim 1, wherein the machining head is mounted to be able to reciprocate in a X-axis direction (laterally) or a Y-axis direction (vertically), a shield cover is mounted on the machining unit to shield the machining head and to allow reciprocatory movements of the machining head in the X-axis direction (laterally) or the Y-axis direction (vertically), and an outer peripheral surface of an annular frame constituting the shield cover is brought into sliding contact with an inner peripheral surface of the seal member on a side of the opening window in a state, in which the machining head is moved into the machining region from a tool exchange position within the machine region. 5. A machine tool according to claim 1, wherein the compartment cover comprises an arch-shaped support frame provided upright in a predetermined position on the bed, and an extensible cover mounted inside the support frame to be able to reciprocate together with the seal member in a X-axis direction (laterally) or a Y-axis direction (vertically), and wherein interlocking unit is provided between the machining unit and the extensible cover to move the extensible cover and the seal member in the X-axis direction or the Y-axis direction so that the machining head corresponds to the seal member as viewed in a Z-axis direction when the machining unit is moved in the X-axis direction or the Y-axis direction. 6. A machine tool according to claim 4, wherein the compartment cover comprises a roll cover or a telescopic cover. 7. A machine tool according to claim 5, wherein the compartment cover comprises a roll cover or a telescopic cover. 8. A machine tool according to claim 1, wherein guide rails are mounted immediately on the upper surface of the bed and the Z-axis saddle of the machining unit is mounted on the guide rails. 9. A machine tool according to claim 2, wherein guide rails are mounted immediately on the upper surface of the bed and the Z-axis saddle of the machining unit is mounted on the guide rails. 10. A machine tool according to claim 3, wherein guide rails are mounted immediately on the upper surface of the bed and the Z-axis saddle of the machining unit is mounted on the guide rails. 11. A machine tool according to claim 1, wherein the seal member comprises a scraper having a seal lip and has a tip end thereof directed toward the machining region. 12. A machine tool according to claim 8, wherein the seal member comprises a scraper having a seal lip and has a tip end thereof directed toward the machining region. 13. A machine tool according to claim 9, wherein the seal member comprises a scraper having a seal lip and has a tip end thereof directed toward the machining region. 14. A machine tool according to claim 1, wherein the machining head comprises a multi spindle head provided with a plurality of tools. 15. A machine tool according to claim 11, wherein the machining head comprises a multi spindle head provided with a plurality of tools. | BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a machine tool for advancing and retreating a machining unit from a work supported on a work support table to perform machining of a work, and more particular, to a cover construction. 2. Description of the Related Art Generally, a machine tool comprises a work support table for supporting a work being machined, and a machining unit capable of mounting and dismounting of tools, which perform machining, such as drilling or the like, of the work. The machining unit is composed of a Z-axis saddle mounted on a bet to be able to reciprocate in a Z-axis direction (longitudinally), a column mounted on the Z-axis saddle, and a machining head mounted on the column to grasp tools. And the machining unit is advanced to perform machining of a work, and when machining is terminated, the machining unit is retreated. Also, the column is mounted on the Z-axis saddle to be able to reciprocate in a X-axis direction (laterally). Further, there are some configurations, in which a X-axis saddle for reciprocation relative to the column in a Y-axis direction (vertically) is mounted, the machining head is mounted on the Y-axis saddle, and the machining unit is moved in three axial directions, that is, X-axis direction, Y-axis direction, and Z-axis direction. While the machining head performs machining of a work, coolant containing a cutting oil for cooling and lubrication of tools and a work is supplied. When such coolant and chip enter into a machine region on a side of the machining unit from the machining head, a harmful influence is exerted on various sensors and limit switches provided on the machining unit, or slide members, seal members, or the like on X-axis, Y-axis, and Z-axis drive mechanisms. Therefore, a cover device is provided between the machining unit and a work support table. There has been heretofore proposed as such cover device an arrangement, in which an opening window for taking the machining head in and out in a X-axis direction (longitudinally) is provided on a stationary-side cover for compartment and formation of a machining room of a work, and a movable cover for shielding to prevent scattering of coolant outside from the opening window during machining of a work is provided on an outer peripheral surface of the machining head to be close to an opening window of a compartment cover. A configuration (JP-UM-A-4-115554) similar to the conventional configuration is shown in FIG. 3. Also, a conventional cover device for machine tools is disclosed and proposed in JP-A-6-210531. The cover device is constructed such that a cylindrical-shaped opening of a protective cover surrounding a periphery of a machining head is fitted onto an opening window of a compartment cover in a manner to be able to advance and retreat. Since the conventional cover device, disclosed in JP-UM-A-4-115554, for machine tools is not constructed such that a movable cover is brought into close contact with the opening window of the compartment cover during machining of a work, however, there are caused problems that sealing is made incomplete, and a part of coolant enters into a machine region on a side of the machining unit because the movable cover is opened downward. Further, the cover device cannot cope with the case where a machining unit is of a type, in which tools are driven left and right, and up and down. In recent years, coolant as developed has an adverse influence on equipments such as sensors, limit switches, and so on, and seal members, and so a solution therefor has been demanded. Meanwhile, the cover device, disclosed in JP-A-6-210531, for machine tools is not constructed such that the cylindrical-shaped opening of the protective cover is brought into close contact with the opening window of the compartment cover during machining of a work. Therefore, the machining unit is retreated into a machine region in a state, in which coolant and chip adhere to an outer peripheral surface of the cylindrical-shaped opening, so that the machine region is made dirty. Besides, since an inside of the cylindrical-shaped opening is put in an opened state, coolant, chip, and scraps accumulate therein to be taken into the machine region during retreating of the machining unit while coolant and chip remain adhered to a peripheral surface of the machining head. SUMMARY OF THE INVENTION It is a first object of the invention to dissolve problems involved in the prior art-and to provide a machine tool of a type, in which a machining unit is advanced at the time of machining of a work, and which can prevent coolant and chip from entering a side of the machining unit during machining of a work and can surely prevent coolant and chip from being taken into a machine region due to retreating of the machining unit. In addition to the first object, it is a second object of the invention to provide a machine tool, in which a machining unit can be moved in a transverse direction or in a vertical direction and which comprises a cover construction capable of preventing coolant and chip from entering a side of the machining unit during machining. In order to solve the above problems, according to a first aspect resides in a machine tool comprising a support table provided on an upper surface of a bed to support a work, a Z-axis saddle for reciprocation toward in a Z-axis direction (longitudinally), and a machining unit mounted on the Z-axis saddle and provided with a machining head for machining of the work, and wherein a compartment cover is arranged on the bed to compartment a region, in which a work supported on the support table is machined, and a machine region, in which the machining unit is movably arranged, an opening window is provided on the compartment cover to permit the machining head to go in and out therethrough, a seal member in the form of a closed ring to be mounted on an inner peripheral edge of the opening window of the compartment cover, and an entire periphery of an outer peripheral surface of the machining head is brought into sliding contact with an inner peripheral edge of the seal member in a state, in which the machining head is moved into the machining region from a tool exchange position within the machine region. According to a second aspect resides in that constitution as set forth in the first aspect, in which the machining unit is configured to permit exchange of plural kinds of machining heads having different body sizes, an opening is formed in the compartment cover to enable a machining head of a maximum size to go in and out, and the opening selectively and exchangeably mounts thereto plural kinds of seal frames comprising a mount frame formed with the opening window conformed to a body size of each of the machining heads, and the seal member mounted to an inner peripheral edge of the opening window of the mount frame and put into contact with an outer peripheral surface of a body of the machining head. According to a third aspect resides in that constitution as set forth in the first aspect, in which the machining unit is configured to permit exchange of plural kinds of machining heads having different body sizes, the seal member conformed to a maximum body size of the machining heads is mounted to the opening window of the mount frame, plural kinds of head covers formed into complementary shapes so as to assume the same shape as the external shape of a body of the machining head having the maximum body size upon mounting on those machining heads having sizes, which are equal to or less in size than the maximum body size, are selectively and exchangeably mounted on the machining unit, and a seal member is mounted on an inner edge of the head cover to come into contact with the outer peripheral surface of the machining head. According to a fourth aspect resides in that constitution as set forth in the first aspect, in which the machining head is mounted to be able to reciprocate in a X-axis direction (laterally) or a Y-axis direction (vertically), a shield cover is mounted on the machining unit to shield the machining head and to allow reciprocatory movements of the machining head in the X-axis direction (laterally) or the Y-axis direction (vertically), and an outer peripheral surface of an annular frame constituting the shield cover is brought into sliding contact with an inner peripheral surface of the seal member on a side of the opening window in a state, in which the machining head is moved into the machining region from a tool exchange position within the machine region. According to a fifth aspect resides in that constitution as set forth in the first aspect, in which the compartment cover comprises an arch-shaped support frame provided upright in a predetermined position on the bed, and an extensible cover mounted inside the support frame to be able to reciprocate together with the seal member in a X-axis direction (laterally) or a Y-axis direction (vertically), and wherein interlocking unit is provided between the machining unit and the extensible cover to move the extensible cover and the seal member in the X-axis direction or the Y-axis direction so that the machining head corresponds to the seal member as viewed in a Z-axis direction when the machining unit is moved in the X-axis direction or the Y-axis direction. According to a sixth aspect resides in that constitution as set forth in the fourth or sixth aspect, in which the compartment cover comprises a roll cover or a telescopic cover. According to a seventh aspect resides in that constitution according to any one of the first to sixth aspect, in which guide rails are mounted immediately on the upper surface of the bed and the Z-axis saddle of the machining unit is mounted on the guide rails. According to a eighth aspect resides in that constitution according to any one of the first to seventh aspect, in which the seal member comprises a scraper having a seal lip and has its tip end directed toward the machining region. According to a ninth aspect resides in that constitution according to any one of the first to eighth aspect, in which the machining head comprises a multi spindle head provided with a plurality of tools. ADVANTAGE OF THE INVENTION In the invention as set forth in the first aspect, it is possible in a machine tool of a type, in which a machining unit is advanced in a Z-axis direction at the time of machining of a work, to prevent coolant and chip from entering into a machining region during machining of a work. Also, it is possible to surely prevent coolant and chip from being taken into a machine region due to retreating of the machining unit. In the invention as set forth in the second aspect, when a machining head is to be exchanged by one having a different body size, such exchange can be met by exchange of a seal frame. In the invention as set forth in the third aspect, when a machining head is to be exchanged by one having a different body size, such exchange can be met by exchange of a head cover. In the invention as set forth in the fourth or fifth aspect, it is possible in a machine tool, in which a machining head can be moved in a X-axis direction (laterally) or a Y-axis direction (vertically), to prevent coolant and chip from entering into a side of a machining unit during machining of a work. In the invention as set forth in the sixth aspect, it is possible to simply construct an extensible cover of high air tightness. In the invention as set forth in the seventh aspect, the construction of assembling a machining unit to a bed is made simple to enhance an assembling accuracy and to enhance accuracy, with which tools machine a work. In the invention as set forth in the eighth aspect, a lip seal is used to surely remove coolant or chip adhering to an outer peripheral surface of a body of the head when the machining head is retreated. In the invention as set forth in the ninth aspect, a single machining head can perform plural machining operations at a time, and a seal member can close an entire outer periphery of a head body to surely shield coolant and chip scattered in a machining region. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal, cross sectional view showing a first embodiment of a machine tool according to the invention; FIG. 2 is a longitudinal, cross sectional view showing machining of a work in the machine tool; FIG. 3 is a transverse, cross sectional view showing the machine tool of FIG. 1; FIG. 4 is a longitudinal, cross sectional view showing a machine tool modified in the first embodiment; FIG. 5 is a transverse, cross sectional view showing the modification of FIG. 4; FIG. 6 is a longitudinal, cross sectional view showing a machine tool modified in the first embodiment; FIG. 7 is a front view showing a machining head and a seal frame in FIG. 3; FIG. 8 is a longitudinal, cross sectional view showing a machine tool according to a second embodiment of the invention; FIG. 9 is an enlarged, front view showing a roll cover mechanism in the second embodiment; FIG. 10 is an enlarged longitudinal, cross sectional view showing a roll cover mechanism in the second embodiment; FIG. 11 is a side view showing a machine tool according to a third embodiment of the invention; and FIG. 12 is a front, cross sectional view showing a cover device according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment A first embodiment, in which a cover device for machine tools, according to the invention is embodied, is described below with reference to FIGS. 1 to 3. As shown in FIG. 1, Z-axis guide rails 12 are laid immediately on an upper surface of a bed 11 in a Z-axis direction (front and back), and a Z-axis saddle 13 reciprocated in the Z-axis direction by a Z-axis drive mechanism including a servomotor (not shown) is mounted on the Z-axis guide rails 12. A column 14 is mounted on an upper surface of the Z-axis saddle 13 to be moved in the Z-axis direction. A machining head 15 is mounted on a front surface (left side in FIG. 1) of the column 14 to be directed in the Z-axis direction, and a plurality of drills 16 as tools are mounted on the machining head 15 to constitute a multi spindle head. And the drills 16 are rotatingly driven by a rotary mechanism (not shown) provided in the machining head 15. In this embodiment, a machining unit U is composed of the Z-axis saddle 13, the column 14, the machining head 15, and the drills 16. A work support table 17 is provided on the upper surface of the bed 11 by means of a support shaft, and a work W is held in a predetermined position on an upper surface of the work support table 17 by a clamp mechanism (not shown). Also, formed below the work support table 17 is a chip discharge passage, into which chip and coolant are recovered through a chip drop hole. An arch-shaped (see FIG. 3) support frame 19 is provided upright on the upper surface of the bed 11 to be positioned between the machining unit U and the work support table 17. A compartment cover 20 in the form of a flat plate is mounted on a right side of the support frame 19 by means of bolts or welding. An opening window 20a, through which the machining head 15 can go in and out, is formed centrally of the compartment cover 20. As shown in FIG. 3, the machining head 15 has an external shape of a rectangle being long sideways, as viewed from the Z-axis direction (perpendicular to a plane of the drawing), and the opening window 20a also has an external body shape of a rectangle being long sideways. Mounted on a left side of the compartment cover 20 is a mount frame 21 in the form of a rectangular frame being long sideways, the mount frame being formed with an opening window 21a conformed to the opening window 20a. Joined to a left side of the mount frame 21 by means of an adhesive is a scraper 22 serving as a seal member formed from, for example, synthetic rubber and fluoro rubber, which are favorably corrosion-resistant against coolant. In this embodiment, a seal frame is constituted by the mount frame 21 and the scraper 22, and detachably mounted to the compartment cover 20 by means of a plurality of bolts 23 while being integral. The scraper 22 is formed to assume a shape of a rectangular frame being long sideways as shown in FIG. 3, and a whole shape of a seal lip 22a disposed inside of the scraper, as viewed from the Z-axis direction, is rectangular to be similar to the external body shape of the machining head 15. Respective internal dimensions of length and width of the seal lip 22a are formed to be somewhat smaller than respective external dimensions of length and width of the machining head 15 in a state, in which the seal lip is not in contact with the machining head 15. Tip ends of the seal lip 22a are directed toward a machining region to be able to prevent entry of the coolant into a machine region. An adequate sealing effect is produced even in the case where mist coolant is used. Making use of the support frame 19, a protective cover 24 is provided in a manner to shield the machining unit U. Also, making use of the support frame 19, a protective cover 25 is provided in a manner to shield the work support table 17 and the work W. The protective cover 24 compartments and forms a machine room R1 as a machine region rightwardly of the compartment cover 20 and the protective cover 25 compartments and forms a machining room R2 leftwardly of the compartment cover 20. Subsequently, an operation of the machine tool constituted in the above manner is described. Solid lines in FIG. 6 show a state, in which the machining unit U is moved leftward along the Z-axis guide rails 12, the machining head 15 is disposed in a withdrawal position within the machining room R2, and an outer peripheral edge of a body tip end of the machining head 15 comes into contact with tip end of the seal lip 22a of the scraper 22. In this state, an inner peripheral edge of the seal lip 22a undergoes elastic deformation to be expanded outward. In this state, when the machining unit U is moved forward in the Z-axis direction by a Z-axis drive mechanism (not shown), the machining head 15 of the machining unit U is moved to a machining position within the machining room R2 as shown in FIG. 2 and the work W is subjected to drilling by the plurality of drills 16. When machining of the work is completed, the machining unit U is moved to a withdrawal position shown by solid lines in FIG. 1 from the machining position shown in FIG. 2 within the machining room R2. In addition, in the case where the drills 16 have worn and exchange thereof is necessary, or exchange of the machining head 15 is needed due to modification in machining, the machining unit U is moved to a tool exchange position shown by two-dot chain lines in FIG. 1 within the machine room R1 from the withdrawal position shown by solid lines in FIG. 1 within the machining room R2, and exchange of the drills 16 or exchange of the machining head 15 is effected. According to the embodiment, the following features are provided. (1) In the embodiment, the scraper 22 is mounted corresponding to the opening window 20a of the compartment cover 20, the machining head 15 mounted on the column 14 is caused to enter into the scraper 22 from the opening window 20a, and the seal lip 22a of the scraper 22 seals an entire outer peripheral surface of a body of the machining head 15. Therefore, it is possible to surely prevent a liquid or mist coolant used in machining of the work W from entering into the machine room R1 from the opening window 20a. Accordingly, it is possible to protect parts such as various sensors, limit switches, or the like mounted on the machining unit U, or sliding portions of the Z-axis drive mechanism. (2) In the embodiment, since the entire outer peripheral surface of the body of the machining head 15 is constantly put into sliding contact with the seal lip 22a of the scraper 22, coolant or chip adhering to the outer peripheral surface of the machining head is scraped toward a tip end side of the outer peripheral surface of the body of the machining head 15 to be removed when the machining work is terminated and the machining head 15 is retreated. Therefore, coolant or chip is not taken into the machine room R1 by advancing or retreating movements. (3) In the embodiment, when the machining head 15 is moved to the tool exchange position within the machine room R1 from within the machining room R2, the machining head 15 is separated from the seal lip 22a of the scraper 22. At this time, coolant or chip adhering to the outer peripheral surface of the machining head 15 is removed by the seal lip 22a to be moved into the machine room R1 while being in a cleaned state. Therefore, coolant or chip is not taken into the machine room R1. (4) In the embodiment, since the protective cover 24 for shielding the machining unit U and the protective cover 25 for shielding the work support table 17 are provided on the bed 11 to compartment and form the machine room R1 and the machining room R2, it is possible to prevent coolant and chip from being scattered outside the machine tool in the machining of a work. (5) In the embodiment, the pair of right and left Z-axis guide rails 12 are laid immediately on the upper surface of the bed 11, and the Z-axis guide rails 12 mount thereon the Z-axis saddle 13 reciprocatively in the Z-axis direction. Therefore, a construction, in which the machining unit U is assembled to the bed 11, is made simple to enhance an assembling accuracy to enhance an accuracy, with which the drills 16 machine a work. (6) In the embodiment, since the seal frame can be detached from the compartment cover 20 by loosening the bolts 23, it is possible to readily exchange the seal frame. Subsequently, a modification of the first embodiment is described. In a modification shown in FIGS. 4 and 5, the machining unit U enables exchange of a plural kinds of machining heads 15 having different body sizes. Also, an opening window 20a is formed in the compartment cover 20 to serve as an opening, through which a machining head 15 having a maximum size can go in and out. Plural kinds of seal frames constituted by forming in a mount frame 21 an opening window 21a, which is sized to correspond to a body size of each of machining heads 15, and clamping a scraper 22 to the mount frame 21 with an adhesive and bolts 23a to make the same integral therewith to project inside the opening window 21a can be selectively and exchangeably mounted on the opening window 20a. As shown in FIG. 5, holes formed in the mount frame 21 for insertion of the bolts 23 comprise slots 21b positioned upward and directed vertically, and round holes 21c positioned downward and communicated to the slots 21b. Thus the round holes 21c are caused to correspond to heads of the bolts 23 in a state, in which the bolts 23 are loosened, and in this state, the mount frame 21 is permitted to be removed from the compartment cover 20 while the bolts 23 are left. In addition, since a reference position of the machining head 15 is set by a jig (not shown), which positions an underside of the machining head 15, and a jig, which positions a left side of the machining head 15, the opening window 21a of the mount frame 21 is also formed to have a shape, an underside and a left side of which serve as reference positions in accordance with mount positions of the respective machining head 15, and which are varied in size. In the modification shown in FIGS. 4 and 5, since mounting is effected so as to enable exchanging plural kinds of seal frames, the case where a body size of the machining head 15 of the machining unit U is modified can be readily met. In a modification shown in FIG. 6, the machining unit U enables exchanging any one of plural kinds of machining heads 15 having different body sizes, and the opening window 20a conformed to a maximum body size of the machining heads 15 is formed in the compartment cover 20. Also, plural kinds of head covers 26 formed into complementary shapes so as to assume the same shape as the external shape of a body of the machining head 15 having the maximum body size upon mounting on those machining heads 15 having sizes, which are equal to or less in size than the maximum body size, are selectively and exchangeably mounted on the machining unit U. A seal member 27 is mounted on an opening edge of an inner periphery of the head cover 26 to be generally put into contact with the outer peripheral surface of the machining head 15. The head cover 26 is formed, as shown in FIG. 7, into an elbow shape as viewed in an axial direction of the machining head 15 in terms of setting of a reference position of the machining head 15. Mounting of the head cover 26 on the machining head 15 is effected on, for example, a front surface of the column 14, or the outer peripheral surface of the machining head 15 by a connection member (not shown). In the above modification, different kinds of machining heads 15 can be readily exchanged only by exchange of the head cover 26 without modifying a seal frame on a side of the opening window 20a of the compartment cover 20. Second Embodiment Subsequently, a second embodiment of the invention is described with reference to FIGS. 8 to 10. In addition, those members in second and third embodiments, which have the same function as that in the first embodiment, are denoted by the same reference characters and an explanation thereof is omitted. In the second embodiment, as shown in FIG. 8, Y-axis guide rails 31 directed in a Y-axis direction (vertical) is provided on the front surface of the column 14, and a Y-axis saddle 32 is mounted on the Y-axis guide rails 31 such that it can be reciprocated vertically by a Y-axis drive mechanism (not shown) including a servomotor. The machining head 15 is mounted on a front surface of the Y-axis saddle 32. A roll cover mechanism 33 is mounted on the Z-axis saddle 13 and the column 14 to serve as a shield cover to allow up-and-down movements of the machining head 15 and to protect the outer peripheral surface of the body of the machining head 15, the Y-axis guide rails 31, and the Y-axis saddle 32. FIG. 9 shows a front surface of the roll cover mechanism 33, and FIG. 8 is a longitudinal cross sectional view showing a central portion of the roll cover mechanism 33. As shown in FIG. 9, a frame 34 constituting the roll cover mechanism 33 is composed of a pair of left and right side plates 34a, 34b, an upper casing 34c bridged between upper ends of the both side plates 34a, 34b, and a lower casing 34d bridged between lower ends of the both side plates 34a, 34b to have a longitudinal, rectangular shape, and an opening window 34e is formed inside the frame. The upper casing 34c is connected to left and right sides of the column 14 by means of a pair of left and right connection rods 35 as shown in FIG. 8. The lower casing 34d is connected to the Z-axis saddle 13 by means of a bracket 36. The machining head 15 is inserted, as shown in FIG. 8, through the opening window 34e formed in the frame 34 to be able to go up and down within the opening window, and a space defined between an upper surface of the body of the machining head 15 and the upper casing 34c is shielded by an upper roll cover K1. Also, a space defined between a lower surface of the body of the machining head 15 and the lower casing 34d is shielded by a lower roll cover K2. Since the upper and lower roll cover K1, K2 are formed to be vertically symmetrical, only the upper roll cover K1 is described. A connection frame 37, a front surface of which forms a longitudinal, rectangular shape, is mounted on a prismatic-shaped outer peripheral surface of the body of the machining head 15, and a rubber seal plate 38 for sealing a gap between the machining head 15 and the connection frame 37 is joined to the front surface of the connection frame 37. Horizontally extending band-shaped mount plates 39 are connected to a back surface side of the connection frame 37 by means of bolts 40. A lower end edge of a cover sheet 41 is connected to the mount plate 39 by means of a clamp plate 42 and rivets 43. An upper end edge of the cover sheet 41 is connected to an upper winding shaft 46 via guide rollers 44, 45 provided between the pair of side plates 34a, 34b. For example, a spiral spring (not shown) is received in the upper winding shaft 46 to constantly wind up the cover sheet 41. A scraper 47 is mounted to the opening window 34e of the frame 34 by screws 48 to come into sliding contact with a surface of the cover sheet 41. Subsequently, an action of the machine tool according to the second embodiment is described. FIG. 8 shows a state, in which the machining unit U and the roll cover mechanism 33 are disposed in a withdrawal position within the machining room R2. In this state, when the Y-axis saddle 32 is moved upward by a Y-axis drive mechanism (not shown), the machining head 15 is moved upward. In keeping with such action, the cover sheet 41 on a side of the upper roll cover K1 is wound up by the upper winding shaft 46, and the cover sheet 41 on a side of the lower roll cover K2 is wound off from a lower winding shaft 46′. In this manner, the machining head 15 is held at a desired level. In this state, when the machining unit U is advanced in the Z-axis direction from the withdrawal position within the machining room R2 by the Z-axis drive mechanism (not shown), a tip end of the frame 34 is moved to a machining work position as shown by two-dot chain lines in FIG. 8 and the drills 16 machine a work. In the second embodiment, the machining head 15 is mounted to be enabled by the Y-axis drive mechanism to to go up and down, and the roll cover mechanism 33 is mounted on the Z-axis saddle 13 and the column 14 to allow up-and-down movements of the machining head 15. And an outer peripheral surface of the frame 34 is put into sliding contact with an inner peripheral surface of the seal lip 22a. Therefore, it is possible to prevent coolant and chip from entering the machine room R1 in the machining of a work. In the embodiment, a telescopic cover mechanism may be used in place of the roll cover mechanism 33. Third Embodiment Subsequently, a third embodiment of the invention is described with reference to FIGS. 11 and 12. In the third embodiment, a X-axis saddle 73 is mounted on X-axis guide rails 72, which are laid on the upper surface of the Z-axis saddle 13 as shown in FIG. 11 to be in parallel to each other in a X-axis direction (direction perpendicular to a plane of the drawing), such that it can be reciprocated in the X-axis direction, and the column 14 is mounted on an upper surface of the X-axis saddle 73. Also, a roll cover mechanism 33 provided with the same cover sheet 41 as that of the roll cover mechanism 33 is laterally mounted on the support frame 19. Guide members 75 are mounted longitudinally in two locations on the sides of the column 14 to guide a base end portion of a guide bar 74 in the Z-axis direction. A front end portion of the guide bar 74 is bent upward into a L-shape, and a tip end of the front end portion is connected through connection plates 76 to a corner portion (see FIG. 12) of the cover sheet 41 of the roll cover mechanism 33. The guide bar 74 is supported by the guide members 75 to be non-rotatable about the Z-axis and slidable in the Z-axis direction. In the third embodiment, the guide bar 74, the guide members 75, the connection plates 76, and so on constitute interlocking unit for interlocking the machining unit U and the cover sheet 41 together in the X-axis direction to have the machining head 15 and the scraper 22 following the same correspondingly in the Z-axis direction. An action of the machine tool according to the third embodiment is described. Solid lines in FIG. 11 indicate a state, in which the machining unit U is stopped in the tool exchange position within the machine room R1 and the drills 16 are separated from the scraper 22. In this state, when the X-axis saddle 73 is moved along the X-axis guide rails 72 in the X-axis direction by a X-axis drive mechanism (not shown), the guide bar 74 is moved in the direction. Thereby, the cover sheet 41 and the scraper 22 are moved in the direction and the opening window 34e of the scraper 22 is held to correspond to the machining head 15 in the X-axis direction. When the Z-axis drive mechanism moves the machining unit U forward in the Z-axis direction after a position of the machining head 15 is adjustably moved in the X-axis direction, the tip end of the body of-the machining head 15 enters an inner peripheral surface of the seal lip 22a of the scraper 22 as shown by two-dot chain lines in FIG. 11 to be put in a sealed state. In this state, the drills 16 machine a work. Also, in the third embodiment, a withdrawal position within the machining room R2 corresponds to a state, in which the outer peripheral surface of the body of the machining head 15 contacts with the scraper 22. In the third embodiment, even when the guide bar 74 and the guide members 75 positionally adjust the machining head 15 in the X-axis direction, the machining head 15 and the scraper 22 on a side of the roll cover mechanism 33 can be held on the same axis with respect to the Z-axis direction. In addition, the embodiments may be modified in the following manner. The first embodiment may be configured such that slots (not shown) permitting insertion of the bolts 23 are provided in the compartment cover 20, nuts thread on the bolts 23, and the nuts are loosened to move the bolts 23 in the slots to be able to adjust a mount position of the seal frame. The second embodiment may be configured such that although not shown, the machining head 15 is mounted through the X-axis saddle on the Y-axis saddle 32 and the roll cover mechanism 33 or the telescopic cover mechanism 51 can extend and contract independently in the X-axis direction and the Y-axis direction. While the protective cover 24 and the protective cover 25 are arranged in the embodiments, they may be omitted. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to a machine tool for advancing and retreating a machining unit from a work supported on a work support table to perform machining of a work, and more particular, to a cover construction. 2. Description of the Related Art Generally, a machine tool comprises a work support table for supporting a work being machined, and a machining unit capable of mounting and dismounting of tools, which perform machining, such as drilling or the like, of the work. The machining unit is composed of a Z-axis saddle mounted on a bet to be able to reciprocate in a Z-axis direction (longitudinally), a column mounted on the Z-axis saddle, and a machining head mounted on the column to grasp tools. And the machining unit is advanced to perform machining of a work, and when machining is terminated, the machining unit is retreated. Also, the column is mounted on the Z-axis saddle to be able to reciprocate in a X-axis direction (laterally). Further, there are some configurations, in which a X-axis saddle for reciprocation relative to the column in a Y-axis direction (vertically) is mounted, the machining head is mounted on the Y-axis saddle, and the machining unit is moved in three axial directions, that is, X-axis direction, Y-axis direction, and Z-axis direction. While the machining head performs machining of a work, coolant containing a cutting oil for cooling and lubrication of tools and a work is supplied. When such coolant and chip enter into a machine region on a side of the machining unit from the machining head, a harmful influence is exerted on various sensors and limit switches provided on the machining unit, or slide members, seal members, or the like on X-axis, Y-axis, and Z-axis drive mechanisms. Therefore, a cover device is provided between the machining unit and a work support table. There has been heretofore proposed as such cover device an arrangement, in which an opening window for taking the machining head in and out in a X-axis direction (longitudinally) is provided on a stationary-side cover for compartment and formation of a machining room of a work, and a movable cover for shielding to prevent scattering of coolant outside from the opening window during machining of a work is provided on an outer peripheral surface of the machining head to be close to an opening window of a compartment cover. A configuration (JP-UM-A-4-115554) similar to the conventional configuration is shown in FIG. 3 . Also, a conventional cover device for machine tools is disclosed and proposed in JP-A-6-210531. The cover device is constructed such that a cylindrical-shaped opening of a protective cover surrounding a periphery of a machining head is fitted onto an opening window of a compartment cover in a manner to be able to advance and retreat. Since the conventional cover device, disclosed in JP-UM-A-4-115554, for machine tools is not constructed such that a movable cover is brought into close contact with the opening window of the compartment cover during machining of a work, however, there are caused problems that sealing is made incomplete, and a part of coolant enters into a machine region on a side of the machining unit because the movable cover is opened downward. Further, the cover device cannot cope with the case where a machining unit is of a type, in which tools are driven left and right, and up and down. In recent years, coolant as developed has an adverse influence on equipments such as sensors, limit switches, and so on, and seal members, and so a solution therefor has been demanded. Meanwhile, the cover device, disclosed in JP-A-6-210531, for machine tools is not constructed such that the cylindrical-shaped opening of the protective cover is brought into close contact with the opening window of the compartment cover during machining of a work. Therefore, the machining unit is retreated into a machine region in a state, in which coolant and chip adhere to an outer peripheral surface of the cylindrical-shaped opening, so that the machine region is made dirty. Besides, since an inside of the cylindrical-shaped opening is put in an opened state, coolant, chip, and scraps accumulate therein to be taken into the machine region during retreating of the machining unit while coolant and chip remain adhered to a peripheral surface of the machining head. | <SOH> SUMMARY OF THE INVENTION <EOH>It is a first object of the invention to dissolve problems involved in the prior art-and to provide a machine tool of a type, in which a machining unit is advanced at the time of machining of a work, and which can prevent coolant and chip from entering a side of the machining unit during machining of a work and can surely prevent coolant and chip from being taken into a machine region due to retreating of the machining unit. In addition to the first object, it is a second object of the invention to provide a machine tool, in which a machining unit can be moved in a transverse direction or in a vertical direction and which comprises a cover construction capable of preventing coolant and chip from entering a side of the machining unit during machining. In order to solve the above problems, according to a first aspect resides in a machine tool comprising a support table provided on an upper surface of a bed to support a work, a Z-axis saddle for reciprocation toward in a Z-axis direction (longitudinally), and a machining unit mounted on the Z-axis saddle and provided with a machining head for machining of the work, and wherein a compartment cover is arranged on the bed to compartment a region, in which a work supported on the support table is machined, and a machine region, in which the machining unit is movably arranged, an opening window is provided on the compartment cover to permit the machining head to go in and out therethrough, a seal member in the form of a closed ring to be mounted on an inner peripheral edge of the opening window of the compartment cover, and an entire periphery of an outer peripheral surface of the machining head is brought into sliding contact with an inner peripheral edge of the seal member in a state, in which the machining head is moved into the machining region from a tool exchange position within the machine region. According to a second aspect resides in that constitution as set forth in the first aspect, in which the machining unit is configured to permit exchange of plural kinds of machining heads having different body sizes, an opening is formed in the compartment cover to enable a machining head of a maximum size to go in and out, and the opening selectively and exchangeably mounts thereto plural kinds of seal frames comprising a mount frame formed with the opening window conformed to a body size of each of the machining heads, and the seal member mounted to an inner peripheral edge of the opening window of the mount frame and put into contact with an outer peripheral surface of a body of the machining head. According to a third aspect resides in that constitution as set forth in the first aspect, in which the machining unit is configured to permit exchange of plural kinds of machining heads having different body sizes, the seal member conformed to a maximum body size of the machining heads is mounted to the opening window of the mount frame, plural kinds of head covers formed into complementary shapes so as to assume the same shape as the external shape of a body of the machining head having the maximum body size upon mounting on those machining heads having sizes, which are equal to or less in size than the maximum body size, are selectively and exchangeably mounted on the machining unit, and a seal member is mounted on an inner edge of the head cover to come into contact with the outer peripheral surface of the machining head. According to a fourth aspect resides in that constitution as set forth in the first aspect, in which the machining head is mounted to be able to reciprocate in a X-axis direction (laterally) or a Y-axis direction (vertically), a shield cover is mounted on the machining unit to shield the machining head and to allow reciprocatory movements of the machining head in the X-axis direction (laterally) or the Y-axis direction (vertically), and an outer peripheral surface of an annular frame constituting the shield cover is brought into sliding contact with an inner peripheral surface of the seal member on a side of the opening window in a state, in which the machining head is moved into the machining region from a tool exchange position within the machine region. According to a fifth aspect resides in that constitution as set forth in the first aspect, in which the compartment cover comprises an arch-shaped support frame provided upright in a predetermined position on the bed, and an extensible cover mounted inside the support frame to be able to reciprocate together with the seal member in a X-axis direction (laterally) or a Y-axis direction (vertically), and wherein interlocking unit is provided between the machining unit and the extensible cover to move the extensible cover and the seal member in the X-axis direction or the Y-axis direction so that the machining head corresponds to the seal member as viewed in a Z-axis direction when the machining unit is moved in the X-axis direction or the Y-axis direction. According to a sixth aspect resides in that constitution as set forth in the fourth or sixth aspect, in which the compartment cover comprises a roll cover or a telescopic cover. According to a seventh aspect resides in that constitution according to any one of the first to sixth aspect, in which guide rails are mounted immediately on the upper surface of the bed and the Z-axis saddle of the machining unit is mounted on the guide rails. According to a eighth aspect resides in that constitution according to any one of the first to seventh aspect, in which the seal member comprises a scraper having a seal lip and has its tip end directed toward the machining region. According to a ninth aspect resides in that constitution according to any one of the first to eighth aspect, in which the machining head comprises a multi spindle head provided with a plurality of tools. | 20040121 | 20070227 | 20060622 | 62457.0 | B23D7700 | 0 | CADUGAN, ERICA E | MACHINE TOOL | UNDISCOUNTED | 0 | ACCEPTED | B23D | 2,004 |
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10,760,420 | ACCEPTED | WHEEL RIM DEVICE WITH PATTERNED LIGHT CAPABLE OF AUTOMATICALLY GENERATING ELECTRIC POWER | A wheel rim device with patterned light capable of automatically generating electric power has a wheel rim, an automatic generating assembly, a rectifier/filter circuit, a circuit board, a programmable chip and several light emitting components. The automatic generating assembly is accommodated on an end face of a wheel axle of the wheel rim. The circuit board is disposed on a wheel spoke of the wheel rim. The rectifier/filter circuit, the programmable chip and the light emitting components are disposed on the circuit board. Input terminals of the rectifier/filter circuit are connected to lead-out wires of the automatic generating assembly. The programmable chip has a power source terminal, a trigger terminal and several I/O terminals. The power source terminal is connected with the output terminal of the rectifier/filter circuit. Each of the I/O terminals is connected with one of the light emitting components. | 1. A wheel rim device with patterned light capable of automatically generating electric power, the wheel rim device comprising: a wheel rim with wheel spokes and a wheel axle disposed thereon, an accommodating room being concavely provided on an end face of said wheel axle; an automatic generating assembly arranged in said accommodating room of said wheel rim for generating an AC voltage when said wheel rim rotates; a rectifier/filter circuit connected with said automatic generating assembly to rectify and filter the AC voltage generated by said automatic generating assembly to obtain a DC voltage; a circuit board connected on one said wheel spoke of said wheel rim and having a plurality of one light emitting components; and a programmable chip disposed on said circuit board and connected with said rectifier/filter circuit and said light emitting components, said programmable chip being used to drive said light emitting components to generate various glittering and jumping dynamic variations for accomplishing the effect of persistence of vision according to different timings of the output waveform of said programmable chip when said rectifier/filter circuit outputs a DC voltage, the color mixing effect being also accomplished between said light emitting components to display different color lights. 2. The wheel rim device as claimed in claim 1, wherein said programmable chip is formed by integrating an oscillator, a frequency selector, a ROM, a counter, a pattern memory and a buffer into a single chip microcontroller. 3. The wheel rim device as claimed in claim 2, wherein said programmable chip has a power source terminal, a trigger terminal and several I/O terminals, said power source terminal is connected to an output terminal of said rectifier/filter circuit, and each of said I/O terminals is connected with one of said light emitting components. 4. The wheel rim device as claimed in claim 1, wherein said automatic generating assembly is connected with one or more light emitting components. 5. The wheel rim device as claimed in claim 1, wherein said automatic generating assembly has a shell cover having a closed face, a first cavity and a second cavity are provided on an inner face of said shell cover, said first cavity is smaller than said second cavity, an induction coil is annularly disposed in said first cavity, a magnetic component is also assembled in said first cavity, a heavy hammer is pivotally disposed at an axle portion of said magnetic component, said heavy hammer is always maintained in a vertical direction due to gravity, said heavy hammer is disposed on an inner periphery face of said second cavity, lead-out wires are extended from two distal ends of said induction coil and connected to said rectifier/filter circuit, and said induction coil generates an induced electromotive force when said wheel rim rotates. 6. The wheel rim device as claimed in claim 1, wherein several holes are annularly disposed on an inner face of said accommodating room of said wheel rim. 7. The wheel rim device as claimed in claim 1, wherein positioning components are annularly disposed on an outer periphery face of said shell cover of said automatic generating assembly, and several screwing components pass through said positioning components to be firmly screwed to said holes of said wheel axle. 8. The wheel rim device as claimed in claim 1, wherein said rectifier/filter circuit is disposed on said circuit board. 9. A wheel rim device with patterned light capable of automatically generating electric power comprising: a wheel rim having a wheel rim cover, an accommodating room being concavely provided in said wheel rim cover; an automatic generating assembly arranged in said accommodating room of said wheel rim cover for generating an AC voltage when said wheel rim rotates; a rectifier/filter circuit connected with said automatic generating assembly to rectify and filter the AC voltage generated by said automatic generating assembly to obtain a DC voltage; a cover plate connected with said accommodating room of said wheel rim cover; a circuit board connected on said wheel rim cover and having more than one light emitting components; and a programmable chip disposed on said circuit board and connected with said rectifier/filter circuit and said light emitting components, said programmable chip being used to drive said light emitting components to generate various glittering and jumping dynamic variations for accomplishing the effect of persistence of vision according to different timings of the output waveform of said programmable chip when said rectifier/filter circuit outputs a DC voltage, the color mixing effect being also accomplished between said light emitting components to display different color lights. 10. The wheel rim device as claimed in claim 9, wherein said programmable chip is formed by integrating an oscillator, a frequency selector, a ROM, a counter, a pattern memory and a buffer into a single chip microcontroller. 11. The wheel rim device as claimed in claim 10, wherein said programmable chip has a power source terminal, a trigger terminal and several I/O terminals, said power source terminal is connected to an output terminal of said rectifier/filter circuit, and each of said I/O terminals is connected with one of said light emitting components. 12. The wheel rim device as claimed in claim 9, wherein said automatic generating assembly is connected with one or more light emitting components. 13. The wheel rim device as claimed in claim 9, wherein said light emitting components are assembled on said wheel rim cover. 14. The wheel rim device as claimed in claim 9, wherein said light emitting components are assembled on both said wheel rim cover and said cover plate. 15. The wheel rim device as claimed in claim 9, wherein said automatic generating assembly has a shell cover having a closed face, a first cavity and a second cavity are provided on an inner face of said shell cover, said first cavity is smaller than said second cavity, an induction coil is annularly disposed in said first cavity, a magnetic component is also assembled in said first cavity, a heavy hammer is pivotally disposed at an axle portion of said magnetic component, said heavy hammer is always maintained in a vertical direction due to gravity, said heavy hammer is disposed on an inner periphery face of said second cavity, lead-out wires are extended from two distal ends of said induction coil and connected to said rectifier/filter circuit, and said induction coil generates an induced electromotive force when said wheel rim rotates. 16. The wheel rim device as claimed in claim 9, wherein positioning components are annularly disposed on an outer periphery face of said shell cover of said automatic generating assembly, and several screwing components pass through said positioning components to be firmly screwed to said wheel rim cover. | FIELD OF THE INVENTION The present invention relates to a wheel rim device with patterned light capable of automatically generating electric power and, more particularly, to a device capable of controlling light emitting components disposed at a wheel rim to generate various glittering and jumping dynamic variations for accomplishing the effect of persistence of vision and also displaying different mixed color lights. BACKGROUND OF THE INVENTION In a conventional lighting structure disposed in a car wheel rim, a battery holder is arranged in the center of a wheel rim cover, a battery cover is installed on the battery holder, and a circuit board is installed in the battery holder. A light sensor is installed at the center of the outer side of the wheel rim cover. The light sensor is connected to the circuit board. A plurality of light emitting components is installed in symmetric positions on the periphery of the wheel rim cover. A centrifugal switch is also installed at the edge of the inner side of the wheel rim cover. When a car runs at a certain speed, the centrifugal switch is turned on. When night falls, the light sensor completes the circuit to let the light emitting components on the wheel rim cover emit light. Although the above light emitting structure has a light emitting function, if the battery on the battery holder runs out of power, the light emitting components won't work, and the light sensor also loses its function. If the wheel rim has a mechanism for automatically generating electric power, the above situation won't occur. Moreover, the order and dynamic light variations of the light emitting components can be controlled through circuit design for accomplishing the effect of persistence of vision and displaying different mixed color lights. SUMMARY OF THE INVENTION An object of the present invention is to provide a car wheel rim with a mechanism for automatically generating electric power. Moreover, light emitting components arranged on the mechanism can be controlled through special circuit design to generate various dynamic light variations for accomplishing the effect of persistence of vision and displaying different mixed color lights. To achieve the above object, the present invention proposes a wheel rim device with patterned light capable of automatically generating electric power. The wheel rim device comprises a wheel rim, an automatic generating assembly, a rectifier/filter circuit, a circuit board a programmable chip and several light emitting components. Wheel spokes and a wheel axle are disposed on the wheel rim. An accommodating room is concavely disposed on an end face of the wheel axle. The automatic generating assembly is accommodated in the accommodating room of the wheel rim, and can generate an AC voltage when the wheel rim rotates. The circuit board is disposed on one of the wheel spokes of the wheel rim. A plurality of one light emitting components is disposed on the circuit board. The rectifier/filter circuit is disposed on the circuit board, and is connected to the automatic generating assembly to rectify and filter the AC voltage generated by the automatic generating assembly to obtain a stable DC voltage. The programmable chip is disposed on the circuit board connected to the rectifier/filter circuit and the light emitting components. The programmable chip is used to drive the light emitting components to generate various glittering and jumping dynamic variations at different times and in different orders for accomplishing the effect of persistence of vision according to different timings of the output waveform of the programmable chip when the automatic generating assembly generates the AC voltage and the rectifier/filter circuit rectify and filter the AC voltage to obtain the DC voltage. Besides, the color mixing effect can also be accomplished between the light emitting components to display different color lights. The programmable chip is formed by integrating an oscillator, a frequency selector, a ROM, a counter, a pattern memory and a buffer into a single chip microcontroller. The programmable chip has a power source terminal, a trigger terminal and several I/O terminals. The power source terminal is connected to an output terminal of the rectifier/filter circuit. End each of the I/O terminals is connected with one of the light emitting components. The automatic generating assembly, the rectifier/filter circuit, and the circuit board also apply to a wheel rim having a wheel rim cover. Lead-out wires of the automatic generating assembly can also be connected to several light emitting components. BRIEF DESCRIPTION OF THE DRAWINGS 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: FIG. 1 is a perspective view of a first embodiment of the present invention; FIG. 2 is an exploded perspective view of FIG. 1; FIG. 3 is an exploded perspective view showing the connection between an automatic generating assembly and a circuit board of the present invention; FIG. 4 is an assembly view of FIG. 3; FIG. 5 is a circuit block diagram of the present invention; FIG. 6 is an inner block diagram of a programmable chip of the present invention; FIG. 7A is a timing diagram showing different frequencies output to light emitting components by a programmable chip of the present invention; FIG. 7B is a pattern variation diagram showing the effect of persistence of vision according to the timing of FIG. 7A; FIG. 8A is another timing diagram showing different frequencies output to light emitting components by a programmable chip of the present invention; FIG. 8B is a pattern variation diagram showing the effect of persistence of vision according to the timing of FIG. 8A; FIG. 9A is yet another timing diagram showing different frequencies output to light emitting components by a programmable chip of the present invention; FIG. 9B is a pattern variation diagram showing the effect of persistence of vision according to the timing of FIG. 9A; FIG. 10 is an exploded perspective view of a second embodiment of the present invention; FIG. 11 is an assembly view of FIG. 10; FIG. 12 is a perspective view of a third embodiment of the present invention; FIG. 13 is a perspective view of a fourth embodiment of the present invention; and FIG. 14 is a circuit block diagram according to the fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 to 6, a wheel rim device with patterned light capable of automatically generating electric power of the present invention comprises a wheel rim 1, a rectifier/filter circuit 7, an automatic generating assembly 2, a circuit board 3, a programmable chip 4 and several light emitting components 5. The wheel rim 1 is an aluminum alloy wheel rim, and is composed of a main body 11, wheel spokes 12 and a wheel axle 13. An accommodating room 131 is concavely disposed on an end face of the wheel axle. A plurality of holes 132 is formed on an inner face of the accommodating room 131. The automatic generating assembly 2 is connected in the accommodating room 131 of the wheel rim 1, and has a shell cover 21 having a closed face. Positioning components 22 are annularly disposed on an outer periphery face of the shell cover 21. Several screwing components pass through the positioning components to be firmly screwed to the holes of the wheel axle. Two cavities 22 and 23 are disposed on an inner face of the shell cover 21. The first cavity 22 is smaller than the second cavity 23. An inducting coil 24 is annularly disposed in the first cavity 22. A magnetic component 25 is also disposed in the first cavity 22. Lead-out wires 26 are extended from two distal ends of the induction coil 24 and pass through the closed face. A heavy hammer 251 is pivotally disposed at the axle center portion of the magnetic component 25. The heavy hammer 251 will always remain in the vertical direction during motion. The heavy hammer 251 is disposed on an inner periphery face of the second cavity 23. The rectify/filter circuit 7 is connected with the lead-out wires of the automatic generating assembly 2, and is composed of a bridge rectifier and a filter capacitor. The rectifier/filter circuit 7 is used to rectify and filter an AC voltage generated by the automatic generating assembly to obtain a DC voltage. In this embodiment, the circuit board 3 is connected on the wheel spoke 12 of the wheel rim 1. The circuit board 3 has several light emitting components 5 thereon. In this embodiment, there are six light emitting components P1-P6 of different colors. Each light emitting component is a light emitting diode (LED). One light emitting component (P6) is a blue LED, and is connected with the lead-out wires 26 of the automatic generating assembly 2. The programmable chip 4 is disposed on the circuit board 3, and is connected with the output terminal of the rectifier/filter circuit 7 and the light emitting components P1-P5. The programmable chip 4 is formed by integrating a 350 kHz oscillator 41, a frequency selector 42, a ROM 43, a counter 44, a pattern memory 45 and a buffer 46 into a single chip microcontroller. The programmable chip 4 has power source terminals VDD and VSS and several I/O terminals L1-L5. The I/O terminals L1-L5 are connected with the light emitting diodes P1-P5, respectively. The light emitting components 5 will generate various glittering and jumping dynamic variations at different times and in different orders for accomplishing the effect of persistence of vision according to different timings of the output waveform of the programmable chip when the programmable chip functions. Besides, the color mixing effect can also be accomplished between the light emitting components to display different color lights. When the wheel rim 1 rotates to let the induction coil 24 generate an inducted electromotive force, the light emitting diode P6 will be on, and the induction coil 24 will also provide power to the rectifier/filter circuit 7 to output an DC power to the programmable chip 4, thereby driving the light emitting diodes P1-P5. Meanwhile, the light emitting diodes P1-P5 will generate various glittering and jumping dynamic variations (FIGS. 7B, 8B and 9B) at different times and in different orders for accomplishing the effect of persistence of vision according to different timings of the output waveform (FIGS. 7A, 8A and 9A) of the programmable chip. Besides, the color mixing effect can also be accomplished between the light emitting components to display different color lights. Reference is made to FIG. 7A. The first to third light emitting diodes P1-P3 are driven by the programmable chip 4 to be on all the time, while the fourth and fifth light emitting diodes P4 and P5 are driven by the programmable chip 4 to be on and off at different rates. When the wheel rim 1 rotates, the pattern shown in FIG. 7B will be obtained. Reference is made to FIG. 8A. The second to the fourth light emitting diodes P2-P4 are driven by the programmable chip 4 to be on all the time, while the first and fifth light emitting diodes P1 and P5 are driven by the programmable chip 4 to be on and off at different rates. When the wheel rim 1 rotates, the pattern shown in FIG. 8B will be obtained. Reference is made to FIG. 9A. The third to the fifth light emitting diodes P3-P5 are driven by the programmable chip 4 to be on all the time, while the first and second light emitting diodes P1 and P2 are driven by the programmable chip 4 to be on and off at different rates. When the wheel rim 1 rotates, the pattern shown in FIG. 9B will be obtained. Reference is made to FIGS. 10 and 11. The automatic generating assembly 2, the rectifier/filter circuit 7, the circuit board 3, the control unit 4 and the light emitting components 5 of the present invention can also apply to a wheel rim 1 having a wheel rim cover 6. The wheel rim cover 6 is connected at an opening portion of the main body of the wheel rim 1. An accommodating space 61 is concavely formed at the center portion of the wheel rim cover 6. The automatic generating assembly 2 and a cover board 62 are connected in the accommodating space 61 in order. Screwing components 23 are used to firmly lock the automatic generating assembly 2 with the wheel rim cover 6. The circuit board 3 is connected on the surface of the cover board 62 of the wheel rim cover 6. When the wheel rim 1 rotates, the induction coil 24 will generate an inducted electromotive force to let the light emitting diode P6 be on and also provide power for the rectifier/filter circuit 7 to output a DC power to the programmable chip 4 for driving the light emitting components P1-P5. The light emitting components 5 will generate various glittering and jumping dynamic variations at different times and in different orders for accomplishing the effect of persistence of vision according to different timings of the output waveform of the programmable chip 4. Besides, the color mixing effect can also be accomplished between the light emitting components 5 to display different color lights. As shown in FIG. 12, the light emitting components 5 and the light emitting diode P6 can also be assembled on the wheel rim cover 6. As shown in FIGS. 13 and 14, several light emitting diodes P1-P8 can be assembled on the wheel rim cover 6 and the cover board 62 to add more variations. The light emitting diodes P1-P5 are connected to the I/O terminals L1-L5 of the programmable chip 4, while the light emitting diodes P6-P8 are connected to the lead-out wires 26 of the automatic generating assembly 2. When the wheel rim 1 rotates, the induction coil 24 will generate an inducted electromotive force to let the light emitting diodes P6-P8 be on and also provide power for the rectifier/filter circuit 7 to output a DC power to the programmable chip 4 for driving the light emitting components P1-P5. The light emitting components 5 will generate various glittering and jumping dynamic variations at different times and in different orders for accomplishing the effect of persistence of vision according to different timings of the output waveform of the programmable chip 4. Besides, the color mixing effect can also be accomplished between the light emitting components 5 to display different color lights. To sum up, through the novel structure and circuit design of the present invention, the light emitting components assembled on the wheel rim can be controlled to generate various glittering and jumping dynamic variations for accomplishing the effect of persistence of vision. Besides, the color mixing effect can also be accomplished to display different color lights. Although the present invention has been described with reference to the preferred embodiments 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. | <SOH> BACKGROUND OF THE INVENTION <EOH>In a conventional lighting structure disposed in a car wheel rim, a battery holder is arranged in the center of a wheel rim cover, a battery cover is installed on the battery holder, and a circuit board is installed in the battery holder. A light sensor is installed at the center of the outer side of the wheel rim cover. The light sensor is connected to the circuit board. A plurality of light emitting components is installed in symmetric positions on the periphery of the wheel rim cover. A centrifugal switch is also installed at the edge of the inner side of the wheel rim cover. When a car runs at a certain speed, the centrifugal switch is turned on. When night falls, the light sensor completes the circuit to let the light emitting components on the wheel rim cover emit light. Although the above light emitting structure has a light emitting function, if the battery on the battery holder runs out of power, the light emitting components won't work, and the light sensor also loses its function. If the wheel rim has a mechanism for automatically generating electric power, the above situation won't occur. Moreover, the order and dynamic light variations of the light emitting components can be controlled through circuit design for accomplishing the effect of persistence of vision and displaying different mixed color lights. | <SOH> SUMMARY OF THE INVENTION <EOH>An object of the present invention is to provide a car wheel rim with a mechanism for automatically generating electric power. Moreover, light emitting components arranged on the mechanism can be controlled through special circuit design to generate various dynamic light variations for accomplishing the effect of persistence of vision and displaying different mixed color lights. To achieve the above object, the present invention proposes a wheel rim device with patterned light capable of automatically generating electric power. The wheel rim device comprises a wheel rim, an automatic generating assembly, a rectifier/filter circuit, a circuit board a programmable chip and several light emitting components. Wheel spokes and a wheel axle are disposed on the wheel rim. An accommodating room is concavely disposed on an end face of the wheel axle. The automatic generating assembly is accommodated in the accommodating room of the wheel rim, and can generate an AC voltage when the wheel rim rotates. The circuit board is disposed on one of the wheel spokes of the wheel rim. A plurality of one light emitting components is disposed on the circuit board. The rectifier/filter circuit is disposed on the circuit board, and is connected to the automatic generating assembly to rectify and filter the AC voltage generated by the automatic generating assembly to obtain a stable DC voltage. The programmable chip is disposed on the circuit board connected to the rectifier/filter circuit and the light emitting components. The programmable chip is used to drive the light emitting components to generate various glittering and jumping dynamic variations at different times and in different orders for accomplishing the effect of persistence of vision according to different timings of the output waveform of the programmable chip when the automatic generating assembly generates the AC voltage and the rectifier/filter circuit rectify and filter the AC voltage to obtain the DC voltage. Besides, the color mixing effect can also be accomplished between the light emitting components to display different color lights. The programmable chip is formed by integrating an oscillator, a frequency selector, a ROM, a counter, a pattern memory and a buffer into a single chip microcontroller. The programmable chip has a power source terminal, a trigger terminal and several I/O terminals. The power source terminal is connected to an output terminal of the rectifier/filter circuit. End each of the I/O terminals is connected with one of the light emitting components. The automatic generating assembly, the rectifier/filter circuit, and the circuit board also apply to a wheel rim having a wheel rim cover. Lead-out wires of the automatic generating assembly can also be connected to several light emitting components. | 20040121 | 20050830 | 20050721 | 63591.0 | 6 | PHILOGENE, HAISSA | WHEEL RIM DEVICE WITH PATTERNED LIGHT CAPABLE OF AUTOMATICALLY GENERATING ELECTRIC POWER | SMALL | 0 | ACCEPTED | 2,004 |
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10,760,445 | ACCEPTED | Cranberry-harvesting apparatus and method | An apparatus and method for harvesting cranberries, the method including moving frame-mounted transverse dislodging rods over cranberry plants with each rod moving at the speed of the frame, thereby to dislodge cranberries from the cranberry plants. The apparatus includes a plurality of dislodging rods secured below the frame, the dislodging rods positioned substantially parallel to the field surface and generally perpendicular to the direction of movement whereby each dislodging rod is moved through the cranberry plants at the speed of the frame to dislodge the cranberries from the plants. Certain preferred embodiments use follower assemblies to configure an array of dislodging rods in an advantageous arrangement. | 1. A cranberry-harvesting apparatus comprising: a frame movable over a field of cranberries in a forward direction; a plurality of follower assemblies each secured to and below the frame by a support, each follower assembly including: a rod mount having a lower portion, a surface-following leading end, and a pivot attachment to the support at the lower portion behind the center-of-gravity of the follower assembly; and first and second pairs of dislodging rods mounted to the rod mount forward and rearward of the pivot attachment respectively, each pair extending laterally from opposite sides of the lower portion substantially parallel to the field surface and canted rearwardly, whereby each rod mount is supported such that it moves through the cranberry plants at the speed of the frame to dislodge the cranberries from the plants. 2. The cranberry-harvesting apparatus of claim 1 wherein the first and second pairs of dislodging rods are spring-mounted such that the dislodging rods deflect under load in a plane substantially parallel to the field surface. 3. The cranberry-harvesting apparatus of claim 2 wherein: the rod mount is a vertical plate having spring posts extending downward to the lower portion; and each dislodging rod bas a coiled proximal end forming a spring coiled around one of the spring posts. 4. The cranberry-harvesting apparatus of claim 3 further including feet extending from the lower portion rearwardly below each pair of spring posts whereby the feet reduce entanglement of plants with the spring posts. 5. The cranberry-harvesting apparatus of claim 1 wherein the dislodging rods have a substantially circular cross-section. 6. The cranberry-harvesting apparatus of claim 1 wherein: the frame has a major axis generally perpendicular to the movement thereof and parallel to the field surface; each dislodging rod has a free distal end; the follower assemblies are laterally spaced substantially equally along the major axis in alternating forward and rearward positions thereby forming offset forward and rearward gangs of adjacent assemblies such that the distal ends of the dislodging rods of adjacent assemblies overlap along the major axis; and the distal ends of the dislodging rods of adjacent assemblies of each gang are spaced apart along the direction of movement. 7. The cranberry-harvesting apparatus of claim 6 wherein the space along the direction of movement between the dislodging rod distal ends of adjacent follower assemblies is at least four inches. 8. The cranberry-harvesting apparatus of claim 6 wherein: the frame includes a principal cross-member; and each support includes a longitudinal arm pivotably mounted to the cross-member. 9. The cranberry-harvesting apparatus of claim 8 wherein each longitudinal arm is downwardly spring-biased against the field surface. 10. The cranberry-harvesting apparatus of claim 9 wherein each support further includes: an anchor arm affixed to the cross-member and having a first connection spaced therefrom; a second connection on the longitudinal arm spaced from the cross-member; and a spring linkage between the first and second connections such that the longitudinal arm moves under load with respect to the anchor arm to provide the downward biasing. 11. The cranberry-harvesting apparatus of claim 1 wherein each surface-following leading end is substantially convex. 12. The cranberry-harvesting apparatus of claim 1 wherein the frame is operator-movable up and down such that the surface-following leading ends can be positioned in and out of contact with the field surface. 13. The cranberry-harvesting apparatus of claim 1 wherein the space between the first and second pairs of dislodging rods is at least twelve inches. 14. The cranberry-harvesting apparatus of claim 1 wherein the cant angle of the dislodging rods is between 15 and 40 degrees from the major axis. 15. The cranberry-harvesting apparatus of claim 1 further including a drive apparatus to move the frame over a field of cranberries. 16. The cranberry-harvesting apparatus of claim 15 wherein the frame is mounted to the front of the drive apparatus. 17. The cranberry-harvesting apparatus of claim 15 wherein the frame is mounted to the back of the drive apparatus. 18. The cranberry-harvesting apparatus of claim 1 further including at least one vacuum nozzle behind the follower assemblies whereby the dislodged cranberries are picked up by vacuum suction. 19. The cranberry-harvesting apparatus of claim 18 wherein the at least one vacuum nozzle includes one vacuum nozzle behind each of the follower assemblies. 20. The cranberry-harvesting apparatus of claim 18 further including a collection container. 21. A cranberry-harvesting apparatus comprising: a frame movable over a field of cranberries in a forward direction; and a plurality of dislodging rods secured to and below the frame wherein the dislodging rods have a spring at the proximal end thereof spring-mounting the dislodging rod to a vertical plate, the dislodging rods positioned substantial in a single plane substantially transverse to the field surface and generally perpendicular to the direction of movement, whereby each dislodging rod is moved through the cranberry plants at the speed of the frame to dislodge the cranberries from the plants. 22. The cranberry-harvesting apparatus of claim 21 wherein the dislodging rods are angled slightly rearwardly. 23. The cranberry-harvesting apparatus of claim 21 wherein the dislodging rods have a free-distal end and a spring-mounted proximal end such that the dislodging rods deflect under load in a plane substantially parallel to the field surface. 24. The cranberry-harvesting apparatus of claim 21 wherein the dislodging rods are secured to the frame by being secured to follower assemblies each having forward and rearward pairs of dislodging rods. 25. The cranberry-harvesting apparatus of claim 24 wherein the follower assemblies are mounted to the frame in alternating forward and rearward positions. 26. A method of harvesting cranberries from a cranberry field including moving frame-mounted, free-ended dislodging rods wherein each dislodging rod is spring-mounted to the frame and oriented transverse to the direction of movement of the frame, over cranberry plants with each rod moving at the speed of the frame thereby to dislodge cranberries from the cranberry plants. 27. A method of harvesting cranberries from a cranberry field including moving frame-mounted, free-ended dislodging rods, wherein each dislodging rod is spring-mounted to the frame and oriented transverse to the direction of movement of the frame, over cranberry plants with each rod moving at the speed of the frame, thereby to dislodge cranberries from the cranberry plants. 28. The method of claim 27 further including the steps of vacuuming up dislodged cranberries immediately after dislodgement and collecting the cranberries in a container. | FIELD OF THE INVENTION This invention is related to cranberry harvesting and, more particularly, to cranberry-harvesting equipment and methods. BACKGROUND OF THE INVENTION Cranberries are raised in fields or bogs, which are relatively flat areas divided into sections so that the fields can be flooded both to facilitate harvesting and to protect the vines from frost. The cranberry plants form a mat of vines which may be up to twelve or fourteen inches deep. During harvesting, the berries are removed from the vines and float to the surface of the water. The berries are then gathered up for transport to a processing facility. Traditional methods of harvesting cranberries and the equipment used to implement such methods generally fall into two categories. Both traditional methods have drawbacks which will be described herein later. The first general method can be characterized as “beating” and is carried out using equipment which includes beaters which are bars mounted on combine-like revolving structures. U.S. Pat. No. 3,672,140 (Burford) discloses equipment based on this principal. As the harvesting vehicle moves through the cranberry bog, a rotating wheel with transverse bars to agitate the cranberry vines, causes the cranberries to detach from the plants. The rotation of the wheel causes the transverse bars to move through the cranberry vines at a speed greater than the vehicle speed at the position of principal contact with the plants. Cranberries float to the surface of the flooded bog and are gathered up. U.S. Pat. No. 4,501,111 issued to Abbott describes another harvester unit which uses such a rotating wheel approach. The second general method can be characterized as picking or raking. U.S. Pat. No. 2,524,631 (Minutillo) describes a harvesting machine based on this method. A series of combs mounted on a rotating wheel is moved through the cranberry plants to detach the cranberries from the vines. U.S. Pat. No. 5,067,047 (Rosset) discloses harvesting equipment which employs vertically-oscillating tines to strip the cranberries from the vines. Rosset then collects the stripped cranberries through a vacuum suction unit. As mentioned above, the methods and equipment which are used for cranberry harvesting have certain drawbacks. As in any commercial endeavor, increased productivity is in general a desired performance. Typical harvesting rates for the cranberry-harvesting equipment commonly used today is on the order of 0.5 acres per hour, with maximum rates being about 1.5 acres per hour. Productivity is also affected by the fraction of the fruit which is removed from the vines during harvesting. A higher fraction yields higher productivity. Some of this equipment is quite “aggressive” in how it treats the cranberry plants, often resulting in damage both to harvested fruit as well as the vines. In addition, much of the equipment used today includes a number of moving parts, often driven by hydraulic equipment. The operation of hydraulic equipment during harvesting creates the risk of the fruit becoming contaminated with hydraulic fluid. Also, the complexity of the equipment translates into increased maintenance cost. Finally, for cranberries which are sold as fresh fruit rather than processed into juice or other consumer food products, not only is it advantageous to prevent damage to the fruit, it is also of great benefit to avoid wetting the fruit during harvesting. As mentioned above, the fields or bogs are flooded, allowing the fruit which has been separated from the plants to float, thereby facilitating the collection of the fruit. However, the fruit, being now wet, is subject to the growth of fungus or requires the additional costly step of drying in order to deliver fresh, unblemished fruit to the market. Because of this, it is advantageous to dry-harvest cranberries to avoid these problems or costs. Therefore, there is a need for simple, rapid and efficient, low-cost method and apparatus to harvest cranberries. OBJECTS OF THE INVENTION It is an object of this invention, in the field of cranberry-harvesting, to provide a cranberry-harvesting apparatus and method which harvest cranberries at substantially higher rates (acres per hour) than existing harvesting equipment and methods. Another object is to provide cranberry-harvesting apparatus which is mechanically simple and requires a minimum of maintenance. Another object is to a provide cranberry-harvesting apparatus and method which remove a higher fraction of the cranberries from the vines than existing harvesting equipment and method. Another object is to provide cranberry-harvesting apparatus which can be both pushed or pulled through the field of cranberry vines. Another object is to provide cranberry-harvesting apparatus which reduces the risk of contamination of the fruit being harvested. Still another object is to provide cranberry-harvesting apparatus which reduces the damage to the cranberries being harvested. Yet another object is to provide a cranberry-harvesting apparatus and method which can be used for both wet and dry harvesting of cranberries. These and other objects of the invention will be apparent from the following descriptions and from the drawings. SUMMARY OF THE INVENTION The invention is a method and apparatus for harvesting cranberries, whereby frame-mounted transverse dislodging rods are moved over cranberry plants with each rod moving at the speed of the frame, thereby dislodging cranberries from the cranberry plants. The cranberry-harvesting apparatus of this invention comprises a frame movable over a field of cranberries in a forward direction with a plurality of follower assemblies each secured to and below the frame by a support. Each follower assembly includes: a rod mount having a lower portion, a surface-following leading end, and a pivot attachment to the support at the lower portion behind the center-of-gravity of the follower assembly; and first and second pairs of dislodging rods mounted to the rod mount forward and rearward of the pivot attachment respectively, each pair extending laterally from opposite sides of the lower portion substantially parallel to the field surface and canted rearwardly. Each rod mount is supported such that it moves through the cranberry plants at the speed of the frame to dislodge the cranberries from the plants. In certain highly preferred embodiments of the inventive cranberry-harvesting apparatus, the first and second pairs of dislodging rods are spring-mounted such that the dislodging rods deflect under load in a plane substantially parallel to the field surface. In another preferred embodiment of the cranberry-harvesting apparatus, each rod mount is a vertical plate having spring posts extending downward to the lower portion, and each dislodging rod has a coiled proximal end forming a spring coiled around one of the spring posts. Certain preferred embodiments of such apparatus further include feet extending from the lower portion rearwardly below each pair of spring posts for the purpose of reducing the entanglement of plants with the spring posts. In another preferred embodiment of the apparatus, the dislodging rods have a substantially circular cross-section. In highly preferred embodiments of the cranberry-harvesting apparatus, the frame has a major axis generally perpendicular to the movement thereof and parallel to the field surface. Each dislodging rod has a free distal end, and the follower assemblies are laterally spaced substantially equally along the major axis in alternating forward and rearward positions thereby forming offset forward and rearward gangs of adjacent assemblies such that the distal ends of the dislodging rods of adjacent assemblies overlap along the major axis. The distal ends of the dislodging rods of adjacent assemblies of each gang are spaced apart along the direction of movement. In certain other embodiments of the inventive cranberry-harvesting apparatus, the space along the direction of movement between the dislodging rod distal ends of adjacent follower assemblies is at least four inches. In highly-preferred embodiments of the cranberry-harvesting apparatus, the frame includes a principal cross-member, and each support includes a longitudinal arm pivotably mounted to the cross-member. In some embodiments of the cranberry-harvesting apparatus, each longitudinal arm is downwardly spring-biased against the field surface. In such embodiments, it is most preferred that such apparatus include: an anchor arm affixed to the cross-member and having a first connection spaced therefrom; a second connection on the longitudinal arm spaced from the cross-member; and a spring linkage between the first and second connections such that the longitudinal arm moves under load with respect to the anchor arm to provide the downward biasing. In some embodiments, each surface-following leading end is substantially convex. In other embodiments of the cranberry-harvesting apparatus, the frame is operator-movable up and down such that the surface-following leading ends can be positioned in and out of contact with the field surface. In another preferred embodiment of the inventive apparatus, the space between the first and second pairs of dislodging rods is at least twelve inches. In addition, in some preferred embodiments, the cant angle of the dislodging rods is between 15 and 40 degrees from the major axis. Some highly-preferred embodiments of the invention further include a drive apparatus to move the frame over a field of cranberries. In some embodiments, the frame is mounted to the front of the drive apparatus, and in other embodiments, the frame is mounted to the back of the drive apparatus. Certain embodiments of the cranberry-harvesting apparatus include at least one vacuum nozzle behind the follower assemblies whereby the dislodged cranberries are picked up by vacuum suction. Some embodiments include a vacuum nozzle behind each of the follower assemblies. A collection container may also be included in such apparatus. Broadly considered, the inventive cranberry-harvesting apparatus includes a frame movable over a field of cranberries in a forward direction and a plurality of dislodging rods secured to and below the frame. The dislodging rods are positioned substantially parallel to the field surface and generally perpendicular to the direction of movement such that each dislodging rod is moved through the cranberry plants at the speed of the frame to dislodge the cranberries from the plants. The inventive method for harvesting cranberries from a cranberry field includes moving frame-mounted transverse dislodging rods over cranberry plants with each rod moving at the speed of the frame to dislodge cranberries from the cranberry plants. One form of the inventive method of harvesting cranberries includes moving frame-mounted transverse dislodging rods over cranberry plants in a non-flooded field, thus moving each rod at the speed of the frame to dislodge cranberries from the cranberry plants, resulting in dry-harvesting of the cranberry fruit. Certain preferred embodiments of the inventive method further include the steps of vacuuming up dislodged cranberries immediately after dislodgement and collecting the cranberries in a collection container. As used herein, the following terms have the meanings given below, unless the context requires otherwise. The term “field surface” refers to the surface of the cranberry field from which cranberries are being harvesting. Most typically, this will be the upper surface of a mat of cranberry vines (rather than the surface of the soil) which are being compressed by the follower assemblies as such assemblies are biased downwardly and moved over the cranberry field. The term “surface-following” is used herein to describe one function of the leading end of a follower assembly, indicating that the leading end enables the follower assembly to move over the field surface in a path which conforms to the contour of the field surface without digging into the field surface or becoming entangled with vegetation. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of one embodiment of the inventive cranberry-harvesting apparatus. FIG. 2 is a side elevation of the embodiment shown in FIG. 1. FIG. 3 is top plan view of the embodiment of FIG. 1 with the first-from-the-left of the longer longitudinal arms partially removed to show the overlapping distal ends of neighboring dislodging rods. FIG. 4A is a detailed side elevation of a portion of one embodiment of a rod mount. FIG. 4B is a top plan view of the rod mount shown in FIG. 4A. FIG. 5 is a side elevation of the inventive apparatus, including drive apparatus to pull the frame over the field of cranberries. FIG. 6 is a side elevation of the inventive apparatus, including drive apparatus to push the frame over the field of cranberries. FIG. 7 is a side elevation of the inventive apparatus shown in FIG. 5 further including one vacuum nozzle behind each of the follower assemblies and a collection container. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS FIGS. 1, 2 3, and 5 show a cranberry-harvesting apparatus 10 which is one embodiment of this invention. Apparatus 10 is configured to be pulled over a cranberry field. Apparatus 10 has a frame 20 which is pulled over a cranberry field in the direction indicated in FIG. 1. Apparatus 10 includes ten follower assemblies 22 configured in a forward gang 24 of follower assemblies 22 and a rearward gang 26 of follower assemblies 22. Cranberry-harvesting apparatus 11 of FIG. 6 is configured to be pushed over a cranberry field. This invention is described primarily with reference to apparatus 10; as will be apparent, the two embodiments are substantially similar to each other in their essential elements. Frame 20 consists primarily of a principal cross-member 28. Each follower assembly 22 is attached to frame 20 by a support 30 (ten supports 30 for ten follower assemblies 22). In FIG. 1, five supports 30 are short and five are long, supporting gangs 24 and 26 respectively. Each support 30 includes an anchor arm 36 rigidly connected to principal cross-member 28, a longitudinal arm 32 which is pivotally mounted to anchor arm 36 by a pivot mount 34 located within anchor arm 36 near cross-member 28, a follower mount 48 affixed to longitudinal arm 32, a follower pivot 50 within follower mount 48 spaced away from longitudinal arm 32, and a spring linkage 38. Follower assembly 22 is pivotally connected to follower mount 48 at a point within follower assembly 22 such that the center-of-gravity of follower assembly 22 is forward of follower pivot 50. Anchor arm 36 includes a first connection 40 spaced away from principal cross-member 28. Longitudinal arm 32 includes a second connection 42 also spaced away from cross-member 28. Spring linkage 38 is pivotally connected to first connection 40 and second connection 42 such that longitudinal arm 32 is able to pivot around pivot mount 34 as the contour of the field surface changes. Spring linkage 38 exerts a force such that follower assembly 22 is pushed downwardly onto the field surface. Referring to FIGS. 1 and 2, each follower assembly 22 includes a rod mount 44 which is comprised of a vertical plate 46, four spring posts 62 affixed to plate 46 (plate 46 and posts 62 are a preferably a weldment), a first pair 52 of dislodging rods 60 positioned forward of follower pivot 50 and a second pair 54 of dislodging rods 60 positioned rearward of follower pivot 50. Vertical plate 46 includes a convex surface-following leading end 56 and a lower portion 58. Follower pivot 50 is positioned at lower portion 58, and as noted above, behind the center-of-gravity of follower assembly 22 such that follower assembly 22 moves over the field surface substantially parallel to the field surface. Referring to FIGS. 4A and 4B, each dislodging rod 60 is mounted to vertical plate 46 by one of the spring posts 62 at a proximal end 64 of dislodging rod 60. Dislodging rods 60 typically have a circular cross-section as shown in FIGS. 4A and 4B. Proximal end 64 is formed into a coil spring 65 wrapped around spring post 62, thereby enabling dislodging rods 60 to deflect in a plane substantially parallel to the field surface under the load exerted by the cranberry plants on dislodging rod 60 as follower assembly 22 is moved over the field surface. FIG. 3 is a top plan view of apparatus 10, illustrating the configuration of follower assemblies 22 into forward gang 24 and rearward gang 26. The leftmost follower assembly of rearward gang 26 is partially removed from FIG. 3 to illustrate the relative positions of dislodging rods 60 of neighboring follower assemblies within forward gang 24. Frame 20 has a major axis 70 which is generally perpendicular to the direction of motion of apparatus 10. Each dislodging rod 60 is mounted in an orientation canted at an angle θ with respect to major axis 70 as indicated on the leftmost and forwardmost dislodging rod 60 in FIG. 3. Angle θ is preferably set within the range of 15 to 40 degrees, most preferably about 25 degrees. Each dislodging rod 60 has a distal end 66, and follower assemblies 22 are positioned within gangs 24 and 26 such that distal ends 66 of neighboring follower assemblies 22 overlap an amount sufficient to ensure that all of the cranberry plants are influenced by dislodging rods 60 as apparatus 10 is moved over the field surface even when dislodging rods 60 are deflected backwards under the load of the cranberry plants. Neighboring dislodging rods 60 of adjacent follower assemblies 22 within gangs 24 and 26 are positioned along the direction of motion with a distance d1 between distal ends 66 such that cranberry plants which may become caught up on dislodging rods 60 are shed off distal ends 66 as apparatus 10 moves forward over the field surface. Distance d1 is preferably at least four inches. Each follower assembly 22 has first pair 52 and second pair 54 of dislodging rods 60, first pair 52 being positioned forward of second pair 54 by a distance d2. Distance d2 is preferably at least 12 inches and more typically between 16 and 18 inches. Distance d2 is chosen to be sufficient to allow the cranberry plants which are compressed by first pair 52 to rise up before being compressed again by second pair 54. Distance d2 is therefore dependent on the speed of the forward motion of apparatus 10. High speeds require d2 to be larger. (Distance d, may be about half of distance d2 or may be significantly less as shown in FIG. 3.) The distance between forward gang 24 and rearward gang 26 of follower assemblies 22 is typically larger than distance d2 to ensure that forward gang 24 and rearward gang 26 act on the cranberry plants in an independent fashion. Referring again to FIGS. 4A and 4B, each rod mount 44 further includes two feet 68 which extend rearwardly from lower portion 58 of vertical plate 46 below first pair 52 and second pair 54. The function of feet 68 is to prevent the entanglement of cranberry plants in spring posts 62 and coil springs 65 as apparatus 10 moves over the field surface. Each foot 68 has a tapered front portion 72 to ease movement through the cranberry plants and an open rear portion 74 to release entangled plants. FIGS. 5 and 6 are side elevations simply illustrating the fact that the inventive cranberry-harvesting apparatus can be both pulled (FIG. 5) and pushed (FIG. 6) over the field surface by a drive apparatus 80, typically a farm tractor suitably configured to drive over a cranberry field. Illustrated in both FIGS. 5 and 6, the harvesting apparatus is attached to drive apparatus 80 on a movable hitch 82. Movable hitch 82 is the standard movable hitch typically available on farm tractors to raise and lower farm implements for proper operation. In addition, frame 20 is able to be rotated on hitch 82 by hydraulic actuator 84 acting on frame arm 86, further enabling the height and orientation of apparatus 10 and 11 to be adjusted for proper operation. For example, in apparatus 11 in FIG. 6, follower assemblies 22 are mounted in the opposite direction from that of apparatus 10 with respect to frame 20 and supports 30. FIG. 7 is a side elevation of the embodiment of FIG. 5 configured for dry harvesting of cranberries. Each follower assembly 22 has mounted immediately behind it a vacuum nozzle 88 connected to vacuum unit 90. Cranberries which are picked up by vacuum unit 90 through vacuum nozzles 88 are deposited into collection container 92. The general operation of the apparatus 10 is as follows. Apparatus 10 is lowered down onto the field surface such that follower assemblies 22, primarily through dislodging rods 60, compress the cranberry plants from an uncompressed thickness, which is typically on the order of twelve inches, down to a thickness of a few inches. Apparatus 10 is moved forward over the field surface, thereby moving dislodging rods 60 over the field surface at the speed of apparatus 10. As dislodging rods 60 compress the cranberry plants, the cranberry fruit is dislodged from the cranberry plants with a minimum of damage to both fruit and vines. One mechanism by which this dislodging takes place is a squeegee-like action on the field surface. Except those areas covered by the left and right sides of apparatus 10, every point along the field surface is in general acted on by four dislodging rods 60, thereby providing significant opportunity for the cranberry fruit to be released from the cranberry plants. Typically, apparatus 10 is moved forward over the field surface by drive apparatus 80 at speeds of five or six miles per hour, thereby being able to harvest approximately three acres of cranberries per hour. High-speed harvesting using the inventive apparatus may be carried out in flooded cranberry bogs, with subsequent cranberry recovery carried out using standard methods known in the art for the gathering of floating berries. Apparatus 10 is able also to be used for dry harvesting of cranberries such that at least a substantial portion of the crop is harvested without being wetted. During dry harvesting, vacuum nozzles 88 mounted immediately behind follower assemblies 22, are used to pick up the cranberries which have been dislodged by dislodging rods 60. Since some of the dislodged cranberries may be trapped within the cranberry plants during dislodgment and vacuuming, the cranberry field may then be flooded and the typical methods for the gathering of dislodged cranberries in flooded fields used to complete the harvest. While the principles of this invention have been described in connection with specific embodiments, it should be understood clearly that these descriptions are made only by way of example and are not intended to limit the scope of the invention. | <SOH> BACKGROUND OF THE INVENTION <EOH>Cranberries are raised in fields or bogs, which are relatively flat areas divided into sections so that the fields can be flooded both to facilitate harvesting and to protect the vines from frost. The cranberry plants form a mat of vines which may be up to twelve or fourteen inches deep. During harvesting, the berries are removed from the vines and float to the surface of the water. The berries are then gathered up for transport to a processing facility. Traditional methods of harvesting cranberries and the equipment used to implement such methods generally fall into two categories. Both traditional methods have drawbacks which will be described herein later. The first general method can be characterized as “beating” and is carried out using equipment which includes beaters which are bars mounted on combine-like revolving structures. U.S. Pat. No. 3,672,140 (Burford) discloses equipment based on this principal. As the harvesting vehicle moves through the cranberry bog, a rotating wheel with transverse bars to agitate the cranberry vines, causes the cranberries to detach from the plants. The rotation of the wheel causes the transverse bars to move through the cranberry vines at a speed greater than the vehicle speed at the position of principal contact with the plants. Cranberries float to the surface of the flooded bog and are gathered up. U.S. Pat. No. 4,501,111 issued to Abbott describes another harvester unit which uses such a rotating wheel approach. The second general method can be characterized as picking or raking. U.S. Pat. No. 2,524,631 (Minutillo) describes a harvesting machine based on this method. A series of combs mounted on a rotating wheel is moved through the cranberry plants to detach the cranberries from the vines. U.S. Pat. No. 5,067,047 (Rosset) discloses harvesting equipment which employs vertically-oscillating tines to strip the cranberries from the vines. Rosset then collects the stripped cranberries through a vacuum suction unit. As mentioned above, the methods and equipment which are used for cranberry harvesting have certain drawbacks. As in any commercial endeavor, increased productivity is in general a desired performance. Typical harvesting rates for the cranberry-harvesting equipment commonly used today is on the order of 0.5 acres per hour, with maximum rates being about 1.5 acres per hour. Productivity is also affected by the fraction of the fruit which is removed from the vines during harvesting. A higher fraction yields higher productivity. Some of this equipment is quite “aggressive” in how it treats the cranberry plants, often resulting in damage both to harvested fruit as well as the vines. In addition, much of the equipment used today includes a number of moving parts, often driven by hydraulic equipment. The operation of hydraulic equipment during harvesting creates the risk of the fruit becoming contaminated with hydraulic fluid. Also, the complexity of the equipment translates into increased maintenance cost. Finally, for cranberries which are sold as fresh fruit rather than processed into juice or other consumer food products, not only is it advantageous to prevent damage to the fruit, it is also of great benefit to avoid wetting the fruit during harvesting. As mentioned above, the fields or bogs are flooded, allowing the fruit which has been separated from the plants to float, thereby facilitating the collection of the fruit. However, the fruit, being now wet, is subject to the growth of fungus or requires the additional costly step of drying in order to deliver fresh, unblemished fruit to the market. Because of this, it is advantageous to dry-harvest cranberries to avoid these problems or costs. Therefore, there is a need for simple, rapid and efficient, low-cost method and apparatus to harvest cranberries. | <SOH> SUMMARY OF THE INVENTION <EOH>The invention is a method and apparatus for harvesting cranberries, whereby frame-mounted transverse dislodging rods are moved over cranberry plants with each rod moving at the speed of the frame, thereby dislodging cranberries from the cranberry plants. The cranberry-harvesting apparatus of this invention comprises a frame movable over a field of cranberries in a forward direction with a plurality of follower assemblies each secured to and below the frame by a support. Each follower assembly includes: a rod mount having a lower portion, a surface-following leading end, and a pivot attachment to the support at the lower portion behind the center-of-gravity of the follower assembly; and first and second pairs of dislodging rods mounted to the rod mount forward and rearward of the pivot attachment respectively, each pair extending laterally from opposite sides of the lower portion substantially parallel to the field surface and canted rearwardly. Each rod mount is supported such that it moves through the cranberry plants at the speed of the frame to dislodge the cranberries from the plants. In certain highly preferred embodiments of the inventive cranberry-harvesting apparatus, the first and second pairs of dislodging rods are spring-mounted such that the dislodging rods deflect under load in a plane substantially parallel to the field surface. In another preferred embodiment of the cranberry-harvesting apparatus, each rod mount is a vertical plate having spring posts extending downward to the lower portion, and each dislodging rod has a coiled proximal end forming a spring coiled around one of the spring posts. Certain preferred embodiments of such apparatus further include feet extending from the lower portion rearwardly below each pair of spring posts for the purpose of reducing the entanglement of plants with the spring posts. In another preferred embodiment of the apparatus, the dislodging rods have a substantially circular cross-section. In highly preferred embodiments of the cranberry-harvesting apparatus, the frame has a major axis generally perpendicular to the movement thereof and parallel to the field surface. Each dislodging rod has a free distal end, and the follower assemblies are laterally spaced substantially equally along the major axis in alternating forward and rearward positions thereby forming offset forward and rearward gangs of adjacent assemblies such that the distal ends of the dislodging rods of adjacent assemblies overlap along the major axis. The distal ends of the dislodging rods of adjacent assemblies of each gang are spaced apart along the direction of movement. In certain other embodiments of the inventive cranberry-harvesting apparatus, the space along the direction of movement between the dislodging rod distal ends of adjacent follower assemblies is at least four inches. In highly-preferred embodiments of the cranberry-harvesting apparatus, the frame includes a principal cross-member, and each support includes a longitudinal arm pivotably mounted to the cross-member. In some embodiments of the cranberry-harvesting apparatus, each longitudinal arm is downwardly spring-biased against the field surface. In such embodiments, it is most preferred that such apparatus include: an anchor arm affixed to the cross-member and having a first connection spaced therefrom; a second connection on the longitudinal arm spaced from the cross-member; and a spring linkage between the first and second connections such that the longitudinal arm moves under load with respect to the anchor arm to provide the downward biasing. In some embodiments, each surface-following leading end is substantially convex. In other embodiments of the cranberry-harvesting apparatus, the frame is operator-movable up and down such that the surface-following leading ends can be positioned in and out of contact with the field surface. In another preferred embodiment of the inventive apparatus, the space between the first and second pairs of dislodging rods is at least twelve inches. In addition, in some preferred embodiments, the cant angle of the dislodging rods is between 15 and 40 degrees from the major axis. Some highly-preferred embodiments of the invention further include a drive apparatus to move the frame over a field of cranberries. In some embodiments, the frame is mounted to the front of the drive apparatus, and in other embodiments, the frame is mounted to the back of the drive apparatus. Certain embodiments of the cranberry-harvesting apparatus include at least one vacuum nozzle behind the follower assemblies whereby the dislodged cranberries are picked up by vacuum suction. Some embodiments include a vacuum nozzle behind each of the follower assemblies. A collection container may also be included in such apparatus. Broadly considered, the inventive cranberry-harvesting apparatus includes a frame movable over a field of cranberries in a forward direction and a plurality of dislodging rods secured to and below the frame. The dislodging rods are positioned substantially parallel to the field surface and generally perpendicular to the direction of movement such that each dislodging rod is moved through the cranberry plants at the speed of the frame to dislodge the cranberries from the plants. The inventive method for harvesting cranberries from a cranberry field includes moving frame-mounted transverse dislodging rods over cranberry plants with each rod moving at the speed of the frame to dislodge cranberries from the cranberry plants. One form of the inventive method of harvesting cranberries includes moving frame-mounted transverse dislodging rods over cranberry plants in a non-flooded field, thus moving each rod at the speed of the frame to dislodge cranberries from the cranberry plants, resulting in dry-harvesting of the cranberry fruit. Certain preferred embodiments of the inventive method further include the steps of vacuuming up dislodged cranberries immediately after dislodgement and collecting the cranberries in a collection container. As used herein, the following terms have the meanings given below, unless the context requires otherwise. The term “field surface” refers to the surface of the cranberry field from which cranberries are being harvesting. Most typically, this will be the upper surface of a mat of cranberry vines (rather than the surface of the soil) which are being compressed by the follower assemblies as such assemblies are biased downwardly and moved over the cranberry field. The term “surface-following” is used herein to describe one function of the leading end of a follower assembly, indicating that the leading end enables the follower assembly to move over the field surface in a path which conforms to the contour of the field surface without digging into the field surface or becoming entangled with vegetation. | 20040120 | 20061017 | 20050721 | 73619.0 | 1 | PETRAVICK, MEREDITH C | CRANBERRY-HARVESTING APPARATUS AND METHOD | SMALL | 0 | ACCEPTED | 2,004 |
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10,760,805 | ACCEPTED | Methods and apparatus for operating gas turbine engines | A method of assembling a gas turbine engine includes coupling an annular exhaust duct to the gas turbine engine, coupling a plurality of chevrons to the annular exhaust duct, and coupling a chevron actuation system to the annular exhaust duct such that selective operation of the chevron actuation system repositions the plurality of chevrons to adjust an amount convergence of the annular exhaust duct. | 1. A method of assembling a gas turbine engine, said method comprising: coupling an annular exhaust duct to the gas turbine engine; coupling a plurality of chevrons to the annular exhaust duct; and coupling a chevron actuation system to the annular exhaust duct such that selective operation of the chevron actuation system repositions the plurality of chevrons to adjust an amount convergence of said annular exhaust duct. 2. A method in accordance with claim 1 wherein coupling a chevron actuation system to the annular exhaust duct further comprises coupling a chevron actuation system that is fabricated at least partially from a shape memory alloy to the annular exhaust duct. 3. A method in accordance with claim 1 wherein coupling a chevron actuation system to the annular exhaust duct further comprises coupling a chevron actuation system that is operable in at least one of a passive mode and an active mode to the annular exhaust duct. 4. A method in accordance with claim 3 wherein operating in the passive mode comprises using engine exhaust nozzle heat to activate the shape memory alloy and thereby increase a convergence of the annular exhaust duct. 5. A method in accordance with claim 3 wherein operating in the active mode comprises using electricity to activate the shape memory alloy and thereby increase a convergence of the annular exhaust duct. 6. A method in accordance with claim 1 wherein coupling a chevron actuation system to the annular exhaust duct further comprises coupling a band fabricated from a shape memory alloy around an outer periphery of the annular exhaust duct. 7. A method in accordance with claim 1 wherein coupling a chevron actuation system to the annular exhaust duct further comprises coupling a chevron actuation system including a plurality of mounting portions and at least one finger coupled to each mounting portion to an outer surface of the annular exhaust duct such that at least one finger extends along an outer surface of each chevron. 8. A method of operating a gas turbine engine that includes an annular exhaust duct and a plurality of chevrons coupled to the annular exhaust duct, said method comprising: coupling a chevron actuation system to the annular exhaust duct wherein at least a portion of the chevron actuation system is fabricated from a shape memory alloy that has a memorized activation configuration and such that the plurality of chevrons are oriented in a first configuration; and heating the shape memory alloy such that the plurality of chevrons are reconfigured from the first configuration to an activation configuration. 9. A method in accordance with claim 8 wherein coupling a chevron actuation system to the annular exhaust duct comprises coupling a chevron actuation system to at least one of a turbine engine exhaust duct and a fan exhaust duct. 10. A method in accordance with claim 8 wherein coupling a chevron actuation system to the annular exhaust duct comprises coupling a band fabricated from a shape memory alloy to the annular exhaust duct, wherein the band has a first length at a first temperature and has a second length at a second temperature, wherein the first length is longer than the second length and the first temperature is less than the second temperature. 11. A method in accordance with claim 8 wherein coupling a chevron actuation system to the annular exhaust duct further comprises coupling a chevron actuation system that is fabricated from a shape memory alloy to the annular exhaust duct, wherein the shape memory alloy is transformable from a martensitic state to an austenitic state, and wherein the actuator is restorable from an initial configuration to a memorized configuration at an operating temperature which causes the shape memory alloy to transform to the austenitic state. 12. A method in accordance with claim 8 wherein coupling a chevron actuation system to the annular exhaust duct comprises coupling a chevron actuation system fabricated from at least one of an alloy of nickel and titanium, and an alloy of nickel and ruthenium, to the annular exhaust duct. 13. A gas turbine engine comprising: an annular exhaust duct comprising an aft end, said annular exhaust duct for discharging exhaust from an aft end of said gas turbine engine; a plurality of circumferentially adjoining chevrons extending from said duct aft end; and a chevron actuation system coupled to said annular exhaust duct for controlling relative movement of said plurality of chevrons, a portion of said chevron actuation system is fabricated from a shape memory alloy material. 14. A gas turbine engine in accordance with claim 13 wherein said annular exhaust duct comprises at least one of an core engine exhaust duct and a fan exhaust duct. 15. A gas turbine engine in accordance with claim 13 wherein said chevron actuation system comprises a shape memory alloy band coupled to an outer periphery of said annular exhaust duct. 16. A gas turbine engine in accordance with claim 13 wherein said chevron actuation system comprises a plurality of actuators, each said actuator comprising a mounting portion and at least one finger coupled to said mounting portion, each said at least one finger coupled to an outer surface of said annular exhaust duct such that each said at least one finger extends along an outer surface of each said chevron. 17. A gas turbine engine in accordance with claim 16 wherein said at least one finger is fabricated from a shape memory alloy material. 18. A gas turbine engine in accordance with claim 13 wherein at least a portion of said chevron actuation system comprises at least one of an alloy of nickel and titanium, and an alloy of nickel and ruthenium. 19. A gas turbine engine in accordance with claim 13 wherein said shape memory alloy is transformable from a martensitic state to an austenitic state, and wherein said actuator is restorable from an initial configuration to a memorized configuration at an operating temperature that causes the shape memory alloy to transform to the austenitic state. 20. A gas turbine engine in accordance with claim 13 wherein said shape memory alloy is configured to reposition said plurality of chevrons radially inwardly towards a gas turbine centerline axis when activated. 21. A gas turbine engine comprising: an annular exhaust duct comprising an aft end, said annular exhaust duct for discharging exhaust from an aft end of said gas turbine engine; and a plurality of circumferentially adjoining chevrons extending from said duct aft end, said plurality of circumferentially adjoining chevrons fabricated from a shape memory alloy material. 22. A gas turbine engine in accordance with claim 21 wherein said annular exhaust duct comprises at least one of an core engine exhaust duct and a fan exhaust duct. | BACKGROUND OF THE INVENTION This invention relates generally to gas turbine engines, more particularly to methods and apparatus for operating gas turbine engines. At least some known gas turbine engines include a core engine having, in serial flow arrangement, a fan assembly and a high pressure compressor which compress airflow entering the engine, a combustor which burns a mixture of fuel and air, and low and high pressure rotary assemblies which each include a plurality of rotor blades that extract rotational energy from airflow exiting the combustor. Combustion gases are discharged from the core engine through an exhaust assembly. More specifically, within at least some known turbofan engines, a core exhaust nozzle discharges core exhaust gases radially inwardly from a concentric fan exhaust nozzle which exhausts fan discharge air therefrom for producing thrust. Typically, both exhaust flows have a maximum velocity when the engine is operated during high power operations, such as during take-off operations. During such operations, as the high velocity flows interact with each other and with ambient air flowing past the engine, substantial noise may be produced along the take-off path of the aircraft. To facilitate reducing jet noise, at least some known turbine engine exhaust assemblies include a plurality of chevron nozzles to enhance mixing the core and bypass exhaust flows. Although the chevron nozzles do provide a noise benefit during take-off conditions, because the nozzles are mechanical devices which remain positioned in the flow path during all flight conditions, such devices may adversely impact engine performance during non-take-off operating conditions. Specifically, during cruise conditions, chevron nozzles may adversely impact specific fuel consumption (SFC) of the engine. BRIEF DESCRIPTION OF THE INVENTION In one aspect, a method of assembling a gas turbine engine is provided. The method includes coupling an annular exhaust duct to the gas turbine engine, coupling a chevron actuation system to the annular exhaust duct such that selective operation of the chevron actuation system repositions the plurality of chevrons to adjust an amount convergence of the annular exhaust duct. In another aspect a method of operating a gas turbine engine that includes an annular exhaust duct and a plurality of chevrons coupled to the annular exhaust duct is provided. The method includes coupling a chevron actuation system to the annular exhaust duct wherein at least a portion of the chevron actuation system is fabricated from a shape memory alloy that has a memorized activation configuration and such that the plurality of chevrons are oriented in a first configuration during engine operation, and passively or actively heating the shape memory alloy such that the plurality of chevrons are reconfigured from the first configuration to an activation configuration. In a further aspect, a gas turbine engine is provided. The gas turbine engine includes an annular exhaust duct for discharging exhaust from an aft end thereof, a plurality of circumferentially adjoining chevrons extending from the duct aft end, and a chevron actuation system coupled to the annular exhaust duct, a portion of the chevron actuation system fabricated from a shape memory alloy material. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic illustration of a gas turbine engine; FIG. 2 is a side view of an exemplary nozzle that may be used with the gas turbine engine shown in FIG. 1; FIG. 3 is a perspective view of an exemplary chevron actuation system that may be used with the nozzle shown in FIG. 2; and FIG. 4 is a perspective view of an exemplary chevron actuation system that may be used with the nozzle shown in FIG. 2. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 is a perspective view of a turbofan aircraft gas turbine engine 10 coupled to a wing of an aircraft 12 using a pylon 14, for example. Engine 10 includes a core engine exhaust nozzle 16 and a fan exhaust nozzle 18 which discharge combustion gas exhaust 20 and pressurized fan air exhaust 22, respectively. Engine 10 also includes a fan 24 having at least one row of rotor blades mounted inside a corresponding fan nacelle at a forward end of engine 10. Fan 24 is driven by a core engine 26 which is mounted concentrically inside the fan nacelle along an axial or centerline axis 28. Core engine 26 includes a high pressure turbine (not shown) coupled to a compressor (not shown) which extracts energy from the combustion gases for powering the compressor. A low pressure turbine (not shown) is disposed downstream from the high pressure turbine and is coupled to fan 24 by a shaft (not shown) that is rotated by extracting additional energy from the combustion gases which are discharged as combustion gas exhaust 20 from core engine exhaust nozzle 16. An annular centerbody 30 is spaced radially inwardly from core engine exhaust nozzle 16 and converging in the aft direction downstream therefrom. Core engine exhaust nozzle 16 and fan exhaust nozzle 18 each include an annular exhaust duct 32. In the exemplary embodiment, each annular exhaust duct 32 is a one-piece or substantially unitary ring positioned concentrically around centerline axis 28. In an alternative embodiment, engine 10 includes, but is not limited to, at least one of an internal plug nozzle, a long duct mixed flow nozzle, and a convergent/divergent (CD) variable area nozzle. A plurality of circumferentially adjoining chevrons 34 extend axially aft from an aft end of annular exhaust duct 32 preferably in a unitary and coextensive configuration therewith. During operation, to produce thrust from engine 10, fan discharge flow is discharged through fan exhaust nozzle 18, and combustion gases are discharged from engine 10 through core engine exhaust nozzle 16. In one embodiment, engine 10 is operated at a relatively high bypass ratio which is indicative of the amount of fan air which bypasses engine 10 and is discharged through fan exhaust nozzle 18. In an alternative embodiment, engine 10 is operable with a low bypass ratio. FIG. 2 is a side view of an exemplary nozzle 50 that can be used with gas turbine engine 10, (shown in FIG. 1) in a first operational configuration. FIG. 3 is a side view of nozzle 50 in a second operational configuration. Nozzle 50 is substantially similar to core engine exhaust nozzle 16 and fan nozzle exhaust 18, (shown in FIG. 1) and components in nozzle system 50 that are identical to components of core engine exhaust nozzle 16 and fan nozzle exhaust 18 are identified in FIG. 2 and FIG. 3 using the same reference numerals used in FIG. 1. Accordingly, in one embodiment, nozzle 50 is a core engine exhaust nozzle. In another embodiment, nozzle 50 is a fan nozzle. Nozzle 50 includes a plurality of circumferentially or laterally adjoining chevrons 52 integrally disposed at an aft end 54 of annular exhaust duct 32. Each chevron 52 has a geometric shape 56. In the exemplary embodiment, each chevron 52 has a substantially triangular shape and includes a base 58 fixedly coupled or integrally joined to annular exhaust duct 32. Each chevron 52 also includes an axially opposite apex 60, and a pair of circumferentially or laterally opposite trailing edges 62 or sides converging from base 58 to each respective apex 60 in the downstream, aft direction. Each chevron 52 also includes a radially outer surface 63, and a radially opposite inner surface 64 bounded by trailing edges 62 and base 58. Trailing edges 62 of adjacent chevrons 52 are spaced circumferentially or laterally apart from the bases 58 to apexes 60 to define respective slots or cut-outs 65 diverging laterally and axially, and disposed in flow communication with the inside of annular exhaust duct 32 for channeling flow radially therethrough. In the exemplary embodiment, slots 65 are also triangular and complementary with triangular chevrons 52 and diverge axially aft from a slot base 66, which is circumferentially coextensive with chevrons bases 58, to chevron apexes 60. In one exemplary embodiment, each chevron outer surface 63 is disposed approximately parallel to centerline axis 28 to form a diverging exhaust nozzle as shown in FIG. 2. Moreover, as shown in FIG. 3, each chevron outer surface 63 can be re-positioned to adjust an amount convergence of the annular exhaust duct. Accordingly, repositioning each chevron 52 facilitates mixing effectiveness while at the same time providing an aerodynamically smooth and non-disruptive profile for minimizing losses in aerodynamic efficiency and performance. FIG. 4 is a perspective view of an exemplary chevron actuation system 70 that can be used with nozzle 50 (shown in FIGS. 2 and 3). Chevron actuation system 70 includes an actuator or shape memory alloy band 72 coupled to annular exhaust duct 32. In the exemplary embodiment, actuator 72 is positioned forward of chevrons 52 and circumferentially around an outer periphery 76 of annular exhaust duct 32. In the exemplary embodiment, single actuator 72 is fabricated from a shape memory alloy 74 having a memorized activated configuration. Shape memory alloy 74 is used to reposition chevrons 52 and thereby either increase or decrease the convergence of annular exhaust duct 32. As used herein a shape memory alloy is defined as a material which can be formed into any desired shape. Various metallic materials are capable of exhibiting shape-memory characteristics. These shape-memory capabilities occur as the result of the metallic alloy undergoing a reversible crystalline phase transformation from one crystalline state to another crystalline state with a change in temperature and/or external stress. In particular, alloys of nickel and titanium exhibit these properties of being able to undergo energetic crystalline phase changes at ambient temperatures, thus giving them a shape-memory. These shape-memory alloy materials, if plastically deformed while cool, will revert to their original, undeformed shape when warmed. These energetic phase transformation properties render articles made from these alloys highly useful in a variety of applications. For example, the shape “training” of SMA's is accomplished by holding the SMA into their desired shape and then heating and holding to a higher temperature. Upon cooling, the SMA will retain the desired shape. When the SMA is mechanically deformed at a lower temperature, the SMA will revert to its “trained shape” upon subsequent heating. An article made of an alloy having shape-memory properties can be deformed at a low temperature from its original configuration, but the article “remembers” its original shape, and returns to that shape when heated. More specifically, and in the exemplary embodiment, For example, in nickel-titanium alloys possessing shape-memory characteristics, the alloy undergoes a reversible transformation from an austenitic state to a martensitic state with a change in temperature. This transformation is often referred to as a thermoelastic martensitic transformation. The reversible transformation of the NiTi alloy between the austenite to the martensite phases occurs over two different temperature ranges which are characteristic of the specific alloy. As the alloy cools, it reaches a temperature Ms at which the martensite phase starts to form, and finishes the transformation at a still lower temperature Mf. Upon reheating, it reaches a temperature As at which austenite begins to reform and then a temperature Af at which the change back to austenite is complete. In the martensitic state, the alloy can be easily deformed. When sufficient heat is applied to the deformed alloy, it reverts back to the austenitic state, and returns to its original configuration. Accordingly, in the exemplary embodiment actuator 72 is fabricated from a material such as, but not limited to, NiTi, NiTi—Pt, TiRu, NiTiCu, CuZnAl, CuAlNi, NiTiFe, CuAlNiTiMn, TiNiPd, TiNiPt, NiTiPd, and TiNiHf. In the exemplary embodiment, the lower temperature chevrons used for the fan chevrons are fabricated from a Ni—Ti alloy, and the higher temperature chevrons used for the core engine chevrons are fabricated from a Ni—Ti—Pt alloy. During operation, chevron actuation system 70 is operable in at least one of an active mode and a passive mode. In the active mode, an electrical current is input to actuator 72, i.e. shape memory alloy 74, such that actuator 72 is contracted around outer periphery 76 of annular exhaust duct 32. Contracting actuator 72 causes shape memory alloy band 72 to reconfigure from a first length 77 to a second length 78, shorter than first length 77, thus causing plurality of chevrons 52 to deflect inwardly toward central axis 28 (shown in FIG. 3). More specifically, shape memory alloy band 72 contracts around outer periphery 76 such that a convergence of nozzle 50 is increased. When actuator 72 is de-energized, plurality of chevrons 52 deflect outwardly from central axis 28 such that plurality of chevrons 52 are substantially parallel to outer periphery 76 of annular exhaust duct 32, thus decreasing the convergence of nozzle 50 (shown in FIG. 4). In the passive mode, heat is input to actuator 72, i.e. shape memory alloy 74, such that actuator 72 is contracted around outer periphery 76 of annular exhaust duct 32. In the exemplary embodiment, heat is supplied from engine 10 during takeoff or landing, for example. More specifically, engine exhaust flow, during operations other than take-off, flows past chevrons 52 but does not result in activation of actuator 72 since the temperature of the exhaust is not great enough to activate shape memory alloy 74. During take-off operations, engine exhaust flow, having an increased temperature, flows past chevrons 52 and actuates shape memory alloy 74 resulting in an increased convergence of exhaust nozzle 50. When the airplane has reached a cruise condition, the temperature of the exhaust flow is reduced, resulting in chevrons 52 deflecting away from central axis 28, such that a convergence of nozzle 50 is decreased. FIG. 5 is a perspective view of an exemplary chevron actuation system 80 that can be used with nozzle 50 (shown in FIGS. 2 and 3). Chevron actuation system 80 includes a plurality of actuators 82 coupled to annular exhaust duct 32. In the exemplary embodiment, each actuator 82 includes a mounting portion 84 and a finger 86 coupled to mounting portion 84 and extending along outer surface 63 of each chevron 52. In the exemplary embodiment, a plurality of fingers 86 are positioned along outer surface 63 of each chevron 52 and circumferentially around outer perimeter 76 of annular exhaust duct 32. In the exemplary embodiment, fingers 86 are fabricated from shape memory alloy 74 having a memorized activated configuration. In the exemplary embodiment, shape memory alloy 74 is activated to reposition chevrons 52 and thereby either increase or decrease a convergence of the nozzle. As used herein a shape memory alloy is defined as a material which can be formed into any desired shape as described previously herein. Accordingly, in the exemplary embodiment actuator fingers 86 are fabricated from material such as, but not limited to, NiTi, TiRu, NiTiCu, CuZnAl, CuAlNi, NiTiFe, CuAlNiTiMn, TiNiPd, TiNiPt, NiTiPd, and TiNiHf. During operation, chevron actuation system 80 is operable in at least one of an active mode and a passive mode. In the active mode, an electrical current is input to each finger 86, i.e. shape memory alloy 74, such that each finger 86 is contracted around outer periphery 76 of annular exhaust duct 32. Contracting fingers 86 causes plurality of chevrons 52 to deflect inwardly toward central axis 28 (shown in FIG. 3). Accordingly, actuating fingers 86 increases a convergence of nozzle 50. When fingers 86 are de-energized, plurality of chevrons 52 deflect outwardly from central axis 28 such that plurality of chevrons 52 are substantially parallel to outer periphery 76 of annular exhaust duct 32, thus decreasing the convergence of nozzle 50 (shown in FIG. 5). In the passive mode, heat is applied to fingers 86 to activate shape memory alloy 74. In the exemplary embodiment, heat is supplied from the engine during engine takeoff or landing, for example. More specifically, engine exhaust flow, during operations other than take-off, flows past chevrons 52 but does not result in activation of fingers 86 since the temperature of the exhaust is not great enough to activate shape memory alloy 74. During take-off operations, engine exhaust flow, having an increased temperature, flows past chevrons 52 and actuates shape memory alloy 74 thereby increasing a convergence of exhaust nozzle 50 (shown in FIG. 3). When the airplane has reached a cruise condition, the temperature of the exhaust flow is reduced, resulting in chevrons 52 deflecting away from central axis 28, such that a convergence of nozzle 50 is decreased (shown in FIG. 5). In another exemplary embodiment, nozzle 50 includes a plurality of circumferentially or laterally adjoining chevrons 52 integrally disposed at an aft end 54 of annular exhaust duct 32. Each chevron 52 has a geometric shape 56. In the exemplary embodiment, each chevron 52 has a substantially triangular shape and is fabricated from a shape memory alloy material. Additionally, the shape metal alloy chevrons may be operated in either a passive or active mode as described previously herein. Accordingly, fabricating each chevron from a shape memory alloy material facilitates reducing a quantity of parts used to fabricate nozzle 50 and thereby facilitates reducing the time required to fabricate the nozzle. The above-described nozzle exhaust system includes a plurality of chevrons which can be repositioned to either increase a convergence of the exhaust nozzle during takeoff or decrease a convergence of the exhaust nozzle during cruise conditions using a shape memory alloy. The shape memory alloy is selectably operable using either electrical current supplied to the shape memory alloy or using engine exhaust heat. According, the shape memory alloy reconfigures the exhaust nozzle chevrons only when required, during takeoff for example, and streamlines the exhaust nozzle chevrons when not required, during cruise conditions for example. Accordingly, the nozzle system described herein facilitates reducing noise during takeoff or landing, and reducing or eliminating engine performance losses during cruise conditions. Exemplary embodiments of noise suppression systems and exhaust assemblies are described above in detail. The exhaust assemblies are not limited to the specific embodiments described herein, but rather, components of each assembly may be utilized independently and separately from other components described herein. For example, each noise suppression component can also be used in combination with other exhaust assemblies. While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>This invention relates generally to gas turbine engines, more particularly to methods and apparatus for operating gas turbine engines. At least some known gas turbine engines include a core engine having, in serial flow arrangement, a fan assembly and a high pressure compressor which compress airflow entering the engine, a combustor which burns a mixture of fuel and air, and low and high pressure rotary assemblies which each include a plurality of rotor blades that extract rotational energy from airflow exiting the combustor. Combustion gases are discharged from the core engine through an exhaust assembly. More specifically, within at least some known turbofan engines, a core exhaust nozzle discharges core exhaust gases radially inwardly from a concentric fan exhaust nozzle which exhausts fan discharge air therefrom for producing thrust. Typically, both exhaust flows have a maximum velocity when the engine is operated during high power operations, such as during take-off operations. During such operations, as the high velocity flows interact with each other and with ambient air flowing past the engine, substantial noise may be produced along the take-off path of the aircraft. To facilitate reducing jet noise, at least some known turbine engine exhaust assemblies include a plurality of chevron nozzles to enhance mixing the core and bypass exhaust flows. Although the chevron nozzles do provide a noise benefit during take-off conditions, because the nozzles are mechanical devices which remain positioned in the flow path during all flight conditions, such devices may adversely impact engine performance during non-take-off operating conditions. Specifically, during cruise conditions, chevron nozzles may adversely impact specific fuel consumption (SFC) of the engine. | <SOH> BRIEF DESCRIPTION OF THE INVENTION <EOH>In one aspect, a method of assembling a gas turbine engine is provided. The method includes coupling an annular exhaust duct to the gas turbine engine, coupling a chevron actuation system to the annular exhaust duct such that selective operation of the chevron actuation system repositions the plurality of chevrons to adjust an amount convergence of the annular exhaust duct. In another aspect a method of operating a gas turbine engine that includes an annular exhaust duct and a plurality of chevrons coupled to the annular exhaust duct is provided. The method includes coupling a chevron actuation system to the annular exhaust duct wherein at least a portion of the chevron actuation system is fabricated from a shape memory alloy that has a memorized activation configuration and such that the plurality of chevrons are oriented in a first configuration during engine operation, and passively or actively heating the shape memory alloy such that the plurality of chevrons are reconfigured from the first configuration to an activation configuration. In a further aspect, a gas turbine engine is provided. The gas turbine engine includes an annular exhaust duct for discharging exhaust from an aft end thereof, a plurality of circumferentially adjoining chevrons extending from the duct aft end, and a chevron actuation system coupled to the annular exhaust duct, a portion of the chevron actuation system fabricated from a shape memory alloy material. | 20040120 | 20060822 | 20050721 | 68473.0 | 0 | CASAREGOLA, LOUIS J | METHODS AND APPARATUS FOR OPERATING GAS TURBINE ENGINES | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,760,920 | ACCEPTED | Moisture curable sealer and adhesive composition | A low cost moisture curable sealer and adhesive composition containing a polymer having reactive silyl groups and a bituminous material and having many advantages over conventional moisture cure sealer compositions, including greater elastomeric properties, improved flexibility and pliability, lower durometer, faster and deeper cure, low temperature cure. The composition is also free of carcinogens such as coal tar, toxic isocyanates, and volatile solvents. | 1. A moisture curable composition, comprising: a polymer having reactive silyl groups; and a bituminous material. 2. A moisture curable adhesive composition, comprising: a polymer having reactive silyl groups; and a bituminous material 3. The moisture curable composition of claim 1, wherein the polymer having reactive silyl groups is a polyacrylate having reactive silyl groups, a polyether having reactive silyl groups, or a polyurethane having reactive silyl groups. 4. The moisture curable composition of claim 1, wherein the polymer having reactive silyl groups is an α, ω-telechelic silyl-terminated polymer. 5. The moisture curable composition of claim 1, wherein the polymer having reactive silyl groups is a silyl-terminated oxyalkylene polymer. 6. The moisture curable composition of claim 1, wherein the bituminous material is asphalt. 7. The moisture curable composition of claim 1, further comprising a compatabilizing plasticizer in an amount effective to wet and help disperse the bituminous material in the polymer having reactive silyl groups. 8. The moisture curable composition of claim 6, wherein the compatibilizer is an ester of a polyol with a fatty acid, the condensation product of a polycarboxylic acid and an alkanol, or a polyester polyol having repeating units derived from acrylic or methacrylic acid and a polyol. 9. The moisture curable composition of claim 1, further comprising a catalyst for promoting fast reaction among the reactive silyl groups of the polymer having reactive silyl groups. 10. The moisture curable composition of claim 1, wherein the bituminous material is present in an amount of from about 20 to about 175 parts by weight per 100 parts by weight of the polymer having reactive silyl groups. 11. The moisture curable composition of claim 1, wherein the bituminous material is present in an amount of from about 75 to about 150 parts by weight per 100 parts by weight of the polymer having reactive silyl groups. 12. The moisture curable composition of claim 1, wherein the composition is substantially free of volatile organic compounds. 13. The moisture curable composition of claim 1, wherein the composition is substantially free of isocyanate groups. 14. A moisture curable composition consisting essentially of a polymer having reactive silyl groups; a bituminous material; a compatibilizer in an amount effective to wet and help disperse the bituminous material in the polymer having reactive silyl groups; optionally, a catalyst for promoting fast reaction among the reactive silyl groups of the polymer having reactive silyl groups; optionally, effective amounts of one or more additives selected from dehydrating agents, tactifiers, physical property modifiers, storage stability improving agents, antioxidants, adhesion promoters, ultraviolet light absorbers, metal deactivators, antiozonants, light stabilizers, amine type radial chain inhibitors, phosphorous-containing peroxide decomposers, lubricants, pigments, foaming agents, flame retardants and antistatic agents. 15. The moisture curable composition of claim 14, wherein the polymer having reactive silyl groups is a polyester having reactive silyl groups, a polyether having reactive silyl groups, or a polyurethane having reactive silyl groups. 16. The moisture curable composition of claim 14, wherein the polymer having reactive silyl groups is an α, φ-telechelic silyl-terminated polymer. 17. The moisture curable composition of claim 14, wherein the polymer having reactive silyl groups is a silyl-terminated oxyalkylene polymer. 18. The moisture curable composition of claim 14, wherein the bituminous material is asphalt. 19. The moisture curable composition of claim 14, wherein the compatibilizer is an ester of a polyol with a fatty acid, the condensation product of a polycarboxylic acid and an alkanol, or a polyester polyol having repeating units derived from acrylic or methacrylic acid and a polyol. 20. The moisture curable composition of claim 14, wherein the bituminous material is present in an amount of from about 20 to about 175 parts by weight per 100 parts by weight of the polymer having reactive silyl groups. 21. The moisture curable composition of claim 14, wherein the bituminous material is present in an amount of from about 75 to about 150 parts by weight per 100 parts by weight of the polymer having reactive silyl groups. 22. The moisture curable composition of claim 14, wherein the composition is substantially free of volatile organic compounds. 23. The moisture curable composition of claim 14, wherein the composition is substantially free of isocyanate groups. 24. A composite waterproofing system composed of successive applications of moisture curing, solvent-free, asphalt modified, silyl terminated polyether, polyacrylate or polyurethane (SPUR) based liquid waterproofing compound and one or more sheets of polyester or fiberglass reinforcement scrimA composition. 25. A roof membrane system composed of two or more plies of polymer modified bitumen adhered to roof decks, insulation board and each other with a moisture curing, solvent-free, asphalt modified, silyl terminated polyether, polyacrylate, or polyurethane (SPUR) based adhesive. 26. A built-up cold process roofing system composed of an asphalt fiberglass base sheet, three successive plies of asphalt impregnated fiberglass felts, and a mineral granulated cap sheet laminated with a moisture curing, solvent free, asphalt modified, silyl terminated polyether, polyacrylate, or polyurethane (SPUR) based adhesive. 27. A self leveling expansion joint sealer used in horizontal joints in highways, parking structures and airport runways composed of an asphalt modified, solvent free, silyl terminated polyether, polyester, or polyurethane (SPUR) based sealant. 28. A corrosion resistant, waterproof automotive body sealant, or underbody coating composed of an asphalt modified, solvent free, silyl terminated polyether, polyester, or polyurethane (SPUR) based sealant. 29. A single ply roofing system composed of a fleece or felt backed polymer membrane based on EPDM rubber, PVC (vinyl), polyisobutylene, polysulfonated polyethelene (Hypalon), Elvaloy, butyl, or thermoplastic olefin (TPO). adhered directly to a roof deck, to rigid insulation board, or to gypsum or cement fireproof board with an of an asphalt modified, solvent free, silyl terminated polyether, polyester, or polyurethane (SPUR) based adhesive. 30. A waterproofing compound installed between slabs of concrete or as an underlayment beneath tile composed of an asphalt modified, solvent free, silyl terminated polyether, polyester, or polyurethane (SPUR) based liquid applied membrane. 31. The moisture curable composition of claim 1, which has been applied to a substrate and cured to form a film having a water permeability rating less than 0.1. 32. The moisture curable composition of claim 1, that is free of volatile organic compounds. | CROSS-REFERENCE TO RELATED APPLICATION This application claims priority under 35 U.S.C. § 119(e) on U.S. Provisional Application No. 60/520,235 entitled MOISTURE CURABLE SEALER AND ADHESIVE COMPOSITION, filed Nov. 14, 2003, by Philip C. Georgeau et al., the entire disclosure of which is incorporated herein by reference. FIELD OF THE INVENTION This invention relates to a moisture curable sealer composition that can be used for waterproofing construction surfaces, saturating felts in a cold process built-up roofing system, adhering modified bitumen roofing sheets, or fleece backed single ply roof membranes to roof decks and/or rigid roof insulation boards. BACKGROUND OF THE INVENTION Moisture curable sealer compositions are useful in a variety of applications where a waterproof seal is needed to prevent water from entering a joint or space between adjacent structural members. Examples of such applications include seals between roofing materials and parapet walls, highway and airport runway expansion joints, etc. Moisture curable sealer compositions can also be used for automotive body sealing and undercoating. Such compositions have also been employed for waterproofing various structures, such as concrete structures, and in a mastic or putty form for use in caulking and adhesive applications. In most cases, it is desirable to rapidly achieve a deep and complete cure. This usually reduces the possibility of forming defects, such as cracks, in the cured composition or seal. In many cases, a rapid cure is also desired to expedite subsequent construction or fabrication operations which cannot be performed until the sealer composition has cured. Various polymeric materials, especially polyurethanes, have been used extensively as coatings and sealants in construction, automotive, and other applications. However, a disadvantage with polyurethanes, silicones and other conventional moisture curing polymeric coatings and sealer compositions is that they cure slowly under ambient conditions and in cool weather. Polyurethanes and silicones require extensive exposure to atmospheric moisture and when installed between impermeable substrates cure poorly or not at all. Due to their low cost, and inherent water resistance, bituminous materials have traditionally been used as a main component of roof coatings, foundation coatings, paving, joint sealants, paints, and other end uses. However, existing unreinforced bituminous materials tend to melt, flow, or crack during normal seasonal thermal expansion and contraction. In the past, there have been several attempts to combine bituminous material with synthetic polymeric materials such as polyurethanes to make moisture curing compounds. However, these previous attempts have not been completely successful. In particular, the known combinations of synthetic polymeric materials and bituminous materials have not produced desirable synergistic qualities such as fast or deep cure. Coal tar has also been modified with urethanes and other synthetic polymers with similar limitations. SUMMARY OF THE INVENTION The present invention provides low cost moisture curable sealer and adhesive compositions having many advantages over conventional moisture cure sealer compositions. Advantages include greater elastomeric properties, improved flexibility and pliability, improved low temperature properties, and much greater impermeability to water. Of greater importance is the elimination of health risks associated with the use of other known moisture curable sealer compositions containing hazardous ingredients, such as isocyanates, aromatic solvents, and coal tar. The improved composition of this invention includes a bituminous material and a polymer having reactive silyl groups that cure upon exposure to very small amounts of atmospheric moisture, by means of an alkoxy cure mechanism, at temperatures as low as 20° F. The alkoxy reactive compound is very safe and it may be sprayed or otherwise applied, even in a confined space, without special chemical respirators, or full body skin protection. The toxicity of isocyanate reactive compounds is well known, and in several European countries isocyanates are prohibited because of their potential employee exposure risks. These and other features, advantages and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims and appended drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a modified bitumen roofing system assembly utilizing a moisture curable, solvent-free adhesive in accordance with the invention. FIG. 2 is perspective view of an asphalt built-up roofing system assembled with a moisture curable adhesive in accordance with the invention. FIG. 3 is perspective view of a single-ply fleece-backed roofing system assembly utilizing a solvent-free moisture curable adhesive composition in accordance with the invention. FIG. 4 is perspective view of a two-coat water proofing structure utilizing a reinforcement fabric in combination with a waterproof adhesive/coating composition in accordance with the invention. FIG. 5 is a perspective view of a horizontal joint seal in a concrete paving utilizing a joint sealer composition in accordance with the invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The compositions of this invention consist of, consist essentially of, or comprise a bituminous material, such as asphalt, and a silyl functional polymer. Preferred compositions also contain an organometalic catalyst, a plasticizer derived from soya oil, a hydrocarbon reinforcing resin, and fillers and/or extenders. Examples of silyl-terminated polymers that may be used in the moisture curable compositions of this invention include silylated polyethers, silylated polyacrylates and silylated polyurethane prepolymers (SPUR). The silylated polymers or silyl-terminated polymers used in the moisture curable compositions of this invention include two or more reactive silyl groups, e.g., α, ω-telechelic silyl-terminated polymers. An example of a suitable silyl-terminated polymer that may be used is an oxyalkylene polymer having at least one reactive silyl group at each end of the polymer molecule. The backbone of the silyl-terminated oxyalkylene polymer has repeating units represented by the formula: —R—O— wherein R represents a divalent organic group, preferably a straight or branched alkylene group containing 1 to 14 carbon atoms, and more preferably straight or branched alkylene groups containing 2 to 4 carbon atoms. Especially preferred are polypropylene oxide backbones, polyethylene oxide backbones, and copolyethylene oxide/polypropylene oxide backbones. Other repeating units may include, but are not limited to —CH2O—, —CH2CH(CH3)O—, —CH2CH(C2H5)O—, —CH2C(CH3)2O—, —CH2CH2CH2CH2O— and the like. The reactive silyl group contained in the silyl-terminated polymers may be represented by the formula: —[Si(R2)2-a(X)aO]p—Si(R3)3-b(X)b wherein R2 and R3 are the same or different and each represents an alkyl group containing 1 to 20 carbon atoms, an aryl groups containing 6 to 20 carbon atoms, an aralkyl group containing 7 to 20 carbon atoms or a triorganosiloxy group of the formula (R4)3 SiO— (wherein R4 independently represents a hydrocarbon group containing 1 to 20 carbon atoms) and, when two or more R2 and/or R3 groups are present, they may be the same or different; X represents a hydrolyzable group or a hydroxyl group and, when two or more X groups are present, they may be the same or different; a represents an integer of 0 to 2; b represents an integer of 0 to 3; and p represents an integer of 0 to 19 and, when p is 2 or more, the —[Si(R2)2-a(X)aO] groups may be the same or different. In the reactive silyl group represented by the above general formula, there is at least one hydrolyzable group or hydroxyl group represented by X. The above-mentioned alkyl group containing 1 to 20 carbon atoms includes, but is not limited to methyl, ethyl, isopropyl, butyl, t-butyl, cyclohexyl and the like. The above-mentioned aryl group containing 6 to 20 carbon atoms includes, but is not limited to, phenyl, naphthyl and the like. The above-mentioned aralkyl group containing 7 to 20 carbon atoms includes, but is not limited to, benzyl and the like. The above-mentioned monovalent hydrocarbon group containing 1 to 20 carbon atoms includes, but is not limited to, methyl, ethyl, isopropyl, butyl, t-butyl, pentyl, ethynyl, 1-propenyl, vinyl, allyl, 1-methylbutyl, 2-ethylbutyl, phenyl and the like. The above-mentioned hydrolyzable group represented by X is not limited to any particular species and includes a hydrogen atom, halogen atoms, and alkoxyl, acyloxy, ketoximate, amino, amido, acid amido, aminoxy, mercapto, alkenyloxy and the like groups. Among these, a hydrogen atom and alkoxyl, acyloxy, ketoximate, amino, amido, aminoxy, mercapto and alkenyloxy groups are preferred and, from the viewpoint of mild hydrolyzability and ease of handling, alkoxyl groups are particularly preferred. One to three hydroxyl groups and/or hydrolyzable groups each presented by X may be bound to one silicon atom. The sum total of the hydroxyl and/or hydrolyzable groups in the reactive silyl group represented by the above general formula is preferably within the range of 1 to 5. The number of silicon atoms forming the above-mentioned reactive silyl group may be 1 or 2 or more. In the practice of the present invention, those reactive silyl groups which are represented by the general formula shown below are preferred because of their ready availability: —Si(R3)3-bXb wherein R3, X and b are as defined above. Methods of introducing a reactive silyl group onto a polymer, such as a polyether, or more specifically a polyoxyalkylene polymer, are well known in the art. For example, polymers having terminal hydroxyl, epoxy or isocyanate functional groups can be reacted with a compound having a reactive silyl group and a functional group capable of reacting with the hydroxyl, epoxy or isocyanate group. As another example, silyl-terminated polyurethane polymers may be used. A suitable silyl-terminated polyurethane polymer may be prepared by reacting a hydroxyl-terminated polyether, such as a hydroxyl-terminated polyoxyalkylene, with a polyisocyanate compound, such as 4,4′-methylenebis-(phenylisocyanate), to form an isocyanate-terminated polymer, which can then be reacted with an aminosilane, such as aminopropyltrimethoxysilane, to form a silyl-terminated polyurethane. Silyl-terminated polyesters are those having the reactive silyl groups discussed above with a backbone comprising —O—CO—R5—CO—O—R6— or —R7—CO—O— repeat units, wherein R5, R6 and R7 are divalent organic groups such as straight or branched alkylene groups. The silyl-terminated polymers used in this invention may be straight-chained or branched, and typically have a weight average molecular weight of from about 500 to 50,000 Daltons, and more preferably from about 1,000 to about 30,000 Daltons. Suitable silyl-terminated polyethers are commercially available from Kaneka Corporation under the names KANEKA MS POLYMER™ and KANEKA SILYL™, and from Union Carbide Specialty Chemicals Division under the name SILMOD™. With conventional urethane compositions the cure requires one mole of water per mole of urethane linkages formed. Due to limitations on moisture diffusion, especially after the surface has cured (i.e., skinned over), deep cures take a very long time or do not occur at all with conventional urethane compositions. In contrast to the conventional urethane compositions, the moisture-curable polyesters, polyacrylates and polyurethanes used in the compositions of this invention release one mole of water for every mole of water used to achieve cure. Stated differently, water catalyzes curing of the compositions of this invention, but is not consumed during curing. In addition to the silyl-terminated polymer, the moisture curable compositions of this invention include a bituminous material. Bituminous materials include bitumen, asphalt, performance-rated asphalt (oxidized asphalt) and Gilsonite bituminous resins. The asphalt used may be straight run, blown, cracked and catalytically or non-catalytically polymerized asphalt, irrespective of their penetrations or softening points. Blown asphalts are normally produced in the presence or absence of catalyts by blowing asphalts or fluxes at elevated temperatures with an oxygen-containing gas such as air. A typical blown asphalt may have a softening point in the range from about 10° C. to about 100° C. Aromatic asphalts may also be employed, but are not preferred because they may present a health hazard to workers. Aromatic asphalts comprise the bottoms products from the distillation of catalytically cracked gas, oil or naphtha. Commercially available asphalts include those derived from residues produced by atmospheric and vacuum distillation of crude petroleum; oxidation or air blowing of asphalts derived from the residues produced during distillation of crude petroleum; deasphalting of petroleum residues of lubricating oils of asphalt origin; blending hard propane asphalts with resins and oils to produce the socalled “reconstituted asphalts.” Suitable asphalts include those having a rating of 60 Pen to 500 Pen (penetration). In general, the more highly oxidized (blown) asphalts are preferred if greater hardness is desired, whereas the less oxidized asphalts are desired if greater flexibility and pliability are desired. In general, it is preferred that the asphalts have relatively few reactive sites, such as hydroxyl groups, and that the asphalt be essentially anhydrous (dry). Further, it is desirable that the asphalt is substantially free of heterocyclic compounds or other compounds having reactive sites which will react with the functional groups on the silyl-terminated polymer. In order to facilitate miscibility between the silyl-terminated polymer and the bituminous material, it may be desirable or necessary to incorporate a compatibilizer or plasticizer that wets and helps disperse the asphalt or other bituminous material in the silyl-terminated polymer. Suitable compatibilizers have a substantially non-polar terminal portion and a substantially polar terminal portion. Examples include esters of a polyol (i.e., a molecule having at least two hydroxyl groups, e.g., a diol, triol, etc.) and a C9-C24 fatty acid; the condensation product of a polycarboxylic acid and a C9-C24 acyclic alkanol; an ester of a C10-C15, polyarylene polyester polyol such as recycled polyethylene terephthalate (PET) polyol with a C9-C24 fatty acid; an ester of a polyether diol derived from a polyalkadiene diol and C2-C24 fatty acid; an ester derived from polymethylsiloxane diol and a C2-C24 fatty acid; and a polyester polyol having a repeating unit derived from acrylic or methacrylic acid and a polyol selected from the group consisting of C2-C12 alkylene diol or triol, a polyalkylene diol, or a polyoxyalkylene diol. The compatibilizer may be employed in an amount from about 0.01 part to about 15 parts by weight based on 100 parts by weight of the moisture curable composition. Because the choice of an optimal compatibilizer and its concentration typically depends on the particular silyl-terminated polymer and asphalt employed, such choice can be made, and the concentration determined, using ordinary skill and routine experimentation. The compositions of this invention may be formulated as a one-part moisture curable, pourable sealer composition. Such compositions desirably contain a silanol condensation catalyst for promoting fast reaction among the reactive silyl groups contained in the silyl-terminated polymers. Examples of silanol condensation catalyst include, but are not limited to, titanate esters such as tetrabutyl titanate and tetrapropyl titanate; organotin compounds such as dibutyltin dilaurate, dibutyltin maleate, dibutyltin diacetate, stannous octylate, stannous naphthenate, reaction products from dibutyltin oxide and phthalate esters, and dibutyltin diacetylacetonate; organoaluminum compounds such a aluminum trisacetylacetonate, aluminum tris(ethylacetoacetate) and diisopropoxyaluminum ethyl acetoacetate; reaction products from bismuth salts and organic carboxylic acids, such as bismuth tris(2-ethylhexonate) and bismuth tris(neodecanoate); chelate compounds such as zirconium tetraacetylacetonate and titanium tetraacetylacetonate; organolead compounds such as lead octylate; organovanadium compounds; amine compounds such as butylamine, octylamine, dibutylamine, monoethanolamine, diethanolamine, triethanolamine, diethylenetriamine, triethylenetetramine, oleylamine, cyclohexylamine, benzylamine, diethylaminopropylamine, xylylenediamine, triethylenediamine, guanidine, diphenylguanidine, 2,4,6-tris(dimethylaminomethyl)phenol, morpholine, N-methylmorpholine, 2-ethyl-4-methylimidazole and 1,8-diazabicyclo (5.4.0)undecene-7 (DBU); salts of said amine compounds with carboxylic or other acids; low-molecular-weight polyamide resins derived from excess polyamines and polybasic acids; and reaction products from excess polyamines and epoxy compounds. These may be used individually or in combination. Among the silanol condensation catalysts mentioned above, organometallic compounds are preferred. The silanol condensation catalyst may be used in an amount of from about 0.01 to about 20 parts by weight per 100 parts by weight of the silyl-terminated polymer, with a more preferred addition level being from about 0.1 to about 10 parts by weight per 100 parts by weight of the silyl-terminated polymer. In the curable compositions of the present invention, there may further be added, when necessary, various additives such as dehydrating agents, tackifiers, physical property modifiers, storage stability improving agents, fillers, antioxidants, adhesion promoters, ultraviolet absorbers, metal deactivators, antiozonants, light stabilizers, amine type radical chain inhibitors, phosphorus-containing peroxide decomposers, lubricants, pigments, anti-foaming agents, flame retardants and antistatic agents, each in an adequate amount. The fillers mentioned above include, but are not limited to, wood meal, walnut shell flour, rice hull flour, pulp, cotton chips, mica, graphite, diatomaceous earth, china clay, kaoline, clay, talc, fumed silica, precipitated silica, silicic anhydride, quartz powder, glass beads, calcium carbonate, magnesium carbonate, titanium oxide, carbon black, glass balloons, aluminum powder, zinc powder, asbestos, glass fiber, fly ash and carbon fiber. The above fillers may be used individually or in combination. The moisture curable compositions of this invention may contain from about 10 to about 175 parts by weight of bituminous material per 100 parts by weight of silyl-terminated polymer, with a more preferred range being from about 75 to about 150 parts by weight of bituminous material per 100 parts by weight of silyl-terminated polymer. Preferably, the compositions of this invention are formulated without volatile organic solvents, and/or comprise, consist of, or consist essentially of one or more silyl-terminated polymers, and one or more bituminous materials. Optional additives that do not adversely affect and may enhance the essential characteristics and features of the invention include fillers, a compatibilizer that enhances miscibility between the silyl-terminated polymer and the bituminous material, optionally a catalyst that promotes moisture curing, and conventional amounts of conventional additives, such as dehydrating agents, compatibilizers, tactifiers, physical property modifiers, storage stability improving agents, antioxidants, adhesion promoters, ultraviolet absorbers, metal deactivators, antiozonants, light stabilizers, amine type radical chain inhibitors, phosphorous-containing peroxide decomposers, lubricants, pigments, foaming agents, flame retardants and antistatic agents. The compositions of this invention may be formulated as paint or coating compositions by utilizing little, if any, fillers and/or other thixatropic agents. Alternatively, relatively thick pastes or compositions having a consistency or viscosity anywhere between a coating composition or a relatively thick paste may be achieved by adding suitable amounts of fillers and/or other thixatropic agents. In general, the compositions of this invention have several advantages over conventional sealer compositions including conventional asphaltic/urethane compositions. There advantageous include lower costs, greater elastomeric properties, improved flexibility and pliability, and lower durometer (e.g., a Shore A of about 20 versus 30-40 for most conventional sealants. An adhesive composition of this invention may be advantageously employed as a layer or film 10 for adhering a base sheet 12 of roofing materials, such as a polymer modified bitumen membrane (as shown in FIG. 1) to a roof deck 14. A second layer or film 16 of the adhesive composition may be employed to adhere a cap sheet 18 to the base sheet 12. A cold process built-up roofing system (as shown in FIG. 2) can also be constructed with a composition of this invention, replacing dangerous molten asphalt and solvent based asphalt adhesives with a safe solvent free, moisture curable adhesive. The built-up roofing system shown in FIG. 2 includes a base layer or film 20 of adhesive disposed between a roof deck 22 and a fiberglass base sheet 24. Additional alternating layers of adhesive 20 and fiberglass sheet 24 may be added as desired. The structure may be completed by adhering a granulated asphalt cap sheet 28 to the last sheet 26. The resulting thermosetting moisture cure multi ply composite forms a highly elastomeric roof system capable of accommodating substantial building movement and substrate expansion and contraction at high and low temperatures. Because of the superior waterproof and water vapor barrier properties of the compositions of this invention, water accumulated across the roof surface would not gain entry to the dry insulation and deck structure beneath the built-up waterproof composite. The compositions of this invention may also be advantageously employed as a layer or film 30 for adhering fleece backed single ply rubber membranes such as EPDM membranes 32, or the like (e.g., butyl rubber, polyisobutylene (PIB) thermoplastic olefin (TPO), polyvinyl chloride (PVC)) to an insulation board or a rigid concrete roof deck structure 34 (as shown in FIG. 3). As shown in FIG. 4, an adhesive composition in accordance with the invention may be applied to a roof deck 40 to form a thin layer or coating 42 for adhering a reinforcement fabric 44 (e.g., a polyester fiber reinforced fabric) and a top coat of the waterproof compositions of this invention may be applied over reinforcement fabric 44 in a thin layer or film 46 to form a membrane in a two-coat roof waterproofing structure. As shown in FIG. 5, a joint sealer composition in accordance with the invention may be utilized to prepare a horizontal joint seal in a concrete paving. As shown in FIG. 5, a backer rod 50 (typically made of a material that does not bond well to the sealer composition (e.g. polyethylene)) is disposed in the gap between adjacent concrete slabs 52 and 53 to prevent the sealer composition from penetrating into the ground, and thereafter sealer composition 54 is deposited into the remaining space between slabs 52 and 53 over backer rod 50 to form a horizontal joint seal in a concrete paving. As illustrated, sealer 54 completely fills the space between slabs 52 and 53 so that the top surface of the cured joint seal is flush with the top of the concrete slabs. Low viscosity compositions of this invention may be used alone as a waterproof coating, or as a multi-ply composite layered in succession with reinforcing fabrics composed of fiberglass or polyester filaments. Such elastomeric composites would be used for waterproofing underground structures where substrate movement and hydrostatic pressure is encountered. The compositions of this invention may also be formulated at a higher viscosity, for use as a sealing compound in expansion joints for highways and airport runways and parking structures. This is a particularly promising application in view of the materials excellent waterproof properties, adhesion, and elastomeric properties. The compositions of this invention may also be formulated for various other waterproofing, caulking, and sealing applications, including various automotive, building and construction applications. EXAMPLE 1 The following example of a one-part moisture curable, waterproof coating composition illustrates the invention in further detail, but does not limit the scope of the invention. The illustrative composition includes the following ingredients in the amounts indicated: Asphalt - Trumble 4004 20.5% Pyrolin - C9 hydrobarbon resin 5% Methyl Soyate Plasticizer 7.3% Silyl-terminated Polyacrylate - (Kaneka MAX-601) 20.0% Calcium Carbonate - (Huber Q-3) 45.5% Fumed Silica - (Cabot M-5) 0.4% Dehydrating Agent - (WITCO A-171 vinyl silane) 0.7% Adhesion Promoter - (WITCO A-1120 amino silane coupling 0.5% agent) Organo Tin Catalyst - (FOAMREZ SUL-11A) 0.5% . The above composition forms a skin within about 30 minutes and cures to a waterproof 30 mil film thickness within about two hours at room temperature. This compares very favorably with other commercially available urethane/asphalt moisture cure waterproofing compositions which form a skin in about one to two days and cure to a 30 mil film thickness in about two to three days at room temperature. Also, the above composition may be applied at lower temperatures than the commercially available urethane/asphalt blend. The illustrative example of the invention can be applied at temperatures as low as about 30° F., whereas application of the commercially available urethane/asphalt waterproofing composition is limited to a temperature of 40° F. Also, the illustrative composition of this invention is safer to the environment and to workers using the compositions. The compositions of this invention achieve a water permeability rating of less than 0.1 (e.g., 0.04 for Example 1) when tested in accordance with ASTM E96. Comparable urethane/asphalt compounds, such as Sonneborn HLM 5000, only achieve water permeability ratings of 0.9. In particular, the illustrative composition does not contain any volatile organic solvents, and does not contain any isocyanate compounds, whereas the commercially available urethane/asphalt waterproofing composition contains from about 8 to about 20% volatile organic solvent and from about 10 to about 30% by weight isocyanate compounds. Also, the compositions of this invention do not foam upon application over moist concrete, whereas the commercially available urethane/asphalt waterproofing compositions do foam upon application over moist concrete. EXAMPLE 2 The following example of a one-part moisture curable, adhesive composition illustrates the invention in further detail, but does not limit the scope of the invention. The illustrative composition includes the following ingredients in the amounts indicated: Asphalt - (Trumble 4004) 22.49% Hydrocarbon Resin - (Pyrolen 100) 8.8% Methyl Soyate plasticizer - (Colombia) 16.63% Crayvalac Super thixotrope - (Cray Valley) 1.22% Mistron Vapor Talc - (Cyprus Mines) 4.89% Filler - (Cenospheres) 22.49% Silyl Terminated Polyether - (Kaneka MS 303) 22.49% A 171 vinyl silane - (OSI) 0.78% A 1120 amino silane - (OSI) 0.68% Sul 11A catalyst - (OSI) 0.49% Di butyl tin dilaurate - catalyst - (Air Products) 0.49% . The adhesive described in the above composition can be applied with a brush or squeegee to sheet roofing substrates. A 20 mil application skins over in thirty minutes at 70° F. and in fifteen minutes at 90° F. The adhesive attains a complete cure in twenty-four hours in bonds composed of four foot wide, moisture impermeable, modified between roofing sheets. The above description is considered that of the preferred embodiments only. Modifications of the invention will occur to those skilled in the art and to those who make or use the invention. Therefore, it is understood that the embodiments described above are merely for illustrative purposes and not intended to limit the scope of the invention, which is defined by the following claims as interpreted according to the principles of patent law, including the doctrine of equivalents. | <SOH> BACKGROUND OF THE INVENTION <EOH>Moisture curable sealer compositions are useful in a variety of applications where a waterproof seal is needed to prevent water from entering a joint or space between adjacent structural members. Examples of such applications include seals between roofing materials and parapet walls, highway and airport runway expansion joints, etc. Moisture curable sealer compositions can also be used for automotive body sealing and undercoating. Such compositions have also been employed for waterproofing various structures, such as concrete structures, and in a mastic or putty form for use in caulking and adhesive applications. In most cases, it is desirable to rapidly achieve a deep and complete cure. This usually reduces the possibility of forming defects, such as cracks, in the cured composition or seal. In many cases, a rapid cure is also desired to expedite subsequent construction or fabrication operations which cannot be performed until the sealer composition has cured. Various polymeric materials, especially polyurethanes, have been used extensively as coatings and sealants in construction, automotive, and other applications. However, a disadvantage with polyurethanes, silicones and other conventional moisture curing polymeric coatings and sealer compositions is that they cure slowly under ambient conditions and in cool weather. Polyurethanes and silicones require extensive exposure to atmospheric moisture and when installed between impermeable substrates cure poorly or not at all. Due to their low cost, and inherent water resistance, bituminous materials have traditionally been used as a main component of roof coatings, foundation coatings, paving, joint sealants, paints, and other end uses. However, existing unreinforced bituminous materials tend to melt, flow, or crack during normal seasonal thermal expansion and contraction. In the past, there have been several attempts to combine bituminous material with synthetic polymeric materials such as polyurethanes to make moisture curing compounds. However, these previous attempts have not been completely successful. In particular, the known combinations of synthetic polymeric materials and bituminous materials have not produced desirable synergistic qualities such as fast or deep cure. Coal tar has also been modified with urethanes and other synthetic polymers with similar limitations. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention provides low cost moisture curable sealer and adhesive compositions having many advantages over conventional moisture cure sealer compositions. Advantages include greater elastomeric properties, improved flexibility and pliability, improved low temperature properties, and much greater impermeability to water. Of greater importance is the elimination of health risks associated with the use of other known moisture curable sealer compositions containing hazardous ingredients, such as isocyanates, aromatic solvents, and coal tar. The improved composition of this invention includes a bituminous material and a polymer having reactive silyl groups that cure upon exposure to very small amounts of atmospheric moisture, by means of an alkoxy cure mechanism, at temperatures as low as 20° F. The alkoxy reactive compound is very safe and it may be sprayed or otherwise applied, even in a confined space, without special chemical respirators, or full body skin protection. The toxicity of isocyanate reactive compounds is well known, and in several European countries isocyanates are prohibited because of their potential employee exposure risks. These and other features, advantages and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims and appended drawings. | 20040120 | 20080108 | 20050519 | 60025.0 | 0 | SASTRI, SATYA B | MOISTURE CURABLE SEALER AND ADHESIVE COMPOSITION | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,761,445 | ACCEPTED | Combined single-twin street sweeping machine | A surface cleaning vehicle is provided with hydraulically driven sweeping machinery. The vehicle comprises a truck chassis for carrying the sweeping machinery and a prime mover engine for propelling the vehicle. A second engine is connected to said chassis, and first and second pumps and associated check valves are connected to respective ones of the prime mover and second engines for driving said sweeping machinery. A control mechanism is provided for selectively connecting only one of the prime mover engine or second engine to drive the sweeping machinery. | 1. A surface cleaning vehicle with hydraulically driven sweeping machinery, comprising: a truck chassis for carrying said sweeping machinery and a prime mover engine for propelling said vehicle; a second engine connected to said chassis; first and second pumps and associated check/isolation valves connected to respective ones of said prime mover and second engines for driving said sweeping machinery; and a control mechanism for selectively connecting only one of said prime mover engine or said second engine to drive said sweeping machinery. 2. The surface cleaning vehicle of claim 1, further comprising a power-take-off unit intermediate said first pump and said prime mover engine. 3. The surface cleaning vehicle of claim 1, wherein at least one of said pumps is a variable displacement pump. 4. The surface cleaning vehicle of claim 1, wherein at least one of said pumps is a fixed displacement pump. 5. The surface cleaning vehicle of claim 2, further comprising an additional control mechanism for increasing the low idle speed of said prime mover engine when said power-take-off unit is engaged. 6. The surface cleaning vehicle of claim 2, wherein said control mechanism further comprises a master switch and a mode selector switch, said mode selector switch having a SINGLE position and a TWIN position, and said master switch having an OFF position, a START position for starting said second engine in the event said mode selector switch is in the TWIN position or engaging said power-take-off unit in the event said mode selector switch is in the SINGLE position, and a RUN position for continued operation of said second engine in the event said mode selector switch is in the TWIN position or said power-take-off unit in the event said mode selector switch is in the SINGLE position. 7. The surface cleaning vehicle of claim 6, further comprising a latching relay connected to said mode selector switch for holding the power-take-off unit in engagement in response to being energized via said mode selector switch. 8. The surface cleaning vehicle of claim 6, wherein said master switch is spring loaded such that upon being released from said START position the master switch returns to said RUN position. 9. The surface cleaning vehicle of claim 6, wherein said control mechanism includes means for disabling operation of said second engine in the event said mode selector switch is changed from the TWIN position to the SINGLE position while said second engine is running, and for disabling operation of said power-take-off unit in the event said mode selector switch is changed from the SINGLE position to the TWIN position while said power-take-off unit is running. 10. The surface cleaning vehicle of claim 6, further including a vehicle ignition switch for starting said prime mover engine and providing power to the control mechanism, such that opening said ignition switch disables operation of said sweeping machinery. 11. The surface cleaning vehicle of claim 1, wherein said hydraulically driven sweeping machinery is mechanically operated. 12. The surface cleaning vehicle of claim 1, wherein said hydraulically driven sweeping machinery is pneumatically operated. 13. The surface cleaning vehicle of claim 12, wherein said hydraulically driven sweeping machinery is pneumatically operated using vacuum. 14. The surface cleaning vehicle of claim 12, wherein said hydraulically driven sweeping machinery is pneumatically operated using regenerative air. | BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to surface cleaning vehicles, and more particularly to a combined single and twin power system for independently driving sweeping machinery of a surface cleaning vehicle. 2. Description of the Related Art Street cleaning vehicles are well known in the art having mechanical conveying systems, either in the form of a conveyor elevator that drags collected debris up an inclined ramp or via an inclined conveyor belt. The discharge from the conveyor is deposited into a hopper that is provided with a tipping mechanism for discharge. Street cleaning vehicles employing pneumatic conveying systems are also well known in the art, and fall into two categories, vacuum and regenerative. Both categories of machine employ an exhauster fan to induce high velocity airflow for conveying the debris through a conduit. Regenerative machines additionally utilize the exhauster fan to aid the collection system, whereas vacuum machines do not. In general, pneumatic conveying systems have a much greater power requirement, as compared to mechanical conveyors, as a result of using the exhauster fan to perform the debris collection and conveying functions. The power requirement for driving the brooms is similar for both types of machines. The conveying system may be driven either by the prim mover engine used to propel the vehicle—referred to herein as ‘Single’, or by utilizing a separate engine—referred to herein as ‘Twin’. Single mechanical machines utilize the vehicle's prime moving engine to drive the sweeping mechanisms. More particularly, the sweeping and conveying equipment is hydraulically driven by a pump or pumps coupled to the prime mover engine via a disconnectable power-take-off. The engine and transmission forming part of the carrier vehicle, require little or no change to the driveline and produce sufficient power for the sweeping mechanisms when running at low engine speeds that occur when driving the vehicle slowly, for example at less than 5 MPH (8 km/h). The single machine design enjoys the perception of simplicity in terms of construction and operation. The only criterion of the single design is that, at low speeds, the prime mover engine provides sufficient power to drive the sweeping equipment and perform effectively (i.e. when the vehicle is being driven slowly. Machines of the ‘single’ type have been to be best suited to municipal operations associated with lighter duty street cleaning operations where the machine provides adequate performance (e.g. 40 to 50 Horsepower (30 to 40 kilowatts)) at low operating costs. Pneumatic machines often incorporate the aforenoted second engine, or ‘twin’ configuration, to drive the sweeping equipment. More particularly, the sweeping and conveying equipment is driven by a mechanical transmission or by a fluid power mechanism powered by a pump or pumps coupled to the second engine. Although there are examples of single engine pneumatic machines, these machines employ auxiliary driveline systems using hydrostatics and/or mechanical gearboxes to enable power to be extracted from the engine at higher speeds whilst maintaining slow sweeping speeds. These modifications greatly increase the cost and complexity of the machine. Moreover, a prime-mover engine of higher than usual power is often required, which tends to further increase the initial cost. In general, the driveline configuration requirements of the carrier vehicle for a ‘mechanical’ machine are similar to those of a normal commercial transport vehicle with automatic transmission. The vehicle specifications are similar for both the single and twin designs. The twin design offers more flexibility than the single design in terms of operating modes, since there are no requirements of the prime-mover engine in terms of power or speeds. The sweeping and conveying functions operate independently of how the vehicle is driven, which vary according to the conditions of work (i.e. stop, start, forward, reverse, slow, fast, etc.). By using a second engine, it is possible to design a twin machine with higher sweeping and conveying performance on a given type of vehicle than would be possible with a similar power rating of prime mover engine of single machine design. The flexibility in operation and corresponding sweeping performance are the major advantages of the twin design. These advantages make the twin design best suited to duties associated with industrial activities, road construction and where heavier duty sweeping conditions prevail. The disadvantages are that the machine incurs additional operational costs for fuel and maintenance and there is a perception of increased complexity over single machine design, as a result of using two engines. SUMMARY OF THE INVENTION It is an aspect of the present invention to provide a combined single and twin power system for independently driving sweeping machinery of a surface cleaning vehicle. According to the invention, both the single and twin designs are combined into one machine with a selectable mode of operation. The benefit to the operator is the ability to work in the lower cost single mode for most of the time, with the option to switch to twin mode for heavy-duty sweeping tasks (e.g. seasonal tasks such as spring cleanup following winter gritting, or in emergency situations). Preferably, an hour and distance counter is provided to record the operation when working in either single or twin mode. This allows a contractor to use a variable scale of charges according to the type of work and conditions contracted to. These together with other aspects and advantages which will be subsequently apparent, reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation view of a surface cleaning vehicle having a mechanical sweeping apparatus operable in single and twin operating modes, according to a preferred embodiment of the invention. FIG. 2 is a schematic block diagram of the drivelines from the prime mover engine and from the second engine and the fluid-power link to the sweeping equipment system, for the vehicle of FIG. 1. FIG. 3 is a schematic diagram of the electrical control system for discrete operation of either single or twin modes, for the vehicle of FIG. 1. FIG. 4 is an elevation view of a surface cleaning vehicle having a pneumatic vacuum sweeping apparatus operable in combined single and twin operating modes, according to a first alternative embodiment of the invention. FIG. 5 is an elevation view of a surface cleaning vehicle having a pneumatic regenerative sweeping apparatus operable in combined single and twin operating modes, according to a second alternative embodiment of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a base vehicle is provided with a commercially available truck chassis 1 with prime-mover engine. According to the preferred embodiment, a truck is provided having a gross vehicle mass of nominally 15000 kilograms, a prime mover engine of greater than 175 Horsepower (130 kilowatts) at 2200 rpm, and a torque converter coupling between the engine and transmission. Automatic transmission is provided which, when coupled with the rear axle ratio, allows the vehicle to be driven at slow speed (e.g. 2 MPH (3 km/h)). A second, ‘twin’ engine 2 is provided, having sufficient power (typically 60 Horsepower (45 kilowatts)), to drive sweeping equipment including scarifying brooms 3 and 4, and conveyor elevator 5. The debris is deposited from conveyor 5 into a hopper 6, in a well known manner. Referring to FIG. 2, the vehicle driveline is shown comprising a prime mover engine 20, torque converter 21 and automatic transmission 22 connected to a propeller shaft 23. The propeller shaft is connected to a rear axle for driving the rear wheels of the truck. The driveline components are connected to the main functional components of the mechanical sweeping equipment and fluid power systems 24, which are common for the single and twin operating modes. The only variance is that power to the systems 24 is provided either by the single or twin fluid power pump/s 25 via shuttle or check valves 26. The control system of FIG. 3 operates the pump/s 25, ensuring that only one pump 25 can be in operation at any particular time. As illustrated, power-take-off (PTO 27) is included, with engagement and disengagement of the PTO 27 under dynamic conditions, to power the sweeping equipment fluid power pump/s 25. The pumps 25 in both systems can be variable displacement units with control mechanisms to deliver a uniform flow once a minimum operating speed has been met. Alternatively, the pump/s 25 coupled to the second engine can be of fixed displacement design. The ‘single’ operation component has an additional control to the prime mover engine, to increase its low idle speed to nominally 900 rpm when the PTO 27 is engaged. At this speed, the engine 20 has sufficient power to drive the pump 25 and not be prone to stalling once the accelerator foot pedal is fully relaxed. The pump is configured to deliver a predetermined flow of fluid, so that any increase in speed above this setting does not increase the fluid flow. The above-described additional control to the prime mover engine for increasing the speed function is a feature of the carrier vehicle and is offered in the supplier's specification when auxiliary equipment is to be driven. Typically an electrical connection from the sweeper control (in this case by the master stop/start switch via the mode select switch, discussed in greater detail below with reference to FIG. 3) is made to the engine's ECU (Electronic Control Unit) to effect the operation. Similarly, a parallel connection is made to engage the PTO function to drive the pump/s 25 as indicated in FIG. 3. At the low engine speed of 900 rpm the torque converter 21 only delivers a portion of its normal torque capability. The application of the vehicle's braking system can be administered to arrest it in order to achieve very low vehicle creeping speeds or static condition when the transmission is in its lowest gear by stalling the converter 21. In this working condition, the vehicle's speed is controlled in a similar fashion to that of a regular transport vehicle by means of an ‘accelerator’ foot pedal that can vary the engine speed throughout the normal speed range, or by the application of the brakes. Increasing the engine speed not only delivers more engine power but also increases the torque capacity of the converter 21 and allows the vehicle to be propelled up inclines. By employing the variable displacement pump with a control that maintains a constant flow, increasing the engine speed does not increase the fluid flow or the power requirement to drive it. Therefore, the pump 25 is capable of operating throughout the engine's entire speed range. For the twin mode of operation, the second engine 2 and fluid power pump/s 25 are matched in terms of speed and power etc. to deliver a similar or preferably a greater fluid flow when compared to the single mode of operation. In the twin operating mode, the second engine 2 is set to run at a set speed and the vehicle may be driven in the normal fashion at any speed. As discussed above, a feature of the present invention is that it is only possible to operate the vehicle in either the single or twin mode but not in both modes simultaneously. FIG. 3 shows the electrical control system for operating the PTO 27 or the second engine 2. Two switches are employed: a master switch and a two position mode selector for switching between single and twin modes of operation. The master switch has three positions (0) Off, (1) Run and (2) Second-Engine-Start or PTO engagement. For position (2) the switch is ‘Hold to Run’ and once released springs back to position (1). Switching from position (0) to position (1) provides power to either the engine 2 or the PTO 27 depending on the position of the selector switch. Switching to position (2) either starts the engine 2 by-way of its starter motor or engages the PTO 27 and increases the engine idle speed. A latching relay is provided to hold the PTO 27 in engagement with increased engine speed once energized. When the mode selector switch is returned to position (0), the power is severed to whichever of the engine 2 or PTO 27 is in operation at the time, and the engine 2 either shuts-down or the PTO disengages 27 accordingly. Power to the master start/stop switch is received from the carrier vehicle power supply, once its ‘ignition key’ or isolation switch has been activated. Operating the mode selector switch when one of the systems is in operation also has the same effect as shutting-down. To start-up in a new selected mode, it is necessary to re-activate the master switch to position (2). This control feature is also extended to the condition when the carrier vehicle's ignition key is switched-off, in which case it is necessary to activate the master switch to initiate machine operation once the ignition key switch has again been switched to the ‘on’ position. This re-start feature has been implemented in the design to avoid the condition of an unexpected start-up in the event that the mode selector is inadvertently disturbed, or following a situation where the vehicle's ignition key switch is turned-on and the prime mover engine started with master switch set in the run (1) position. Whilst it may be inferred from the foregoing that application of the present invention may not be practical in pneumatic machine, there is no technical impediment to such application, although cost may be a disincentive in some circumstances. The invention is, nonetheless, equally applicable to both mechanical surface cleaning machines, as shown in FIG. 1, or pneumatic surface cleaning machines as shown in FIGS. 4 and 5. FIG. 4 depicts a surface cleaning machine with vacuum-operated sweeping apparatus, according to a first alternative embodiment. A tipping hopper 41 is mounted to the truck chassis for collecting and, upon tipping, discarding collected trash. The sweeping arrangement includes a gutter broom 42 and main broom 43 for directing debris toward a pick-up nozzle 45 of a suction conveyor duct 44. A vacuum wander hose 46 is also provided, as is known in the art. A vacuum suction fan is selectively operated either in single mode, or via an auxiliary engine power unit 47 for twin mode, as discussed above in connection with FIGS. 2 and 3. FIG. 5 depicts a surface cleaning machine with regenerative air sweeping apparatus, according to a second alternative embodiment. The sweeping arrangement includes gutter brooms and pick-up head 51 selectively operated either in single mode, or via an auxiliary engine power unit 52 for twin mode, as discussed above in connection with FIGS. 2 and 3. Debris directed by the brooms and pick-up head 51 is drawn into hopper 55 via a combination blower/suction fan and air blast discharge duct 54. A vacuum wander hose 53 is also provided, as is known in the art. The tipping hopper 55 is mounted to the truck chassis for collecting and, upon tipping, discarding collected trash. The many features and advantages of the invention are apparent from the detailed specification and, thus, it is intended by the appended claims to cover all such features and advantages of the invention that fall within the true spirit and scope of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention is directed to surface cleaning vehicles, and more particularly to a combined single and twin power system for independently driving sweeping machinery of a surface cleaning vehicle. 2. Description of the Related Art Street cleaning vehicles are well known in the art having mechanical conveying systems, either in the form of a conveyor elevator that drags collected debris up an inclined ramp or via an inclined conveyor belt. The discharge from the conveyor is deposited into a hopper that is provided with a tipping mechanism for discharge. Street cleaning vehicles employing pneumatic conveying systems are also well known in the art, and fall into two categories, vacuum and regenerative. Both categories of machine employ an exhauster fan to induce high velocity airflow for conveying the debris through a conduit. Regenerative machines additionally utilize the exhauster fan to aid the collection system, whereas vacuum machines do not. In general, pneumatic conveying systems have a much greater power requirement, as compared to mechanical conveyors, as a result of using the exhauster fan to perform the debris collection and conveying functions. The power requirement for driving the brooms is similar for both types of machines. The conveying system may be driven either by the prim mover engine used to propel the vehicle—referred to herein as ‘Single’, or by utilizing a separate engine—referred to herein as ‘Twin’. Single mechanical machines utilize the vehicle's prime moving engine to drive the sweeping mechanisms. More particularly, the sweeping and conveying equipment is hydraulically driven by a pump or pumps coupled to the prime mover engine via a disconnectable power-take-off. The engine and transmission forming part of the carrier vehicle, require little or no change to the driveline and produce sufficient power for the sweeping mechanisms when running at low engine speeds that occur when driving the vehicle slowly, for example at less than 5 MPH (8 km/h). The single machine design enjoys the perception of simplicity in terms of construction and operation. The only criterion of the single design is that, at low speeds, the prime mover engine provides sufficient power to drive the sweeping equipment and perform effectively (i.e. when the vehicle is being driven slowly. Machines of the ‘single’ type have been to be best suited to municipal operations associated with lighter duty street cleaning operations where the machine provides adequate performance (e.g. 40 to 50 Horsepower (30 to 40 kilowatts)) at low operating costs. Pneumatic machines often incorporate the aforenoted second engine, or ‘twin’ configuration, to drive the sweeping equipment. More particularly, the sweeping and conveying equipment is driven by a mechanical transmission or by a fluid power mechanism powered by a pump or pumps coupled to the second engine. Although there are examples of single engine pneumatic machines, these machines employ auxiliary driveline systems using hydrostatics and/or mechanical gearboxes to enable power to be extracted from the engine at higher speeds whilst maintaining slow sweeping speeds. These modifications greatly increase the cost and complexity of the machine. Moreover, a prime-mover engine of higher than usual power is often required, which tends to further increase the initial cost. In general, the driveline configuration requirements of the carrier vehicle for a ‘mechanical’ machine are similar to those of a normal commercial transport vehicle with automatic transmission. The vehicle specifications are similar for both the single and twin designs. The twin design offers more flexibility than the single design in terms of operating modes, since there are no requirements of the prime-mover engine in terms of power or speeds. The sweeping and conveying functions operate independently of how the vehicle is driven, which vary according to the conditions of work (i.e. stop, start, forward, reverse, slow, fast, etc.). By using a second engine, it is possible to design a twin machine with higher sweeping and conveying performance on a given type of vehicle than would be possible with a similar power rating of prime mover engine of single machine design. The flexibility in operation and corresponding sweeping performance are the major advantages of the twin design. These advantages make the twin design best suited to duties associated with industrial activities, road construction and where heavier duty sweeping conditions prevail. The disadvantages are that the machine incurs additional operational costs for fuel and maintenance and there is a perception of increased complexity over single machine design, as a result of using two engines. | <SOH> SUMMARY OF THE INVENTION <EOH>It is an aspect of the present invention to provide a combined single and twin power system for independently driving sweeping machinery of a surface cleaning vehicle. According to the invention, both the single and twin designs are combined into one machine with a selectable mode of operation. The benefit to the operator is the ability to work in the lower cost single mode for most of the time, with the option to switch to twin mode for heavy-duty sweeping tasks (e.g. seasonal tasks such as spring cleanup following winter gritting, or in emergency situations). Preferably, an hour and distance counter is provided to record the operation when working in either single or twin mode. This allows a contractor to use a variable scale of charges according to the type of work and conditions contracted to. These together with other aspects and advantages which will be subsequently apparent, reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout. | 20040121 | 20061219 | 20050721 | 91773.0 | 0 | REDDING, DAVID A | COMBINED SINGLE-TWIN STREET SWEEPING MACHINE | SMALL | 0 | ACCEPTED | 2,004 |
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10,761,487 | ACCEPTED | Systems, methods and apparatus for operating a broadcast network | In a method for operating a radio station, the radio station periodically receives content files via a satellite data channel. The received content files are stored. At least some of the stored files are then retrieved, played and broadcast in accordance with an electronic schedule. In accordance with another method, a plurality of affiliate radio stations are provided with content files via a satellite-based content delivery system. Each of the affiliate radio stations is also provided with an electronic schedule that instructs an automation system of the affiliate radio station to retrieve, play and broadcast ones of the content files, thereby generating a near real-time radio broadcast. Methods and apparatus for recording said content files for tiers of affiliates, and for recording said content for multiple or singular affiliates, are also disclosed. | 1. A method for operating a radio station, comprising: periodically receiving content files via a satellite uplink; storing the received content files; and retrieving, playing and broadcasting at least some of the stored content files in accordance with an electronic schedule. 2. The method of claim 1, wherein the electronic schedule is at least partly derived from a network schedule that is provided to the radio station via the satellite uplink. 3. The method of claim 1, wherein the electronic schedule is at least partly derived from a network schedule that is provided to the radio station via an internet connection. 4. The method of claim 1, further comprising generating the electronic schedule by merging i) a network schedule received from a content provider, and ii) a local schedule maintained at the radio station. 5. The method of claim 4, wherein said network schedule and local schedule are merged once an hour to generate the electronic schedule for the next hour. 6. The method of claim 4, further comprising, when merging said network and local schedules: identifying breaks in the network schedule; determining, for each break, whether the local schedule specifies at least a minimum quantity of content for the break, and i) if the local schedule specifies a minimum quantity of content for the break, filling the break with the specified content; and ii) if the local schedule does not specify a minimum quantity of content for the break, filling the break with the specified content, if any, and optional content specified by the network schedule. 7. The method of claim 6, wherein the minimum quantity of content is at least ninety seconds of content. 8. The method of claim 6, wherein: the network schedule specifies optional content for each break in the network schedule; and if optional content is used to fill a break in the network schedule, all of the optional content specified for the break is used. 9. A method, comprising: providing a plurality of affiliate radio stations with content files via a satellite-based content delivery system; providing each of the affiliate radio stations with an electronic schedule that instructs an automation system of the affiliate radio station to retrieve, play and broadcast ones of the content files, thereby generating a near real-time radio broadcast. 10. The method of claim 9, wherein different electronic schedules are provided to the affiliate radio stations corresponding to each of a number of different radio broadcast formats. 11. The method of claim 9, wherein the electronic schedules provided to at least two of the affiliate radio stations each reference a given content file indicator; the method further comprising: recording at least two different content files for the given content file indicator, and associating each of the different content files with a different token; and in response to said different tokens, said satellite-based content delivery system providing a different content file to each of the at least two affiliate radio stations. 12. A radio network, comprising: a plurality of affiliate radio stations; a content provider, linked to the plurality of affiliate radio stations via a satellite-based content delivery system, providing content to each of the affiliates in the form of discrete content files. 13. The radio network of claim 12, wherein the content provider uses a one-way link of the satellite-based content delivery system to transfer content files to ones of the affiliate radio stations. 14. The radio network of claim 13, wherein the content provider is further linked to the plurality of affiliate radio stations via a bidirectional internet return link that provides a backup connection for transferring content files to ones of the affiliate radio stations. 15. The radio network of claim 12, wherein the content provider comprises: an origination component providing operators of the content provider an interface to record and manage content files that are to be transmitted to the affiliate radio stations; and a distribution component to deliver said content files via the satellite-based content delivery system. 16. The radio network of claim 15, wherein the content provider further comprises an encapsulation component to encapsulate said content files prior to their distribution by the distribution component. 17. The radio network of claim 12, wherein the content provider provides content to different ones of the affiliate radio stations using only a single satellite channel of the satellite-based content delivery system. 18. A radio network origination system, comprising: a user interface displaying a plurality of content file indicators corresponding to files that are to be distributed to affiliates of a radio network, wherein at least some of said content file indicators are associated with a tier indication specifying ones of said affiliates that may require a recording of localized content corresponding to said content file indicator; and a selector tool that, upon a user's selection of a given content file indicator associated with a given tier indication, provides i) a selection that enables a recording of generic content for all affiliates not requiring localized content for said given content file indicator, and ii) one or more selections that enable a recording of localized content for each of the affiliates of a tier corresponding to said given content file indicator. 19. The origination system of claim 18, wherein the selector tool is a drop-down list. 20. The origination system of claim 18, further comprising a process to automatically and sequentially prompt the user to record localized content for each of the affiliates of said tier. 21. A radio network origination system, comprising: a tool to select either a first user interface or a second user interface for recording content files for a plurality of affiliates of a radio network; said first user interface displaying a plurality of content file indicators corresponding to files that are to be distributed to said affiliates, wherein at least some of said content file indicators are associated with a plurality of different files that are to be distributed to different ones of said affiliates, and wherein said content file indicators of said first user interface are selectable by a user to initiate the recording of one or more content files for said affiliates; and said second user interface, configurable to a selected affiliate, displaying a plurality of content file indicators corresponding to files that are to be distributed to the selected affiliate, wherein said content file indicators of said second user interface are selectable by said user to initiate the recording of content files for the selected affiliate. 22. The origination system of claim 21, wherein said first and second user interfaces present said content file indicators similarly. | BACKGROUND A broadcast network, as defined herein, is a network wherein one or more content providers deliver audio, visual, or multimedia content to a plurality of affiliates, each of which broadcasts its received content to a multitude of listeners or viewers. One example of such a broadcast network is a radio network. Traditionally, the content provider in a broadcast network transmits one or more real-time network feeds to each of the affiliates in its network. Each of the affiliates then amplifies and broadcasts its network feed. Each network feed delivers “network content”, and is not localized to the particular market in which an affiliate broadcasts. However, a network feed will typically have a number of predetermined fixed-length “breaks” inserted therein. At each break, the content provider will close one or more relays to switch over to a local broadcast source (or sources). The local broadcast source(s) are then used to air local news, weather, identification information, imaging, spots (i.e., commercials), live feeds and other local content. SUMMARY OF THE INVENTION One aspect of the invention is embodied in a method for operating a radio station. In accordance with the method, the radio station periodically receives content files via a satellite uplink. The received content files are stored. At least some of the stored content files are then retrieved, played and broadcast in accordance with an electronic schedule. Another aspect of the invention is embodied in a method wherein a plurality of affiliate radio stations are provided with content files via a satellite-based content delivery system. Each of the affiliate radio stations is also provided with an electronic schedule that instructs an automation system of the affiliate radio station to retrieve, play and broadcast ones of the content files, thereby generating a near real-time radio broadcast. A third aspect of the invention is embodied in a radio network comprising a plurality of affiliate radio stations and a content provider. The content provider is linked to the plurality of affiliate radio stations via a satellite-based content delivery system, and provides content to each of the affiliates in the form of discrete content files. Yet another aspect of the invention is embodied in a radio network origination system. The system comprises a user interface that displays a plurality of content file indicators corresponding to files that are to be distributed to the affiliates of a radio network. At least some of the content file indicators are associated with a tier indication specifying ones of the affiliates that may require a recording of localized content corresponding to the content file indicator. The system also comprises a selector tool that, upon a user's selection of a given content file indicator associated with a given tier indication, provides i) a selection that enables a recording of generic content for all affiliates not requiring localized content for the given content file indicator, and ii) one or more selections that enable a recording of localized content for each of the affiliates of a tier corresponding to the given content file indicator. A final aspect of the invention is embodied in a radio network origination system. The system comprises a tool to select either a first user interface or a second user interface for recording content files for a plurality of affiliates of a radio network. The first user interface displays a plurality of content file indicators corresponding to files that are to be distributed to the affiliates, and at least some of the content file indicators are associated with a plurality of different files that are to be distributed to different ones of the affiliates. A user may select the content file indicators of the first user interface to initiate the recording of one or more content files for the affiliates. The second user interface is configurable to a selected affiliate, and displays a plurality of content file indicators corresponding to files that are to be distributed to the selected affiliate. A user may select the content file indicators of the second user interface to initiate the recording of content files for the selected affiliate. Other embodiments of the invention are also disclosed. BRIEF DESCRIPTION OF THE DRAWINGS Illustrative and presently preferred embodiments of the invention are illustrated in the drawings, in which: FIG. 1 illustrates a network wherein a broadcast content provider transmits content to each of a number of affiliates via a satellite-based content delivery system; FIG. 2 illustrates the use of a broadcast FORMAT menu item in a user interface at the uplink side of the FIG. 1 network; FIG. 3 illustrates the use of content recording tiers in a graphical user interface (GUI) at the uplink side of the FIG. 1 network; FIG. 4 illustrates a picker-by-affiliate GUI at the uplink side of the FIG. 1 network; and FIG. 5 illustrates a GUI displaying network, local and composite playback schedules at an affiliate of the FIG. 1 network. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 illustrates a network 100 wherein a broadcast content provider 102 transmits content to each of a number of affiliates 106, 108, 110, 112 via a satellite-based content delivery system (i.e., via satellite 104). The content is provided to each of the affiliates in the form of discrete content files. Optionally, one or more content files may be “packaged” or “encapsulated” for delivery via the satellite delivery system. However, what is ultimately received by each of the affiliates is a number of discrete content files. After delivery, an automation system at each affiliate retrieves, plays and broadcasts at least some of its received files in accordance with one or more electronic schedules. In this manner, each affiliate generates a near real-time broadcast. As will be explained in more detail later in this description, each affiliate may be provided with different content files and a different electronic schedule (or schedules). In one embodiment of the network 100, each of the affiliates 106-112 is an affiliate radio station. Software installed at the content provider's site comprises an origination component, an optional encapsulation component, and a distribution component. The origination component is used by operators of the content provider to record and manage content files that are to be transmitted to the affiliates. The encapsulation component then encapsulates files (or sets of files) into streams of data that are compatible for broadband transmission. Finally, the distribution component delivers the encapsulated files to one or more affiliates via a satellite link. By way of example, the origination component may be implemented using the AirForce™ Digital Audio Automation System distributed by MacroMedia (located in Burnsville, Minn.). The encapsulation component may be implemented using one of the IP Encapsulators distributed by Logic Innovations (located in San Diego, Calif.). The distribution component may be implemented using the Fazzt® Digital Delivery System distributed by KenCast (located in Stamford, Conn.). The satellite shown in FIG. 1 may be variously embodied, and in one embodiment is a DVB (digital video broadcast) compliant satellite offering one-way communications for the network (i.e., from the content provider to the affiliates). Although DVB compliant satellites are primarily used for streaming video transmissions, discrete files can also be packaged for DVB delivery. The final element(s) of the network are one or more affiliates. Each affiliate is provided with a satellite receiver and an automation system. In one embodiment, the satellite receiver is the SkyMedia LX2000 Satellite Data Receiver distributed by Telemann (located in San Jose, Calif.). Data files received via an affiliate's satellite receiver are unwrapped and stored. The receipt and storage of files may be facilitated by the KenCast Fazzt® software that was previously mentioned. Once files have been stored, the affiliate's automation system may retrieve, play and broadcast ones of the files in accordance with one or more schedules. By way of example, an affiliate's automation system may be embodied in MacroMedia's AirForce™ software. In adding a new affiliate to the network 100, an automation computer that is preloaded with a number of useful content files (e.g., music files) may be provided to the affiliate. Up-to-date localized content may then be delivered to the affiliate via the affiliate's satellite link to the content provider. The network shown in FIG. 1 offers a number of advantages over other networks. For one, satellite delivery of broadcast content is believed to be the most reliable way to quickly deliver near-real-time broadcast content to a plurality of affiliates. Also, the delivery of content in the form of files, in lieu of a media stream, means that real-time quality can be achieved without the need for real-time delivery and the restrictions associated therewith. For example, it is common for broadcast networks to receive a real-time network feed, with predetermined fixed-length breaks in the feed which an affiliate can (really “has to”) fill with its own content such as spots, imaging, or identification information. If an affiliate is in a small market that cannot fill all of the breaks with original or meaningful content, then filler music, public service announcements, or possibly repetitive information must be used to fill the breaks. Otherwise, dead air is heard by the affiliate's listeners. With the playback of files, breaks can be dynamically resized based on an affiliate's available content. Thus, sloppy network rejoins are eliminated. Further, the playback of files means that aired content is “first generation”, and is not unnecessarily compressed, filtered or relayed before being broadcast to an affiliate's listeners. Typically, first generation content is superior to compressed, filtered or relayed content. Another advantage of the network is that the storage of files at an affiliate's site means that content is always available for playback. If, for some reason, the satellite link is broken and new content is not received by an affiliate, previously downloaded content is still available for playback. Yet another advantage of the network is in the content provider's ability to provide different localized content, and any amount of such localized content, to each of the affiliates. Since content is provided to the affiliates as files, there is no common broadcast “media stream” that all of the affiliates must sync to. Emergency announcements, network spots, and other local content may be addressably sent to one, some or all affiliates for network or locally-controlled playback at a scheduled or unscheduled time. Additionally, the file-centric nature of the network enables a single satellite channel to deliver different sets of content to different affiliates. And, since the content is provided in the form of stored files (and not a real-time media stream), the same content can be played at different times by different affiliates, perhaps to better suit an affiliate's time zone. The above and other advantages offered by the network will be described in more detail in the following more detailed description of the components of the network. As previously mentioned, an origination component (or “system”) is provided on the content provider side of the network and an automation component (or “system”) is provided at each affiliate site. On the uplink side, the origination component provides a means for broadcast personnel (e.g., announcers or “jocks”) to record, schedule and manage content such as music, voice tracks, imaging, network spots, and identification information for playback by the affiliates. On the affiliate side, the automation component may provide a similar means for broadcast personnel to record, schedule and manage content. Alternately, the affiliate automation system may simply display a schedule of what is to be played, with limited or even no ability to edit the schedule (depending on the desired degree of automation and local origination that is requested by a particular affiliate). On the uplink side, an origination component (or “system”) may provide a number of features that enable a jock (or jocks) to more easily record, schedule and manage content. In a radio environment, one useful feature is a “format selection” feature which enables a jock to select a particular format for which he would like to record, schedule or manage content. FIG. 2 illustrates a graphical user interface (GUI) comprising a “broadcast format” menu item. By selecting “System” from the GUI's menu, a jock may select a broadcast format from a drop-down list of available formats. Available formats might include Country, Alternative, Oldies, Adult Contemporary, etc. Upon making a format selection, it is preferable that a jock's origination system make a complete context switch such that file locations, file formats, affiliate lists, logging locations, and possibly even items such as screen colors are updated to reflect the selected format. In this manner, any scheduling, recording, playback or other action undertaken by a jock will be undertaken only for the selected format (and affiliates associated with that format). Upon selecting a format, a jock may be presented with a user interface displaying one or more lists of “content file indicators”, such as file numbers or file names. As shown in FIG. 3, each file number may be mapped to a content type, such as: music, spot, voice track or other content item that might be broadcast by an affiliate. By selecting one of the file numbers, a jock may record or otherwise specify a content item (e.g., a voice track might be recorded, or a music file might be specified) to associate with the file number. Some file numbers might be associated with a single content item, such as a music file that is to be broadcast by all affiliates that broadcast in the selected format. Other file numbers might be associated with multiple content items, such as a plurality of weather updates, each of which is to be distributed to a particular one of a number of affiliates. To provide a means for more easily recording multiple content items for a given file number, the origination system may implement a “tiered” recording feature. A tier can be programmed to specify a predefined subset of affiliates for which unique content (e.g., localized content) needs to be recorded or provided. For example, one tier (Auto_DnLd_LO) could comprise all affiliates for a particular format; another tier could comprise affiliates that need localized content four times an hour (Auto_DnLd—1); and yet another tier could comprise affiliates that need localized content twice an hour (Auto_DnLd—2). One way to implement such tiers is shown in FIG. 3. Upon selecting a file number associated with a tier indication, a jock is prompted with a selector tool such as a drop-down list. If the selector tool is a drop-down list, the tool may list all of the affiliates in the active tier, in addition to a generic indicator representing all affiliates (designated “LO” in FIG. 3). To record content for a tier, the jock may first select the generic indicator and record or specify generic content for all affiliates that do not require specialized or localized content. The jock may then proceed to the first affiliate in the tier, record content specifically tailored to that affiliate, and then repeat this process for all of the remaining affiliates in the tier. Preferably, once a jock begins recording content for the affiliates of a tier, the origination system automatically and sequentially prompts a jock to record content for each of the affiliates in the active tier (i.e., until content has been recorded for each of the affiliates). When a jock selects or is prompted to record localized content for an affiliate (e.g., local weather, or a local “calendar of events”), the jock may be automatically prompted with information that helps him identify and relate to the affiliate. For example, when recording localized content for the affiliates in a tier, the jock may be prompted with a first affiliate's callsign, slogan, city, state, time zone and/or other information related to the affiliate (and if a jock is recording content like weather, he may be prompted with local weather information for the affiliate—possibly retrieved from the internet). When the jock finishes recording the content for that affiliate, the jock may be automatically prompted with similar information for the next affiliate, and so on until content has been recorded for all of the affiliates in the tier. In addition to providing a jock the ability to record content by file number for all affiliates, the origination system may also provide a jock the ability to record files directly into an affiliate's own file system. This may be accomplished using a “file picker-by-affiliate” feature of the origination system (FIG. 4). With file picker-by-affiliate, a jock selects a particular affiliate for which he would like to record voicetracks (e.g., from a drop-down menu). Upon selecting the affiliate, the jock is presented with the files that have been recorded for that affiliate. In one embodiment, the presented files include only those that have been transmitted to the affiliate. Thus, the jock views the same set of files that are available to the affiliate. In another embodiment, the presented files also include files that have been recorded and/or scheduled for delivery to the affiliate. The files presented in a picker-by-affiliate view are preferably presented in accordance with a file structure that is similar to what a jock sees when recording files for multiple affiliates. When a jock selects a file number in a picker-by-affiliate screen, any recording undertaken by the jock is tagged for delivery to the particular affiliate to which the active picker-by-affiliate screen corresponds. Preferably, an uplink's origination system is provided with both the interface shown in FIG. 3 and the interface shown in FIG. 4. Via a toolbar or menu bar such as that which is shown in FIG. 2, a jock may then select either of the interfaces (or alternately switch between them). Upon recording, each content file may be assigned an automatic “kill date”. The purpose of the kill date is to prevent an affiliate from playing an out-of-date file. If for some reason a file with an expired kill date is scheduled to be played (e.g., because an updated file was not received by an affiliate), it will be skipped in lieu of the next file scheduled for playback. Typically, only time-sensitive files such as localized voice tracks (weather, news) need to be assigned kill dates. In one embodiment of the uplink's origination system, files can be sent immediately to the designated affiliate, or stored for later delivery. Certain static files (music and imaging) may be automatically queued on the system for multiple automatic downloads. This ensures that affiliates automatically receive important files. To ensure that files are downloaded to the appropriate affiliates, the origination system may associate each file with an information “token”. A file's associated token may take the form of a text file that describes the source location of the file, its filename, its destination(s) (i.e., one, some or all of the affiliates) and other information. In transferring a file via the satellite, the uplink's distribution system may parse the token to determine where the file needs to be sent. Upon receiving the file, an affiliate may then parse the token to determine where the file should be stored, and what actions, if any, should be taken upon receipt of the file. The origination system at the uplink may also provide one or more means for creating electronic playback schedules for the affiliates. In one embodiment, a single weekly “network schedule” is created for each broadcast format supported by the network (e.g., country, alternative, etc.). The schedules may specify, by file number or file name, each of the files that is to be played back by an affiliate. Typically, a schedule will have a number of “breaks” for which a jock does not specify any content. As will be described in more detail below, these breaks may be filled with spots and other content that is generated by an affiliate. Some portion of these breaks may also be filled by network spots. To enable the airing of the same spot at the same time in each of a number of time zones, one type of file that an automation system might use is a “rotation file”. A rotation file is a file that is programmed to point to other files based on some sort of qualifying event (e.g., day of week, or time of day). A rotation file may also point to other rotation files which, together, form a tree of nested rotation files. For example, a spot can be scheduled to air at the same time in each of a number of time zones by storing the spot as a file referenced by a time-of-day rotator for each of a number of affiliates. The spot can further be aired at a particular day and time by nesting the afore-mentioned time-of-day rotators within day-of-week rotators. On the affiliate side, an automation system needs to be able to store and playback received files. This may be done in accordance with one or more electronic schedules. Preferably, one schedule is provided to an affiliate by the content provider (the network schedule) and another schedule is maintained locally by the affiliate (the local schedule). See FIG. 6. The network schedule contains items such as music, voice tracks, imaging, identification information, and spots provided by the network's content provider. The local schedule may be used by operators at the affiliate to schedule locally-produced content such as local commercials. Although news, weather, music and other content could also be locally-produced and included in the local schedule, it is preferable that requests for this sort of information be faxed to the content provider and recorded and scheduled by the network jock so that a consistent presence is maintained by the affiliate. In order to accommodate multiple playback schedules, an affiliate's automation system can merge the multiple schedules (network and local) to form a composite playback schedule. In one embodiment, a “next hour” of the network and local schedules are merged once each hour. Note that if a common network schedule is provided to affiliates in different time zones, the network schedule may need to be offset with respect to the affiliate's local schedule, prior to merging the network and local schedules. As previously mentioned, when formatting the network schedule, the content provider may insert one or more “breaks” in the schedule. For example, a common radio break format is one break every fifteen minutes (i.e., four breaks an hour). Typically, each of these breaks is nominally 3.0 to 3.5 minutes in length. In one embodiment, the network schedule specifies optional content that can be aired in lieu of each of these breaks. During merger of the network schedule with the local schedule, a determination is made as to whether a minimum quantity of content is available in the local schedule to fill each break. The minimum quantity may be programmable, and in one embodiment may be equal to ninety seconds (or about half the length of a regularly scheduled break). If the minimum quantity of content is available in the local schedule, the content provided in the local schedule is added to the composite schedule, and the optional content (e.g., one or more music files) is left out of the composite schedule. If the minimum quantity of content is not available in the local schedule, the available locally scheduled content, as well as the optional content are added to the composite schedule. Regardless of whether more or less content is provided in the local schedule, and regardless of whether the optional content is added to the composite schedule, the content files that are placed in the composite schedule are aired back-to-back such that no deadtime (silence) is experienced between the various items that are scheduled to be broadcast. Preferably, the hourly network schedule specifies more than sixty minutes of content and breaks. In this manner, additional content is available to fill the end of an hour should i) the affiliate have little or no content for each of its breaks, and ii) the optional content provided for each of the breaks be less than what is needed to fully fill each of the breaks. However, if too much more than sixty minutes of content is specified for a given hour, it becomes difficult for a network jock to estimate the likelihood that affiliates are actually airing the items that are scheduled past the sixty minute mark, and thus a jock may be hesitant to schedule those items again in the near future. As a result, it is believed that a jock should ideally specify about sixty-three minutes of content per hour and, if for some unlikely reason there is a shortage of material for an hour, content from the top of the hour can be re-aired at the bottom of the hour. Excess programming will be “dropped” when the following hour's schedule is loaded. In the past, breaks having irregular or unknown length have caused problems in that a “void” might be left during a break, and filler music of an inconsistent format and fixed duration would have to be plugged in to fill the void. On the flip side, breaks that were too long would have to overlap the playback of content from an unforgiving network feed (or would have to finish airing prior to an affiliate returning to the network feed). Using the schedules and methods for merging schedules described in the above paragraphs, it is very easy for an affiliate to air from 0-4 minutes of locally generated content during a break. Although an affiliate may choose to air more than four minutes of material during a break, doing so creates a risk that one or more breaks may extend into the “next hour”. However, in accordance with a preferred embodiment of schedule merging/loading, only those items that begin to air in the current hour are broadcast by the automation system (and once begun, are broadcast in their entirety). Any item that would not begin to air until the next hour is not aired at all—either by leaving the item out of the current hour's composite schedule, or by ignoring the existence of the item in the composite schedule. In one embodiment, an exception is provided such that contiguous commercial content is allowed to carry over into the “new” hour, which is then loaded only after the final commercial-designated program element has been aired. Some useful features that are provided by flexible breaks are: 1) an affiliate can sell spots of any length, and is not limited to selling precisely timed :30 or :60 second spots that neatly fit within a prescribed break window, and 2) an affiliate can overlap or otherwise merge, edit or position spots, since changing the length of material that is available for a break will not result in dead air, silence or overruns at the end of the break. If an affiliate would like a network jock to record material for a break, they can call in, fax or email a request for such content to the network's content provider. As partly described above, an affiliate's automation system may provide a greater or lesser degree of automation for any particular affiliate. One option that some affiliates will want to take advantage of is local “live” broadcasts, or the airing of live network broadcasts such as sports games, on-site publicity events, or press conferences. Such live events may be accommodated using standard relay closures. At a desired point in a network schedule, an affiliate's operator may simply close a desired relay connection or select a different Network configuration setting to “switch over” to a live feed. At the end of a live feed, an affiliate would previously have had to worry about timing a network rejoin. However, since the network described herein is a not a real-time network, the automation system described herein can ease these network rejoins. In one embodiment, an affiliate's automation system provides a “Sync” button as part of its GUI. Upon clicking the Sync button, the automation system determines a sync point in the current hour's composite schedule that is close to the current time in the hour. The sync point may be before or after the sync time. Preferably, the current hour's composite schedule continues to load (but not play) during live broadcasts so that a sync point can be determined relatively quickly. It does not matter if the sync point is before or after the sync time, because as previously stated, only those content items that begin to air in the current hour are broadcast, and any items that do not begin to air in the current hour are dropped as the next hour's schedule begins to play. To provide redundancy, and to offer a low cost means of implementing a return link to a network's content provider, each affiliate may be equipped with an internet connection. If a satellite delivery channel breaks down, most localized content can be alternately provided to an affiliate via the internet connection, especially if the internet connection is a broadband connection. As another redundancy, the network may be programmed to automatically and periodically (e.g., once a week) resend files that it was asked to send within a prior time frame (e.g., the last three weeks). In one embodiment, this feature is used to resend all music files, but not time-sensitive localized content. Note that even if the above redundant delivery processes fail, it is very likely that an affiliate will still continue to broadcast. This is because, at any given time, a large amount of prior and future broadcast content is locally stored by the affiliate. This is not the case with real-time delivery networks. While illustrative and presently preferred embodiments of the invention have been described in detail herein, it is to be understood that the inventive concepts may be otherwise variously embodied and employed, and that the appended claims are intended to be construed to include such variations, except as limited by the prior art. | <SOH> BACKGROUND <EOH>A broadcast network, as defined herein, is a network wherein one or more content providers deliver audio, visual, or multimedia content to a plurality of affiliates, each of which broadcasts its received content to a multitude of listeners or viewers. One example of such a broadcast network is a radio network. Traditionally, the content provider in a broadcast network transmits one or more real-time network feeds to each of the affiliates in its network. Each of the affiliates then amplifies and broadcasts its network feed. Each network feed delivers “network content”, and is not localized to the particular market in which an affiliate broadcasts. However, a network feed will typically have a number of predetermined fixed-length “breaks” inserted therein. At each break, the content provider will close one or more relays to switch over to a local broadcast source (or sources). The local broadcast source(s) are then used to air local news, weather, identification information, imaging, spots (i.e., commercials), live feeds and other local content. | <SOH> SUMMARY OF THE INVENTION <EOH>One aspect of the invention is embodied in a method for operating a radio station. In accordance with the method, the radio station periodically receives content files via a satellite uplink. The received content files are stored. At least some of the stored content files are then retrieved, played and broadcast in accordance with an electronic schedule. Another aspect of the invention is embodied in a method wherein a plurality of affiliate radio stations are provided with content files via a satellite-based content delivery system. Each of the affiliate radio stations is also provided with an electronic schedule that instructs an automation system of the affiliate radio station to retrieve, play and broadcast ones of the content files, thereby generating a near real-time radio broadcast. A third aspect of the invention is embodied in a radio network comprising a plurality of affiliate radio stations and a content provider. The content provider is linked to the plurality of affiliate radio stations via a satellite-based content delivery system, and provides content to each of the affiliates in the form of discrete content files. Yet another aspect of the invention is embodied in a radio network origination system. The system comprises a user interface that displays a plurality of content file indicators corresponding to files that are to be distributed to the affiliates of a radio network. At least some of the content file indicators are associated with a tier indication specifying ones of the affiliates that may require a recording of localized content corresponding to the content file indicator. The system also comprises a selector tool that, upon a user's selection of a given content file indicator associated with a given tier indication, provides i) a selection that enables a recording of generic content for all affiliates not requiring localized content for the given content file indicator, and ii) one or more selections that enable a recording of localized content for each of the affiliates of a tier corresponding to the given content file indicator. A final aspect of the invention is embodied in a radio network origination system. The system comprises a tool to select either a first user interface or a second user interface for recording content files for a plurality of affiliates of a radio network. The first user interface displays a plurality of content file indicators corresponding to files that are to be distributed to the affiliates, and at least some of the content file indicators are associated with a plurality of different files that are to be distributed to different ones of the affiliates. A user may select the content file indicators of the first user interface to initiate the recording of one or more content files for the affiliates. The second user interface is configurable to a selected affiliate, and displays a plurality of content file indicators corresponding to files that are to be distributed to the selected affiliate. A user may select the content file indicators of the second user interface to initiate the recording of content files for the selected affiliate. Other embodiments of the invention are also disclosed. | 20040120 | 20080812 | 20050721 | 58407.0 | 1 | REGO, DOMINIC E | SYSTEMS, METHODS AND APPARATUS FOR OPERATING A BROADCAST NETWORK | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,761,542 | ACCEPTED | Apparatus and method for initiating a combustion reaction with solid state solid fuel | A method is provided for initiating and sustaining a combustive reaction in a solid fuel. The method includes generating at least one pulsed optical signal and directing the pulsed optical signal to a plurality of ignition points within at least one combustion chamber containing a solid fuel. The pulsed optical signal is generated by an optical source, e.g. a laser pump, and modulated using an intensity profiler. The intensity profiler modulates the pulsed optical signal to initially have a first peak power sufficient to initiate a combustive reaction in a solid fuel. The intensity profiler further modulates the pulsed optical signal to subsequently have a second peak power sufficient to sustain the combustive reaction until sufficient exothermic energy is released by the combustive reaction to make the reaction self-sustaining. | 1. A method for initiating and sustaining a combustive reaction in a solid fuel, said method comprising: generating at least one pulsed optical signal; directing the pulsed optical signal to a plurality of ignition points within at least one combustion chamber containing a solid fuel; modulating the pulsed optical signal to initially have a first peak power sufficient to initiate a combustive reaction in a solid fuel; and modulating the pulsed optical signal to subsequently have a second peak power sufficient to sustain the combustive reaction once the combustive reaction is initiated. 2. The method of claim 1, wherein directing the pulsed optical signal comprises utilizing an optical fiber coupler including a plurality of optical fibers to transmit the pulsed optical signal to the plurality of ignition points. 3. The method of claim 1, wherein generating at least one pulsed optical signal comprises generating a plurality of pulsed optical signals. 4. The method of claim 3, wherein directing the pulsed optical signal comprises directing each of the pulsed optical signals to at least one of the multiple ignition points. 5. The method of claim 1, wherein generating at least one pulsed optical signal comprises generating the pulsed optical signal to have a wavelength sufficiently short so that absorption of the pulsed optical signal by the solid fuel leads to molecular disassociation of the solid fuel. 6. The method of claim 1, wherein generating at least one pulsed optical signal comprises generating the pulsed optical signal to have a duration sufficiently short so that the signal will have sufficient energy to generate the combustive reaction of the solid fuel. 7. The method of claim 1, wherein modulating the pulsed optical signal to initially have a first peak power comprises modulating the pulsed optical signal to have a first portion having a peak power sufficient to initiate a combustive reaction in a solid fuel. 8. The method of claim 7, wherein modulating the pulsed optical signal to have a second peak power comprises modulating the pulsed optical signal to have a second portion having a peak power sufficient to sustain the combustive reaction until sufficient exothermic energy is released by the combustive reaction to make the reaction self-sustaining. 9. The method of claim 1, wherein modulating the pulsed optical signal to initially have a first peak power comprises modulating a plurality of pulsed optical signals wherein a first pulsed optical signal has a peak power sufficient to initiate a combustive reaction in a solid fuel. 10. The method of claim 9, wherein modulating the pulsed optical signal to have a second peak power comprises modulating at least one second pulsed optical signal generated subsequent to the first pulsed optical signal to have a peak power sufficient to sustain the combustive reaction until sufficient exothermic energy is released by the combustive reaction to make the reaction self-sustaining. 11. The method of claim 10, wherein generating at least one pulsed optical signal comprises generating the first pulsed optical signal a predetermined time prior to generating the second pulsed optical signal so that all the energy of the second pulsed optical signal will be uniformly absorbed by the solid fuel without causing undesirable optical processes to interfere with the initiation of the combustive reaction. 12. The method of claim 1, wherein modulating the pulsed optical signal comprises modulating the pulsed optical signal in accordance with the equation: Icr={mcEI(1+(ωτ)2]/[2TTe2τ]}[g+1/τρ loge(ρcr/ρ0)] where ρcr is the critical electron number for breakdown, τρ is the laser pulse width; m, e, c are the electron constants; ω is the optical field frequency; EI is the ionization energy of the solid fuel or an oxidizer; τ is the momentum transfer collision time; g is the electron loss rate; and ρ0 is the initial electron density. 13. A propulsion system comprising: at least one combustion chamber adapted to receive a solid fuel and oxidizer mixture; at least one optical source adapted to generate at least one pulsed optical signal; an intensity profiler adapted to modulate the pulsed optical signal to have a first peak power sufficient to initiate a combustive reaction of the solid fuel and a second peak power sufficient to sustain the combustive reaction until sufficient exothermic energy is released by the combustive reaction to make the reaction self-sustaining; and an optical fiber coupler adapted to direct the pulsed optical signal to a plurality of ignition points within the combustion chamber. 14. The system of claim 13, wherein the optical fiber coupler comprises an optical splitter adapted to divide the pulsed optical signal into a plurality of pulsed optical signal transmit via a plurality of optical fibers to the plurality of ignition points. 15. The system of claim 13, wherein the optical fiber coupler comprises a bundle of optical fibers interconnecting the optical source and the combustion chamber and adapted to direct the pulsed optical signal to the plurality of ignition points. 16. The system of claim 13, wherein the intensity profiler is further adapted to modulate the pulsed optical signal to have a first portion having a peak power sufficient to initiate a combustive reaction in a solid fuel. 17. The system of claim 16, wherein the intensity profiler is further adapted to modulate the pulsed optical signal to have a second portion having a peak power sufficient to sustain the combustive reaction until sufficient exothermic energy is released by the combustive reaction to make the reaction self-sustaining. 18. The system of claim 13, wherein the intensity profiler is further adapted to modulate a first pulsed optical signal generated by the optical source to have a peak power sufficient to initiate a combustive reaction in a solid fuel. 19. The system of claim 18, wherein the intensity profiler is further adapted to modulate at least one second pulsed optical signal generated subsequent to the first signal to have a peak power sufficient to sustain the combustive reaction until sufficient exothermic energy is released by the combustive reaction to make the reaction self-sustaining. 20. The system of claim 19, wherein the optical source is further adapted to generate the first pulsed optical signal a predetermined time prior to generating the second pulsed optical signal so that all the energy of the second pulsed optical signal will be uniformly absorbed by the solid fuel without causing undesirable optical processes to interfere with the initiation of the combustive reaction. 21. The system of claim 20, wherein the predetermined time is less than approximately ten nanoseconds. 22. The system of claim 13, wherein the intensity profiler is further adapted to modulate the pulsed optical signal in accordance with the equation: Icr={mcEI(1+(ωτ)2]/[2TTe2τ]}[g+1/τρ loge(ρcr/ρ0)] where ρcr is the critical electron number for breakdown, τρ is the laser pulse width; m, e, c are the electron constants; ω is the optical field frequency; EI is the ionization energy of the solid fuel or an oxidizer; τ is the momentum transfer collision time; g is the electron loss rate; and ρ0 is the initial electron density. 23. The system of claim 13, wherein the optical source is further adapted to generate the pulsed optical signal to have a wavelength sufficiently short so that absorption of the pulsed optical signal by the solid fuel leads to molecular disassociation of the solid fuel. 24. The system of claim 23, wherein the wavelength is shorter than approximately 300 nanometers. 25. The system of claim 13, wherein the optical source is further adapted to generate the pulsed optical signal to have a duration sufficiently short so that the signal will have sufficient energy to generate the combustive reaction of the solid fuel. 26. The system of claim 25, wherein the duration of the duration is less than approximately three nanoseconds. 27. A method for initiating and sustaining a combustive reaction of a solid fuel contained in a combustion chamber, said method comprising: generating at least one pulsed optical signal; directing the pulsed optical signal to a plurality of ignition points within the combustion chamber; initiating a combustive reaction of the solid fuel utilizing the pulsed optical signal modulated to have a first peak power sufficient to initiate a combustive reaction in a solid fuel; and sustaining the combustive reaction of the solid fuel utilizing the pulsed optical signal modulated to have a second peak power sufficient to sustain the combustive reaction until sufficient exothermic energy is released by the to make the reaction self-sustaining. 28. The method of claim 27, wherein directing the pulsed optical signal comprises utilizing an optical fiber coupler including a plurality of optical fibers to transmit the pulsed optical signal to the plurality of ignition points. 29. The method of claim 27, wherein generating at least one pulsed optical signal comprises generating a plurality of pulsed optical signals. 30. The method of claim 29, wherein directing the pulsed optical signal comprises directing each of the pulsed optical signals to at least one of the multiple ignition points. 31. The method of claim 27, wherein generating at least one pulsed optical signal comprises generating the pulsed optical signal to have a wavelength sufficiently short so that absorption of the pulsed optical signal by the solid fuel leads to molecular disassociation of the solid fuel. 32. The method of claim 27, wherein generating at least one pulsed optical signal comprises generating the pulsed optical signal to have a duration sufficiently short so that the signal will have sufficient energy to generate the combustive reaction of the solid fuel. 33. The method of claim 27, wherein initiating a combustive reaction comprises modulating the pulsed optical signal to have a first portion having the first peak power sufficient to initiate a combustive reaction in a solid fuel. 34. The method of claim 33, wherein sustaining the combustive reaction comprises modulating the pulsed optical signal to have a second portion having the second peak power sufficient to sustain the combustive reaction until sufficient exothermic energy is released by the combustive reaction to make the reaction self-sustaining. 35. The method of claim 27, wherein initiating a combustive reaction comprises modulating a plurality of pulsed optical signals wherein a first pulsed optical signal has the first peak power sufficient to initiate a combustive reaction in a solid fuel. 36. The method of claim 35, wherein sustaining the combustive reaction comprises modulating at least one second pulsed optical signal generated subsequent to the first pulsed optical signal to have a peak power sufficient to sustain the combustive reaction until sufficient exothermic energy is released by the combustive reaction to make the reaction self-sustaining. 37. The method of claim 36, wherein the method further comprises generating the first pulsed optical signal a predetermined time prior to generating the second pulsed optical signal so that all the energy of the second pulsed optical signal will be uniformly absorbed by the solid fuel without causing undesirable optical processes to interfere with the initiation of the combustive reaction. 38. The method of claim 27, wherein initiating and sustaining the combustive reaction comprises modulating the pulsed optical signal in accordance with the equation: Icr={mcEI(1+(ωτ)2]/[2TTe2τ]}[g+1/τρ loge(ρcr/ρ0)] where ρcr is the critical electron number for breakdown, τρ is the laser pulse width; m, e, c are the electron constants; ω is the optical field frequency; EI is the ionization energy of the solid fuel or an oxidizer; τ is the momentum transfer collision time; g is the electron loss rate; and ρ0 is the initial electron density. | CROSS REFERENCE TO RELATED APPLICATIONS This application is related to copending U.S. patent application Ser. No. 10/007,994, titled Apparatus And Method For Initiating A Combustion Reaction With Slurry Fuel, filed on Nov. 8, 2001. FIELD OF THE INVENTION The present invention relates to fuel ignition and, more specifically, to optically initiated chemical reactions to establish combustion in a propulsion engine using storable high-density solid state solid fuels. BACKGROUND OF THE INVENTION Solid state solid fuels are propulsion fuels that are in solid form when stored at ambient temperatures. As with most any material that is in a solid phase, the mass density and energy density of the fuel is much high in the solid state than when in a liquid or gas phase. As a result, the specific impulse and thrust potential from the fuel is much higher in solid state solid fuels, herein also referred to as solid fuels. However, fuels are more difficult to ignite using traditional electric spark or torch-ignition techniques when in a solid state than when in a liquid or gas form. Therefore, it would be highly desirable to provide an efficient and sufficiently simple method of initiating a combustive reaction in a solid fuel. SUMMARY OF THE INVENTION In a preferred implementation, the present invention provides a method for initiating and sustaining a combustive reaction in a solid fuel. The method includes generating at least one pulsed optical signal and directing the pulsed optical signal to a plurality of ignition points within at least one combustion chamber containing a solid fuel. The pulsed optical signal is generated by an optical source, e.g. a laser pump, and modulated using an intensity profiler. The intensity profiler modulates the pulsed optical signal to initially have a first peak power sufficient to initiate a combustive reaction in a solid fuel. The intensity profiler further modulates the pulsed optical signal to subsequently have a second peak power sufficient to sustain the combustive reaction until sufficient exothermic energy is released by the combustive reaction to make the reaction self-sustaining. In another preferred implementation the present invention provides a propulsion system including at least one combustion chamber. The combustion chamber receives a solid fuel and oxidizer mixture used to provide propulsion by igniting the mixture. The propulsion system additionally includes at least one optical source for generating at least one pulsed optical signal used to ignite and sustain a combustive reaction of the solid fuel and oxidizer mixture. An optical fiber coupler connected to the optical source directs the pulsed optical signal to a plurality of ignition points within the combustion chamber. Furthermore, the propulsion system includes an intensity profiler adapted to modulate the pulsed optical signal to have a first peak power sufficient to initiate the combustive reaction. The intensity profiler further modulates the pulsed optical signal to have a second peak power sufficient to sustain the combustive reaction. The pulsed optical signal sustains the combustive reaction until sufficient exothermic energy is released by the combustive reaction to make the reaction self-sustaining. The features, functions, and advantages of the present invention can be achieved independently in various embodiments of the present inventions or may be combined in yet other embodiments. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: FIG. 1 is a block diagram of the optically initiated propulsion system of the present invention; FIG. 2 is a graphical representation of a light pulse over time according to a preferred embodiment of the present invention; FIG. 3 is a graphical representation of a first and second light pulse over time according to another preferred embodiment of the present invention; and FIG. 4 is a graphical representation of the method of optical ignition according to the present invention. Corresponding reference numerals indicate corresponding parts throughout the several views of drawings. DETAILED DESCRIPTION OF THE INVENTION The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application or uses. Additionally, the advantages provided by the preferred embodiments, as described below, are exemplary in nature and not all preferred embodiments provide the same advantages or the same degree of advantages. With initial reference to FIG. 1, an optically initiated propulsion system 10 according to the present invention is illustrated. The propulsion system 10, shown operatively disposed in a vessel 12, includes an optical source 20 such as a laser for producing coherent light. A fiber coupler 50, comprising one or more optical fiber, optically connects optical source 20 with a solid fuel and oxidizing agent mixture 90, also referred to herein as solid fuel/oxidizer mixture 90, in a combustion chamber 70. An intensity profiler 30 and optical wavelength filter 40 are incorporated between optical source 20 and fiber coupler 50. A fiber to chamber coupler 60 is used to interconnect the fiber coupler 30 with the solid fuel/oxidizer mixture 90. The optical initiation of combustion of the solid fuel/oxidizer mixture 90 yields a mixture of partially dissociated air and chemically cracked fuel 60. In a preferred embodiment, the fiber coupler 50 comprises a collection or series of optical fibers in a bundle. The fibers interconnect with multiple ignition positions within a single combustion chamber 70. Having multiple ignition positions with a single combustion chamber 70 increases the ease of igniting the solid fuel and the ease in sustaining the combustive reaction. Alternatively, the optical fibers interconnect with multiple combustion chambers 70 within the vessel 12. The collection of fibers may be designed in several ways. In one form, each optical fiber connects with a separate optical source 20. Each fiber directs the optical energy to a single ignition point. In an alternative form, the fiber coupler 50 includes an optical splitter adapted to receive a single pulsed optical signal from the optical source 20 and divide the signal into a plurality of pulsed optical signals. The optical splitter splits the optical energy and directs the optical energy optical splitter can be any suitable optical splitter, for example, an active coupler in which an optical pulse enters the coupler and is optically switched to one of the output optical fibers. In this manner, the optical energy can be serially directed to each of the output fibers. The propulsion produced by any engine is the result of an exothermic chemical reaction. In order to ignite the engine, the activation energy of the chemical reaction must be overcome. As with any chemical reaction, the microscopic behavior is dictated by quantum mechanical behaviors. The inherent stochastic nature of the quantum behaviors implies that there is a probability distribution associated with the ignition. In a gas phase ignition, the activation energy is overcome by applying energies well above a threshold value. Typically, for solid fuels, different areas have different threshold energies. Small differences in the chemical constituents will also change the propagation of a flame front, once ignition is achieved. This can lead to local flameouts, whose location cannot be determined ahead of time. These difficulties can be mitigated by increasing the number of ignition points within the solid fuel structure, as described above. In an alternative preferred embodiment, to assure ignition, multiple optical signals can be sent to one or more ignition points. The characteristics of laser light emitted from the optical source 20 will now be described in greater detail. Characteristics associated with laser light must be optimized for optically initiating combustion. These characteristics can include laser pulse duration, pulse intensity envelope shape, laser energy within the envelope, peak optical power, center wavelength and frequency bandwidth. Optimization of these characteristics involves selecting the characteristics to assure that maximum coupling of optical energy into the molecular bonds of materials in the propulsion mixture. In the case of a solid fuel, additional constraints need to be imposed. For example, the laser light wavelength must be short enough so that absorption via linear or nonlinear mechanisms leads to molecular dissociation of fuel, oxidizer or both. The shape of the intensity envelope can control not only the amount, but also the deposition speed of energy into the internal molecular energy states. The implication is that the light must be in the ultraviolet range of the spectrum, preferably shorter than 300 nanometers. In most practical applications, a diode-pumped solid state laser will be used as optical source 20 because of its mechanical robustness. The light from these lasers, however, will typically be in the near infrared, requiring nonlinear optical conversion to shorter wavelengths. After the conversion is accomplished, there will be remnants of longer wavelengths in the laser light. Before introduction into the fiber coupler 50, optical wavelength filter 40, or an equivalent filtering medium, removes any residual light at longer wavelengths. For ignition to occur in a solid fuel 92, a balance must be reached between the light energy absorbed into the fuel/oxidizer mixture 90 and the volume of the mixture that is excited. In other words, the absorbed energy density of the mixture is as important as the absorbed energy itself. If too much energy is deposited in a highly localized volume of solid fuel 92, it will not be sufficient to allow the exothermic chemical reaction to reach a self-initiating condition. In normal gas or liquid phase fuels, nonlinear effects are highly independent of absolute position in the volume because the local density fluctuations do not affect the local optical susceptibility. However, for solid fuels, tailoring the optical intensity is very important. This is because the interaction with the solid fuel/oxidizer mixture 90 will begin with a nonlinear optical absorption. Thus, the light emitted from optical source 20 is preferably in a pulsed format so that high peak laser powers can be generated. Generally, the peak power associated with a laser generated pulse is equal to the energy in the pulse divided by the duration of the pulse. As an example, a laser pulse may only contain 1 millijoule of energy emanated from a one milliwatt laser in one second. This does not represent a large amount of energy. However, if that one millijoule of energy is contained within a pulse that is, for example, one to three nanoseconds in duration, then the peak power is one Gigawatt. Even though the pulse duration is short, the surrounding medium will react to the laser pulse as if it were a one Gigawatt power laser, although the effect will only last the duration of the laser pulse. In this manner, sufficient energy in each pulse generates a peak power that is associated with the onset of nonlinear optical behavior, for example approximately 1-2 Megawatts. Additionally, the pulse shape and/or format of the optical signal emitted from the optical source 20 is modulated by the intensity profiler 30 for optimized interaction with the high densities associated with the solid fuel 92. Because the initial absorption volume in the solid fuel 92 will be small due to the higher density, it will be advantageous to output an optical pulse from the optical source 20 having a high peak power at the beginning of the pulse and a lower peak power during a later portion of the pulse. Also, the nature of the solid fuel 92 will lead to larger density fluctuations that cause changes in the local absolute value of an electric field associated with the light signal emitted from optical source 20. In any medium, the local electric field is due to both an applied field and a field induced in the medium. The nonlinear optical process is dependent on this local field. Consequently, any nonlinear optical process may begin at slightly different intensity levels at different locations within the solid fuel/oxidize mixture 90. Further yet, because of the high density of the solid fuel 92, the solid fuel 92 will be generally less transparent than gas or liquid materials. Therefore, as a result of the optical opacity of the solid fuel 92, the solid fuel 92 will absorb a high percentage of the laser light emitted from optical source 20, disproportionate to the light absorbed by the surrounding media. More specifically, the lower transparency results in a higher degree of light absorption that aids in coupling, i.e. routing, the optical energy into internal energy and consequently heating of the fuel/oxidizer mixture 90. The dissociation of the molecules in both the solid fuel 92 and the oxidizer 94 is associated with light wavelengths in the ultraviolet shorter than 300 nm. The association with the light wavelengths is due to the fact that the electronic excitations leading to the dissociation of the molecules characteristically occur with internal energies that exceed 3 electron-volts (ev). The internal heating of molecules, that is, the excitation of energy level corresponding to vibration motion, is associated with light wavelengths in the infrared, longer than 900 nm. Furthermore, the high absorption creates an unusual situation wherein molecular dissociation and molecular heating processes are simultaneously enhanced. More specifically, the molecular dissociation and molecular heating processes proceed more quickly and at higher efficiency levels due to the high absorption. For this reason, the intensity of the laser signal emitted from the optical source 20 is profiled to have a high peak power at the initiation of ignition, when molecular dissociation dominates the physical process, and a lower power level after ignition is established, when internal heating dominates the process. Thus, the internal heating sustains the combustive reaction until sufficient exothermic energy is released to make the reaction self-sustaining. The intensity profiler 30 will now be described in greater detail. It will be appreciated by those skilled in the art that the location of intensity profiler 30 is merely exemplary and may be positioned subsequent to optical wavelength filter 40. In a preferred embodiment, shown in FIG. 2, the intensity profiler 30 modulates the optical signal emitted from the optical source 20 such that the signal has a high initial peak power at its leading edge and a lower peak power during the remainder of the pulse. The energy level at the leading edge of the signal is sufficient to initiate a combustive reaction in, i.e. ignite, the solid fuel/oxidizer mixture 90. Subsequently, the energy level during the remainder of the signal is sufficient to sustain the combustive reaction occurring in the solid fuel/oxidizer mixture 90 until sufficient exothermic energy is released to make the reaction self-sustaining. In another preferred embodiment, shown in FIG. 3, the optical source 20 emits two or more pulses. The intensity profiler 30 modulates the pulses such that an initial pulse has high peak power and a predetermined duration and pulses subsequent to the initial pulse have a lower peak power and a predetermined duration. The pulses are emitted from the optical source in a temporally serial fashion. The energy level of the initial pulse is sufficient to initiate a combustive reaction in, i.e. ignite, the solid fuel/oxidizer mixture 90. Subsequently, the energy level during the subsequent pulse(s) is sufficient to sustain the combustive reaction occurring in the solid fuel/oxidizer mixture 90 until sufficient exothermic energy is released to make the reaction self-sustaining. This pulsing sequence can be used one time in an engine with steady flow, or it can be used multiple times and be regulated to create a desired sequence of ignitions. When used multiple times at multiple points of ignition, a variety of pulse sequences and the ability to switch the pulses to different areas, allows the exact ignition timing sequence can be controlled. Several locations may be ignited simultaneously or specific physical locations can be ignited before other locations. For example, it may be advantageous to ignite the center of the solid fuel/oxidizer mixture 90 first, with the ignition of the outer areas being ignited later. In this manner, the ignition flame front from the first ignition area will reach other areas of the solid fuel/oxidizer mixture 90 and the subsequent ignition pulses will arrive at the same time as the ignition flame front. As a result, the exothermic energy of the flame will coincide with the optical energy, leading to a fuel state that contains more internal molecular energy, increasing the probability for sustained ignition. In each embodiment, the initial high peak power will quickly generate a micro-plasma that is opaque to most laser wavelengths. The time elapsed between the high and low power excitations is short enough such that all the energy of the lower peak power will be uniformly absorbed without causing other undesirable nonlinear optical processes to interfere with the optical initiation. For example, the time between the high and lower power excitations is preferably less than ten nanoseconds, but possibly as long as 100 nanoseconds. The ignition of the solid fuel/oxidizer mixture 90 using optical source 20 will now be described in greater detail. The equation governing the optical intensity to drive the optical breakdown is given by: Icr={mcEI(1+(ωτ)2]/[2TTe2τ]}[g+1/τρ loge(ρcr/ρ0)] where ρcr is the critical electron number for breakdown, τρ is the laser pulse width; m, e, c are the electron constants; ω is the optical field frequency; EI is the ionization energy of the fuel 92 or the oxidizer 94; τ is the momentum transfer collision time; g is the electron loss rate; and ρ0 is the “initial” electron density. Although this depends on the particular characteristics of the solid fuel/oxidizer mixture 90, the propulsion system 10 is designed to deliver the level of optical intensity into the combustion chamber 70, as dictated by the equation. The optical energy delivered in accordance with the equation is the pulsed optical energy described above that is delivered into the combustion chamber 70 to initiate and sustain the propulsion reaction. Once a finite number of solid fuel 92 and/or oxidizer 94 molecules have been dissociated, the resulting physical state is an optically opaque medium. The dissociation occurs when sufficient energy is absorbed by the molecular bond such that the electrons associated with that bond can no longer bond the atoms together. This process is very fast, for example, by the end of a one nanosecond pulse, the dissociations have already occurred. All the subsequent energy in the laser pulse is absorbed into this medium. Additionally, the optical spot size of the optical signal is a function of the intensity at which the fuel oxidizer molecules break down. For example, the optical intensity is increased by using a smaller optical spot size, therefore, the spot size will affect the optical intensity and consequently the strength of the nonlinear optical absorption. Thus, the absorption leads to the molecular dissociation necessary for ignition of the solid fuel/oxidizer mixture 90. The breaking down of solid fuel 92 is generally simple because metal particles in the solid fuel 92 both increase optical absorption and enhance the optical nonlinearity of the media. For example, peak powers of approximately 1-2 Megawatts at ultraviolet wavelengths, preferably less than 300 nanometers, will be sufficient to initiate breakdown, with the breaking down beginning to occur near the densest volumes of the solid fuel 92. Internal energies sufficient to drive the mixture into a self-sustaining condition can then be generated with a lower power portion of the same pulse or with a lower power second laser pulse to complete the initiation of the reaction. The initiation is complete when the exothermic energy of the reaction is sufficient to continue driving the reaction, i.e. the reaction is self-sustaining. This self-sustaining chemical reaction is the combustion reaction that produces the engine propulsion. Generally, optical delivery systems, such as optical source 20, can generate laser energies on the order of 10 millijoules. Fiber coupler 50 is adapted to transmit pulses that simultaneously have a high peak power and a short wavelength. Preferably, fiber coupler 50 includes one or more non-solarizing optical fibers that support the high peak power and short wavelength requirements and transmit the pulse(s) with substantially no loss of energy or intensity. For example, the absorption volume in the solid fuel 92 can be on the order of approximately 100 to 115 cubic microns. A corresponding energy density of approximately 5 to 15 GJ/cubic meter can then be produced to initiate combustion. Through the use of non-linear absorption, enough free electrons are created within a high intensity focus region of the solid fuel/oxidizer mixture 90 to allow the solid fuel/oxidizer mixture 90 to take on the absorption characteristic of plasma. Generally, plasma ranges from highly absorbing to completely opaque and allows for a finite fraction of the pulse energy to be absorbed by the medium, e.g. the solid fuel/oxidizer mixture 90. In addition, in the high density of the solid fuel 92 enhances the optical nonlinearity of the medium. The nonlinearity of the solid fuel/oxidizer mixture 90 is used to enhance the absorption process that leads to the initiation of the chemical reaction. The resulting mixture 80 after ignition will be comprised of partially dissociated air and chemically cracked fuel. The mixture includes molecular and atomic oxygen, an array of hydrocarbon fragments, low molecular weight hydrocarbon compounds and some remaining parent carrier fuel. FIG. 4 is a flow chart 200 illustrating a method of initiating and sustaining a combustive reaction in the solid fuel/oxidizer mixture 90, in accordance with a preferred embodiment of the present invention. To begin the combustive reaction, the optical source 20 generates at least one very short pulsed optical signal, as indicated at 202. Substantially simultaneously, the solid fuel/oxidizer mixture 90 is provided in combustion chamber 70, as indicated at 204. The intensity profiler 30 profiles, i.e. modulates, the optical signal(s) to initially have a high peak power that is sufficient to initiate a combustive reaction in the solid fuel/oxidizer mixture 90, as indicated at 206. The fiber coupler 50 directs the optical signal(s) to a plurality of ignition points within the combustion chamber 70, as indicated at 208. After the combustive reaction is initiated the intensity profiler 30 profiles the optical signal(s) to have a lower peak power, as indicated at 210. The lower peak power coupled with the exothermic energy generated by the combustive reaction establishes a self-sustaining combustive reaction of the solid fuel/oxidizer mixture 90 that occurs until the solid fuel/oxidizer mixture is substantially completely burned, i.e. disassociated, as indicated at 212. While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>Solid state solid fuels are propulsion fuels that are in solid form when stored at ambient temperatures. As with most any material that is in a solid phase, the mass density and energy density of the fuel is much high in the solid state than when in a liquid or gas phase. As a result, the specific impulse and thrust potential from the fuel is much higher in solid state solid fuels, herein also referred to as solid fuels. However, fuels are more difficult to ignite using traditional electric spark or torch-ignition techniques when in a solid state than when in a liquid or gas form. Therefore, it would be highly desirable to provide an efficient and sufficiently simple method of initiating a combustive reaction in a solid fuel. | <SOH> SUMMARY OF THE INVENTION <EOH>In a preferred implementation, the present invention provides a method for initiating and sustaining a combustive reaction in a solid fuel. The method includes generating at least one pulsed optical signal and directing the pulsed optical signal to a plurality of ignition points within at least one combustion chamber containing a solid fuel. The pulsed optical signal is generated by an optical source, e.g. a laser pump, and modulated using an intensity profiler. The intensity profiler modulates the pulsed optical signal to initially have a first peak power sufficient to initiate a combustive reaction in a solid fuel. The intensity profiler further modulates the pulsed optical signal to subsequently have a second peak power sufficient to sustain the combustive reaction until sufficient exothermic energy is released by the combustive reaction to make the reaction self-sustaining. In another preferred implementation the present invention provides a propulsion system including at least one combustion chamber. The combustion chamber receives a solid fuel and oxidizer mixture used to provide propulsion by igniting the mixture. The propulsion system additionally includes at least one optical source for generating at least one pulsed optical signal used to ignite and sustain a combustive reaction of the solid fuel and oxidizer mixture. An optical fiber coupler connected to the optical source directs the pulsed optical signal to a plurality of ignition points within the combustion chamber. Furthermore, the propulsion system includes an intensity profiler adapted to modulate the pulsed optical signal to have a first peak power sufficient to initiate the combustive reaction. The intensity profiler further modulates the pulsed optical signal to have a second peak power sufficient to sustain the combustive reaction. The pulsed optical signal sustains the combustive reaction until sufficient exothermic energy is released by the combustive reaction to make the reaction self-sustaining. The features, functions, and advantages of the present invention can be achieved independently in various embodiments of the present inventions or may be combined in yet other embodiments. | 20040121 | 20090217 | 20050721 | 92326.0 | 0 | WONG, EDNA | APPARATUS AND METHOD FOR INITIATING A COMBUSTION REACTION WITH SOLID STATE SOLID FUEL | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,761,567 | ACCEPTED | Bulk high thermal conductivity feedstock and method of making thereof | The invention relates to a feedstock material for use in making heat spreaders, comprising a sheet of annealed pyrolytic graphite having a thermal conductivity of greater than 1000 watts/m-K, a size in any dimension of at least 5 cm and a thickness of at least 0.2 mm. In one embodiment, the feedstock is made by hot-pressing a stack of alternate layers of pyrolytic graphite sheets with flat graphite dies for a finished sheet of annealed pyrolytic graphite comprising a plurality of layers being parallel to each other of at least 0.075 degrees per mm of thickness. In another embodiment, the finished sheet of annealed pyrolytic graphite is made by graphitizing a stack of films comprising a high-carbon polymer. | 1. An anneal pyrolytic graphite feedstock material comprising a board of annealed pyrolytic graphite having a thermal conductivity of greater than 1000 watts/m-K, a size in any dimension of at least 5 cm, a thickness of at least 0.2 mm, wherein said board comprises a plurality of flat graphite sheets being parallel to each other and having a flatness of less than 0.075 degrees per mm of thickness. 2. The feedstock annealed pyrolytic graphite material of claim 1, having length and width dimensions of at least 5 cm respectively. 3. The feedstock annealed pyrolytic graphite material of claim 1, having a thickness of at least 0.5 mm. 4. The feedstock annealed pyrolytic graphite material of claim 1, in the form of a graphitized board of polyimide. 5. The feedstock annealed pyrolytic graphite material of claim 4, wherein said graphitized board of polyimide comprises a plurality of polyimide films having a thickness of less than 50 microns graphitized at a temperature of at least about 2800° C. 6. The feedstock annealed pyrolytic graphite material of claim 1, in the form of a hot pressed board of pyrolytic graphite. 7. The feedstock annealed pyrolytic graphite material of claim 6, wherein said board of pyrolytic graphite is hot-pressed by heating a stack of layers of plates and pyrolytic graphite sheets at sufficient temperature and pressure for a sufficient period of time to covert said pyrolytic graphite into highly oriented pyrolytic graphite. 8. The feedstock annealed pyrolytic graphite material of claim 7, wherein said board of pyrolytic graphite is hot-pressed by a plurality of graphite plates. 9. A method for manufacturing a feedstock annealed pyrolytic graphite material, the process comprising the steps: heating one or more sheets of pyrolytic graphite having a size in any dimension of at least 5 cm; heating and pressing said one or more sheets of pyrolytic graphite superimposed onto a surface of one or more plates at a temperature of at least 2900° C., thereby forming one or more sheets of annealed pyrolytic graphite comprising a plurality of graphite planes being parallel to each other within at least 0.075 degrees per mm of thickness, having a thermal conductivity of greater than 1000 watts/m-K, a size in any dimension of at least 5 cm, and a thickness of at least 0.2 mm. 9. The method of claim 9, wherein said one or more plates comprise graphite. 10. The method of claim 9, wherein said one or more plates are dies. 11. The method of claim 9, wherein one or more sheets of pyrolytic graphite are superimposed onto a surface of one or more plates. 12. A method for forming thermal pyrolytic graphite tiles for the manufacture of heat management devices, said method comprising: cleaving a board of annealed pyrolytic graphite into separate layers of pyrolytic graphite, said board having has a thermal conductivity of greater than 1000 watts/m-K, a size in any dimension of at least 5 cm, and a thickness of at least 0.2 mm; machining said layers of pyrolytic graphite into tiles of sufficient dimensions for use in heat management devices; wherein said board of annealed pyrolytic graphite comprises a plurality of graphite planes being parallel to each other to within at least 0.075 degrees per mm of thickness. 13. An article comprising the thermal pyrolytic graphite tiles manufactured by the method of claim 12. 14. An article comprising the annealed pyrolytic graphite manufactured by the method of claim 9. 15. An article comprising the pyrolytic graphite feedstock material of claim 1. | CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority on U.S. Provisional Application Ser. No. 60/504,537, filed on Sep. 19, 2003. FIELD OF THE INVENTION The present invention relates to a bulk sheet of a thermally and electrically conductive composite of thermally treated pyrolytic graphite for use in one application as a heat spreader, e.g., transferring heat away from a heat source, and method for forming a bulk sheet of thermally treated pyrolytic graphite. BACKGROUND OF THE INVENTION Electronic and/or integrated circuit (“IC”) devices, e.g., microprocessors, memory devices, and the like, are becoming smaller while heat dissipation requirements are increasing. In order to dissipate the heat generated by these devices, heat spreaders and/or heat sinks are used. Several materials and designs have been disclosed for the management and removal of heat from electronic devices. U.S. Pat. No. 5,296,310 discloses a hybrid structural device of a high thermal conductivity material sandwiched between a pair of face sheets comprising a metal or matrix-reinforced metal. The core material can be a highly ordered pyrolytic graphite, compression annealed pyrolytic graphite (CAPG), synthetic diamond, composites using these materials, or the like U.S. Pat. No. 6,215,661 discloses a heat spreader comprising an L-shaped plate of thermal pyrolytic graphite encapsulated in aluminum. U.S. Pat. No. 5,958,572 discloses a heat spreading substrate comprising an insert of thermal pyrolytic graphite (“TPG”), a diamond-like-carbon, and the like material having a plurality of vias formed within, to optimize heat flow transfer through the plurality of vias. Some forms of pyrolytic graphite in the prior art, particularly those made by chemical vapor deposition processes, suffer from non-uniform thickness, which is due to variations in crystallographic plane thickness. Adjacent crystallographic layers are substantially parallel, but variations on the crystallographic scale accumulate over macroscopic thicknesses. For example, at 1 mm, the natural layer plane surfaces are not parallel. Thermal pyrolytic graphite “tiles” having the requisite thermal conductivity properties are available in the art for the making of heat spreader. However, they have relatively small dimensions, e.g., 2 cm width and 0.1 cm thick, for making relatively small heat spreaders. U.S. Pat. No. 6,407,902 offers a solution around the small-sized pyrolytic graphite tiles with heat spreaders comprising thermal pyrolytic graphite flakes incorporated in a matrix material. The composite graphite material can be machined into spreaders of desired dimensions, obviating the use of multiple fixed small-sized graphite tiles in the art. There exists a need for a high thermal conductivity material of improved quality and size for use in devices for removing heat from electronic and IC equipment, i.e., a material suitable as a feedstock for making heat spreaders, heat inks, and the like. There is also the need for a process to make such high thermal conductivity feedstock. BRIEF SUMMARY OF THE INVENTION In one aspect of the present invention, a feedstock material for use in making heat spreaders is disclosed, the feedstock material comprising a sheet of annealed pyrolytic graphite having a thermal conductivity of greater than 1000 watts/m-K, a size in any dimension of at least 5 cm, a thickness of at least 0.2 mm, comprising a plurality of graphite planes each having a flatness of less than about 0.075 degrees per mm of thickness. The invention further relates to a method for making a feedstock material comprising a sheet of annealed pyrolytic graphite having a thermal conductivity of greater than 1000 watts/m-K, a size in any dimension of at least 5 cm, a thickness of at least 0.2 mm, comprising a plurality of graphite planes each having a flatness of less than about 0.075 degrees per mm of thickness. BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view showing a sheet of annealed pyrolytic graphite having a thickness T, a side having a length of L, and a deviation angle P. DETAILED DESCRIPTION OF THE INVENTION Applicants have developed a novel feedstock material for use in making heat management/heat spreader applications. As used herein, heat spreaders are used interchangeably with heat sinks, heat pipes, etc., referring, to a thermal management device or a heat transfer device comprising a material of high thermal conductivity for dissipating or removing heat from IC circuits, electronic devices, and the like. As known in the art, mass manufactured TPG layer parallelism worsens as the thickness of the feedstock material increases. The thickness of TPG layer can be expressed as the deviation angle P per thickness T at a distance “L” of greater than 25 mm, defined as follows and also as illustrated in FIG. 1: P = 1 T tan - 1 ( δ T L ) , wherein δT is the difference in thickness over a distance L. Also as known in the art, graphite may be characterized as laminated structures of carbon atoms having two principal axes, one is the “c” axis which is generally identified as the axis or direction perpendicular to the carbon layers; the other axis is the “a” axis or the direction parallel to the graphite layers and transverse to the c axis. In one embodiment of the invention, the novel feedstock material comprises a sheet of annealed pyrolytic graphite having a thermal conductivity of at least 1000 watts/m-K, with a size in any dimension (i.e., width, length, circumference, etc.) of at least 5 cm, and a thickness of at least 0.2 mm, with the graphite planes or layers being parallel to one another and having a flatness as expressed in deviation angle P of less than 0.075 degrees per mm thickness (in the c direction). In a second embodiment of the invention, the deviation angle P is less than 0.07 degrees per mm thickness. In a third embodiment, the deviation angle P is less than 0.05 degrees per mm thickness. Manufacture of Quality Feedstock Annealed Pyrolytic Graphite. Pyrolytic graphite generally is made by passing a carbonaceous gas at low pressure over a substrate held at a high temperature, wherein pyrolysis occurs and the pyrolytic graphite is vapor-deposited on the exposed mandrel surface. In one embodiment of the invention utilizing a chemical vapor deposition (CVD) process, a hydrocarbon gas such as methane, natural gas, acetylene, etc., is introduced into a heated furnace at a temperature of about 1300-2500° C. and a pressure of about 0.5-500 millimeters of mercury. The hydrocarbon gas would thermally decompose at the surface of a substrate of a suitable composition such as graphite (natural or synthetic), forming pyrolytic graphite in the form of a sheet or board with the use of a flat substrate. In one embodiment of the CVD process, a small amount of a volatile alloy metal source (BCl3, HfCl4, BF3, or other halides of the refractory metals), is fed into the furnace along with the hydrocarbon gas to decrease the stress levels and increase the thickness of the deposited TPG layer on the substrate. In yet another embodiment, a diluent gas that is inert to the reactant, the pyrolysis product and the substrate is incorporated in the hydrocarbon feed source. The diluent gas can be typically helium, neon, argon, krypton, xenon, radon, hydrogen, nitrogen, and the like. The introduction of the diluent gas helps in controlling the rate of carbon deposition and thus the resulting thickness of the pyrolytic graphite sheet or board. The pyrolytic graphite sheet is separated from the base substrate, and further subjected to a thermal annealing process. However, in the process of cooling to room temperature, thermal stresses are introduced into the material thus creating bow (wrinkles) condition in the pyrolytic graphite sheet of up to 1 mm per 100 mm of length of sheet. In the annealing step, the pyrolytic graphite is heated at a temperature of above 2900° C. for about 10 to 30 minutes depending oil the thickness and bulk of the product being annealed, thus forming a highly oriented pyrolytic graphite (“HOPG”) or sometimes called thermal pyrolytic graphite (“TPG”). In this process, crystallographic changes take place resulting in an improvement in layer plane orientation, a decrease in thickness normal to the layer planes (decrease in the c direction), and an increase in length and width dimensions (increase in the a direction). The improved orientation along with an increase in crystallization size results in an excellent thermal conductivity of least 1000 watts/m-K in the finished material. Applicants have found that hot-pressing the layers in the annealing process surprisingly “cures” or treats the bow condition and thus allowing TPG feedstock of desired “quality” to be made, e.g. large-sized TPG sheets of sufficient thermal conductivity and parallelism of the graphite layers for use in thermal management applications. The hot pressing may be done using processes and apparatuses known in the art, e.g., using dies, rollers, and the like. In one embodiment of the invention, the pyrolytic graphite is heat-treated within the above-mentioned temperature range and hot pressed against dies to remove uneven bumps or wrinkles generated on the carbonaceous sheets or substrates in the chemical vapor deposition process. The dies may be in the form of isotropic graphite plates having a size corresponding to a full size or partial size of the graphite sheet, e.g., covering at least 75% of the surface area of the graphite sheet. In one embodiment of this processing step, the PG sheets or boards are alternately stacked with the flat graphite plates, with a weight of a graphite block being placed on top of the stack to evenly distribute the weight onto the graphite boards. In yet another embodiment of the invention, the carbon feedstock is used in the form of a high-carbon polymer (instead of a hydrocarbon gas) for making the pyrolytic graphite sheets or boards. In one example of this process, sheets (or films) of high-carbon polymers are stacked together and hot pressed in the direction normal to the sheet at a sufficient temperature and for a sufficient amount of time for the polymeric material to carbonize and become graphitic. In one example, a stack of polyimide films (examples include Kapton® from E. I. duPont de Nemours and Upilex® from Uniglobe-Kisco, Inc.) of a size of at least 5 mm in one dimension, and a thickness of <50 microns is heated to a temperature of about 2820 to 3000° C. for complete graphitization of the films, forming an annealed pyrolytic graphite sheet having graphite planes parallel to each other, i.e., having a flatness or deviation angle of less than or equal to about 0.075 degrees per mm of thickness. In one embodiment of the invention and as taught in European Patent Application No. EP 432944 A1, the graphitized pyrolytic graphite or TPG formed is subsequently treated with an intercalating agent which % ill facilitates the exfoliation or separation of the layers of graphitized pyrolytic graphite in the c axis. After intercalation, i.e., being treated with the intercalating agent, the treated pyrolytic graphite may be washed or purged free of excess intercalating agent. Examples of intercalating agent include organic and inorganic acids such as nitric acid, sulfuric acid, perhalo acid and mixtures thereof, 7,7,8-8-tetracyanoquinomethane (TCNQ), tegracyanoethylene (TCNE), 1,2,4,5-tetracyanobenzene (TCBN), and the like; bromine and ferric chloride; nitric acid and chlorate of potash. Applications of the TPG Feedstock Material of the Invention: In one example of the invention, the finished product from the hot-pressing/annealing operation is a bulk TPG stock having a thermal conductivity of at least 1000 w/m-K, a size of at least 5 cm in one dimension, e.g., a sheet of 5 cm wide, 10 cm long, and 0.8 cm thick, comprising multiple layers (similar to shale or mica) of graphite with little or no bow (uneven-ness in the surface of the layers) with the layers being parallel to one another, defined as having a flatness or deviation angle of less than about 0.075 degrees per mm of thickness. In the example above, the graphite layers or the bulk TPG stock can be subsequently cleaved into layers of desired thickness, e.g., 8 layers of 0.1 cm thick and machined into individual tiles for heat spreaders application. In one operation, the 5 cm by 10 cm by 0.8 cm bulk TPG stock of the invention can be made into 64 square tiles of 2.4 cm by 0.1 cm thick. In a comparable example, a prior art feedstock TPG sheet is used in making TPG tiles of the same dimensions. The bulk stock is a typical commercially available sheet of 0.1 mm of curvature in the layer planes over a thickness of 0.8 cm. The sheet is also cleaved as in the above example to make finished tiles of 0.1 cm thick. However, in order to make a flat tile, each cleaved piece must have 0.1 mm excess material per side to allow for machining, i.e., each cleaved piece must be 1.2 mm thick hence only 6 tie layers of a flat 0.1 cm thick can be made from the TPG stock of the prior art. The process results in a minimum of 25% material waste (6 parts as opposed to 8 parts using the TPG feedstock of the present invention) as well as loss time required in the machining process to obtain flat tiles of 0.1 cm thick. EXAMPLES Examples are provided herein to illustrate the invention but are not intended to limit the scope of the invention. In the examples, TPG sheets prepared by a CVD process is thermally annealed at a temperature of about 2900° C.-3200° C. for about 10 minutes to up to 2 hours, wherein the sheets are hot pressed by isotropic graphite plates while being thermally annealed for the resulting bulk TPG sheet of the following Examples. Example 1 In this example, thickness and deviation of the thickness is measured at about every 76 mm apart along the length of the 356 mm long TPG slab. The deviation angle is calculated per formula. The P value found to be less than 0.075 degrees per mm thickness, with the results are as follows: Distance mm L 25.4 101.6 177.8 254 356 Thickness variation dT 0.05 0.127 0.228 0.279 0.355 mm Thickness mm T 15.21 15.26 15.26 15.29 15.39 Degrees/mm P 0.007 0.005 0.005 0.004 0.004 thickness Example 2 In the second example, thickness and deviation of the thickness is measured at about every 76 mm apart along the length of a 380 mm long TPG slab. The deviation angle is calculated per formula. The P value is also found to be less than 0.075 degrees per mm thickness: Distance mm L 25.4 101.6 177.6 254 356 Thickness variation dT 0.152 0.127 0.279 0.533 1.066 mm Thickness mm T 10.71 10.74 10.76 10.81 11.02 Degrees/mm P 0.032 0.007 0.008 0.011 0.016 thickness Example 3 In the third example, thickness and deviation of the thickness is measured at about every 76 mm apart along the length of a 260 mm long TPG slab. The deviation angle is calculated per formula. Again, the P value is found to be less than 0.075 degrees per mm thickness: Distance mm L 25.4 101.6 177.6 254 Thickness variation mm dT 0.177 0.12 0.076 0.279 Thickness mm T 13.46 13.58 13.66 13.7 Degrees/mm thickness P 0.007 0.003 0.001 0.005 While the invention has been described with reference to a preferred embodiment, those skilled in the art will understand that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. It is intended that the invention not be limited to the particular embodiment disclosed as the best mode for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. All citations referred herein are expressly incorporated herein by reference. | <SOH> BACKGROUND OF THE INVENTION <EOH>Electronic and/or integrated circuit (“IC”) devices, e.g., microprocessors, memory devices, and the like, are becoming smaller while heat dissipation requirements are increasing. In order to dissipate the heat generated by these devices, heat spreaders and/or heat sinks are used. Several materials and designs have been disclosed for the management and removal of heat from electronic devices. U.S. Pat. No. 5,296,310 discloses a hybrid structural device of a high thermal conductivity material sandwiched between a pair of face sheets comprising a metal or matrix-reinforced metal. The core material can be a highly ordered pyrolytic graphite, compression annealed pyrolytic graphite (CAPG), synthetic diamond, composites using these materials, or the like U.S. Pat. No. 6,215,661 discloses a heat spreader comprising an L-shaped plate of thermal pyrolytic graphite encapsulated in aluminum. U.S. Pat. No. 5,958,572 discloses a heat spreading substrate comprising an insert of thermal pyrolytic graphite (“TPG”), a diamond-like-carbon, and the like material having a plurality of vias formed within, to optimize heat flow transfer through the plurality of vias. Some forms of pyrolytic graphite in the prior art, particularly those made by chemical vapor deposition processes, suffer from non-uniform thickness, which is due to variations in crystallographic plane thickness. Adjacent crystallographic layers are substantially parallel, but variations on the crystallographic scale accumulate over macroscopic thicknesses. For example, at 1 mm, the natural layer plane surfaces are not parallel. Thermal pyrolytic graphite “tiles” having the requisite thermal conductivity properties are available in the art for the making of heat spreader. However, they have relatively small dimensions, e.g., 2 cm width and 0.1 cm thick, for making relatively small heat spreaders. U.S. Pat. No. 6,407,902 offers a solution around the small-sized pyrolytic graphite tiles with heat spreaders comprising thermal pyrolytic graphite flakes incorporated in a matrix material. The composite graphite material can be machined into spreaders of desired dimensions, obviating the use of multiple fixed small-sized graphite tiles in the art. There exists a need for a high thermal conductivity material of improved quality and size for use in devices for removing heat from electronic and IC equipment, i.e., a material suitable as a feedstock for making heat spreaders, heat inks, and the like. There is also the need for a process to make such high thermal conductivity feedstock. | <SOH> BRIEF SUMMARY OF THE INVENTION <EOH>In one aspect of the present invention, a feedstock material for use in making heat spreaders is disclosed, the feedstock material comprising a sheet of annealed pyrolytic graphite having a thermal conductivity of greater than 1000 watts/m-K, a size in any dimension of at least 5 cm, a thickness of at least 0.2 mm, comprising a plurality of graphite planes each having a flatness of less than about 0.075 degrees per mm of thickness. The invention further relates to a method for making a feedstock material comprising a sheet of annealed pyrolytic graphite having a thermal conductivity of greater than 1000 watts/m-K, a size in any dimension of at least 5 cm, a thickness of at least 0.2 mm, comprising a plurality of graphite planes each having a flatness of less than about 0.075 degrees per mm of thickness. | 20040121 | 20070522 | 20050324 | 67134.0 | 1 | MILLER, DANIEL H | BULK HIGH THERMAL CONDUCTIVITY FEEDSTOCK AND METHOD OF MAKING THEREOF | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,761,577 | ACCEPTED | Call waiting calling party defined content | Embodiments of the method and system provide for providing a call waiting method for use in a telecommunications network in which a first caller is engaged in a current call with a second caller, and for processing an incoming call from a third caller to the first caller. The method may have the steps of: providing identification of a plurality of callers in a predefined caller group; detecting an incoming call from a third caller to a first caller, the first caller presently being engaged in a current call with a second caller; checking if the third caller is a member of the predefined caller group; if the third caller is a member of the predefined caller group, signaling the third caller to leave a message to be sent to the first caller with a call waiting indication, recording a message from the third caller, and providing to the first caller a call waiting indication along with the recorder message from the third caller; and, if the third caller is not a member of the predefined caller group, providing to the first caller only a call waiting indication. The system implements the method. | 1. A call waiting method for use in a telecommunications network in which a first caller is engaged in a current call with a second caller, and for processing an incoming call from a third caller to the first caller, the method comprising the steps of: providing identification of a plurality of callers in a predefined caller group; detecting an incoming call from a third caller to a first caller, the first caller presently being engaged in a current call with a second caller; checking if the third caller is a member of the predefined caller group; if the third caller is a member of the predefined caller group: signaling the third caller to leave a message to be sent to the first caller with a call waiting indication; recording a message from the third caller; providing to the first caller a call waiting indication along with the recorder message from the third caller; and if the third caller is not a member of the predefined caller group: providing to the first caller only a call waiting indication. 2. The method according to claim 1, wherein the call waiting indication is at least one of a predetermined tone, an image, and a caller identification. 3. The method according to claim 1, wherein the step of providing identification of a plurality of callers in a predefined caller group comprises the steps of: selecting, by the first caller, callers to be added to the caller group; communicating identification of the selected callers the telecommunication network; and storing the identifications of the selected callers in a storage in the telecommunication network. 4. The method according to claim 3, wherein the step of checking if the third caller is a member of the predefined caller group comprises the steps of: comparing an identity of the third caller to the stored identifications of the selected callers in the storage in the telecommunication network to determine if the third caller is a member of the caller group; and providing a message signal indicative of a result of the comparison. 5. The method according to claim 1, wherein the identifications of the selected callers are stored at least in a subscriber database in the telecommunications network. 6. The method according to claim 1, wherein the recorded message is temporarily stored in a message database in the telecommunications network. 7. The method according to claim 1, wherein the recorded message is replayable by the first caller. 8. The method according to claim 1, wherein the recorded message is saveable by the first caller. 9. The method according to claim 1, wherein the method further comprises converting the recorded message to text for imaging on a display of a terminal of the first caller. 10. A call waiting method for use in a telecommunications network in which a first caller is engaged in a current call with a second caller, and for processing an incoming call from a third caller to the first caller, the method comprising the steps of: selecting, by the first caller, callers to be added to a caller group; communicating identification of the selected callers to the telecommunication network; storing the identifications of the selected callers in a subscriber database in the telecommunication network; detecting an incoming call from a third caller to a first caller, the first caller presently being engaged in a current call with a second caller; comparing an identity of the third caller to the stored identifications of the selected callers in the subscriber database in the telecommunication network to determine if the third caller is a member of the caller group; providing a message signal indicative of a result of the comparison; if the message signal indicates that the third caller is a member of the predefined caller group: signaling the third caller to leave a message to be sent to the first caller with a call waiting indication; recording a message from the third caller; providing to the first caller a call waiting indication along with the recorder message from the third caller; and if the signal indicates that the third caller is not a member of the predefined caller group: providing to the first caller only a call waiting indication. 11. The method according to claim 10, wherein the call waiting indication is at least one of a predetermined tone, an image, and a caller identification. 12. The method according to claim 1, wherein the recorded message is temporarily stored in a message database in the telecommunications network. 13. The method according to claim 1, wherein the recorded message is replayable by the first caller. 14. The method according to claim 1, wherein the recorded message is saveable by the first caller. 15. The method according to claim 1, wherein the method further comprises converting the recorded message to text for imaging on a display of a terminal of the first caller. 16. A call waiting system for use in a telecommunications network in which a first caller is engaged in a current call with a second caller, and wherein an incoming call from a third caller is received for the first caller, the system comprises: a caller group having at least one caller selected by the first caller; a subscriber database in the telecommunication network in which is stored identifications of the selected callers in the caller group; a recognition module operatively connected to the subscriber database, wherein upon detecting an incoming call from a third caller to a first caller, the first caller presently being engaged in a current call with a second caller, the recognition module comparing an identity of the third caller to the stored identifications of the selected callers in the subscriber database in the telecommunication network to determine if the third caller is a member of the caller group, and the recognition module having an output for outputting a message signal indicative of a result of the comparison; a message interface module operatively connected to the recognition module, the interface module having an input for receiving the signal, the interface module having an output for providing a signaling to the third caller that requests the third caller to leave a message when the message signal indicates that the third caller is a member of the predefined caller group; a recording module operatively connected to the message interface module, the recording module recording the message from the third caller; and a message database operatively connected to the message interface module, the recorded message being stored in the message database; wherein the recorded message from the third caller is provided to the first caller after a call waiting indication is provided to the first caller. 17. The system according to claim 16, wherein the call waiting indication is at least one of a predetermined tone, an image, and a caller identification. 18. The system according to claim 16, wherein the recorded message is temporarily stored in the message database in the telecommunications network. 19. The system according to claim 16, wherein the recorded message is replayable by the first caller. 20. The system according to claim 16, wherein the recorded message is saveable by the first caller. | TECHNICAL FIELD The present invention relates to telephony in general, and, more particularly, to a method and system that allows selected calling parties to record a brief voice message that will be used in addition to the normal call waiting tone. BACKGROUND OF THE INVENTION Telephone companies have provided, for a number of years, a call waiting service to which their customers may subscribe. If a customer subscribes to the call waiting service, then when the customer is on the telephone talking with a first party and a second party telephones the customer during the course of the conversation with the first party, the customer will hear a beep in the earpiece of the telephone to alert them to the fact that another call is waiting. The customer can then transmit a flash hook to the telephone company's central office, placing the conversation with the first party on hold and connecting the customer with the second party, allowing the customer to then enter into a conversation with the second party. However, the customer has no way of knowing who the second party is when they hear the beep in the earpiece and they have no idea whether or not the call from the second party is sufficiently urgent to warrant interrupting the conversation with the first party. Newer methods for call delivery to a customer are, for example, the Integrated Services Digital Network (ISDN) that may have digital signaling channels for notification of an attempt, on the part of the network, to deliver a call to a customer. With ISDN, a customer can be notified of the attempt to deliver the call even though the customer may be engaged in a telephone call or connection with another party. Such notification can be made at the customer's telephone station or at a separate terminal. Additionally, the customer can also receive information related to the second call, such as Calling Line IDentification (CLID). This information may be displayed on the customer's station. Given this information, which is the telephone number of the calling party, the customer may elect to put the call in progress on hold and to connect with the new call. However, ISDN does not allow the calling party to identify the urgency of their call or to provide the user with a notification initiated by and defined by the calling party. Furthermore, the customer has no control over what parties are allowed to utilize the customer's call waiting feature. Thus, it is a drawback of the prior art that there does not exist a database of preferred calling numbers that is provisioned by the subscriber. It is a further drawback of the prior art that the calling party cannot record a short message that may be used in addition to the normal call waiting tone. SUMMARY The following summary of embodiments of the invention is provided to facilitate an understanding of some of the innovative features unique to the present invention and is not intended to be a full description. A full appreciation of the various aspects of the invention can be gained by taking the entire specification, claims, drawings, and abstract as a whole. In general terms, an embodiment of the present method is a call waiting method for use in a telecommunications network in which a first caller is engaged in a current call with a second caller, and for processing an incoming call from a third caller to the first caller. The method may have the steps of: providing identification of a plurality of callers in a predefined caller group; detecting an incoming call from a third caller to a first caller, the first caller presently being engaged in a current call with a second caller; checking if the third caller is a member of the predefined caller group; if the third caller is a member of the predefined caller group, signaling the third caller to leave a message to be sent to the first caller with a call waiting indication, recording a message from the third caller, and providing to the first caller a call waiting indication along with the recorder message from the third caller; and, if the third caller is not a member of the predefined caller group, providing to the first caller only a call waiting indication. Also, in general terms, an embodiment of the present system is a call waiting system for use in a telecommunications network in which a first caller is engaged in a current call with a second caller, and wherein an incoming call from a third caller is received for the first caller. The system may have the following components: a caller group having at least one caller selected by the first caller; a subscriber database in the telecommunication network in which is stored identifications of the selected callers in the caller group; a recognition module operatively connected to the subscriber database, wherein upon detecting an incoming call from a third caller to a first caller, the first caller presently being engaged in a current call with a second caller, the recognition module comparing an identity of the third caller to the stored identifications of the selected callers in the subscriber database in the telecommunication network to determine if the third caller is a member of the caller group, and the recognition module having an output for outputting a message signal indicative of a result of the comparison; a message interface module operatively connected to the recognition module, the interface module having an input for receiving the signal, the interface module having an output for providing a signaling to the third caller that requests the third caller to leave a message when the message signal indicates that the third caller is a member of the predefined caller group; a recording module operatively connected to the message interface module, the recording module recording the message from the third caller; and a message database operatively connected to the message interface module, the recorded message being stored in the message database; wherein the recorded message from the third caller is provided to the first caller after a call waiting indication is provided to the first caller. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying figures, in which like reference numerals refer to identical or functionally-similar elements throughout the separate views and which are incorporated in and form part of the specification, further illustrate the present invention and, together with the detailed description of the invention, serve to explain the principles of the present invention. FIG. 1 depicts a block diagram illustrative of a mobile switching center, base station and mobile terminal for use with the present method and system. FIG. 2 illustrates a more detailed block diagram illustrative of a mobile switching center, base station, and mobile terminal according to one embodiment of the present method and system. FIG. 3 illustrates a very general flow chart of logical operational steps that may be followed in accordance with one embodiment of the present method and system. FIG. 4 illustrates another flow chart of logical operational steps that may be followed in accordance with one embodiment of the present method and system. DETAILED DESCRIPTION The particular values and configurations discussed in these non-limiting examples can be varied and are cited merely to illustrate an embodiment of the present invention and are not intended to limit the scope of the invention. When a subscriber is active on a call and another call is inbound the traditional call waiting features generates a call waiting tone along with the callers identification. Embodiments of the present method and system provide the capability for selected calling parties to record a short announcement message that will be used instead of the call waiting tone. When the call is placed the calling parties number may be checked against the preferred list. If it is on the list and the called party is currently busy on a call, the calling party will be prompted, via a specialized tone or announcement, to record a short voice message that will be used in addition to the call waiting tone. One advantage of the present method and system occurs when wireless subscribers use their phones while in an automobile or in transit. The convenience of having a short audio message relayed to them instead of a tone eliminates the need to pull the phone away from their face and look at the caller ID. This removes a distraction when the subscriber is driving a vehicle, for example. It also may eliminate the need to retrieve a voice mail message if the short announcement contains enough information that a message is not required. A further benefit to the subscriber is that the subscriber is able to judge if the incoming call is important enough to place the current call on hold. Also, obtaining information by the announcement will be less of an interruption to the current call than current call waiting methods. The present method and system may be used with wireless, as well as, wired telecommunication networks. Referring to FIG. 1, one example of a telecommunication network 100 is depicted. At least one mobile terminal 112 of a plurality of mobile terminals may be operatively connected to the telecommunication network 100. Although the present system and method may be used with any type of network (wired and wireless, for example), the subscriber may typically be a mobile subscriber who uses a mobile terminal (also referred to as mobile phone, a cell phone, mobile handset, or car phone). As depicted in the FIG. 1 embodiment, the network (or telecommunication network) 100 may have a mobile switching center (MSC) 102. The network 100 may be, or may be part of, one or more of a telephone network, a local area network (“LAN”), the Internet, and a wireless network. In the depicted embodiment, a public switched telephone network (PSTN) 104 is connected to the MSC 102. The PSTN 104 routes calls to and from mobile users through the MSC 102. The PSTN 104 also routes calls from and to wireline stations 106. The MSC 102 may also be connected to one or more base stations (BS) 110. Each of the base stations 110 communicates with mobile terminal(s) 112 in its service area. The PSTN 104 generally may be implemented as the worldwide voice telephone network accessible to all those with telephones and access privileges (e.g., AT&T long distance network). Each of the mobile terminals 112 may have a home location register (HLR) 114 where data about each of the mobile terminals 112 resides. Some of the mobile terminals 112 may be remotely located from their home location, and in that case, a visiting location register (VLR) 116 is set up locally for each mobile terminal 112 that is visiting in its service area. HLR 114 can be implemented as a permanent SS7 database utilized in cellular networks, such as, but not limited to, for example, AMPS (Advanced Mobile Phone System), GSM (Global System for Mobile Communications), and PCS. HLR 114 may be utilized generally to identify/verify a subscriber, and also contains subscriber data related to features and services. HLR 114 is generally utilized not only when a call is being made within a coverage area supported by a cellular provider of record, but also to verify the legitimacy and to support subscriber features when a subscriber is away from his or her home area. VLR 116, on the other hand, may be implemented as a local database maintained by the cellular provider whose territory is being roamed. Mobile terminal 112 may be implemented as a cellular device, personal communication device, short message service device or wireless communications device (e.g., a wireless personal digital assistant). The MCS 102 may have, or be operatively connected to, components of a system for providing a call waiting feature. Such components in some embodiments may include: call waiting module 101, call controller 103 and storage 107 (such as a subscriber database) in the MCS 102. Referring to FIG. 2, a network (or telecommunication network) 200 is shown for at least one mobile terminal 212 of a plurality of mobile terminals operatively connected to the telecommunication network 200, which has a mobile switching center 202. FIG. 2 is a block diagram that is illustrative of a mobile switching center 202 operatively connected to PSTN 204, base station 210, and mobile terminal 212 according to one embodiment of the present method and system. The PSTN 204 routes calls to and from mobile terminal(s) 212 through the MSC 202, and also routes calls from and to wireline stations 206. The MSC 202 is connected to one or more base stations 210. The base station(s) 210 communicates through the air to mobile terminals 212, which, for example, may be of a cellular telephone type or of the wider bandwidth personal communication device type. Mobile terminals 212, for example, may be wireless handsets or automobile mounted stations the same as those shown in FIG. 1. The MSC 202 has operatively connected thereto a VLR 216 and a HLR 214 that interface with the mobile terminal 212 as explained above. In general terms the present system may have the following components: a caller group having at least one caller selected by the first caller; a subscriber database 211 in the telecommunication network 200 in which is stored identifications of the selected callers in the caller group; a recognition module 232 operatively connected to the subscriber database 211, wherein upon detecting an incoming call from a third caller to a first caller, the first caller presently being engaged in a current call with a second caller, the recognition module 232 comparing an identity of the third caller to the stored identifications of the selected callers in the subscriber database 211 in the telecommunication network 200 to determine if the third caller is a member of the caller group, and the recognition module 232 having an output for outputting a message signal indicative of a result of the comparison; a message interface module 230 operatively connected to the recognition module 232, the interface module 230 having an input for receiving the signal, the interface module 230 having an output for providing a signaling to the third caller that requests the third caller to leave a message when the message signal indicates that the third caller is a member of the predefined caller group; a recording module 234 operatively connected to the message interface module 230, the recording module 234 recording the message from the third caller; and a message database 209 operatively connected to the message interface module 230, the recorded message being stored in the message database 209; wherein the recorded message from the third caller is provided to the first caller after a call waiting indication is provided to the first caller. The subscriber database 211 and message database 209 may be separate storage elements, or may be portions of a common storage 207. The call waiting indication may be at least one of a predetermined tone (or combination of tones), an image, and a caller identification (such as, the phone number of the third caller. In an alternative embodiment the recorded message may be used instead of the predetermined tone. The recorded message may be temporarily stored in the message database 207 in the telecommunications network 200. Also, the recorded message may be replayed by the first caller, and/or saved by the first caller. The messages may be exchanged between the telecommunication network 200 and the mobile terminal 212 via at least one of email, SMS, and data for display on the display 217 of the mobile terminal 212. Embodiments of the messages and the format for sending the messages may take many different forms in various embodiments of the present method and system. FIG. 3 is a general block diagram depicting an embodiment of the present method. In very general terms, the method may have the steps of: providing identification of a plurality of callers in a predefined caller group (step 301); detecting an incoming call from a third caller to a first caller, the first caller presently being engaged in a current call with a second caller (step 302); checking if the third caller is a member of the predefined caller group (step 303); if the third caller is a member of the predefined caller group, signaling the third caller to leave a message to be sent to the first caller with a call waiting indication (step 304), recording a message from the third caller (step 305), and providing to the first caller a call waiting indication along with the recorder message from the third caller (step 306); and, if the third caller is not a member of the predefined caller group, providing to the first caller only a call waiting indication (step 307). FIG. 4 is a block diagram depicting another embodiment of the present method. This embodiment of the method may have the steps of: selecting, by the first caller, callers to be added to a caller group (401); communicating identification of the selected callers to the telecommunication network (402); storing the identifications of the selected callers in a subscriber database in the telecommunication network (403); detecting an incoming call from a third caller to a first caller, the first caller presently being engaged in a current call with a second caller (404); comparing an identity of the third caller to the stored identifications of the selected callers in the subscriber database in the telecommunication network to determine if the third caller is a member of the caller group; providing a message signal indicative of a result of the comparison (405); if the message signal indicates that the third caller is a member of the predefined caller group, signaling the third caller to leave a message to be sent to the first caller with a call waiting indication (406), recording a message from the third caller (407), and providing to the first caller a call waiting indication along with the recorder message from the third caller (408); and, if the signal indicates that the third caller is not a member of the predefined caller group, providing to the first caller only a call waiting indication (409). FIGS. 5-7 depict one example of the operation of an embodiment of the present method and system. As depicted in FIG. 5, party A has a mobile terminal 504, party B has a mobile terminal 506, and party C has a mobile terminal 508. FIG. 5 shows the MSC 500 having a subscriber database 502. FIG. 5 also shows an established call between party A and party B. Party A has provisioned a list of preferred calling numbers that are allowed to activate the Call Waiting Calling Party Defined Content feature prior to the incoming call. When party C calls party A, the MSC 500 checks to see if the called party has this feature and checks the database 502 in the MSC 500 for the preferred numbers for party A. If party C is on the preferred list, and party A is busy with a call, the feature is activated. As depicted in FIG. 6, party A has a mobile terminal 604, party B has a mobile terminal 606, and party C has a mobile terminal 608. FIG. 6 shows the MSC 600 having a subscriber database 602 and a short voice message recording 610. FIG. 6 also shows how the MSC 600 captures the calling party's (party C) call waiting content. The MSC 600 signals to party C to leave a short message that will be used in the Call Waiting alert. Party C leaves a short message that is captured to a short voice message recording system 710. The duration of the message may be any length and may be provisioned by the service provider of the service. As depicted in FIG. 7, party A has a mobile terminal 704, party B has a mobile terminal 706, and party C has a mobile terminal 708. FIG. 7 shows the MSC 700 having a subscriber database 702 and a short voice message recording 710. The MSC 700 delivers the calling party defined content. The MSC 700 first opens the voice path between Party B and Party A. The MSC 700 then inserts the short voice message content following the call waiting tone. Party A hears the short message while party B is played comfort noise/ music for that duration. Party A can perform any action that normally would be allowed after a call waiting tone is delivered. Party A can put party B on hold and connect with party C, or party A can ignore the call. Alternatively, if Party A wants to hear the short message again, this can be accomplished by Party A entering a function code while still connected with party B. Alternatively, if Party A wants to retrieve the message after the party A—party B call completes, it can enter a function code and the announcement will be stored in Party A's voice mail service. Therefore, the improved present method and system overcomes the drawbacks of the prior art and provides a database of preferred calling numbers that is provisioned by the subscriber. The improved present method and system further provides that the calling party can record a short message that may be used in addition to or instead of the normal call waiting tone. Such is not found in the prior art. The present system and method may be used with non-mobile phones, as well as, mobile phones. Also, different types of data storage devices may be used with the present method and system. For example, a data storage device may be one or more of a magnetic, electrical, optical, biological, and atomic data storage medium. The method and system of the present invention may be implemented in hardware, software, or combinations of hardware and software. In a software embodiment, portions of the present invention may be computer program products embedded in computer readable medium. Portions of the system may employ and/or comprise a set and/or series of computer instructions written in or implemented with any of a number of programming languages, as will be appreciated by those skilled in the art. The embodiments and examples set forth herein are presented to best explain the present invention and its practical application and to thereby enable those skilled in the art to make and utilize the invention. Those skilled in the art, however, will recognize that the foregoing description and examples have been presented for the purpose of illustration and example only. Other variations and modifications of the present invention will be apparent to those of skill in the art, and it is the intent of the appended claims that such variations and modifications be covered. The description as set forth is not intended to be exhaustive or to limit the scope of the invention. Many modifications and variations are possible in light of the above teaching without departing from the scope of the following claims. It is contemplated that the use of the present invention can involve components having different characteristics. It is intended that the scope of the present invention be defined by the claims appended hereto, giving full cognizance to equivalents in all respects. | <SOH> BACKGROUND OF THE INVENTION <EOH>Telephone companies have provided, for a number of years, a call waiting service to which their customers may subscribe. If a customer subscribes to the call waiting service, then when the customer is on the telephone talking with a first party and a second party telephones the customer during the course of the conversation with the first party, the customer will hear a beep in the earpiece of the telephone to alert them to the fact that another call is waiting. The customer can then transmit a flash hook to the telephone company's central office, placing the conversation with the first party on hold and connecting the customer with the second party, allowing the customer to then enter into a conversation with the second party. However, the customer has no way of knowing who the second party is when they hear the beep in the earpiece and they have no idea whether or not the call from the second party is sufficiently urgent to warrant interrupting the conversation with the first party. Newer methods for call delivery to a customer are, for example, the Integrated Services Digital Network (ISDN) that may have digital signaling channels for notification of an attempt, on the part of the network, to deliver a call to a customer. With ISDN, a customer can be notified of the attempt to deliver the call even though the customer may be engaged in a telephone call or connection with another party. Such notification can be made at the customer's telephone station or at a separate terminal. Additionally, the customer can also receive information related to the second call, such as Calling Line IDentification (CLID). This information may be displayed on the customer's station. Given this information, which is the telephone number of the calling party, the customer may elect to put the call in progress on hold and to connect with the new call. However, ISDN does not allow the calling party to identify the urgency of their call or to provide the user with a notification initiated by and defined by the calling party. Furthermore, the customer has no control over what parties are allowed to utilize the customer's call waiting feature. Thus, it is a drawback of the prior art that there does not exist a database of preferred calling numbers that is provisioned by the subscriber. It is a further drawback of the prior art that the calling party cannot record a short message that may be used in addition to the normal call waiting tone. | <SOH> SUMMARY <EOH>The following summary of embodiments of the invention is provided to facilitate an understanding of some of the innovative features unique to the present invention and is not intended to be a full description. A full appreciation of the various aspects of the invention can be gained by taking the entire specification, claims, drawings, and abstract as a whole. In general terms, an embodiment of the present method is a call waiting method for use in a telecommunications network in which a first caller is engaged in a current call with a second caller, and for processing an incoming call from a third caller to the first caller. The method may have the steps of: providing identification of a plurality of callers in a predefined caller group; detecting an incoming call from a third caller to a first caller, the first caller presently being engaged in a current call with a second caller; checking if the third caller is a member of the predefined caller group; if the third caller is a member of the predefined caller group, signaling the third caller to leave a message to be sent to the first caller with a call waiting indication, recording a message from the third caller, and providing to the first caller a call waiting indication along with the recorder message from the third caller; and, if the third caller is not a member of the predefined caller group, providing to the first caller only a call waiting indication. Also, in general terms, an embodiment of the present system is a call waiting system for use in a telecommunications network in which a first caller is engaged in a current call with a second caller, and wherein an incoming call from a third caller is received for the first caller. The system may have the following components: a caller group having at least one caller selected by the first caller; a subscriber database in the telecommunication network in which is stored identifications of the selected callers in the caller group; a recognition module operatively connected to the subscriber database, wherein upon detecting an incoming call from a third caller to a first caller, the first caller presently being engaged in a current call with a second caller, the recognition module comparing an identity of the third caller to the stored identifications of the selected callers in the subscriber database in the telecommunication network to determine if the third caller is a member of the caller group, and the recognition module having an output for outputting a message signal indicative of a result of the comparison; a message interface module operatively connected to the recognition module, the interface module having an input for receiving the signal, the interface module having an output for providing a signaling to the third caller that requests the third caller to leave a message when the message signal indicates that the third caller is a member of the predefined caller group; a recording module operatively connected to the message interface module, the recording module recording the message from the third caller; and a message database operatively connected to the message interface module, the recorded message being stored in the message database; wherein the recorded message from the third caller is provided to the first caller after a call waiting indication is provided to the first caller. | 20040121 | 20060725 | 20050721 | 96041.0 | 0 | BUI, BING Q | CALL WAITING CALLING PARTY DEFINED CONTENT | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,761,578 | ACCEPTED | Method and system for automating creation of multiple stylesheet formats using an integrated visual design environment | A unified visual design environment in a data processing system to enable automatic generation of a plurality of stylesheets for different output formats. The invention enables support for visual editing and generation of extensible Stylesheet Language (XSL) code, such as XSL code that enables XML content to be rendered into an HTML file, XSL:FO code that enables XML content to be rendered into a PDF file, and the like. With a single stylesheet design, developers can preview an output of a stylesheet transformation in one of several different formats, e.g., HTML, PDF, or others. | 1. In a data processing system having a windows-based graphical user interface (GUI), the improvement comprising: an integrated visual design environment having a first display panel in which a structured data source is displayed, and a second display panel for displaying a document being designed from the structured data source; code responsive to selection and positioning in the second display panel of given design elements or attributes from the structured data source for generating a meta stylesheet; and code for automatically generating from the meta stylesheet two or more stylesheets from within the integrated visual design environment, wherein each of the stylesheets is useful for generating the document being designed in a given output format. 2. In the data processing system as described in claim 1 further including: code responsive to a given selection for selectively displaying a preview of a given one of the two or more stylesheets. 3. In the data processing system as described in claim 1 wherein the structured data source is an XML document. 4. In the data processing system as described in claim 1 wherein the structured data source is a Document Type Definition (DTD). 5. In the data processing system as described in claim 1 wherein the structured data source is an XML Schema. 6. In the data processing system as described in claim 1 wherein the structured data source is a relational database. 7. In the data processing system as described in claim 1 wherein the structured data source is an EDI document. 8. In the data processing system as described in claim 3 wherein the two or more stylesheets include an XSLT stylesheet for transforming the XML document into HTML. 9. In the data processing system as described in claim 3 wherein the two or more stylesheets include an XSLT stylesheet to faciliate transformation of the XML document into PDF via XSL:FO. 10. In the data processing system as described in claim 3 wherein the two or more stylesheets include an XSLT stylesheet for transforming the XML document into WML. 11. In the data processing system as described in claim 1 wherein the integrated visual design environment also includes a display panel for manipulating schema elements and attributes. 12. In the data processing system as described in claim 11 wherein the display panel for manipulating schema elements and attributes includes a text style display window and an associated control mechanism to provide text formatting. 13. In the data processing system as described in claim 11 wherein the display panel for manipulating schema elements and attributes includes a block system display window and an associated control mechanism to provide block formatting. 14. In the data processing system as described in claim 1 further including: code responsive to a given selection for selectively displaying a preview of an output document rendered as a result of applying a given one of the two or more stylesheets. 15. A data processing system having a windows-based graphical user interface (GUI), comprising: a display environment having a first display panel in which a structured data source is displayed, and a second display panel for displaying a document being designed from the structured data source, wherein the data source is selected from a set of data sources including: an XML document, an XML schema, a DTD, an EDI document, a relational database, and a Web service; code responsive to selection and positioning in the second display panel of given design elements or attributes from the structured data source for generating given program code; and code for automatically generating from the given program code two or more program code instances from within the integrated visual design environment, wherein each of the program code instances is useful for generating the document being designed in a given output format. 16. The data processing system as described in claim 15 wherein a given program code instance is an XSLT stylesheet. 17. The data processing system as described in claim 15 wherein a given program code instance is code written in a programming language selected from a set of available language templates. 18. The data processing system as described in claim 15 further including: code responsive to a given selection for selectively displaying a preview of a given one of the program code instances. 19. The data processing system as described in claim 15 further including: code responsive to a given selection for selectively displaying a preview of an output document rendered as a result of applying a given one of the program code instances. 20. A display method operative in a data processing system having a windows-based graphical user interface (GUI), comprising: displaying, in juxtaposition, a structured data source and a document being designed from the structured data source, wherein the data source is selected from a set of data sources including: an XML document, an XML schema, a DTD, an EDI document, a relational database, and a Web service; responsive to selection and positioning in the document being designed of given design elements or attributes from the structured data source, generating given program code; automatically generating from the given program code two or more program code instances, wherein each of the program code instances is useful for generating the document being designed in a given output format; and selectively displaying a preview of an output document rendered as a result of applying a given one of the program code instances. | BACKGROUND OF THE INVENTION 1. Technical Field The present invention relates generally to data integration technologies and, in particular, to techniques for authoring stylesheets in an XML application development environment. 2. Description of the Related Art Organizations today are realizing substantial business efficiencies in the development of data intense, connected, software applications that provide seamless access to database systems within large corporations, as well as externally linking business partners and customers alike. Such distributed and integrated data systems are a necessary requirement for realizing and benefiting from automated business processes, yet this goal has proven to be elusive in real world deployments for a number of reasons including the myriad of different database systems and programming languages involved in integrating today's enterprise back-end systems. Extensible Markup Language (XML) technologies are ideally suited to solve advanced data integration challenges, because they are both platform and programming language neutral, inherently transformable, easily stored and searched, and already in a format that is easily transmittable to remote processes via XML-based Web services technologies. XML is a subset of SGML (the Structured Generalized Markup Language) that has been defined by the World Wide Web Consortium (W3C) and has a goal to enable generic SGML to be served, received and processed on the Web. XML is a clearly defined way to structure, describe, and interchange data. XML technologies offer the most flexible framework for solving advanced data integration applications. They do not, however, encompass the entire solution, in that a particular solution must still be implemented. Thus, XML technologies are not a standalone replacement technology, but rather a complementary enabling technology, which when bound to a particular programming language and database provide an elegant solution to a different problem. There are a number of ancillary technologies associated with XML. The extensible Stylesheet Language (XSL) consists of, among other things, the extensible Stylesheet Language Transformation (XSLT), a standardized language for transforming XML documents to simple output forms such as HTML or WML, and the extensible Stylesheet Language Formatting Objects (XSL:FO), an XML-based language for expressing advanced document layouts, employed by many popular formats including PDF and PostScript files. XSL decouples the contents of a document from its style (i.e., the document's layout and formatting). This allows a designer to either change the document's style without affecting the content, or to change the content while preserving the style. The transformation process from one data format to another involves processing an XML document and an XSL stylesheet in an XSL processor, which results in the generation of a new output document. An example of altering a document's style while preserving the content is multi-channel publishing. Using XSL, a single source of XML content can be published into a wide variety of customized output media, such as HTML, WML, PostScript, PDF, or any other information format, through the application of a stylesheet. An example of changing a document's content while preserving the style is internationalization and localization of resource files. A corporate website could internationalize its content in different languages such as German and Japanese, simply by translating the XML content and leaving the stylesheets unchanged. A given output format, such as HTML, PDF, PostScript, or the like, has its own associated XSLT stylesheet. Thus, for a given XML document, a first XSLT stylesheet must be created to generate HTML, a second XSLT stylesheet must be created to generate PDF, a third XSLT stylesheet must be created to generate WML, and so forth. Because of the need to have a unique stylesheet for every output format, authoring XSLT stylesheets is an extremely complex and time-consuming task. Many designers have little if any experience in this process, and a single stylesheet error often prevents the generation of any useful output. Visual data mapping tools have been created to accelerate the implementation of XSLT stylesheets. These tools, however, are only useful to author a particular stylesheet format (e.g., XSLT for transforming XML to HTML). There remains a long felt need in the art for solutions that can be used to create stylesheets for multiple output formats. The present invention addresses this need. BRIEF SUMMARY OF THE INVENTION It is a primary object of the present invention to provide a unified visual design environment in a data processing system to enable automatic generation of a plurality of stylesheets for different output formats. It is another more specific object of the invention to provide a system for automating writing of multiple different types of stylesheets through an integrated visual design environment that executes in a graphical user interface (GUI) of a data processing system. It is another object of the invention to provide for a single visual design environment in which a designer can create stylesheets through an intuitive user interface. A more specific object of the invention it to enable support for visual editing and generation of extensible Stylesheet Language (XSL) code, such as XSL code that enables XML content to be rendered into an HTML file, XSL:FO code that enables XML content to be rendered into a PDF file, and the like. With a single stylesheet design, developers can preview an output of a stylesheet transformation in one of several different formats, e.g., HTML, PDF, or others. In an embodiment, a method of and system for automatic writing of complex stylesheets preferably using an intuitive drag-and-drop user interface. By simply opening an existing structured data source (e.g., an XML document, an XML Schema, DTD, relational database, EDI document, a Web service, or the like), an appropriate content model appears in a given display panel, preferably in a tree-like controller. The designer then selects an element or attribute that he or she desires to appear in an output and drags it from the given display panel to a main output window. The designer then specifies how he or she would like the new node to be handled (e.g., as a new paragraph, image, table, or the like). A stylesheet, sometimes referred to as a “meta stylesheet,” is automatically generated (or is generated as the designer positions elements and attributes in the main output window). Typically, the meta stylesheet is maintained as an internal data representation, although it may be displayable if desired. According to the invention, two or more stylesheets are generated from the meta stylesheet and from within the integrated visual design environment, with each of the stylesheets being useful for generating the document being designed in a given output format. Thus, in a representative example, the two or more stylesheets include a first XSLT stylesheet for transforming an XML document into HTML, and a second XSLT stylesheet to facilitate transformation of the XML document into PDF via XSL:FO. Each of the stylesheets may be automatically previewed in the GUI by simply selecting a preview tab. Another control tab may be used to preview the output document rendered through the respective stylesheet. The foregoing has outlined some of the more pertinent features of the invention. These features should be construed to be merely illustrative. Many other beneficial results can be attained by applying the disclosed invention in a different manner or by modifying the invention as will be described. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a data processing system that includes the visual design environment of the present invention; FIG. 2 is a simplified illustration of an integrated visual design environment in which multiple stylesheets may be created according to the present invention; FIG. 3 illustrates a representative display of the visual design environment after the designer selects a schema; FIG. 4 illustrates a popup menu that may be used by a designer to create a document outline in the design view; FIG. 5 illustrates the design document in the visual design environment after the designer selects a given Create Contents option in the menu of FIG. 4. FIG. 6 illustrates an HTML preview of the document being designed; FIG. 7 illustrates a PDF preview of the document being designed; FIG. 8 illustrates a representative design document of FIG. 5 after including an attribute as a data-entry device; and FIG. 9 illustrates an HTML preview of the design document of FIG. 8. DETAILED DESCRIPTION OF AN EMBODIMENT The present invention is implemented in a data processing system such as shown in FIG. 1. Typically, a data processing system 10 is a computer having one or more processors 12, suitable memory 14 and storage devices 16, input/output devices 18, an operating system 20, and one or more applications 22. One input device is a display 24 that supports a window-based graphical user interface (GUI). The data processing system includes suitable hardware and software components (not shown) to facilitate connectivity of the machine to the public Internet, a private intranet or other computer network. In a representative embodiment, the data processing system 10 is a Pentium-based personal computer executing a suitable operating system such as Windows 98, NT, W2K, or XP. Of course, other processor and operating system platforms may also be used. Preferably, the data processing system also includes an XML application development environment 26. A representative XML application development environment is xmlspy® from Altova, Inc. An XML development environment such as Altova xmlspy® facilitates the design, editing and debugging of enterprise-class applications involving XML, XML Schema, XSL/XSLT, SOAP, WSDL, and Web services technologies. The XML development environment typically includes an XML parser 28, and a set of one or more XSLT processors 30a-n. A given XSLT processor may be provided as a native application within the XML development environment or as a downloadable component. According to the present invention, the XML development environment includes given software code (a set of instructions) for use in creating an integrated visual design environment (VDE) 25 in which multiple XSLT stylesheets 31a-n are generated. The visual design environment may be an adjunct to the data processing system GUI, or native to the GUI. In the past, it has not been possible to concurrently create different stylesheet formats within the same visual design space. The present invention solves this problem by providing the integrated visual design environment that is described below. If the XML development environment includes suitable XSLT processors, then the designer can also preview an output document using the generated stylesheet(s). Thus, in a representative embodiment, the XML development environment 26 includes an XSLT processor 30a for previewing an HTML document 32a (a document created by applying an XSLT stylesheet to an XML document), an XSL:FO processor 30b for previewing a PDF document 32b (a document created by applying an XSL:FO stylesheet to the XML document), an WML processor 30c for previewing a WML document 32c (a document created by applying a WML stylesheet to the XML document), and so forth. In the transformation process, according to instructions in the given XSLT stylesheet, the given processor 30 selects content from a data source (e.g., an XML document) and places it in the output document template, which is designed within a main output window as will be seen below. The selected content is usually placed as element content or as an attribute value. If the output document is intended for rendering on some output medium or as part of a processing chain that produces a document to be rendered, then the stylesheet can also be used to add presentation properties to the output document. As is well-known, the instructions for content selection, processing, placement, and formatting are all contained in the stylesheet. The visual design environment of the present invention enables the creation of multiple different types of stylesheets within a single visual workspace. FIG. 2 illustrates a representative graphical user interface 200 that includes the visual design environment comprising a number of graphical design elements. In a representative embodiment, the VDE comprises conventional control elements such as a menu bar 202 that contains a set of menus, and a toolbar 204 that contains icons for common commands. A main window 206 preferably includes a number of tabs. A design document tab 208 displays a document being designed together with its formatting. Dynamic components (i.e., content that comes from the XML document) preferably are displayed in terms of schema elements and attributes. Static components (e.g., images, non-XML text, etc.) preferably are actually displayed. Preferably, all components of the document are displayed with their formatting and layout properties. The main window 206 also includes a View Stylesheet tab 210 for each type of stylesheet format that may be created using the integrated visual design environment. Thus, in a representative example where the VDE is used to create both XSLT and XSL:FO stylesheets, there are two such tabs 210 with a first tab for viewing an XSLT stylesheet and a second tab for viewing an XSL:FO stylesheet. Preferably, the stylesheets are not editable in this display format. The main window also preferably includes a Preview tab 212 for each stylesheet format. Selecting the preview tab 212 preferably initiates a respective transformation process (using the underlying XSL processor), with the output of the transformation then displayed in the main window. Continuing with the above example, there are two such Preview tabs, one for the HTML output document, and one for the PDF output document. To facilitate the stylesheet design process, the integrated visual design environment also includes a schema window 214 that preferably displays a tree representation of a data source in terms of, for example: its elements and attributes, a list of all elements attributes for which global templates are possible, and optionally a list of all page layout components for a given output format (e.g., PDF). As will be described, preferably elements and attributes are dragged from the schema window 214 and placed (i.e., dropped) at a required location in the design document. The VDE may also include a text style window 216, and a block style window 218. The text style window preferably has a set of tabs, each with different groups of text formatting properties (such as font-weight and font-style). When text of an element containing text is selected in the design document, text-formatting properties are applied to the text via the properties in the text style window 216. If desired, some text style properties may be available as icons in the toolbar. The block style window 218 preferably has a set of tabs, each with different groups of block formatting properties (such as spacing before and after a block). When a block component is selected in the design document, block-formatting properties are applied to the block via the properties in the block style window 218. If the selected design document component is not a block, preferably the block style window is disabled. One of ordinary skill in the art will appreciate from the above description that the schema window 214 and the main window 206 facilitate an integrated visual design environment according to the present invention. The schema window 214 is a first display panel in which a data source is displayed, and the main window is a second display panel for displaying a document being designed from the data source. Typically, the data source is an XML document, however, this is not a limitation of the present invention. The data source may, alternatively, be a Document Type Definition (DTD), an XML Schema, a relational database, an Electronic Data Interchange (EDI) document, a Web service, or the like. A representative document design process is now described. Preferably, a data source is used as a starting point. In a representative embodiment, the data source is an XML document whose structure is displayed in the schema window. This provides the structural outline of the XML document in terms of its elements and attributes, which are loaded into and then available from the VDE. As used herein, the XML document is sometimes referred to as a working XML file. Preferably, the structure of the working XML file is displayed as a tree in the schema window. A document outline is then created in the main window. In particular, (in this illustrative example) XML content is selected by dragging an element or attribute from the schema tree. The dragged element/attribute is placed in the design document. The position where the element/attribute is dropped determines the location of that particular element/attribute in the design document. Because the actual content comes from the XML document and may vary depending on the XML content of the element/attribute, this type of content is known as dynamic content; its containing component is known as a dynamic component. The above-described process creates what is sometimes referred to herein as a “meta” stylesheet, as this stylesheet is useful as a source of two or more output stylesheets (such as a first XSLT stylesheet through which an XML document or other data source is rendered in HTML, a second XSLT stylesheet through which the XML document or other data source is rendered in WML, and so forth). The meta stylesheet typically is an internal data representation that can be saved in a given file format (e.g., an .sps format). Typically, the meta stylesheet may (but need not) conform with the XSLT programming language. According to the invention, the visual design environment includes code for generating, from the meta stylesheet, two or more stylesheets that are themselves useful in rendering the data source in two or more respective output formats using the respective stylesheets. As noted above, each of the stylesheets generated from the meta stylesheet may be previewed using the View Stylesheet tab, and (if an appropriate transformation engine is available) the output document rendered through that stylesheet may be viewed through the Preview tab. The following provides a more specific design example. In particular, a representative document design begins by having the designer select a schema. FIG. 3 illustrates a representative display. This schema creates a tree of the OrgChart (Organization Chart) schema in the VDE schema window, as well as entries for global templates and page layout features below the schema tree. In this example, a (contents) placeholder for a root element is also created in the design document output window. A working XML file preferably is used to preview how an XML file based on the selected schema will be processed by the meta stylesheet. As noted above, the inventive VDE preferably provides a set of two or more previews of the working XML file so that the designer can see how the meta stylesheet will process the XML. To assign a working XML file, the designer navigates using the appropriate control menus and selects a given XML file, such as NanonullOrg.xml, which is from a given folder. The working XML file, including its path, appears in the title bar. The user can then create a document outline in the design view as follows. In the schema window, the user expands the OrgChart element. The user then selects the /OrgChart/Name element and drags it in the design window. Preferably, this element is then positioned just after the (contents) placeholder. A blinking cursor preferably appears after the (contents) placeholder, and the dragged element becomes an arrow. When the mouse button is released, preferably a popup menu appears such as illustrated in FIG. 4. Assume now that the user selects the Create Contents option in the menu. The design document now looks as illustrated in FIG. 5. The Name element with a (contents) placeholder is inserted. The (contents) placeholder represents the content of the Name element. When the XML file is processed with this meta stylesheet, the XML content of the Name element will be displayed. The user can preview the XML file in the manner previously described. The HTML preview provides an accurate preview of HTML output such as illustrated in FIG. 6. A PDF preview is illustrated in FIG. 7. The XSLT stylesheet for the HTML output format is illustrated below (©2003 Altova GmbH): <?xml version=“1.0” encoding=“UTF-8”?> <xsl:stylesheet version=“1.0” xmlns:xsl=“http://www.w3.org/1999/XSL/Transform” xmlns:n1=“http://www.xmlspy.com/schemas/orgchart” xmlns:ipo=“http:/www.altova.com/IPO” xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance”> <xsl:template match=“/”> <html> <head /> <body> <xsl:for-each select=“n1:OrgChart”> <xsl:for-each select=“n1:Name”> <xsl:apply-templates /> </xsl:for-each> </xsl:for-each> </body> </html> </xsl:template> </xsl:stylesheet> The stylesheet for the PDF output format is illustrative below (©2003 Altova GmbH): <?xml version=“1.0” encoding=“UTF-8”?> <xsl:stylesheet version=“1.0” xmlns:xsl=“http://www.w3.org/1999/XSL/Transform” xmlns:fo=“http://www.w3.org/1999/XSL/Format” xmlns:n1=“http://www.xmlspy.com/schemas/orgchart” xmlns:ipo=“http://www.altova.com/IPO” xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance”> <xsl:variable name=“fo:layout-master-set”> <fo:layout-master-set> <fo:simple-page-master master-name=“default-page” page-height=“11in” page-width=“8.5in” margin-left=“0.6in” margin-right=“0.6in”> <fo:region-body margin-top=”0.79in” margin-bottom=“0.79in” /> </fo:simple-page-master> </fo:layout-master-set> </xsl:variable> <xsl:template match=“/”> <fo:root> <xsl:copy-of select=“$fo:layout-master-set” /> <fo: page-sequence master-reference=“default-page” initial-page-number=“1” format=“1”> <fo:flow flow-name=“xsl-region-body”> <fo:block> <xsl:for-each select=“n1:OrgChart”> <xsl:for-each select=“n1:Name”> <xsl:apply-templates /> </xsl:for-each> </xsl:for-each> </fo:block> </fo:flow> </fo:page-sequence> </fo:root> </xsl:template> </xsl:stylesheet> As noted above, according to the present invention the visual design environment includes code for generating these distinct stylesheets (preferably from the meta stylesheet, although this intermediate step is not necessarily required) that render the data source to a particular output format (HTML and PDF in the given example). The generated stylesheets can then be saved by selecting an appropriate menu command. Although not shown in detail, these stylesheets may then be exported for use in the data processing system or elsewhere in a conventional manner. As noted above, given element and attributes values may be included in the design document using the simple interface. Continuing with the example illustrated in FIG. 5, assume that the element CompanyLogo (as shown in the XML) has an href attribute, the value of which gives the location of the logo image. Assume it is also desired to have specified what image should be used as the logo. In such case, the designer can create the href attribute as an input field, and the location of the image can be entered. To accomplish this, in the schema window, the designer places a cursor between start tags of OrgChart and Name, and presses an Enter key or command to put the Name element on a next line. An href attribute is then dragged from the schema window into the design document (the main window). In this example, this attribute is dropped just after the OrgChart start tag. As a result, a popup menu (such as illustrated in FIG. 3) again appears and the designer (in this example) selects “Create Input Field”. The design document then looks as indicated in FIG. 8. FIG. 9 illustrates the HTML preview for the document at this point in the design process. In this example, the href attribute has been created as an input field, while the Name element was created as (contents). Although not illustrated in detail, one of ordinary skill will appreciate that the text and style blocks as well as other appropriate GUI commands and controls are included to facilitate production of the design document such as, among other things, including images, formatting the components, specifying text style properties, inserting tables, modifying table properties, inserting bookmarks and links, using conditional templates, and the like. Thus, for example, the processing of element content preferably is defined in the design document in the same way as the processing of attribute values is: drag the element from the schema tree, drop it into the design document as a component (of the meta stylesheet), specify further XSLT/Xpath processing, and apply a required formatting. As noted above, formatting can be applied to a stylesheet component using the text formatting and block formatting windows. Text formatting typically is applied to text, and it typically includes font sizes, font weights, and font colors. Block formatting typically is applied to components that have been explicitly defined as blocks, and include background colors for the block, spacing around the block, and borders for the block. A component can be explicitly defined as a block by assigning it a predefined format. To apply formatting to a component, preferably the following mechanisms may be used, either alone or in combination: applying a predefined format, applying text style properties, and/or applying block style properties. A skilled artisan will appreciate that the present invention provides numerous advantages over the prior art. According to the invention, a unified visual design environment automatically produces a plurality of stylesheets for different output formats, preferably without any external authoring tool. With prior art systems, if a designer wants to target a particular output format, he or she typically has to open a given HTML file, associate all elements from an XML tree, and then generate a stylesheet for use in that output format. He or she then has to do the same process all over again to target another output format (e.g., WML). These prior art approaches also typically require an external visual design tool to create the HTML page in the first place. Variants While the present invention has been described in the context of a visual design environment that includes a drag-and-drop interface, this is not a requirement of the invention. One of ordinary skill will appreciate that other techniques may be used to associate information from the data source representation into the output document format. Illustrative techniques include a clipboard, keyboard entry, an OLE data transfer mechanism, or the like. The particular orientation of the schema window, the main window and/or the text style and block style windows illustrated in FIG. 2 are not meant be taken to limit the present invention. The visual design environment may juxtapose the schema window and the main window to facilitate the drag-and-drop functionality in any convenient visual orientation or alignment. The principles of the present invention may also be generalized. As noted above, the “data source” from which the meta stylesheet is designed is not limited to an XML document. Various alternative data sources include, as noted above, an XML Schema, a DTD, a relational (or other structured) database, an EDI document, a Web service, or the like. In addition, one of ordinary skill will also appreciate that the XSLT stylesheets created by the invention may be generalized as any program code that renders the desired data (from the data source) to a particular output format. Thus, while an illustrative embodiment of the invention creates multiple XSLT stylesheets, this is not a limitation. The program code that renders the data to a particular output format may be generalized as any code written in a program language and selected from a set of available language templates including XSLT and others, such as: Java code, C# code, C++ code, Javascript, PHP, Perl, or any other convenient format. In this case the “meta” program code thus forms a superset, with the subset of this program code including the XSLT stylesheets described in the illustrative embodiment. A particular XSLT stylesheet may thus be considered an “instance” (e.g., a “version” or a “derivative”) of the meta program code. The present invention thus provides a visual design tool that allows a designer or other user to generate multiple output formats from a single data source through an integrated visual design environment that (as an intermediate step) selectively generates an appropriate program code instance (a given XSLT stylesheet, given Java code, given C# code, etc.) that renders the data to the particular output format. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Technical Field The present invention relates generally to data integration technologies and, in particular, to techniques for authoring stylesheets in an XML application development environment. 2. Description of the Related Art Organizations today are realizing substantial business efficiencies in the development of data intense, connected, software applications that provide seamless access to database systems within large corporations, as well as externally linking business partners and customers alike. Such distributed and integrated data systems are a necessary requirement for realizing and benefiting from automated business processes, yet this goal has proven to be elusive in real world deployments for a number of reasons including the myriad of different database systems and programming languages involved in integrating today's enterprise back-end systems. Extensible Markup Language (XML) technologies are ideally suited to solve advanced data integration challenges, because they are both platform and programming language neutral, inherently transformable, easily stored and searched, and already in a format that is easily transmittable to remote processes via XML-based Web services technologies. XML is a subset of SGML (the Structured Generalized Markup Language) that has been defined by the World Wide Web Consortium (W3C) and has a goal to enable generic SGML to be served, received and processed on the Web. XML is a clearly defined way to structure, describe, and interchange data. XML technologies offer the most flexible framework for solving advanced data integration applications. They do not, however, encompass the entire solution, in that a particular solution must still be implemented. Thus, XML technologies are not a standalone replacement technology, but rather a complementary enabling technology, which when bound to a particular programming language and database provide an elegant solution to a different problem. There are a number of ancillary technologies associated with XML. The extensible Stylesheet Language (XSL) consists of, among other things, the extensible Stylesheet Language Transformation (XSLT), a standardized language for transforming XML documents to simple output forms such as HTML or WML, and the extensible Stylesheet Language Formatting Objects (XSL:FO), an XML-based language for expressing advanced document layouts, employed by many popular formats including PDF and PostScript files. XSL decouples the contents of a document from its style (i.e., the document's layout and formatting). This allows a designer to either change the document's style without affecting the content, or to change the content while preserving the style. The transformation process from one data format to another involves processing an XML document and an XSL stylesheet in an XSL processor, which results in the generation of a new output document. An example of altering a document's style while preserving the content is multi-channel publishing. Using XSL, a single source of XML content can be published into a wide variety of customized output media, such as HTML, WML, PostScript, PDF, or any other information format, through the application of a stylesheet. An example of changing a document's content while preserving the style is internationalization and localization of resource files. A corporate website could internationalize its content in different languages such as German and Japanese, simply by translating the XML content and leaving the stylesheets unchanged. A given output format, such as HTML, PDF, PostScript, or the like, has its own associated XSLT stylesheet. Thus, for a given XML document, a first XSLT stylesheet must be created to generate HTML, a second XSLT stylesheet must be created to generate PDF, a third XSLT stylesheet must be created to generate WML, and so forth. Because of the need to have a unique stylesheet for every output format, authoring XSLT stylesheets is an extremely complex and time-consuming task. Many designers have little if any experience in this process, and a single stylesheet error often prevents the generation of any useful output. Visual data mapping tools have been created to accelerate the implementation of XSLT stylesheets. These tools, however, are only useful to author a particular stylesheet format (e.g., XSLT for transforming XML to HTML). There remains a long felt need in the art for solutions that can be used to create stylesheets for multiple output formats. The present invention addresses this need. | <SOH> BRIEF SUMMARY OF THE INVENTION <EOH>It is a primary object of the present invention to provide a unified visual design environment in a data processing system to enable automatic generation of a plurality of stylesheets for different output formats. It is another more specific object of the invention to provide a system for automating writing of multiple different types of stylesheets through an integrated visual design environment that executes in a graphical user interface (GUI) of a data processing system. It is another object of the invention to provide for a single visual design environment in which a designer can create stylesheets through an intuitive user interface. A more specific object of the invention it to enable support for visual editing and generation of extensible Stylesheet Language (XSL) code, such as XSL code that enables XML content to be rendered into an HTML file, XSL:FO code that enables XML content to be rendered into a PDF file, and the like. With a single stylesheet design, developers can preview an output of a stylesheet transformation in one of several different formats, e.g., HTML, PDF, or others. In an embodiment, a method of and system for automatic writing of complex stylesheets preferably using an intuitive drag-and-drop user interface. By simply opening an existing structured data source (e.g., an XML document, an XML Schema, DTD, relational database, EDI document, a Web service, or the like), an appropriate content model appears in a given display panel, preferably in a tree-like controller. The designer then selects an element or attribute that he or she desires to appear in an output and drags it from the given display panel to a main output window. The designer then specifies how he or she would like the new node to be handled (e.g., as a new paragraph, image, table, or the like). A stylesheet, sometimes referred to as a “meta stylesheet,” is automatically generated (or is generated as the designer positions elements and attributes in the main output window). Typically, the meta stylesheet is maintained as an internal data representation, although it may be displayable if desired. According to the invention, two or more stylesheets are generated from the meta stylesheet and from within the integrated visual design environment, with each of the stylesheets being useful for generating the document being designed in a given output format. Thus, in a representative example, the two or more stylesheets include a first XSLT stylesheet for transforming an XML document into HTML, and a second XSLT stylesheet to facilitate transformation of the XML document into PDF via XSL:FO. Each of the stylesheets may be automatically previewed in the GUI by simply selecting a preview tab. Another control tab may be used to preview the output document rendered through the respective stylesheet. The foregoing has outlined some of the more pertinent features of the invention. These features should be construed to be merely illustrative. Many other beneficial results can be attained by applying the disclosed invention in a different manner or by modifying the invention as will be described. | 20040121 | 20070403 | 20050721 | 98124.0 | 1 | THERIAULT, STEVEN B | METHOD AND SYSTEM FOR AUTOMATING CREATION OF MULTIPLE STYLESHEET FORMATS USING AN INTEGRATED VISUAL DESIGN ENVIRONMENT | SMALL | 0 | ACCEPTED | 2,004 |
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10,761,814 | ACCEPTED | Wood burning stove having pivoting baffle and method | A wood burning stove is provided. The combustion chamber in which the fire occurs has a baffle plate that is moveable to direct air flow through one of two different pathways from the combustion chamber to the chimney. When in a first position, the baffle plate forces the air and smoke to move through a first pathway; when in a second position, a by-pass pathway is opened, allowing air and smoke to move through a second pathway. The stove can have a door in the front wall, or the top wall, or both walls, to provide access to the combustion chamber. | 1-22. (Canceled) 23. A stove comprising: a stove body defining a combustion chamber; a chimney in air flow communication with the combustion chamber; a baffle plate disposed within the combustion chamber, the baffle plate spaced apart from at least a portion of the stove body to form a passage from the combustion chamber to the chimney; and an air manifold coupled to the baffle plate, the air manifold creating a secondary combustion area below the baffle plate; wherein the baffle plate and air manifold are moveable from a substantially horizontal closed configuration to an open configuration; wherein, when in the closed configuration, the baffle plate directs gases within the combustion chamber to flow from the combustion chamber, around the baffle plate, through the passage, and out the chimney; and wherein, when the baffle plate is in the open configuration, a by-pass pathway is formed, separate from the passage, between the combustion chamber and the chimney, so that gases within the combustion chamber flow from the combustion chamber, through the by-pass pathway, and out the chimney. 24. The stove according to claim 23, wherein the stove body further defines an access door. 25. The stove according to claim 24, wherein the access door is in a top wall of the stove body. 26. The stove according to claim 24, wherein the access door is in a front wall of the stove body. 27. The stove according to claim 23, wherein the stove body further defines a plurality of access doors. 28. The stove according to claim 23, wherein the air manifold is in air flow communication with a second air supply system, the air manifold being constructed and arranged to direct air from outside the stove into the secondary combustion area. 29. A stove comprising: a stove body defining a combustion chamber, the stove body including at least a front wall and a top wall each defining an opening for an access doors therein; a chimney in air flow communication with the combustion chamber; and a baffle plate disposed within the combustion chamber, the baffle plate being moveable from a closed configuration to an open configuration; wherein, when in the closed configuration, the baffle plate directs gases from the combustion chamber, through a first passage defined at least in part by the front wall and the top wall of the stove body, and into the chimney; and wherein, when the baffle plate is in the open configuration, the baffle plate directs gases from the combustion chamber, through a second passage, and into the chimney such that the gases do not exit the opening formed in either of the front wall and the top wall. 30. The stove according to claim 29, further comprising an air manifold positioned below the baffle plate, the combination of the baffle plate and air manifold creating a secondary combustion area below the baffle plate, the air manifold in air flow communication with a second air supply system, the air manifold constructed and arranged to direct air from outside the stove into the secondary combustion area. 31. The stove according to claim 30, wherein the air manifold is coupled to the baffle plate. 32. A method of adding fuel to a stove, comprising: moving a baffle plate of the stove from a substantially horizontal closed configuration to an open configuration, thus drawing heat and gases from the fire out through a by-pass pathway into a chimney of the stove; opening an access door positioned at a top wall of the stove; loading fuel through the door, past the baffle plate, and into the combustion chamber; moving the baffle plate into the substantially horizontal closed configuration; and closing the access door. | FIELD OF THE DISCLOSURE This disclosure relates generally to wood burning stoves. In particular, this disclosure relates to wood burning stoves having a baffle for regulation of air flow within the stove, and methods of using the stove. BACKGROUND OF THE DISCLOSURE Whether for providing heat, for purely decorative purposes, or for value enhancement, wood burning stoves have become commonplace in today's building trades for both residential and commercial applications for situations where a fireplace is not feasible or desired. In some instances, wood burning stoves have been inserted into fireplace boxes. Stoves are often preferred over open fireplaces because many wood stoves have the capability to heat large spaces efficiently. Most stoves are able to burn for extended periods of time, such as over night, without refueling or reloading, further enhancing the preference over fireplaces. With this extended burning of wood as the primary fuel comes the challenge of providing an efficient stove that meets the Environmental Protection Agency requirements and state agency requirements for emissions, including particulate material and gases. Many wood burning stoves utilize a catalytic combustor to finalize the burning process and reduce particulate materials and gases. However, the catalytic combustors can become fouled or otherwise rendered inefficient, especially when other than selected materials are burned within the stove. Additionally, the catalytic combustors are quite expensive and must be periodically replaced. In order to avoid using a catalytic combustor, many stove designs are aimed at providing optimum airflow within the burning chamber so that complete combustion, reduction of particulates and unburned gases, and optimum heat generation are obtained. The airflow patterns are generally created by the addition of various channels and/or baffles within the stove, in particular, within the main combustion chamber, to create a secondary combustion chamber. The use of fixed or stationary baffle plates for manipulating air flow within the combustion chamber are known for wood burning stoves, and are discussed, for example, in U.S. Pat. No. 4,766,876 (Henry et al.), U.S. Pat. No. 5,113,843 (Henry et al.), and U.S. Pat. No. 5,341,794 (Henry et al.), each of which is incorporated in its entirety herein by reference. Depending on the design of the various channels or baffles, loading of wood into the stove can be hampered. For example, some baffles are positioned extending essentially parallel to the top surface of the stove. If the stove is a top-loading stove, that is, where wood can be inserted into the combustion chamber through the top surface of the stove, such baffles hinder access to the combustion chamber. What is desired is an improved stove design having optimal air flow patterns to increase combustion efficiency, reduce emissions, and provide easy access to the combustion chamber. SUMMARY OF THE DISCLOSURE The present disclosure provides a stove, in particular, a wood burning stove, that has a baffle assembly disposed within to provide optimal air flow patterns within the stove. A portion of the baffle assembly is pivotable to provide easy access to the combustion chamber to allow loading of fuel into the stove. In particular, the stove includes a stove body which defines a stove exterior, a stove interior, and a combustion chamber disposed within the interior. A baffle plate is disposed within the combustion chamber, the baffle plate being moveable from a “closed” configuration to an “open” configuration. When in the “closed” configuration, the baffle plate is positioned substantially horizontally and is spaced apart from at least a portion of at least one wall. When in the “open” configuration, the baffle plate is positioned substantially vertically such that a by-pass pathway is created between a top access door and the combustion chamber. This allows for easy top-loading of fuel. When in the “closed” configuration, air within the combustion chamber flows from the combustion chamber, around the baffle plate, through a passage between the baffle plate and the stove body, and out a chimney. When in the “open” configuration, a by-pass pathway is formed separate from the passage, so that air within the combustion chamber flows from the combustion chamber, through the by-pass pathway, and out the chimney. The by-pass pathway does not exist if the baffle plate is in the closed configuration. Preferably, the baffle plate is pivotable. An air manifold is preferably present within the combustion chamber, having air flow communication with the exterior of the stove. In one embodiment, the air manifold provides a pivot point for the baffle plate. In one such embodiment, the baffle plate and the air manifold pivot together. It will also be understood that while a wood fueled stove will be described with respect to the preferred embodiments, the disclosure is not limited to wood burning structures, but could equally apply to stove using other fuel sources. Further, while the present disclosure will be described made of sheet metal material, the disclosure is not to be limited to any particular material, but could be used with other known constructions, such as ceramic and other known materials. These and other modifications of the disclosure will be understood by those skilled in the art in view of the following description of the disclosure, with reference to specific preferred embodiments thereof. BRIEF DESCRIPTION OF THE DRAWINGS Referring to the figures, wherein like numerals represent like parts throughout the several views: FIG. 1 is a front view of a stove of the present invention; FIG. 2 is a side view of a first embodiment of the stove incorporating the principles of this disclosure, illustrating the external stove structure and internal baffle assembly in a “closed” configuration; FIG. 3 is a side view of the stove of FIG. 2, illustrating the external stove structure and internal baffle assembly in an “open” configuration; FIG. 4 is an exploded schematic view of the baffle assembly shown in FIGS. 2 and 3; FIG. 5 is a front view of a portion of the baffle assembly shown in FIG. 4; FIG. 6 is a bottom view of the portion of the baffle assembly shown in FIG. 5; FIG. 7 is a side view of the portion of the baffle assembly shown in FIGS. 5 and 6; FIG. 8 is a partial side view of the stove of FIG. 2, illustrating the direction of air flow around the baffle assembly in a “closed” configuration; FIG. 9 is a partial side view of the stove of FIG. 3, illustrating the direction of air flow by-passing the baffle assembly in an “open” configuration; FIG. 10 is a top view of the stove of FIG. 2, with the baffle assembly in the “closed” configuration; FIG. 11 is a top view of the stove of FIG. 3, with the top access door open and the baffle assembly in the “open” configuration; FIG. 12 is a cut-away side view of a second embodiment of the stove incorporating the principles of this disclosure, illustrating the external stove structure and internal baffle assembly in a “closed” configuration; FIG. 13 is a side view of the stove of FIG. 12, illustrating the external stove structure and the internal baffle assembly in an “open” configuration; FIG. 14 is a front view of a portion of the baffle assembly shown in FIG. 12; FIG. 15 is a side view of the portion of the baffle assembly shown in FIG. 14; FIG. 16 is a bottom view of the portion of the baffle assembly shown in FIG. 14; FIG. 17 is a perspective view of the portion of the baffle assembly shown in FIG. 14; and FIG. 18 is an exploded schematic view of the baffle assembly shown in FIGS. 14 and 17. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Wood is generally burned in the stove, although other types of solid fuels can also be burned in the stove. The following description and figures are in reference to a wood burning stove, although it is to be understood that the function of the stove elements is not dependent on the type of fuel burned. A stove 10 is shown in FIG. 1. Stove 10 has an enclosed body 12 defined by first side wall 14, opposite second side wall 16, a top wall 17, a front wall 18, a bottom wall 19, and a back wall, not shown. Together, these various walls define an combustion chamber within the walls. Although body 12 is described with six walls (four periphery side walls, a top wall and a bottom wall), body 12 can be any shape. In general, the body 12 is defined by a top wall, a bottom wall, and at least one side wall. Body 12 is situated on a pedestal or foot 15, which elevates body 12 above the surface on which it is supported. Typically, stove 10 is metal, such as cast iron. A first door 20 is disposed within front wall 18, however, a door such as first door 20 can be provided in any of side walls 14, 16, front wall 18 or the back wall of stove 10. Door 20 is pivotally openable by hinges 22 attached to front wall 18. A handle 25 facilitates opening and closing of door 20. Door 20 can include a window 24 to allow viewing of the combustion chamber within the stove 10. A second door 30 is disposed within top wall 17 and is pivotally openable by hinges (not shown) attached to top wall 17. Door 30 may include a handle or other mechanism to facilitate opening and closing of door 30. Each of doors 20, 30 can be used to place fuel, such as wood logs, into the combustion chamber of stove 10. A stack, flue or chimney 40 is provided to allow the exhaust gases generated by the burning fuel to exit the stove 10. Included in stove 10 are various air intake apertures and channels, to provide air to the interior of the combustion chamber. Handles 42, 44 can be used to manipulate the flow of intake air. The above description of stove 10 has been fairly general. It is understood that any variation in the structure of stove 10 can be used with the moveable baffle assembly of the present disclosure. Stove 10, in accordance with the present disclosure, includes a handle 75 extending from body 12. Handle 75, which is part of a handle assembly, extends into the combustion chamber and is moveable as desired to manipulate the baffle assembly contained within the combustion chamber. The baffle assembly and its various elements will be now explained in detail, with reference to a first embodiment shown in FIGS. 2 and 3, and a second embodiment shown in FIGS. 12 and 13. Referring now to FIGS. 2, 3, 12, and 13, stove 10 is shown in side view with the baffle assembly of the present disclosure viewable through the stove body. The baffle assembly of the present disclosure generally includes a baffle plate 50, 150, an air manifold 60, 160, and mounting members 80, 180 fixed to the combustion chamber side of the side walls. A handle assembly 70, 170 is provided to facilitate moving baffle plate 50, 150. A fixed baffle plate 56, 156 is also included in the baffle assembly shown. FIGS. 4 through 7 show various elements of a first embodiment of the baffle assembly. In FIG. 4, the various elements are shown in exploded view; in FIGS. 5 through 7, a portion of the baffle assembly is shown. In particular, in accordance with the present disclosure and shown in each of FIGS. 4 through 7, a moveable baffle plate 50 is provided. Baffle plate 50 has a generally planar, solid face 52. Various strengthening features, such as ribs and the like, may be included in or on baffle plate 50. A fixed baffle plate 56, shown in FIG. 4, is also provided in the baffle assembly. Fixed baffle plate 56 is fixed to the combustion chamber side of the back wall of the stove 10. Baffle plates 50, 56 are typically made from a sheet of metal, such as steel or cast iron, although other materials, such as ceramic materials, can be used. Disposed proximate to baffle plate 50 is an air manifold 60 for providing and further manipulating air flow within the combustion chamber. The air manifold creates a secondary combustion area beneath the baffle plate and above the primary combustion area. Both the primary and secondary combustion areas are located in the combustion chamber. Air manifold 60 includes a first manifold section 62 and a second manifold section 64. In particular, first manifold section 62 is shown as an axial structure about which the manifold 60 can be pivoted, and second manifold section 64 is a D-shaped structure extending out from first section 62. Manifold sections 62, 64 are tubular structures that allow air flow there through. Air enters manifold 60 via intake 65 and exits manifold sections 62, 64 through apertures 68 disposed within manifold sections 62, 64. Preferably, a portion of air manifold 60, specifically a portion having intake 65, is in air flow communication with the exterior of the stove body 12. In one embodiment, intake 65 is connected to channels within the mounting members 80 that are connected to the exterior of the stove 10. These channels may meet the exterior at the stove sides, stove back, or at other locations. Baffle plate 50 is connected to second manifold section 64 at connection point 54 and to first manifold section 62 at connection point 55. Together, baffle plate 50, air manifold 60, and fixed baffle plate 56 manipulate the air and smoke flow within the combustion chamber of stove 10 so that optimum temperature and combustion are realized therein. Mounting members 80 are positioned adjacent to, and typically attached to, the combustion chamber side of the side walls. Mounting members 80 provide a seat or support against which the baffle plate 50 can rest when baffle plate 50 is in the “closed” position. Mounting members 80 may manipulate the air flow patterns somewhat. At least a portion of the mounting members 80 typically extends into the combustion chamber some distance from the wall on which it is attached. Although mounting members 80 are shown as two oppositely placed pieces (see FIG. 4), mounting member 80 can be a single structure positioned on only one side wall 14 of 16, or on the front wall 18, or on the back wall. Alternately, mounting member 80 can be a single structure that is positioned on two or more walls. Further, in some embodiments it may be desirable to incorporate fixed baffle plate 56 with mounting member 80, thus having one structure that provides the desired air flow pattern and supports the moveable baffle plate 50. The baffle assembly further includes a handle assembly 70 constructed to connect to, and move, baffle plate 50 and manifold 60 from the “open” to the “closed” configuration. Handle assembly 70 has a first position and a second position; when in the first position, the baffle plate 50 is in its “open” configuration, and when in the second position, the baffle plate 50 is in its “closed” configuration. Handle assembly 70 includes a first section 72, second section 74, and third section 76, which are connected together and to baffle plate 50. A handle 75 is connected to first section 72 and is disposed on the exterior of stove 10 so that a consumer can grab and move handle 75 as desired. Although shown with three sections 72, 74, 76, it is understood that any handle assembly 70 configuration can be used to move baffle plate 50. When the baffle assembly is disposed within the stove, baffle plate 50 is moveable, preferably pivotable, from an “closed” configuration to an “open” configuration. Baffle plate 50 and air manifold 60 are mounted within stove 10 in any manner to allow the desired movement from the “closed” configuration to the “open”configuration. In one embodiment, air manifold 60 is pivotally attached to mounting members 80, for example, in close proximity to intake 65. In such an attachment design, first manifold section 62 is an axis for rotation, or pivoting, of manifold 60. Because baffle plate 50 is attached to manifold 60 at points 54, 55, baffle plate 50 will move in congruence with manifold 60. In another embodiment, the pivoting of baffle plate 50 and manifold 60 are fixedly attached to handle assembly 70; this point of attachment is the pivot point. See for example, FIG. 7, in which reference numeral P designates a potential pivot point. FIGS. 14 through 18 show various elements of a second embodiment of the baffle assembly, in which the air manifold is expanded. In FIG. 18, the various elements are shown in exploded view; in FIGS. 14 through 17, a portion of the baffle assembly is shown. In particular, in accordance with the present disclosure and shown in each of FIGS. 14 through 18, a moveable baffle plate 150 is provided. Baffle plate 150 has a generally planar, solid face 152. Various strengthening features, such as ribs and the like, may be included in or on baffle plate 150. A fixed baffle plate 156, shown in FIG. 18, is also provided in the baffle assembly. As shown in FIG. 18, fixed baffle plate 156 is fixed to the combustion chamber side of the back and/or side walls of the stove 10 via rear mounting member 204. It is to be understood that fixed baffle plate 156 can alternatively be fixed to the rear portion of the mounting members 180. Baffle plates 150, 156 are typically made from a sheet of metal, such as steel or cast iron, although other materials, such as ceramic materials, can be used for baffle plates 150, 156. Disposed proximate to baffle plate 150 is an air manifold 160 for providing and further manipulating air flow within the combustion chamber. The air manifold creates a secondary combustion area beneath the baffle plate and above the primary combustion area within the combustion chamber. Air manifold 160 includes a first manifold section 162, a second manifold section 164, a third manifold section 200, and a fourth manifold section 201. In the illustrated embodiment, first, second, and third manifold sections 162, 164, 200 are shown as tubular structures connected to end pieces 205 about which the first, second, and third manifold sections 162, 164, 200 can be pivoted. A fourth, fixed, manifold section 201 is a tubular structure extending between, and fixed to, mounting members 180. Manifold sections 162, 164, 200, 201 are tubular structures that allow air flow there through. Air enters manifold 160 via intake 165 and exits manifold sections 162, 164, 200 through apertures 168 disposed within manifold sections 162, 164, 200. Air enters fourth manifold section 201 via intake 210 and exits through apertures 168 disposed within fourth manifold section 201. Preferably, a portion of air manifold 160, specifically a portion having intake 165, is in air flow communication with the exterior of the stove body 12. Additional intake 210 is in air flow communication with the fourth tubular section 201 and with the exterior of the stove body 12. In one embodiment, intakes 165, 210 are connected to channels 250, 260, respectively, within mounting members 180 that are connected to the exterior of the stove 10. These channels may be joined together under mounting members 180 and exit through the wall of the stove as a single channel, or they may exit separately. These channels may meet the exterior at the stove sides, stove back, or at other locations. Baffle plate 150 is connected to end pieces 205. Together, baffle plate 150, air manifold 160, and fixed baffle plate 156 manipulate the air and gas flow within the combustion chamber of stove 10 to create a secondary combustion area above the primary combustion area so that optimum temperature and combustion are realized in the stove. In one embodiment, insulation panels 202, 203 are included in the baffle assembly. Insulation panels 202, 203 are constructed of insulating material to reflect heat back into the combustion chamber from the baffle assembly and thereby maximize the temperature within the combustion chamber during all burn conditions, and thereby encouraging secondary and tertiary combustion above the fuel bed. In a further embodiment, the insulation panels 202, 203 may also provide structural support for the baffle plates 150, 156. The insulation panels 202, 203 may be made of any suitable insulating material. In one embodiment, the insulation panels 202, 203 are ceramic. Mounting members 180 are positioned adjacent to, and typically attached to, the combustion chamber side of the side walls. Mounting members 180 provide a seat or support against which the baffle plate 150 can rest when baffle plate 150 is in the “closed” position. Mounting members 180 may manipulate the air flow patterns somewhat. At least a portion of mounting members 180 typically extends into the combustion chamber some distance from the wall on which it is attached. Although mounting members 180 are shown as two oppositely placed pieces (see FIG. 18), mounting members 80 can be a single structure positioned on only one side wall 14 of 16, or on the front wall 18, or on the back wall. Alternately, mounting members 180 can be a single structure that is positioned on two or more walls. Further, in some embodiments it may be desirable to incorporate fixed baffle plate 156 with mounting members 180, thus having one structure that provides the desired air flow pattern and supports the moveable baffle plate 150. The baffle assembly further includes a handle assembly 170 constructed to connect to, and move, baffle plate 150 and manifold 160 from the “open” to the “closed” configuration. Handle assembly 170 has a first position and a second position; when in the first position, the baffle plate 150 is in its “open” configuration, and when in the second position, the baffle plate 150 is in its “closed” configuration. Handle assembly 170 includes a first section 172, second section 174, and third section 176, which are connected together and to baffle plate 150. A handle 175 is connected to first section 172 and is disposed on the exterior of stove 10 so that a consumer can grab and move handle 175 as desired. Although shown with three sections 172, 174, 176, it is understood that any handle assembly 170 configuration can be used to move baffle plate 150. When the baffle assembly is disposed within the stove, baffle plate 150 is moveable, preferably pivotable, from an “closed” configuration to an “open” configuration. Baffle plate 150 and air manifold 160 are mounted within stove 10 in any manner to allow the desired movement from the “closed” configuration to the “open” configuration. In one embodiment, air manifold 160 is pivotally attached to mounting members 180 through end pieces 205, for example, in close proximity to intake 165. In such an attachment design, the end pieces 205 provide an axis for rotation, or pivoting, of manifold 160. Because baffle plate 150 is attached to manifold 160, baffle plate 150 will move in congruence with manifold 160. In another embodiment, the pivoting of baffle plate 150 and manifold 160 are fixedly attached to handle assembly 170; this point of attachment is the pivot point. See for example, FIG. 15, in which reference numeral P designates a potential pivot point. Referring to FIGS. 8 and 9, partial side views of stove 10 are shown with the baffle plate 50 in the “closed” and “open” configurations, respectively. The pivot point for these embodiments is intake 65. In both FIGS. 8 and 9, the air flow pattern, mostly the flow pattern of smoke and combustion gases, is depicted by the arrows 300, 301. In FIG. 8, the baffle plate 50 is in the “closed” configuration with baffle plate 50 seated against mounting members 80. In this configuration, the baffle plate 50 is spaced apart from at least a portion of the front wall 18 forming a passage 400 from the combustion chamber to the chimney 40. The passage 400 may be formed in any location where the baffle plate is spaced apart from at least a portion of a side wall. Handle 75 is in a first position. Baffle plate 50, and air manifold 60, are substantially horizontal. Smoke and gases rise from the burning wood, (not shown, but which is typically on the base wall of the stove), and is directed by baffle plate 50 toward front wall 18. The smoke and gases flow generally parallel to baffle plate 50. The smoke and gases then pass through the passage 400, around and over baffle plate 50 and mounting members 80, and flow out chimney 40, as indicated by arrow 300. In FIG. 9, handle 75 is in a second position and the baffle plate 50 is in the “open” configuration with baffle plate 50 not seated against mounting members 80; baffle plate 50 is displaced from its seat on mounting members 80 and a by-pass pathway 100, separate from passage 400, is opened. In the position shown, baffle plate 50 and air manifold 60 are substantially vertical, and the by-pass pathway 100 is formed between the “open” baffle plate 50 and the fixed baffle 56. With baffle plate 50 pivoted to the “open” position, smoke and gases are able to move through by-pass pathway 100, as indicated by arrow 301. The smoke and gases flow generally parallel to baffle plate 50 through by-pass pathway 100. In FIG. 9, stove 10 is also shown with door 30 opened to provide access from the exterior to the interior of stove 10. FIGS. 10 and 11 show schematic top views of stove 10. In FIG. 10, door 30 is closed, and baffle plate 50 and manifold 60 are in the “closed” configuration; in FIG. 11, door 30 is open, and baffle plate 50 and manifold 60 are in the “open” configuration. It can be seen that when in the “open” configuration, access into the combustion chamber of stove 10 is generally unobstructed. Fuel, such as wood, can be loaded into stove 10 by various methods. In one embodiment, first door 20 can be pivoted on hinges 22 to open an access port to the combustion chamber. Prior to opening door 20, handle 75 is optionally moved from its first position to its second position, thereby moving baffle plate 50 from the “closed” configuration to the “open” configuration. Moving baffle plate 50 to the “open” configuration will open a by-pass channel 100 to allow smoke and gases to pass from the combustion chamber, through by-pass channel 100, out chimney 40. In this embodiment, baffle plate 50 minimizes the amount of smoke that might exit through door 20 when door 20 is opened. In another embodiment, fuel is loaded through the second door 30, located in top wall 17. Handle 75 is moved from its first position to its second position, thereby moving baffle plate 50 from the “closed” configuration to the “open” configuration. Moving baffle plate 50 to the “open” configuration will open by-pass channel 100 to allow smoke and gases to pass from the combustion chamber, through by-pass channel 100, and out chimney 40. Further, moving baffle plate 50 to the “open” configuration will provide a generally unobstructed access to the interior so that wood can be lowered into the combustion chamber through door 30 in top wall 17. In this embodiment, baffle plate 50 not only minimizes the amount of smoke that might exit through door 30 when door 30 is opened, but the pivotable baffle plate 50 provides an area through which wood can be easily passed for top loading. The above specification has been provided to illustrate specific examples of embodiments incorporating the principles of this disclosure. Those skilled in the art will readily recognize other applications and configurations that fall within the scope of this disclosure. Since many embodiments of the disclosure can be made without departing from the spirit and scope of the disclosure, the disclosure resides in the claims hereinafter appended. | <SOH> BACKGROUND OF THE DISCLOSURE <EOH>Whether for providing heat, for purely decorative purposes, or for value enhancement, wood burning stoves have become commonplace in today's building trades for both residential and commercial applications for situations where a fireplace is not feasible or desired. In some instances, wood burning stoves have been inserted into fireplace boxes. Stoves are often preferred over open fireplaces because many wood stoves have the capability to heat large spaces efficiently. Most stoves are able to burn for extended periods of time, such as over night, without refueling or reloading, further enhancing the preference over fireplaces. With this extended burning of wood as the primary fuel comes the challenge of providing an efficient stove that meets the Environmental Protection Agency requirements and state agency requirements for emissions, including particulate material and gases. Many wood burning stoves utilize a catalytic combustor to finalize the burning process and reduce particulate materials and gases. However, the catalytic combustors can become fouled or otherwise rendered inefficient, especially when other than selected materials are burned within the stove. Additionally, the catalytic combustors are quite expensive and must be periodically replaced. In order to avoid using a catalytic combustor, many stove designs are aimed at providing optimum airflow within the burning chamber so that complete combustion, reduction of particulates and unburned gases, and optimum heat generation are obtained. The airflow patterns are generally created by the addition of various channels and/or baffles within the stove, in particular, within the main combustion chamber, to create a secondary combustion chamber. The use of fixed or stationary baffle plates for manipulating air flow within the combustion chamber are known for wood burning stoves, and are discussed, for example, in U.S. Pat. No. 4,766,876 (Henry et al.), U.S. Pat. No. 5,113,843 (Henry et al.), and U.S. Pat. No. 5,341,794 (Henry et al.), each of which is incorporated in its entirety herein by reference. Depending on the design of the various channels or baffles, loading of wood into the stove can be hampered. For example, some baffles are positioned extending essentially parallel to the top surface of the stove. If the stove is a top-loading stove, that is, where wood can be inserted into the combustion chamber through the top surface of the stove, such baffles hinder access to the combustion chamber. What is desired is an improved stove design having optimal air flow patterns to increase combustion efficiency, reduce emissions, and provide easy access to the combustion chamber. | <SOH> SUMMARY OF THE DISCLOSURE <EOH>The present disclosure provides a stove, in particular, a wood burning stove, that has a baffle assembly disposed within to provide optimal air flow patterns within the stove. A portion of the baffle assembly is pivotable to provide easy access to the combustion chamber to allow loading of fuel into the stove. In particular, the stove includes a stove body which defines a stove exterior, a stove interior, and a combustion chamber disposed within the interior. A baffle plate is disposed within the combustion chamber, the baffle plate being moveable from a “closed” configuration to an “open” configuration. When in the “closed” configuration, the baffle plate is positioned substantially horizontally and is spaced apart from at least a portion of at least one wall. When in the “open” configuration, the baffle plate is positioned substantially vertically such that a by-pass pathway is created between a top access door and the combustion chamber. This allows for easy top-loading of fuel. When in the “closed” configuration, air within the combustion chamber flows from the combustion chamber, around the baffle plate, through a passage between the baffle plate and the stove body, and out a chimney. When in the “open” configuration, a by-pass pathway is formed separate from the passage, so that air within the combustion chamber flows from the combustion chamber, through the by-pass pathway, and out the chimney. The by-pass pathway does not exist if the baffle plate is in the closed configuration. Preferably, the baffle plate is pivotable. An air manifold is preferably present within the combustion chamber, having air flow communication with the exterior of the stove. In one embodiment, the air manifold provides a pivot point for the baffle plate. In one such embodiment, the baffle plate and the air manifold pivot together. It will also be understood that while a wood fueled stove will be described with respect to the preferred embodiments, the disclosure is not limited to wood burning structures, but could equally apply to stove using other fuel sources. Further, while the present disclosure will be described made of sheet metal material, the disclosure is not to be limited to any particular material, but could be used with other known constructions, such as ceramic and other known materials. These and other modifications of the disclosure will be understood by those skilled in the art in view of the following description of the disclosure, with reference to specific preferred embodiments thereof. | 20040121 | 20070515 | 20050310 | 72890.0 | 1 | PRICE, CARL D | WOOD BURNING STOVE HAVING PIVOTING BAFFLE AND METHOD | UNDISCOUNTED | 1 | CONT-ACCEPTED | 2,004 |
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10,761,855 | ACCEPTED | Data input device and method for detecting lift-off from a tracking surface by laser doppler self-mixing effects | A data input device for use with a tracking surface having light-scattering properties. The device comprises a single laser configured to project a light beam onto the tracking surface. A portion of the light beam striking the tracking surface reflects back into a cavity of the laser and thereby alters at least one characteristic of the projected light beam. A detector associated with the laser detects the altered characteristic of the light beam projected by the laser. A controller responsive to the detector determines the relative distance between the device and the tracking surface as a function of the altered characteristic of the projected light beam detected by the detector. Another device comprises a laser projecting a light beam oriented substantially perpendicular to the tracking surface when the device is operating in a tracking mode. | 1. A data input device for use with a tracking surface, said tracking surface having light-scattering properties with respect to said device, said device comprising: a single laser having a cavity from which a light beam is projected, said laser being configured to project the light beam onto said tracking surface, at least a portion of the light beam striking said tracking surface reflecting back into the cavity of said laser and thereby altering at least one characteristic of the projected light beam; a detector associated with the laser for detecting said altered characteristic of the light beam projected by the laser; and a controller responsive to the detector for determining the relative distance between said device and said tracking surface as a function of the altered characteristic of the projected light beam detected by the detector. 2. A device as set forth in claim 1 wherein said at least one altered characteristic is a frequency shift in the projected light beam of the laser. 3. A device as set forth in claim 2 wherein a Doppler waveform of said projected light beam having at least one altered characteristic has a frequency proportional to the speed of any relative displacement between the tracking surface and the device. 4. A device as set forth in claim 2 wherein a Doppler waveform of said projected light beam having at least one altered characteristic has an asymmetrical waveform indicating the direction of movement of the tracking surface and the device relative one another. 5. A device as set forth in claim 4 wherein a Doppler waveform of said projected light beam having at least one altered characteristic has a rise time longer than its fall time, indicating that the tracking surface and device are moving relatively toward one another. 6. A device as set forth in claim 4 wherein a Doppler waveform of said projected light beam having at least one altered characteristic has a rise time shorter than its fall time, indicating that the tracking surface and device are moving relatively away from one another. 7. A device as set forth in claim 1 wherein said at least one altered characteristic is a modulation of power output of the projected light beam of the laser. 8. A device as set forth in claim 7 wherein a Doppler waveform of said projected light beam having at least one altered characteristic has an amplitude proportional to the amount of light received by the detector. 9. A device as set forth in claim 1 further comprising a housing, said single laser and detector mounted on said housing. 10. A device as set forth in claim 9 wherein said housing is adapted to contact said tracking surface. 11. A device as set forth in claim 9 wherein said laser and said detector are mounted adjacent each other on at least one of a micro-chip, a printed circuit board (PCB) and a leadframe. 12. A device as set forth in claim 1 wherein the laser draws less than about 1.0 mW (1.3 μhorsepower). 13. A device as set forth in claim 1 wherein said laser is a solid-state device. 14. A device as set forth in claim 14 wherein said laser is at least one of a vertical cavity surface emitting laser (VCSEL) and an edge-emitting laser (EEL). 15. A device as set forth in claim 1 wherein said tracking surface is human skin. 16. A device as set forth in claim 1 wherein the detector associated with the laser monitors the intensity of the laser. 17. A device as set forth in claim 1 further comprising an optic positioned between the laser and the tracking surface for refracting the light beam between the tracking surface and the laser. 18. A data input device for use with a tracking surface, said tracking surface having light-scattering properties with respect to said device, said device comprising: a laser having a cavity from which a light beam is projected, said laser being configured to project the light beam onto said tracking surface, said light beam oriented substantially perpendicular to said tracking surface when said device is operating in a tracking mode, at least a portion of the light beam striking said tracking surface reflecting back into the cavity of said laser and thereby altering at least one characteristic of the projected light beam; a detector associated with the laser for detecting said altered characteristic of the light beam projected by the laser; and a controller responsive to the detector for determining the relative distance between said device and said tracking surface as a function of the altered characteristic of the projected light beam detected by the detector. 19. A device as set forth in claim 18 wherein said at least one altered characteristic is a frequency shift in the light beam projected by the laser. 20. A device as set forth in claim 18 wherein said at least one altered characteristic is a modulation of power output of the light beam projected by the laser. 21. A device as set forth in claim 18 further comprising a housing, said laser and detector mounted on said housing. 22. A device as set forth in claim 21 wherein said housing is adapted to contact said tracking surface and orient said laser with respect to said tracking surface. 23. A device as set forth in claim 18 wherein said tracking surface is human skin. 24. A method comprising: projecting a light beam onto a tracking surface from a laser having a laser cavity, wherein a data input device includes said laser and laser cavity; receiving at least a portion of the light reflected by the tracking surface within the laser cavity; mixing said received reflected light with light generated within said laser cavity, said mixing thereby altering at least one characteristic of said projected light beam; projecting a light beam with said at least one altered characteristic from said laser cavity; detecting said at least one altered characteristic of the light beam; and determining the relative distance between said device and said tracking surface as a function of the at least one altered characteristic of the projected light beam. 25. The method as set forth in claim 24 further comprising altering data output of the data input device as a function of the determined relative distance. 26. The method as set forth in claim 24 wherein said projected light beam is reflected from a reference surface prior to said detecting. 27. The method as set forth in claim 26 wherein said reference surface is mounted on said data input device. 28. The method as set forth in claim 27 wherein said reference surface is a housing of said data input device. 29. The method as set forth in claim 24 further comprising determining the speed of any relative displacement between the tracking surface and the device. 30. The method as set forth in claim 29 further comprising altering the data output of the data input device as a function of the speed. 31. The method as set forth in claim 24 wherein said detected at least one altered characteristic of the light beam is frequency. 32. The method as set forth in claim 24 wherein said detected at least one altered characteristic of the light beam is light intensity. 33. The method as set forth in claim 24 further comprising comparing said relative distance between said device and said tracking surface to a lift-off detection distance and altering the data output of the data input device as a function of the comparison. 34. The method as set forth in claim 33 further comprising (i) suspending tracking of relative movement between said device and said tracking surface when said device is spatially separated from said tracking surface by at least the lift-off detection distance and (ii) maintaining tracking of relative movement between said device and said tracking surface when said device is spatially separated from said tracking surface by less than said lift-off detection distance. 35. The method as set forth in claim 33 wherein said lift-off detection distance is no more than about 4 millimeters (0.16 inch). 36. The method as set forth in claim 35 wherein said lift-off detection distance is no more than about 4 millimeters (0.16 inch) and at least about 0.5 millimeter (0.02 inch). 37. The method as set forth in claim 36 wherein said lift-off detection distance is no more than about 3 millimeters (0.12 inch) and at least about 0.5 millimeter (0.02 inch). 38. A data input device for use with a tracking surface, said device comprising: a single laser having a cavity from which a light beam is projected, said laser being configured to project the light beam onto said tracking surface, at least a portion of the light beam striking said tracking surface reflecting back into the cavity of said laser and thereby altering at least one characteristic of the projected light beam; a detector associated with the laser for detecting said at least one altered characteristic of the light beam projected by the laser; and a controller responsive to the detector for operating the device in a tracking mode or a non-tracking mode depending upon said at least one altered characteristic of the projected light beam. 39. A device as set forth in claim 38 wherein said at least one altered characteristic is a frequency shift in the projected light beam of the laser. 40. A device as set forth in claim 38 wherein said at least one altered characteristic is a modulation of power output of the projected light beam of the laser. | TECHNICAL FIELD Embodiments of the present invention relate to the field of computer input devices, and particularly data input devices, such as a mouse or optical pen, employing light striking a tracking surface for detecting movement. In particular, embodiments of this invention relate to data input devices capable of generating laser light beams altered by Doppler self-mixing effects, detecting altered characteristics of the projected laser light beams, and determining the relative distance between the data input device and the tracking surface as a function of the altered characteristic of the projected light beam. BACKGROUND OF THE INVENTION Previous computer input devices, such as mice, include rotatable balls mounted within a housing, yet rotatably engaging a surface. As the housing of such a mouse translates across the surface, the ball rotates within the housing, engaging horizontally and vertically situated wheels that rotate against the ball, thereby indicating horizontal (e.g., side to side or x-direction) and vertical (e.g., back and forth or y-direction) movement of the mouse across the surface. When the device is lifted from the surface, hereinafter referred to as lift-off, the ball stops rotating and the horizontal and vertical movement information provided by the wheels stops. This feature is particularly useful to a user who has reached a point where the device can no longer move with respect to the tracking surface, but the user would like to continue tracking in that particular direction on screen. By lifting the device off of the tracking surface, the user can reposition the device, while the cursor remains stationary because tracking is suspended during lift-off. When tracking resumes, horizontal and vertical wheel rotation translates into an on-screen visual image of a cursor that responds to movement of the device. Because such devices have a moving ball passing through a hole in the housing, such devices often become contaminated with dust and dirt, which may yield inaccurate or intermittent cursor tracking. Moreover, the tracking surface and ball require sufficient friction between the two to cause the ball to rotate when the housing translates over the surface. To help provide such friction and minimize contamination of the device, specialized tracking surfaces (e.g., mouse pads) are typically used. Thus, a major limitation of such a device is that it requires a tracking surface with particular characteristics, such as adequate friction and cleanliness, which are not readily found on all surfaces that would otherwise be useful for tracking. Building upon these primarily mechanical tracking devices, optical tracking devices have become available. Such devices optically track movement of a surface, rather than mechanically as with the devices described immediately above. These optical tracking devices may avoid some of the drawbacks associated with the mechanical devices described above. In particular, optical devices typically do not require wheels in contact with a movable ball, which acts as a common collection point for dust and dirt. Instead, the movable ball may be covered with a distinct pattern. As the ball rotates over a surface due to movement of the input device, photodetectors facing another side of the ball collect information about the movement of the ball's distinct pattern as the ball rotates. A tracking engine then collects this information, determines which way the pattern is translating and translates a cursor on the screen similarly, as described above. Lift-off detection is performed as discussed above, when lifted the ball stops moving so the device stops tracking. These devices offer improvements over previous designs by eliminating moving parts (the wheels) and changing the ball detection interaction from mechanical to optical. However, such devices lack the ability to track on any surface, requiring a suitable frictional interface between the ball and the surface. Moreover, these devices still require one moving part, namely, the ball. In addition, aliasing artifacts may cause the cursor to skip, rather than move fluidly. Still other optical devices place a pattern on the tracking surface (e.g., a mouse pad), rather than on the rotatable ball, thereby using the mouse pad to generate optical tracking information. Although such devices are able to eliminate the moving ball, they are less universal by requiring a specific tracking surface to operate. Other more recent optical tracking devices eliminate the need for a patterned ball or mouse pad. One such device utilizes an LED to project light across the tracking surface at a grazing angle relative to the tracking surface. The mouse then collects tracking information by two methods: first, by tracking changes in color on the tracking surface by any pattern that may appear on the tracking surface; or second, by detecting dark shadows cast by high points in the surface texture, which appear as dark spots. Such an LED device eliminates the moving ball of previous devices, and is useful on a variety of surfaces. However, smooth surfaces with little color variation, such as surfaces with a fine microfinish similar to glass or clear plastic, may prove difficult to track upon. More importantly, these systems lack the ability to detect when the device has been removed from the tracking surface (lift-off) for freezing the cursor. Without freezing the cursor upon lift-off, the tracking device will continue to track when the user is attempting to reposition the device on the tracking surface while leaving the cursor in the same place. SUMMARY OF THE INVENTION Accordingly, a data input device capable of generating laser light beams altered by Doppler self-mixing effects, detecting altered characteristics of the projected light beams, determining the relative distance between the data input device and the tracking surface as a function of the altered characteristic of the projected light beam is desired to address one or more of these and other disadvantages. In accordance with one aspect of the invention, a data input device for use with a tracking surface having light-scattering properties with respect to the device is disclosed. The device comprises a single laser having a cavity from which a light beam is projected. The laser is configured to project the light beam onto the tracking surface. At least a portion of the light beam striking the tracking surface reflects back into the cavity of the laser and thereby alters at least one characteristic of the projected light beam. A detector associated with the laser detects the altered characteristic of the light beam projected by the laser. A controller responsive to the detector determines the relative distance between the data input device and the tracking surface as a function of the altered characteristic of the projected light beam detected by the detector. In another aspect of the invention, a data input device for use with a tracking surface having light-scattering properties with respect to the device is disclosed. The device comprises a laser having a cavity from which a light beam is projected onto the tracking surface. The light beam is oriented substantially perpendicular to the tracking surface when the device is operating in a tracking mode. At least a portion of the light beam striking the tracking surface reflects back into the cavity of the laser substantially as set forth above. The device further comprises a detector and a controller substantially as set forth above. In yet another aspect of the invention, a method comprises projecting a light beam from a laser having a laser cavity onto a tracking surface and receiving at least a portion of the light reflected by the tracking surface within the laser cavity. The method further comprises mixing the received reflected light with light generated within the laser cavity. The mixing thereby alters at least one characteristic of the projected light beam. A light beam with the at least one altered characteristic is projected from the laser cavity. The method further comprises detecting the at least one altered characteristic of the light beam and determining the relative distance between the laser cavity and the tracking surface as a function of the at least one altered characteristic of the projected light beam. In still another aspect of the invention, a data input device for use with a tracking surface comprises a single laser and a detector generally as set forth above. The device further comprises a controller responsive to the detector for operating the device in a tracking mode or a non-tracking mode depending upon the at least one altered characteristic of the projected light beam. Alternatively, the invention may comprise various other methods and apparatuses. Other features will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic of a device of the present invention engaging a tracking surface; FIG. 2 is a schematic of the device of FIG. 1 lifted from the tracking surface; FIG. 3 is a schematic of another device of the present invention lifted from the tracking surface; FIG. 4 is a schematic of yet another device of the present invention engaging the tracking surface; FIG. 5 is a schematic of the device of FIG. 4 lifted from the tracking surface; FIG. 6 is a schematic of the device of FIG. 1 engaging a tracking surface of human skin; FIG. 7 is an example of a frequency wave of a projected laser light beam having at least one altered characteristic; and FIG. 8 is a block diagram illustrating one example of a suitable computing system environment in which the invention may be implemented. Corresponding reference characters indicate corresponding parts throughout the drawings. DETAILED DESCRIPTION OF THE INVENTION Referring first to FIGS. 1 and 2, a data input device, generally indicated 21, for use with a tracking surface 25 is depicted. Although such a device 21 is typically capable of tracking relative movement between the device and the tracking surface 25 (described above as horizontal-vertical movement or x-y movement), it should be noted here that a focus of the present disclosure specifically involves lift-off detection. Any of the various tracking schemes known in the relevant art may be coupled with the teaching of the present invention for lift-off detection. It should be noted here that the terms “lift-off” or “lifting” the device 21 additionally comprise either lifting, or moving, the tracking surface 25 away from the stationary device (e.g., FIG. 6), or lifting the device away from the tracking surface (e.g., FIGS. 2, 3 and 5). In addition, referring to relative movement between the device 21 and the tracking surface 25 in a z-direction may comprise movement of the device (e.g., a mouse moving over a mouse pad), movement of the tracking surface (e.g., a moving trackball or human skin moving in the path of a laser light beam), or movement of both the tracking surface and the device. The device 21 generally comprises a single laser 29 for projecting a laser light beam A onto the tracking surface 25. A portion of the light beam A striking the tracking surface 25 reflects back as light beam B into a cavity 31 of the laser and thereby alters at least one characteristic of the subsequently projected light beam C (see FIGS. 1 and 2). Mixing of the reflected light beam B with the light generated within the cavity 31 of the laser 29 is known in the art as self-mixing. Self-mixing is well documented in scientific literature (e.g., Wang et al., Self-Mixing Interference Inside a Single-Mode Diode Laser for Optical Sensing Applications, JOURNAL OF LIGHTWAVE TECHNOLOGY 1577-1587, Vol. 12, No. 9, 1994.) and will not be discussed in great detail here. Suffice it to say that mixing of laser light B backscattered (i.e., reflected back) from the tracking surface 25 and into the cavity 31 of the laser 29 will alter the output of light beam C of the laser. By detecting even small alterations in the output C of the laser 29, the movement of the tracking surface 25 relative to the laser cavity 31, and in turn the device 21 itself, may be understood. Once this relative movement is understood in real time, both the speed and the position of the laser 29 and thus the device 21, relative to the tracking surface 25 may be readily ascertained, as will be discussed below in greater detail. The device 21 further comprises a detector 35 associated with the laser 29 for detecting light beam C projected by the laser and having at least one altered characteristic. The detector 35 and laser 29 may be mounted separately in the device 21 as depicted in FIGS. 1-3, or the laser and the detector may be mounted adjacent each other on a substrate 37, such as a micro-chip, a printed circuit board (PCB) or a leadframe, as depicted in FIGS. 4 and 5. Many lasers 29 include a detector 35 within the laser itself for use in monitoring the intensity of the laser light. When available, such detectors 35 may be utilized rather than adding an entirely new detector for use with the laser 29. Detectors 35 may include photodetectors, CCDs (charge-coupled devices), CMOS (complementary metal-oxide semiconductor) technology or other detector arrays that are capable of both the bandwidth and spectral requirements mandated by the laser 29. The device 21 further comprises an optic 39 positioned between the laser 29 and the tracking surface 25 for refracting the light beams (A, B, and in some embodiments C) between the tracking surface and the laser. Although the device 21 will function properly without an optic 39, the optic in this embodiment provides additional focusing and guidance of the light beams, ensuring that the signal reaching the detector 35 is strong. In addition, the device 21 comprises a controller 41 responsive to the detector 35 for determining the relative distance D between the device and the tracking surface 25 as a function of the at least one altered characteristic of the projected light beam C. The at least one altered characteristic of the light beam C may include a Doppler waveform frequency shift, Doppler waveform asymmetry, or changes in amplitude of the Doppler waveform, as discussed in detail below. In addition, the controller 41 is responsive to the detector 35 for operating the device 21 in a tracking mode or a non-tracking mode, depending upon the at least one altered characteristic of the light beam C. The device 21 further comprises a housing 45 for containing and protecting the components of the device. The housing 45 includes a support surface 47 adapted to engage the tracking surface 25 during a tracking mode of the device 21. The housing 45 may take any form, without departing from the scope of the claimed invention. For example, the housing 45 may be in the shape of a mouse, a trackball, an optical pen or any other data input device 21. The housing 45 further comprises an aperture 49 covered by a transparent window 51 that allows the light beam A to pass through the housing and fall upon the tracking surface 25, while limiting the ability of dust and dirt to enter the housing. Referring now to FIG. 3, the housing 45 may further comprise a field stop 55, or reference surface, limiting the direction in which the light beam B reflected from the tracking surface 25 can strike the detector 35. In this example, the light beam B reflected by the tracking surface 25 does not fall directly upon the detector 35. As depicted in FIG. 3, a reference surface 55 acts as a field stop, limiting light beam B′ from directly reflecting from the tracking surface 25 to the detector 35. The reference surface 55 may also be incorporated into the housing 45 itself, as a part of the transparent window 51, which partially transmits light and partially reflects light (see FIGS. 1 and 2), thereby eliminating the need for an additional reference surface. Detecting only light reflected by the reference surface helps minimize any noise or signal aberrations introduced by features of the tracking surface 25. Without such a separate reference surface, such as the device 21 of FIGS. 1 and 2, however, reflected light beam B, or ambient light reflected between the device 21 and the tracking surface 25, may reach the detector 35, increasing the noise in detected signals. Repositioning or resizing the reference surface 55 depending upon the dimensions of the device 21 or arrangement of the device components is within the skill of one skilled in the art and will not be discussed in great detail here. The device 21 may incorporate a variety of different lasers 29, as long as the lasers are capable of exhibiting the self-mixing phenomenon. Exemplary lasers 29 will draw as little power as possible. For instance, a suitable laser 29 draws less than about 1.0 mW (1.3 μhorsepower) of power. This ensures that the laser 29 may be used in a cordless device application without unduly limiting the battery life of the device. The eye-safety regulation is another consideration factor in limiting the output power from the laser. In particular, the laser 29 may also be a solid-state device, such as a vertical cavity surface emitting laser (VCSEL) or an edge-emitting laser (EEL). A gas-based laser, such as a Helium-Neon (He—Ne) laser, may also be used. Other lasers and sources of laser, or coherent, light capable of exhibiting self-mixing phenomena may also be utilized without departing from the scope of the claimed invention. Most tracking surfaces 25 will reflect a sufficient amount of light beam B back to the laser cavity 31 because they are optically rough, having adequate light-scattering properties with respect to the device 21. An optically rough surface scatters laser light in many directions, making the orientation of the laser 29 with respect to the tracking surface 25 relatively unimportant. For example, for most tracking surfaces 25, the light beam A may be oriented at any angle relative to the tracking surface because the optically rough tracking surface backscatters laser light in many directions, including back toward the laser 29. The location of the laser cavity 31 relative to this angle, therefore, is relatively unimportant, as long as the laser cavity receives a small portion of the laser light beam reflected from the tracking surface 25. For example, optically rough surfaces include many common tracking surfaces 25, including paper, wood, metal, fabric, certain plastics and human skin. Only surfaces that are perfectly reflective, i.e., mirror-like, such as a ground and polished, optic-quality, flat, transparent glass, are insufficiently rough to backscatter laser light in many directions. Such surfaces that are not optically rough will act as a mirror and only reflect laser light exactly opposite the angle of incidence of the laser 29. For the present device 21 to detect lift-off from such a tracking surface 25, the laser 29 and detector 35 may be oriented such that the reflected laser light beam B reenters the laser cavity 31 for self-mixing and the altered laser light beam C strikes the detector. One such configuration allows for self-mixing with a perfectly reflective tracking surface 25, even without backscattering in many directions, wherein the laser 29 is oriented substantially perpendicular to the tracking surface 25 when the device 21 is operating in a tracking mode (see FIGS. 4 and 5). Moreover, the detector 35 is oriented perpendicular to the tracking surface 25 and located behind the laser 29, such that it can detect the at least one altered characteristic of light beam C projected from the rear of the laser. In one example, an edge-emitting laser (EEL) 29 may have its detector 35 located behind the laser. By orienting the light beam A and detector 35 in alignment substantially perpendicular to the tracking surface 25, a portion of the light beam B striking the tracking surface reflects back into the cavity 31 of the laser 29 and thereby alters at least one characteristic of the projected light beam C. Referring now to FIG. 6, a device 21 is depicted wherein the tracking surface 25 is human skin. In particular, the tracking surface 25 shown is a human finger. This device 21 demonstrates that the device itself may be stationary while the tracking surface 25 moves relative to the device. The functioning of the device components, such as the laser 29, the detector 35 and the controller 41 are identical. A device 21 as depicted in FIG. 6 allows the user to move his hand, the tracking surface 25, over the device such that when the finger moves away from the device, the detector 35 and controller 41 are able to detect lift-off and stop tracking, respectively. Turning now to specifics of the detected at least one altered characteristic of light beam C, a frequency shift is one of the altered characteristics of the light beam that may allow for determining the distance D between the device 21 and the tracking surface 25. The Doppler waveform 61 depicted in FIG. 7 is such a waveform, wherein the x-axis indicates time in micro-seconds (ms) and the y-axis indicates laser intensity in milli-volts (mV). The projected light beam C created by self-mixing within the laser cavity 31 has a component with frequency proportional to the magnitude of the velocity, or speed, of any relative displacement between the tracking surface 25 and the device 21. For example, as the relative displacement between the device 21 and the tracking surface 25 increases, the Doppler waveform 61 indicates a corresponding increase in frequency, thereby bringing the peaks and troughs of the waveform closer to one another. In contrast, as the relative displacement between the device 21 and the tracking surface 25 decreases, the frequency of the Doppler waveform 61 indicates a corresponding decrease in frequency, thereby pushing the peaks and troughs of the waveform further from one another. Therefore, by detecting and monitoring the frequency of the Doppler waveform 61, the relative speed between the device 21 and the tracking surface 25 is known. Once known, the speed (which is proportional to the Doppler waveform frequency) may be integrated over time to calculate the relative displacement between the device 21 and the tracking surface 25. Another monitored characteristic of the Doppler waveform 61 of the projected light beam C is the direction of any asymmetry in the Doppler waveform 61, which indicates the direction of relative movement between the tracking surface 25 and the device 21. For example, for the waveform 61 depicted in FIG. 7, the rise time R of each cycle of the waveform is longer than the fall time F of each cycle of the waveform. Such a waveform indicates that the tracking surface 25 and device 21 are moving relatively toward one another. Conversely, a device 21 exhibiting a Doppler waveform having an altered characteristic of light beam C having a rise time R shorter than its fall time F (not shown) indicates that the tracking surface 25 and device 21 are moving relatively away from one another. Therefore, by detecting and monitoring the shape of the Doppler waveform 61, namely the length of its rise and fall times, the direction of relative displacement between the device 21 and the tracking surface 25 is known. Moreover, one skilled in the art would readily understand how to switch the waveform asymmetry to indicate a particular relative direction. An additional monitored characteristic of the projected light beam C is the modulation of power output of the laser 29. Self-mixing in the laser cavity 31 will induce changes in the power output of the laser 29, which will in turn induce changes in the amount of laser light projected by the laser. To detect and measure these changes in output, the present invention turns again to the Doppler waveform 61 of the projected light beam C having at least one altered characteristic. Specifically, the power of the Doppler component of the laser 29 is proportional to the amount of light reflected off the surface and received by the detector 35, which is represented by the amplitude O of the Doppler waveform 61. As this amplitude O increases, more reflected laser light is reaching the detector 35, resulting in stronger self-mixing within the laser cavity 31, which further indicates that the device 21 and tracking surface 25 are moving relatively closer to one another. Conversely, as amplitude O decreases, less laser light is reaching the detector 35, indicating less self-mixing within the laser cavity 31, which further indicates that the device 21 and tracking surface 25 are moving relatively apart from one another. Therefore, by detecting and monitoring the amplitude O of the Doppler waveform 61, which indicates movement of the device 21 and tracking surface 25 relative one another. Should the amplitude O fall below a threshold level, the device 21 may be deemed in lift-off mode and tracking suspended. The present invention further comprises a method comprising projecting a light beam A from a laser 29 of a data input device 21 onto a tracking surface 25 substantially as set forth above. A cavity 31 of the laser 29 receives light beam B reflected by the tracking surface 25 for mixing with the laser light generated within the laser cavity. The mixing thereby alters at least one characteristic of the projected light beam. The laser 29 then projects a light beam C having at least one altered characteristic, and a detector 35 detects the at least one altered characteristic of the light beam. The altered characteristic of the detected light beam C may be frequency or light intensity. The relative distance D between the device 21 and the tracking surface 25 may then be determined as a function of the detected at least one altered characteristic of the light beam C. Furthermore, the data output of the data input device 21 is altered as a function of the determined relative distance D between the device 21 and the tracking surface 25. For example, the method further comprises comparing the relative distance D between the device 21 and the tracking surface 25 to a lift-off detection distance and altering the data output of the data input device as a function of the comparison. The method further suspends tracking of relative movement between the device 21 and the tracking surface 25 when the device is spatially separated from the tracking surface by at least the lift-off detection distance. Conversely, the device 21 maintains tracking of relative movement between the device and the tracking surface 25 when the device is spatially separated from the tracking surface by less than the lift-off detection distance. In this manner, the device 21 only tracks relative movements of the tracking surface 25 when the tracking surface is in contact or close proximity to the device, as with traditional data input devices. Many different devices 21 may be constructed according to the above methods. For example, one device comprises a lift-off detection distance of no more than about 4 millimeters (0.16 inch). Another device comprises a lift-off detection distance of no more than about 4 millimeters (0.16 inch) and at least about 0.5 millimeter (0.02 inch). Yet another device comprises a lift-off detection distance of no more than about 3 millimeters (0.12 inch) and at least about 0.5 millimeter (0.02 inch). The method may additionally require that the light beam C projected from the laser 29 be reflected from a reference surface 55 prior to detecting. As discussed above, reflecting the light beam C having at least one altered characteristic from the reference surface 55 improves consistency because surface properties of the reference surface are known and constant, making them identical throughout use of the device 21, irrespective of the surface properties of the tracking surface 25. The reference surface 55 can be mounted on the data input device 21 or can be part of the housing 45 of the data input device. The method may also determine the speed of any relative displacement between the tracking surface 25 and the device 21 and may alter the data output of the data input device as a function of the speed. For example, moving the device 21 and the tracking surface 25 relative one another at different speeds may place the tracking device into different modes of use, as directed by the user. FIG. 8 shows one example of a general purpose computing device in the form of a computer 130. In one embodiment of the invention, a computer such as the computer 130 is suitable for use in the other figures illustrated and described herein. Computer 130 has one or more processors or processing units 132 and a system memory 134. In the illustrated embodiment, a system bus 136 couples various system components including the system memory. 134 to the processors 132. The bus 136 represents one or more of any of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, and a processor or local bus using any of a variety of bus architectures. By way of example, and not limitation, such architectures include Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect (PCI) bus also known as Mezzanine bus. The computer 130 typically has at least some form of computer readable media. Computer readable media, which include both volatile and nonvolatile media, removable and non-removable media, may be any available medium that can be accessed by computer 130. By way of example and not limitation, computer readable media comprise computer storage media and communication media. Computer storage media include volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. For example, computer storage media include RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and that can be accessed by computer 130. Communication media typically embody computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism and include any information delivery media. Those skilled in the art are familiar with the modulated data signal, which has one or more of its characteristics set or changed in such a manner as to encode information in the signal. Wired media, such as a wired network or direct-wired connection, and wireless media, such as acoustic, RF, infrared, and other wireless media, are examples of communication media. Combinations of the any of the above are also included within the scope of computer readable media. The system memory 134 includes computer storage media in the form of removable and/or non-removable, volatile and/or nonvolatile memory. In the illustrated embodiment, system memory 134 includes read only memory (ROM) 138 and random access memory (RAM) 140. A basic input/output system 142 (BIOS), containing the basic routines that help to transfer information between elements within computer 130, such as during start-up, is typically stored in ROM 138. RAM 140 typically contains data and/or program modules that are immediately accessible to and/or presently being operated on by processing unit 132. By way of example, and not limitation, FIG. 8 illustrates operating system 144, application programs 146, other program modules 148, and program data 150. The computer 130 may also include other removable/non-removable, volatile/nonvolatile computer storage media. For example, FIG. 8 illustrates a hard disk drive 154 that reads from or writes to non-removable, nonvolatile magnetic media. FIG. 8 also shows a magnetic disk drive 156 that reads from or writes to a removable, nonvolatile magnetic disk 158, and an optical disk drive 160 that reads from or writes to a removable, nonvolatile optical disk 162 such as a CD-ROM or other optical media. Other removable/non-removable, volatile/nonvolatile computer storage media that can be used in the exemplary operating environment include, but are not limited to, magnetic tape cassettes, flash memory cards, digital versatile disks, digital video tape, solid-state RAM, solid-state ROM, and the like. The hard disk drive 154, and magnetic disk drive 156 and optical disk drive 160 are typically connected to the system bus 136 by a non-volatile memory interface, such as interface 166. The drives or other mass storage devices and their associated computer storage media discussed above and illustrated in FIG. 8, provide storage of computer readable instructions, data structures, program modules and other data for the computer 130. In FIG. 8, for example, hard disk drive 154 is illustrated as storing operating system 170, application programs 172, other program modules 174, and program data 176. Note that these components can either be the same as or different from operating system 144, application programs 146, other program modules 148, and program data 150. Operating system 170, application programs 172, other program modules 174, and program data 176 are given different numbers here to illustrate that, at a minimum, they are different copies. A user may enter commands and information into computer 130 through input devices or user interface selection devices such as a keyboard 180 and a pointing device 182 (e.g., a mouse, trackball, pen, or touch pad). Other input devices (not shown) may include a microphone, joystick, game pad, satellite dish, scanner, or the like. These and other input devices are connected to processing unit 132 through a user input interface 184 that is coupled to system bus 136, but may be connected by other interface and bus structures, such as a parallel port, game port, or a Universal Serial Bus (USB). A monitor 188 or other type of display device is also connected to system bus 136 via an interface, such as a video interface 190. In addition to the monitor 188, computers often include other peripheral output devices (not shown) such as a printer and speakers, which may be connected through an output peripheral interface (not shown). The computer 130 may operate in a networked environment using logical connections to one or more remote computers, such as a remote computer 194. The remote computer 194 may be a personal computer, a server, a router, a network PC, a peer device or other common network node, and typically includes many or substantially all of the elements described above relative to computer 130. The logical connections depicted in FIG. 8 include a local area network (LAN) 196 and a wide area network (WAN) 198, but may also include other networks. LAN 136 and/or WAN 138 can be a wired network, a wireless network, a combination thereof, and so on. Such networking environments are commonplace in offices, enterprise-wide computer networks, intranets, and global computer networks (e.g., the Internet). When used in a local area networking environment, computer 130 is connected to the LAN 196 through a network interface or adapter 186. When used in a wide area networking environment, computer 130 typically includes a modem 178 or other means for establishing communications over the WAN 198, such as the Internet. The modem 178, which may be internal or external, is connected to system bus 136 via the user input interface 184, or other appropriate mechanism. In a networked environment, program modules depicted relative to computer 130, or portions thereof, may be stored in a remote memory storage device (not shown). By way of example, and not limitation, FIG. 8 illustrates remote application programs 192 as residing on the memory device. It will be appreciated that the network connections shown are exemplary and other means of establishing a communications link between the computers may be used. Generally, the data processors of computer 130 are programmed by means of instructions stored at different times in the various computer-readable storage media of the computer. Programs and operating systems are typically distributed, for example, on floppy disks or CD-ROMs. From there, they are installed or loaded into the secondary memory of a computer. At execution, they are loaded at least partially into the computer's primary electronic memory. The invention described herein includes these and other various types of computer-readable storage media when such media contain instructions or programs for implementing the operations described below in conjunction with a microprocessor or other data processor. For purposes of illustration, programs and other executable program components, such as the operating system, are illustrated herein as discrete blocks. It is recognized, however, that such programs and components reside at various times in different storage components of the computer, and are executed by the data processor(s) of the computer. Although described in connection with an exemplary computing system environment, including computer 130, the invention is operational with numerous other general purpose or special purpose computing system environments or configurations. The computing system environment is not intended to suggest any limitation as to the scope of use or functionality of the invention. Moreover, the computing system environment should not be interpreted as having any dependency or requirement relating to any one or combination of components illustrated in the exemplary operating environment. Examples of well known computing systems, environments, and/or configurations that may be suitable for use with the invention include, but are not limited to, personal computers, server computers, hand-held or laptop devices, multiprocessor systems, microprocessor-based systems, set top boxes, programmable consumer electronics, mobile telephones, network PCs, minicomputers, mainframe computers, distributed computing environments that include any of the above systems or devices, and the like. Those skilled in the art will note that the order of execution or performance of the methods illustrated and described herein is not essential, unless otherwise specified. That is, it is contemplated by the inventors that elements of the methods may be performed in any order, unless otherwise specified, and that the methods may include more or less elements than those disclosed herein. When introducing elements of the present invention or the embodiment(s) thereof, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained. As various changes could be made in the above products and methods without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. | <SOH> BACKGROUND OF THE INVENTION <EOH>Previous computer input devices, such as mice, include rotatable balls mounted within a housing, yet rotatably engaging a surface. As the housing of such a mouse translates across the surface, the ball rotates within the housing, engaging horizontally and vertically situated wheels that rotate against the ball, thereby indicating horizontal (e.g., side to side or x-direction) and vertical (e.g., back and forth or y-direction) movement of the mouse across the surface. When the device is lifted from the surface, hereinafter referred to as lift-off, the ball stops rotating and the horizontal and vertical movement information provided by the wheels stops. This feature is particularly useful to a user who has reached a point where the device can no longer move with respect to the tracking surface, but the user would like to continue tracking in that particular direction on screen. By lifting the device off of the tracking surface, the user can reposition the device, while the cursor remains stationary because tracking is suspended during lift-off. When tracking resumes, horizontal and vertical wheel rotation translates into an on-screen visual image of a cursor that responds to movement of the device. Because such devices have a moving ball passing through a hole in the housing, such devices often become contaminated with dust and dirt, which may yield inaccurate or intermittent cursor tracking. Moreover, the tracking surface and ball require sufficient friction between the two to cause the ball to rotate when the housing translates over the surface. To help provide such friction and minimize contamination of the device, specialized tracking surfaces (e.g., mouse pads) are typically used. Thus, a major limitation of such a device is that it requires a tracking surface with particular characteristics, such as adequate friction and cleanliness, which are not readily found on all surfaces that would otherwise be useful for tracking. Building upon these primarily mechanical tracking devices, optical tracking devices have become available. Such devices optically track movement of a surface, rather than mechanically as with the devices described immediately above. These optical tracking devices may avoid some of the drawbacks associated with the mechanical devices described above. In particular, optical devices typically do not require wheels in contact with a movable ball, which acts as a common collection point for dust and dirt. Instead, the movable ball may be covered with a distinct pattern. As the ball rotates over a surface due to movement of the input device, photodetectors facing another side of the ball collect information about the movement of the ball's distinct pattern as the ball rotates. A tracking engine then collects this information, determines which way the pattern is translating and translates a cursor on the screen similarly, as described above. Lift-off detection is performed as discussed above, when lifted the ball stops moving so the device stops tracking. These devices offer improvements over previous designs by eliminating moving parts (the wheels) and changing the ball detection interaction from mechanical to optical. However, such devices lack the ability to track on any surface, requiring a suitable frictional interface between the ball and the surface. Moreover, these devices still require one moving part, namely, the ball. In addition, aliasing artifacts may cause the cursor to skip, rather than move fluidly. Still other optical devices place a pattern on the tracking surface (e.g., a mouse pad), rather than on the rotatable ball, thereby using the mouse pad to generate optical tracking information. Although such devices are able to eliminate the moving ball, they are less universal by requiring a specific tracking surface to operate. Other more recent optical tracking devices eliminate the need for a patterned ball or mouse pad. One such device utilizes an LED to project light across the tracking surface at a grazing angle relative to the tracking surface. The mouse then collects tracking information by two methods: first, by tracking changes in color on the tracking surface by any pattern that may appear on the tracking surface; or second, by detecting dark shadows cast by high points in the surface texture, which appear as dark spots. Such an LED device eliminates the moving ball of previous devices, and is useful on a variety of surfaces. However, smooth surfaces with little color variation, such as surfaces with a fine microfinish similar to glass or clear plastic, may prove difficult to track upon. More importantly, these systems lack the ability to detect when the device has been removed from the tracking surface (lift-off) for freezing the cursor. Without freezing the cursor upon lift-off, the tracking device will continue to track when the user is attempting to reposition the device on the tracking surface while leaving the cursor in the same place. | <SOH> SUMMARY OF THE INVENTION <EOH>Accordingly, a data input device capable of generating laser light beams altered by Doppler self-mixing effects, detecting altered characteristics of the projected light beams, determining the relative distance between the data input device and the tracking surface as a function of the altered characteristic of the projected light beam is desired to address one or more of these and other disadvantages. In accordance with one aspect of the invention, a data input device for use with a tracking surface having light-scattering properties with respect to the device is disclosed. The device comprises a single laser having a cavity from which a light beam is projected. The laser is configured to project the light beam onto the tracking surface. At least a portion of the light beam striking the tracking surface reflects back into the cavity of the laser and thereby alters at least one characteristic of the projected light beam. A detector associated with the laser detects the altered characteristic of the light beam projected by the laser. A controller responsive to the detector determines the relative distance between the data input device and the tracking surface as a function of the altered characteristic of the projected light beam detected by the detector. In another aspect of the invention, a data input device for use with a tracking surface having light-scattering properties with respect to the device is disclosed. The device comprises a laser having a cavity from which a light beam is projected onto the tracking surface. The light beam is oriented substantially perpendicular to the tracking surface when the device is operating in a tracking mode. At least a portion of the light beam striking the tracking surface reflects back into the cavity of the laser substantially as set forth above. The device further comprises a detector and a controller substantially as set forth above. In yet another aspect of the invention, a method comprises projecting a light beam from a laser having a laser cavity onto a tracking surface and receiving at least a portion of the light reflected by the tracking surface within the laser cavity. The method further comprises mixing the received reflected light with light generated within the laser cavity. The mixing thereby alters at least one characteristic of the projected light beam. A light beam with the at least one altered characteristic is projected from the laser cavity. The method further comprises detecting the at least one altered characteristic of the light beam and determining the relative distance between the laser cavity and the tracking surface as a function of the at least one altered characteristic of the projected light beam. In still another aspect of the invention, a data input device for use with a tracking surface comprises a single laser and a detector generally as set forth above. The device further comprises a controller responsive to the detector for operating the device in a tracking mode or a non-tracking mode depending upon the at least one altered characteristic of the projected light beam. Alternatively, the invention may comprise various other methods and apparatuses. Other features will be in part apparent and in part pointed out hereinafter. | 20040121 | 20080129 | 20050721 | 65810.0 | 0 | LIANG, REGINA | DATA INPUT DEVICE AND METHOD FOR DETECTING LIFT-OFF FROM A TRACKING SURFACE BY LASER DOPPLER SELF-MIXING EFFECTS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,761,979 | ACCEPTED | Multiple bi-directional input/output power control system | A multiple bi-directional input/output power control system includes a network of functional blocks housed in a single enclosure, providing DC power to one or more DC loads, and providing control and internal pathways, sharing one or more AC and/or DC power inputs. The system feeds back AC power from the DC power source into an AC input connection, and the fed-back AC power is shared by other AC loads. The system operates at least one alternative source of DC in a dynamic manner, allowing maximization of power generating capability at respective specific operating conditions of the moment. | 1. In a power sharing system in a DC load environment having: a source of AC; an alternative source of DC; a power controller capable of inputting voltage regulated DC power simultaneously from said sources, said alternative source of DC making a shared contribution of power selected by said power controller, and having a power junction means for delivering a regulated voltage DC to a DC compatible load at an output of said power sharing system; said power controller controlling supply side power sharing to a DC load side; said power controller having a converter converting AC inputted electrical power into a defined DC-regulated voltage to provide and manage power to said DC compatible load; said power controller producing voltage regulated power by controlling response of said alternative source of DC power; said power controller capable of altering the output voltage of said power junction means for directing power from said secondary sources of DC power to limit peak power supplied from said source of AC power to said DC compatible load in accordance with a pre-set threshold of power from said source of AC power in order to minimize peak power surcharges; wherein the improvement comprises: means for operating said alternative source of DC in a dynamic manner that allows the utilization of all the power generating capability at the specific operating conditions of the moment; and, means for delivering power from said alternative primary power source of DC in excess of that required by said DC compatible load back to said source of AC. 2. The power system of claim 1 wherein said DC compatible load is selected from the group consisting of: a lighting system, a DC power consumption device; a lighting ballast; a lamp; solid state lighting; a DC motor; an AC motor with variable frequency drive (VFD); and/or an inverter. 3. The power system of claim 1 further comprising an external DC source being is an energy storage device. 4. The power system of claim 1 wherein said alternative source of DC is at least one of a photo voltaic energy source, a cogenerator, a wind energy conversion system and/or a fuel cell. 5. The power system of claim 1 wherein said source of AC is at least one of a utility AC grid; a generator and/or a stand alone inverter with a connected DC source. 6. The power system as in claim 3 in which said power controller contains circuitry for combining power from said alternative source of DC and said external DC energy storage device, in the absence of power from said source of AC. 7. The power sharing system as in claim 6 further comprising a means to stop delivering of said DC to said AC source when said source of AC power is off and not present. 8. A power sharing system in a DC load environment including: a source of AC; an alternative source of DC; said power sharing system comprising: a bi-directional isolated power supply for converting power from said source of AC to DC power; means for operating said alternative source of DC in a dynamic manner that allows the utilization of all the power generating capability at the specific operating conditions of the moment of said alternative source of DC; a DC compatible load; a converter for transforming the output of said alternative source of DC to a voltage level suitable for use by said DC compatible load; a metering module for receiving data relating to power from said converter; providing data to a digital processor to control said bi-directional isolated power supply, to provide power for supplementing power insufficiency delivered by said converter, thereby supplying load requirements of said DC compatible load, and, said power system module including means for feeding back to said source of AC, through said bi-directional isolated power supply, power delivered by said converter, in excess of that required by said DC compatible load at any given time. 9. The power system of claim 8 wherein said DC compatible load is selected from the group consisting of: a lighting system; a DC power consumption device; a lighting ballast; a lamp; solid state lighting; a DC motor; an AC motor with variable frequency drive (VFD); and/or an inverter. 10. The power system of claim 8 further comprising an external DC energy storage device. 11. The power sharing system of claim 8 in which said alternative source of DC is at least one of a photovoltaic energy source, a wind energy conversion system, a cogenerator and/or a fuel cell. 12. The power system of claim 8 wherein said source of AC is at least one of a utility AC grid; a generator and/or a stand alone inverter with a connected DC source. 13. The power sharing system of claim 8 having a battery backup system to supply DC power to said DC compatible load when there is a failure in said source of AC and said alternative source of DC produces insufficient power for said DC compatible load; said system having a means for feeding back AC power from said external DC energy storage device into an AC input connection. 14. The power sharing system as in claim 8 further comprising a means to prevent feeding back of said AC, when said source of AC power is turned off. 15. A multiple bi-directional input/output power control system comprising: at least one power control unit having a network of functional blocks housed in a single enclosure, said unit providing DC power to at least one DC load, said unit providing control and internal pathways sharing a plurality of power inputs, said inputs including: an AC power source, at least one alternative DC power source, and, said unit having a means for feeding back AC power from said at least one DC power source into an AC input connection. 16. The multiple bi-directional input/output power control system as in claim 15 further comprising at least one external DC energy storage device. 17. The multiple bi-directional input/output power control system as in claim 15 wherein said at least one power control unit is a plurality of interconnected power control units. 18. The multiple bi-directional input/output power control system as in claim 15 where said functional blocks are selected from the group consisting of: at least one hard wired electronic circuit board; software running on an internal digital processor, and/or as a combination thereof. 19. The multiple bi-directional input/output power control system as in claim 15 wherein said network of functional blocks includes a digital processor, a low voltage ON/OFF control block, an alternate DC source DC/DC converter, a DC isolation block, and a bi-directional AC/DC power supply with a bi-directional control module, power factor correction means, an anti-islanding control block, and metering network including metering control module wherein: said digital processor controls said functional blocks and gathers data from said metering network and metering control module; said alternate DC source DC/DC converter conditions output of connected alternate source to match power requirements of said DC load; said low voltage on/off control block permits direct external control of said DC isolation and said alternate DC source DC/DC converter; and, said bi-directional AC/DC power supply providing connection to said source of AC for at least one of the following functions: to provide power, with said power factor correction means to said DC connected load, and/or to feed back AC power as directed by said bi-directional control module, with conditioning intervention by said power factor correction means, and safety interlock control by said anti-islanding control block. 20. The multiple bi-directional input/out power control system as in claim 16 wherein said at least one power control unit operates said alternative DC power source in conjunction with said AC source of power and/or said external DC energy storage device, in a dynamic manner allowing maximum power generating capability of said alternative DC power source at specific operating conditions of the moment. 21. The multiple bi-directional input/output power control unit as in claim 19 wherein said power control unit delivers power, in excess of that required by said at least one compatible load, to said AC power source, said external DC energy storage device, and/or a combination thereof both in a shared manner. 22. The multiple bi-directional input/output power control unit as in claim 15 wherein said means for feeding back AC power comprises a bi-directional microprocessor-controlled power supply. 23. The multiple bi-directional input/output power control unit as in claim 19 wherein said DC-to-DC Converter is a buck/boost converter with dynamic voltage controls. 24. The multiple bi-directional input/output power control unit as in claim 15 further comprising a DC-based meter, said meter monitoring at least one of: AC input/output, DC input/output, and/or, internal voltages and currents. 25. The multiple bi-directional input/output power control unit as in claim 19 wherein said bi-directional AC/DC power supply includes an AC/DC converter receiving at least one signal from said digital processor, and performing at least one function of the following functions: 1) rectifying AC and providing regulated DC voltage via DC isolation when required by said at least one DC load and/or said alternate DC power source; 2) rectifying AC and providing regulated DC voltage to said external DC energy storage device; and, 3) inverting DC power from said alternate DC power source or said external DC energy storage device and sending said DC power back to said AC power source. 26. The multiple bi-directional input/output power control system as in claim 19 wherein said power factor correction means adjusts a power factor of said power control unit to a pre-determined specified value. 27. The multiple bi-directional input/output power control system as in claim 19 wherein said anti-islanding means includes an analog and/or digital logic circuit detecting loss of connection to said AC power source grid and/or external synchronization source. 28. The multiple bi-directional input/output power control system as in claim 19 wherein said bi-directional control module includes an analog and/or digital logic device enabling said bi-directional power supply to invert DC power. 29. The multiple bi-directional input/output power control system as in claim 19 wherein said DC isolation block means electrically isolates DC output from said AC power source. 30. The multiple bi-directional input/output power control system as in claim 15 wherein said at least one DC load is selected from the group consisting of: a lighting system; a DC power consumption device; a lighting ballast; a lamp; solid state lighting; a DC motor; an AC motor with variable frequency drive (VFD); and/or an inverter. 31. The multiple bi-directional input/output power control system as in claim 19 wherein said low voltage ON/OFF control shuts down all output circuits via at least one of a low voltage signal and/or a wireless communication device. 32. The multiple bi-directional input/output power control system as in claim 19 wherein said low voltage ON/OFF control includes at least one variable signal dynamically controlling voltage of said output circuits. 33. The multiple bi-directional input/output power control system as in claim 19 wherein said alternate DC source DC/DC converter converts output of an alternate energy source to a voltage level suitable for said at least one DC load, said converter dynamically changing operating characteristics of said alternative energy source, permitting optimization of power transfer and/or permitting interface with said alternative DC energy source. 34. The multiple bi-directional input/output power control system as in claim 15 wherein said alternative DC energy source is at least one of: a photovoltaic (PV) device, a wind turbine, a fuel cell, and/or an engine driven cogeneration device. 35. The multiple bi-directional input/output power control system as in claim 16 wherein said external energy storage device stores DC power and supplies power to said at least one DC load and/or alternate energy source. 36. The multiple bi-directional input/output power control system as in claim 19 wherein said digital processor monitors and controls power delivery to and from a plurality of power sources and loads, said digital processor providing an interface for providing data and receiving control signals from an external central data acquisition and control unit. 37. The multiple bi-directional input/output power control system as in claim 19 wherein said digital processor provides at least one of: 1) dynamic voltage control and/or current control supplied by an alternate DC Source; 2) an ON/OFF control of all output circuits; 3) an ON/OFF control for the bi-directional AC/DC power Supply; 4) dynamically change output voltage; and 5) dynamically change voltage of the DC link. 38. The multiple bi-directional input/output power control system as in claim 19 wherein said digital processor controls providing at least one of: 1) volts, amps, and/or power delivered/supplied by the bi-directional AC/DC power supply; 2) volts, amps, and/or power delivered/supplied by the alternate DC source; 3) volts, amps, and/or power delivered/supplied by the external energy storage device; 4) volts, amps, and/or power delivered/supplied by the load; and/or; 5) system status, alarms and/or operating mode status. 39. The multiple bi-directional input/output power control system as in claim 36 wherein said central data acquisition and control unit provides central control and data collection of data from said multiple power units, via each respective digital processor. 40. The multiple bi-directional input/output power control system as in claim 19 wherein said bi-directional power supply is transformer isolated and includes a bridge topology permitting its operation as both a synchronous rectifier for supplying DC power and an inverter supplying AC power at its input from DC sources. 41. The multiple bi-directional input/output power control system as in claim 40 wherein said bridge topology includes at least one of: a MOFSET switch and/or an insulated gate bipolar transistor (IGBT). 42. The multiple bi-directional input/output power control system as in claim 39 wherein said central data acquisition and control unit includes an enterprise level digital processor monitoring and controlling operation from a central location, soliciting sensor information from each power control unit, said central data acquisition and control unit monitoring loading of said AC utility power source line to said enterprise, controlling each said power control unit to limit the peak utility power used, by adaptively sharing power available with requirements of said at least one DC load, thereby reducing peak surcharges. 43. A multiple bi-directional input/output power control system comprising a network of functional blocks housed in a single enclosure, said system providing DC power to at least one DC load, said system providing control and internal pathways sharing at least one of a plurality of AC and/or DC power inputs, said system feeding back AC power from said at least one DC power source into an AC input connection, said fed-back AC power shared by other AC loads, said system operating at least one alternative source of DC in a dynamic manner allowing maximization of power generating capability at respective specific operating conditions of the moment. | FIELD OF THE INVENTION The present invention relates to electrical power units for use in sharing and connecting AC alternating current and DC direct current electrical power supplies. SUMMARY OF THE INVENTION The Multi-Function Power Control Unit (MFPCU) of this invention is a network of functional blocks housed in a single enclosure to provide DC power to one or more DC loads. It provides control and internal pathways to share or select a variety of power inputs including AC utility power, alternative DC power sources, as well as DC power from external energy storage devices. Additionally, the MFPCU can also feed back AC power from other attached DC sources into the AC input connection to be shared by other AC loads (including other MFPCU's) within the enterprise. The functional blocks are implemented as hard wired electronic circuit boards, as software running on an internal digital processor, or as a combination of both types using state-of-the-art design techniques. The multi-function power control unit includes the following functional blocks within its enclosure: a digital processor, a low voltage ON/OFF control block, an alternate DC source DC/DC converter, a DC isolation block, and a bi-directional AC/DC power supply with a bi-directional control module, power factor correction means, and an anti-islanding control block. In addition, the MFPCU has connectors for the following: AC input, DC load, external energy storage device, alternate DC power source, external control device, and central data acquisition and control. The AC input is typically designed for single phase 208-277 VAC at 50 or 60 Hz. Alternatively, the AC input can be designed for three phase 208-480 VAC at 50 or 60 Hz. The multi-function power control unit operates an alternative source of DC direct current, in conjunction with an AC source of power or DC power storage device, in a dynamic manner that allows maximum power generating capability of the alternative source of DC direct current at the specific operating conditions of the moment. It also can deliver power in excess of that required by a DC compatible load to the AC source of power, DC power storage device, or both in a shared manner. The system includes three major subsystems: a Bi-directional Microprocessor-Controlled 4.5 kW AC to DC Power Supply; a Buck/Boost DC-to-DC Converter with dynamic voltage control; and, a DC-Based Meter Monitoring of the AC I/O, DC I/O, and internal voltages and currents, which is based on a unique Metering and Control Module (MCM). The aforementioned bi-directional AC/DC power supply of the present invention includes an AC/DC converter that performs three functions based upon signal from Digital Processor, including the following: 1) rectifies AC and provides regulated DC voltage (via DC isolation) when required by the load or Alternate DC source; 2) rectifies AC and provides regulated DC voltage to an external energy storage device; and, 3) inverts DC power from the alternate DC source or external energy storage and sends it back to the AC System. A power factor correction means adjusts the power factor of the unit to a specified value. An anti-islanding means including analog and/or digital logic circuits is used to detect loss of connection to utility grid or external synchronization source. A bi-directional control module includes an analog and/or digital logic device that enables the bi-directional power supply to “invert” DC power. If this module is not installed the unit can only provide the above noted functions “1” and “2” but cannot provide function “3”. A DC isolation means electrically isolates DC output from AC input. The bi-directional power supply powers a DC Load with High Voltage (250-400 Volts). The Direct Current (DC) load is a device that consumes power, such as a lighting ballast; lamp; solid state lighting, such as a light emitting diode (LED); a DC motor; an AC motor with variable frequency drive (VFD); or an Inverter. The load may feed power backwards for short durations, such as during braking of a motor. A low voltage ON/OFF control shuts down all output circuits via a low voltage signal or via wireless communication device. However, another variation allows for a variable signal to dynamically control the voltage of the output circuits. An alternate DC source DC/DC converter converts output of an alternate energy source to a voltage level suitable for the DC load. This converter has the ability to dynamically change the operating characteristics of an alternative energy source to permit optimization of power transfer or for proper interface with an alternative energy source, such as a photovoltaic (PV) device, a wind turbine, a fuel cell, or an engine driven cogeneration device. In another variation, the converter is used to provide DC power back to the alternative energy source during periods of inactivity. For example, a wind turbine needs to maintain its direction into the wind, and yaw motors operate during periods of low wind before power production is achievable. Another example is the start-up of a fuel cell or cogeneration system, which may require fuel pumps, cooling pumps or other auxiliary equipment to be running before power production is achievable. An external energy storage device stores DC power for use in supplying power to the DC load and/or alternate energy source, in the event of a loss of AC power, supplementing power to DC load when required, or supplementing power to AC system. Examples include a high voltage battery, a low voltage battery with DC/DC converter, a flow Battery, a flywheel, and a capacitor. A digital processor monitors and controls power delivery to and from all sources and loads. The digital processor provides an interface for providing data and receiving control signals from the external central data acquisition and control unit. It may provide the following controls: 1) dynamic voltage control and/or current control supplied by an alternate DC Source; 2) an ON/OFF control of all output circuits; 3) an ON/OFF control for the bi-directional AC/DC power Supply; 4) dynamically change output voltage; and 5) dynamically change voltage of the DC link. The digital processor also supplies the following data, if requested or required by the external central data acquisition and control unit: 1) volts, amps, and/or power delivered/supplied by the bi-directional AC/DC power supply; 2) volts, amps, and/or power delivered/supplied by the alternate DC source; 3) volts, amps, and/or power delivered/supplied by the external energy storage device; 4) volts, amps, and/or power delivered/supplied by the load; and, 5) system status, alarms, operating mode (i.e.: start-up, run, power failure, shutdown, fault, etc.) The central data acquisition and control unit is used to provide the ability for central control and data collection of multiple power units, via their digital processors. It may be used for enterprise level and/or multi-building control, such as load management of utility feeder servicing multiple buildings. The performance of the multi-function power control system of this invention for supplying a high efficiency lighting system is as follows: At this time, AC input high efficiency T-8 lighting ballasts operate an overall efficiency of 88%. A high voltage DC ballast is expected to operate at 94% efficiency. The multi-function power control system unit is expected to achieve a throughput efficiency of 96%. Thus, when combined, the overall efficiency can be 90%, which is 2% better than current systems. The main reason for the increase is due to the larger scale AC/DC power supply. This is analogous to central power plants with a distribution system being more efficient than the equivalent sum of multiple smaller scale power plants. A larger scale system is also proposed. The current design is for a power unit that is sized to meet the requirements of a single phase 277 V lighting circuit (up to 4.5 kW). An upgrade is a three phase unit capable of supplying multiple lighting circuits, via a DC distribution system, and a single interconnection to the AC system. The larger scale system can be from 15 to 250 kW. BRIEF DESCRIPTION OF THE DRAWINGS The present invention can best be understood in connection with the accompanying drawings. It is noted that the invention is not limited to the precise embodiments shown in drawings, in which: FIG. 1 is a Block diagram of a multi-function power control unit (MFPCU) of this invention with external attachment blocks. FIG. 2 is a chart of IV curves for typical solar cells showing maximum power load line. FIG. 3 is a Block diagram showing main current flow through the MFPCU for an AC Sourced High Efficiency Lighting mode. FIG. 4 is a Block diagram showing main current flow through the MFPCU for an AC Outage Operation mode. FIG. 5 is a Block diagram of enterprise with multiple MFPCU's in a Peak Shaving Enterprise AC Wheeling mode. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows a block diagram of MFPCU 1 with a network of various functional blocks within and connections to other functional blocks at its periphery. bi-directional AC/DC Power Supply 2 is transformer isolated and has a bridge topology which incorporates MOSFETS or preferably IGBT's (insulated gate bipolar transistors) which permit operation as both a synchronous rectifier for supplying DC as well as an inverter to supply AC at its input from DC sources. bi-directional Control Module 3 controls the operation as to direction, while Power Factor Control Means 4 insures that power factor at the AC input remains essentially at unity. The Anti-Islanding Means 5 detects loss of AC utility power and blocks the feedback of AC power at the connection 15 from DC sources. Power supply 2 is controlled by Digital Processor 6. Low Voltage ON/OFF control 7 receives signals (such as emergency situations) from external control devices 13 via line 18 to shut down Alternate DC Source DC/DC Converter 9 or DC Isolation block 8. Alternate DC Sources 14 such as photovoltaic, wind turbines, fuel cells, etc. are connected via line 19. The connection is shown as bi-directional since the alternate DC sources may require power in some off modes such as for yaw motors for wind turbines or pumps which are required at start-up of fuel cells. DC Load 11 is connected via line 21 which is also shown as bi-directional wherein, on some occasions, DC loads can generate power. One example is a DC motor after shutdown which can act as a generator for a brief period. External energy storage device 10 stores DC power for use in supplying power to the DC load and/or alternate energy source, in the event of a loss of AC power, supplementing power to DC load when required, or supplementing power to AC system. Examples include a high voltage battery, a low voltage battery with DC/DC converter, a flow Battery, a flywheel, and a capacitor. External Energy Device 10 is connected via line 22. This connection is also bi-directional since a variety of energy storage devices require power during the charging phase. Simple chemical storage batteries such as lead acid or NiMH require periodic charging. Flow batteries require the use of circulation pumps in the charging process, and the motor/generator of a flywheel storage device is used as a motor to “charge” or spin-up the flywheel. FIG. 1 also shows metering control module (MCM) 23, which contains various current and voltage sensors sampling the various sources and load points. These are all connected in a metering network, including metering control module 23, to digital processor 6. Central Data Acquisition and Control Unit 12 is an enterprise level digital processor which monitors and controls the operation from a central location. Besides soliciting sensor information from all MFPCU's, unit 12 also monitors the loading of the utility feeder line to the enterprise; in this way it can be used to control the .MFPCU's to limit the peak utility power used by adaptively sharing the power available with load requirements thereby reducing peak surcharges. FIG. 2 shows typical current/voltage curves for solar cells at different levels of incident irradiation (here ranging from 82 to 140 W/cm squared). The load line for maximum power collected is also drawn. The state-of-the-art control for extracting the maximum output from a solar array over varying operating conditions is known as maximum power point tracking or MPPT. This is achieved either by a predictive open-loop or by a closed-loop control system. In the MFPCU of this invention, MPPT is implemented by the buck/boost DC/DC converter of block 9 under control of digital processor 6. Solar panels used with the current MFPCU generate from 250 to 600 volts. The operating voltage of a lighting load is 380VDC+/−1%. Thus alternate DC source DC/DC converter 9 will maintain this output while the input varies from 250 to 600 VDC; this is done in conjunction with MPPT protocols to maximize power transfer over dynamically changing conditions such as incident radiation and ambient temperature. FIGS. 3-5 illustrate the main power flows through MFPCU blocks and paths for different modes of operation. FIG. 3 shows the most typical mode of operation for an MFPCU. It illustrates AC sourced high efficiency lighting wherein load 11 is a fluorescent light load using DC-input ballasts. Utility AC power at 15 feeds into bi-directional AC/DC power supply 2 where it is converted (at unity power factor via power factor correction 4) to DC which flows toward DC isolation block 8 (via line 16) and onward to DC lighting load 11. In FIG. 3, no external storage device or alternate DC source are shown; they may simply not be implemented at this MFPCU, or they may just not be contributing power at this time. FIG. 4 shows operation during a utility power outage. Power to supply DC load 11 is supplied via line 21 by alternate DC source 14 via line 19 through DC/DC converter 9 and by external storage device 10 via lines 22 and 16 through DC isolation block 8. Note that bi-directional power supply 2 is not involved in this operation since it is shut down by anti-islanding means 5. FIG. 5 shows a multi-MFPCU enterprise operating so as to reduce power demand from utility feeder 43 entering distribution panel 44. Central data block 12 is sampling demand via line 45. Via network of bi-directional data lines 17, it can keep track of the status of each MFPCU. The distribution of utility power to each MFPCU is shown as a single line 46 (for simplicity) although multiple branch lines would probably be used. In this example, DC load 42 has heavy demand from MFPCU 32. MFPCU 31 has its load shut down, but its storage device 41 has some capacity. MFPCU 30 is supplying its own load 11, but its storage device 10 has some capacity, and currently its alternate DC source 14 has capacity in excess of load 11 demand. Central data block 12 is aware of the status of each MFPCU and the impending peak utility demand threshold, therefore a “peak shaving” protocol is automatically entered. The bi-directional power supplies 2 of MFPCU's 30 and 31 are placed in inverter mode to feed back AC derived from DC sources via lines 47 and 48 respectively. This AC is combined with utility AC on branch lines 46 to supply heavy load 42 attached to MFPCU 32 via line 49. Note that bi-directional power supply 2 in MFPCU 32 remains in rectifier mode. Obviously there are an almost infinite number of similar scenarios that are possible on a second by second basis; this just illustrates a possible snapshot where AC is wheeled within the enterprise from one MFPCU to another. In the foregoing description, certain terms and visual depictions are used to illustrate the preferred embodiment. However, no unnecessary limitations are to be construed by the terms used or illustrations depicted, beyond what is shown in the prior art, since the terms and illustrations are exemplary only, and are not meant to limit the scope of the present invention. It is further known that other modifications may be made to the present invention, without departing the scope of the invention, as noted in the appended Claims. | <SOH> FIELD OF THE INVENTION <EOH>The present invention relates to electrical power units for use in sharing and connecting AC alternating current and DC direct current electrical power supplies. | <SOH> SUMMARY OF THE INVENTION <EOH>The Multi-Function Power Control Unit (MFPCU) of this invention is a network of functional blocks housed in a single enclosure to provide DC power to one or more DC loads. It provides control and internal pathways to share or select a variety of power inputs including AC utility power, alternative DC power sources, as well as DC power from external energy storage devices. Additionally, the MFPCU can also feed back AC power from other attached DC sources into the AC input connection to be shared by other AC loads (including other MFPCU's) within the enterprise. The functional blocks are implemented as hard wired electronic circuit boards, as software running on an internal digital processor, or as a combination of both types using state-of-the-art design techniques. The multi-function power control unit includes the following functional blocks within its enclosure: a digital processor, a low voltage ON/OFF control block, an alternate DC source DC/DC converter, a DC isolation block, and a bi-directional AC/DC power supply with a bi-directional control module, power factor correction means, and an anti-islanding control block. In addition, the MFPCU has connectors for the following: AC input, DC load, external energy storage device, alternate DC power source, external control device, and central data acquisition and control. The AC input is typically designed for single phase 208-277 VAC at 50 or 60 Hz. Alternatively, the AC input can be designed for three phase 208-480 VAC at 50 or 60 Hz. The multi-function power control unit operates an alternative source of DC direct current, in conjunction with an AC source of power or DC power storage device, in a dynamic manner that allows maximum power generating capability of the alternative source of DC direct current at the specific operating conditions of the moment. It also can deliver power in excess of that required by a DC compatible load to the AC source of power, DC power storage device, or both in a shared manner. The system includes three major subsystems: a Bi-directional Microprocessor-Controlled 4.5 kW AC to DC Power Supply; a Buck/Boost DC-to-DC Converter with dynamic voltage control; and, a DC-Based Meter Monitoring of the AC I/O, DC I/O, and internal voltages and currents, which is based on a unique Metering and Control Module (MCM). The aforementioned bi-directional AC/DC power supply of the present invention includes an AC/DC converter that performs three functions based upon signal from Digital Processor, including the following: 1) rectifies AC and provides regulated DC voltage (via DC isolation) when required by the load or Alternate DC source; 2) rectifies AC and provides regulated DC voltage to an external energy storage device; and, 3) inverts DC power from the alternate DC source or external energy storage and sends it back to the AC System. A power factor correction means adjusts the power factor of the unit to a specified value. An anti-islanding means including analog and/or digital logic circuits is used to detect loss of connection to utility grid or external synchronization source. A bi-directional control module includes an analog and/or digital logic device that enables the bi-directional power supply to “invert” DC power. If this module is not installed the unit can only provide the above noted functions “1” and “2” but cannot provide function “3”. A DC isolation means electrically isolates DC output from AC input. The bi-directional power supply powers a DC Load with High Voltage (250-400 Volts). The Direct Current (DC) load is a device that consumes power, such as a lighting ballast; lamp; solid state lighting, such as a light emitting diode (LED); a DC motor; an AC motor with variable frequency drive (VFD); or an Inverter. The load may feed power backwards for short durations, such as during braking of a motor. A low voltage ON/OFF control shuts down all output circuits via a low voltage signal or via wireless communication device. However, another variation allows for a variable signal to dynamically control the voltage of the output circuits. An alternate DC source DC/DC converter converts output of an alternate energy source to a voltage level suitable for the DC load. This converter has the ability to dynamically change the operating characteristics of an alternative energy source to permit optimization of power transfer or for proper interface with an alternative energy source, such as a photovoltaic (PV) device, a wind turbine, a fuel cell, or an engine driven cogeneration device. In another variation, the converter is used to provide DC power back to the alternative energy source during periods of inactivity. For example, a wind turbine needs to maintain its direction into the wind, and yaw motors operate during periods of low wind before power production is achievable. Another example is the start-up of a fuel cell or cogeneration system, which may require fuel pumps, cooling pumps or other auxiliary equipment to be running before power production is achievable. An external energy storage device stores DC power for use in supplying power to the DC load and/or alternate energy source, in the event of a loss of AC power, supplementing power to DC load when required, or supplementing power to AC system. Examples include a high voltage battery, a low voltage battery with DC/DC converter, a flow Battery, a flywheel, and a capacitor. A digital processor monitors and controls power delivery to and from all sources and loads. The digital processor provides an interface for providing data and receiving control signals from the external central data acquisition and control unit. It may provide the following controls: 1) dynamic voltage control and/or current control supplied by an alternate DC Source; 2) an ON/OFF control of all output circuits; 3) an ON/OFF control for the bi-directional AC/DC power Supply; 4) dynamically change output voltage; and 5) dynamically change voltage of the DC link. The digital processor also supplies the following data, if requested or required by the external central data acquisition and control unit: 1) volts, amps, and/or power delivered/supplied by the bi-directional AC/DC power supply; 2) volts, amps, and/or power delivered/supplied by the alternate DC source; 3) volts, amps, and/or power delivered/supplied by the external energy storage device; 4) volts, amps, and/or power delivered/supplied by the load; and, 5) system status, alarms, operating mode (i.e.: start-up, run, power failure, shutdown, fault, etc.) The central data acquisition and control unit is used to provide the ability for central control and data collection of multiple power units, via their digital processors. It may be used for enterprise level and/or multi-building control, such as load management of utility feeder servicing multiple buildings. The performance of the multi-function power control system of this invention for supplying a high efficiency lighting system is as follows: At this time, AC input high efficiency T-8 lighting ballasts operate an overall efficiency of 88%. A high voltage DC ballast is expected to operate at 94% efficiency. The multi-function power control system unit is expected to achieve a throughput efficiency of 96%. Thus, when combined, the overall efficiency can be 90%, which is 2% better than current systems. The main reason for the increase is due to the larger scale AC/DC power supply. This is analogous to central power plants with a distribution system being more efficient than the equivalent sum of multiple smaller scale power plants. A larger scale system is also proposed. The current design is for a power unit that is sized to meet the requirements of a single phase 277 V lighting circuit (up to 4.5 kW). An upgrade is a three phase unit capable of supplying multiple lighting circuits, via a DC distribution system, and a single interconnection to the AC system. The larger scale system can be from 15 to 250 kW. | 20040121 | 20070605 | 20050728 | 76625.0 | 1 | KAPLAN, HAL IRA | MULTIPLE BI-DIRECTIONAL INPUT/OUTPUT POWER CONTROL SYSTEM | SMALL | 0 | ACCEPTED | 2,004 |
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10,762,095 | ACCEPTED | APPARATUS FOR REMOVING AIR AND/OR DEBRIS FROM A FLOW OF LIQUID | Abstract of the Disclosure An apparatus removes air or debris from a flow of liquid. The apparatus includes a shell having an inlet, an outlet, and an elongate inner cavity in fluid communication with each of the inlet and the outlet. A plurality of elongate coalescing medium assemblies are disposed within the cavity of the shell such that the coalescing medium assemblies are oriented substantially parallel to each other. Each coalescing medium assembly includes a plurality of wire mesh tubes oriented substantially parallel to each other. A wire mesh retaining wall substantially surrounds the tubes and holds the tubes together. | 1. An apparatus for removing air or debris from a flow of liquid, said apparatus comprising: a shell having an inlet, an outlet, and an elongate inner cavity in fluid communication with each of said inlet and said outlet; and a plurality of elongate coalescing medium assemblies disposed within said cavity of said shell such that said coalescing medium assemblies are oriented substantially parallel to each other, each said coalescing medium assembly including: a plurality of wire mesh tubes oriented substantially parallel to each other; and a wire mesh retaining wall substantially surrounding said tubes and holding said tubes together. 2. The apparatus of Claim 1 wherein each said coalescing medium assembly includes a band wrapped around said retaining wall and holding said retaining wall in engagement with said tubes. 3. The apparatus of Claim 1 wherein each said coalescing medium assembly includes an elongate core element substantially surrounded by said tubes and oriented substantially parallel to said tubes, said core element having: a longitudinal axis extending in a longitudinal direction; and at least one substantially continuous side surface facing in a lateral direction substantially perpendicular to the longitudinal direction. 4. Canceled. 5. The apparatus of Claim 3 further comprising an end cap including a plurality of recesses, an end of each of said core elements being received in a respective one of said recesses. 6. The apparatus of Claim 1 wherein said inlet and said outlet are disposed at locations along a longitudinal direction that are between opposite ends of said coalescing medium assemblies. 7. A coalescing medium assembly for removing air or debris from a flow of liquid, said coalescing medium assembly comprising: a plurality of wire mesh tubes oriented substantially parallel to each other; and a wire mesh retaining wall substantially surrounding said tubes and holding said tubes together. 8. The assembly of Claim 7 wherein said coalescing medium assembly includes a band wrapped around said retaining wall and holding said retaining wall in engagement with said tubes. 9. The assembly of Claim 7 wherein each of said wire mesh tubes has an outer diameter approximately between 0.4 inch and 0.8 inch. 10. The assembly of Claim 7 wherein said wire mesh tubes and said wire mesh retaining wall are formed of wire having a thickness of approximately between 0.02 inch and 0.04 inch. 11. The assembly of Claim 7 wherein at least one of said wire mesh tubes includes a projection extending from an inner surface of said tube and into an interior of said tube. 12. The assembly of Claim 7 wherein at least one of said wire mesh tubes includes an elongate surface area-providing element disposed within an interior of said tube. 13. The assembly of Claim 7 further comprising an elongate core element substantially surrounded by said tubes and oriented substantially parallel to said tubes, said core element having: a longitudinal axis extending in a longitudinal direction; and at least one substantially continuous side surface facing in a lateral direction substantially perpendicular to the longitudinal direction. 14. The assembly of Claim 13 wherein said core element comprises a cylindrical tube. 15. A coalescing medium assembly for removing air or debris from a flow of liquid, said coalescing medium assembly comprising: an elongate core element having: a longitudinal axis extending in a longitudinal direction; and at least one substantially continuous side surface facing in a lateral direction substantially perpendicular to the longitudinal direction; and a plurality of wire mesh tubes surrounding said core element and oriented substantially parallel to said core element. 16. The assembly of Claim 15 wherein each of said wire mesh tubes and said elongate core element has a substantially equal width. 17. The assembly of Claim 15 wherein each of said wire mesh tubes and said elongate core element are formed of stainless steel. 18. The assembly of Claim 15 wherein said wire mesh tubes are arranged in a substantially circular pattern when viewed in the longitudinal direction such that each said wire mesh tube engages two adjacent ones of said wire mesh tubes. 19. The assembly of Claim 18 wherein said elongate core element engages each of said wire mesh tubes arranged in a substantially circular pattern. 20. The assembly of Claim 15 wherein said elongate core element comprises a cylindrical tube. 21. (New) An apparatus for removing air or debris from a flow of liquid, said apparatus comprising: a shell having an inlet, an outlet, and an elongate inner cavity in fluid communication with each of said inlet and said outlet; and a plurality of tubes tightly packed within said cavity of said shell such that said tubes are oriented substantially parallel to each other, at least one of said tubes having a discontinuous surface. | Detailed Description of the Invention The present invention relates to an apparatus for removing air and/or debris from a flow of liquid, and, more particularly, to an apparatus including a coalescing medium for removing air and/or debris from a flow of water. It is known to use a filter to remove air and/or dirt from a flow of water. Such flows of water are commonly used in conjunction with pressure booster systems, heat exchangers, pumps, and water heaters, for example. Dirt or debris is caught or removed from the flow by the filter, and the dirt then falls to the bottom of the filter's housing. Small air bubbles form on the filter and then coalesce into larger bubbles that float to the top of the filter's housing. Previously known coalescing media/filters include a solid cylindrical copper core disposed concentrically within a cylindrical metal wire mesh. The mesh includes a continuous, substantially horizontal metal wire that is spiraled around the core and supported by substantially vertical wire segments that are evenly spaced in the horizontal direction. An array of copper wires extends radially from an outer surface of the core to thereby interconnect the core and the mesh. The opposite ends of each copper wire are respectively attached to the core and to the mesh such as by soldering. A problem is that these prior art coalescing medium/filters are difficult to manufacture. The steps of forming the metal wire spiral, soldering the vertical wire segments to the metal wire spiral to form a wire mesh, and soldering the copper wires to the solid cylindrical copper core and to the wire mesh are all labor intensive, time consuming, and costly. Another problem is that, although copper is relatively easy to solder, copper corrodes in a flow of water and is structurally weak. Thus, copper is not extremely durable for water filtering applications, and filters that include copper may need to be periodically replaced. Another disadvantage of copper is that it is a relatively expensive metal. What is needed in the art is an apparatus for removing air or debris from a flow of liquid wherein the apparatus includes a coalescing medium that can be easily and inexpensively manufactured. What is further needed in the art is an apparatus for removing air or debris from a flow of liquid wherein the apparatus is durable and does not need to be frequently replaced. The present invention provides an apparatus for removing air or debris from a flow of water wherein the apparatus includes a coalescing medium assembly formed of tubes that are easily rolled from a stainless steel wire mesh. The wire mesh tubes are arranged around a central solid cylindrical tube, and the wire mesh tubes are held against the solid cylindrical tube by a stainless steel wire mesh retaining wall that is wrapped around the tubes. Thus, the present invention provides an air/dirt removing apparatus that is easily and inexpensively manufactured and that can be formed of highly durable stainless steel. The present invention provides a coalescing medium assembly that can be easily, quickly and inexpensively manufactured by rolling pieces of wire mesh into tubular or tube-like shapes, and arranging the "tubes" such that liquid flows through the tubes in a direction substantially perpendicular to the lengths of the tubes. The tubes can be placed in the cylindrical cavity of a shell that is in fluid communication with liquid-carrying conduits. A cylindrical tube having a substantially continuous side surface can be centrally positioned among the wire mesh tubes. The central tubes can functionally complement the wire mesh tubes in that the substantially continuous side surface of the central tube can primarily promote the coalescing of air bubbles, while the wire mesh tubes can primarily catch, trap or otherwise remove dirt particles from the flow of liquid. The wire mesh tube can also provide some additional surface area for coalescing. With or without a central tube, the wire mesh tubes can be easily held together by a wire mesh retaining wall that can perform the same filtering and coalescing functions as the wire mesh tubes themselves. The invention comprises, in one form thereof, an apparatus removes air or debris from a flow of liquid. The apparatus includes a shell having an inlet, an outlet, and an elongate inner cavity in fluid communication with each of the inlet and the outlet. A plurality of elongate coalescing medium assemblies are disposed within the cavity of the shell such that the coalescing medium assemblies are oriented substantially parallel to each other. Each coalescing medium assembly includes a plurality of wire mesh tubes oriented substantially parallel to each other. A wire mesh retaining wall substantially surrounds the tubes and holds the tubes together. The invention comprises, in another form thereof, a coalescing medium assembly for removing air or debris from a flow of liquid. The coalescing medium assembly includes a plurality of wire mesh tubes oriented substantially parallel to each other. A wire mesh retaining wall substantially surrounds the tubes and holds the tubes together. The invention comprises, in yet another form thereof, a coalescing medium assembly for removing air or debris from a flow of liquid. The coalescing medium assembly includes an elongate core element having a longitudinal axis extending in a longitudinal direction. The elongate core element also has at least one substantially continuous side surface facing in a lateral direction substantially perpendicular to the longitudinal direction. Wire mesh tubes surround the core element and are oriented substantially parallel to the core element. An advantage of the present invention is that a planar wire mesh can be easily cut into sections that are easily rolled into tubes. A larger section of the planar wire mesh can be easily wrapped around the wire mesh tubes to thereby retain the tubes against a central solid cylindrical tube. Thus, the apparatus of the present invention can be quickly, easily and inexpensively manufactured. Another advantage is that the resulting wire mesh tubes can be easily handled, assembled together and/or inserted into a shell cavity. Yet another advantage is that the wire mesh can be formed of inexpensive and durable stainless steel. Thus, the coalescing medium formed of the wire mesh does not need to be frequently replaced. The above mentioned and other features and objects of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: FIG. 1 is a schematic cross-sectional front view of one embodiment of an apparatus of the present invention for removing air or debris from a flow of liquid; FIG. 2 is a perspective view of one embodiment of a coalescing medium assembly of the apparatus of FIG. 1; FIG. 3 is an exploded, partially fragmentary, perspective view of the coalescing medium assembly of FIG. 2; FIG. 4 is a plan view of a piece of wire mesh from which a wire mesh tube of the coalescing medium assembly of FIG. 2 can be formed; FIG. 5 is a top view of the coalescing medium assembly of FIG. 2; FIG. 6 is a schematic, partially exploded front view of another embodiment of an apparatus of the present invention for removing air or debris from a flow of liquid; FIG. 7 is a top view of the apparatus of FIG. 6 along line 7-7; and FIG. 8 is a top schematic view of another embodiment of a coalescing medium assembly of the present invention. Corresponding reference characters indicate corresponding parts throughout the several views. Although the exemplification set out herein illustrates embodiments of the invention, in several forms, the embodiments disclosed below are not intended to be exhaustive or to be construed as limiting the scope of the invention to the precise forms disclosed. Referring now to the drawings, and particularly to FIG. 1, there is shown one embodiment of an apparatus 10 of the present invention for removing entrained air and air microbubbles 12 and/or particles of dirt or debris 14 from a flow of liquid, such as a flow of water 16. Apparatus 10 includes a shell 18 having an inlet 20, an outlet 22, and an elongate inner cavity 24 in fluid communication with each of inlet 20 and outlet 22. Shell 18 also includes a one-way venting device 26 for releasing air bubbles from cavity 24, and a removable bottom section 28. Bottom section 28 can be separated from the remainder of shell 18 in order to insert a coalescing medium assembly 30 into cavity 24, or to remove assembly 30 therefrom, such as for cleaning. Coalescing medium assembly 30 is indicated only schematically in FIG. 1, as the structural details of assembly 30 will be discussed in detail below. Bottom section 28 includes a valve 32 through which settled dirt particles 34 can be selectively drained or otherwise removed from bottom section 28. Shell 18 also includes a valve 36 through which the pressure at the top of cavity 24 can be selectively equalized with ambient air pressure. In operation, a flow of water 16 including entrained air and air microbubbles 12 and dirt particles 14 passes through inlet 20 via a conduit 38. The speed of the flow is reduced in cavity 24 by virtue of the larger cross-sectional area of cavity 24 in comparison with that of conduit 38. Dirt particles 14 may impinge upon coalescing medium assembly 30, which can cause particles 14 to fall into bottom section 28, as indicated by arrows 40. Thus, coalescing medium assembly 30 strains or filters dirt particles 14 from the flow of water 16. Entrained air is pulled out of solution in cavity 24 and forms microbubbles 42 that cling to coalescing medium assembly 30. Microbubbles 42 and other microbubbles 12 from water flow 16 collect and coalesce on coalescing medium assembly 30 to form larger air bubbles 44. Larger bubbles 44 can quickly rise to the top of cavity 24 and pass through venting device 26 to ambient air, as indicated by arrow 46. The flow of water 16, having had air and/or debris at least partially removed therefrom, exits cavity 24 via outlet 22 and conduit 47. One embodiment of coalescing medium assembly 30 of FIG. 1 is shown in FIG. 2. Assembly 30 includes an elongate core element in the form of a cylindrical tube 48. Tube 48 can be hollow and open ended to allow the coalescing of bubbles on both an interior annular surface and an exterior annular surface of tube 48. Tube 48 is surrounded by six wire mesh tubes 50 which are oriented substantially parallel to tube 48. That is, wire mesh tubes 50 form a "ring" around tube 48. A wire mesh retaining wall 52 substantially surrounds wire mesh tubes 50, thereby holding tubes 50 together in engagement with each other and with central tube 48. The individual components of assembly 30 may be best seen in the exploded view of FIG. 3. Only a fragment of retaining wall 52 is shown in FIG. 3 in order to maintain clarity in the drawing. Central cylindrical tube 48 has a longitudinal axis 54 extending in a longitudinal direction indicated by double arrow 56. Tube 48 also has a substantially continuous annular side surface 58 facing in lateral or radial directions 60 away from axis 54 and substantially perpendicular to longitudinal direction 56. The continuousness of surface 58 provides increased surface area on which air bubbles can coalesce, thereby facilitating the removal of air from the flow of water 16. Surface 58 is substantially continuous in that it has few if any holes or perforations that would reduce its surface area available for the coalescing of bubbles. The continuousness of surface 58 also provides tube 48 and assembly 30 with structural strength to withstand the force of a high speed flow of water. The six wire mesh tubes 50 can be substantially identical. Each tube 50 can be rolled into a tubular shape from a planar, rectangular piece of wire mesh 62 (FIG. 4). Although tubes 50 are not continuous cylinders (as is tube 48), and do not convey a fluid in longitudinal directions 56, they are referred to herein as "tubes" by virtue of their tubular shape. Wire mesh 62 can have approximately four strands of wire per inch in both longitudinal directions 56 and lateral direction 60. The diameter of the wire can be approximately between 0.02 inch and 0.04 inch. In one embodiment, the wire has a diameter of 0.032 inch. Of course other sizes of mesh, including different wire densities and thicknesses, are also possible. During manufacture of a tube 50, a narrow, longitudinally oriented strip 64, defined as being a portion of wire mesh 62 that is disposed to the right-hand side of the dashed line in FIG. 4, can be gripped by a rolling machine (not shown). As the rolling machine rolls a remainder 66, defined as being a portion of wire mesh 62 that is disposed to the left-hand side of the dashed line in FIG. 4, a side edge 68 of mesh 62 can overlap strip 64 and can possibly overlap an additional portion of mesh 62 that is adjacent to strip 64, as best seen in FIG. 5. Thus, once tube 50 has been rolled from wire mesh 62, strip 64 takes the form of a projection extending from an inner surface 70 of tube 50 into an interior 72 of tube 50. It is to be understood, however, that it is not necessary for side edge 68 to overlap any other part of mesh 62. That is, there can be a gap between side edge 68 and strip 64 such that the circumference of tube 50 does not form a closed loop. Projection 64 has the advantage of providing additional surface area on tube 50 on which bubbles can coalesce. In an alternative embodiment, the strip gripped by the rolling machine can have an increased width such that a resulting projection 74 extends almost across the entire width or diameter of the wire mesh tube. Projection 74 provides still greater surface area for coalescing as compared to projection 64. In another alternative embodiment, an elongate surface area-providing element in the form of a strip 76, possibly formed of stainless steel, is inserted into each wire mesh tube in order to provide additional surface area for facilitating the coalescing of bubbles. Strip 76 can extend the entire length of the wire mesh tube in longitudinal directions 56. In yet another alternative embodiment (not shown), strip 76 is bent in half at a 90° angle along a line of articulation extending in directions 56, i.e., strip 76 is bent in a direction that is in the plane of FIG. 5. A second similarly bent strip 76 can be inserted into the wire mesh tube such that the two bent strips 76 form a substantially X-shaped pattern, thereby further increasing the useful surface area for coalescing. Strip 76 can be formed of a continuous sheet or of a mesh material. As best seen in FIG. 5, the six wire mesh tubes 50 and central tube 48 have substantially equal widths or diameters. For example, the outer diameters of tubes 48, 50 can be approximately between 0.4 inch and 0.8 inch. In particular embodiments, the outer diameters of tubes 48, 50 can be approximately 0.50 inch or 0.75 inch. The substantially equal diameters of tubes 48, 50 allows wire mesh tubes 50 and central tube 48 to be packed tightly together such that each tube 50 can engage both tube 48 and two adjacent ones of tubes 50. Thus, when inserted into a cavity having a round cross-sectional area and a corresponding interior diameter, such as cavity 24, tubes 48 and 50 can be substantially immovable, even without the benefit retaining wall 52, by virtue of the tight packing of tubes 48, 50. Since tubes 48, 50 are substantially immovable, tubes 48, 50 are less likely to be pushed away from inlet 20 and toward outlet 22 by the force of water flow 16, which can be approximately 3500 gallons per minute in some applications. By virtue of tubes 48, 50 being evenly distributed about cavity 24, it has been found that the coalescing of bubbles is facilitated. It has also been found that the even distribution of tubes 48, 50 within cavity 24 enables the flow rate to be increased with little or no reduction in the air and debris-removing capability of apparatus 10. Wire mesh retaining wall 52 can be formed of the same wire mesh material of which wire mesh tubes 50 are formed. Retaining wall 52 can be formed from a planar, rectangular piece of the wire mesh (not shown). Retaining wall 52 can be wrapped around tubes 50 such that opposite side edges 78, 80 of retaining wall 52 overlap each other. It is to be understood, however, that it is not necessary for side edges 78, 80 to overlap each other. That is, there can be a gap between edges 78 and 80 such that the circumference of retaining wall 52 does not form a closed loop. One or more bands 82 can be wrapped around retaining wall 52 in order to hold or bias retaining wall 52 in engagement with tubes 50. A clasp 84 may be used to secure overlapping portions of a band 82 together such that band 82 is kept tight against retaining wall 52, and retaining wall 52, in turn, is kept tight against tubes 50. If a cavity, such as cavity 24, is of an appropriate, corresponding width, it is possible to insert tubes 48, 50 into the cavity without retaining wall 52 and bands 82. In this case, an interior surface 86 of shell 18 can hold tubes 48, 50 substantially immovably in position. Another embodiment of the present invention is shown in FIG. 6 as apparatus 110. Similarly to apparatus 10, apparatus 110 removes entrained air and air microbubbles and/or particles of dirt or debris from a flow of liquid, such as a flow of water. Apparatus 110 includes a shell 118 having an inlet 120, an outlet 122, and an elongate inner cavity 124 in fluid communication with each of inlet 120 and outlet 122. Shell 118 also includes a removable bottom section 128 and/or a removable top section 129. One or both of bottom section 128 and top section 129 can be separated from the remainder of shell 118 in order to insert a plurality of coalescing medium assemblies 130 into cavity 124, or to remove assemblies 130 therefrom. Coalescing medium assemblies 130 are indicated only schematically in FIG. 6, as the structural details of assemblies 130 will be discussed in detail below. Shell 118 can also include a venting device and/or one or more valves for releasing gas, equalizing pressure and/or removing dirt particles, similarly to shell 18. However, such a venting device and valves are not shown in FIG. 6 in order to simplify the drawing. A venting port 126 for enabling the escape of air from cavity 124 and into the ambient environment is schematically indicated in FIG. 6. The width of each individual assembly 130 can be approximately equal to the width of each individual assembly 30, e.g., approximately 2.25 inches. However, the width or diameter of cavity 124 can be several times greater than the width of cavity 24, and thus more than one assembly 130 can be inserted into cavity 124. For example, the width of cavity 124 can be approximately 7.75 inch such that seven coalescing medium assemblies 130 each of approximately 2.25 inch width can fit into cavity 124, as shown in FIG. 7. With the dimensional relationships between cavity 124 and assemblies 130 being as shown in FIG. 7, an interior surface 186 of shell 118 can hold assemblies 130 substantially immovably in position. In an alternative embodiment (not shown), the width of the shell cavity is approximately 24 inches. Approximately 70 coalescing medium assemblies, each having a width of approximately between 2.25 inches and 2.50 inches, are inserted into the shell cavity, thereby substantially filling the shell cavity to fully capacity. Each assembly 130 can include a central cylindrical tube 148 having a length in longitudinal direction 56 that is greater than the lengths of wire mesh tubes 150. Thus, the opposite ends of tubes 148 can extend past the opposite ends 151 of adjacent tubes 150, as best seen in FIG. 6. As another means of holding assemblies 130 immovably in position, at least one end cap 133 having a plurality of recesses in the form of throughholes 135 can be provided within cavity 124. Throughholes 135 are sized and positioned such that each throughhole 135 can receive an end of a corresponding one of central tubes 148. With central tubes 148 being received in one or both end caps 133, coalescing assemblies 130 can be retained in position as a group together with other coalescing assemblies 130. Thus, the use of one or both end caps 133 makes it easier to simultaneously insert a group of coalescing assemblies 130 into cavity 124. Other aspects of coalescing medium assemblies 130 are substantially similar to those of coalescing medium assemblies 30, and thus are not discussed in detail herein. For example, each coalescing medium assembly 130 can include a wire mesh retaining wall 152 and one or more bands 182. In operation, a water flow including air and/or dirt particles enters cavity 124 through inlet 120, is filtered by coalescing medium assemblies 130 to remove at least some of the air and/or dirt therefrom, and exits cavity 124 through outlet 122. In order to inhibit the water flow from bypassing coalescing medium assemblies 130 in its route from inlet 120 to outlet 122, inlet 120 and outlet 122 are disposed at locations along the longitudinal direction 56 that are between opposite ends 151 of coalescing medium assemblies 130. In another embodiment of a coalescing medium assembly 230 shown in FIG. 8, the diameters of four wire mesh tubes 250 are unequal to the diameter of a central cylindrical tube 248. However, as is the case with equal-diameter tubes 48, 50, there is a dimensional relationship between the diameters of tubes 248, 250 such that when tubes 250 are arranged in a circular arrangement, tube 248 can engage, i.e., touch, each of tubes 250 simultaneously. More particularly, tubes 250 are arranged such that the centers of tubes 250 define an imaginary circle 253 and each tube 250 engages two adjacent tubes 250. Central tube 248 is sized such that tube 248 can engage each of tubes 250 when disposed at the center of circle 253. Thus, despite tubes 248, 250 being of different diameters, it is possible to tightly pack tubes 248, 250 into a shell cavity, or to tightly wrap tubes 248, 250 with a retaining wall 252, such that tubes 248, 250 are substantially immovable during operation. Other aspects of coalescing medium assembly 230 are substantially similar to those of coalescing medium assembly 30, and thus are not discussed in detail herein. For example, coalescing medium assembly 230 can include one or more bands 282 each secured by a respective clasp 284. It is also possible for a coalescing medium assembly to include wire mesh tubes of different sizes. For example, in the embodiment of FIG. 8, additional wire mesh tubes, such as a schematically-indicated wire mesh tube 350, can be inserted into gaps between tubes 250 and 252. As is clear in FIG. 8, the diameter of tube 350 is less than the diameters of tubes 250. Additional tubes 350 may provide enhanced structural support as well as increased surface area for the coalescing of air bubbles and the filtering of dirt particles. It is to be understood that each component of the various embodiments discussed above can be formed of stainless steel for its structural strength, low cost and durability. Components exposed to the flow of water that is being filtered, such as central tubes, wire mesh tubes, wire mesh retaining walls and bands, can particularly benefit from being formed of stainless steel. However, it is also possible for any of the components to be formed of a material other than stainless steel, such as copper for example. It is also to be understood that the present invention is not limited to any particular number or arrangement of wire mesh tubes, tubes having continuous side surfaces and/or retaining walls. Nor is the present invention limited to any positional relationship between such various tubes and/or retaining walls. A few exemplary arrangements or positional relationships have been disclosed herein, but there are many other ways that the various tubes and retaining walls can be arranged within the scope of the invention. The tube having a substantially continuous side surface has been described, shown, and referred to herein as being a "central" tube. However, it is also possible within the scope of the invention for a tube having a substantially continuous side surface to not be centrally located among the wire mesh tubes. For example, a coalescing medium assembly can include two tubes having substantially continuous side surfaces, with both tubes being disposed within a cluster of wire mesh tubes, but with neither tube being centrally positioned within the cluster. The coalescing medium assemblies of the present invention have been shown herein as including a single "ring" of wire mesh tubes surrounding and engaging a central tube that has a substantially continuous side surface. However, it is also possible for a coalescing medium assembly to include a second "ring" of wire mesh tubes surrounding and engaging the first ring of wire mesh tubes. While this invention has been described as having an exemplary design, the present invention may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. | 20040121 | 20120515 | 20050721 | 82438.0 | 1 | KURTZ, BENJAMIN M | APPARATUS FOR REMOVING AIR AND/OR DEBRIS FROM A FLOW OF LIQUID | SMALL | 0 | ACCEPTED | 2,004 |
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10,762,134 | ACCEPTED | Irrigation unit including a power generator | An irrigation unit (20) for irrigating an area (12) with a fluid (19) from a fluid source (18) includes a housing (200), a nozzle (220), an electronic component (221), and a power generator (230). The nozzle (220) is directly or indirectly secured to the housing (200) and the nozzle (220) is in fluid communication with the fluid source (18) so that fluid (19) from the fluid source (18) is transferred to the nozzle (220). The electronic component (221) is directly or indirectly secured to the housing (200). The power generator (230) generates electrical energy that is transferred to the electronic component (221). The power generator (230) directly transfers at least a portion of the electrical energy to the electronic component (221) of the irrigation unit (20). The electronic component (221) can be a power storage unit (222) for storing electrical energy for use by the irrigation unit (20). | 1. An irrigation unit for irrigating an area with a fluid from a fluid source, the irrigation unit comprising: a housing; a nozzle that is secured to the housing, the nozzle being in fluid communication with the fluid source so that fluid from the fluid source is transferred to the nozzle; an electronic component coupled to the housing; and a power generator that generates electrical energy, the power generator directly transferring at least a portion of the electrical energy to the electronic component, the power generator including a generator and a turbine that is in fluid communication with the fluid source, wherein the flow of the fluid from the fluid source to the nozzle causes the turbine to rotate the generator to generate electrical energy. 2. (canceled) 3. (canceled) 4. (canceled) 5. (canceled) 6. The irrigation unit of claim 1 wherein the power generator is positioned near the housing. 7. The irrigation unit of claim 1 wherein the power generator is secured to the housing. 8. The irrigation unit of claim 1 wherein the power generator is positioned within the housing. 9. The irrigation unit of claim 1 wherein the electronic component is a power storage unit. 10. The irrigation unit of claim 1 wherein the electronic component is a control system. 11. An irrigation system including a main control system and the irrigation unit of claim 1. 12. An irrigation unit for irrigating an area with a fluid from a fluid source, the irrigation unit comprising: a housing; a nozzle that is secured to the housing, the nozzle being in fluid communication with the fluid source so that fluid from the fluid source is transferred to the nozzle; an electronic component coupled to the housing; and a power generator including a generator and turbine that rotates the generator to generate electrical energy, the power generator being positioned near the housing, the power generator being electrically connected to the electronic component. 13. The irrigation unit of claim 12 wherein the power generator directly transfers at least a portion of the electrical energy to the electronic component. 14. (canceled) 15. The irrigation unit of claim 12 wherein the power generator includes a turbine that is in fluid communication with the fluid source and wherein flow of the fluid from the fluid source to the nozzle causes the turbine to rotate and the power generator to generate electrical energy. 16. (canceled) 17. The irrigation unit of claim 12 wherein the power generator is positioned near the housing. 18. The irrigation unit of claim 12 wherein the power generator is secured to the housing. 19. The irrigation unit of claim 12 wherein the power generator is positioned within the housing. 20. The irrigation unit of claim 12 wherein the electronic component is a power storage unit. 21. The irrigation unit of claim 12 wherein the electronic component is a control system. 22. An irrigation system including a main control system and the irrigation unit of claim 12. 23. An irrigation unit for irrigating an area with a fluid from a fluid source, the irrigation unit comprising: a housing; a nozzle that is secured to the housing, the nozzle being in fluid communication with the fluid source so that fluid from the fluid source is transferred to the nozzle; an electronic component coupled to the housing; a power storage unit that stores electrical energy, the power storage unit being electrically connected to the electronic component; and a power generator including a generator and a turbine that rotates the generator to generate electrical energy, the power generator being positioned near the housing, the power generator being electrically connected to the electronic component. 24. The irrigation unit of claim 23 wherein the power storage unit includes a battery. 25. The irrigation unit of claim 23 wherein the power storage unit includes a capacitor. 26. The irrigation unit of claim 23 wherein the power storage unit is positioned near the housing. 27. The irrigation unit of claim 23 wherein the power storage unit is secured to the housing. 28. The irrigation unit of claim 23 wherein the power storage unit is positioned within the housing. 29. (canceled) 30. An irrigation system including a main control system and the irrigation unit of claim 23. 31. A method for irrigating an area with a fluid from a fluid source, the method comprising the steps of: providing a housing; securing a nozzle to the housing, the nozzle being in fluid communication with the fluid source so that fluid from the fluid source is transferred to the nozzle; coupling an electronic component to the housing; and directly transferring electrical energy from a power generator to the electronic component, the power generator including a rotating turbine that rotates a generator to generate electrical energy. 32. (canceled) 33. The method of claim 31 further comprising the step of positioning the turbine in fluid communication with the fluid source so that flow of the fluid from the fluid source to the nozzle causes the turbine to rotate. 34. The method of claim 31 further comprising the step of positioning the power generator near the housing. 35. The method of claim 31 further comprising the step of securing the power generator to the housing. 36. A method for irrigating an area with a fluid from a fluid source, the method comprising the steps of: providing a housing; securing a nozzle to the housing, the nozzle being in fluid communication with the fluid source so that fluid from the fluid source is transferred to the nozzle; coupling an electronic component to the housing; storing electrical energy with a power storage unit that is electrically connected to the electronic component; and directly transferring electrical energy from a power generator to the electronic component, the power generator including a rotating turbine that rotates a generator to generate electrical energy. 37. The method of claim 36 further comprising the step of securing the power storage unit to the housing. 38. The method of claim 36 further comprising the step of positioning the power storage unit within the housing. | BACKGROUND Water is becoming an increasingly valuable and scarce commodity both in the United States and abroad. In particular, extreme drought conditions are common in arid regions such as the desert southwestern United States, although a decreased level of precipitation and resulting low water supplies can occur just about anywhere at various times. To compound matters, substantial amounts of water are squandered due to inefficient and ineffective conventional irrigation systems, for a variety of reasons. For example, typical irrigation units distribute water in a full round, half-round, quarter-round or an adjustable-type circular pattern. Thus, no matter how the irrigation units are arranged, obtaining consistent water coverage over a rectangular watering area is difficult or impossible. Watering normally occurs to prevent brown spots, resulting in overwatering in basically all other areas. In fact, in order to ensure that all areas are adequately irrigated, overlapping spray regions occur, which can result in certain areas receiving 300% or more of the necessary amount of water. Further, runoff from elevated areas such as mounds, slopes or hills causes ponding in lower areas, which can ultimately result in the higher areas absorbing an insufficient amount of water, while the lower areas are being saturated with water. Thus, watering occurs indiscriminately whether certain areas of the ground are wet or dry. In addition, in hot, windy conditions, water has a higher evaporation rate and may not actually reach the ground in the intended location, if at all. Moreover, different types of grass, trees or other foliage require varying levels of irrigation. These problems are exacerbated when the watering area is irregularly-shaped and includes areas that do not require water, such as walkways, driveways, fountains, ponds or other surfaces or features. Consequently, a significant quantity of water is routinely wasted, resulting in higher water bills and lower reservoirs. Further, the cost for pumping large amounts of water can result in increasingly high electrical expenses. In large turf areas, such as on golf courses, excessive and inefficient watering can give rise to enormous costs to the owner, thereby making maintaining a lush, green golf course prohibitive. Further, turf and soil maintenance is significantly increased due to the deposits of minerals, chemicals and salts that are left in the soil from irrigation. This is particularly a problem where reclaimed water having a high total dissolved solids (TDS) content is used for irrigation. These minerals, chemicals and salts can reduce absorption of the water into the soil, can change the pH of the soil, and/or can make the soil excessively salty, inhibiting growth of vegetation in the soil. SUMMARY The present invention is directed to an irrigation system that includes one or more irrigation units for irrigating an area with a fluid from a fluid source. In one embodiment, the irrigation unit includes a housing, a nozzle, an electronic component, and a power generator. The nozzle is directly or indirectly secured to the housing and the nozzle is in fluid communication with the fluid source so that fluid from the fluid source is transferred to the nozzle. The electronic component is directly, indirectly, mechanically and/or electrically secured and/or coupled to the housing. The power generator generates electrical energy that is transferred to the electronic component. With this design, separate electrical power lines do not have to be directed to each of the irrigation units of the irrigation system. In one embodiment, the power generator directly transfers at least a portion of the electrical energy to the electronic component of the irrigation unit. As provided herein, the power generator can be a turbine type generator having a turbine that is in fluid communication with the fluid source. With this design, flow of the fluid from the fluid source to the nozzle causes the turbine to rotate and the power generator to generate electrical energy. Alternatively, for example, the power generator can include a solar panel or a water electrolysis unit that generates electrical energy. The power generator can be positioned near and/or within the housing. Moreover, the power generator can be directly or indirectly secured to the housing. For example, the electronic component can be a power storage unit, a control system, and/or another type of component that utilizes, stores, or transfers electrical energy. The power storage unit can include one or more batteries and/or capacitors. The present invention is also directed to an irrigation system that includes an irrigation unit, a method for generating electrical energy for an irrigation unit, and a method for storing electrical energy for an irrigation unit. BRIEF DESCRIPTION OF THE DRAWINGS The novel features of this invention, as well as the invention itself, both as to its structure and its operation, will be best understood from the accompanying drawings, taken in conjunction with the accompanying description, in which similar reference characters refer to similar parts, and in which: FIG. 1A is a top plan view of a hole of a golf course and an automated irrigation assembly having features of the present invention; FIG. 1B is a detailed top plan view of a portion of the hole illustrated in FIG. 1A, including a first embodiment of a plurality of irrigation regions; FIG. 1C is a detailed top plan view of a portion of the hole illustrated in FIG. 1A, including a second embodiment of a plurality of irrigation regions; FIG. 1D is a detailed top plan view of one of the irrigation regions illustrated in FIG. 1C, including a plurality of irrigation subregions; FIG. 1E is a detailed top plan view of a portion of the hole illustrated in FIG. 1A, including a third embodiment of a plurality of irrigation regions; FIG. 1F is a detailed top plan view of one of the irrigation regions illustrated in FIG. 1E, including a plurality of irrigation subregions; FIG. 2A is a perspective view of an irrigation unit having features of the present invention illustrated in a retracted position; FIG. 2B is a perspective view of the irrigation unit illustrated in FIG. 2A in an extended position; FIG. 2C is a top plan view of the irrigation unit illustrated in FIG. 2A; FIG. 2D is a cut-away view of a first section of the irrigation unit illustrated in FIG. 2A; FIG. 2E is a top plan view of an alternative irrigation unit having features of the present invention; FIG. 2F is a front plan view of a third section of the irrigation unit illustrated in FIG. 2A; FIG. 2G is a cut-away view of the third section of the irrigation unit taken on line 2G-2G in FIG. 2F; FIG. 2H is a cut-away view of the third section of the irrigation unit taken on line 2H-2H in FIG. 2F; FIG. 2I is a perspective view of another embodiment of the irrigation unit; FIG. 2J is a perspective view of yet another embodiment of the irrigation unit; and FIG. 3 is a simplified block diagram showing the electrical components of a main control system in communication with the irrigation units in accordance with the present invention. DESCRIPTION The present invention provides an automated irrigation system (also referred to herein simply as “irrigation system”) and method for selectively irrigating a specific area. The configuration and type of area with which the irrigation system provided herein can be used can vary widely. For ease of understanding, a portion of a golf course is described herein as a representative area that can be irrigated with the present invention. However, it is recognized that any area in need of irrigation, regardless of size or location, can benefit from use with the irrigation system provided herein. For example, the irrigation system 10 can be used for irrigating a lawn, a sports field, agricultural crops and other vegetation, a cemetery, a park, or any other suitable area. A number of Figures include an orientation system that illustrates an X axis, a Y axis that is orthogonal to the X axis, and a Z axis that is orthogonal to the X and Y axes. It should be noted that these axes can also be referred to as the first, second and third axes. FIG. 1A is a top plan view of an automated irrigation system 10 having features of the present invention installed on a golf course 12 (only a portion of the golf course 12 is illustrated for clarity). More specifically, the portion of the golf course 12 illustrated in FIG. 1A includes one golf hole 14, although it is recognized that any number of golf holes 14 can be included in the golf course 12. The typical golf hole 14 can include a plurality of features, such as (i) one or more tee areas 16A, (ii) one or more trees, bushes or other plants (also referred to herein as “vegetation” 16B), (iii) one or more areas of relatively short turf growth (also referred to herein as a “fairway” 16C), (iv) one or more areas of longer turf growth (also referred to herein as “rough” 16D), (v) a green 16E, (vi) one or more sand traps 16F, (vii) one or more natural or manmade water features 16G such as lakes, streams, ponds, waterfalls, etc., (viii) a cart path 16H or vehicle access road, (ix) a natural or manmade rock formation 16I, and/or (x) walkways 16J, paths or bridges, as non-exclusive examples. In one embodiment, one or more of the water features 16G can serve as a fluid source 18 that uses a pump (not shown) or other suitable means to supply irrigation fluid 19 for the irrigation system 10. Alternatively, the fluid source 18 can be a water tank or other receptacle (not shown), or an offsite water source (not shown), such as a lake, river, stream or the like. Still alternatively, the fluid source 18 can include water from a municipal or reclaimed water source, as non-exclusive examples. The type of irrigation fluid 19 utilized can vary according to the type of ground cover and the features 16A-J on the golf course 12. The irrigation fluid 19 can be (i) water, (ii) reclaimed water, (iii) waste water, (iv) water with amendments, additives, chemicals, and/or pesticides, or (v) another suitable type of fluid, as non-exclusive examples. In one embodiment, the irrigation system 10 precisely provides irrigation fluid 19 to those features that normally would require irrigation fluid 19, such as the tee areas 16A, the vegetation 16B, the fairway 16C, and the green 16E. On the other hand, in one embodiment, the irrigation system 10 inhibits and/or minimizes the application of the irrigation fluid 19 on various other features, such as the sand traps 16F, the water features 16G, the cart paths 16H, the rock formations 16I and the walkways 16J. As provided herein, the irrigation system 10 can selectively and efficiently distribute the irrigation fluid 19 to specific areas, while reducing or eliminating the application of irrigation fluid 19 to other areas. Additionally, the rough 16D may require irrigation fluid 19 depending upon the type of grass or other planting material included in the rough 16D and the desired condition of such grass or vegetation. For instance, if the rough 16D includes grass areas, irrigation fluid 19 may be required. However, if the rough 16D includes bark, mulch, dirt, sand or other ground cover that would not require irrigation fluid 19, the irrigation system 10 reduces or eliminates applying irrigation fluid 19 to those areas, as described in greater detail below. With this design, a decreased quantity of irrigation fluid 19 is required, thereby lowering water costs. Further, inhibiting watering of cart paths 16H and walkways 16J decreases the likelihood of (i) a golf cart losing traction, or (ii) the creation of a slip and fall hazard for a golfer, as examples. The irrigation system 10 illustrated in FIG. 1A includes (i) a plurality of spaced apart irrigation units 20, each having a unit power source 230 (illustrated in FIG. 2D), (ii) a main control system 22, and (iii) an auxiliary power source 24. As provided in greater detail below, the irrigation units 20, the main control system 22 and the auxiliary power source 24 cooperate to distribute irrigation fluid 19 from one or more of the fluid sources 18 to specific regions of the golf course 12. In an alternative embodiment, and as explained in detail below, no auxiliary power source 24 is required. In one embodiment, the auxiliary power source 24 can be in electrical communication with the main control unit 22 and/or the irrigation units 20. In the embodiment illustrated in FIG. 1A, the main control system 22 can be in electrical communication with one or more of the irrigation units 20 via a power line 26 and/or a data line 28. In an alternative embodiment, a single line can operate as both the power line 26 and the data line 28. Still alternatively, either or both of the power or data lines between the main control system 22 and the individual irrigation units 20 are not necessary. The arrangement and positioning of the irrigation units 20 can vary depending upon the configuration and the water requirements of the features 16A-J on the golf course 12. Further, because the irrigation system 10 provided herein can be retrofitted for use with an existing irrigation system (not shown) as provided in greater detail below, the positioning of the irrigation units 20 described herein may also be at least partly dependent upon the location of existing irrigation units (not shown) to be retrofitted, although this is not a requirement of the present invention. In the embodiment illustrated in FIG. 1A, the irrigation units 20 are arranged in a pattern that includes one or more rows. Alternatively, the irrigation units 20 can be arranged in a different pattern, or can be randomly placed on the golf course 12. FIG. 1B is an enlarged view of the dashed rectangular area 1B illustrated in FIG. 1A. In the embodiment illustrated in FIG. 1B, the golf hole 14 includes a plurality of irrigation regions 30 (illustrated with grid lines 31). Although the irrigation regions 30 illustrated in FIG. 1B are substantially square, any shape can be used for the irrigation regions 30. For example, the geometry of each irrigation region 30 can be circular, oval, rectangular, triangular, trapezoidal, hexagonal, or can have another suitable configuration. Further, the golf hole 14 can utilize a combination of geometries for the irrigation regions 30. Additionally, the size of each irrigation region 30 can be varied. In one embodiment, each irrigation region 30 can be a square that is approximately 80 feet×80 feet. However, the irrigation region 30 can have a larger or smaller area, depending upon the design requirements of the irrigation units 20. In alternative embodiments, the irrigation region 30 can be 25 feet×25 feet, 40 feet×40 feet, 60 feet×60 feet, or 100 feet×100 feet, as non-exclusive examples. In this embodiment, each irrigation region 30 is serviced by a corresponding irrigation unit 20. Further, in the embodiment illustrated in FIG. 1B, the irrigation regions 30 and the irrigation units 20 within the irrigation regions 30 are aligned in substantially straight rows along the golf hole 14, and are connected with subterranean irrigation lines 32 (some representative irrigation lines 32 are shown in phantom in FIG. 1B) to the fluid source 18. As an overview, in one embodiment, each irrigation unit 20 is programmed to precisely apply the appropriate quantity of irrigation fluid 19, as necessary, to only those portions of the corresponding irrigation region 30 that require irrigation fluid 19. Additionally, in one embodiment, should the irrigation fluid 19 requirements change over time within the irrigation region 30, the irrigation unit 20 will accordingly modify the quantity of irrigation fluid 19 applied within the irrigation region 30, as provided herein. The irrigation system 10 can use existing irrigation lines 32 in the event of a retrofit. Alternatively, the existing irrigation lines 32 can be abandoned, or a portion of the existing irrigation lines 32 can be utilized. Still alternatively, new irrigation lines 32 can be installed below the surface of the ground in any pattern necessary to effectuate the intent of the present invention. The irrigation lines 32 can be formed from plastics such as polyvinylchloride (PVC), various metals, or any other suitable materials. FIG. 1C is another embodiment of a portion of a golf hole 14C. In this embodiment, the irrigation units 20 are not aligned in rows. Instead, at least some of the irrigation units 20 can be offset along either the X axis, the Y axis, or along both the X and Y axes. Stated another way, the irrigation units 20 can be specifically positioned to increase the effective watering area of each irrigation unit 20. As used herein, the effective watering area of one irrigation unit 20 within one irrigation region 30 is defined as the percentage of the surface area within the irrigation region 30 that requires irrigation fluid 19. Thus, an irrigation unit 20 that is positioned immediately adjacent to the water feature 16G may have an effective watering area of approximately 50%. Other features 16F, 16H, 16I, 16J (illustrated in FIG. 1A) that do not require irrigation fluid 19 can influence the effective watering area upwards or downwards. In another example, an irrigation unit 20 that is positioned in the middle of the fairway 16C may have an effective watering area of approximately 100%. For example, because arranging the irrigation units 20 in substantially straight rows can be somewhat functionally arbitrary, the effective watering area of one or more irrigation units 20 can be somewhat reduced due to the presence of one or more features 16A (illustrated in FIG. 1A), 16B-D, 16E (illustrated in FIG. 1A), 16F-J within the irrigation region 30. Thus, in the embodiment illustrated in FIG. 1C, the irrigation units 20 are positioned so that the effective watering area of each irrigation region 30 is optimized. It is recognized that the irrigation lines 32 must likewise be positioned to provide irrigation fluid 19 to the irrigation units 20, which may necessitate relocation of existing irrigation lines 32 in the event of a retrofit, or placement of new subterranean irrigation lines 32 for a new installation of the irrigation system 10. FIG. 1D is a detailed top plan view of a representative irrigation region 30 from the golf hole 14C illustrated in FIG. 1C. In this example, the irrigation region 30 includes the irrigation unit 20, vegetation 16B, a fairway 16C, rough 16D, a sand trap 16F, a cart path 16H, and one or more alignment guides 38. In one embodiment of the irrigation system 10, the irrigation region 30 is divided into a plurality of irrigation subregions 34 (also referred to herein as “subregions”). The size, number and configuration of the irrigation subregions 34 can vary depending upon the irrigation requirements of the golf course 12, the configuration of the irrigation region 30, and the features 16A-J included within the irrigation region 30, as examples. For convenience, in the embodiment illustrated in FIG. 1D, the irrigation region 30 includes 100 substantially square irrigation subregions 34, arranged in a ten by ten grid pattern 36. In this embodiment, assuming an irrigation region having dimensions of 80 feet×80 feet, each irrigation subregion 34 would be 8 feet×8 feet. However, the grid pattern 36 can have any suitable dimensions. For example, the irrigation region 30 can be divided into a 20 by 20 grid pattern 36 so that the irrigation subregions 34 in this example would be 4 feet×4 feet. In one embodiment, the subregions 34 of a given irrigation region 30 have approximately the same shape. In another embodiment, the subregions 34 of a give irrigation region 30 have approximately the same area. In still other embodiments, the subregions 34 can have differing shapes and/or areas within a given irrigation region 30. Moreover, the subregions 34 can be arranged so that they do not overlap, as illustrated in FIG. 1D. In the embodiment illustrated in FIG. 1D, the irrigation subregions 34 are arranged on a standard X-Y coordinate scale. In this example, the irrigation subregion 34 in the lower left-hand corner is referred to herein as subregion (X1, Y1), the irrigation subregion 34 in the lower right-hand corner is referred to herein as subregion (X10, Y1), the irrigation subregion 34 in the upper left-hand corner is referred to herein as subregion (X1, Y10), and the irrigation subregion 34 in the upper right-hand corner is referred to herein as subregion (X10, Y10). Further, the irrigation unit 20 is centrally positioned at the corner of subregions (X5, Y5), (X5, Y6), (X6, Y5) and (X6, Y6). However, the positioning of the irrigation unit 20 within the irrigation region 30 need not be centrally located. In fact, depending upon the configuration of the irrigation region 30 and the features 16A-J included within the irrigation region 30, it may be advantageous to offset the positioning of the irrigation unit 20. The alignment guides 38 cooperate with the irrigation unit 20 to maintain proper positioning, calibration and/or orientation of the irrigation unit 20 within the irrigation region 30, as described in greater detail below. With this design, the irrigation unit 20 can more accurately deliver irrigation fluid 19 to specific subregions 34 in a manner that reduces irrigation in unwanted areas. In the embodiment illustrated in FIG. 1D, the irrigation region 30 includes three spaced apart alignment guides 38 that are radially positioned relative to the irrigation unit 20, although the number and positioning of the alignment guides 38 can vary. For example, a single alignment guide 38 can be used in conjunction with each irrigation unit 20. Alternatively, two alignment guides 38 or greater than three alignment guides 38 can be used. One or more alignments guides 38 can be positioned within the irrigation region 30 as illustrated in FIG. 1D, or can be positioned outside of the irrigation region 30. Further, the alignment guides 38 can be fixedly positioned in the ground so that they are flush with, or below the surface of the ground. In one embodiment, the alignment guide(s) 38 for one irrigation region 30 can be positioned on an irrigation unit 20 of another irrigation region 30. Alternatively, the alignment guides 38 can be positioned so that they are above the surface of the ground. For example, one or more of the alignment guides 38 can be suspended above the ground on the trunk of a tree, or on any substantially immovable structure that is positioned on the golf hole 14. Further, the shape and size of the alignment guides 38 can vary depending upon the design requirements of the irrigation system 10, the irrigation unit 20 and the golf course 12. In one embodiment, the alignment guides 38 for a specific irrigation region 30 can each be positioned along the perimeter of the irrigation region 30. Alternatively, the alignment guides 38 can be positioned within the perimeter of the irrigation region 30. For example, in the embodiment illustrated in FIG. 1D, the alignment guides 38 can be positioned at approximately 80% to 90% of the distance from the irrigation unit 20 toward the perimeter of the irrigation region 30. Alternatively, the alignment guides 38 can be positioned any other distance from the irrigation unit 20. Further, the three alignment guides 38 can be positioned at approximately 120 degree angles (or any other suitable angles) from each other relative to the irrigation unit 20 so that the alignment guides 38 form a triangle that surrounds the irrigation unit 20. It is recognized that FIG. 1D represents only one of any number of possible configurations of the alignment guides 38 for one of the irrigation regions 30, and that the number and position of alignment guides 38 can vary widely. For instance, the alignment guides 38 can form another type of polygon that either surrounds or does not surround the irrigation unit 20. In one embodiment, each alignment guide 38 is formed from a heat-absorbing and/or heat-emitting material. For instance, the alignment guide 38 can be formed from a material that emits a different amount of heat than the immediately surrounding area. In one embodiment, the alignment guide emits a greater amount of heat than the area that surrounds the alignment guide 38. Alternately, the alignment guide 38 can be formed from a material that absorbs a different wavelength of light than the immediately surrounding area. The alignment guide 38 can be formed at least in part from plastics, epoxy resins, metals, composite materials, magnetic materials or any other suitable materials. FIG. 1E is another embodiment of a portion of a golf hole 14E. In this embodiment, the irrigation units 20E are each positioned within a corresponding irrigation region 30E that is substantially hexagonal in shape. In the embodiment illustrated in FIG. 1E, the hexagonally-shaped irrigation regions 30E are arranged in a honeycomb pattern to increase the total area that is serviced by the irrigation units 20E on the golf hole 14E. However, it is recognized that the irrigation regions 30E can be arranged in any suitable configuration. Moreover, the size of each irrigation region 30E can vary depending upon the design of the irrigation units 20E and the overall topography of the golf course 12. Furthermore, the positioning of the irrigation unit 20E within the irrigation region 30E can vary, as illustrated in FIG. 1E. For example, the irrigation unit 20E can be centrally positioned within the irrigation region 30E, or the irrigation unit 20E can be off-center within the irrigation region 30E. FIG. 1F is a detailed top plan view of a representative irrigation region 30E from the golf hole 14E illustrated in FIG. 1E. In this example, the irrigation region 30E includes the irrigation unit 20E. In one embodiment of the irrigation system 10, the irrigation region 30E is divided into a plurality of substantially identical, triangular-shaped subregions 34E. The size, number and configuration of the subregions 34E can vary depending upon the irrigation requirements of the golf course 12, the configuration and size of the irrigation regions 30E, and the overall topography within the irrigation region 30E, as examples. In the embodiment illustrated in FIG. 1F, the irrigation region 30E includes 216 subregions 34E, although this number is illustrated as a representative example only. In alternative embodiments, the hexagonal irrigation region 30E can be divided into square or rectangular subregions 34 (illustrated in FIG. 1D), for example. In still another alternative embodiment, the irrigation region 30 can be circular, with the subregions 34 each having a wedge-shaped configuration. The design of the irrigation unit 20 and the components of the irrigation unit 20 can be varied. One or more of the irrigation units 20 illustrated in FIG. 1A can have the features of the irrigation units 20 described herein. In one embodiment, the irrigation unit 20 can accurately and precisely irrigate each subregion 34 in the irrigation region 30 to the extent required. Additionally, the irrigation unit 20 can measure, monitor, and/or record (i) an irrigation fluid 19 temperature, (ii) an air temperature near the irrigation unit 20, (iii) a surface temperature of the individual subregions 34, (iv) the relative humidity near the irrigation unit 20, (v) the wind speed near the irrigation unit 20, (vi) the ambient light near the irrigation unit 20, (vii) an irrigation start time for the irrigation unit 20, (viii) an irrigation stop time for the irrigation unit 20, (ix) an amount of irrigation fluid utilized by the irrigation unit 20, and/or (x) a color of ground and/or ground covering at each individual subregion 34. Further, the irrigation unit 20 can self-test the positioning of the irrigation unit 20 and/or self-test the components of the irrigation unit 20. FIG. 2A is a perspective view of one embodiment of the irrigation unit 20. In this embodiment, the irrigation unit 20 is retractable and includes a unit housing 200 having a first section 202, a second section 204, and a third section 206. Alternatively, the unit housing 200 can include more than three or less than three sections. For example, the unit housing 200 can be a unit that does not retract. In FIG. 2A, the irrigation unit 20 is illustrated in the retracted position. In this position, the third section 206 is retracted into the second section 204, and the second and third sections 204, 206 are retracted into the first section 202. With this design, the irrigation unit 20 can be positioned in the ground so that in the retracted position, the entire irrigation unit 20 is at, near or below the surface of the ground. FIG. 2B is a perspective view of the irrigation unit 20 in the extended position with the second section 204 extended above the first section 202, and the third section 206 extended above the second section 204. In this embodiment, (i) the first section 202 includes a generally rectangular box-shaped first frame 208, an opening 210 for receiving the second section 206 and a water inlet 212 that is in fluid communication with the fluid source 18, (ii) the second section 204 includes a generally annular tube-shaped second frame 214, and (iii) the third section 206 includes a generally annular tube-shaped side 216, a generally disk-shaped top 218, and a nozzle 220. In this embodiment, the third section 206 is sized and shaped to fit into the second section 204, and the second section 204 is sized and shaped to fit into the first section 202. The height of the irrigation unit 20 in the extended position and the size of each section 202, 204, 206 can be designed to meet the requirements of the irrigation system 10 (illustrated in FIG. 1A). The first frame 208, the second frame 214, the side 216, and the top 218 can be made of plastic or another type of durable material. In one embodiment, the joints between one or more of the sections 202, 204, 206 are sealed to inhibit water, dirt, and/or other contaminants from entering into the components inside the sections 202, 204, 206. Further, the top 218 can be substantially flat, or can have a convex shape to inhibit collection of irrigation fluid or rainwater, for example, on the top 218. FIG. 2C is a top plan view of the irrigation unit 20, including the first, second, and third sections 202, 204, 206. FIG. 2D is a cut-away view of the first section 202 of the irrigation unit 20. In this embodiment, the irrigation unit 20 includes a plurality of electronic components 221. In one embodiment, the irrigation unit 20 includes (i) a power storage unit 222, (ii) an electronic valve 224, (iii) a flow sensor 226, (iv) a first pressure sensor 228A and/or a second pressure sensor 228B, (v) a unit power source 230, (vi) a fluid temperature sensor 232, (vii) a flexible fluid conduit 234, (viii) a section mover 236, (ix) a section rotator 238, and (x) a unit control system 240. In this embodiment, these components are positioned in the first section 202. Alternatively, one or more of these components can be positioned in another section 204, 206 or in another location. It should be noted that not all of these components are necessary. For example, the auxiliary power source 24 (illustrated in FIG. 1A) can be used instead of the unit power source 230. Further, the orientation and/or positioning of these components can be changed. In one embodiment, one or more of the sensors provided herein generates electronic data that relates to one or more parameters of the irrigation fluid 20, and/or one or more parameters of the surrounding environment. The power storage unit 222 stores electrical energy so that the electronic components of the irrigation unit 20 can function if the unit power source 230 is not providing power. In one embodiment, the power storage unit 222 directly transfers electrical energy to one or more of the electronic components of the irrigation unit 20. In one embodiment, the power storage unit 222 only transfers electrical power to the irrigation unit 20. Non-exclusive examples of a suitable power storage unit 222 include one or more capacitors and/or batteries. The power storage unit 222 is in electrical communication with the unit control system 240 and some of the other components of the irrigation unit 20. In one embodiment, the power storage unit 222 is recharged by the unit power source 230. In one embodiment, the power storage unit 222 is positioned within the housing 200 and is secured directly or indirectly to the housing 200. In an alternative embodiment, the power storage unit 222 is positioned near and outside the housing 200. In alternative, non-exclusive embodiments, for example, the power storage unit 222 can be within approximately 1, 5, 10, 50, 100 or 1000 yards of the housing 200. The electronic valve 224 is used to turn flow of the irrigation fluid 19 on and off, control the rate of the flow and/or pressure of the irrigation fluid 19 that is delivered to the nozzle 220 (illustrated in FIG. 2B) from the water inlet 212. One example of an electronic valve 224 includes a valve 242A, and a valve mover 242B that precisely moves and positions the valve 242A. The valve 242A can be a gate valve, ball valve or another type of valve, and the valve mover 242B can be a solenoid or another type of actuator. In this embodiment, the valve mover 242B is electrically controlled by the unit control system 240 to selectively adjust the flow and/or pressure of the irrigation fluid 19 to the nozzle 220. In the embodiment illustrated in FIG. 2D, the electronic valve 224 is in fluid communication with the water input 212 and the flow sensor 226. As alternative examples, the electronic valve 224 can be selectively and alternatively controlled so that the flow of the irrigation fluid 19 from the water input 212 to the nozzle 220 can be completely on, completely off, or 10, 20, 30, 40, 50, 60, 70, 80, 90 or 95 percent of the flow from the water input 212 if the electronic valve 224 was not present. Stated another way, the electronic valve 224 can be selectively and alternatively controlled so that the valve 242A is completely open, completely closed, or 10, 20, 30, 40, 50, 60, 70, 80, 90 or 95 percent open or any percentage open. The flow sensor 226 measures the flow of the irrigation fluid 19 to the nozzle 220. Suitable flow sensors 226 include a flow meter or turbine wheel with an electronic counter. The first pressure sensor 228A measures the pressure of the irrigation fluid 19 that is being delivered to the irrigation unit 20 and the second pressure sensor 228B measures the pressure of the irrigation fluid 19 that is being delivered to the nozzle 220. Suitable pressure sensors 228A, 228B include a pressure gauge, electrical compression piles or a pressure changing transducer. The unit power source 230 generates electrical energy, provides electrical energy to the electronic components 221 of the irrigation unit 20, is in electrical communication with the electronic components 221 of the irrigation unit 20, and/or charges the power storage unit 222. Further, the unit power source 230 can directly transfer electrical energy to one or more of the electronic components 221 of the irrigation unit 20. In one embodiment, the unit power source 230 only transfers electrical power to the electronic components 221 of the irrigation unit 20. In one embodiment, the unit power source 230 is a turbine type generator 244A that includes a turbine 244B that rotates a rotor 244C relative to a stator 244D to generate electrical energy. In one embodiment, the turbine 244B is in fluid communication with at least a portion of the irrigation fluid 19 that is being delivered to the nozzle 220. With this design, flow of the irrigation fluid 19 causes the turbine 244B to rotate and power to be generated. In alternative embodiments, the turbine 244B can include one or more fan blades, spline blades, or a squirrel cage fan that is rotated. In one embodiment, the unit power source 230 can include an electronic voltage regulator (not shown) that regulates the voltage generated by the unit power source 230. Alternatively, the unit power source 230 can include another type of power generator. For example, FIG. 2E illustrates a top plan view of another embodiment of an irrigation unit 20E that includes an alternative example of a unit power source 230E. More specifically, in this embodiment, the unit power source 230E is a solar type generator that includes a solar panel 244E. In this embodiment, the solar panel 244E is mounted on the top of the first section 202. Alternatively, the solar panel 244E can be mounted on another area of the irrigation unit 20E or near the irrigation unit 20E. Alternatively, the unit power source 230 can include another type of generator, such as an electrolysis unit, a wind type generator, or a fuel cell. Still alternatively, the irrigation unit 20 can be designed without the unit power source 230 and the irrigation unit 20 can be electrically connected to the auxiliary power source 24 (illustrated in FIG. 1A) with one or more power lines. In one embodiment, the unit power source 230 is positioned within the housing 200 and is secured directly or indirectly to the housing 200. In an alternative embodiment, the unit power source 230 is positioned near and outside the housing 200. In alternative, non-exclusive embodiments, for example, the unit power source 230 can be within approximately 1, 5, 10, 50, 100 or 1000 yards of the housing 200. In an alternative embodiment, power is transferred to one or more irrigation units 20 from the auxiliary power source 24 (illustrated in FIG. 1A). For example, one or more of the irrigation units 20 can be electrically connected to the auxiliary power source 24 with standard electrical lines. Alternatively, one or more of the irrigation units 20 can be electrically connected to the auxiliary power source 24 via the irrigation lines 32. In this embodiment, power is transferred from the auxiliary power source 24 through the irrigation fluid 19 in the irrigation lines 32. Referring back to FIG. 2D, the fluid temperature sensor 232 measures the temperature of the irrigation fluid 19 that is delivered to the nozzle 220. Suitable fluid temperature sensors 232 include a thermistor or other electronic devices that change resistance or capacitance with changes of temperature. The flexible fluid conduit 234 connects the water input 212 in fluid communication with the nozzle 220 and allows the nozzle 220 to be moved up and down and rotated. Suitable fluid conduits 234 include a rubber tube or another type of flexible conduit. The section mover 236 moves the second section 204 (illustrated in FIG. 2B) and/or the third section 206 up and down vertically along a unit longitudinal axis 246 (along the Z axis) relative to the first section 202 between the retracted position and the extended position. The section mover 236 can include one or more movers, such as rotary motors, voice coil motors, linear motors utilizing a Lorentz-type force to generate drive force, electromagnetic movers, planar motors, or some other force movers. In another embodiment, the second section 204 and/or the third section 206 can move up and down using irrigation fluid pressure. The section rotator 238 rotates the third section 206 and/or the nozzle 220 about the unit longitudinal axis 246 (about the Z axis) relative to the first section 202. The section rotator 238 can include one or more movers, such as rotary motors, voice coil motors, linear motors utilizing a Lorentz force to generate drive force, electromagnetic movers, planar motors, or some other force movers. The unit control system 240 is in electrical communication with many of the components of the irrigation unit 20 and controls many of the components of the irrigation unit 20. In one embodiment, the unit control system 240 includes a printed circuit board 240A, an electronic processor 240B, and/or a data storage device 240C. The electronic processor 240B processes electronic data and can include one or more conventional CPU's. In one embodiment, the electronic processor 240B is capable of high volume processing and database searches. The data storage device 240C stores electronic data and algorithms for controlling operation of the irrigation unit 20 as described below. The data storage device 240C can include one or more magnetic disk drives, optical storage units, random access memory (RAM), read only memory (ROM), electronically alterable read only memory (EAROM), and/or flash memory, as non-exclusive examples. In one embodiment, the unit control system 240 can receive and store information from (i) the flow sensor 226 regarding flow of the irrigation fluid, (ii) the fluid temperature sensor 232 regarding the temperature of the irrigation fluid 19, and (iii) the pressure sensors 228A, 228B regarding the pressure of the irrigation fluid 19. Additionally, the unit control system 240 can receive and store information from other components of the irrigation unit 20 as described below. Alternately, for example, one or more of these components can provide the information directly to the main control system 22 (illustrated in FIG. 1A). Moreover, for example, the unit control system 240 can control (i) the electronic valve 224 to precisely control the flow rate and/or pressure of the irrigation fluid 19 to the nozzle 220, (ii) the section mover 236 to precisely control the position of the second and/or third sections 204, 204, along the Z axis and the position of the nozzle 220 along the Z axis, and/or (iii) the section rotator 238 to precisely control the rotational position of the second and third sections 204, 206, about the Z axis and the rotational position of the nozzle 220 about the Z axis, the X axis and/or the Y axis. With this design, the nozzle 220 can effectively oscillate back and forth, and up and down relative to the irrigation region 30. Additionally, the unit control system 240 can control other components of the irrigation unit 20 as described below. Alternately, for example, one or more of these components can be controlled directly or indirectly by the main control system 22. In one embodiment, the unit control system 240 is in electrical communication with the main control system 22. For example, the unit control system 240 can communicate with the main control system 22 and transfer data from the irrigation unit 20 to the main control system 22 on a periodic basis or continuous basis. For example, the unit control system 240 can communicate with the main control system 22 and can (i) upload data to the main control system 22, (ii) download data from the main control system 22, (iii) download new programming from the main control system 22, (iv) download new firmware from the main control system 22, and/or (v) download new software from the main control system 22, (vi) detect missing or disabled irrigation units 20, and can selectively enable and/or disable one or more irrigation units 20. Additionally, the unit control system 240 can communicate with the main control system 22 if there are problems with the irrigation unit 20 and/or any of the ground coverings in any of the subregions 34. Moreover, delays or breaks in communication between the unit control system 240 and the main control system 22 can signal problems with the irrigation system 10. FIG. 2F is a front plan view of the third section 206 of the irrigation unit 20. In this embodiment, the third section 206 includes (i) a nozzle opening 248, (ii) the nozzle 220, (iii) a first wind speed sensor 250A and/or a second wind speed sensor 250B, (iv) a first light sensor 252A and/or a second light sensor 252B, (v) a first humidity sensor 254A and/or a second humidity sensor 254B, (vi) a first air temperature sensor 256A and/or a second air temperature sensor 256B, (vii) a subregion sensor opening 258, (viii) a subregion sensor 260, and (ix) an electrical interface 261. In this embodiment, one or more of these components are positioned in or on the third section 206. Alternatively, one or more of these components can be positioned in or on another section 202, 204 or in another location. Further, one or more of these components can be positioned flush with the top 218. It should be noted that not all of these components may be necessary for the operation of the irrigation unit 20. The nozzle opening 248 extends through the side 216 of the third section 206, allows the nozzle 220 to be positioned inside the third section 206 and direct the irrigation fluid 19 outside the third section 206, and allows the nozzle 220 to be moved relative to the side 216. The size and shape of the nozzle opening 248 can be varied to suit the movement requirements of the nozzle 220. In FIG. 2F, the nozzle opening 248 is generally rectangular shaped. The nozzle 220 releases and directs the irrigation fluid 19 to the various subregions 34. In one embodiment, the nozzle 220 is generally tubular shaped and includes a nozzle opening 262 that directs a stream of the irrigation fluid at the respective subregion to reduce the amount of evaporation when the air is hot and/or dry. In one embodiment, to obtain an accurate and even distribution of the irrigation fluid 19 to the various subregions 34, the nozzle 220 is oscillated both up and down and sideways, right and left. This allows the stream to evenly cover and distribute the irrigation fluid 19. Alternatively, for example, the nozzle 220 could be designed to have a pulsed stream, a spray or a pulsed spray. Still alternatively, for example, the valve mover 242B can move the valve 242A to achieve a pulsed spray or other spray pattern. In one embodiment, in the extended position, the nozzle 220 is approximately 12 inches above the ground. Alternatively, for example, the nozzle 220 can be more than or less than 12 inches above the ground. The wind speed sensors 250A, 250B measure the wind speed near the irrigation unit 20. In one embodiment, the first wind speed sensor 250A measures wind speed when the irrigation unit 20 is in the extended position and the second wind speed sensor 250B measures wind speed when the irrigation unit 20 is in the retracted position. Suitable wind speed sensors 250A, 250B include a thermistor with a heater. Measuring how fast the thermistor changes resistance can be correlated to wind speed. The light sensors 252A, 252B measure the light near the irrigation unit 20. In one embodiment, the first light sensor 252A measures the light when the irrigation unit 20 is in the extended position and the second light sensor 252B measures the light when the irrigation unit 20 is in the retracted position. Suitable light sensors 252A, 252B include various photo cells and light sensitive electronics sensitive to visible light. The humidity sensors 254A, 254B measure the humidity near the irrigation unit 20. In one embodiment, the first humidity sensor 254A measures the humidity when the irrigation unit 20 is in the extended position and the second humidity sensor 254B measures humidity when the irrigation unit 20 is in the retracted position. Suitable humidity sensors 254A, 254B include a hygrometer and other moisture sensitive electronic devices sensitive to moisture. The air temperature sensors 256A, 256B measure the air temperature near the irrigation unit 20. In one embodiment, the first air temperature sensor 256A measures the air temperature when the irrigation unit 20 is in the extended position and the second air temperature sensor 256A measures the air temperature when the irrigation unit 20 is in the retracted position. Suitable air temperature sensors 256A, 256B include a thermistor or other temperature sensitive electronic devices. The subregion sensor opening 258 extends through the side 216 of the third section 206, allows the subregion sensor 260 to be positioned inside the third section 206 and monitor the subregions 34 outside the third section 206, and allows the subregion sensor 260 to be moved relative to the side 216. The size and shape of the subregion sensor opening 258 can be varied to suit the movement requirements of the subregion sensor 260. In FIG. 2F, the subregion sensor opening 258 is generally rectangular shaped. The subregion sensor 260 monitors the status of one or more of the subregions 34 in the irrigation region 30. In one embodiment, the subregion sensor 260 directly or indirectly measures the temperature at a portion of each subregion 34. In another embodiment, the subregion sensor 260 can be used to directly or indirectly measure the moisture content of a portion of one or more subregions 34. For example, in this embodiment, the subregion sensor 260 can be used in conjunction with one or more other sensors to measure the temperature of a portion of a subregion 34, the humidity and/or the air temperature. This information can then be used in an algorithm to indirectly determine the moisture content of the portion of the subregion 34. Additionally, or alternatively, the subregion sensor 260 can measure or detect the color or other features of the surface covering of each subregion 34. For example, the subregion sensor 260 can determine which subregions 34 have the desired color, e.g. green, and which subregions 24 are turning an undesired color, e.g. brown. In one embodiment, the subregion sensor 260 can include an infrared sensor 260A that receives an infrared signal. In this embodiment, the infrared sensor 260A can be sequentially directed at each individual irrigation subregion 34 to independently receive an infrared signal at each individual irrigation subregion 34 to individually measure the subregion temperature at each subregion 34. Additionally, in one embodiment, the subregion sensor 260 can include a lens 260B that intensifies the light collected by the subregion sensor 260. For example, the lens 260B can be a lenticular or Fresnel type lens that is designed to optimize the IR signal and concentrate it on the IR sensor 260A. Additionally or alternatively, for example, the subregion sensor 260 can include a visible light detector 260C that is sequentially directed at each individual irrigation subregion 34. In this embodiment, the lens 260B can be designed and optimized for the low incidence angle for the visible and infrared wavelengths. In one embodiment, in the extended position, the subregion sensor 260 is approximately 24 inches above the ground. Alternatively, for example, the subregion sensor 260 can be more than or less than 24 inches above the ground. In one embodiment, the lenses and sensors can be coated with a high density non-stick coating 259C (illustrated as shading) such as polytetraflouroethylene to inhibit adhesion of material, such as dirt, chemicals, water minerals, impurities, and deposits to the lenses and sensors. Additionally, referring back to FIG. 2B, the irrigation unit 20 can include a cleaner unit 259U that can be used to clean one or more of the lenses and/or sensors. For example, the cleaner unit 259U can include (i) a nozzle to direct irrigation fluid, water or a cleaning fluid on one or more of the lenses and/or sensors and/or (ii) a material such as cloth or chamois that can wipe one or more of the lenses and/or sensors. The electrical interface 261 allows for an external control system 326 (illustrated in FIG. 3) to interface with the unit control system 240. In one embodiment, the electrical interface 261 is an input jack that is electrically connected to the unit control system 240. In this embodiment, the external control system 326 includes an electrical connector that inputs into the input jack. In another embodiment, for example, the electrical interface 261 can be an electrical receiver/transmitter that interfaces with a receiver/transmitter of the external control system 326 to allow for data transfer within the irrigation system 10 between the systems 326. 240. With these designs, the external control system 326 is either wirelessly, visible light, or invisible light, inductively, or capacitively coupled to the unit control system 240. It should be noted, for example, in an alternative embodiment, that the electrical interface 261 can be mounted on the top edge of the section 202. The unit control system 240 (illustrated in FIG. 2C) is in electrical communication with and receives information from the wind speed sensors 250A, 250B, the light sensors 252A, 252B, the humidity sensors 254A, 254B, the air temperature sensors 256A, 256B, and the subregion sensor 260. Stated another way, the unit control system 240 monitors and stores on a programmable periodic basis, air temperature, humidity, wind speed and visible light with times. Alternately, for example, one or more of these components can provide the information directly or indirectly to the main control system 22 (illustrated in FIG. 1A). Based on the data gathered by the unit control system 240, the unit control system 240 can determine which subregions 34 need irrigation, the best time to irrigate, and the appropriate quantity to irrigate. Additionally, with this information problems with the irrigation unit 20 and/or the ground covering in each subregion 34 can be detected and reported to the main control system 22. In one embodiment, based on the information received by the unit control system 240, the unit control system 240 using algorithms based on the previous data, e.g. recorded air temperature, humidity, wind speed and/or visible light, can determine how much irrigating, if any, needs to be done. FIG. 2G is a cut-away view of one embodiment of the third section 206 of the irrigation unit 20. FIG. 2G illustrates that the irrigation unit 20 includes (i) a nozzle pivot 264 that secures the nozzle 220 to the side 216 of the third section 206 and allows the nozzle 220 to pivot relative to the third section 206, (ii) a sensor pivot 266 that secures the subregion sensor 260 to the side 216 of the third section 206 and allows the subregion sensor 260 to pivot relative to the third section 206, and (iii) a nozzle mover 268 that moves and pivots the nozzle 220 and the subregion sensor 260 relative to the third section 206. The nozzle mover 268 can include one or more movers, such as rotary motors, voice coil motors, actuators, linear motors utilizing a Lorentz-type force to generate drive force, electromagnetic movers, planar motors, or some other force movers. In FIG. 2F, the nozzle mover 268 is coupled with a nozzle linkage 270 to the nozzle 220 and a sensor linkage 272 to the subregion sensor 260. With this design, the nozzle mover 268 concurrently moves both the nozzle 220 and the subregion sensor 260. Alternatively, for example, separate movers (not shown) can be used to individually move the nozzle 220 and the subregion sensor 260. Still alternatively, the nozzle 220 and the subregion sensor 260 can be fixedly attached together and can move together. The unit control system 240 can control the nozzle mover 268 to precisely control the position of the nozzle 220 and the subregion sensor 260. With this design, by controlling the section mover 236 (illustrated in FIG. 2D), the section rotator 238 (illustrated in FIG. 2D), and the nozzle mover 268, the unit control system 240 can individually and selectively direct the subregion sensor 260 at each subregion 34 and receive information from each subregion 34. Further, with this design, by controlling the section mover 236, the section rotator 238 (illustrated in FIG. 2D), and the nozzle mover 268, and the electronic valve 224 (illustrated in FIG. 2D), the unit control system 240 can individually and selectively direct the irrigation fluid 19 from the nozzle 220 at any one or every one of the subregions 34. Alternatively, for example, one or more of these components can be controlled directly or indirectly by the main control system 22. As used herein, the section mover 236, the section rotator 238 and the nozzle mover 268 are individually and/or collectively referred to as a nozzle mover assembly. As provided herein, the nozzle mover assembly can include additional movers to position and move the nozzle 220 and/or the subregion sensor 260. In the embodiment illustrated in FIG. 2G, the irrigation unit also includes a nozzle sensor 276 and a rotation sensor 278. The nozzle sensor 276 can detect the relative positioning of the nozzle 220 about one or more axes. In other words, the nozzle sensor 276 can sense the angle of the nozzle 220 about any axis, and can transmit this information to the unit control system 240. The unit control system 240 can use this information to determine whether the nozzle 220 is properly angularly positioned to irrigate the desired subregion 34. In an alternative embodiment, the position of the nozzle 220 can be determined by monitoring the amount of current (or other power) that has been directed to the nozzle mover assembly, e.g. to move the nozzle 220 from a predetermined starting position. The positioning of the nozzle sensor 276 can be varied depending upon the design requirements of the irrigation unit 20. In this embodiment, the nozzle sensor 276 is positioned in the interior of the third section 206. In an alternative embodiment, the nozzle sensor can be positioned on the nozzle, or in another suitable location. The rotation sensor 278 can detect the rotation of the third section 206, and thus the nozzle 220, relative to the second section 204, the first section 202, the sprinkler housing 200 and/or the irrigation region 30. In other words, the rotation sensor 278 can monitor the 360 degree rotational positioning of the third section 206 to determine whether the third section 206 is properly oriented to deliver irrigation fluid 19 to the desired subregion 34. The rotation sensor 278 transmits this information to the unit control system 240. The unit control system 240 can use this information to determine whether the nozzle 220 is accurately rotationally positioned to irrigate the desired subregion 34. In an alternative embodiment, the position of the third section 206, and thus the rotational position of the nozzle 220, can be determined by monitoring the amount of current (or other power) that has been directed to the section rotator 238, e.g. to move the third section 206 from a predetermined starting position. The positioning of the rotation sensor 278 can be varied depending upon the design requirements of the irrigation unit 20. In this embodiment, the rotation sensor 278 is positioned on the exterior of the third section 206. In an alternative embodiment, the rotation sensor 278 can be positioned in the interior of the third section 206, on the exterior or in the interior of the second section 204, or in another suitable location. With this design, the unit control system 240 accurately (i) controls the movement of the nozzle 220 head up, down or around, (ii) controls the pressure and flow of the irrigation fluid 19 to the nozzle 220, and/or (iii) turns the irrigation fluid 19 on and off, including when the nozzle 220 is directed at sand traps 16F, cart paths 16H, water features 16G, walkways 16J, or other areas where irrigation fluid 19 is not necessarily desired. In this manner, the irrigation unit 20 is able to accurately and individually irrigate each subregion 34 of each irrigation region 30 to the desired level, and in the required order. This can result in virtually no overlap between adjacent irrigation units 20, and therefore, little or no wasted irrigation fluid 19, thereby saving costs for both irrigation fluid 19 and electricity to pump the irrigation fluid 19. FIG. 2H is a cut-away view of the third section 206 of the irrigation unit 20. FIG. 2H illustrates that in one embodiment, the subregion sensor 260 is offset from the nozzle 220. The amount of offset can vary. For example, the subregion sensor 260 can be offset approximately 90 degrees of the nozzle 220. Alternatively, the offset can be greater or less than 0 degrees. In FIG. 2H, the nozzle 220 pivots near the end of the nozzle 220. Alternatively, for example, the nozzle 220 can pivot at the center of the nozzle 220 or about another area. FIG. 21 is a perspective view of another embodiment of the irrigation unit 20I. In this embodiment, the irrigation unit 20I includes a protective cover 274 that distributes the load and protects the irrigation unit 20I. In FIG. 21, the protective cover 274 is a flat or slightly convex plate that is secured to the top of the third section 206. The composition of the protective cover 274 can vary, provided the protective cover is sufficiently rigid to withstand forces from pedestrians, golf carts and other vehicles, golf bags, pull carts, tractors, lawnmowers, other landscaping equipment or any other forces that could possibly damage the irrigation units 20I. FIG. 2J is a perspective view of still another embodiment of the irrigation unit 20J. In this embodiment, the protective cover 274J is slightly curved or convex shaped so that water and other debris fall more easily off the cover 274J. With this design, the sensors 250B, 252B, 254B, 256B are less likely to be covered. Still alternatively, the protective cover can have another shape such as slightly pitched, slightly concave, arched, or slightly inclined. Referring back to FIG. 1D, in one embodiment, at one or more times, e.g. at programmable time intervals, the irrigation unit 20 also verifies the relative positioning of the irrigation unit 20 and adjusts and/or corrects the position of the nozzle 220 (illustrated in FIG. 2B) as needed. If the position cannot be corrected by the irrigation unit 20, a signal can be sent to the main control system 22 so that the irrigation unit 20 is manually repositioned or otherwise recalibrated or fixed. Thus, if the irrigation unit 20 is damaged or moved, it can correct the problem or notify the main control system 22 via the unit control system 240. In one embodiment, the subregion sensor 260 is utilized to determine if the nozzle 220 is directing the irrigation fluid 19 to the appropriate desired area. For example, the alignment guides 38 (illustrated in FIG. 1D) for a particular irrigation region 30 are monitored with the subregion sensor 260 prior to or during irrigation to determine if the nozzle 220 is being correctly positioned to irrigate these positions. In FIG. 1D, the alignment guides 38 are located approximately 120 degrees apart at about 80% to 90% of the distance of the irrigation distribution throw. The subregion sensor 260 can locate and monitor these positions to make certain that the positioning of the nozzle 220 is true and accurate. In one embodiment, the unit control system 240 is programmed to know where these alignment guides 38 are located within the irrigation region 30. On a periodic or continual basis, the subregion sensor 260 can locate one or more of the alignment guides 38 for the specific irrigation region 30 based on information that can be initially programmed into the unit control system 240. Stated another way, the unit control system 240 can cause the subregion sensor 260 to be positioned to detect heat or a specific wavelength of light from the alignment guides 38 in a specific direction based on an initial positioning of the alignment guides 38 relative to a portion of the irrigation unit 20, such as the subregion sensor 260, for example. In another embodiment, the subregion sensor 260 can detect a particular physical pattern or signature that is imprinted or impregnated on the alignment guide 38. If, however, the irrigation unit 20 moves from its initial orientation, i.e. from impact with a golf cart, vandalism, or any other unwanted movement, and the subregion sensor 260 is unable to detect one of the alignment guides 38 at its initial position, the unit control system 240 can cause one or more of the actuators to oscillate the subregion sensor 260 up and down, side to side, or both, until the alignment guide 38 is located by the subregion sensor 260. Once one or more of the alignment guides 38 are located in this manner by the subregion sensor 260, information regarding the extent of the necessary oscillation until such alignment guide(s) 38 were located, i.e. angle, direction and/or distance, is provided by the subregion sensor 260 to the unit control system 240 for processing. The unit control system 240 can then determine the extent to which the irrigation unit 20 has been moved, dislodged, disoriented or the like, from its initial orientation, along or about any axis. Once this extent is determined, the unit control system 240 can adjust the flow rate of irrigation fluid 19 to the nozzle 220 and/or the positioning of the nozzle 220 accordingly, i.e. about or along any axis, so that the coordinates for each subregion 34 in the irrigation region 30 are effectively recalibrated and accurate irrigation is maintained. Stated another way, with the extent of misalignment determined, the unit control system 240 can compensate for the misalignment. The irrigation unit 20 can then be automatically or manually reprogrammed to effectively recalibrate the irrigation unit 20 based on its modified orientation relative to the alignment guides 38. With this design, any disruption or offset of irrigation of the irrigation region 30 can be reduced or eliminated despite unwanted movement of the irrigation unit 20 along or about any axis. The way in which the position of the irrigation unit 20 relative to the alignment guides 38 is determined can vary. For example, the subregion sensor 260 can detect the heat, light or color to locate one or more alignment guides 38. Alternatively, for example, the subregion sensor 260 can send a signal that is reflected off of the alignment guides 38 to locate one or more alignment guides 38. Still alternatively, for example, one or more of the alignment guides 38 can send a signal that is received by the subregion sensor 260 to locate the alignment guides 38, or one or more of the alignment guides can include a sensor that determines the position of the irrigation unit 20. FIG. 3 illustrates that the irrigation units 20 can be electrically connected and/or coupled to the main control system 22. It should be noted that one or more of the functions performed by the main control system 22 and described herein can be performed by one or more of the unit control systems 240 (illustrated in FIG. 2D). Further, one or more of the functions performed by the unit control systems 240 and described herein can be performed by the main control system 22. The main control system 22 can include a personal computer (PC), or workstation, and can include (i) a central processing unit (CPU) 310, (ii) one or more forms of memory 312, 314 such as EPROM, EAROM, magnetic or optical storage drives, (iii) one or more peripheral units such as a keyboard 316 and a display 318, (iv) a data encoder/decoder unit 320 which provides two-way communication between the irrigation units 20 and the main control system 22, and/or (v) an internal bus 301 that electrically connects one or more of the components of the main control system 22. The data encoder/decoder unit 320 encodes data on the internal bus 301 under control of the CPU 310. The encoded data is then transmitted over the data line 28 to the irrigation unit(s) 20. Incoming data from the irrigation units 20 is decoded by the data encoder/decoder unit 320 and used by the CPU 310 and stored in one or more of the memory units 312, 314. Alternatively, for example, the main control system 22 can communicate with the irrigation units 20 wirelessly using the irrigation fluid 19 flowing through the irrigation lines 32. In this case, for example, the encoded signals are transmitted by electromagnetic waves, DC/AC signal, visible or invisible light, or RF signals through the irrigation fluid 19 in the irrigation lines 32. The encoded signal is sent from an antenna, or aerial 322, located in the irrigation line 32, and electrically connected to the encoder/decoder 320 in proximity to the main control system 22, and this signal is transmitted through the irrigation fluid 19 flowing in the irrigation line 32. The signal is then received at the irrigation unit(s) 20 by another antenna 324 electrically connected to the unit control system 240 and located in the irrigation line 32 in proximity to the irrigation unit(s) 20. Additional connections (not shown) can be located in irrigation lines 32 and the ground proximate the main control system 22 and each irrigation unit 20, for transmitting and receiving the encoded signals via the earth and in combination with transmission via the irrigation fluid 19. In the case of transmission of the encoded signals using electromagnetic waves or DC/AC signal, a ground to earth at the irrigation unit 20 and at the main control system 22 can be used. At the irrigation unit 20, the ground to earth can consist of a ground spike 328 (only one ground spike 328 is illustrated in FIG. 3) that is implanted into the earth near the irrigation unit 20, with a wire 330 connecting the ground spike to the irrigation unit 20. In another embodiment, the irrigation unit 20 can have bare metal wires (not shown) that extend into the earth, or the irrigation unit 20 can include a metallic bottom (not shown) that directly contacts the earth. In alternative embodiments, the communication between the main control system 22 and the irrigation units 20 can be accomplished using RF signals through the air, infrared and/or other non-visible light signals, or using fiber optic cables, as non-exclusive examples. Furthermore, each irrigation unit 20 can retransmit a received signal to other irrigation units 20 in the irrigation system 10 to keep the signal strength high in the network. In one embodiment, while different irrigation units 20 receive and retransmit the signal, each irrigation unit 20 can have a unique identifier or serial number (ID). In this design, only the irrigation unit 20 having a predetermined ID will respond to the signal. The main control system 22 monitors and controls the overall operation of the irrigation system 10 based on firmware algorithms stored in magnetic or optical disks, the Read Only Memory unit (ROM) 312, and/or stored in the unit control systems 240. Data and programming information stored at each unit control system 240 can also be stored in the main control system 22. The main control system 22 can troubleshoot problems in the irrigation system 10 and take faulty or otherwise problematic irrigation units 20 off the system until they can be repaired or replaced. In one embodiment, the main control system 22 is additionally used to program or reprogram the irrigation units 20 with upgraded firmware, new irrigation sequences, and/or new irrigation requirements for changes in vegetation or reconfigured irrigation regions 30, as non-exclusive examples. Additionally, in one embodiment, the main control system 22 can control the sequence of the start times for each irrigation unit 20. Furthermore, the main control system 22 can be used to override the set irrigation duration, times, and control the irrigation units 20 to irrigate at other times. In monitoring the operation of the irrigation system 10, the main control system 22 can obtain and store all data collected at and associated with each irrigation unit 20. The main control system 22 compares current and previously received data to provide statistical data and determine whether the irrigation system 10 and/or one or more of the irrigation units 20 are operating properly. For example, the main control system 22 collects data including the quantity of irrigation fluid used for each irrigation unit 20 over time, and the main control system 22 can compare the current usage for a given irrigation unit 20 to past usage amounts. If there is a significant change in usage amounts (e.g. above a threshold percentage) during a particular period in time, this could indicate that a problem exists at that irrigation unit 20 or in the irrigation line 32 leading toward or away from that irrigation unit 20. For example, the main control system 22 can compare the irrigation fluid 19 usage for an irrigation unit 20 against the total system usage amount to determine if there is a potential problem in the irrigation line 32 (e.g. otherwise undetectable breaches in the irrigation line 32) and/or the irrigation unit 20. In other words, the main control system 22 can cooperate with the irrigation units 20 to determine if there are any “invisible” underground irrigation line breaks by comparing total irrigation unit 20 usage with the total irrigation fluid 19 initially delivered to one or more of the irrigation units 20. For example, the irrigation system 10 can perform a static pressure test during non-irrigation times by obtaining a measurement of the irrigation fluid pressure near a fluid meter 330 positioned near a pump station (not shown) or fluid source 18 (illustrated in FIG. 1A), and comparing this measured pressure with the irrigation fluid pressure at the first pressure sensor 228A of one or more of the irrigation units 20. A disparity in pressure above a predetermined threshold percentage from near the fluid meter 330 to the irrigation unit 20 can indicate to the main control system 22 that a problem with a nearby irrigation line 32 exists, or it can be indicative of a problem with the irrigation unit 20 from which the decreased pressure was measured. This type of testing is enabled because of the ability of the irrigation system 10 to pressurize the irrigation lines without actually sending irrigation fluid 19 through the irrigation units 20. Further, the irrigation system 10 can perform a dynamic pressure test by comparing the expected irrigation fluid pressure at one or more irrigation units 20 (taking into account elevation differences between the water source 18 and/or pump station 330 and the irrigation units 20) during an irrigation cycle, and comparing this expected pressure with the actual measured irrigation fluid pressure from the first pressure sensor 228A or the second pressure sensor 228B at the one or more irrigation units 20 during an irrigation cycle. If the expected pressure is a predetermined percentage above the measured pressure, this can be indicative of a breach in the irrigation line 32. By selectively activating certain irrigation units 20, the approximate location of the breached irrigation line can be determined. Any detected potential problem can be indicated on the display 318 of the main control system 22. With this design, a substantial amount of irrigation fluid can be saved as a result of detecting a leak when such leak could otherwise go undetected for an extended period of time. Additionally, the main control system 22 can (i) collect all programming information for each irrigation unit 20, (ii) display all vegetation problems or failures reported by the irrigation units 20, (iii) poll all the irrigation units 20 to make certain they are there and functioning properly, (iv) reprogram any existing or replacement irrigation units 20 with the stored head programming data from the irrigation units 20, (v) reprogram any or all of the irrigation units 20 with new firmware, and/or (vi) reprogram the location(s) of the subregion(s) 34 in one or more irrigation regions 30, change from routine irrigating to new from seed irrigating, etc. In another embodiment, the main control system 22 can control the sequence of start times for the individual irrigation units 20. Moreover, the manufacturer can be able to poll the main control system 22 and download all data with a modem. The data can be used by the manufacturer to enhance the algorithms and add new features. Further, the main control system 22 can be utilized to determine if the irrigation units 20 are all operational, because the main control system 22 is in periodic and/or continuous communication with the irrigation units 20. For example, each irrigation unit 20 can be programmed to perform a self-test prior to irrigating its respective irrigation region 30. If there is a problem with the self-test, the unit control system 240 can communicate a fault to the main control system 22. In one embodiment, the self-test can include determining whether the irrigation unit 20 is properly oriented relative to the alignment guides 38. Other self-testing functions can include taking humidity and/or temperature readings to determine proper functioning of one or more of the sensors, and checking proper functioning of the data storage device (RAM unit, ROM unit, EAROM), the power storage unit (battery or capacitor storage), the unit power source, communications, irrigation fluid pressure, etc. In one embodiment, the data from each irrigation unit 20 is compared with surrounding irrigation units 20 to determine whether a specific irrigation unit 20 is functioning consistently with other nearby irrigation units 20. For instance, in the event that one irrigation unit 20 is generating data indicating a greater than 5% disparity from one or more surrounding irrigation units 20, then main control system 22 can determine that a problem with the irrigation unit 20 may exist. This threshold percentage can vary depending upon the desired sensitivity of the system or the type of data being analyzed, and can be greater or less than 5%, i.e. 1%, 2%, 10%, 20%, 30%, 50%, 75%, 100%, or some other appropriate percentage. The main control system 22 can attempt a repair of the irrigation unit 20 by sending a reset command to the unit control system 240, or by reprogramming the unit control system 240, after which the irrigation unit 20 can perform the self-test again. If no potential problem is indicated, then the irrigation unit 20 can proceed with the newly programmed irrigation plan. Alternatively, if there still is a potential problem, the main control system 22 can turn off the irrigation unit 20 and flag it for repair. In one embodiment, if an irrigation unit 20 needs to be replaced, the replacement irrigation unit 20 can be installed and programmed very efficiently since the information for each irrigation unit 20 is stored in the main control system 22. Turning back to the control of the irrigation units 20, the irrigation unit 20 is controlled by one or more algorithms that are stored in and use information associated with each irrigation unit 20. The algorithms and initial information can be programmed into the unit control system 240 of the irrigation units 20 or can be downloaded from the main control system 22 or downloaded through the electrical interface 261. Initial information for each irrigation unit 20 can include (i) specific identification indicia, such as a serial number or ID, for the irrigation unit 20, (ii) topographical information, such as the slope and elevation of the region 30 and each subregion 34 within the irrigation region 30 for that irrigation unit 20, (iii) the type of grass or vegetation within each irrigation region 30 and subregion 34, and/or (iv) information defining the configuration or shape of the irrigation region 30 to be irrigated by the respective irrigation unit 20. The algorithms can be utilized to control the irrigation sequences for each respective irrigation unit 20. After the irrigation sequences are determined for each irrigation unit 20, a priority for when the irrigation unit 20 is to perform its irrigation sequence is established and assigned to each irrigation unit 20. In one embodiment, the algorithms and initial information for each irrigation unit 20 is programmed into the unit control system 240 for each irrigation unit 20 by an operator. In one embodiment, the initial information is inputted using a portable computing device 326 that is directly, wirelessly, inductively or capacitively coupled, or coupled using visible or invisible light, to the electronics of the unit control system 240 for one or more of the irrigation units 20 and/or the main control system 22. For example, the portable computing device 326 can be in communication with the electrical interface 261 of one or more of the irrigation units 20. In one embodiment, the portable computing device 326 is wirelessly connected to the irrigation unit 20 and/or the main control system 22 during programming of the irrigation units 20. With this connection, all of the irrigation units 20 in the system 10 can be programmed. Alternatively, in another embodiment, the algorithms and initial information can be input into the main control system 22 using the keyboard 318 or the portable computing device 326. The portable computing device 326 can be electrically connected to the irrigation unit 20 via the electrical interface 261. In one embodiment, the portable computing device 326 includes a display screen that graphically displays with adjustable size the irrigation regions 30 and/or subregions 34 of the golf course 12. For example, the display screen can display one of the subregions 34 in detail. The position of the irrigation unit 20 in the irrigation subregion 34 and the serial number of the irrigation unit 20 can be input into the irrigation unit 20. Subsequently, the portable computing device 326 can control the unit control system 240 to use the subregion sensor 260 to locate the alignment guides 38 for the subregions 34. Once the irrigation unit 20 locates the alignment guides 38, the operator can control the irrigation unit 20 to irrigate the alignment guides 38. If necessary, the software of the irrigation unit 20 is adjusted so that the irrigation unit 20 accurately irrigates the alignment guides 38. This allows the irrigation unit 20 to accurately irrigate other areas of the subregion 34. Additionally, with the subregion 34 displayed on the portable computing device 326, the operator can enter the features of each portion of the subregion 34. For example, the operator can enter the vegetation, trees, greens, fairways, cart path, water features, etc., of the specific subregion 34. In one embodiment, the irrigation unit 20 would be programmed not to irrigate the cart path. Another example would include programming the irrigation unit 20 to distribute more irrigation fluid 19 in a grass area than in a shrub area. Once all of the subregions 34 in a specific irrigation region 30 have been programmed into the irrigation unit 20, the irrigation unit 20 can be programmed for which subregions 34 of the irrigation region 30 get irrigated first—and for how long—to prevent runoff. In one example, a first subregion 34 can require approximately 15 minutes of irrigating. However, runoff occurs after five minutes. In this example, the irrigation unit 20 would be programmed to irrigate the first subregion 34 for five minutes. After five minutes of irrigating, the irrigation unit 20 starts irrigating a second subregion 34. Subsequently, the irrigation unit 20 returns back to irrigate the first subregion 34 for another five minutes. This sequence is repeated until each subregion 34 is adequately irrigated. The sequencing would be continued until all of the subregions 34 have been programmed into the irrigation unit 20. Next, the priority of when each irrigation unit 20 starts would be entered by the operator. In one embodiment, the irrigation units 20 would go on by themselves at the start of the designated time if the irrigation unit 20 determined that there was sufficient pressure of the irrigation fluid 19 for the irrigation unit 20 to operate. In one embodiment, for a golf course 12, the irrigating start times and end times would be programmed in so as not to irrigate while golfers are in the vicinity, if possible. Turning now to the automated operation of the irrigation system 10, as set forth above, different irrigating sequences can be carried out by one or more algorithms which are dependent on information specific to, and gathered by, each irrigation unit 20. The main control system 22 and unit control systems 240 of the irrigation system 10 of the present invention can use different types of algorithms to control the irrigating sequences performed by the individual irrigation units 20. In one embodiment, the type of algorithm employed in the irrigation system 10 can depend on real-time, changing parameters. Another embodiment utilizes a second type of algorithm that is set and does not change on its own. Instead, this type of algorithm may be changed, or reprogrammed, by the main control system 22, or manually by a system operator using the keyboard 316, the portable computing device 326 or another suitable method. In one embodiment, both the main control system 22 and the unit control systems 240 use the algorithms that depend on changing parameters. Alternatively, the unit control systems 240 can use the set algorithms, while the main control system 22 uses an algorithm that depends on changing parameters. In general, the unit control systems 240 can utilize algorithms to determine an irrigation sequence for the subregions 34 within the irrigation region 30 of a corresponding irrigation unit 20. In contrast, the main control system 22 can control the overall operation, timing and sequence of the irrigation units 20 in an area of the golf course 12 (or other land area) such as a single golf hole 14, a portion of a golf hole 14, a portion of the golf course 12, or the entire golf course 12, as non-exclusive examples. Alternatively, the main control system 22 can also control the irrigation sequence for irrigation of the subregions 34 within one or more specific irrigation regions 30. Referring first to the algorithms used by the unit control systems 240, in one embodiment, the unit control system 240 can be programmed to irrigate its respective irrigation region 30 in the following sequence: irrigate the subregions 34 with the highest elevations first, then irrigate the surrounding subregions 34 of these first-irrigated subregions 34, and then irrigate progressively lower elevation subregions 34. The algorithm used to perform the irrigation sequence could also take into consideration the slope of the subregions 34 in determining the quantity and/or flow rate of irrigation fluid 19 that is applied to the different subregions 34. For example, when irrigating the subregions 34 surrounding the highest elevations, the amount of irrigation fluid 19 used would be reduced by a predetermined percentage to compensate for an expected quantity of irrigation fluid 19 runoff from the higher elevation subregions 34. The percentage reduced can vary, and can be dependent upon the slope of the surrounding subregions 34, for example, such that the greater the slope, the greater the reduction of irrigation fluid 19 output for the surrounding, lower-lying subregions 34. Other factors that the algorithm can take into account are, for example, the type of vegetation or grass in each subregion 34, or the fact that the subregion 34 contains a feature that does not require irrigation fluid 19, such as a cart path 16H, sand trap 16F, water feature 16G, or other features that do not require irrigation. Thus, the unit control system 240 can determine that the subregions 34 within a specific irrigation region 30 require a disparate amount of irrigation fluid 19, and that certain subregions 34 do not require any irrigation fluid 19. With this design, the irrigation unit 20 can precisely control the quantity and/or flow rate of irrigation fluid 19 applied to different and/or adjacent subregions 34. For example, in alternative embodiments, the unit control system 240 can determine that approximately 5%, 10%, 25%, 50%, 75% or 100% greater irrigation fluid 19 is required as between different and/or adjacent subregions 34. Alternatively, some other percentage difference between different and/or adjacent subregions 34 may be determined by the unit control system 240. The algorithm above is one of the set type of algorithms, since the sequence in which the subregions 34 are watered does not normally change. In an alternative embodiment the irrigating sequence could be based on an algorithm which depends on a real-time parameter such as the color of the grass or vegetation in each subregion 34. In this example, the algorithm can utilize sensor readings on the color in each subregion 34, and the irrigation sequence is carried out from lightest to darkest subregions 34, or from darkest to lightest. In still other embodiments, the above described algorithms can also take into account weather factors, such as, for example, the temperature, humidity, barometric pressure, wind direction and speed, in determining the amount of irrigation fluid 19 to use, once the sequence is determined. Additionally, since the unit control systems 240 can obtain the various weather and vegetation readings in real-time, the algorithms can compare the current reading with past readings to determine whether any adjustments need to be made in the irrigating sequence and/or the amount of irrigation fluid 19 used. Stated another way, the algorithms can take into account a change in the physical condition of one or more subregions 34 within the irrigation region 30 over time. For example, when the irrigation unit 20 is not irrigating, on a predetermined periodic basis, the date, time of day, temperature, amount of visible light, wind speed, humidity, temperature of specific vegetation, color of specific vegetation and/or other relevant parameters within the irrigation region 30 can be measured and stored by the irrigation unit 20. The algorithms stored in the unit control system 240 can use such past historical data along with current data (e.g. past 48 hours or some other suitable preset time period) in order to calculate the amount of irrigation fluid 19 required over time for each subregion 34 in the irrigation region 30. Moreover, the unit control system 240 or the main control system 22 can compare the calculations from a particular irrigation unit 20 over time to detect discrepancies indicative of a problem with the irrigation unit or the vegetation within the irrigation region 30. For instance, if the calculated quantity of irrigation fluid 19 is being applied to a subregion 34, yet the color of the vegetation within the subregion is inconsistent with the desired color within a set period of time, the unit control system 240 can identify a problem. In one embodiment, the amount of irrigation fluid 19 can be steadily adjusted, i.e. increased or decreased over time, as determined by the algorithm(s) programmed into the unit control system 240, in order to achieve the desired color of vegetation. In the event the desired color is not achieved within a specified period of time as determined by the algorithm(s), the particular subregion 34 or irrigation unit 20 can be automatically or manually investigated for potential problems. In this manner, the unit control systems 240 can be considered “smart systems,” since they are continuously learning and adapting the irrigation sequence based on previous irrigation fluid 19 usage data including times, quantity, and irrigation regions 30, which is stored in the irrigation units 20. Further, since the unit control systems 240 are in communication with the main control system 22, the algorithms executed at the unit control systems 240 can request higher priority or additional irrigation fluid 19 from the main control unit 22 if the real-time measured conditions indicate that the algorithm calculations will not provide adequate irrigation for the irrigation region 30. Moreover, in one embodiment, the unit control system 240 can reestablish an irrigation sequence anew for its respective irrigation unit 20 on a periodic basis. For example, the unit control system 240 can reevaluate and recalculate an appropriate irrigation sequence at least approximately once every 24 hours. In alternative embodiments, the unit control system 240 can determine an appropriate irrigation sequence more or less often than one every 24 hours. In the above examples, the priority or sequence of when each irrigation unit 20 is operated can be programmed from the main control system 22 as determined by a system operator. For example, the irrigation units 20 can be grouped based on the type of region of the golf course 12, such as the fairways 16C, the greens 16E, and/or other areas. The different groups are assigned priority levels by the operator and programmed by the main control system 22 to the units 20. The main control system 22 would control the starting times for each group to begin its irrigation sequence. In one embodiment, the irrigating times would be times when the golf course 12 is not in use. At the programmed starting time, the irrigation units 20 in each group would start its programmed irrigating sequence if it is determined that there's sufficient pressure of irrigation fluid 19 to begin irrigation. However, these set times can be overridden if it is necessary to provide additional irrigation times due to extreme weather conditions, such as high temperatures, low humidity, etc. This can be done manually by a system operator, or alternatively, the unit control systems 240 can be programmed to run the algorithms whenever their sensors record information that the temperature or humidity on the golf course 12 has reached a specific threshold value. In this case, the unit control system 240 can communicate with the main control system 22, which can then decide whether or not the previously unscheduled irrigating should be performed. In another embodiment, the algorithm for irrigating can be dependent upon the following parameters: temperature of the grass or vegetation, relative humidity, color of the grass or vegetation, amount of sunlight, time of day, time of year, irrigating requirements for the type of ground covering, wind conditions, or other suitable parameters. At preprogrammed times, the irrigation unit 20 can measure the temperature, amount of light, wind conditions and humidity at the unit 20, the temperature and/or color of the ground covering in the subregion 34. The unit control system 240 calculates an amount of irrigation fluid 19 necessary for the subregion 34 based on the temperature, amount of light, wind conditions and humidity at the irrigation unit 20, and an amount of irrigation fluid 19 based on the temperature and color of the grass. In one embodiment, once the appropriate quantity of irrigation fluid 19 has been calculated for a subregion 34, only a certain percentage (for example, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% or 90%) of the calculated quantity is applied over the subregion 34. The temperature and/or color of the grass is then checked and if an acceptable temperature and/or color are measured, irrigating is concluded (up to 100%) for that subregion 34. However, if the measured temperature and/or color are not acceptable, then an additional percentage (for example, another 10%, 20%, 30%, 40% or 50%) of the calculated fluid is applied over the subregion 34. The irrigation unit 20 continues to take the measurements and apply irrigation fluid 19 in this manner until acceptable measurements are obtained or until the irrigation quantity exceeds the calculated amount by a certain predetermined percentage. If the latter occurs, the unit control system 240 reports to the main control system 22 that there may be a problem at that subregion 34 or irrigation unit 20 serving that subregion 34. In the above example, the algorithm includes a troubleshooting routine which tries to ensure that the proper amount of irrigation fluid 19 is being applied for the conditions and type of grass in the subregion 34. This is accomplished by repeatedly monitoring the temperature and color of the subregion 34 after applying irrigation fluid 19 to the subregion 34 and if the monitored temperature and/or color are not acceptable, more irrigation fluid 19 is applied. After some point however, when the temperature and/or color are still not within an acceptable range, the unit control system 240 communicates a problem to the main control system 22. The main control system 22 can then notify a system operator that there is a problem with the specifically numbered irrigation unit 20, and the irrigation unit 20 can be disabled until it can be manually troubleshooted or otherwise repaired. Alternatively, the problem can be flagged for that irrigation unit 20 and it will continue watering at the previous rates adjusted in accordance with the measured sensor readings until maintenance corrects the problem. Additionally, the unit control system 240 can use an algorithm that uses the same parameters, but which also takes into account previous readings of those parameters at past times/days/hours, in order to calculate the amount of irrigation fluid 19 that should be applied. By continuously using the information from previous irrigation sequences, the unit control system 240 is a “smart system” to provide more efficient and optimized irrigation to a given area. Algorithms have been described herein as being executed by the unit control systems 240 and others by the main control system 22. One skilled in the art would recognize that the main control system 22 could perform all control algorithms. Similarly, the unit control systems 240 can perform the control algorithms carried out by the main control system 22, other than the overall sequencing algorithm. While the particular embodiments of the automated irrigation system 10 and the irrigation units 20 as illustrated herein are fully capable of satisfying the needs and providing the advantages herein before stated, it is to be understood that it is merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as described in the appended claims. | <SOH> BACKGROUND <EOH>Water is becoming an increasingly valuable and scarce commodity both in the United States and abroad. In particular, extreme drought conditions are common in arid regions such as the desert southwestern United States, although a decreased level of precipitation and resulting low water supplies can occur just about anywhere at various times. To compound matters, substantial amounts of water are squandered due to inefficient and ineffective conventional irrigation systems, for a variety of reasons. For example, typical irrigation units distribute water in a full round, half-round, quarter-round or an adjustable-type circular pattern. Thus, no matter how the irrigation units are arranged, obtaining consistent water coverage over a rectangular watering area is difficult or impossible. Watering normally occurs to prevent brown spots, resulting in overwatering in basically all other areas. In fact, in order to ensure that all areas are adequately irrigated, overlapping spray regions occur, which can result in certain areas receiving 300% or more of the necessary amount of water. Further, runoff from elevated areas such as mounds, slopes or hills causes ponding in lower areas, which can ultimately result in the higher areas absorbing an insufficient amount of water, while the lower areas are being saturated with water. Thus, watering occurs indiscriminately whether certain areas of the ground are wet or dry. In addition, in hot, windy conditions, water has a higher evaporation rate and may not actually reach the ground in the intended location, if at all. Moreover, different types of grass, trees or other foliage require varying levels of irrigation. These problems are exacerbated when the watering area is irregularly-shaped and includes areas that do not require water, such as walkways, driveways, fountains, ponds or other surfaces or features. Consequently, a significant quantity of water is routinely wasted, resulting in higher water bills and lower reservoirs. Further, the cost for pumping large amounts of water can result in increasingly high electrical expenses. In large turf areas, such as on golf courses, excessive and inefficient watering can give rise to enormous costs to the owner, thereby making maintaining a lush, green golf course prohibitive. Further, turf and soil maintenance is significantly increased due to the deposits of minerals, chemicals and salts that are left in the soil from irrigation. This is particularly a problem where reclaimed water having a high total dissolved solids (TDS) content is used for irrigation. These minerals, chemicals and salts can reduce absorption of the water into the soil, can change the pH of the soil, and/or can make the soil excessively salty, inhibiting growth of vegetation in the soil. | <SOH> SUMMARY <EOH>The present invention is directed to an irrigation system that includes one or more irrigation units for irrigating an area with a fluid from a fluid source. In one embodiment, the irrigation unit includes a housing, a nozzle, an electronic component, and a power generator. The nozzle is directly or indirectly secured to the housing and the nozzle is in fluid communication with the fluid source so that fluid from the fluid source is transferred to the nozzle. The electronic component is directly, indirectly, mechanically and/or electrically secured and/or coupled to the housing. The power generator generates electrical energy that is transferred to the electronic component. With this design, separate electrical power lines do not have to be directed to each of the irrigation units of the irrigation system. In one embodiment, the power generator directly transfers at least a portion of the electrical energy to the electronic component of the irrigation unit. As provided herein, the power generator can be a turbine type generator having a turbine that is in fluid communication with the fluid source. With this design, flow of the fluid from the fluid source to the nozzle causes the turbine to rotate and the power generator to generate electrical energy. Alternatively, for example, the power generator can include a solar panel or a water electrolysis unit that generates electrical energy. The power generator can be positioned near and/or within the housing. Moreover, the power generator can be directly or indirectly secured to the housing. For example, the electronic component can be a power storage unit, a control system, and/or another type of component that utilizes, stores, or transfers electrical energy. The power storage unit can include one or more batteries and/or capacitors. The present invention is also directed to an irrigation system that includes an irrigation unit, a method for generating electrical energy for an irrigation unit, and a method for storing electrical energy for an irrigation unit. | 20040120 | 20060829 | 20050721 | 60911.0 | 0 | NGUYEN, DINH Q | IRRIGATION UNIT INCLUDING A POWER GENERATOR | SMALL | 0 | ACCEPTED | 2,004 |
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10,762,147 | ACCEPTED | Foldable frame structure for foldable table | A foldable frame includes two U-shaped tabletop supports mounted underneath two table panels respectively, two folding hinges spacedly mounted between the two tabletop supports to pivotally connect the two tabletop supports with each other such that the tabletop is adapted to fold between a folded position that the two table panels are overlappedly folded with each other and an unfolded position that the two table panels are aligned edge-to-edge, and two leg frames foldably connected with the tabletop supports respectively. As a result, the foldable frame is capable of not only supporting the tabletop but also folding the tabletop in half so as to reduce the size of the foldable table. | 1. A foldable table, comprising: a tabletop comprising two table panels; and a foldable frame, which comprises: two tabletop supports mounted underneath said two table panels respectively, wherein each of said table supports, having a U-shaped, has two longitudinal supports extended along two longitudinal edge portions of said respective table panel and a transverse support integrally extended between said two longitudinal supports to extend along an inner transverse edge portion of said respective table panel; two folding hinges spacedly mounted between said two tabletop supports to pivotally connect said two tabletop supports with each other such that said tabletop is adapted to fold from a folded position that said two table panels are overlappedly folded with each other to an unfolded position that said two table panels are aligned edge-to-edge; and two leg frames foldably connected with said tabletop supports respectively, wherein each of said leg frames comprises a standing leg having an upper portion pivotally connected to said respective tabletop support and a retaining frame pivotally coupling with said standing leg to retain said standing leg at a standing position that said standing leg is pivotally and perpendicularly folded to said respective table panel while said standing leg is adapted to pivotally fold to rest on a bottom side said respective table panel. 2. The foldable table, as recited in claim 1, wherein each of said tabletop supports further comprises a connecting member disposed within said longitudinal supports, wherein each of said retaining frames has a leg coupling end pivotally coupling with said respective standing leg and a table coupling end pivotally connected to said connecting member so as to retain said standing leg at said standing position. 3. The foldable table, as recited in claim 2, wherein each of said connecting members is transversely mounted between said respective longitudinal supports at a position between said standing leg and said transverse support. 4. The foldable table, as recited in claim 2, wherein each of said connecting members is longitudinally extended between said longitudinal supports, wherein said connecting member has one end rotatably connected to said respective standing leg and another opposed end securely connected to said transverse support. 5. The foldable table, as recited in claim 1, wherein each of said folding hinges comprises a pivot hinge and two hinge arms opposedly extended from said pivot hinge to securely connect to two inner ends of said two corresponding longitudinal supports of said tabletop supports respectively so as to pivotally connect said two tabletop supports. 6. The foldable table, as recited in claim 3, wherein each of said folding hinges comprises a pivot hinge and two hinge arms opposedly extended from said pivot hinge to securely connect to two inner ends of said two corresponding longitudinal supports of said tabletop supports respectively so as to pivotally connect said two tabletop supports. 7. The foldable table, as recited in claim 4, wherein each of said folding hinges comprises a pivot hinge and two hinge arms opposedly extended from said pivot hinge to securely connect to two inner ends of said two corresponding longitudinal supports of said tabletop supports respectively so as to pivotally connect said two tabletop supports. 8. The foldable table, as recited in claim 5, wherein each of said table panels comprises two longitudinal rims longitudinally extended from said longitudinal edge portions of said respective table panel, wherein each of said longitudinal rims has two supporting walls downwardly extended from said bottom side of said respective table panel to define a support channel between said two supporting walls to receive said respective longitudinal support of said tabletop support so as to retain said longitudinal support under said table panel in position. 9. The foldable table, as recited in claim 6, wherein each of said table panels comprises two longitudinal rims longitudinally extended from said longitudinal edge portions of said respective table panel, wherein each of said longitudinal rims has two supporting walls downwardly extended from said bottom side of said respective table panel to define a support channel between said two supporting walls to receive said respective longitudinal support of said tabletop support so as to retain said longitudinal support under said table panel in position. 10. The foldable table, as recited in claim 7, wherein each of said table panels comprises two longitudinal rims longitudinally extended from said longitudinal edge portions of said respective table panel, wherein each of said longitudinal rims has two supporting walls downwardly extended from said bottom side of said respective table panel to define a support channel between said two supporting walls to receive said respective longitudinal support of said tabletop support so as to retain said longitudinal support under said table panel in position. 11. The foldable table, as recited in claim 8, wherein each of said table panels has a receiving cavity formed within said two longitudinal rims and said bottom side of said table panel, wherein each of said receiving cavity has a predetermined depth to receive said respective standing leg therein so as to overlappedly fold said table panels with each other. 12. The foldable table, as recited in claim 9, wherein each of said table panels has a receiving cavity formed within said two longitudinal rims and said bottom side of said table panel, wherein each of said receiving cavity has a predetermined depth to receive said respective standing leg therein so as to overlappedly fold said table panels with each other. 13. The foldable table, as recited in claim 10, wherein each of said table panels has a receiving cavity formed within said two longitudinal rims and said bottom side of said table panel, wherein each of said receiving cavity has a predetermined depth to receive said respective standing leg therein so as to overlappedly fold said table panels with each other. 14. The foldable table, as recited in claim 8, wherein a height of said respective standing leg is shorter than a length of said longitudinal support such that said standing leg is adapted to pivotally folded within said respective tabletop support to rest on said respective table panel so as to overlappedly fold said table panels with each other. 15. The foldable table, as recited in claim 9, wherein a height of said respective standing leg is shorter than a length of said longitudinal support such that said standing leg is adapted to pivotally folded within said respective tabletop support to rest on said respective table panel so as to overlappedly fold said table panels with each other. 16. The foldable table, as recited in claim 10, wherein a height of said respective standing leg is shorter than a length of said longitudinal support such that said standing leg is adapted to pivotally folded within said respective tabletop support to rest on said respective table panel so as to overlappedly fold said table panels with each other. 17. The foldable table, as recited in claim 3, wherein each of said table panels has an inner transverse biasing wall arranged in such a manner that when said table panels are folded at said unfolded position, said two biasing walls of said table panels are biased with each other to align said two table panels side-by-side so as to block up a further pivot movement of said tabletop. 18. The foldable table, as recited in claim 4, wherein each of said table panels has an inner transverse biasing wall arranged in such a manner that when said table panels are folded at said unfolded position, said two biasing walls of said table panels are biased with each other to align said two table panels side-by-side so as to block up a further pivot movement of said tabletop. 19. The foldable table, as recited in claim 8, wherein each of said table panels has an inner transverse biasing wall arranged in such a manner that when said table panels are folded at said unfolded position, said two biasing walls of said table panels are biased with each other to align said two table panels side-by-side so as to block up a further pivot movement of said tabletop. 20. The foldable table, as recited in claim 11, wherein each of said table panels has an inner transverse biasing wall arranged in such a manner that when said table panels are folded at said unfolded position, said two biasing walls of said table panels are biased with each other to align said two table panels side-by-side so as to block up a further pivot movement of said tabletop. | BACKGROUND OF THE PRESENT INVENTION 1. Field of Invention The present invention relates to a foldable table, and more particularly to a foldable frame structure for a foldable table, which comprises two tabletop supports which are not only capable of supporting the tabletop, but also folding the tabletop in half so as to reduce the size of the foldable table for convenient storage and transportation. 2. Description of Related Arts A conventional foldable table generally comprises a tabletop and a supporting frame which comprises a tabletop reinforcing frame and a foldable leg frame connected thereunder in a pivotally foldable manner. When the foldable is in use, the leg frame is pivotally unfolded and extended to support the tabletop at an elevated height, and when the foldable table is not in use, the leg frame is capable of being folded towards the tabletop for reduction in its overall size so as to facilitate easy storage and transportation. Traditionally, most of the improvements for conventional foldable tables have been overwhelmingly concentrated on the leg frame. Engineers and researchers alike have devoted themselves in developing new kinds of leg frames and the foldable mechanism in order to make the foldable table easier to fold, more compact in size and more secure in structure. Unfortunately however, it is the bulky tabletop which causes the main well-known disadvantages for conventional foldable tables. What's worse is that it seems that little efforts have been done in improving the tabletop and the supporting frame thereunder. Although it is true to say that by improving foldable mechanism of the leg frames, then it is possible to make conventional foldable tables to be more compact and optimal, by not developing the tabletop, which is the major cause of making the whole foldable table bulky and inconvenient, the core problems regarding conventional the foldable tables cannot be resolved. Although it is conceived that by altering the structure of the tabletop may severely deteriorate the overall stability and security of the foldable table, it should not prohibit further development in an attempt to seek an optimal solution to the conventional foldable tables. SUMMARY OF THE PRESENT INVENTION A main object of the present invention is to provide a foldable frame structure for a foldable table, which comprises two tabletop supports which are not only capable of supporting the tabletop, but also folding the tabletop in half so as to reduce the size of the foldable table for convenient storage and transportation. Another object of the present invention is to provide a foldable frame structure for a foldable table, which is capable of supporting a tabletop in a foldably movable manner without affecting the stability of the foldable table. Another object of the present invention is to provide a foldable frame structure for a foldable table, which does not involve complicated and expensive mechanical components and processes so as to minimize the manufacturing cost and the ultimate selling price of the present invention. Another object of the present invention is to provide a foldable frame structure for a foldable table, which does not significantly alter the structural design of the conventional foldable table so that the present invention is easy to operate and ready to substitute the conventional foldable tables. Accordingly, in order to accomplish the above objects, the present invention provides a foldable table, comprising: a tabletop which comprises two table panels; and a foldable frame, which comprises: two tabletop supports mounted underneath the two table panels respectively, wherein each of the table supports, having a U-shaped, has two longitudinal supports extended along two longitudinal edge portions of the respective table panel and a transverse support integrally extended between the two longitudinal supports to extend along an inner transverse edge portion of the respective table panel; two folding hinges spacedly mounted between the two tabletop supports to pivotally connect the two tabletop supports with each other such that the tabletop is adapted to fold from a folded position that the two table panels are overlappedly folded with each other to an unfolded position that the two table panels are aligned edge-to-edge; and two leg frames foldably connected with the tabletop supports respectively, wherein each of the leg frames comprises a standing leg having an upper portion pivotally connected to the respective tabletop support and a retaining frame pivotally coupling with the standing leg to retain the standing leg at a position that the standing leg is pivotally and perpendicularly folded to the respective table panel while the standing leg is adapted to pivotally fold to rest on the respective table panel. These and other objectives, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is perspective view of a foldable table according to a preferred embodiment of the present invention. FIG. 2 is an exploded perspective view of the foldable table according to the above preferred embodiment of the present invention. FIG. 3 is a schematic diagram of the foldable table according to the above preferred embodiment of the present invention, illustrating that the foldable table being folded in a folded position. FIG. 4 is a schematic diagram of the foldable table according to the above preferred embodiment of the present invention, illustrating that the folding movement of the foldable table. FIG. 5 is an alternative mode of the foldable table according to the above preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 and FIG. 2 of the drawings, a foldable table 1 according to a preferred embodiment of the present invention is illustrated, wherein the foldable table 1 comprises a tabletop 10 and a foldable frame 20 foldably mounted underneath the tabletop 10. The tabletop 10 comprises two table panels 11 each having a rectangular shape and an upper utility surface formed on the respective table panel 11 for a supporting a wide variety of objects. The table panels 11 are preferably embodied as being made of strong yet light materials, such as plastic materials or composites, so as to on the one hand, securely support the things on top of the utility surface, and on the other hand, minimize the burden imposed on the foldable frame 20 and facilitate easy transportation. As shown in FIG. 2, each of the table panels 11 has an inner transverse biasing wall 112 arranged in such a manner that when the table panels 11 are folded at the unfolded position, the two biasing walls 112 of the table panels 11 are biased with each other to align the two table panels 11 side-by-side so as to block up a further pivot movement of the tabletop 10. The foldable frame 20 comprises two tabletop supports 21 mounted underneath the two table panels 11 respectively for substantially supporting and reinforcing the two table panels 11. Each of the tabletop supports 21 has two longitudinal supports 211 extended along two longitudinal side portions of the respective table panel 11 in parallel, and a transverse support 212 integrally extended between the two longitudinal supports 211 to extend along an inner transverse edge portion of the respective table panel 11 to define a U-shaped table support 21 formed by the longitudinal supports 211 and the transverse support 212. In other words, the two tabletop supports 21 are opposedly mounted underneath the two table panels 11 respectively wherein each of the U-shaped tabletop supports 21 is adapted to substantially and evenly support a loading on the respective table panel 11. The foldable frame 20 further comprises two folding hinges 23 spacedly mounted between the two tabletop supports 21 to pivotally connect the two tabletop supports 21 with each other in such a manner that the tabletop 10 is adapted to fold from a folded position to an unfolded position, wherein in the folded position, as shown in FIG. 3 of the drawings, the two table panels 11 are overlappedly and pivotally folded with each other so as to reduce the overall foldable table 1 into a compact size for easy storage and transportation, as shown in FIG. 3, wherein in the unfolded position, the table panels 11 are pivotally extended to align in a side-by-side manner so that the upper utility surfaces of the two table panels 11 are substantially aligned. It is worth to mention that when the tabletop 10 is in the unfolded position, the two table panels 11 are pivotally unfolded and aligned side-by-side so that each of the table panels 11 is arranged to bias against each other in their respective inner transverse edge portions, such that they are interlocked to retain in position. According to the preferred embodiment, each of the folding hinges 23 is mounted between two inner ends of the corresponding longitudinal supports 211 so as to connect the two tabletop supports 21 in a pivotally foldable manner. Each of the folding hinges 23 comprises a pivot hinge 231 and two hinge arms 232 opposedly extended from the pivot hinge 231 to securely connect to two inner ends of the two corresponding longitudinal supports 211 of the tabletop supports 21 respectively so as to pivotally connect the two tabletop supports 21. The foldable frame 20 further comprises two leg frames 22 mounted underneath the two tabletop supports 21 respectively in a pivotally foldable manner, wherein each of the leg frames 22 comprises a standing leg 221 having an upper transverse portion 2211 pivotally connected to the respective tabletop support 21, and a retaining frame 222 pivotally coupling the respective standing leg 221 with the respective tabletop support 21 so as to retain the standing leg 221 at a standing position where the standing leg 221 is arranged to be pivotally and perpendicularly extended to stand on a ground surface, and at a resting position where the standing leg 221 is pivotally fold to rest on a bottom side of the respective table panel 11. Moreover, each of the standing leg 221 has two leg members 2212 downwardly and integrally extended from the upper transverse portion 2211 of the standing leg 221 so as to form a support on the foldable table 1 on the ground surface. In other words, the two leg frames 22 form four supports for the foldable table 1 so as to securely support the tabletop 10 at an elevated above the ground surface. Referring to FIGS. 2 and 4, each of the tabletop supports 21 further comprises a connecting member 213 disposed within the longitudinal supports 211 to support the respective standing leg 221 in position. Each of the connecting members 213 is transversely mounted between the two longitudinal supports 211 of the respective tabletop support 21 at a position between the standing leg 221 and the transverse support 212, wherein each of the retaining frame 222 has a leg coupling end pivotally connected to the connecting member 213 and a table coupling end pivotally connected to the connecting member 213 so as to retain the standing leg 221 at the standing position. Alternatively, each of said connecting members 213′ is longitudinally extended between the longitudinal support 211, wherein the connecting member 213′ has one end rotatably connected to the respective standing leg 221 and another opposed end securely connected to the transverse support 212, as shown in FIG. 5. In other words, the connecting member 213′ is longitudinally extended from the respective transverse support 212 to the respective upper transverse portion 2211 of the respective standing leg 221 via a pivot joint 24′. As a result, the table coupling end of each of the retaining frames 222 is pivotally connected to the respective connecting member 213′ and the leg coupling end of each of the retaining frames 222 is pivotally connected to the respective standing leg 221 while the standing leg 221 is capable of pivotally moving about the two longitudinal supports 211 so as to move between the resting position and the standing position, as shown in FIG. 5. As shown in FIG. 2, each of the retaining frames 222 comprises a linking member 2221 defining the table coupling end pivotally connected to the connecting member 213 of the respective tabletop support 21, and a pair of pivotal arms 2222 which is pivotally connected to the linking member 2221 with the respective standing leg 221 and defines the leg coupling end to pivotally connect with the standing leg 221, in such a manner that the leg frame 22 is capable of pivotally folding between the standing position and the resting position. Moreover, each of the retaining frame 222 further comprises means for retaining the retaining frame in the standing position, wherein the retaining means comprises a tubular lock 2223 slidably attached on the linking member 2221 in such a manner that when the leg frame 22 is in the standing position, the tubular lock 2223 is arranged to downwardly slide along the linking member 2221 so as to receive the upper end portions of the pivotal arms 2222 for restricting further pivotal movements thereof. It is worth to mention that when the foldable table 1 is unfolded to stand on a ground surface, downward gravitational force will pull the tubular locks 2223 sliding downwardly along the linking members 2221 respectively so as to automatically retain the leg frames 22 in the standing position. As shown in FIG. 2, each of the table panels 11 comprises two longitudinal rims 12 longitudinally extended from the longitudinal edge portions of the respective table panel 11, wherein each of the longitudinal rims 12 has two supporting walls 121 downwardly extended from the bottom side of the respective table panel 11 to define a support channel 122 between the two supporting walls 121 to receive the respective longitudinal support 211 of the tabletop support 21 so as to retain the longitudinal support 211 under the table panel 11 in position. Each of the table panels 11 has a receiving cavity 111 formed within the two longitudinal rims 13 and the bottom side of said table panel 11, wherein each of the receiving cavity 111 has a predetermined depth to receive the respective standing leg 221 therein so as to overlappedly fold the table panels 11 with each other. Moreover, a height of each of the standing legs 221 of each of the leg frames 22 should be shorter than a length of the respective longitudinal support 211 such that the leg frame 22 is adapted to pivotally folding towards and being received within the respective tabletop support 21 to rest on the bottom side of the table panel 11. Therefore, the two tabletop supports 21 are capable of pivotally and overlappedly folding towards each other into the folded position. According to the preferred embodiment, the operation of the present invention is as follows: when the foldable table 1 is to be utilized, a user is able to unfold the tabletop 10 by pivotally folding the two table panels 11 at an alignment that the two table panels 11 are extended side by side. Then, the user is able to pivotally fold the leg frames 22 from the receiving cavities 111 to perpendicularly extend from the table panels 11 respectively. Since the leg frames 22 and the table panels 11 are locked and retained in position, the foldable table 1 is capable of providing a secure support to the objects disposed on the utility surface. Conversely, when the foldable table 1 is folded to be stored, the user can sequentially fold the leg frames 22 and then the tabletop 10 to reduce the foldable table into a compact structure, as shown in FIGS. 3 and 4. It is important to point out that each table panel 11 is evenly and securely reinforced and supported by the respective tabletop supports 21 yet the tabletop 10 is foldable to become a compact structure, thus substantially resolving the inherent tension that foldable structures are generally not secure enough. One skilled in the art will understand that the embodiment of the present invention as shown in the drawings and described above is exemplary only and not intended to be limiting. It will thus be seen that the objects of the present invention have been fully and effectively accomplished. It embodiments have been shown and described for the purposes of illustrating the functional and structural principles of the present invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims. | <SOH> BACKGROUND OF THE PRESENT INVENTION <EOH>1. Field of Invention The present invention relates to a foldable table, and more particularly to a foldable frame structure for a foldable table, which comprises two tabletop supports which are not only capable of supporting the tabletop, but also folding the tabletop in half so as to reduce the size of the foldable table for convenient storage and transportation. 2. Description of Related Arts A conventional foldable table generally comprises a tabletop and a supporting frame which comprises a tabletop reinforcing frame and a foldable leg frame connected thereunder in a pivotally foldable manner. When the foldable is in use, the leg frame is pivotally unfolded and extended to support the tabletop at an elevated height, and when the foldable table is not in use, the leg frame is capable of being folded towards the tabletop for reduction in its overall size so as to facilitate easy storage and transportation. Traditionally, most of the improvements for conventional foldable tables have been overwhelmingly concentrated on the leg frame. Engineers and researchers alike have devoted themselves in developing new kinds of leg frames and the foldable mechanism in order to make the foldable table easier to fold, more compact in size and more secure in structure. Unfortunately however, it is the bulky tabletop which causes the main well-known disadvantages for conventional foldable tables. What's worse is that it seems that little efforts have been done in improving the tabletop and the supporting frame thereunder. Although it is true to say that by improving foldable mechanism of the leg frames, then it is possible to make conventional foldable tables to be more compact and optimal, by not developing the tabletop, which is the major cause of making the whole foldable table bulky and inconvenient, the core problems regarding conventional the foldable tables cannot be resolved. Although it is conceived that by altering the structure of the tabletop may severely deteriorate the overall stability and security of the foldable table, it should not prohibit further development in an attempt to seek an optimal solution to the conventional foldable tables. | <SOH> SUMMARY OF THE PRESENT INVENTION <EOH>A main object of the present invention is to provide a foldable frame structure for a foldable table, which comprises two tabletop supports which are not only capable of supporting the tabletop, but also folding the tabletop in half so as to reduce the size of the foldable table for convenient storage and transportation. Another object of the present invention is to provide a foldable frame structure for a foldable table, which is capable of supporting a tabletop in a foldably movable manner without affecting the stability of the foldable table. Another object of the present invention is to provide a foldable frame structure for a foldable table, which does not involve complicated and expensive mechanical components and processes so as to minimize the manufacturing cost and the ultimate selling price of the present invention. Another object of the present invention is to provide a foldable frame structure for a foldable table, which does not significantly alter the structural design of the conventional foldable table so that the present invention is easy to operate and ready to substitute the conventional foldable tables. Accordingly, in order to accomplish the above objects, the present invention provides a foldable table, comprising: a tabletop which comprises two table panels; and a foldable frame, which comprises: two tabletop supports mounted underneath the two table panels respectively, wherein each of the table supports, having a U-shaped, has two longitudinal supports extended along two longitudinal edge portions of the respective table panel and a transverse support integrally extended between the two longitudinal supports to extend along an inner transverse edge portion of the respective table panel; two folding hinges spacedly mounted between the two tabletop supports to pivotally connect the two tabletop supports with each other such that the tabletop is adapted to fold from a folded position that the two table panels are overlappedly folded with each other to an unfolded position that the two table panels are aligned edge-to-edge; and two leg frames foldably connected with the tabletop supports respectively, wherein each of the leg frames comprises a standing leg having an upper portion pivotally connected to the respective tabletop support and a retaining frame pivotally coupling with the standing leg to retain the standing leg at a position that the standing leg is pivotally and perpendicularly folded to the respective table panel while the standing leg is adapted to pivotally fold to rest on the respective table panel. These and other objectives, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims. | 20040122 | 20061128 | 20050728 | 65544.0 | 1 | AYRES, TIMOTHY MICHAEL | FOLDABLE FRAME STRUCTURE FOR FOLDABLE TABLE | SMALL | 0 | ACCEPTED | 2,004 |
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10,762,167 | ACCEPTED | Axial piston machines | This invention relates to internal combustion engines with cylinders arranged parallel to the main shaft and where reciprocating movements of the pistons are converted to rotation by means of a Z-crank mechanism and motion converter, or conversely to systems such as pumps and compressors wherein rotation of the Z-crank and motion converter produces reciprocating motions of the pistons. The motion converter is prevented from rotation by a reaction control shaft or by a gear train. Connecting rods are prevented from rotating about their long axes. Double-ended configurations can be either opposed cylinder or opposed piston, and may include multiple pairs of pistons with each pair in a common cylinder. The Z-crank may be moved axially for the purpose of varying the compression ratio. Variation of the compression ratio is controlled by an engine control unit and is adjusted to optimize engine performance under varying loads and other conditions. | 1. An engine or other device having a Z-crank operated by axially arranged pistons and cylinders whose axes parallel the rotational axis of the Z-crank and where the motion converter is prevented from rotating as it nutates by means of: a) a reaction control shaft b) the axis of rotation of which is parallel to the axis of rotation of the Z-crank c) the reaction control shaft, having a cylindrical section parallel to and offset from its axis of rotation d) so as to provide an eccentric bearing surface e) for a bushing mounted to the motion converter f) that rotates relative to the motion converter and slides and rotates relative to the reaction control shaft g) where the reaction control shaft is driven by gears or other means to rotate at twice the Z-crank speed. 2. An engine or other device as described in claim 1 where there are two complete sets of motion converters, connecting rods and pistons combined face-to-face and there is a double Z-crank. 3. An engine or other device as described in claim 1 where there are two complete sets of motion converters, connecting rods and pistons combined back-to-back and there is a double Z-crank. 4. An engine or other device having a Z-crank operated by axially arranged pistons and cylinders whose axes parallel the rotational axis of the Z-crank and where the motion converter is prevented from rotating as it nutates by means of: a) a stationary gear coaxial to the axis of rotation of the Z-crank and fixed to the engine housing b) engaged with a planetary gear carried on the Z-crank c) the planetary gear and a third gear fixed together d) the third gear engaged with a fourth gear that is fixed to the motion converter e) the ratio between the planetary gear and the stationary gear is the same as the ratio between the third gear and the fourth gear. 5. An engine or other device as described in claim 4 where there are two complete sets of motion converters, connecting rods and pistons combined face-to-face and there is a double Z-crank. 6. An engine or other device as described in claim 4 where there are two complete sets of motion converters, connecting rods and pistons combined back-to-back and there is a double Z-crank. 7. An engine or other device having a Z-crank operated by axially arranged pistons and cylinders whose axes parallel the rotational axis of the Z-crank and where the Z-crank is provided with splines or other means at both ends to allow for axial movement of the Z-crank relative to its output connection and flywheel and its valve gear and accessory drive. 8. An engine or other device as described in claim 7 where there are two complete sets of motion converters, connecting rods and pistons combined face-to-face and there is a double Z-crank. 9. An engine or other device as described in claim 7 where there are two complete sets of motion converters, connecting rods and pistons combined back-to-back and there is a double Z-crank. 10. An engine or other device having a Z-crank operated by axially arranged pistons and cylinders whose axes parallel the rotational axis of the Z-crank and where the compression ratio of the device is automatically varied during operation by means of: a) a mechanical actuator b) electronically controlled by an engine control unit c) that displaces the Z-crank and motion converter along its axis d) in response to variations in power demand, load and other conditions e) as input to the engine control unit from sensors. 11. An engine or other device as described in claim 10 where there are two complete sets of motion converters, connecting rods and pistons combined face-to-face and there is a double Z-crank. 12. An engine or other device as described in claim 10 where there are two complete sets of motion converters, connecting rods and pistons combined back-to-back and there is a double Z-crank. 13. An engine or other device having a Z-crank operated by axially arranged pistons and cylinders whose axes parallel the rotational axis of the Z-crank and where the connecting rods are provided at one or both ends with split shell bearings having: a) a spherical surface on the inner surface of the bearing b) a cylindrical surface on the outer surface of the bearing c) a means for locating and fixing the bearing to the connecting rod d) auxiliary cylindrical bearing surfaces to engage trunnion pins and concentrically supporting a trunnion having: a) a spherical outer surface b) a cylindrical inner surface for interface to a wrist pin c) cylindrical trunnion pins to prevent rotation of the connecting rod about its long axis. 14. An engine or other device having a Z-crank operated by axially arranged pistons and cylinders whose axes parallel the rotational axis of the Z-crank where: a) the piston and associated connecting rod are fixed together b) the outside of the piston is tapered at one or both ends c) the largest diameter section of the piston is spherical in shape and is slightly smaller in diameter than the cylinder into which it is fitted. 15. An engine or other device having a Z-crank operated by axially arranged pistons and cylinders whose axes parallel the rotational axis of the Z-crank where: a) the piston and associated connecting rod are combined into a single piece b) the outside of the piston is tapered at one or both ends c) the largest diameter section of the piston is spherical in shape and is slightly smaller in diameter than the cylinder into which it is fitted. | CROSS REFERENCE TO RELATED APPLICATIONS NOT APPLICABLE STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT NOT APPLICABLE REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISK APPENDIX NOT APPLICABLE BACKGROUND OF THE INVENTION The following disclosure relates generally to machines and apparatuses having axial piston arrangements and, more particularly, to apparatuses and methods for converting reciprocating linear motion of one or more pistons into rotary motion of an associated shaft oriented in parallel to the piston motion. Various apparatuses are known that convert movement of a working fluid within a changeable cylinder volume into rotary motion of an input/output shaft. Conventional internal combustion engines, compressors, and pumps are just a few of such apparatuses. In conventional arrangements, the pistons are connected via connecting rods to a crankshaft that rotates on an axis oriented perpendicular to the direction of travel of the piston. The theoretical advantages of the axial piston arrangement have been well understood for many years, but no prior effort has succeeded in the marketplace. The primary difficulty in implementing an axial piston engine is in the means provided for preventing rotation of the motion converter, or as commonly referred to, the “wobble plate.” BRIEF SUMMARY OF THE INVENTION It is an object of the invention to reduce friction losses in internal combustion engines and the like. Another object of the invention to provide for variable compression ratio in internal combustion engines. A further object of the invention is to provide a piston motion that is harmonic in nature and can be readily balanced and thereby reduce vibration. It is an additional object of the invention to provide an improved means for preventing the rotation of the motion converter in an axial piston machine. Another object of the invention is to provide a means for preventing the rotation of the connecting rods in an axial piston machine. Yet another object of the invention is to provide for a one-piece or rigidly attached piston and connecting rod in an axial piston machine. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of an axial piston apparatus configured in accordance with an embodiment of the invention. FIG. 2 is an isometric view of the axial piston apparatus of FIG. 1 with various portions removed for purposes of clarity. FIG. 3 illustrates a side elevation view and a top plan view of the axial piston apparatus of FIG. 2. FIG. 4 is an exploded isometric view of the motion converter/Z-crank/reaction control shaft assembly of FIGS. 1-3 configured in accordance with embodiments of the invention. FIG. 5 is an isometric view of the Z-crank of FIG. 4 configured in accordance with an embodiment of the invention. FIG. 6 is an exploded isometric view of the motion converter and the Z-crank of FIGS. 4 and 5 configured in accordance with embodiments of the invention. FIG. 7 is a partially exploded isometric view of the reaction control shaft of FIGS. 1-4 configured in accordance with an embodiment of the invention. FIG. 8 is a partially cutaway isometric view of an axial piston apparatus having an anti-rotation gear train configured in accordance with another embodiment of the invention. FIG. 9 is a side elevational view of the axial piston apparatus of FIG. 8 with portions removed for purposes of clarity in accordance with an embodiment of the invention. FIG. 10 is an isometric view of the axial piston apparatus of FIG. 9 configured in accordance with an embodiment of the invention. FIG. 11 is a top view of the axial piston apparatus of FIG. 9 configured in accordance with an embodiment of the invention. FIG. 12 is an exploded isometric view of a piston/connecting rod assembly configured in accordance with an embodiment of the invention. FIG. 13 is an isometric view of an axial piston apparatus configured in accordance with yet another embodiment of the invention. FIG. 14 is an exploded isometric view of a one-piece piston/connecting rod assembly configured in accordance with another embodiment of the invention. FIG. 15 is an isometric view of an axial piston apparatus having opposed cylinders facing outwardly from each other in a back-to-back arrangement in accordance with an embodiment of the invention. FIG. 16 illustrates a side elevation view and a top view of the axial piston apparatus of FIG. 15 in accordance with an embodiment of the invention. FIG. 17 is an isometric view of an axial piston apparatus having opposed pistons facing toward each other in pairs sharing a common cylinder in accordance with an embodiment of the invention. FIG. 18 illustrates a side elevation view and a top view of the axial piston apparatus of FIG. 17. DETAILED DESCRIPTION The following disclosure is directed to apparatuses and methods for converting reciprocal linear motion of one or more pistons into rotary motion of an output power shaft whose rotational axis is parallel to ther motions of the pistons or, conversely, for converting rotary motion of a similarly configured input shaft into reciprocal linear motion of one or more pistons. Various embodiments of the invention can be applied to internal combustion engines, external combustion engines, air compressors, air motors, liquid fluid pumps, and the like where movement of a working fluid within a volume-changing cylinder results from/in rotary motion of an input/output shaft. In contrast to conventional engines, compressors, and pumps where the crankshaft's rotational axis is perpendicular to the motions of the pistons, an axial piston apparatus configured in accordance with embodiments of the present invention can have one or more cylinders aligned in parallel with the rotational axis of the input/output shaft. As described in greater detail below, such a configuration can further include the capability to dynamically vary the compression ratio in the cylinders to alter the performance characteristics of the apparatus. Certain embodiments of the apparatuses and methods described herein are described in the context of fluid pumps, fluid compressors, and internal combustion engines of both two- and four-stroke cycle designs. Accordingly, in these embodiments, the invention can include one or more features often associated with internal combustion engines, fluid pumps, or compressors such as fuel delivery systems, ignition systems, and/or various other engine/pump control functions. Because the basic structures and functions often associated with internal combustion engines, fluid pumps, fluid compressors and the like are known to those of ordinary skill in the relevant art, they have not been shown or described in detail here to avoid unnecessarily obscuring the described embodiments of the invention. Certain specific details are set forth in the following description and in FIGS. 1-18 provide a thorough understanding of various embodiments of the invention. Those of ordinary skill in the relevant art will understand, however, that the invention may have additional embodiments that may be practiced without several of the details described below. In addition, some well-known structures and systems often associated with engines, pumps, and compressors have not been shown or described in detail here to avoid unnecessarily obscuring the description of the various embodiments of the invention. In the drawings, identical reference numbers identify identical or at least generally similar elements. To facilitate the discussion of any particular element, the most significant digit or digits in any reference number refers to the figure in which that element is first introduced. For example, element 130 is first introduced and discussed in reference to FIG. 1. In addition, any dimensions, angles and other specifications shown in the figures are merely illustrative of particular embodiments of the invention. Accordingly, other embodiments of the invention can have other dimensions, angles and specifications without departing from the spirit or scope of the present disclosure. FIG. 1 is an isometric view of an axial piston apparatus 100 configured in accordance with an embodiment of the invention. For ease of reference, the phrase “axial piston apparatus” will be understood to include engines, pumps, compressors, etc. having the piston arrangement more or less as depicted, unless specifically identified otherwise. In one aspect of this embodiment, the apparatus 100 includes one or more cylinders 110 aligned in parallel with a rotational axis 131 of a Z-crank 130. Although the illustrated embodiment depicts three cylinders 110, in other embodiments, the engine 100 can include more or fewer cylinders 110 without departing from the spirit or scope of the present disclosure. As discussed in greater detail below, in those embodiments in which a four-stroke combustion process is utilized, it may be advantageous for the apparatus 100 to include an odd number of cylinders 110. In contrast, those embodiments of the apparatus 100 utilizing a two-stroke combustion process may include an odd or even number of cylinders 110. In another aspect of this embodiment, pistons 112 reciprocate back and forth within the cylinders 110 parallel to the Z-crank rotational axis 131. The pistons 112 are connected via connecting rods 114 to a “wobble-plate” or motion converter 120. As described in greater detail below, the motion converter 120 is rotatably attached to the Z-crank 130 about a nutation axis 133 such that the Z-crank 130 is free to rotate with respect to the motion converter 120 about the nutation axis 133. Accordingly, reciprocating motion of the pistons 112 in the cylinders 110 causes the motion converter 120 to nutate or wobble (but not rotate) relative to the Z-crank rotational axis 131. In a further aspect of this embodiment, the apparatus 100 also includes a reaction control shaft 150 slidably engaging the motion converter 130. As explained in greater detail below, the reaction control shaft 150 restricts rotational movement of the motion converter 130 while allowing the motion converter 130 to nutate relative to the Z-crank rotational axis 131. The reaction control shaft 150 is configured to accommodate this nutation by rotating about an axis 151 as the Z-crank 130 rotates about its rotational axis 131. A gear train 160 controls motion of the reaction control shaft 150 relative to the Z-crank 130. In operation, reciprocating motion of the pistons 112 within the cylinders 110 causes the motion converter 120 to nutate relative to the Z-crank rotational axis 131. Although the motion converter 120 nutates, it does not rotate a significant amount. Nutation of the motion converter 120 causes the Z-crank 130 to rotate relative to the motion converter 120 about the nutation axis 133. Such motion also causes the Z-crank 130 to rotate about the Z-crank axis 131. While the Z-crank 130 rotates, the reaction control shaft 150 also rotates about its axis 151 (e.g., at twice the Z-crank rotational speed) to accommodate the nutational movement of the motion converter 120 while restricting rotational movement of the motion converter 120. Accordingly, in an internal combustion engine embodiment, combustion of fuel gases in the cylinders 110 can impart linear motion to the pistons 112 which in turn causes the motion converter 120 to wobble or nutate relative to the Z-crank rotational axis 131 providing rotational shaft-power at the Z-crank 130. This shaft-power can be utilized for any one of many applications including propelling air, land, and sea vehicles. Alternatively, when used as a pump or air compressor, shaft-power can be applied to the Z-crank 130 causing it to rotate about the Z-crank rotational axis 131 and thereby nutate the motion converter 120. Nutation of the motion converter 120 in turn causes axial motion of the pistons 112 in the cylinders 110. Such motion can be used to pump water, air or another fluid to or from a reservoir or source (not shown) for many applications. In yet another aspect of this invention, the axial arrangement of the cylinders 110 relative to the Z-crank rotational axis 131 can advantageously facilitate compression ratio changes within the cylinders 110. For example, in one embodiment the apparatus 100 can include a support plate 140 that provides rotational support to the Z-crank 130 and the reaction control shaft 150. In the illustrated embodiment, the support plate 140 can be axially movable relative to the cylinders 110 back and forth parallel to the Z-crank rotational axis 131. Accordingly, as the support plate 140 moves toward the cylinders 110, the clearance between the top of the pistons 112 and the top of the combustion chamber within the cylinders 110 is reduced. As a result, such movement of the support plate 140 causes the compression ratio within the cylinders 110 to increase. Similarly, movement of the support plate 140 away from the cylinders 110 causes the compression ratio within the cylinders 110 to decrease. As will be appreciated by those of ordinary skill in the relevant art, controlling the compression ratio within the cylinders 110 in the foregoing manner can advantageously be used to alter or optimize various performance aspects of the axial piston apparatus 100. In one aspect of this embodiment, the axial piston apparatus 100 can include an actuator 142 operably connected to the support plate 140, and an engine control unit 144 (“ECU” 144) that provides control inputs to the actuator 142. In one embodiment, the actuator 142 can include a hydraulic actuator configured to move the support plate 140 back and forth relative to the cylinders 110. In other embodiments, other types of mechanical, hydraulic, pneumatic and other types of actuators can be used to move the support plate 140 in response to inputs from the ECU 144. The ECU 144 of the illustrated embodiment can include one or more facilities for receiving engine operating information and outputting control signals to the actuator 142. For example, in one embodiment, the ECU can include a processor and a controller. In other embodiments, the ECU can include other functionalities. In yet another embodiment, the ECU 144 may be at least substantially similar to ECUs for controlling conventional internal combustion engines. In this embodiment, however, the ECU 144, in addition to controlling engine functions such as fuel intake, ignition timing, and/or valve timing, can provide additional output signals to control the actuator 142 and move the support plate 140 in response to one or more of the engine operating parameters. In a further aspect of this embodiment, one or more engine sensors 146 can provide engine operating parameter input to the ECU 144. Such engine sensors can include, for example, airflow rate, combustion and/or exhaust temperatures, throttle position, vehicle speed, etc. In a further aspect of this embodiment, a variable compression axial piston engine in accordance with the present invention can be utilized to optimize engine performance to suit different operating conditions. For example, when the axial piston engine is operated at idle speeds, the compression in the combustion chambers can be reduced to enhance fuel efficiency. Alternatively, at higher RPMs, the compression within the combustion chambers can be increased. In other embodiments, the variable compression aspects of the present invention can be utilized in other ways to increase efficiency or performance. FIG. 2 is an isometric view of the axial piston apparatus 100 of FIG. 1 with the cylinders and housing removed for purposes of clarity. In one aspect of this embodiment, the connecting rods 114 are double-articulating connecting rods that can accommodate rotational movement about two axes at each end. For example, an upper wrist pin 218 joining the “small end” of the connecting rod 114 to the piston 112 is configured to gimbal or rotate in at least two axes with respect to the connecting rod 114. Similarly, a lower wrist pin 216 joining the “big-end” of the connecting rod 114 to the motion converter 120 is also able to gimbal or rotate about at least two axes with respect to the motion converter 120. Details of the connecting rod attachments will be described more fully below, as will an alternate embodiment of the invention wherein the connecting rods 114 are at least substantially fixed relative to the pistons 112. In this alternate embodiment, the pistons 112 are at least partially spherically shaped, as shown in crossisection 1312 to accommodate minor tilting motions of the connecting rods 114. The gear train 160 introduced above with reference to FIG. 1 is shown to good advantage in FIG. 2. In another aspect of this embodiment, the gear train 160 includes a Z-crank gear 262 rotatably coupled to a reaction control shaft gear 266 via an idler gear 264. Both the idler gear 264 and the reaction control shaft gear 266 can have one-half as many teeth as the Z-crank gear 262. Accordingly, this gear arrangement will cause the reaction control shaft 150 to rotate at twice the speed of the Z-crank 130. As explained in greater detail below, in one aspect of this embodiment, this speed is necessary so that an offset portion 351 of the reaction control shaft 150 that guides the motion converter 120 will complete two orbits about its rotational axis as the Z-crank 130 completes one full rotation and the motion converter 120 completes one full nutation. In other embodiments, other gear arrangements can be used to provide the requisite timing between the Z-crank 130 and the reaction control shaft 150 without departing from the spirit or scope of the present invention. FIG. 3 includes side elevation and top plan views of the axial piston apparatus 100 of FIG. 2. FIG. 3 illustrates how fore and aft motion of the support plate 140 changes the axial position of the pistons 112 relative to the cylinders 110 (not shown) thereby changing the compression ratio in the cylinders 110. In one aspect of this embodiment, the axial piston apparatus 100 includes a reaction control bearing 352 slidably and rotatably positioned on an offset bearing surface 351 of the reaction control shaft 150. As described in greater detail below, the reaction control bearing 352 allows the motion converter 120 to nutate about the Z-crank rotational axis 131 while restricting rotational motion of the motion converter 120. The reaction control bearing 352 further allows the motion converter 120 to travel back and forth along the offset bearing surface 351 as the motion converter 120 nutates. The reaction control bearing 352 can be configured to rotate relative to the offset bearing surface 351 to accommodate rotation of the reaction control shaft 150 about its rotational axis 151. FIG. 4 is an exploded isometric view of the motion converter/Z-crank/reaction control shaft assembly of FIGS. 1-3 configured in accordance with embodiments of the invention. In one aspect of this embodiment, the Z-crank assembly 130 includes a motion connection throw or bearing surface 432 configured to receive the motion converter 120. As explained above, the bearing surface 432 is aligned with the nutation axes 133. The Z-crank assembly 130 can further include fore and aft bearing surfaces 434 and 435 for rotationally supporting the Z-crank 130 relative to the housing of the axial piston apparatus 100 (FIG. 1). The fore and aft bearing surfaces 434 and 435 can be suitably supported in bearings to permit free rotation of the Z-crank 130 about the Z-crank rotational axis 131. As illustrated, the Z-crank rotational axis 131 intersects the nutational axis 133 at a location that is at least approximately centered on the motion converter bearing surface 432. Although the forward bearing surface 434 appears relatively short in FIG. 4, in other embodiments, the Z-crank 130 can extend further forward from the forward bearing surface 434 and provide rotational surfaces for actuating other mechanisms related to the axial piston apparatus 100. For example, as explained in greater detail below, in one embodiment the Z-crank 130 can be extended forward from the forward bearing surface 434 to provide camshaft lobes for actuating poppet-valves or other fluid control valves associated with combustion or pump processes. In another aspect of this embodiment, the motion converter 120 has a centerbore 422 including one or more bearings (e.g., needle bearings) configured to rotatably receive the Z-crank bearing surface 432. The motion converter 120 can further include a reaction control bearing bore 424 radially offset from the centerbore 422 and configured to rotatably receive the reaction control bearing 352. The reaction control bearing 352 can similarly include a control shaft bore 454 configured to slidably and rotatably receive the offset bearing surface 351 of the reaction control shaft 150. The reaction control shaft gear 266 is fixed to one end of the reaction control shaft 150 and is configured to be operably engaged with the Z-crank gear 262 fixed on the Z-crank 130 proximate to the aft bearing surface 435. FIG. 5 is an isometric view of the Z-crank 130 configured in accordance with an embodiment of the invention. In one aspect of this embodiment, the Z-crank 130 can include a forward splined portion 531 positioned proximate to the forward bearing surface 434, and an aft splined portion 532 positioned proximate to the aft bearing surface 435. The splined portions illustrated in FIG. 5 can be utilized to accommodate axial movement of the Z-crank 130 relative to other parts that engage with the splined portions. For example, referring to FIG. 3 above, axial movement of the support plate 140 causes the Z-crank 130 to move fore and aft along its rotational axis 131. If the Z-crank aft splines 532 are engaged with, for example, a rotational member or other coupling that is axially (but not rotationally) fixed relative to the Z-crank 130, then the aft splined portion 532 permits the Z-crank to move fore and aft relative to such a fixed coupling. Similarly, if the forward splined portion 531 is engaged with another rotational member that is also axially fixed relative to the Z-crank 130, then the forward splined portion 531 accommodates the relative axial movement between the Z-crank 130 and the forward member. Thus, as the Z-crank/motion converter assembly moves fore and aft along the rotational axis 131 of the Z-crank 130, the splined portions on the forward and aft end of the Z-crank 130 can accommodate the relative axial motion between the Z-crank and any mating features. In other embodiments, other features can be utilized to accommodate the relative motion of the Z-crank/motion converter assembly as the Z-crank moves fore and aft to change the compression ratio in the cylinders 110 (FIG. 1). In yet another aspect of this embodiment, the Z-crank 130 can include a counter-weight 534 laterally offset from the Z-crank rotational axis 131. If required or desirable, the counter-weight 534 can be used to dynamically balance the motion converter/Z-crank assembly. FIG. 6 illustrates exploded isometric views of the motion converter 120 and the Z-crank 130 configured in accordance with embodiments of the invention. The embodiments illustrated in FIG. 6 are merely representative and, accordingly, and are not intended to limit the present invention to the configurations shown. Accordingly, in other embodiments, other components can be utilized to construct and practice the motion converter 120 and the Z-crank 130 of the present invention. In the illustrated embodiment, the Z-crank 130 can include an upper portion 634 mated to a lower portion 636 with a taper pin 637. Prior to mating, the upper Z-crank portion 634 can receive a thrust bearing 638 and can be inserted through the motion converter bore 422. After the upper Z-crank portion 634 is inserted through the motion converter bore 422, it can receive another thrust bearing 638 and be inserted into the lower Z-crank portion 636, thereby rotatably capturing the motion converter 120 on the Z-crank 130. In another aspect of this embodiment, the motion converter 120 can include needle bearings 628 received in the motion converter bore 422. The needle bearings 628 facilitate rotational motion of the Z-crank 130 relative to the motion converter 120. In other embodiments, other bearings in other configurations can be used to provide rotational freedom of the Z-crank 130 relative to the motion converter 120. FIG. 7 is a partially exploded isometric view of the reaction control shaft 150 shown in FIGS. 1-4 above. In one aspect of this embodiment as mentioned above, the reaction control shaft gear 266 can be fixedly attached to a lower end of the reaction control shaft 150 to control the rotational motion of the reaction control shaft 150 about its rotational axis 151. As shown to good effect in FIG. 7, the offset bearing surface 351 is cylindrical in cross-section and has a centerline axis 751 that is offset relative to the rotational axis 151 of the reaction control shaft 150. In one aspect of this embodiment, this offset is necessary to facilitate the nutational motion of the motion converter 120. In another aspect of this embodiment, the reaction control shaft 150 can include counter-weights 756 which can be machined or otherwise conformed to rotationally balance the reaction control shaft 150 about its rotational axis 151. In a further aspect of this embodiment, the reaction control bearing 454 includes a ball bearing 752 and a retaining ring 754. The ball bearing 752 is received on the reaction control bearing 352 at an angle relative to the reaction control bearing bore 454. In a further aspect of this embodiment, the angle of the ball bearing 752 accommodates the nutational movement of the motion converter 120 relative to the reaction control shaft 150 as the Z-crank 130 rotates. In addition, the ball bearing 752 allows the reaction control bearing 352 to rotate relative to the reaction control bearing bore 424 (FIG. 4) of the motion converter 120. This relationship between the ball bearing 752, the reaction control shaft 150, and the motion converter 120 can be seen with reference to FIG. 3. The retaining ring 754 can be threadably installed onto the reaction control bearing 352 to retain the ball bearing 752. Prior to assembly of the reaction control shaft 150 (for example, prior to installing the first counterweight 756), the bearing surface 351 of the reaction control shaft 150 is inserted through the reaction control bearing bore 454 of the reaction control bearing 352. The first counterweight 755 can then be installed on the reaction control shaft 150. The foregoing discussion describes one embodiment of the present invention for restricting rotational movement of the motion converter 120 as it nutates relative to the Z-crank rotational axis 131 (FIGS. 1-3). In other embodiments, other apparatuses and methods can be utilized to restrict this rotational movement without departing from the spirit or scope of the present invention. Specifically, other apparatuses and methods can be utilized to restrict this rotational movement while still enabling the variable compression features of the present invention. One such embodiment is described in greater detail below with reference to FIG. 8 and on. FIG. 8 is a partially cutaway isometric view of an axial piston apparatus 800 having an anti-rotation gear train 860 configured in accordance with another embodiment of the invention. Although the axial piston apparatus 800 of FIG. 8 includes six pistons 812 and associated hardware, this number is in no way limiting and, in other embodiments, the axial piston apparatus 800 can include more or fewer pistons 812. Similarly, although the illustrated embodiment may depict a two-stroke diesel engine configuration, in other embodiments, the anti-rotation gear train 860 and associated features can be utilized with other axial piston apparatuses (e.g., 4-stroke engine or pump apparatuses) configured in accordance with the present disclosure. In the illustrated embodiment, a forward splined portion 831 of a Z-crank 830 protrudes beyond an engine block or housing 801. As discussed above, the forward splined portion 831 can be utilized to drive a camshaft for, among other things, actuating inlet poppet valves for providing fuel mixture to combustion chambers in the cylinders 810. FIG. 9 is a side elevation view of the axial piston apparatus 800 of FIG. 8 with the housing 801 removed to better illustrate aspects of the anti-rotation gear train 860 configured in accordance with an embodiment of the invention. As shown in FIG. 9, the anti-rotation gear train 860 replaces the reaction control shaft 150 described above and serves the same function, namely, to restrict rotational movement of a motion converter 920. In one aspect of this embodiment, the anti-rotation gear train 860 (the “gear train 860”) includes a fixed gear 862, a first planetary gear 864, a second planetary gear 866, and a motion converter gear 868. The fixed gear 862 can be fixedly mounted to a lower portion of the Z-crank 830 and meshed with the first planetary gear 864. In one embodiment, the fixed gear 862 and the planetary gear 864 can be straight gears. In other embodiments, these gears can have other configurations. In another aspect of this embodiment, the first planetary gear 864 can be fixedly mounted on a common shaft with the second planetary gear 866. Accordingly, the first and second planetary gears 864 and 866 are fixed relative to each other and rotate about a common axis 835. In a further aspect of this embodiment, the second planetary gear 866 can be beveled or tapered to mesh with the correspondingly tapered motion converter gear 868. The motion converter gear 868 can be rotatably mounted (e.g., with needle or roller bearings) to a bearing surface 832 of the Z-crank 830. Further, the motion converter gear 868 can be fixedly attached to the motion converter 920. An example of the operation of the gear train 860 will now be explained in accordance with an embodiment of the invention in which a combustion force F drives the pistons 812 to provide shaft-power output from the Z-crank 830. In this embodiment, combustion gases move the pistons 812 causing the motion converter 920 to wobble or nutate relative to the Z-crank axis 931. As the motion converter 920 nutates, it causes the Z-crank 830 to rotate about its rotational axis 931. Simultaneously, however, the gear train 860 prevents the motion converter 920 from rotating relative to the nutational axis 833. Rotation of the motion converter 920 is prevented by the motion converter gear 868 which is fixed relative to the motion converter 920 and engaged with the second planetary gear 866. The second planetary gear 866 is fixed relative to the first planetary gear 864 which in turn meshes with the fixed gear 862. In a further aspect of this embodiment, the ratio of the fixed gear 862 to the first planetary gear 864 should be equal to the ratio of the motion converter gear 868 to the second planetary gear 866. When this ratio is met, the gear train 860 as illustrated in FIG. 9 can at least substantially prevent significant rotation of the motion converter 920. If the motion converter 920 is allowed to rotate freely about the nutation axis 833 as the Z-crank 830 rotates, then the motion converter 920 cannot convert linear motion of the pistons 812 into torque at the Z-crank 830 nor, conversely, can the motion converter 920 convert torque from the Z-crank 830 into linear motion of the pistons 812. Accordingly, in an ideal situation, the motion converter 920 will move in a purely nutational motion without any substantial rotation. FIGS. 10 and 11 are isometric and top views, respectively, illustrating further aspects of the axial piston apparatus 800 discussed above with reference to FIG. 9. FIG. 12 is an exploded isometric view of a piston/connecting rod assembly configured in accordance with an embodiment of the invention. In one aspect of this embodiment, the piston/connecting rod assembly shown in FIG. 12 can be at least generally similar to the double-articulating piston/connecting rod assemblies described above with reference to FIG. 2. For example, the upper wrist pin 218 can be received in an upper trunnion 1201 which pivotally connects the upper end (i.e., the “small end”) of the connecting rod 114 to the piston 112. Similarly, the lower wrist pin 216 can be received in a lower trunnion 1201 which pivotally connects the lower end (i.e., the “big end”) of the connecting rod 114 to a corresponding motion converter (e.g., the motion converter 120 or 920 described above). To accommodate rotation of the wrist pins about at least two axes, the trunnions 1201, 1202 can include a spherical surface and opposing trunnion pins. The spherical surface and opposing trunnion pins can be received within an interior portion of mating spherical shell bearings to accommodate rotation about a trunnion pin axis 1211 as well as rotation about a wrist pin axis 1213. A key or similar feature can be used to register the spherical shell bearings in the corresponding ends of the connecting rod 114. As will appreciated by those of ordinary skill in the relevant art, other methods and apparatuses can be utilized to pivotally connect the piston 112 to the connecting rod 14, and the connecting rod 14 to a corresponding motion converter, in accordance with the present disclosure. The embodiment illustrated in FIG. 12 represents only one such method. FIG. 13 is an isometric view of an axial piston apparatus 1300 that is at least generally similar in structure and function to the axial piston apparatus 100 described above with reference to FIG. 1 through 5. In one aspect of this embodiment, however, the axial piston apparatus 1300 includes one-piece piston/connecting rod assemblies 1313. The one-piece piston/connecting rod assemblies 1313 can include a piston portion 1312 and a connecting rod portion 1314. The piston portion 1312 can have a spherical cross-section to accommodate slight angular motion of the connecting rod portion 1314 relative to the cylinder (not shown) resulting from the nutational movement of the motion converter 120. Such one-piece piston/connecting rod assemblies 1313 may, in certain embodiments, reduce the overall cost of the axial piston apparatus 1300 relative to other configurations. As shown in FIG. 14, for example, the one-piece piston/connecting rod assembly 1313 necessarily has a lower part count than a piston assembly having the double-articulated connecting rod 114. Various aspects of the axial piston apparatuses described above can be combined to create engine and/or pump configurations in addition to those described above. For example, various dual-Z-crank configurations can be achieved in accordance with the present disclosure. Such dual-Z-crank configurations can include pistons facing towards each other in pairs sharing common cylinders. Alternatively, such configurations can include opposed cylinders facing outwardly relative to each other similar to two axial piston apparatuses positioned back-to-back. Such configurations may be advantageously self-counterbalancing and not require further counterbalancing via weights, etc. FIG. 15 is an isometric view of an axial piston apparatus 1500 having a first axial piston apparatus 1501 operably coupled to a second axial piston apparatus 1502 in a back-to-back relationship. In one aspect of this embodiment, the combined apparatuses include two Z-cranks which are coupled together and provide shaft-power output via an output gear 1530. Various mechanical features of the axial piston apparatus 1500 illustrated in FIG. 15 can be at least generally similar in structure and function to their corresponding counterparts of the axial piston apparatus 100 described above. In addition, however, the axial piston apparatus 1500 can include a Z-crank actuator to simultaneously (or independently) move the coupled Z-cranks back and forth relative to each other on their rotational axis. Such movement can vary the compression in one or both sets of cylinders (not shown) to provide the variable compression aspects of the invention described above. When two complete axial piston apparatuses are coupled back-to-back as illustrated in FIG. 15, the reaction forces of the two motion converters can cancel out. Accordingly, counterbalancing of such apparatuses may not be required when the two opposing Z-cranks are in directly opposing phases relative to each other. FIG. 16 illustrates a side elevation view and a top view of the axial piston apparatus 1500 of FIG. 15. As shown in the side elevation view, the opposing Z-cranks 1530 are coupled together as are the corresponding reaction control shafts 1550. In a further aspect of this embodiment, the opposed motion converters 1520 can be in phase for four-stroke engine applications and at least slightly out of phase for two-stroke engine applications and compressor or pump applications. Varying the phase for two-stroke engine applications and compressor or pump applications may be advantageous, in selected embodiments, to accommodate the intake port or outlet port timing arrangements in the cylinders of such applications. In other embodiments, however, the opposing motion converters 1520 can have other phase timings with respect to each other without departing from the spirit or scope of this disclosure. FIG. 17 is an isometric view of an axial piston apparatus 1700 having an opposed piston configuration in accordance with yet another embodiment of the invention. In one aspect of this embodiment, opposing pistons 1712 linearly reciprocate in common cylinders (cylinders are not shown in FIG. 17). The axial piston apparatus 1700 can have coupled Z-cranks 1730 and coupled reaction control shafts 1750 similar to the axial piston apparatus 1500 shown in FIG. 15. In the embodiment depicted in FIG. 17, however, the variable compression features described above can be implement by moving one or both of the opposing Z-cranks toward or away from each other to accordingly change the working volumes in the corresponding cylinders. In a further aspect of this embodiment, the axial piston apparatus 1700 can be configured as a two-stroke engine utilizing exhaust and intake ports instead of poppet-type valves. In this embodiment, one or more exhaust ports can be positioned toward one end of a cylinder and one or more intake ports can be positioned toward the other end. The opposed Z-cranks 1730 may then be configured to operate slightly out of phase so that the exhaust ports on one end are open before the intake ports open on the other end. Such sequential timing may be desirable to maintain the momentum and/or flow direction of the fluid moving into and out of the corresponding cylinder volume. In a further embodiment, such an engine configuration may be supercharged or turbocharged to provide additional advantages depending on the particular application. FIG. 18 illustrates a side elevation view and a top view of the axial piston apparatus 1700 of FIG. 17 to further illustrate aspects of this embodiment. The foregoing description of the embodiments of the invention are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed herein. While specific embodiments of, and examples for, the invention are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the invention, as those of ordinary skill will recognize. For example, although certain functions may be described in the present disclosure in any particular order, and alternate embodiments, these functions can be performed in a different order or, alternatively, these functions may be performed substantially concurrently. In addition, the teachings of the present disclosure can be applied to other systems, not only the representative axial engine, compressor, pump systems described herein. Further, various aspects of the invention described herein can be combined to provide yet other embodiments. Accordingly, aspects of the invention can be modified, if necessary or desirable, to employ the systems, functions, and concepts of conventional engine, pump and/or compressor apparatuses to provide yet further embodiments of the invention. These and other changes can be made to the invention in light of the above-detailed description. Accordingly, the actual scope of the invention encompasses the disclosed embodiments described above and all equivalent ways of practicing or implementing the invention. Unless the context clearly requires otherwise, throughout this disclosure the words “comprise,” “comprising,” and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of “including, but not limited to.” Words using the singular or plural number also include the plural or singular number, respectively. Additionally, the words “herein,” “above,” “below,” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application. The following examples represent additional embodiments of axial piston apparatuses configured in accordance with the present disclosure. | <SOH> BACKGROUND OF THE INVENTION <EOH>The following disclosure relates generally to machines and apparatuses having axial piston arrangements and, more particularly, to apparatuses and methods for converting reciprocating linear motion of one or more pistons into rotary motion of an associated shaft oriented in parallel to the piston motion. Various apparatuses are known that convert movement of a working fluid within a changeable cylinder volume into rotary motion of an input/output shaft. Conventional internal combustion engines, compressors, and pumps are just a few of such apparatuses. In conventional arrangements, the pistons are connected via connecting rods to a crankshaft that rotates on an axis oriented perpendicular to the direction of travel of the piston. The theoretical advantages of the axial piston arrangement have been well understood for many years, but no prior effort has succeeded in the marketplace. The primary difficulty in implementing an axial piston engine is in the means provided for preventing rotation of the motion converter, or as commonly referred to, the “wobble plate.” | <SOH> BRIEF SUMMARY OF THE INVENTION <EOH>It is an object of the invention to reduce friction losses in internal combustion engines and the like. Another object of the invention to provide for variable compression ratio in internal combustion engines. A further object of the invention is to provide a piston motion that is harmonic in nature and can be readily balanced and thereby reduce vibration. It is an additional object of the invention to provide an improved means for preventing the rotation of the motion converter in an axial piston machine. Another object of the invention is to provide a means for preventing the rotation of the connecting rods in an axial piston machine. Yet another object of the invention is to provide for a one-piece or rigidly attached piston and connecting rod in an axial piston machine. | 20040121 | 20051129 | 20050721 | 96367.0 | 0 | LAZO, THOMAS E | AXIAL PISTON MACHINES | SMALL | 0 | ACCEPTED | 2,004 |
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10,762,182 | ACCEPTED | Explosive pipe severing tool | A pipe severing tool is arranged to align a plurality of high explosive pellets along a unitizing support structure whereby all explosive pellets are inserted within or extracted from a tubular housing as a singular unit. Electrically initiated exploding wire detonators (EBW) are positioned at opposite ends of the tubular housing for simultaneous detonation by a capacitive firing device. The housing assembly includes a detachable bottom nose that permits the tool to be armed and disarmed without disconnecting the detonation circuitry. Because the tool is not sensitive to stray electrical fields, it may be transported, loaded and unloaded with the EBW detonators in place and connected. | 1-20. (canceled) 21. An apparatus for explosively severing a length of pipe, said apparatus comprising: (a) a tubular housing having an internal barrel space for receiving an axial column of explosive material between opposite distal ends; (b) first and second detonator socket housings disposed at said opposite distal ends for substantially simultaneously detonating said column of explosive material at said opposite ends; (c) resilient bias means for resiliently translating a first socket housing along said barrel space toward a second socket housing; (d) electrically connected detonators in said socket housings; and, (e) an electrically connected firing device electrically connected to said detonators, said second socket housing and corresponding electrically connected detonator being selectively removable from said housing for inserting said column of explosive material into said barrel space. 22. An apparatus as described by claim 21 wherein said axial column of explosive is unitized about a substantially central rod structure having a length greater than said axial column of explosive. 23. An apparatus as described by claim 21 wherein one distal end of said tubular housing is environmentally sealed by said second socket housing that is selectively removable from said tubular housing to load a column of explosive material into said internal barrel. 24. An apparatus as described by claim 23 wherein said second socket housing further includes an aperture for receiving a length of said central rod structure greater than a length of said axial column of explosive. 25. An apparatus as described by claim 21 wherein said first socket housing is resiliently biased by a spring along the length of said internal barrel to compressively confine said column of explosive material between said socket housings. 26. An apparatus as described by claim 21 wherein said axial column of explosive material comprises a plurality of high explosive pellets aligned about said central rod. 27. A method of severing a length of pipe comprising the steps of: providing a tubular barrel space for assembling a column of highly explosive material; providing exploding wire detonators at opposite ends of said tubular barrel space; providing a capacitive firing device for selectively igniting said detonators substantially simultaneously; assembling a column of highly explosive material within said tubular barrel space; resiliently engaging opposite ends of said explosive material column with said exploding bridge wire detonators; positioning said tubular barrel within the internal flow bore of a pipe at a predetermined location along the length of said flow bore; and, electrically initiating said detonator means. 28. A method as described by claim 27 wherein said column of explosive material is assembled externally of said tubular barrel and positioned into said barrel space as an integral unit; 29. A method as described by claim 27 wherein a plurality of high explosive pellets are assembled in said barrel space as a column. 30. A method of severing a string of pipe extending within a well bore from a wellhead site, said method comprising the steps of: providing a severing tool at a wellhead site, said severing tool having an internal barrel space between opposite distal ends within a substantially tubular housing; providing electrically actuated detonators at said opposite distal ends; electrically connecting said detonators to an electrical firing device for substantially simultaneous ignition of said detonators; delivering said severing tool to said wellhead site with said detonators electrically connected; depositing a column of explosive material in said internal barrel space between said exploding bridge wire detonators at said wellhead site without disconnecting said detonators; positioning said severing tool at a predetermined location within a string of pipe suspended from said wellhead site; and, detonating said column of explosive material by an electrical signal to said firing device. 31. A method as described by claim 30 wherein said column of explosive material is assembled as a singular unit externally of said barrel space and deposited in said barrel space as a singular unit. 32. A method as described by claim 31 wherein an unexploded column of explosive material within said barrel space may be removed from said barrel space as a singular unit. 33. A method as described by claim 30 wherein said column of explosive material is deposited in said barrel space as a serial plurality of pellets. | BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the earthboring arts. More particularly, the invention relates to methods and devices for severing drill pipe, casing and other massive tubular structures by the remote detonation of an explosive cutting charge. 2. Description of Related Art Deep well earthboring for gas, crude petroleum, minerals and even water or steam requires tubes of massive size and wall thickness. Tubular drill strings may be suspended into a borehole that penetrates the earth's crust several miles beneath the drilling platform at the earth's surface. To further complicate matters, the borehole may be turned to a more horizontal course to follow a stratification plane. The operational circumstances of such industrial enterprise occasionally presents a driller with a catastrophe that requires him to sever his pipe string at a point deep within the wellbore. For example, a great length of wellbore sidewall may collapse against the drill string causing it to wedge tightly in the well bore. The drill string cannot be pulled from the well bore and in many cases, cannot even be rotated. A typical response for salvaging the borehole investment is to sever the drill string above the obstruction, withdraw the freed drill string above the obstruction and return with a “fishing” tool to free and remove the wedged portion of drill string. When an operational event such as a “stuck” drill string occurs, the driller may use wireline suspended instrumentation that is lowered within the central, drill pipe flow bore to locate and measure the depth position of the obstruction. This information may be used to thereafter position an explosive severing tool within the drill pipe flow bore. Typically, an explosive drill pipe severing tool comprises a significant quantity, 800 to 1,500 grams for example, of high order explosive such as RDX, HMX or HNS. The explosive powder is compacted into high density “pellets” of about 22.7 to about 38 grams each. The pellet density is compacted to about 1.6 to about 1.65 gms/cm3 to achieve a shock wave velocity greater than about 30,000 ft/sec, for example. A shock wave of such magnitude provides a pulse of pressure in the order of 4×106 psi. It is the pressure pulse that severs the pipe. In one form, the pellets are compacted at a production facility into a cylindrical shape for serial, juxtaposed loading at the jobsite as a column in a cylindrical barrel of a tool cartridge. Due to weight variations within an acceptable range of tolerance between individual pellets, the axial length of explosive pellets fluctuates within a known tolerance range. Furthermore, the diameter-to-axial length ratio of the pellets is such that allows some pellets to wedge in the tool cartridge barrel when loaded. For this reason, a go-no-go type of plug gauge is used by the prior art at the end of a barrel to verify the number of pellets in the tool barrel. In the frequent event that the tool must be disarmed, the pellets may also wedge in the barrel upon removal. A non-sparking depth-rod is inserted down the tool barrel to verify removal of all pellets. Extreme well depth is often accompanied by extreme hydrostatic pressure. Hence, the drill string severing operation may need to be executed at 10,000 to 20,000 psi. Such high hydrostatic pressures tend to attenuate and suppress the pressure of an explosive pulse to such degree as to prevent separation. One prior effort by the industry to enhance the pipe severing pressure pulse and overcome high hydrostatic pressure suppression has been to detonate the explosive pellet column at both ends simultaneously. Theoretically, simultaneous detonations at opposite ends of the pellet column will provide a shock front from one end colliding with the shock front from the opposite end within the pellet column at the center of the column length. On collision, the pressure is multiplied, at the point of collision, by about 4 to 5 times the normal pressure cited above. To achieve this result, however, the detonation process, particularly the simultaneous firing of the detonators, must be timed precisily in order to assure collision within the explosive column at the center. Such precise timing is typically provided by means of mild detonating fuse and special boosters. However, if fuse length is not accurate or problems exist in the booster/detonator connections, the collision may not be realized at all and the device will operate as a “non-colliding” tool with substantially reduced severing pressures. The reliability of state-of-the-art severing tools is further compromised by complex assembly and arming procedures required at the well site. With those designs, regulations require that explosive components (detonator, pellets, etc.) must be shipped separately from the tool body. Complete assembly must then take place at the well site under often unfavorable working conditions. Finally, the electric detonators utilized by state-of-the-art severing tools are not as safe from the electric stray currents and RF energy points of view, further complicating the safety procedures that must be observed at the well site. SUMMARY OF THE INVENTION The pipe severing tool of the present invention comprises an outer housing that is a thin wall metallic tube of such outside diameter that is compatible with the drill pipe flow bore diameter intended for use. The upper end of the housing tube is sealed with a threaded plug having insulated electrical connectors along an axial aperture. The housing upper end plug is externally prepared to receive the intended suspension string such as an electrically conductive wireline bail or a continuous tubing connecting sub. The lower end of the outer housing tube is closed with a tubular assembly that includes a stab fit nose plug. The nose plug assembly includes a relatively short length of heavy wall tube extending axially out from an internal bore plug. The bore plug penetrates the barrel of the housing tube end whereas the tubular portion of the nose plug extends from the lower end of the housing tube. The bore plug is perimeter sealed by high pressure O-rings and secured by a plurality of set screws around the outside diameter of the outer housing tube. The tubular portion of the nose plug provides a closed chamber space for enclosing electrical conductors. The bore plug includes a tubular aperture along the nose plug axis that is a load rod alignment guide. Laterally of the load rod alignment guide is a socket for an exploding bridge wire (EBW) detonator or an exploding foil initiator (EFI). Within the upper end of the outer housing barrel is an inner tubular housing for a electronic detonation cartridge having a relatively high discharge voltage, 5,000 v or more, for example. Below the inner tubular housing is a cylindrical, upper detonator housing. The upper detonator housing is resiliently separated from the lower end of the inner tubular housing by a suitable spring. The upper detonator housing includes a receptacle socket 31 for an exploding bridge wire (EBW) detonator. The axis for the upper detonator receptacle socket is laterally offset from the outer housing barrel axis. Preferably, the severing tool structure is transported to a working location in a primed condition with upper and lower EBW detonators connected for firing but having no high explosive pellets placed between the EBW detonators. At the appropriate moment, the nose plug assembly is removed from the bottom end of the outer housing and a load rod therein removed. The upper distal end of the load rod includes a circumferential collar such as a snap ring. The opposite end of the load rod is visually marked to designate maximum and minimum quantities of explosive aligned along the load rod. Explosive pellets for the invention are formed as solid cylinder sections having an axial aperture. The individual pellets are stacked along the load rod with the load rod penetrating the axial aperture. The upper distal end collar serves as a stop limit for the pellets which are serially aligned along the rod until the lower face of the lowermost pellet coincides with the max/min indicia marking. A restriction collar such as a resilient O-ring is placed around the loading rod and tightly against the bottom face of the lowermost explosive pellet. The rod and pellet assembly are inserted into the outer housing barrel until the uppermost pellet face contiguously engages the upper detonator housing. The rod guide aperture in the nose plug is then assembled over the lower distal end of the load rod and the lower detonator brought into contiguous engagement with the lowermost pellet face. The assembly is then further compressed against the loading spring between the inner tubular housing and the upper detonator housing until abutment between the nose plug shoulder and the lower distal end of the outer housing tube. In the event that the invention severing tool must be disarmed, all pellets may be removed from the housing barrel as a singular unit about the load rod. This is accomplished by removing the lower nose plug which exposes the lower end of the load rod. By grasping and pulling the load rod from the housing barrel, all pellets that are pinned along the load rod below the upper distal end collar are drawn out of the housing tube with the rod. BRIEF DESCRIPTION OF THE DRAWINGS Relative to the drawings wherein like reference characters designate like or similar elements or steps through the several figures of the drawings: FIG. 1 is a sectional view of the invention as assembled without an explosive charge for transport; FIG. 2 is a sectional view of the invention with the bottom nose piece detached from the main assembly housing; FIG. 3 is a sectional view of an assembled, explosive pellet unit; FIG. 4 is a sectional view of the invention with the explosive pellet unit combined with the main assembly housing but the bottom nose piece detached therefrom; FIG. 5 is a sectional view of the invention in operative assembly with an explosive pellet unit. DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the FIG. 1 cross-sectional view of the invention 10, a tubular outer housing 12 having an internal bore 14 is sealed at an upper end by a plug 16. The plug 16 includes an axial bore 18 and an electrical connector 20 for routing detonation signal leads 22. A boss 17, projecting from the base of the plug, is externally threaded for the attachment of the desired suspension string such as an electrical wireline or service tubing. An inner housing tube 24 is secured to and extends from the upper end plug 16 into the internal bore 14 of the outer housing 12. The inner housing tube 24 encloses a capacitive firing cartridge 26. Below the inner housing 24 is an upper detonator housing 28. A coil spring 30 links the upper detonator housing 28 to the inner housing tube 24. An exploding bridge wire (EBW) detonator or exploding foil initiator (EFI) 32 is seated within a receptacle socket formed in the upper detonator housing 28 laterally of the housing axis. Electrical conduits 34 connect the capacitive firing cartridge 26 to to the EBW detonator or EFI 32. An exploding bridge wire (EBW) detonator comprises a small quantity of moderate to high order explosive that is detonated by the explosive vaporization of a metal filament or foil (EFI) due to a high voltage surge imposed upon the filament. A capacitive firing cartridge is basically an electrical capacitator discharge circuit that functions to to abruptly discharge with a high threshold voltage. Significantly, the EBW detonator or EFI is relatively insensitive to static or RF frequency voltages. Consequently, the capacitive firing circuit and EBW or EFI function cooperatively to provide a substantial safety advantage. An unusually high voltage surge is required to detonate the EBW detonator (or EFI) and the capacitive firing cartridge delivers the high voltage surge in a precisely controlled manner. The system is relatively impervious to static discharges, stray electrical fields and radio frequency emissions. Since the EBW and EFI detonation systems are, functionally, the same, hereafter and in the attached invention claims, reference to an EBW detonator is intended to include and encompass an EFI. The lower end of the outer housing tube 12 is operatively opened and closed by a nose plug 40. The nose plug 40 comprises a plug base 42 having an O-ring fitting within the lower end of the outer housing bore 14. The plug base 42 may be secured to the outer housing tube 12 by shear pins or screws 44 to accomodate a straight push assembly. Projecting from the interior end of the plug base is a guide tube boss 46 having an axial throughbore 48 and a receptacle socket 50 for a detonator cap 66. Projecting from the exterior end of the plug base 42 is a heavy wall nose tube 52 having a nose cap 54. The nose cap 54 may be disassembled from the nose tube 52 for manual access into the interior bore 56 of the nose tube 52. Detonation signal conductor leads 58 are routed from the firing cartridge 26, through the upper detonator housing and along the wall of housing bore 14. A conductor channel 60 routes the leads 58 through the nose plug base 42 into the nose tube interior 56. This nose tube interior provides environmental protection for electrical connections 62 with conductor leads 64 from the lower EBW detonator 66. Although the electrical connections of both EBW detonators 32 and 66 are field accessible, it is a design intent for the invention to obviate the need for field connections. Without explosive pellet material in the outer housing bore 14, EBW 20 detonators 32 and 66 are the only explosive material in the assembly. Moreover, the separation distance between the EBW detonators 32 and 66 essentially eliminates the possibility of a sympathetic detonation of the two detonators. Consequently, without explosive material in the tubing bore 14, the assembly as illustrated by FIG. 1 is safe for transport with the EBW detonators 32 and 66 connected in place. The significance of having a severing tool that requires no detonator connections at the well site for arming cannot be minimized. Severing tools are loaded with high explosive at the well site of use. Often, this is not an environment that contributes to the focused, intellectual concentration that the hazardous task requires. Exacerbating the physical discomfort is the emotional distraction arising from the apprehension of intimately manipulating a deadly quantity of highly explosive material. Hence, the well site arming procedure should be as simple and error-proof as possible. Complete elimination of all electrical connection steps is most desirable. The load rod 70, best illustrated by FIGS. 2, 3 and 4, is preferably a stiff, slender shaft having an end retainer 72 such as a “C” clip or snap ring. Preferably, the shaft is fabricated from a non-sparking material such as wood, glass composite or non-ferrous metal. Individual high explosive “pellets” 74 are cylindrically formed with a substantially uniform outer perimeter OD and a substantially uniform ID center bore. The term “pellets” as used herein is intended to encompass all appropriate forms of explosive material regardless of the descriptive label applied such as “cookies”, “wafers”, or “charges”. The axial length of the pellets may vary within known limits, depending on the exact weight quantity allocated to a specific pellet. The pellets are assembled as a serial column over the rod 70 which penetrates the pellet center bore. A prior calculation has determined the maximum and minimum cumulative column length depending on the the known weight variations. This maximum and minimum column length is translated onto the rod 70 as an indicia band 76. The maximum and minimum length dimensions are measured from the rod end retainer 72. The OD of the end retainer 72 is selected to be substantially greater than the ID of the pellet center bore. Hence the pellets cannot pass over the end retainer and can slide along the rod 70 length no further than the end retainer. When loading the tool with explosive in the field, the correct quantity of explosive 74 will terminate with a lower end plane that coincides within the indicia band 76. An elastomer O-ring 78 constricted about the shaft of rod 70 compactly confines the pellet assembly along the rod length. A lower distal end portion 79 of the rod extends beyond the indicia band 76 to penetrate the guide bore 48 of the bore plug base 42 when the bottom nose plug 40 is replaced after an explosive charge has been positioned. This rod extension allows the high explosive to be manually manipulated as a singular, integrated unit. In full visual field, the explosive charge is assembled by a columned alignment of the pellets over the penetrating length of the rod. When the outside surface plane of the last pellet in the column aligns within the indicia band 76, the lower end retainer 78 is positioned over the rod and against the last pellet surface plane to hold the column in tight, serial assembly. Using the rod extension 79 as a handle, the explosive assembly is axially inserted into the housing bore 14 until contiguous contact is made with the lower face of the upper detonator housing 28. One of the synergistic advantages to the unitary rod loading system of the invention is use of lighter, axially shorter pellets, i.e. 22.7 gms. These lighter weight pellets enjoy a more favoraable shipping classification (UN 1.4S) than that imposed on heavier, 38 gm pellets (UN 1.4D). In a prior art severing tool, the lighter weight pellets would be avoided due to “cocking” in the tool barrel 14 during loading. The loading rod system of the present invention substantially eliminates the “cocking” problem, regardless of how thin the pelleet is. With the explosive assembly in place, the lower end of the housing is closed by placement of the nose plug 40 into the open end of the housing. The rod end projection 79 penetrates the guide bore 48 as the plug base 42 is pushed to an internal seal with the housing bore 14. To assure intimate contact of the opposite end EBW detonators 32 and 66 with the respective adjacent ends of the explosive assembly, the upper detonator housing 28 is displaced against the spring 30 to accommodate the specified length of the explosive column. Accordingly, when the nose plug 40 is seated against the end of the outer housing tube 12, both EBW detonators are in oppositely mutual compression as is illustrated by FIG. 5. The severing tool is now prepared for lowering into a well for the pipe cutting objective Presently applied Explosive Safety Recommendations require the severing tool 10 to be electrically connected to the suspension string i.e. wireline, etc., before arming ballistically. Ballistic arming with respect to the present invention means the insertion of the explosive Pellets 24 into the housing bore 14. On those occasions when the severing tool must be disarmed without discharge, it is only necessary to remove the nose plug 40 and by grasping the rod extension 79, draw the pellets 74 from the tube bore 14 as a single, integrated item. Numerous modifications and variations may be made of the structures and methods described and illustrated herein without departing from the scope and spirit of the the invention disclosed. Accordingly, it should be understood that the embodiments described and illustrated herein are only representative of the invention and are not to be considered as limitations upon the invention as hereafter claimed. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to the earthboring arts. More particularly, the invention relates to methods and devices for severing drill pipe, casing and other massive tubular structures by the remote detonation of an explosive cutting charge. 2. Description of Related Art Deep well earthboring for gas, crude petroleum, minerals and even water or steam requires tubes of massive size and wall thickness. Tubular drill strings may be suspended into a borehole that penetrates the earth's crust several miles beneath the drilling platform at the earth's surface. To further complicate matters, the borehole may be turned to a more horizontal course to follow a stratification plane. The operational circumstances of such industrial enterprise occasionally presents a driller with a catastrophe that requires him to sever his pipe string at a point deep within the wellbore. For example, a great length of wellbore sidewall may collapse against the drill string causing it to wedge tightly in the well bore. The drill string cannot be pulled from the well bore and in many cases, cannot even be rotated. A typical response for salvaging the borehole investment is to sever the drill string above the obstruction, withdraw the freed drill string above the obstruction and return with a “fishing” tool to free and remove the wedged portion of drill string. When an operational event such as a “stuck” drill string occurs, the driller may use wireline suspended instrumentation that is lowered within the central, drill pipe flow bore to locate and measure the depth position of the obstruction. This information may be used to thereafter position an explosive severing tool within the drill pipe flow bore. Typically, an explosive drill pipe severing tool comprises a significant quantity, 800 to 1,500 grams for example, of high order explosive such as RDX, HMX or HNS. The explosive powder is compacted into high density “pellets” of about 22.7 to about 38 grams each. The pellet density is compacted to about 1.6 to about 1.65 gms/cm 3 to achieve a shock wave velocity greater than about 30,000 ft/sec, for example. A shock wave of such magnitude provides a pulse of pressure in the order of 4×10 6 psi. It is the pressure pulse that severs the pipe. In one form, the pellets are compacted at a production facility into a cylindrical shape for serial, juxtaposed loading at the jobsite as a column in a cylindrical barrel of a tool cartridge. Due to weight variations within an acceptable range of tolerance between individual pellets, the axial length of explosive pellets fluctuates within a known tolerance range. Furthermore, the diameter-to-axial length ratio of the pellets is such that allows some pellets to wedge in the tool cartridge barrel when loaded. For this reason, a go-no-go type of plug gauge is used by the prior art at the end of a barrel to verify the number of pellets in the tool barrel. In the frequent event that the tool must be disarmed, the pellets may also wedge in the barrel upon removal. A non-sparking depth-rod is inserted down the tool barrel to verify removal of all pellets. Extreme well depth is often accompanied by extreme hydrostatic pressure. Hence, the drill string severing operation may need to be executed at 10,000 to 20,000 psi. Such high hydrostatic pressures tend to attenuate and suppress the pressure of an explosive pulse to such degree as to prevent separation. One prior effort by the industry to enhance the pipe severing pressure pulse and overcome high hydrostatic pressure suppression has been to detonate the explosive pellet column at both ends simultaneously. Theoretically, simultaneous detonations at opposite ends of the pellet column will provide a shock front from one end colliding with the shock front from the opposite end within the pellet column at the center of the column length. On collision, the pressure is multiplied, at the point of collision, by about 4 to 5 times the normal pressure cited above. To achieve this result, however, the detonation process, particularly the simultaneous firing of the detonators, must be timed precisily in order to assure collision within the explosive column at the center. Such precise timing is typically provided by means of mild detonating fuse and special boosters. However, if fuse length is not accurate or problems exist in the booster/detonator connections, the collision may not be realized at all and the device will operate as a “non-colliding” tool with substantially reduced severing pressures. The reliability of state-of-the-art severing tools is further compromised by complex assembly and arming procedures required at the well site. With those designs, regulations require that explosive components (detonator, pellets, etc.) must be shipped separately from the tool body. Complete assembly must then take place at the well site under often unfavorable working conditions. Finally, the electric detonators utilized by state-of-the-art severing tools are not as safe from the electric stray currents and RF energy points of view, further complicating the safety procedures that must be observed at the well site. | <SOH> SUMMARY OF THE INVENTION <EOH>The pipe severing tool of the present invention comprises an outer housing that is a thin wall metallic tube of such outside diameter that is compatible with the drill pipe flow bore diameter intended for use. The upper end of the housing tube is sealed with a threaded plug having insulated electrical connectors along an axial aperture. The housing upper end plug is externally prepared to receive the intended suspension string such as an electrically conductive wireline bail or a continuous tubing connecting sub. The lower end of the outer housing tube is closed with a tubular assembly that includes a stab fit nose plug. The nose plug assembly includes a relatively short length of heavy wall tube extending axially out from an internal bore plug. The bore plug penetrates the barrel of the housing tube end whereas the tubular portion of the nose plug extends from the lower end of the housing tube. The bore plug is perimeter sealed by high pressure O-rings and secured by a plurality of set screws around the outside diameter of the outer housing tube. The tubular portion of the nose plug provides a closed chamber space for enclosing electrical conductors. The bore plug includes a tubular aperture along the nose plug axis that is a load rod alignment guide. Laterally of the load rod alignment guide is a socket for an exploding bridge wire (EBW) detonator or an exploding foil initiator (EFI). Within the upper end of the outer housing barrel is an inner tubular housing for a electronic detonation cartridge having a relatively high discharge voltage, 5,000 v or more, for example. Below the inner tubular housing is a cylindrical, upper detonator housing. The upper detonator housing is resiliently separated from the lower end of the inner tubular housing by a suitable spring. The upper detonator housing includes a receptacle socket 31 for an exploding bridge wire (EBW) detonator. The axis for the upper detonator receptacle socket is laterally offset from the outer housing barrel axis. Preferably, the severing tool structure is transported to a working location in a primed condition with upper and lower EBW detonators connected for firing but having no high explosive pellets placed between the EBW detonators. At the appropriate moment, the nose plug assembly is removed from the bottom end of the outer housing and a load rod therein removed. The upper distal end of the load rod includes a circumferential collar such as a snap ring. The opposite end of the load rod is visually marked to designate maximum and minimum quantities of explosive aligned along the load rod. Explosive pellets for the invention are formed as solid cylinder sections having an axial aperture. The individual pellets are stacked along the load rod with the load rod penetrating the axial aperture. The upper distal end collar serves as a stop limit for the pellets which are serially aligned along the rod until the lower face of the lowermost pellet coincides with the max/min indicia marking. A restriction collar such as a resilient O-ring is placed around the loading rod and tightly against the bottom face of the lowermost explosive pellet. The rod and pellet assembly are inserted into the outer housing barrel until the uppermost pellet face contiguously engages the upper detonator housing. The rod guide aperture in the nose plug is then assembled over the lower distal end of the load rod and the lower detonator brought into contiguous engagement with the lowermost pellet face. The assembly is then further compressed against the loading spring between the inner tubular housing and the upper detonator housing until abutment between the nose plug shoulder and the lower distal end of the outer housing tube. In the event that the invention severing tool must be disarmed, all pellets may be removed from the housing barrel as a singular unit about the load rod. This is accomplished by removing the lower nose plug which exposes the lower end of the load rod. By grasping and pulling the load rod from the housing barrel, all pellets that are pinned along the load rod below the upper distal end collar are drawn out of the housing tube with the rod. | 20040121 | 20090512 | 20051208 | 80369.0 | 1 | CHAMBERS, TROY | EXPLOSIVE PIPE SEVERING TOOL | UNDISCOUNTED | 1 | CONT-ACCEPTED | 2,004 |
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10,762,261 | ACCEPTED | NAIL HEADS OF A NAIL ROW | The nail heads of a nail row respectively have two symmetrical oblique insert members respectively formed under the front and the rear side, and each oblique insert member has a horizontal plane and an inclined plane connected to each other. Between the horizontal plane and the flat striking portion of the nail head forms a preset thickness strong enough to resist striking. The inclined plane has its outer side edge connected with one side edge of the nail head to form a sharp nailing portion able to be smoothly nailed in a workpiece. The horizontal plane and the inclined plane are combined with the workpiece by mutual engagement, able to combine work pieces together with great stability and firmness. | 1-4. (canceled) 5. A nail row comprising: a plurality of T-shaped nails, each of the plurality of T-shaped nails having: a) a nail shank; b) a nail head connected to the nail shank and having a thickness from a front to a back that is larger than a thickness from a front to a back of the nail shank, the nail head having a flat striking surface located on a top thereof, the nail head and the nail shank have co-planar left and right sides; c) two connecting portions, each of the two connecting portions being located one of the co-planar left and right sides and coated with an adhesive and adjoined to one of the two connecting portions of an adjacent one of the plurality of T-shaped nails; and d) two symmetrical oblique insert members, each of the two symmetrical oblique insert members are formed on a bottom of a protruding portion of the nail head and having: i) a horizontal plane spaced apart from and positioned parallel to the flat striking surface; and ii) an inclined plane connected to the horizontal plane and having a nailing portion formed by an acute angle formed between the inclined plane and one of the left and right sides of the nail head. 6. The nail row according to claim 5, wherein each horizontal plane has a length that is twice a length of each inclined plane. 7. The nail row according to claim 5, wherein the shank of each of the plurality of T-shaped nails has a plurality of oblique recessed lines spaced apart an equal distance and located on the front and back thereof. 8. The nail row according to claim 7, wherein the top of the nail head of one of the plurality of T-shaped nails is located at a height different from a height of the top of the nail head of the adjacent one of the plurality of T-shaped nails, and each of the plurality of oblique recessed lines one of the plurality of T-shaped nails have an end aligning with an end of each of the plurality of oblique recessed lines of the adjacent one of the plurality of T-shaped nails. | BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a nail row, particularly to one whose nail heads are strong enough to endure striking and have great combination force after nailed in workpieces. 2. Description of the Prior Art A conventional nail row 10, as shown in FIGS. 1 and 2, is composed of a plurality of T-shaped nails 11 connected together alongside. Each nail 11 is formed integral with a nail head 111 and a nail shank 112, and the nail head 111 has its topside formed with a striking portion 113 a little wider than the thickness of the nail shank 112 for the striking device (P) of a nailing gun to strike thereon and nail two workpieces together. Further, each nail shank 112 has the surface of its front and rear side respectively provided with a plurality of horizontal recessed lines 114 parallel to the lower plane of the nail head 111. Furthermore, when the nails 11 of the conventional nail row 10 are connected together alongside, the topsides of the nails 11 are respectively positioned at different heights so as to form an oblique nail row 10 with preset inclination, applicable to a nailing gun with an oblique nail cartridge. A horizontal or an oblique nail row 10 has the nail shanks 112 of its nails 11 respectively nailed in workpieces to combine them together, and the horizontal recessed lines 114 of the nail shank 112 are able to increase frictional resistance between the nail shanks 112 and the workpieces so as to enhance their combination strength. However, the horizontal recessed lines 114 of the nail shank 112 are too short to produce enough frictional resistance, unable to obtain an excellent effect of combination. In addition, the nail head 111 of the nail 11 only serves as a striking portion and the plane under the nail head 111 can do nothing but rest on the workpiece 20, both of them unable to help strengthen combination of the workpiece 20. SUMMARY OF THE INVENTION The objective of the invention is to offer the nail heads of a nail row, respectively formed with two symmetrical oblique insert members respectively composed of a horizontal plane and an inclined plane connected with each other so as to increase the striking enduring strength of the nail head and enable the nail to be nailed in a workpiece smoothly with the help of a sharp nailing portion of the nail head, able to nail and combine workpieces together comparatively firmly. BRIEF DESCRIPTION OF DRAWINGS This invention will be better understood by referring to the accompanying drawings, wherein: FIG. 1 is a perspective view of a conventional oblique nail row: FIG. 2 is a cross-sectional view of the conventional oblique nail row: FIG. 3 is a cross-sectional view of the nail of the conventional nail row nailed in workpieces: FIG. 4 is a perspective view of a nail row in the present invention: FIG. 5 is a front view of the nail row in the present invention: FIG. 6 is a cross-sectional view of the nail of the nail row nailed in workpieces in the present invention: and FIG. 7 is a cross-sectional view of two nails of the nail row reversely nailed in workpieces in the present invention. DETAILED DESCRPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of a nail row 30 in the present invention, as shown in FIGS. 4 and 5, is composed of plurality of T-shaped nails 40 connected together alongside. Each nail 40 is formed with a nail head 41 and a nail shank 42, and the distance between the front and the rear side of the nail head 41 is larger than the thickness of the nail shank 42. The nail head 41 has its topside formed with a flat striking surface 411, which has its left and right side respectively extending straight downward to the lowermost end of the nail shank 42 and forming a connecting portion 43 for connecting the nails 40 together to make up the nail row 30 by adhesives. When all the nails 40 of the nail row 30 are connected together alongside, their topsides are respectively positioned at different heights to form an oblique nail row 30 with a preset inclination. The nail head 41 has two symmetrical oblique insert members 412 respectively formed under the protruding portion of its front and rear side. Each oblique insert member 412 is composed of a horizontal plane 4121 and an inclined plane 4122 connected with each other in a ratio of 2:1 in length. The horizontal plane 4121 is parallel to the flat striking portion 411 of the nail head 41, while the inclined plane 4122 forms an acute angle to the vertical side of the nail head 41 to make up a sharp nailing portion 413. In addition, the nail shank 42 has the surface of its front and rear side respectively provided with a plurality of oblique recessed lines 421 spaced apart equidistantly from an upper side to a lower side and parallel to the inclined plane 4122 of the oblique insert member 412 of the nail head 41. In using, as shown in FIGS. 5 and 6, the oblique nail row 30 is fitted in the oblique nail cartridge of a nailing gun and then the nails 40 of the nail row 30 are orderly and respectively struck out and nailed in workpieces 50 by a nail striking device (P) of the nailing gun. Being a plane, the nail striking surface 411 of the nail head 41 can contact with the nail striking device P at a right angle to enable the nail 40 to be impartially nailed into the workpieces 50. In addition, the comparatively long horizontal plane 4121 of the oblique insert member 412 and the nail striking surface 411 of the nail head 41 are formed therebetween with a preset thickness which is strong enough to resist the striking force of the nail striking device (P), preventing the nail head 41 from deformed excessively or broken and enabling the nail 40 to be nailed into the workpieces 50 smoothly. Additionally, when the nail head 41 is struck by the nail striking device (P), the sharp nailing portion 413 of the oblique insert member 412 of the nail head 41 can be deeply stuck in the workpiece 50, and the entire oblique insert member 412 and even the whole nail head 41 can also be firmly stuck into the workpiece 50. Thus, the horizontal plane 4121 and the inclined plane 4122 of the oblique insert member 412 are combined with the workpiece 50 by mutual engagement of different levels, able to let the nail 40 and the workpiece 50 combined together with great stability and firmness. Further, the oblique recessed marks 421 of the nail shank 42 of this invention are respectively longer than the horizontal recessed lines 114 of the conventional nail shank 112, as shown in FIG. 6. Therefore, after the nail 40 is nailed into the workpiece 50, the frictional resistance between them will be enhanced to increase their combination strength. Furthermore, as shown in FIG. 7, in case work pieces 50 need to be nailed together with plural nails 40 of this invention, every two nails 40 can be positioned reversely in the direction and nailed in the workpieces 50, that is, the sharp nailing portions 413 of the oblique insert members 412 of every two nails 40 are positioned reversely and symmetrically to be orderly nailed in the workpieces 50, thus able to enhance the combination strength of the workpieces 50. As can be understood from the above description, this invention has the following advantages. 1. The nail head 41 of the nail 40 has its front and rear side respectively formed with an oblique insert member 412 and a sharp nailing portion 413, and the nail shank 42 of the nail 40 has the surface of its front and rear respectively provided with a plurality of oblique recessed lines 421, increasing the combination strength of the nail 40 with the workpieces 50. 2. The oblique nail row 30 of this invention is applicable to a nailing gun with an oblique nail cartridge, enabling the nailing gun to carry out nailing work at any position of workpieces and facilitating operation of the nailing gun. While the preferred embodiment of the invention has been described above, it will be recognized and understood that various modifications may be made therein and the appended claims are intended to cover all such modifications that may fall within the spirit and scope of the invention. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention This invention relates to a nail row, particularly to one whose nail heads are strong enough to endure striking and have great combination force after nailed in workpieces. 2. Description of the Prior Art A conventional nail row 10 , as shown in FIGS. 1 and 2 , is composed of a plurality of T-shaped nails 11 connected together alongside. Each nail 11 is formed integral with a nail head 111 and a nail shank 112 , and the nail head 111 has its topside formed with a striking portion 113 a little wider than the thickness of the nail shank 112 for the striking device (P) of a nailing gun to strike thereon and nail two workpieces together. Further, each nail shank 112 has the surface of its front and rear side respectively provided with a plurality of horizontal recessed lines 114 parallel to the lower plane of the nail head 111 . Furthermore, when the nails 11 of the conventional nail row 10 are connected together alongside, the topsides of the nails 11 are respectively positioned at different heights so as to form an oblique nail row 10 with preset inclination, applicable to a nailing gun with an oblique nail cartridge. A horizontal or an oblique nail row 10 has the nail shanks 112 of its nails 11 respectively nailed in workpieces to combine them together, and the horizontal recessed lines 114 of the nail shank 112 are able to increase frictional resistance between the nail shanks 112 and the workpieces so as to enhance their combination strength. However, the horizontal recessed lines 114 of the nail shank 112 are too short to produce enough frictional resistance, unable to obtain an excellent effect of combination. In addition, the nail head 111 of the nail 11 only serves as a striking portion and the plane under the nail head 111 can do nothing but rest on the workpiece 20 , both of them unable to help strengthen combination of the workpiece 20 . | <SOH> SUMMARY OF THE INVENTION <EOH>The objective of the invention is to offer the nail heads of a nail row, respectively formed with two symmetrical oblique insert members respectively composed of a horizontal plane and an inclined plane connected with each other so as to increase the striking enduring strength of the nail head and enable the nail to be nailed in a workpiece smoothly with the help of a sharp nailing portion of the nail head, able to nail and combine workpieces together comparatively firmly. | 20040123 | 20050809 | 20050728 | 64835.0 | 0 | SHARP, JEFFREY ANDREW | NAIL HEADS OF A NAIL ROW | SMALL | 0 | ACCEPTED | 2,004 |
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10,762,301 | ACCEPTED | Probe for measuring quality-of-service parameters in a telecommunication network | A measuring probe (S), having the means to access data flows composed of packets transmitted along a path formed by a plurality of equipment in a telecommunication network, and the measurement means (SM) to perform measurements in accordance with the configuration data (BC), and in addition possessing determination means (SD) for determining that one or more transmitted packets form a signalling message, and the signalling means (SS) to determine the configuration data from this signalling message. | 1. A measuring probe (S), having the means to access data flows composed of packets, transmitted along a path formed by a multiplicity of equipment in a telecommunication network, and the measurement means (SM) to perform measurements, in accordance with configuration data (BC), characterised in that in addition it possesses determination means (SD) employed to determine that one or more packets transmitted along the said path form a signalling message, and signalling means (SS) to determine the said configuration data from this signalling message. 2. A measuring probe in accordance with the previous claim 1, in which the said measurements are relative to the said data flow. 3. A measuring probe in accordance with claim 1, in which the said measurement means (SM) are suitable for transmitting measurement reports, containing the said measurements, to a measuring device (M) determined by an identifier contained in the said configuration data. 4. A measuring probe in accordance with claim 3, in which the said measurements are transmitted to the said measuring device (M) by means of a proxy, the data transmitted to the said proxy containing the said identifier. 5. A measuring probe in accordance with claim 1, in which the said means of determination (SD) are suitable for reading a specific label, contained in the said received message, and for determining whether the said received message is a signalling message from this specific label. 6. A measuring probe in accordance with claim 1, in which the said configuration base contains a set of records, each record corresponding to a measurement task and containing in particular: a filter determining the packets on which the measurements must be performed, parameters relating to the method of measurement 7. A measuring probe in accordance with claim 1, in which the said parameters are chosen from a combination of factors including: the time during which the measurements must be performed, sampling data, and a hashing function in particular, a parameter triggering the time-stamping of the packets to be measured, a parameter triggering the identification of the packets to be measured, by means of a hashing function in particular. A parameter triggering the counting of the packets, the method for transmitting the measurements to the measuring device (M). 8. A measuring probe in accordance with claim 3, in which the transmissions with the measuring device (M) are made secure. 9. A measuring probe in accordance with claim 8, in which the means of making secure are transmitted by a signalling message. 10. A measuring probe in accordance with claim 1, also including means to decide on the creation of a new measurement task by the said signalling means (SS), in particular in accordance with a sensitivity indicator associated with the said measuring probe. 11. A measuring probe in accordance with claim 10, in which the decision is also a function of a priority contained in the said received message. 12. A network element, in particular a router, including a measuring probe in accordance with claim 1. 13. A telecommunication network including measuring probes in accordance with claim 1. 14. A telecommunication network in accordance with claim 13, including, in addition, measuring devices (M). | This present invention relates to measuring the characteristic parameters of the equipment traversed by a data flow within a data network, and a telecommunication network in particular. It applies particularly well to measurement of quality-of-service parameters rendered in respect of the data flow passing through this telecommunication network, but could also apply to other characteristics of the equipment such as loading, temperature, the state of queues, and so on, located in the path of these data flows. In fact it is important to have measurements of certain parameters in order to verify the correct operation of one's network, and in particular to ascertain if the quality of service requested by customers is actually being provided. In order to achieve this, there are various known devices in the current state of the art. For example, the Ipanema company markets measuring probes which can be placed at the input of the telecommunication network, as indicated in FIG. 1, in which probes S1 and S2 are connected to the telecommunication network (N). When data flows pass through probes S1 and S2, these measure some parameters and supply these parameters to a measuring device (M). Measuring device (M) transmits information to the probes concerning the parameters they must measure. It can thus configure the data flows on which the measurements must be performed, as well as the periodicity of the measurements, etc. However, such a device suffers from a major problem whenever the telecommunication network consists of several domains, each domain capable of being administered by a different telecommunication operator. The probes can be installed only at the extremities of the domain administered by the telecommunication operator. As soon as we find ourselves in a real environment, meaning one which is composed of several domains, it is no longer possible to obtain end-to-end measurements, since the operator of one domain will generally have access only to the equipment in its own domain, to the exclusion of all the other domains. Moreover, it can be useful to have a measurement not just between the extremities of the network or of the domain, but also between the telecommunication terminals themselves, or even within the different domains or within the equipment traversed by a data flow. This is particularly desirable in the case of telephony terminals on IP (Internet Protocol). In this situation, it does not seem clear how one can ascertain how to install and/or to configure the probes at the customer end, or within the networks traversed. Thus, in order to do this, the entity wishing to perform the measurements must discover or configure the different measuring probes put in place in the different domains of the telecommunication network. The state-of-the-art solution is silent regarding this problem. The aim of this present invention is to propose a solution for the measurement of parameters, in particular of quality-of-service parameters, which is easy to configure, and which does not suffer from the problems of the state-of-the-art solutions. To this end, the subject of the invention is a measuring probe which has the means to access data flows composed of packets transmitted along a path formed by a plurality of equipment in a communication network, and the measurement means to perform measurements in accordance with configuration data. This probe is characterised in that it possesses, in addition: the determination means which enable it to determine that one or more packets transmitted along this path form a signalling message and the signalling means which enable it to determine the configuration data from this signalling message. Preferentially, these measurements relate to the said data flows. In accordance with one method of implementation of the invention, the measurement means are capable of transmitting measurement reports, containing the measurements, to a measuring device which is determined by an identifier contained in the configuration data. In accordance with one method of implementation of the invention, the measurements are transmitted to the measuring device by means of a proxy (or mediator), where the data transmitted to the proxy contains this identifier. In accordance with one method of implementation of the invention, the means of determination are suitable for reading a specific label contained in the received message, and for determining whether this received message is a signalling message from this specific label. In accordance with one method of implementation of the invention, the configuration base contains a set of records, each record corresponding to a measurement task and containing in particular: a filter determining the packets on which the measurements are to be performed, parameters relating to the method of measurement In particular, the parameters can be chosen from a set consisting of: the time during which the measurements must be performed, sampling data, which is a function of hashing in particular, a parameter triggering the time-stamping of the packets to be measured, a parameter triggering the identification of the packets to be measured, in particular by means of a hashing function. a parameter triggering the counting of the packets, the method for transmitting the measurements to the measuring device. In accordance with one method of implementation of the invention, the transmissions with the measuring device are made secure. In particular, these means of making secure can be transmitted by a signalling message. In accordance with one method of implementation of the invention, the measuring probe consists in addition of the means to decide on the creation of a new measurement task, by the signalling means, in particular in accordance with a sensitivity indicator associated with this measuring probe. In accordance with one method of implementation of the invention, the decision is also a function of a priority contained in the received message. Another objet of the invention is a network element, in particular a router which includes a measuring probe as described previously, as well as a communication network which includes such measuring probes, and possibly a measuring device. Thus, by the use of an “in-path” signalling protocol to indicate to the measuring probes that they must establish measurement tasks, or that they must modify or delete these, the invention allows one not to have prior knowledge of the location of the measuring probes, and to surmount the problem of the measuring probes located in a domain administered by an operator other than that of the measuring device. The invention and its advantages will appear more clearly in the description of its implementation which follows, together with the appended figures. FIG. 1, already mentioned, illustrates a state-of-the-art solution. FIG. 2 represents the functional architecture of a probe according to the invention. FIG. 3 is a schematic representation of communications between the probes according to the invention and a measuring device. FIG. 4 illustrates the probe of the invention in an implementation context. In accordance with various implementations of the invention, the measuring probe can be incorporated into a specific device such as those of the state-of-the-art devices of the Ipanema company, or indeed into network equipment such as a switch, an IP router, etc. In this last case, the measuring probe can, in particular, be a software module capable of being executed by the operating system of the network equipment. This software module can be installed at the time of activation of the network equipment, or indeed later in the context of an update to the software of this equipment, and/or in a dynamic manner by downloading over the network, from a dedicated server for example. This software module can be developed in the Java™ language, for example, in order to facilitate its dynamic implementation on the network equipment. By network equipment is meant a router in particular, in the context of a network based on an IPv4 or IPv6 protocol stack (Internet Protocol, version 4/6). Following this, implementation of the invention for the measurement of quality-of-service parameters will be detailed in particular, although the invention can apply equally well to other parameters. FIG. 2 illustrates the functional architecture of a measuring probe (S), according to the invention. This measuring probe consists firstly of the means of determination (SD). The role of these means of determination is to determiner if one or more packets of incoming data form a signalling message or if they belong to a data flow. In the typical case of a data network based on a protocol stack of the IPv4 type (Internet Protocol version 4) or IPv6 type (Internet Protocol, version 6), the signalling messages can in fact be composed of several data packets. The determination can be accomplished by means of a specific label. This specific label can be a dedicated port number, a dedicated DSCP (DiffServ Code Point), a protocol number of the IP header, etc. If the received group of data packets forms a signalling message, it (or its content) is transmitted to signalling means (SS), the role of which is to interpret the content of this signalling message. According to the content of this message, the signalling means can then modify a configuration base (BC). The configuration base (BC) contains the configuration of the probe. It can consist of a set of records, with each record corresponding to a measurement task. In general, all or part of the records of the configuration base (BC) determines which data flow should be measured by the corresponding measurement task, at which frequency the measurements should be performed, to which parameter they should apply, and so on (We will see later that in accordance with one method of implementation of the invention, certain of these records may not correspond to a measurement task). In accordance with the terminology of the IETF, these records correspond to a state of the probe. These states can be of the same type as those specified for the RSVP protocol (ReSerVation Protocol), for example, specified by RFC 2205 of the IETF. The content of the records will be detailed later, but it is important to note here that the signalling messages can trigger: The establishment of a new measurement task. This establishment process gives rise to the insertion of a new record in the configuration base (BC), and therefore the creation of a new state within the measuring probe. This state can preferentially be of the “soft state” type, meaning that it will be deleted automatically at the end of a certain time period. The refreshing of a state. In the method of implementation in which the states are of the type known as “soft states”, refresh messages are used to prolong this period, by returning a counter to an initial value, for example. Of course, if the states are of the type known as “hard states”, then no refresh message is necessary, since the state will remain installed for as long as a delete message concerning this state is not received. The modification of a measurement task. This type of message can have as its purpose to modify a part of the parameters associated with a previously-established measurement task (for example, to change a sampling rate for the measurements in a dynamic manner, to adapt to the loading on the network, or indeed when close to a critical threshold). The corresponding record in the configuration base (BC) can be modified in order to take account of this modification. The deletion of a measurement task. This deletion can give rise to deletion of the corresponding record in the configuration base (BC). In the situation where the states are of the “hard state” type, deletion messages are transmitted in order to terminate the measurement task and to delete the corresponding state. In addition, in accordance with one method of implementation, the groups of normal packets are transmitted by the means of determination to the measurement means (SM). By normal packets is meant packets whose the content is not interpreted by the routers as are the content of the packets of the various network protocols like the signalling packets, the routing packets, the ICMP packets, etc. However, the invention can also apply to measurement of the flow of “non-normal” packets, such as OSPF (Open Shortest Path First) signalling flow, for example. The role of these measurement means (SM) is to actually perform the measurement on the received packets, according to the configuration stored in the configuration base (BC). More precisely, the role of the measurement means is to process the various tasks which have been put in place in the measuring probe, where the configuration of each task has been specified by the content of the corresponding record in the configuration base (BC). As mentioned previously, this configuration can determine several things for each of the measurement tasks. To begin with, it can determine to what the measurements must apply, meaning the data flows to be measured, by means of a data-flow identifier list, for example. To this end, filters can be put in place, in order, generally speaking, to select a sub-set of packets by the application of determinist functions to parts of the content of the packet, such as header fields or parts of the payload. A filter can also consist of applying a pseudo-probabilistic law to the selection of the sub-set. The concept of a filter can, for example, comply with that specified in the IETF draft entitled “draft-ietf-psam-sample-tech-00.txt”. In particular, these filters can be used to select the packets belonging to one or more of the data flows, on the basis of an identifier list. Typically, in the case of an IP network, these identifiers can be a quintuple composed of the addresses and port numbers of the sender and the receiver of the flow, and of the protocol number. In the case of an IP network V6 (Internet Protocol version 6), the “Flow Label” field can be added to this quintuple. The configuration can also specify how the measurements should be performed. More precisely, it can possibly indicate: the time during which the flow should be the subject of measurements. Alternatively, it is possible not to specify any time, and halting of the measurements must then be indicated by the emission of another signalling message or by the expiry of a timeout in the absence of a refresh message. In accordance with this method of implementation, there exists a soft-state mechanism which is similar to that implemented for the RSVP protocol (ReSerVation Protocol). whether these measurements are to apply to all of the packets or, on the contrary, whether sampling should be employed. In the event of sampling being applied, the configuration can also contain the frequency of the measurements (one packet in n; 1 packet every n milliseconds, etc.), a hashing function with a constraint on the result, and so on. a parameter triggering the time-stamping of the packet, a parameter triggering the identification of the packet using a hashing function. A parameter triggering the counting of the packets, the method for transmitting the measurements to the measuring device (M), in particular if these measurements are to be transmitted for each measurement performed, or indeed if they are to be grouped into a single message in order to limit communications. In this last case, the configuration can contain the frequency of transmission (one transmission for every n measurements, one transmission every n milliseconds, etc.), and so on. etc. As will be seen later, the configuration can also indicate an identifier for the measuring device, and also the means of making secure. The choice of the parameters contained in the signalling message can depend in particular on the type of measurement to be performed. Thus, the parameters can be different if one is measuring an average transmission time or indeed a packet loss rate. In the case of an average transmission-time measurement, one method of implementation of the invention consists of executing the following stages: 1) sampling: it is important not to select all the packets of the sub-set concerned, in order not to encumber the network and collector M, but at the same time a minimum number is necessary. An additional difficulty is that the same packets must be selected by all of the measuring probes in order that a correlation may be possible by the collector(s) (M). A deterministic sampling method is therefore put in place, using a hashing function for example. A hashing function can be a non-bijective mathematical application which is associated with an invariant content of packets (that is one which is not modified by the network elements), such as the payload of the packet, a value which is tested in order to determine if the packet should be part of the sample or not. Since this function is an application, and since it is based on an invariant, two probes will then end up with the same value, and therefore will reach the same decision. In practice, this function can be chosen in accordance with the desired sampling probability, the speed of the data flow, and the entropy of the packet content. 2) Next, a date is associated with the selected packet. At this stage, it is desirable that all of the probes should have their clocks synchronised. To this end, state-of-the-art synchronisation techniques can be used, in particular making use of the GPS (Global Positioning System) or indeed of the NTP (Network Time Protocol), as specified in RFC 1305 of the IETF (Internet Engineering Task Force). 3) In a third stage, the selected packet is “identified”. This means that a value is associated with it which is used to identify it in unique manner from the other packets in the same flow and from those in other data flows. Here again, identification can be achieved by means of a hashing function. The result of the hashing function, which forms the identifier of the packet, should be sufficiently long to prevent two different packets from having identical identifiers. The hashing function should be identical for all of the probes, in order that a given packet is associated with a given identifier and to ensure that the measuring device (M) (or collector) can make the correlation between the reports coming to it from the probes. 4) Finally, the fourth stage consists of transmitting a measurement report to the measuring devices or collector M. Thus, for a given sampled packet, collector M receives several measurement reports from various probes. Using the unicity property of the identifiers, it can easily achieve correlation between its measurement reports, and by comparing the dates inserted in these by the probes, it can determine the timing of the sampled packet between each probe. In this example, the signalling message therefore consists of the following elements: a filter, a hashing function for the sampling, a parameter triggering the time-stamping of the packets, and a hashing function for the identification process. In the case of packet loss rate measurement, the principle is essentially the same as that of the previous example. In accordance with one method of implementation, the difference resides in the fact that, in place of the date of receipt of the packet, the measurement report contains the sequential number of the packet, given by a counter contained in the probe. In this example, the signalling message therefore consists of the following elements: a filter, a hashing function for the sampling, and a parameter triggering the counting of the packets. As mentioned previously, the measurements performed by the measurement means (SM) can then be transmitted to a measuring device, not shown in FIG. 2, the purpose of which can be to consolidate the measurements received from several measuring probes. These measuring devices may also be called “collectors”. An identifier for this measuring devices can, for example, be indicated in configuration base BC. In particular, the nature of this measuring device can vary in accordance with the data flow measurements. This identifier can be supplied by the signalling messages and can be inserted into the configuration base by the signalling means (SS), like all other configuration data. This identifier can be an IP (Internet Protocol) address, or indeed a protocol number or a more abstract address such as a URL (Unified Resource Locator) as described by RFC 2396. In addition, the measurements can be sent to the measuring device by means of proxies or mediators, as shown in FIG. 3. Telecommunication network N is composed of a system of network equipment divided into a number of groups. With each group, G1, G2, G3, . . . Gn, a proxy, respectively P1, P2, P3, . . . Pn, is associated. The measurements taken by the measuring probes of the network equipment are transmitted to the proxy associated with the corresponding group. This proxy can then transmit the measurements to the measuring device (M). In accordance with one method of implementation of the invention, an identifier (the address, for example) of the measuring device (M) is inserted into the measurement reports transmitted to the proxies, so that these are then able to transmit the measurement reports to the appropriate measuring device. Where appropriate, the proxies can perform pre-processing prior to transmission to the measuring device (M). This pre-processing can, for example, simply consist of aggregating the measurements received from the probes, in order to send reports of a more summary nature to the measuring device (M) and to limit the traffic. This method of implementation is advantageous in the case of large telecommunication networks, since it allows a better division of communications between network elements and measuring devices, as well as limiting inter-operator communications in the case of measurements on different networks. In accordance with one method of implementation of the invention, the measurements can be transmitted to the measuring devices in a secure form, encoded by a public key for example. One of the advantages of the invention is that it is easy to establish and determine a large number of measuring probes. These measuring probes can include redundancy, meaning that there can be more of them than necessary. For example, to measure the quality-of-service parameters between 2 points, A and B, two probes would be necessary, but one can choose to establish 2 of them in the vicinity of point A and 2 in the vicinity of point B. The advantage of such redundancy is that it minimises the risks of measurement errors or of a defective measuring probe. Another advantage of the invention that it can easily find and configure measuring probes. The state-of-the-art, 2-probe architectures require one to determine which are the probes which can be used, and to access these. In a multi-domain situation, a measurement can be requested by one operator on a probe of another operator, only with difficulty. In addition to solving these problems, the invention allows several measurements to be performed on the path of a flow, in order to locate a malfunction more easily (congestion, a quality-of-service problem, etc.). Another advantage of the invention is that the measurements are performed by the measuring probes even if they are unaware of the presence of other probes, and consequently of measurements performed by other measuring probes. Also, any intentionally erroneous measurement supplied by a measuring probe can easily be detected by comparison with measurements supplied by nearby measuring probes. In accordance with one method of implementation of the invention, the signalling means (SS) of the measuring probe also have the means to decide whether or not to create a new measurement task. It can be decided to insert into the configuration base (BC) only those records associated with created measurement tasks, or indeed the records associated with any signalling message requiring the creation of a measurement task, whether it is accepted or not by the signalling means (SS). This second implementation is particularly useful when states of the “soft-state” type have been chosen. In this implementation, refresh messages can be received regularly. The fact of keeping a trace of the “refused” signalling messages allows cohesion to be maintained in the decisions made. In order to make these decisions, the measuring probe is associated with a sensitivity indicator. This sensitivity identifier can, for example, represent a probability that the signalling probe will decide to handle the signalling message. For example, when it receives a signalling message, the measuring probe can trigger the drawing of a random number. By comparison with the sensitivity indicator, it easily determines whether the signalling message should be handled or not. In accordance with one implementation, this mechanism applies only to signalling messages containing information relating to the addition of a measurement tasks. On the other hand, signalling messages which modify a measurement task or delete a previously existing measurement task, can still be handled, meaning that it can involve a modification of the configuration base (BC) by the signalling means (SS). In accordance with one implementation of the invention, the signalling messages can contain a priority. The decision to handle the signalling message or not can be weighted by the value of this priority. For example, “routine” measurement jobs (for surveillance, for example) can be assigned a low priority. If an error has been observed at a given moment, a control system will be able to decide to transmit a signalling message with a higher priority in order to trigger measurements by a greater number of measuring probes, thereby allowing more accurate location of the problem. In accordance with one particular method of implementation of the invention, the signalling messages can be stored in another database, not shown in the figure, even if the signalling means decide not to accept the creation of a new measurement task and do not modify the configuration base (BC). FIG. 4 illustrates one implementation of the invention. A communication network consists of 5 measuring probes A, B, C, D and E. A signalling message is transmitted to A and then successively to B, C, D and E. This signalling message contains measurement data relating to the installation of a measurement task. The measuring probes have different sensitivity indicators. Probes A, C, D and E decide to insert these measurement data into their respective configuration bases. Measuring probe B decides to ignore the signalling message and does not modify its configuration base. When messages belonging to the data flow correspond to these measurement data, then probes A, C, D and E take measurements in accordance with these measurement data, as indicated previously. These measurements are transmitted to a measuring device (M). To the extent that measuring probes C and D are juxtaposed, if the measurements transmitted by these two probes differ by more than an acceptable error margin, then the measuring device (M) will be able to determine that at least one of the measuring probes is deficient. If the measurements coming from measuring probes A and C differ by more than a certain level, then the measuring device will be able to determine that there is an anomaly between these two probes. In order to specify the location of the anomaly, measuring device (M) can cause the emission of a new signalling message to measuring probe A, with a higher priority. This time, measuring probe B decides to establish a measurement task, and to insert the measurement data into its configuration base. On receipt of a message from the data flow, measuring probe B will also transmit measurements to the measuring device (M). By comparing the measurements received from probes A and B, and those received from probes B and C, the measuring device can determine whether the anomaly is located between A and B or between B and C (or if it is divided between A and C). A further advantage of the invention is that measuring probes A, C, D and E transmit their measurements independently of each other. Likewise, none of the measuring probes can be informed of the content of the measurements of the other probes, and even of the existence of these measurements or of the measuring probes themselves. This results in a very high level of security and reliability of the invention. In the event that the network is multi-domain in nature, meaning that it is controlled by several operators, these operators can therefore be assured that the measurement data cannot become known to the measuring probes belonging to a domain controlled by another operator. In accordance with one method of implementation of the invention, the signalling messages comply with the following syntax, specified in Backus-Naur form (BNF): <RequestMeasureMessage> = <MeasureID> <acceptance_factor> <FLOW_FILTER> <METERING_ACTIONS> <COLLECTOR> <METERING_ACTIONS>=1*<METERING_ACTION><EXPORTING> <METERING_ACTION>=<COUNTER>/<SAMPLING>/<IDENTIFICATION> <COLLECTOR> = <Collector_address> [<report_frequency>] [<security_data>] This syntax indicates that, for the creation of a measurement task, a signalling message in accordance with the invention includes: an identifier for the measurement task, an “acceptance factor” priority which, in collaboration with the sensitivity indicator, allows you to decide on the creation or not of the measurement task, a “FLOW_FILTER” used to select a sub-set of packets, on which the measurements are to be performed, “METERING_ACTIONS”, which are used to specify which type of processing should be effected by the measurement means (SM), and in particular whether it involves counting, sampling, identification, etc. the identification of a collector (M), in particular its address and optionally its frequency and security parameters. | 20040123 | 20090901 | 20050127 | 62845.0 | 0 | HOM, SHICK C | PROBE FOR MEASURING QUALITY-OF-SERVICE PARAMETERS IN A TELECOMMUNICATION NETWORK | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,762,397 | ACCEPTED | CENTRIFUGAL COMPRESSOR WITH CHANNEL RING DEFINED INLET RECIRCULATION CHANNEL | A centrifugal compressor includes an annular inlet air recirculation channel having a smoothly variable cross section extending from a first slot at a forward end of the channel adjacent an inlet member to a second slot at a rearward end of the channel beyond an inlet end of a vaned compressor impeller. The channel is formed between an aerodynamic channel ring supported in a smooth annular recess formed in a compressor housing and the separate inlet member. The ring may be mounted by radial struts connected with the housing and located in an area of low momentum air flow. The channel ring and the channel recess may be machined or otherwise formed with smoothly variable surfaces prior to assembly of the ring into the housing. The channel may have a smoothly diminishing annular cross section for aerodynamically efficient air flow. | 1. A centrifugal compressor comprising: a centrifugal impeller rotatable on an axis and having impeller vanes extending from an inlet end for fluid entry into the impeller; a compressor housing surrounding the impeller and defining therewith an annular fluid flow passage, the housing having an inlet protruding beyond the impeller inlet and configured for generally axial inlet flow and an outlet configured for generally radial outlet flow; an inlet member attached to the housing inlet and forming an extension configured for generally axial inlet flow into the housing; and a separate channel ring fixed within the housing inlet and forming therewith an annular recirculation channel extending from the inlet member to beyond the impeller inlet end, the channel formed with a smoothly diminishing annular cross section from a first slot at a forward end of the channel adjacent the inlet member to a second slot at a rearward end of the channel beyond the impeller inlet end. 2. A centrifugal compressor as in claim 1 wherein the channel ring is supported in the housing by spaced radial connectors extending across the channel. 3. A centrifugal compressor as in claim 2 wherein the connectors are radial struts carried by the channel ring and extending into slots of the housing inlet. 4. A centrifugal compressor as in claim 2 wherein the connectors are positioned axially near a forward end of the channel ring. 5. A centrifugal compressor as in claim 1 wherein the channel ring has an aerodynamic cross section. 6. A centrifugal compressor as in claim 1 wherein the forward end of the impeller is positioned closer to the second slot than to the first slot. 7. A centrifugal compressor comprising: a centrifugal impeller rotatable on an axis and having impeller vanes extending from an inlet end for fluid entry into the impeller; a compressor housing surrounding the impeller and defining therewith an annular fluid flow passage, the housing having an inlet protruding beyond the impeller inlet and configured for generally axial inlet flow; an inlet member attached to the housing inlet and forming an extension configured for generally axial inlet flow into the housing; and a separate channel ring fixed within the housing inlet and forming therewith an annular recirculation channel extending from the inlet member to beyond the impeller inlet end, the channel formed with a smoothly varying annular cross section from a first slot at a forward end of the channel adjacent the inlet member to a second slot at a rearward end of the channel beyond the impeller inlet end. 8. A centrifugal compressor as in claim 7 wherein the channel ring has an aerodynamic cross section. 9. A centrifugal compressor as in claim 7 wherein the channel ring is supported in the housing by spaced radial connectors extending across the channel. | TECHNICAL FIELD This invention relates to centrifugal compressors and to a channel ring defined inlet recirculation channel for such compressors. BACKGROUND OF THE INVENTION It is known in the art relating to centrifugal compressors for air and other compressible gases that the operational range of pressure ratios of the compressor may be increased by providing bleed passages in the housing at suitable locations adjacent the impeller. This is particularly useful for engine turbocharger compressors, which are intended to operate over a wide range of rotational speeds under various conditions of engine speed, load and ambient pressure. In particular cases, air inlet recirculation has been proposed; however, the recirculation passages and the inlet and outlet slots have varied in cross-sectional area and smoothness and have not been designed for flow efficiency. SUMMARY OF THE INVENTION The present invention provides an integrated turbocharger inlet design that allows optimizing aerodynamic performance of a centrifugal compressor utilizing inlet air recirculation. Configuring the inlet components in an aerodynamic fixed configuration minimizes losses associated with prior designs of fixed geometry and costs associated with more complicated designs of variable geometry. The invention provides efficient compressor inlet air recirculation with a simple fixed channel system. In a preferred embodiment, three components, a compressor housing, an inlet member and a channel ring are interrelated to optimize the location, size and shape of a channel that joins a circumferential slot adjacent to the impeller with a circumferential opening preceding the impeller. Use of the separate channel ring allows all surfaces of the channel to be accurately configured, by machining if required, to obtain an efficient flow channel configuration. Radial supports connecting the ring to the housing and inlet member are located near the channel inlet in an area of relatively low momentum air flow to prevent aerodynamic disturbances from adversely affecting the impeller during rotation at high speeds. These and other features and advantages of the invention will be more fully understood from the following description of certain specific embodiments of the invention taken together with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of the compressor end of an engine turbocharger having a recirculation channel in accordance with the invention; and FIG. 2 is an enlarged cross-sectional view of the recirculation channel portion of the embodiment of FIG. 1. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings in detail, numeral 10 generally indicates a centrifugal compressor forming a portion of an engine turbocharger 11. The turbocharger includes an exhaust driven turbine, not shown, connected with a drive shaft 12 for rotatably driving an impeller 14 of the compressor. However, the features of the invention could also apply to other centrifugal compressors whether or not connected with engines or turbochargers. The turbine, drive shaft and impeller are fixed together for rotation on a longitudinal axis 16. The impeller 14 includes a plurality of vanes 18, each having a leading edge 20, a trailing edge 22 and an outer edge 24. The compressor 10 further includes a compressor housing 26, a diffuser 28, an outlet scroll 30, an inlet member 32 and a channel ring 34. The compressor housing includes an annular wall 35 having an inlet portion 36, an intermediate portion 38, and an outlet portion 40 that forms a front wall for the diffuser. The outlet scroll 30 mounts around the diffuser 28 and the outlet portion 40 of the annular wall 35 to receive pressurized gas, such as air, from the diffuser 28. The intermediate portion 38 extends for most of the length of and closely proximate to the outer edges 24 of the vanes 18. The inlet member 32 is fixed to the inlet portion 36 of the housing wall and forms an inlet passage 42 of cylindrical or slightly frusto-conical configuration. The channel ring 34 has radial lugs or struts 44 that are fixed in slots 46 of the housing wall inlet portion 36. Alternatively, other forms of attachment, such as pins, could be utilized. Surrounding the channel ring 34, the inner end of the inlet member 32 and the adjoining inlet end of the inlet portion 36 form an outwardly curved annular recess 48 in which an annular body 50 of the channel ring 34 is received. The body 50 of the channel ring 34 has an aerodynamic configuration which, in cross section of the illustrated embodiment, resembles an airfoil. An outer surface 52 of the ring 34 is curved in a manner similar to an upper surface of an aircraft wing having, for example, a rounded leading edge 54 connected with the outer surface 52 curving inward to a relatively sharp trailing edge 56 of the ring 34. A connecting inner surface 58 extends linearly in a straight or slightly curved fashion from the inside of the rounded leading edge 54 to the sharp trailing edge 56. The ring inner surface 58 extends longitudinally in relatively close alignment with the inlet passage 42 of the inlet member 32 and the interior of the intermediate portion 38 of the housing wall. The outer surface 52 of the channel ring is spaced inwardly from an opposing inner surface of the outwardly curved annular recess 48 to define an annular recirculation channel 60. The channel 60 is configured with a smoothly diminishing annular cross section from a first slot 62, at a forward end of the channel adjacent the inlet member, to a second slot 64 at a rearward end of the channel slightly beyond the inlet end of the impeller as defined by the leading edges 20 of the impeller vanes 18. The thickness and longitudinal extent of the recirculation channel may be varied to obtain the desired amount and direction of recirculation air flow during operation of the compressor from the stall condition to the surge line of the pressure ratio map. The smaller cross section of the channel at the rearward second slot 64 allows flow into the impeller periphery to merge smoothly with the through flowing air stream. The larger cross section at the forward first slot 62 moderates air flow at this location to minimize the effect of reverse flow turbulence on the impeller blades leading edges. The radial support struts 44 are located in a zone of low momentum air flow near the opening of the first slot to minimize their effect upon the air flow in either forward or reverse directions. In operation of the compressor with low mass air flow, air enters the inlet member 32 and is directed into the impeller 14, passing the leading edges 20 of at least some of the vanes 18. Then inlet pressure differentials cause some of the air flow along the inner surface 58 of the channel ring to enter the second slot 64 and recirculate through the channel 60 and first slot 62 into the main inlet air stream upstream of the impeller. As the impeller speed increases, the recirculation flow decreases until the pressure differentials are reversed at higher mass flows. Then, some of the inlet air flow enters the first slot 62, passes through the channel 60 to the second slot 64 and reenters the main air stream, passing through the impeller vanes 18 and supplementing the air flow through the impeller. The compressor air inlet system described provides both the functions of recirculating inlet air at low mass flows to move the surge line and increase operating range and bypassing inlet air at higher mass flows to increase the air flow passing through the impeller and being discharged from the compressor. Use of the separate channel ring 34 allows the surfaces defining the recirculation channel 60, as well as the inner surface 58 of the channel ring, to be fully machined or otherwise formed, prior to assembly, with smooth low friction surfaces and with close tolerances to minimize aerodynamic losses of the air flow in the channel. Mounting of the inlet member 32 and the channel ring radial struts, both, directly to the compressor housing also minimizes tolerance stack up, and positioning of the struts minimizes flow disturbances at the channel outlet slots. A minimum number of struts, such as four, is preferred for minimal flow interference. These features all contribute to the efficiency of the low loss channel design, the configuration of which may be varied as needed to match various compressor configurations. In summary, the invention emphasizes the following features: a compact, fixed geometry; a simple, cost-effective construction including profiled recirculation channel surfaces and slot openings; slots easily modified for differing impeller geometries; inner channel geometry minimizing fluid momentum loss to increase compressor efficiency; and minimal channel obstructions away from the rear impeller slot 64 to prevent aero-mechanical excitation of the impeller at higher air flows. While the invention has been described by reference to certain preferred embodiments, it should be understood that numerous changes could be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the disclosed embodiments, but that it have the full scope permitted by the language of the following claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>It is known in the art relating to centrifugal compressors for air and other compressible gases that the operational range of pressure ratios of the compressor may be increased by providing bleed passages in the housing at suitable locations adjacent the impeller. This is particularly useful for engine turbocharger compressors, which are intended to operate over a wide range of rotational speeds under various conditions of engine speed, load and ambient pressure. In particular cases, air inlet recirculation has been proposed; however, the recirculation passages and the inlet and outlet slots have varied in cross-sectional area and smoothness and have not been designed for flow efficiency. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention provides an integrated turbocharger inlet design that allows optimizing aerodynamic performance of a centrifugal compressor utilizing inlet air recirculation. Configuring the inlet components in an aerodynamic fixed configuration minimizes losses associated with prior designs of fixed geometry and costs associated with more complicated designs of variable geometry. The invention provides efficient compressor inlet air recirculation with a simple fixed channel system. In a preferred embodiment, three components, a compressor housing, an inlet member and a channel ring are interrelated to optimize the location, size and shape of a channel that joins a circumferential slot adjacent to the impeller with a circumferential opening preceding the impeller. Use of the separate channel ring allows all surfaces of the channel to be accurately configured, by machining if required, to obtain an efficient flow channel configuration. Radial supports connecting the ring to the housing and inlet member are located near the channel inlet in an area of relatively low momentum air flow to prevent aerodynamic disturbances from adversely affecting the impeller during rotation at high speeds. These and other features and advantages of the invention will be more fully understood from the following description of certain specific embodiments of the invention taken together with the accompanying drawings. | 20040122 | 20050920 | 20050728 | 95937.0 | 2 | NGUYEN, NINH H | CENTRIFUGAL COMPRESSOR WITH CHANNEL RING DEFINED INLET RECIRCULATION CHANNEL | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,762,451 | ACCEPTED | Semiconductor device and fabrication method thereof | An efficient fabrication method of a SON type semiconductor device is to be provided. A plurality of linear leadframes is arranged side by side separately from each other. A plurality of semiconductor chips with a plurality of electrode pads is mounted over the plurality of the linear leadframes separately in the direction of extending the linear leadframes. The plurality of the electrode pads is joined to the plurality of the linear leadframes with bonding wires. An encapsulation part for encapsulating the semiconductor chip and the bonding wires and an interframe encapsulation part for burying a space between the linear leadframes exposed outside the encapsulation part are formed. A groove part for cutting all the linear leadframes placed right under the semiconductor chip in the vertical direction to the direction of extending the linear leadframes is formed. The leadframes and the interframe encapsulation parts exposed between the plurality of the semiconductor chips are cut to separate into a semiconductor device. | 1. A fabrication method of a semiconductor device comprising: arranging a plurality of linear leadframes side by side separately from each other; mounting a plurality of semiconductor chips having a first main surface with a plurality of electrode pads and a second main surface facing the first main surface, each of the semiconductor chips placed over the plurality of the linear leadframes and separated from each other in a direction of extending the linear leadframes with the second main surface of each of the semiconductor chips thereon; joining the plurality of the electrode pads to the plurality of the linear leadframes with bonding wires; forming the an encapsulation part for encapsulating the semiconductor chip and the bonding wire and an interframe encapsulation part for burying a space between the adjacent linear leadframes exposed outside the encapsulation part; forming a groove part for cutting all the linear leadframes placed right under the second main surface in a vertical direction to the direction of extending the linear leadframes; and cutting the leadframes and the interframe encapsulation parts exposed between the plurality of the semiconductor chips to separate into a semiconductor device having the semiconductor chip, a first external terminal row and a second external terminal row facing each other as sandwich the groove part. 2. The fabrication method of the semiconductor device according to claim 1, wherein the mounting is conducted by exposing outermost leadframes on both sides among the plurality of the linear leadframes arranged side by side, and the joining does not join the bonding wires to the outermost leadframes. 3. A fabrication method of a semiconductor device comprising: arranging a plurality of linear leadframes side by side separately from each other; mounting a plurality of semiconductor chips having a first main surface with a plurality of electrode pads and a second main surface facing the first main surface, each of the semiconductor chips placed over the plurality of the linear leadframes and separated from each other in a direction of extending the linear leadframes with the second main surface of each of the semiconductor chips thereon; joining the plurality of the electrode pads to the plurality of the linear leadframes with bonding wires; forming an encapsulation layer for encapsulating the plurality of the semiconductor chips and the bonding wires joined to each of the plurality of the semiconductor chips; forming a groove part for cutting all the linear leadframes placed right under the second main surface in a vertical direction to the direction of extending the linear leadframes; and cutting the encapsulation layer and the leadframes between the plurality of the semiconductor chips to separate into a semiconductor device formed of the semiconductor chip and the remaining leadframes having a first external terminal row and a the second external terminal row facing each other as sandwich the groove part, the rows exposed from a section generated by cutting. 4. The fabrication method of the semiconductor device according to claim 3, wherein the mounting is conducted by exposing outermost leadframes on both sides among the plurality of the linear leadframes arranged side by side, and the joining does not join the bonding wires to the outermost leadframes. 5. A semiconductor device comprising: a plurality of first external terminals disposed separately from each other; a plurality of second external terminals separate from the first external terminals on an extension of the first external terminals; a semiconductor chip having a plurality of electrode pads and mounted on the first and second external terminals; a plurality of bonding wires for joining the plurality of the electrode pads to each of the first and second external terminals; an encapsulation part for encapsulating the semiconductor chip and the bonding wires; and a frame encapsulation part for encapsulating between the first external terminals and between the second external terminals. 6. The semiconductor device according to claim 5, wherein the encapsulation part and the frame encapsulation part are formed in one piece. 7. The semiconductor device according to claim 5, wherein the plurality of the first external terminals are separated in stripes. | BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a fabrication method thereof, particularly to a SON (Small Outline Non-Lead Package) type semiconductor device and a fabrication method thereof. 2. Description of the Related Art A semiconductor device is known in which an external electrode of a semiconductor chip is electrically connected to a conductor terminal with a bonding wire and the semiconductor chip, the bonding wire and the conductor terminal are encapsulated with an insulator. In the semiconductor device like this, a so-called SON type semiconductor device is known in which a conductor terminal is exposed from an insulator. Furthermore, in order to reduce the exposure failure of the conductor terminal of the SON type semiconductor device like this, a fabrication process of a conductor terminal is known in which the conductor terminal is formed with the use of a conductor that an adhesion to a substrate is reduced under a predetermined condition and the adhesion between the substrate and the conductor terminal is reduced for removal under a predetermined condition after its encapsulation process step (for example, see Patent Document 1). Patent Document 1 JP-A-2003-078076 SUMMARY OF THE INVENTION In the fabrication process of the traditional SON type semiconductor device like this, a leadframe needs to be prepared with matching to the size of a semiconductor chip or the arrangement of electrode pads formed on the top surface of the semiconductor chip, that is, for every semiconductor chip of particular specifications. In addition, according to the traditional fabrication process, a dice bonding process step, a wire bonding process step, a resin encapsulation process step, and a separation process step cannot be combined into a series of process steps. Therefore, since semiconductor devices in midstream of fabrication dwell until they are processed by the subsequent process step, the time required to fabricate a semiconductor device is increased. The invention has been made in view of the problems. In order to solve the problems, a fabrication method of a semiconductor device according to the invention mainly includes the process steps below. More specifically, first, a plurality of linear leadframes is arranged side by side separately from each other. Then, a plurality of semiconductor chips having a first main surface with a plurality of electrode pads and a second main surface facing the first main surface is placed over a plurality of linear leadframes and separated from each other in the direction of extending the linear leadframes with the second main surface of each of the semiconductor chips mounted thereon. Furthermore, the plurality of the electrode pads is joined to the plurality of the linear leadframes with bonding wires. Moreover, an encapsulation part for encapsulating the semiconductor chip and the bonding wires and an interframe encapsulation part for burying a space between the adjacent linear leadframes exposed outside the encapsulation part are formed. Subsequently, a groove part for cutting all the linear leadframes placed right under the second main surface in the vertical direction to the direction of extending the linear leadframes. After that, the leadframes and the interframe encapsulation parts exposed between the plurality of the semiconductor chips are cut to separate into semiconductor devices having the semiconductor chip and a first external terminal row and a second external terminal row facing each other as sandwich the groove part. According to the fabrication method of the semiconductor device according to the invention, since the interval between the leadframes arranged is easily matched to the interval between the external terminals, leadframes do not need to be prepared for every semiconductor chip with particular specifications. Moreover, the dice bonding process step, the wire bonding process step, the resin encapsulation process step, and the separation process step can be conducted in a series of process steps on the plurality of the leadframes arranged. Therefore, the semiconductor devices in midstream of fabrication do not dwell until they are processed by the subsequent process step. Accordingly, many semiconductor devices can be fabricated efficiently for a short time. Furthermore, it also contributes to the reduction in the fabrication costs of the semiconductor device. BRIEF DESCRIPTION OF THE DRAWINGS The teachings of the invention can be readily understood by considering the following detailed description in conjunction with the accompanying drawings, in which: FIG. 1 is a schematic diagram for illustrating the outline of a fabrication apparatus for conducting the fabrication method of the semiconductor device according to the invention, and the outline of each of the process steps included in the fabrication method according to the invention; FIGS. 2A to 2D are fabrication process diagrams (No. 1) depicting a semiconductor device of a first embodiment; FIGS. 3A to 3D are fabrication process diagrams (No. 2) depicting the semiconductor device of the first embodiment; FIGS. 4A to 4C are fabrication process diagrams (No. 3) depicting the semiconductor device of the first embodiment; FIGS. 5A to 5C are schematic diagrams depicting the semiconductor device of the first embodiment; FIGS. 6A to 6D are fabrication process diagrams depicting a semiconductor device of a second embodiment; and FIGS. 7A to 7C are schematic diagrams depicting the semiconductor device of the second embodiment. DESCRIPTION OF THE PREFERRED EMBODIMENT Hereinafter, embodiments according to the invention will be described with reference to the drawings. In addition, the shape, size and arrangement of each component are only shown schematically in the drawings to the extent that the invention is understood, which do not define the invention particularly. Besides, specific materials, conditions and numeric conditions are sometimes used in the description below, but they are merely one of preferable examples. Thus, the invention is not defined by them at all. Moreover, the fabrication process of the semiconductor device according to the invention can be formed by traditionally well-known fabrication process steps with the use of traditionally well-known materials. Therefore, the detailed description of the traditionally well-known fabrication process steps might be omitted. First, an overview of the fabrication method of the semiconductor device according to the invention will be described. FIG. 1 is a schematic diagram for illustrating the outline of a fabrication apparatus 100 for conducting the fabrication method of the semiconductor device according to the invention, and the outline of each of the process steps included in the fabrication method according to the invention. A semiconductor device according to the invention is fabricated by the fabrication apparatus 100 having first and second reels 110a and 110b separated in parallel to each other. More specifically, the fabrication method of the semiconductor device according to the invention is characterized in that all of a dice-bonding process step 120, a wire bonding process step 122, an encapsulation process step 124, an external terminal forming process step 126, and a separation process step 128 are conducted on leadframes 12, which will be described below in detail. Both end parts of the leadframe 12 are extended between first and second reels 110a and 110b, respectively. Furthermore, the both end parts of the leadframe 12 are wound on the two first and second reels 110a and 110b in the reverse directions each other. A plurality of the leadframes 12 is separated from each other in stripes and extended and held between the two first and second reels 110a and 110b. In order to prevent the misalignment of the plurality of the leadframes 12, a plurality of grooves (not shown) is preferably formed with matching to the interval between the leadframes 12, and the leadframes 12 are wounded in the corresponding grooves. The dice bonding process step 120, the wire bonding process step 122, the encapsulation process step 124, the external terminal forming process step 126, and the separation process step 128 can be conducted at the same time by rotating the two first and second reels 110a and 110b in the same directions at the same time and moving them sequentially. First, the dice bonding process step 120 of mounting first semiconductor chips on the leadframes 12 is conducted. Then, the first and second reels 110a and 110b are rotated in the same directions to move a first semiconductor chip by a predetermined distance. The dice bonding process step of mounting a second semiconductor chip on the area generated by the movement is conducted. At this time of the dice bonding process step, the first semiconductor chip moved undergoes the wire bonding process step 122. In this manner, after completion of each process step, the leadframes 12 are sequentially moved in the direction from the first reel 110a to the second reel 110b, the dice bonding process step 120, the wire bonding process step 122, the encapsulation process step 124, the external terminal forming process step 126, and the separation process step 128 are conducted at the same time. The leadframes 12 are placed on a platen or table-shaped structure provided for the fabrication apparatus used in each of the process steps for conducting each of the process steps. Furthermore, for example, it is acceptable to conduct each of the process steps as the leadframes 12 are placed on a structure such as a platen that moves as it follows the rotations of the first and second reels 110a and 110b, that is, the movement of the leadframes 12. Moreover, each of the process steps can be freely conducted to a preferable number of the semiconductor chip, one, two or more. In the example described below, an example that each of the process steps is conducted as two semiconductor chips are one unit will be described. First Embodiment 1-1. Fabrication Method of the Semiconductor Device The fabrication method of the semiconductor device of the first embodiment according to the invention will be described with reference to FIGS. 2A to 4D. FIGS. 2A to 2D are explanatory diagrams (No. 1) for illustrating the fabrication process steps of the semiconductor device of the first embodiment. FIG. 2A is a schematic plan view for illustrating the fabrication process step of the semiconductor device. FIG. 2B is a schematic diagram depicting a section cut by an alternate long and short dashed line indicated by 2B-2B shown in FIG. 2A. FIG. 2C is a schematic plan view for illustrating the fabrication process step of the semiconductor device. FIG. 2D is a schematic diagram depicting a section cut by an alternate long and short dashed line indicated by 2D-2D shown in FIG. 2C. FIGS. 3A to 3D are explanatory diagrams (No. 2) depicting the fabrication process steps of the semiconductor device of the first embodiment. FIG. 3A is a schematic plan view for illustrating the fabrication process step of the semiconductor device. FIG. 3B is a schematic diagram depicting a section cut by an alternate long and short dashed line indicated by 3B-3B shown in FIG. 3A. FIG. 3C is a schematic plan view for illustrating fabrication process step of the semiconductor device. FIG. 3D is a schematic diagram depicting a section cut by an alternate long and short dashed line indicated by 3D-3D shown in FIG. 3C. FIGS. 4A to 4C are explanatory diagrams (No. 3) depicting the fabrication process steps of the semiconductor device of the first embodiment. FIG. 4A is a schematic plan view for illustrating the fabrication process step of the semiconductor device. FIG. 4B is a schematic diagram depicting a section cut by an alternate long and short dashed line indicated by 4B-4B shown in FIG. 4A. FIG. 4C is a schematic plan view for illustrating the fabrication process step of the semiconductor device. The leadframe 12 used for the fabrication method according to the invention has a long, linear shape. These leadframes 12 are preferably formed in bands (strips) of a conductive metal material such as cupper or a cupper alloy. The shorter length (width) is about 0.2 to 0.5 mm, in a typical standard example in the present semiconductor device. As shown in FIG. 2A, a plurality of the leadframes 12 is separated in stripes at an equal interval d, and is extended and held between the two first and second reels 110a and 110b as described above. The leadframe 12 functions as the external terminal of the semiconductor device to be fabricated. Therefore, the interval d between the plurality of the leadframes 12 disposed in parallel to each other is determined to be equal to the interval between the external terminals in accordance with the specifications of the semiconductor chip to be mounted on the leadframes 12 and the specifications of the semiconductor device to be fabricated, which will be described later. The interval between the external terminals corresponding to the interval d between the leadframes 12 is about 0.5 to 1.5 mm, in a typical standard example in the present semiconductor device. Therefore, in this example, the example that the plurality of the leadframes 12 is arranged at the equal interval d will be described, but it is easy to arrange the leadframes 12 at different intervals in accordance with the specifications of external terminals, for example. As shown in FIG. 2A, among the plurality of the leadframes 12 arranged side by side, two leadframes 12 placed at the outermost positions are referred to as a first outermost leadframe 12a and a second outermost leadframe 12b, respectively. As shown in FIG. 2B, one main surface of the leadframe 12 is a front side 12c, and the other main surface is a back side 12d. The front side 12c is also called a top surface, and the backside 12d is also called an under surface. Preferably, palladium is coated over throughout the surface including the top surface 12c and the under surface 12d beforehand by a plating process step according to traditional methods. Subsequently, as shown in FIG. 2C, semiconductor chips 20 are arranged separately from each other in the direction (long direction) of extending the leadframes 12 so that each of the semiconductor chips 20 is placed over the plurality of the linear leadframes 12. The semiconductor chip 20 generally has a substantially rectangular parallelepiped. The semiconductor chip 20 has a first main surface 20a with a plurality of electrode pads 22 and a second main surface 20b facing to the first main surface 20a. The first main surface 20a and the second main surface 20b of the semiconductor chip 20 are the same rectangular shape in this example. Furthermore, two end faces 20c and 20c facing each other and two side faces 20d and 20d orthogonal to the end faces 20c and 20c and facing each other are between the first and second main surfaces. Here, suppose the number of the leadframes 12 is seven and the number of the semiconductor chips 20 to be mounted is two for description. The semiconductor chip 20 is dice-bonded on the leadframes 12 so that the long direction of the rectangular of the first main surface 20a and the second main surface 20b is orthogonal to the direction of extending the leadframes 12. In this case, the end faces 20c and 20c 6f the semiconductor chip 20 are along the direction of extending the leadframes 12, and the semiconductor chip 20 is not mounted on the leadframes 12 adjacent to the first and second outermost leadframes 12a and 12b. More specifically, two each of the leadframes 12 including the first and second outermost leadframes 12a and 12b on the outside are exposed from the mounted semiconductor chip 20. In mounting the semiconductor chip, the second main surface 20b of the semiconductor chip 20 is attached onto the top surfaces 12c of three leadframes 12 in the center through an insulating adhesive 30 (FIG. 2D). As the insulating adhesive 30, traditionally well-known products can be preferably used freely. For the adhesive 30, insulating adhesive tapes, for example, are acceptable as well as paste adhesives. The electrode pads 22 are disposed and exposed on the first main surface 20a. In this example, five each of the plurality of the electrode pads 22 are arranged along two side faces 20d and 20d of the semiconductor chip 20 so that the electrode pads 22 along the same side faces are arranged at equal intervals. Moreover, the electrode pads on each of the side faces 20d and 20d are arranged and faced to each other at equal intervals. As described above, the interval d between the plurality of the leadframes 12 is determined equal to the interval between the external terminals of the semiconductor chips to be mounted on the leadframes 12 or the semiconductor device to be fabricated. The interval between the external terminals is determined in accordance with the specifications of the semiconductor chip 20 or the semiconductor device 10 to be fabricated. Then, the electrode pads 22 are joined to five leadframes 12 inside with bonding wires 40 (FIGS. 3A and 3B). The bonding process step is freely conducted by preferable methods such as thermo compression bonding and ultrasonic thermo compression bonding with the use of traditionally well-known bonding wires and a bonding apparatus. At this time, the configuration is fine that the bonding wires 40 are not joined to the first and second outermost leadframes 12a and 12b. With doing this, it is easy to prevent an encapsulation resin material from leaking over the first and second outermost leadframes 12a and 12b in the encapsulation process step, which will be described later. The bonding wires 40 are bonded to the leadframes 12 exposed around the semiconductor chip 20. In the exemplary configuration shown in the drawing, a pair of electrode pads 22 on a straight line along the direction of extending a leadframe 12 is joined to the same leadframe 12 among the electrode pads 22 of the semiconductor chip 20. Subsequently, as shown in FIGS. 3C and 3D, an encapsulation part 50 for encapsulating the semiconductor chip 20 and the bonding wires 40 is formed. The appearance of the structure where the encapsulation part 50 is formed is a substantially rectangular parallelepiped. The side faces around the rectangular parallelepiped are encapsulation part side faces 50b and 50b and encapsulation part end faces 50c and 50c. The encapsulation part 50 can be formed by a traditionally well-known encapsulation process step with a mold, for example, with the use of proper materials such as traditionally well-known molding resins and liquid resins freely. In this example, the encapsulation process step can be conducted by using a traditionally well-known encapsulation apparatus with a mold capable of forming a cavity that can house a single semiconductor chip bonded on the leadframes 12, for example. More specifically, a cavity to house a single semiconductor chip is formed by an upper mold to surround a single semiconductor chip 20 as contacted with the top surfaces 12c of the leadframes 12 on which the semiconductor chip 20 is mounted and a lower mold contacted with throughout the under surfaces 12d (both molds are not shown). Then, the encapsulation resin material is filled in the cavity and cured to form the encapsulation part 50. Therefore, the encapsulation part 50 of the semiconductor device 10 of the embodiment is formed so as to package the semiconductor chip 20 one each. By the encapsulation process step, the spaces between the plurality of the linear leadframes are also buried with the encapsulation resin material to form interframe encapsulation parts 50d. However, at this time, the top surfaces 12c of the leadframes 12 outside the encapsulation part 50 are exposed. After that, all the leadframes 12 placed right under the second main surface 20b of the semiconductor chip 20 are cut in the vertical direction to the end faces 20c and 20c of the semiconductor device 20, that is, the direction along the side faces 20d and 20d. A groove part 60 is thus formed. This process step can be conducted by using a traditionally well-known dicing apparatus. As shown in FIG. 4A, in this example, a dicing line A is set beforehand on the second main surface 20b (see FIG. 4B) along the direction orthogonal to the direction of extending the leadframes 12. The dicing line A is a line passing through the center of the width of the second main-surface 20b along the direction of extending the leadframes 12. The dicing line A preferably divides the areas of the first and second main surfaces 20a and 20b and the end faces 20c and 20c into two equally. As shown in FIG. 4B, the groove part 60 is formed along the dicing line A across at least the leadframes 12 on which the second main surface 20b of the semiconductor chip 20 is mounted for cutting them. At this time, the depth (height) of the groove part 60 is determined as the depth that the leadframes 12 can be cut completely and the range that the function of the semiconductor chip 20 is not impaired. Therefore, it is fine that the depth is set to expose the second main surface 20b of the semiconductor chip 20 at the maximum. In the process step of cutting the leadframes 12, that is, the process step of forming the groove part 60, it is preferable to form the groove part 60 so as not to cut the first and second outermost leadframes 12a and 12b. With doing this, since the encapsulation resin material is filled between the adjacent leadframes and continues to the outermost leadframes 12a and 12b, the strength of the entire structure of connecting the semiconductor devices in midstream of fabrication can be secured. Therefore, a plurality of the connected semiconductor devices in midstream of fabrication can be moved easily and sequentially after the completion of the process steps by the first and second outermost leadframes 12a and 12b that are not cut for implementing it in a series of the fabrication process steps, as conducted in the fabrication process of TCP, for example. After that, as shown in FIG. 4C, each of the semiconductor chips 20 is cut therearound to separate into the semiconductor device 10 including the semiconductor chip 20 (see, FIG. 5A). Also in the separation process step, the first and second outermost leadframes 12a and 12b are not cut. The separation process step is conducted by pressing molds surrounding the area enclosed by a broken line B shown in FIG. 4C, such as upper and lower molds with the same shapes as those used in the encapsulation process step. Pressing the molds can cut a plurality of the leadframes 12 inside and the interframe encapsulation parts 50d burying the spaces between the leadframes 12. The separation process step like this is conducted to obtain the semiconductor device 10. In this manner, according to the fabrication method of the semiconductor device of the invention, since a plurality of the process steps can be conducted on the leadframes 12 continuously, the semiconductor devices in midstream of fabrication do not dwell until they are processed by the subsequent process step before. Accordingly, many semiconductor devices can be fabricated efficiently for a short time. Furthermore, it contributes to the reduction in the fabrication costs of the semiconductor device. 1-2. Semiconductor Device The configuration of the semiconductor device fabricated by the fabrication method of the first embodiment described with reference to FIGS. 2A to 4C will be described with reference to FIGS. 5A, 5B and 5C. FIG. 5A is a schematic perspective view for illustrating the exemplary configuration of the semiconductor device 10 of the first embodiment. FIG. 5B is a schematic diagram depicting a section of the semiconductor device 10 cut by an alternate long and short dashed line indicated by 5B-5B shown in FIG. 5A. FIG. 5C is a plan view depicting the semiconductor device 10 seen from the bottom (external terminal side). In addition, in the description of the semiconductor device, selection of materials for each component is described already, thus omitting the detailed description. The semiconductor device 10 fabricated by the fabrication method of the semiconductor device of the first embodiment includes the semiconductor chip 20. As described above, the semiconductor chip 20 is in a nearly rectangular parallelepiped having the first main surface 20a, the second main surface 20b facing the first main surface 20a, and the end faces 20c and the side faces 20d between the first main surface 20a and the second main surface 20b. The plurality of the electrode pads 22 is exposed from the first main surface 20a. The plurality of the electrode pads 22 is arranged along the side faces 20d on the first main surface 20a (see FIG. 2C). The semiconductor device 10 includes a plurality of external terminals 14. The external terminals 14 are disposed and attached on the second main surface 20b of the semiconductor chip 20 through the insulating adhesive 30. In this example, the external terminal 14 is formed of the leadframe 12 in a strip. As described above, the interframe encapsulation part 50d is disposed between the side faces of the leadframes 12. As shown in FIG. 5B, the external terminals 14 are disposed so as to be exposed from the outline of the semiconductor chip 20. More specifically, the external terminals 14 are disposed as a first external terminal row 14X including a plurality of first external terminals 14a. Similarly, a second external terminal row 14Y including a plurality of second external terminals 14b is also disposed on the other side face 20d. In this example, the first external terminal row 14X and the second external terminal row 14Y face each other as sandwich the groove part 60 extending in the vertical direction to the end faces 20c and 20c. The first and second external terminals 14a and 14b are extended in the vertical direction to the side faces 20d facing each other, respectively, and arranged side by side at a predetermined distance apart in the plane in parallel to the second main surface 20b of the semiconductor chip 20, that is, at equal intervals in this example. The electrode pads 22 and the external terminals 14 are joined to each other with the bonding wires 40. In this example, the surfaces of the electrode pad 22 and the external terminal 14, that is, front sides 14aa and 14ba are joined in correspondence one for one. The semiconductor device 10 has the encapsulation part 50 for encapsulating the semiconductor chip 20 and the bonding wires 40 and the interframe encapsulation parts 50d outside the encapsulation part 50. In this example, the encapsulation part 50 is disposed as a shape where a structure of a nearly rectangular parallelepiped is placed on the first and second external terminal rows 14X and 14Y. The interframe encapsulation parts 50d are disposed so as to bury the spaces between a plurality of the external terminals 14a and between the external terminals 14b as exposed outside the encapsulation part 50. However, the interframe encapsulation parts 50d are disposed so as to expose a part of the front sides 14aa and 14ba and back sides 14ab and 14bb of the external terminals 14a and 14b. According to the semiconductor device of the first embodiment, since the external terminals 14 are disposed two-dimensionally as adjoin the second main surface 20b of the semiconductor chip 20, the semiconductor device can be formed in a lower profile, that is, in a smaller shape. Moreover, since the external terminals are exposed widely on the back side, heat generated by the semiconductor chip can be dissipated efficiently. Second Embodiment 2-1. Fabrication Method of the Semiconductor Device A fabrication method of a semiconductor device of a second embodiment according to the invention will be described with reference to FIGS. 6A to 6D. In addition, the differences between the fabrication method of the semiconductor device of the embodiment and the semiconductor device fabricated by the fabrication method and the first embodiment reside in the process step of forming an encapsulation part 50, the shape of the encapsulation part 50, and a separation process step. Thus, they will be described, and the drawings and detailed description of the same process steps and configurations as those in the first embodiment are omitted. FIGS. 6A to 6D are explanatory diagrams depicting the fabrication process steps of the semiconductor device of the second embodiment. FIG. 6A is a schematic plan view for illustrating the fabrication process step of the semiconductor device, particularly the encapsulation process step. FIG. 6B is a schematic diagram depicting a section cut by an alternate long and short dashed line indicated by 6B-6B shown in FIG. 6A. FIG. 6C is a schematic plan view for illustrating the fabrication process step of the semiconductor device, particularly the separation process step. FIG. 6D is a schematic diagram depicting a section cut by an alternate long and short dashed line indicated by 6D-6D shown in FIG. 6C. In the fabrication method of the second embodiment, since a dice bonding process step, a wire bonding process step (FIGS. 2A to 3B), and an external terminal forming process step (FIGS. 4A and 4B) are the same as those in the first embodiment, see the description in the first embodiment. As shown in FIGS. 6A and 6B, an encapsulation layer 70 for encapsulating a semiconductor chip 20 and bonding wires 40 joined to the semiconductor chip is formed. The encapsulation layer 70 is formed so as to expose first and second outermost leadframes 12a and 12b on end faces 20c and 20c of the semiconductor chip 20 and to cover two or more of the semiconductor chips on side faces 20d and 20d of the semiconductor chip 20, a preferable number is set freely. The encapsulation process step can be conducted by using the traditionally well-known encapsulation apparatus with the molds having the structure described on the first embodiment, other than forming a cavity that can house a plurality of the semiconductor chips bonded on leadframes 12, a preferable number is set freely. As a matter of course, the spaces between the plurality of the linear leadframes are buried with the encapsulation resin material by the encapsulation process step. Subsequently, all the leadframes 12 placed right under the second main surface 20b of the semiconductor chip 20 are cut at a scribe line A (see FIG. 6C) to form a groove part 60 as similar to the first embodiment. After that, as shown in FIGS. 6C and 6D, the semiconductor device 10 including the semiconductor chip 20 is separated into each piece (see FIGS. 6A to 6D) in which the encapsulation layer 70 and the leadframes 12 are cut along scribe lines C extended in the direction orthogonal to the first and second outermost leadframes 12a and 12b and set in the space between the semiconductor chips 20 and scribe lines D extended in the direction along the first and second outermost leadframes 12a and 12b. The difference between the configuration of the semiconductor device 10 thus obtained and that of the semiconductor device described in the first embodiment is in that the semiconductor device of the second embodiment itself is substantially in a nearly rectangular parallelepiped and has no projecting external terminals. For the separation process step, for example, the traditionally well-known dicing apparatus similar to that used in forming the groove part 60 can be used. According to the fabrication method of the semiconductor device of the second embodiment, in addition to the advantages obtained by the fabrication method of the first embodiment, the process step of forming the groove part 60 and the separation process step can be conducted by using the same apparatus. Furthermore, the separation process step can be made a simpler process step. Therefore, the semiconductor device can be fabricated more efficiently. 2-2. Semiconductor Device The configuration of the semiconductor device fabricated by the fabrication method of the second embodiment will be described with reference to FIGS. 7A, 7B and 7C. FIG. 7A is a schematic perspective view for illustrating the exemplary configuration of the semiconductor device 10 of the second embodiment 10. FIG. 7B is a schematic diagram depicting a section of the semiconductor device 10 cut by an alternate long and short dashed line indicated by 7B-7B shown in FIG. 7A. FIG. 7C is a plan view depicting the semiconductor device 10 seen from the bottom (external terminal side). In addition, the encapsulation part having the configuration different from that of the semiconductor device of the first embodiment will be described here, and the detailed description of the other same configuration as that of the first embodiment is omitted. As shown in FIGS. 7A and 7B, the encapsulation part 50 is formed in a nearly rectangular parallelepiped. The encapsulation part 50 encapsulates the semiconductor chip 20, the bonding wires 40 and the external terminals 14. The external terminals 14, that is, the first and second external terminals 14a and 14b are disposed so that the sections generated by the separation process step are exposed from both encapsulation part side faces 50b and 50b, respectively. Moreover, as shown in FIGS. 7B and 7C, the encapsulation part 50 is disposed so as to expose back sides 14ab and 14bb thereof. According to the semiconductor device of the second embodiment, in addition to the advantages obtained by the semiconductor device of the first embodiment, the semiconductor device can be formed further smaller because the external terminals 14 are not projected from the encapsulation part 50. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to a semiconductor device and a fabrication method thereof, particularly to a SON (Small Outline Non-Lead Package) type semiconductor device and a fabrication method thereof. 2. Description of the Related Art A semiconductor device is known in which an external electrode of a semiconductor chip is electrically connected to a conductor terminal with a bonding wire and the semiconductor chip, the bonding wire and the conductor terminal are encapsulated with an insulator. In the semiconductor device like this, a so-called SON type semiconductor device is known in which a conductor terminal is exposed from an insulator. Furthermore, in order to reduce the exposure failure of the conductor terminal of the SON type semiconductor device like this, a fabrication process of a conductor terminal is known in which the conductor terminal is formed with the use of a conductor that an adhesion to a substrate is reduced under a predetermined condition and the adhesion between the substrate and the conductor terminal is reduced for removal under a predetermined condition after its encapsulation process step (for example, see Patent Document 1). Patent Document 1 JP-A-2003-078076 | <SOH> SUMMARY OF THE INVENTION <EOH>In the fabrication process of the traditional SON type semiconductor device like this, a leadframe needs to be prepared with matching to the size of a semiconductor chip or the arrangement of electrode pads formed on the top surface of the semiconductor chip, that is, for every semiconductor chip of particular specifications. In addition, according to the traditional fabrication process, a dice bonding process step, a wire bonding process step, a resin encapsulation process step, and a separation process step cannot be combined into a series of process steps. Therefore, since semiconductor devices in midstream of fabrication dwell until they are processed by the subsequent process step, the time required to fabricate a semiconductor device is increased. The invention has been made in view of the problems. In order to solve the problems, a fabrication method of a semiconductor device according to the invention mainly includes the process steps below. More specifically, first, a plurality of linear leadframes is arranged side by side separately from each other. Then, a plurality of semiconductor chips having a first main surface with a plurality of electrode pads and a second main surface facing the first main surface is placed over a plurality of linear leadframes and separated from each other in the direction of extending the linear leadframes with the second main surface of each of the semiconductor chips mounted thereon. Furthermore, the plurality of the electrode pads is joined to the plurality of the linear leadframes with bonding wires. Moreover, an encapsulation part for encapsulating the semiconductor chip and the bonding wires and an interframe encapsulation part for burying a space between the adjacent linear leadframes exposed outside the encapsulation part are formed. Subsequently, a groove part for cutting all the linear leadframes placed right under the second main surface in the vertical direction to the direction of extending the linear leadframes. After that, the leadframes and the interframe encapsulation parts exposed between the plurality of the semiconductor chips are cut to separate into semiconductor devices having the semiconductor chip and a first external terminal row and a second external terminal row facing each other as sandwich the groove part. According to the fabrication method of the semiconductor device according to the invention, since the interval between the leadframes arranged is easily matched to the interval between the external terminals, leadframes do not need to be prepared for every semiconductor chip with particular specifications. Moreover, the dice bonding process step, the wire bonding process step, the resin encapsulation process step, and the separation process step can be conducted in a series of process steps on the plurality of the leadframes arranged. Therefore, the semiconductor devices in midstream of fabrication do not dwell until they are processed by the subsequent process step. Accordingly, many semiconductor devices can be fabricated efficiently for a short time. Furthermore, it also contributes to the reduction in the fabrication costs of the semiconductor device. | 20040123 | 20070206 | 20050512 | 69888.0 | 0 | TOLEDO, FERNANDO L | SEMICONDUCTOR DEVICE HAVING A SEMICONDUCTOR CHIP MOUNTED ON EXTERNAL TERMINALS AND FABRICATION METHOD THEREOF | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,762,661 | ACCEPTED | Environment detection system | An environment detection device for detecting a plurality of environmental conditions comprising a housing unit. The housing unit contains a plurality of sensors, a battery, and a memory storage device. The housing unit further includes a circuit board electrically connected to the plurality of sensors, the battery, and the memory storage device. The plurality of sensors includes a sunlight intensity sensor, a timer, a temperature sensor, and a moisture sensor. Additionally, a method is provided for determining vegetation capable of thriving in certain environmental conditions. The method includes sensing the environmental conditions, storing the environmental conditions on a memory storage device, and downloading the environmental conditions to a database, wherein the database displays a list of vegetation capable of surviving in the plurality of environmental conditions. | 1. An apparatus for detecting a plurality of environmental conditions comprising: a housing unit containing at least one sensor selected from a group consisting of a temperature sensor, and a light sensor; a memory storage device disposed in said housing unit; a circuit board electrically connected to said at least one sensor and the memory storage device, and contained within the housing unit; and at least one moisture probe physically connected to the housing unit, and electrically connected to the circuit board. 2. The apparatus of claim 1 wherein said at least one sensor includes a sunlight intensity sensor and a temperature sensor. 3. The apparatus of claim 1 wherein the housing unit further comprises an accessible compartment providing access to the memory storage device. 4. The apparatus of claim 1 wherein the memory storage device interfaces with the circuit board through a universal serial bus (USB). 5. The apparatus of claim 1 further comprising a global positioning satellite (GPS) system which provides geographic information. 6. The apparatus of claim 1 wherein the light sensor is an ultraviolet sensor and the temperature sensor is a thermometer. 7. The apparatus of claim 1 further comprising a battery in the housing unit. 8. The apparatus of claim 7 further comprising a battery charger connectable to said housing unit to recharge the battery. 9. The apparatus of claim 7 further comprising at least one solar cell for recharging the battery. 10. A method of determining vegetation capable of thriving in a plurality of environmental conditions, comprising the steps of: sensing the plurality of environmental conditions with an environment detection apparatus; storing the plurality of environmental conditions on a memory storage device; and downloading the plurality of environmental conditions to a database, wherein the database displays a list of vegetation capable of surviving in the plurality of stored environmental conditions. 11. The method of claim 10 wherein the plurality of environmental conditions comprises a geographic location, a sunlight intensity reading, a date and time reading, a temperature reading, and a moisture reading. 12. The method of claim 11 wherein at least one ultraviolet sensor determines the sunlight intensity reading, and at least one moisture probe determines the moisture reading. 13. The method of claim 12 wherein a global positioning satellite system determines the geographic location, the date and time reading, and the temperature reading. 14. The method of claim 12 wherein the user manually inputs the geographic location into the database, a timer determines the date and time reading, and a thermometer determines the temperature reading. 15. A control system for using an environment detection apparatus as an activation device for a sprinkler system comprising: at least one sensor determining at least one environmental condition; at least one logical operation producing an output to an actuator based on the at least one environmental condition; and the actuator activating the sprinkler system based on the output of the at least one logical operation. 16. The control system of claim 15 wherein the at least one environmental condition is a sunlight intensity reading. 17. The control system of claim 16 wherein at least one ultraviolet sensor determines the sunlight intensity reading. 18. The control system of claim 15 wherein the at least one environmental condition is a moisture reading. 19. The control system of claim 18 wherein a moisture probe determines the moisture reading. 20. The control system of claim 15 wherein the at least one environmental condition is a weather forecast which is read from a remote device. | FIELD OF THE INVENTION The present invention relates to an environment detection system. More specifically, the present invention relates to a method and apparatus for determining environmental conditions suitable for growing plant life. BACKGROUND OF THE INVENTION In the past, plant enthusiasts have relied on books or horticulturalists to know the environmental conditions in which certain plants could grow. These conditions include geographic location, the amount of sunlight, temperature, and the amount of moisture in the ground. Excluding the geographic location, these conditions change frequently. For example, the amount of sunlight and the temperature in an area changes as the season changes. Furthermore, both temperature and sunlight change as the day progresses. These frequent changes make monitoring the conditions of the planting location very difficult to do by inspection. Not knowing the precise environmental conditions of a specific planting location can cause a few problems. First, the vegetation the planter chooses may not survive in the area. Second, if planted in the wrong area, some plants will overtake other vegetation growing in that area. Third, the planter can experience some frustration in having to constantly spend money trying to find the right plants for growing in a particular area. These problems give rise to a much needed solution. An apparatus that is capable of accurately determining certain geographical conditions, and a method thereof, that would reduce the problems and frustration of planting vegetation in a specified area. SUMMARY OF THE INVENTION The present invention relates to an apparatus for detecting a plurality of environmental conditions utilizing a housing unit having a plurality of sensors, sensing, for example, sunlight, temperature, and moisture of an area to be landscaped. The housing unit further includes a battery and a memory storage device. A circuit board is electrically connected to the plurality of sensors, the battery, and the storage device, and is contained within the housing unit. The moisture sensor is provided in the form of a moisture probe. The moisture probe is physically connected to the housing unit, and electrically connected to the circuit board. The present invention further relates to a method of determining vegetation capable of thriving in a plurality of environmental conditions, comprising the steps of sensing the plurality of environmental conditions with an environment detection apparatus, storing the plurality of environmental conditions on a memory storage device, and downloading the plurality of environmental conditions to a database, wherein the database displays a list of vegetation capable of surviving in the sensed environmental conditions. Finally, the present invention relates to a control system for using an environment detection apparatus as an activation device for a sprinkler system comprising at least one sensor for determining at least one environmental condition, at least one logical operation producing an output to an actuator based on the at least one environmental condition, and the actuator activating the sprinkler system based on the output of the at least one logical operation. Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: FIG. 1 is a plan view of a preferred embodiment of an environment detection apparatus constructed in accordance with the present invention; FIG. 2 is a plan view of an alternative embodiment of an environment detection apparatus constructed in accordance with the present invention; FIG. 3 is a schematic diagram of a control system of an environment detection apparatus constructed in accordance with the present invention; and FIG. 4 is a plan view of an alternative embodiment of an environment detection apparatus constructed in accordance with the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. FIG. 1 depicts an environment detection device 10. Environment detection device 10 reads various signals from various sensors based on the environmental conditions surrounding device 10. The sensors are contained within a housing unit 12. Additionally, housing unit 12 contains a battery 14, a circuit board 16, and a memory storage device 18 that is accessible in housing unit 12 by a user. The first sensor in housing unit 12 is a light sensor, such as an ultraviolet sensor 20. Ultraviolet sensor 20 is placed in housing unit 12 in such a way that it is able to receive sunlight. For the preferred embodiment, housing unit 12 has a clear top portion 21, allowing light to travel to ultraviolet sensor 20. Furthermore, ultraviolet light sensor 20 is preferably positioned at the top of housing unit 12 to ensure that it can accurately register any amount of light in the area. Those skilled in the art recognize an ultraviolet sensor 20 is well known. The next sensor is a temperature sensor, such as a digital thermometer 22 for detecting the temperature of the surrounding area. Additionally, a timer, such as a digital clock 24 interfaces with circuit board 16. Those skilled in the art recognize that thermometer 22 and clock 24 are well known, and widely used components. The fourth sensor is a moisture probe 26. Moisture probe 26 measures the amount of conductivity in the ground. More moisture in the ground, for example, means more water in the ground. This lowers the electrical resistance of the ground, thus raising the ground's conductivity. Although the preferred embodiment shows two moisture probes 26, any number could be used depending on the size of the area being measured. The sensors are connected to circuit board 16. Circuit board 16 processes the data received by the sensors by means of a microprocessor, and routes the information to a memory storage device (memory) 18. Memory 18 connects to device 10 through any number of different protocols, such as a universal serial bus (USB) connection, to allow easy removal and transfer to a computer. Many different memory storage devices 18 are available, including USB removable flash memory devices better known as jump drives to those skilled in the art. Once the data from the sensors has been acquired and downloaded to memory 18, the user removes memory 18 from device 10 and connects it to a computer. Alternatively, device 10 may contain a wireless transmitter to transmit the data from the sensors to a wireless receiver connected to a computer. Either method delivers the data collected by the sensors to a database on the computer at step S1 in FIG. 5. This processor prompts the user for various inputs, such as data group name S2 and geographic location S3. The processor then determines the plants meeting the sensed conditions (light, moisture, etc.) and geographic location. The user then inputs the general types of vegetation desired (e.g., plants, shrubs, trees (deciduous or evergreen), flowers (annuals or perennials) S5, SD. The database then analyzes the data recorded from the sensors to provide a list of vegetation that can thrive in those conditions S7. Other restrictions or parameters can be provided for limiting or narrowing down the list of vegetation, including height, width restrictions, color, type of soil, and other conditions. According to another aspect of the present invention, the device 10 includes a global positioning satellite (GPS) system receiver 28 connected to circuit board 16 in addition to the other sensors. The benefit to using GPS system receiver 28 is that it is capable of determining the time, location, and temperature with decent accuracy. GPS receivers, in general, receive signals from a series of satellites orbiting the earth to acquire various data. Typically, GPS receivers are used to determine specific global coordinates, future weather forecasts, and any other information broadcast from the satellites. Additionally, many GPS receivers include on-board thermometers and clocks that operate similarly to those well known in the art. Therefore, GPS system receiver 28 may eliminate the user from having to input geographical location information into the database, as well as performing the function of the thermometer 22 and clock 24. Device 10 stores various data helpful in planting future vegetation, however, this data can also be useful for watering the vegetation after it has been planted. FIG. 2 shows a control system 30 using device 10 as means to actuate a sprinkler system. First, the data collected from the sensors acts as inputs 32 to the control system 30. This data includes a sunlight intensity reading 20, a date and time reading 24, a temperature reading 22, and a moisture reading 26. These inputs travel along data lines 34 to the microprocessor on circuit board 16. The microprocessor analyzes the inputs 32 by using a series of “If/Then” logic statements 36 to determine if the vegetation needs to be watered. If the logic statements 36 determine watering is necessary, an output signal is sent to an actuator 38, which activates the sprinkler system. Although thermometer 22 and clock 24 could be used as the sensors to collect the temperature and time reading, respectively, GPS system receiver 28 would be more beneficial in terms of device 10 actuating a sprinkler system. GPS system receiver 28 could determine the temperature and time, as well as receive future weather forecasts. This information would be useful when determining whether or not to water the vegetation. For example, if it is determined based upon the moisture reading that the vegetation needs to be watered, an “If/Then” logic statement 36 may be included that follows the following pattern: “if” the forecast equals “rain,” “then” delay actuation of the sprinkler system. Other time constraint type “If”/“Then” logic statements 36 are implemented in case the forecast of “rain” is incorrect and therefore, the time constraint type “If”/“Then” logic statements 36 limit the amount of time that expires prior to watering of the vegetation. With this type of system, a more efficient sprinkler system is provided. Referring now to FIG. 3, device 10 is powered by either rechargeable or non-rechargeable batteries 14. For rechargeable batteries 14, device 10 employs a charging caddy 40 that connects to device 10 through moisture probes 26. Charging caddy 40 further connects to a wall outlet by means of a plug 44. As shown in FIG. 4, charging caddy 40 has a built in rectifier 46 to convert an AC voltage from wall outlet 42 to a DC voltage to charge batteries 14, as well as additional circuitry and components to charge the batteries, which is well known in the art. Furthermore, device 10 may contain solar cells 48 to relieve a portion of the energy drain on batteries 14 while device 10 is located outside in sunlight. Solar cells 48 use sunlight to power device 10, relieving battery 14 of having to supply all the power. This allows device 10 to be placed outside for longer periods of time, thus allowing device 10 to collect more data. The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention. | <SOH> BACKGROUND OF THE INVENTION <EOH>In the past, plant enthusiasts have relied on books or horticulturalists to know the environmental conditions in which certain plants could grow. These conditions include geographic location, the amount of sunlight, temperature, and the amount of moisture in the ground. Excluding the geographic location, these conditions change frequently. For example, the amount of sunlight and the temperature in an area changes as the season changes. Furthermore, both temperature and sunlight change as the day progresses. These frequent changes make monitoring the conditions of the planting location very difficult to do by inspection. Not knowing the precise environmental conditions of a specific planting location can cause a few problems. First, the vegetation the planter chooses may not survive in the area. Second, if planted in the wrong area, some plants will overtake other vegetation growing in that area. Third, the planter can experience some frustration in having to constantly spend money trying to find the right plants for growing in a particular area. These problems give rise to a much needed solution. An apparatus that is capable of accurately determining certain geographical conditions, and a method thereof, that would reduce the problems and frustration of planting vegetation in a specified area. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention relates to an apparatus for detecting a plurality of environmental conditions utilizing a housing unit having a plurality of sensors, sensing, for example, sunlight, temperature, and moisture of an area to be landscaped. The housing unit further includes a battery and a memory storage device. A circuit board is electrically connected to the plurality of sensors, the battery, and the storage device, and is contained within the housing unit. The moisture sensor is provided in the form of a moisture probe. The moisture probe is physically connected to the housing unit, and electrically connected to the circuit board. The present invention further relates to a method of determining vegetation capable of thriving in a plurality of environmental conditions, comprising the steps of sensing the plurality of environmental conditions with an environment detection apparatus, storing the plurality of environmental conditions on a memory storage device, and downloading the plurality of environmental conditions to a database, wherein the database displays a list of vegetation capable of surviving in the sensed environmental conditions. Finally, the present invention relates to a control system for using an environment detection apparatus as an activation device for a sprinkler system comprising at least one sensor for determining at least one environmental condition, at least one logical operation producing an output to an actuator based on the at least one environmental condition, and the actuator activating the sprinkler system based on the output of the at least one logical operation. Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. | 20040122 | 20070612 | 20050728 | 60719.0 | 5 | TAYLOR, VICTOR J | ENVIRONMENT DETECTION SYSTEM | SMALL | 0 | ACCEPTED | 2,004 |
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10,762,732 | ACCEPTED | Strap sack | Housing for containing excess cargo tie-down material, and for containing the locking mechanism to reduce its exposure to the environmental elements. The housing is in the form of a generally flat portion and a sack made of durable material. The sack is configured to receive excess strap or other tie-down element, and to neatly fold about the locking mechanism to protect the same from severe environmental conditions. The generally flat portion includes opposite free end flaps that when folded towards each other, envelope the locking mechanism and sack. | 1. A housing adapted to enclose a tie-down device comprising a length of strap and a locking mechanism, said housing comprising a sack having a volume sufficient to contain a portion of said length of strap, and a generally flat portion adapted to contain said locking mechanism, said sack being foldable upon said flat portion and securable thereon. 2. The housing of claim 1, further comprising a pair of spaced slits in said generally flat portion of said housing. 3. the housing of claim 2, wherein each of said slits is adapted to receive a portion of said length of strap. 4. The housing of claim 1, wherein said generally flat portion has opposite free ends, and wherein said opposite free ends are adapted to be folded onto one another to enclose said sack. 5. A cargo tie-down system comprising, in combination, a tie down device comprising a tie-down strap and a locking mechanism to tension said strap, and a housing for enclosing said locking mechanism and for securing any excess tie-down strap formed after tensioning said strap with said locking mechanism, said housing comprising a sack having a volume sufficient to contain said excess tie-down strap, and a generally flat portion adapted to contain said locking mechanism, said sack being foldable upon said flat portion and securable thereon. 6. The cargo tie-down system of claim 5, wherein said generally flat portion comprises a pair of spaced slits through which said tie-down strap is threaded. 7. The cargo tie-down system of claim 5, wherein said generally flat portion has opposite free ends, and wherein said opposite free ends are adapted to be folded onto one another to enclose said sack. 8. The cargo tie-down system of claim 5, wherein said generally flat portion has opposite free ends, and wherein said opposite free ends are adapted to be folded onto one another to enclose said locking mechanism. | BACKGROUND OF THE INVENTION Tie-down devices for securing cargo on vehicles such as railway cars, trailers or truck flatbeds or decks are well known. Typically the devices include a winch or a ratchet which receives a tie-down element such as a cable, chain, rope, strap or the like. The tie-down element is secured to one side of the vehicle bed, draped over the cargo, and attached to the other side of the bed. Once the cargo is secured beneath the tie-down element, the winch or ratchet is actuated to tension the tie-down element over the cargo, securing the same in place. Since the dimensions of various cargoes can vary considerably, the length of the tie-down element necessary to secure the cargo also varies. As the tie-down element is tensioned by the winch or ratchet, excess strap that is not under tension results. This excess must be secured in some fashion to prevent it from freely flapping as the vehicle travels, as this can cause damage to the cargo, the vehicle, the strap or the tie-down element itself. Moreover, the tensioning mechanism typically includes a locking mechanism that can freeze upon exposure to freezing rain or snow. The tie-down element also can freeze. In addition, the locking mechanism tends to roll on its side or top due to the cargo shifting during transit or during tightening of the tie-down element. Any movement of the locking mechanism can scratch or damage the cargo. It is therefore an object of the present invention to provide a device for securing excess tie-down members in a convenient and easy fashion. It is a further object of the present invention to provide a device that protects the cargo from being scratched or damaged by the locking mechanism. It is a still further object of the present invention to provide a device that protects the locking mechanism and tie-down element from deleterious environmental conditions, thereby preventing the locking mechanism and tie-down element from freezing or other damage that would occur were it exposed to severe environmental conditions such as snow or freezing rain. SUMMARY OF THE INVENTION The problems of the prior art have been overcome by the present invention, which provides a versatile housing for containing excess tie-down material, and for containing the locking mechanism to reduce its exposure to the environmental elements. The housing is preferably in the form of a generally flat portion and a sack made of durable material. The sack is configured to receive excess strap or other tie-down element, and to neatly fold about the locking mechanism to protect the same from severe environmental conditions. The generally flat portion includes opposite free end flaps that when folded towards each other, envelope the locking mechanism and sack. The device of the present invention can be retrofitted with existing tie-down straps and locking mechanisms, BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded view showing the housing, tie-down element and locking mechanism in accordance with one embodiment of the present invention; FIG. 2 is a top view of a tie-down system installed in the housing in accordance with one embodiment of the present invention; FIG. 3 is a top view of the closed housing showing a tie-down system installed in accordance with one embodiment of the present invention; and FIG. 4 is a top view of the housing in accordance with one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION Turning now to FIG. 1, there is shown a tie-down assembly including a conventional ratchet-type locking mechanism 10, strap 12 appropriately threaded in the locking mechanism 10, and hooks 13 attached to the strap at free ends thereof. Those skilled in the art will appreciate that although a strap is shown as the tie-down element, other tie-down elements can be used, including chains, ropes, cables or cords, and that the term “strap” as used herein encompasses such alternatives. Similarly, although hooks 13 are shown as the means for attaching the tie-down element to the vehicle, other attaching devices known to those skilled in the art are also within the scope of the present invention. The present invention is also not limited to any particular locking mechanism design; winches, cams, over-center devices, etc. could be used in addition to the ratchet-type illustrated. The preferred embodiment of the housing 20 is shown in FIG. 1 in a partially assembled condition. Suitable housing materials are materials that are weather resistant, durable and capable of being folded or otherwise configured into a compact form. Exemplary materials are woven synthetic fiber such as Marine grade polyester fabric, leather, fiberglass cloth, cotton, nylon, vinyl, rubber, foam, woven cloths and non-woven sheet materials. Woven synthetic polyester fabric is particularly preferred in view of its durability, versatility and availability in popular colors. The housing includes a generally flat portion and an integral sack 21 having a sufficient volume to receive and store any excess strap 12 generated after tensioning of the tie-down device over the cargo being secured. The sack 21 preferably is positioned at or near the centerline of the length “l” of the housing 21, and has one open end to receive the excess strap. Positioning the sack 21 on the centerline allows it to easily fold over and onto the locking mechanism 10. It is positioned with respect to the remainder of the housing 20 (the generally flat portion) so that it can be folded over the remainder of the housing 20 to effectively close the open end and secure the strap inside the sack. The height “h” of the opening of the sack 21 is the same as or less than the width of the remainder of the housing 20 (i.e., width “w” shown in FIG. 1), so that upon folding the sack 21 onto the remainder of the housing 20, the opening of the sack 21 does not extend beyond the housing 20. Similarly, the depth “d” of the sack 21 is less than length “l” of the remainder of the housing 20. FIG. 4 illustrates the housing prior to assembly. The sack 21 is assembled by folding the sides 90° along the dotted lines and then securing the sides, such as by sewing with high strength synthetic thread such as nylon. Thus, edge A is secured to edge B, edge C to edge D, edge E to edge F and edge G to edge H. Alternatively, the sides could be secured by fusion welding, bonding, stapling, interweaving or riveting. The remainder of the housing 20 includes means for securing the opposite longitudinal ends 20A, 20B, together. A preferred means of securing these ends is with strips of hooks and loops such as VELCRO strips. Thus, one of the strips of hooks or loops is secured to the upper surface of the housing 20 at or near the end 20A, and the other of the strips is secured to the opposite under surface at or near the end 20B. Upon folding the ends 20A, 20B toward one another, the hooks and loops will engage and secure the housing 20 together as discussed in greater detail below. Other suitable means to secure the ends of the housing to one another include adhesive, snaps, buttons, zippers, laces, magnets, elastics, springs and hooks, spring-loaded clips and clamps, toggle clamps or latches, suction cups, locks, screws, buckles, draw strings, etc. Any of these also could be used to close the sack 21 if desired. The housing 20 includes a pair of slits 28A, 28B penetrating through the housing material. The slits are suitably dimensioned to receive the hooks 13 and strap 12, which are threaded through the slits as best seen in FIG. 2. The slits can be formed in the housing 20 by any suitable means, such as by cutting. Where necessary or desired, the edges of the slits can be reinforced to prevent the housing from ripping further. Preferably the distance “s” between the slits 28A and 28B is sufficient to accommodate the locking mechanism 10 while still allowing the strap 12 to freely move through the slits, again as seen in FIG. 2. Preferably the slits 28A and 28B are aligned directly across from one another (i.e., are parallel and not offset from one another), again to ensure that the strap 12 is allowed to move freely through the slits. Preferably the slits are positioned on the approximate centerline of the length “l” of the housing 21, so that the housing can be opened and closed easily while the locking mechanism is tight against the cargo. Although slits are the preferred form of the apertures through the housing 20, other forms, regular or irregular, can be used without departing from the spirit and scope of the present invention. The housing 20 also includes a free end flap 27 with no integral means of securement attached to the generally flat portion opposite the sack 21, at or near the centerline of the length “l” of the housing. The width of the flap 27 is preferably equal to or substantially equal to the width of the sack 21, and its length is sufficient so that when it is folded over onto the locking mechanism 10 and the sack is folded onto it, and finally the end flaps 20A, 20B are folded and secured, it will be held securely and not come loose. The flap 27 functions to cover the area of the locking mechanism 10 that is not covered by the folded and secured sack 21, thereby completely shielding the locking mechanism 10 from deleterious environmental conditions and ensuring that the locking mechanism 10 is completely encompasses to further protect the cargo from being scratched or otherwise damaged by it. The housing 20 is attached to the tie-down device by inserting each of hooked ends 13 through a respective slot, and pulling the strap 13 attached to the hooks through the slits until the locking mechanism 10 is sitting flat against the surface of the housing between the slits 28A and 28B. The hooks 13 are secured to the vehicle, and the cargo is secured by actuating the locking mechanism to tighten the strap 12 over the cargo. Excess strap 12 remaining after the tightening operation is fed into the sack 21. The free end flap is then folded 180° over the locking mechanism as indicated by arrow (1) in FIG. 2. The sack 21 is then folded 180° over the locking mechanism 10, as illustrated by arrow (2) in FIG. 2. One end 20B is then folded 180° over onto the sack 21, as illustrated by arrow (3) in FIG. 2. The opposite end 20A is then folded 180° onto the end 20B as illustrated by arrow (4) in FIG. 2 (those skilled in the art will appreciate that the order of folding flaps 20A and 20B could be reversed if the functional portions of the VELCO are reversed). The hook and loop strips thereby contact each other and engage, securing the housing over the locking mechanism and sack 21, to form an enclosed protective housing as shown in FIG. 3. Those skilled in the art will appreciate that the order of the foregoing assembly can vary, particularly if means other than hooks and loops is used to secure the ends of the housing 20 to one another. | <SOH> BACKGROUND OF THE INVENTION <EOH>Tie-down devices for securing cargo on vehicles such as railway cars, trailers or truck flatbeds or decks are well known. Typically the devices include a winch or a ratchet which receives a tie-down element such as a cable, chain, rope, strap or the like. The tie-down element is secured to one side of the vehicle bed, draped over the cargo, and attached to the other side of the bed. Once the cargo is secured beneath the tie-down element, the winch or ratchet is actuated to tension the tie-down element over the cargo, securing the same in place. Since the dimensions of various cargoes can vary considerably, the length of the tie-down element necessary to secure the cargo also varies. As the tie-down element is tensioned by the winch or ratchet, excess strap that is not under tension results. This excess must be secured in some fashion to prevent it from freely flapping as the vehicle travels, as this can cause damage to the cargo, the vehicle, the strap or the tie-down element itself. Moreover, the tensioning mechanism typically includes a locking mechanism that can freeze upon exposure to freezing rain or snow. The tie-down element also can freeze. In addition, the locking mechanism tends to roll on its side or top due to the cargo shifting during transit or during tightening of the tie-down element. Any movement of the locking mechanism can scratch or damage the cargo. It is therefore an object of the present invention to provide a device for securing excess tie-down members in a convenient and easy fashion. It is a further object of the present invention to provide a device that protects the cargo from being scratched or damaged by the locking mechanism. It is a still further object of the present invention to provide a device that protects the locking mechanism and tie-down element from deleterious environmental conditions, thereby preventing the locking mechanism and tie-down element from freezing or other damage that would occur were it exposed to severe environmental conditions such as snow or freezing rain. | <SOH> SUMMARY OF THE INVENTION <EOH>The problems of the prior art have been overcome by the present invention, which provides a versatile housing for containing excess tie-down material, and for containing the locking mechanism to reduce its exposure to the environmental elements. The housing is preferably in the form of a generally flat portion and a sack made of durable material. The sack is configured to receive excess strap or other tie-down element, and to neatly fold about the locking mechanism to protect the same from severe environmental conditions. The generally flat portion includes opposite free end flaps that when folded towards each other, envelope the locking mechanism and sack. The device of the present invention can be retrofitted with existing tie-down straps and locking mechanisms, | 20040122 | 20070123 | 20050728 | 72813.0 | 0 | RODRIGUEZ, RUTH C | STRAP SACK | SMALL | 0 | ACCEPTED | 2,004 |
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10,762,767 | ACCEPTED | Peripheral device feature allowing processors to enter a low power state | If a USB device is turned off or is not active, the device may be electrically disconnected from a USB host controller. The device may be electrically disconnected through a physical interface on the device. In some embodiments, if the device becomes active during a wait period (e.g., 2-3 seconds) prior to electrically disconnecting the device, the device may not be electrically disconnected. In some embodiments, when the device is electrically disconnected from the USB host controller and no system activity of a bus mastering peripheral is occurring, the CPU may enter a low power state if other conditions are met. In some embodiments, if the USB device becomes active after electrically disconnecting, the electrical disconnection may be discontinued. | 1. A system, comprising: a processor; a host controller coupled to the processor; a device coupled to the host controller; and wherein the device is electrically disconnected from the host controller if the device is not in an active state. 2. The system of claim 1, wherein the device is a card reader and the active state comprises a memory card in the card reader. 3. The system of claim 1, wherein the device is a hub and the active state comprises a second device attached to the hub. 4. The system of claim 1, wherein the device is not in an active state if the device has not been used in a second specified amount of time. 5. The system of claim 1, wherein if the device is not in an active state, the device is electrically disconnected after a wait period, wherein if the device becomes active during the wait period, the device is not electrically disconnected. 6. The system of claim 1, wherein when the device is electrically disconnected from the host controller, the device does not cause bus activity. 7. The system of claim 1, wherein the device is a card reader, and if a memory card is inserted into the card reader and the card reader has been previously electrically disconnected, the electrical disconnect from the host controller is discontinued. 8. The system of claim 1, wherein if the processor is in a low power state, the processor exits the low power state if an electrical disconnect is discontinued. 9. The system of claim 1, wherein the device is a card reader and the card reader is permanently coupled to a portable computer computer. 10. The system of claim 1, wherein a sideband signal is used to signal the device to electrically reconnect after the device has been electrically disconnected. 11. The system of claim 1, wherein the host controller provides a peripheral bus interface for the device. 12. The system of claim 1, wherein electrically disconnecting the device comprises electrically removing a pull up resistor from a D+ line. 13. The system of claim 1, wherein electrically disconnecting the device comprises tri-stating a D+ line and a D− line. 14. A method, comprising: detecting whether a device coupled to a host controller is in an active state; if the device is not in an active state, electrical disconnecting the device from a host controller; and if the device is in an active state, maintaining an electrical connection between the device and the host controller. 15. The method of claim 14, wherein the device is a card reader, and the active state comprises a memory card inserted in the card reader. 16. The method of claim 14, wherein the device is a hub, and the active state comprises a second device coupled to the hub. 17. The method of claim 16, wherein the second device is coupled to the hub and a sideband signal from a computer signals the hub to electrically disconnect and wherein a sideband signal from the computer signals the hub to electrically reconnect at a later time. 18. The method of claim 16, wherein the second device is coupled to the hub and a sideband signal from a computer signals the hub to enter a reduced functionality state and wherein a sideband signal from the computer signals the hub to exit the reduced functionality state at a later time. 19. The method of claim 14, wherein the device is not in an active state if the device has not been used in a second specified amount of time. 20. The method of claim 14, wherein if the device is not in an active state, the device is electrically disconnected after a wait period, wherein if the device becomes active during the wait period, the device is not electrically disconnected. 21. The method of claim 14, wherein if no devices are coupled to the host controller the host controller does not create bus activity. 22. The method of claim 14, wherein the device is a card reader, and if a memory card is inserted into the card reader after the card reader has been electrically disconnected, the electrical disconnect is discontinued. 23. The method of claim 14, wherein electrical disconnecting the device from the host controller makes it appear to the host controller that a device is not coupled to the host controller. 24. The method of claim 14, wherein the device is a card reader and wherein the card reader is not in an active state if the card reader has not been accessed in a second specified amount of time. 25. The method of claim 24, wherein a sideband signal is used to signal the card reader to electrically reconnect when an attempt is made to access a card after the card reader has been electrically disconnected with a card inserted into the card reader. 26. The method of claim 14, wherein the host controller provides a peripheral bus interface for the device. 27. The method of claim 14, wherein electrically disconnecting the device comprises electrically removing a pull up resistor from a D+ line. 28. The method of claim 14, wherein electrically disconnecting the device comprises tri-stating a D+ line and a D− line. 29. A system, comprising: a processor; a host controller coupled to the processor; a device detect logic; a hub electrically coupled to the host controller and device detect logic; an auto detach logic coupled to the hub; and wherein the auto detach logic initiates an electrical disconnect of the hub from the host controller if the device detect logic does not detect a device on the hub. 30. The system of claim 29, wherein when the hub is electrically disconnected, the hub does not create bus activity until a device is coupled to the hub. 31. The system of claim 29, wherein if a device is coupled to the hub, the auto detach logic discontinues the electrical disconnect of the hub from the host controller. 32. The system of claim 29, wherein if the processor is in a low power state, the processor exits the low power state if the electrical disconnect is discontinued. 33. The system of claim 29, wherein the processor is in a portable computer computer. 34. The system of claim 29, wherein the hub is permanently coupled to a portable computer computer. 35. The system of claim 29, wherein the device comprises a keyboard, a mouse, a speaker, a microphone, a printer, a camera, a scanner, or a touchscreen. 36. The system of claim 29, wherein the device is a USB device and is coupled to the hub by plugging the device into a USB connection. 37. The system of claim 29, wherein the electrical disconnect comprises tristating the full speed (FS) and high speed (HS) transceivers. 38. The system of claim 29, wherein the electrical disconnect is enabled by a configuration bit in an Electrically Erasable Programmable Read-Only Memory (EEPROM). 39. The system of claim 29, wherein if a device is not detected on the hub, the hub is electrically disconnected after a wait period, wherein if a device is attached to the hub during the wait period, the hub is not electrically disconnected. 40. A method, comprising: detecting whether a device is coupled to a hub; if a device is not coupled to the hub, electrical disconnecting the hub from a host controller; and if a device is coupled to the hub, maintaining a connection between the hub and the host controller. 41. The method of claim 40, wherein if a device is reconnected to the hub, the electrical disconnect is not maintained and if the processor is in a low power state, the processor awakes from the low power state. 42. The method of claim 41, wherein the device coupled to the hub comprises a keyboard, a mouse, a speaker, a microphone, a printer, a camera, a scanner, or a touchscreen. 43. The method of claim 40, wherein electrical disconnecting comprises tristating FS and HS transceivers. 44. The method of claim 40, wherein electrical disconnect is enabled by a configuration bit in an EEPROM. 45. The method of claim 40, wherein electrical disconnecting the hub from the host controller makes it appear to the host controller that a device is not coupled to the host controller. 46. The method of claim 40, wherein if a device is not coupled to the hub, the hub is electrically disconnected after a wait period, wherein if a device is coupled to the hub during the wait period, the hub is not electrically disconnected. 47. A carrier medium comprising program instructions, wherein the program instructions are executable to: detect whether a device coupled to a host controller is in an active state; if the device is not in an active state, electrical disconnect the device from a host controller; and if the device is in an active state, maintain an electrical connection between the device and the host controller. 48. The carrier medium of claim 47, wherein the device is a card reader, and the active state comprises a memory card inserted in the card reader. 49. The carrier medium of claim 47, wherein the device is a hub, and the active state comprises a second device coupled to the hub. 50. The carrier medium of claim 47, wherein the device is not in an active state if the device has not been used in a second specified amount of time. 51. The carrier medium of claim 47, wherein if the device is not in an active state, the device is electrically disconnected after a wait period, wherein if the device becomes active during the wait period, the device is not electrically disconnected. 52. The carrier medium of claim 47, wherein if no devices are coupled to the host controller the host controller does not create bus activity. 53. The carrier medium of claim 47, wherein the device is a card reader, and if a memory card is inserted into the card reader after the card reader has been electrically disconnected, the electrical disconnect is discontinued. 54. The carrier medium of claim 47, wherein electrical disconnecting the device from the host controller makes it appear to the host controller that a device is not coupled to the host controller. 55. The carrier medium of claim 47, wherein the device is a card reader and wherein the card reader is not in an active state if the card reader has not been accessed in a second specified amount of time. 56. The carrier medium of claim 47, wherein a sideband signal is used to signal the card reader to electrically reconnect when an attempt is made to access a card after the card reader has been electrically disconnected with a card inserted into the card reader. 57. The carrier medium of claim 47, wherein the host controller provides a peripheral bus interface for the device. 58. The carrier medium of claim 47, wherein electrically disconnecting the device comprises electrically removing a pull up resistor from a D+ line. 59. The carrier medium of claim 47, wherein electrically disconnecting the device comprises tri-stating a D+ line and a D− line. | BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to the field of computer systems and, more particularly, to peripheral devices. 2. Description of the Related Art The Universal Serial Bus (USB) allows coupling of peripheral devices to a computer system. USB is a serial cable bus for data exchange between a host computer and a wide range of simultaneously accessible devices. The bus allows peripherals to be attached, configured, used, and detached while the host is in operation. For example, a card reader for reading flash memory cards may be coupled to a host computer through the USB. USB based systems may require that a USB host controller be present in the host system, and that the operating system (OS) of the host system support USB and USB Mass Storage Class Devices. A USB hub may be coupled to a USB host controller to allow multiple USB devices to be coupled to the host system through the USB host controller. In addition, other USB hubs may be coupled to the USB hub to provide additional USB device connections to the USB host controller. In recent years the electronics marketplace has seen a proliferation of appliances and personal electronics devices that use solid-state memory. For example, traditional film cameras have been losing market share to digital cameras capable of recording images that may be directly downloaded to and stored on personal computers (PCs). The pictures recorded by digital cameras can easily be converted to common graphics file formats such as Joint Photographic Experts Group (JPEG), Graphic Interchange Format (GIF) or Bitmap (BMP), and sent as e-mail attachments or posted on web pages and online photo albums. Many digital cameras are also capable of capturing short video clips in standard digital video formats, for example Moving Picture Experts Group (MPEG), which may also be directly downloaded and stored on personal computers (PCs) or notebook computers. Other devices that typically use solid-state memory include personal digital assistants (PDAs), pocket PCs, video game consoles and Moving Picture Experts Group Layer-3 Audio (MP3) players. The most widely used solid-state memory devices include flash-memory chips configured on a small removable memory card, and are commonly referred to as flash-memory cards. The majority of flash-memory cards currently on the market are typically one of: Compact Flash™, MultiMediaMemory™ memory card (MMC) and the related Secure Digital Memory card (SD), SmartMedia™ memory card (SM), xD Picture Cards™ (xD), and Memory Stick™. Most digital cameras, for example, use Compact Flash™ memory cards to record images. Many PDA models use Memory Stick™ memory cards to hold data. Some MP3 players store music files on SM memory cards. Generally, data saved by PDAs and other handheld devices using flash-memory cards are also transferred or downloaded to a PC. In the present application, the term “flash-memory” is intended to have the full breadth of its ordinary meaning, which generally encompasses various types of non-volatile solid-state memory devices as described above. Typically, a flash-memory card can easily be removed from the utilizing device. For example, a Compact Flash™ memory card can be removed from a digital camera much like film is removed from a standard camera. The flash-memory card can then be inserted into an appropriate flash-memory card reader coupled to a PC, and the image files directly copied to the PC. It should be noted that while a majority of smaller hand-held computers and PDAs have slots that receive Compact Flash™ memory cards, currently, most PCs do not, hence the need for a flash-memory card reader connecting to the PC. Most recently the preferred interface between flash-memory card readers and PCs has been the Universal Serial Bus, where the flash-memory card reader is connected to a USB port on the PC via a USB cable. Portable computer or notebook PCs typically also have PC-memory card (earlier known as Personal Computer Memory card International Association; PCMCIA) slots that can receive PCMCIA memory cards configured as flash-memory card readers. In all, the many different memory card formats present a wide array of interface requirements not only for PCs but for other digital systems as well, such as embedded systems. Different adapters are needed for each of the memory card formats. One solution to consolidate the interfacing of flash-memory cards to desktop and portable computer PCs has been the design and manufacture of multi-format flash-memory card readers that are capable of reading the most popular formats. Such memory card-readers are sometimes referred to as ‘Seven-in-one’ readers indicating that they may be used with the currently popular flash-memory card formats. As indicated above, such multi-format card readers are typically designed with a USB interface. While USB devices, such as multi-format card readers and USB hubs designed with a USB interface, are typically connected to host PCs and/or notebook PCs via a USB cable, they may also be designed into computers as embedded USB devices. Typically, adding an embedded USB device, such as a card reader or hub, to a computer adversely affects power consumption of the computer. In general, a USB device attached to the USB host controller of the computer may prevent the central processing unit (CPU) of the computer from entering a low power state—e.g., the C3 state. The USB host controller, as a bus mastering peripheral, may keep the PCI bus active as long as it is attached to a USB device preventing the CPU from going into a low power state. This may especially be a problem for embedded devices (e.g., an embedded card reader). Unnecessary power may also be used to power a memory card that is not in use. When a memory card or multiple memory cards are inserted in a memory card-reader, they are normally fully powered as long as the memory card-reader is not in SUSPEND mode. In such case, the memory card can typically dissipate up to 100 mA, adversely affecting battery life. SUMMARY OF THE INVENTION In various embodiments, a USB device (e.g., a USB hub or card reader) coupled to a USB host controller may communicate with the USB host controller through an upstream port. In some embodiments, a USB hub may be coupled to a USB port to provide additional USB ports. Data may be transmitted from the USB device to the USB host controller and then used by a central processing unit (CPU). In some embodiments, if the USB device is turned off or is not in an active state (e.g., no cards are present in a USB card reader or no devices are attached to a USB hub), an algorithm (e.g., from the device's firmware) may be implemented to electrically disconnect the USB device from the USB host controller. In some embodiments, when the USB device is electrically disconnected from the USB host controller and no system activity from a bus mastering peripheral is occurring on the PCI bus, the CPU may enter a low power state (other system conditions may also need to be met). In various embodiments, a USB device, such as a card reader, may be embedded in a portable computer, such as a laptop. The card reader may read data from memory cards inserted into the card reader. If no memory cards are inserted in the card reader, an algorithm in the card reader's firmware may be implemented to electrically disconnect the card reader from a USB host controller. In some embodiments, when the card reader is electrically disconnected from the USB host controller and no system activity from a bus mastering peripheral is occurring on the PCI bus, the CPU may be allowed to enter a low power state (other conditions may also need to be met). In some embodiments, the card reader may be electrically disconnected or electrically reconnected from the USB host controller by a sideband signal from the computer to signal the card reader when to electrically disconnect and electrically reconnect. In some embodiments, if a card is inserted into the card reader, but has not been accessed for a first specified amount of time (e.g., 10 seconds), the card reader may power down the card. If the card is then accessed, the card reader may restore power to the card. In some embodiments, an algorithm in the card reader's firmware may power the card up and down. In some embodiments, a sideband signal may be sent to the card reader to signal the card reader to electrically disconnect after the card has been powered down. In some embodiments, the card may be powered down approximately at the same time that the card reader is electrically disconnected. In some embodiments, a sideband signal may be used to signal the card reader when to electrically reconnect. BRIEF DESCRIPTION OF THE DRAWINGS The foregoing, as well as other objects, features, and advantages of this invention may be more completely understood by reference to the following detailed description when read together with the accompanying drawings in which: FIG. 1 illustrates a portable computer for various embodiments; FIG. 2 is a block diagram of one embodiment of a computer, according to an embodiment; FIG. 3 illustrates a diagram of a card reader coupled to a USB host controller, according to an embodiment; FIG. 4 illustrates a diagram of a USB device coupled to a USB host controller, according to an embodiment; FIG. 5 illustrates a diagram of a hub with an attach detect logic and a physical interface, according to an embodiment; FIG. 6 illustrates a flowchart of a method for electrically disconnecting and electrically reconnecting a device from to a USB host controller, according to an embodiment; FIG. 7 illustrates a flowchart of a method for electrically disconnecting and electrically reconnecting a card reader to a USB host controller, according to an embodiment; FIG. 8 illustrates a flowchart of a method for electrically disconnecting and electrically reconnecting a hub to a USB host controller, according to an embodiment; FIG. 9 illustrates a flowchart of a method for regulating the CPU, according to an embodiment; and FIG. 10 illustrates a flowchart of a method for regulating a CPU while attached to a hub, according to an embodiment. While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. Note, the headings are for organizational purposes only and are not meant to be used to limit or interpret the description or claims. Furthermore, note that the word “may” is used throughout this application in a permissive sense (i.e., having the potential to, being able to), not a mandatory sense (i.e., must).” The term “include”, and derivations thereof, mean “including, but not limited to”. The term “coupled” means “directly or indirectly connected”. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates an embodiment of a portable computer 101 for various embodiments. Embodiments of the invention may be used with various different types of systems of computers, and portable computer 101 is one exemplary embodiment. In some embodiments, the portable computer 101 may be used with multiple peripheral devices such as, but not limited to, Universal Serial Bus (USB) devices (e.g., computer mouse 111, scanners, printers, external memory devices, cameras, personal digital assistants (PDAs), keyboards, touchscreens, and joysticks). Other peripheral devices are also contemplated. FIG. 2 is a block diagram of one embodiment of computer 101. In some embodiments, north bridge 205 (an integrated chip) couples the central processing unit (CPU) 203 and the system memory 201 to the peripheral component interconnect (PCI) bus 207 (used to connect peripherals to the computer). As shown, south bridge 209 couples to the PCI bus 207. In some embodiments, south bridge 209 may include a USB host controller 211 to communicate through a USB port 213 with a USB device 215. The USB port 213 and USB device 215 may be internal or external to the computer. In some embodiments, the USB host controller 211 may provide a peripheral bus interface between the USB device 215 and the computer. Referring again to FIG. 1, in some embodiments, USB devices, such as a card reader 113, may communicate with a computer (e.g., portable computer 101) through a USB host controller 211 in a PC chipset. The USB host controller 211 may regulate communication with attached USB devices (e.g., scheduling bandwidth on the bus). Communication speeds with the USB devices coupled to the USB host controller 211 may include low speed (LS), full speed (FS), and high speed (HS). In some embodiments, USB devices may be coupled to a computer (e.g., portable computer 101) through one or more USB ports 103. The USB ports 103 may be on the portable computer 101 or on a docking station (not shown) coupled to the portable computer 101. A USB connector 109 may plug into a USB port 103 to couple a USB device to the portable computer 101. In some embodiments, a hub (not shown) may be coupled to a USB port 103 of the portable computer 101 to provide additional USB ports. An internal hub may be used to provide multiple USB ports. For example, an internal hub may provide USB ports 103a, 103b, and 103c. In some embodiments, the hub may be internal to the portable computer 101, while, in some embodiments, the internal hub may be in a docking station for the portable computer 101. Other external hubs may be coupled to one of the USB ports 103 to provide additional USB ports for use. Multiple hubs may be chained together to provide even more USB ports. In some embodiments, the USB host controller 211 may detect USB devices as they are connected to a USB port 103, interrogate the USB device (e.g., to find out what speed to use for communication with the device and device capabilities), and load a driver to support the USB device. USB devices may communicate with the USB host controller 211 using control, interrupt, bulk, and isochronous transfers. In addition, the USB device may be powered over the USB bus, while some USB devices may be self powered. When a USB device is unplugged from a USB port 103, the USB host controller may detect the absence of the USB device and unload the driver. In some embodiments, a USB hub may not electrically connect to the USB host controller 211 until a device is coupled to the USB hub. In addition, some card readers 113 may not electrically connect to the USB host controller 211 until a card is inserted into the card reader 113. FIG. 3 illustrates an embodiment of a card reader 301 coupled to a USB host controller 211. In some embodiments, a card reader 301 may be embedded in a computer, such as a portable computer 101. The card reader 301 may communicate with a USB host controller 211 through an upstream port 305. The card reader 301 may use a controller 325 and a physical interface 303 to assist in reading, writing, and transferring data. The memory card 309 may be inserted into the card reader 301 through memory card slot 307. While the card reader 301 is shown with one card slot 307, a card reader 301 with multiple card slots may also be used. In some embodiments, the memory card may be a SmartMedia™ (SM) memory card, xD Picture Cards™ (xD), a Memory Stick™, a High Speed Memory Stick (HSMS), a Memory Stick PRO™ (MSPRO), a Secure Digital (SD) memory card, a MultiMediaMemory™ memory card (MMC), NAND Flash, Compact Flash™ (CF) or a CF form-factor Advanced Technology Attachment (ATA) hard drive. Other memory cards are also contemplated. In various embodiments, a cable between an upstream port 305 and a device (not shown) may carry a power line 321, ground 324, and a pair of data lines 322, 323 (D+ and D−) to transfer data between the card reader 301 and the computer. For full speed card readers, when the card reader 301 is attached to a USB port, the card reader 301 may pull the D+ line 322 high to approximately 3.3 volts using a pull up resistor (not shown) on the D+ line 322. The USB host controller may then detect the presence of the card reader 301 on the bus and reset the card reader 301. High speed devices connect the same way as full speed devices except, during reset, the device, such as a high speed card reader, “chirps” by driving the D− line 323 high. The USB host controller responds by alternately driving the D+ and D− lines high. When the high speed device detects the alternating chirps, the high speed device electrically removes the pull up resistor to balance the line and continues communicating at high speed. In some embodiments, the D+ and D− lines (322,323) may interact with the physical interface 303 through an attachment indicator mechanism 302. In some embodiments, if no memory card 309 is inserted in the card reader 301 (i.e., the card reader 301 is not in an active state) or the card reader 301 is turned off, an algorithm (e.g., stored in firmware on the card reader 301) may be implemented in the card reader 301 to electrically disconnect the card reader 301 from the USB host controller 211. Firmware may be on a read only memory (ROM) or a programmable read only memory (PROM) accessible by the card reader (e.g., internal or external memory). For example, firmware may be on an Electrically Erasable Programmable Read-Only Memory (EEPROM) that may be externally attached/detached to the card reader to activate/deactivate the electrical disconnect feature. For full speed devices to electrically disconnect, the pull up resistor may be electrically removed (i.e., set to a high impedance or “tri-stated”) from the D+ line. The USB host controller may interpret this as a disconnect. To electrically disconnect high speed devices, the D+ and D− lines may both be tri-stated (set to a high impedance). In some embodiments, when the card reader 301 is electrically disconnected from the USB host controller 211 and no system activity from a bus mastering peripheral is occurring on the PCI bus 207, the CPU 203 may enter a low power state. In some embodiments, if a memory card 309 is in the memory card slot 307, but has not been accessed in a first specified amount of time (e.g., 10 seconds), the memory card 309 may be powered down. In some embodiments, if a sideband signal is available, a sideband signal may be sent to signal the card reader 301 when to electrically disconnect and electrically reconnect. In one embodiment, if the card has not been accessed for a second specified amount of time (e.g., 10 minutes), the card reader 301 may be sent a sideband signal to electrically disconnect from the USB host controller 211. In some embodiments, the card reader 301 may not electrically disconnect from the USB host controller 211 with a memory card 309 inserted unless a sideband signal can be sent to the card reader 301 to signal it to electrically connect when needed. While an embodiment of a card reader 301 is shown in FIG. 3, it is to be understood that other embodiments may include other devices with removable medium. In addition, other devices coupled to the USB host controller 211 may also be electrically disconnected as seen in FIG. 4. FIG. 4 illustrates an embodiment of a USB device 401 coupled to a USB host controller 211. In some embodiments, a USB device 401 may be embedded in a computer, such as a portable computer 101. The USB device 401 may communicate with a USB host controller 211 through an upstream port 305. In some embodiments, the USB device 401 may have a controller 325 and a physical interface 303. Data may be transmitted from the USB device 401 to the USB host controller 211 and then used by a CPU 203. In some embodiments, if the USB device 401 is turned off or if the device 401 is not in an active state, an algorithm may be implemented to electrically disconnect the USB device 401 from the USB host controller 211. However, in some embodiments, the USB device 401 may not be electrically disconnected unless the USB device 401 has a way of being signaled to electrically reconnect to the USB host controller (e.g., by inserting a card into a card reader or attaching a device to a USB hub). In some embodiments, if a sideband signal can be used to signal the USB device 401 when to electrically disconnect and when to electrically reconnect, the USB device 401 may be signaled to electrically disconnect if the USB device 401 has not been used in a second specified amount of time (e.g., 10 minutes). A sideband signal may then be used to signal the USB device 401 to electrically reconnect. In some embodiments, when the USB device 401 is electrically disconnected from the USB host controller 211 and no system activity from a bus mastering peripheral is occurring on the PCI bus 207, the CPU 203 may enter a low power state. In some embodiments, a USB device 401 may be electrically disconnected through a physical interface on the USB device 401. For example, as described above, the physical interface 303 may tri-state (i.e., set to a high impedance) the D+ or the D+ and D− lines (i.e., the FS and HS transceivers) on the USB device 401 and remove any termination from the universal serial bus. FIG. 5 illustrates a diagram of an embodiment of a hub 501 with an attach detect logic 511 and a physical interface 303. In some embodiments, a hub 501 may be used to provide multiple downstream ports 513 for USB devices. For example, if hub 501 is internal to the portable computer 101, downstream ports 513 may be provided through USB ports 103 (see FIG. 1). The hub 501 may communicate through an upstream port 305 using a physical interface 303. In some embodiments, the upstream port 305 may be an external USB port (e.g., USB port 103), or, if the hub is internal to the portable computer 101, may be an internal connection to a USB host controller 211. In various embodiments, an attach detect logic 511 may be provided within the hub 501 to detect if a device is coupled to downstream ports 513. An auto detach logic 507 may be activated by a configuration bit loaded from an EEPROM 509. In some embodiments, the auto detach logic 507 may be activated by firmware internal to the hub 501. In some embodiments, if the attach detect logic 511 does not detect a device coupled to the downstream ports 513, a no ports signal 517 may be sent to the auto detach logic 507. The auto detach logic 507 may send a detach signal 515 to the physical interface 303 if the auto detach logic 507 has been configured by a configuration bit 519 from the EEPROM 509 and receives the no ports signal 517 from the attach detect logic 511. In some embodiments, if a device is not coupled to the hub 501, the hub 501 may be electrically disconnected after a wait period. If a device is coupled to the hub 501 during the wait period, the hub may not be electrically disconnected. In some embodiments, a sideband signal may be used to signal the hub 501 when to electrically disconnect and when to electrically reconnect. The hub 501 may be signaled by a sideband signal from the computer 101 to electrically disconnect if the hub 501 has not been used in a second specified amount of time (e.g., 10 minutes). A sideband signal may then be used to signal the hub 501 to electrically reconnect at a later time. In some embodiments, a sideband signal may be sent to the hub 501 when the computer goes into a SUSPEND mode to signal the hub 501 into a reduced functionality mode in which the hub 501 may only respond to a device trying to activate/wake the computer from SUSPEND mode (e.g., movement from a mouse coupled to the hub 501). The reduced functionality mode, and other modes signaled by the sideband signal, may result in lower power usage from the hub 501. FIG. 6 illustrates a flowchart of an embodiment of a method for electrically disconnecting a device from a USB host controller. It should be noted that in various embodiments of the methods described below, one or more of the steps described may be performed concurrently, in a different order than shown, or may be omitted entirely. Other additional steps may also be performed as desired. At 601, a determination is made whether a device is coupled to the USB host controller and in an active state. For example, a card in a card reader or a device attached to a USB hub may indicate the card reader and USB hub are in active states. At 603, if a device is not in an active state, the device may be electrically disconnected from the USB host controller. In some embodiments, if the device is not in an active state, the device may be electrically disconnected after a wait period in case the device becomes active again relatively quickly. If the device becomes active during the wait period (e.g., 2-3 seconds), the device may not be electrically disconnected. Other wait periods are also contemplated (e.g., 1-2 minutes, 10-20 minutes, etc.). In some embodiments, firmware may comprise algorithms to electrically disconnect the device if the device is not in an active state. However, in some embodiments, the USB device may not be electrically disconnected unless the USB device has a way of being signaled to electrically reconnect to the USB host controller (e.g., by a user inserting a card into a card reader, or receiving a sideband signal from the computer). At 605, if a device is in an active state, an electrical connection between the device and the USB host controller may be maintained. At 607, if the device enters an active state after the device is electrically disconnected, at 609, the device may be electrically reconnected to the host controller and flow may resume at 601. If the device is not in an active state, at 611, the device may be maintained in an electrically disconnected state and the flow may continue at 607. FIG. 7 illustrates a flowchart of an embodiment of a method for electrically disconnecting a card reader from a USB host controller. It should be noted that in various embodiments of the methods described below, one or more of the steps described may be performed concurrently, in a different order than shown, or may be omitted entirely. Other additional steps may also be performed as desired. At 701, a determination may be made whether a memory card is in the memory card slot of a card reader coupled to the USB host controller. In other embodiments, a determination may be made as to whether a removable storage medium is in a removable storage medium's reading device. At 703, if there is no memory card in the memory card slot, at 705, the card reader may be electrically disconnected from the USB host controller. In some embodiments, if the there is no memory card in the card reader, the card reader may be electrically disconnected after a wait period in case the user is switching out cards, etc. If a card is inserted during the wait period (e.g., 2-3 seconds), the card reader may not be electrically disconnected. Other wait periods are also contemplated. In some embodiments, to electrically disconnect the card reader, a physical interface for the card reader may tri-state both FS and HS transmitters on the card reader and remove any termination from the universal serial bus. For example, the D+ line (full speed devices) or the D+ line and the D− line (high speed devices) may be set to a high impedance. At 707, if there is a memory card in the memory card slot, a determination may be made whether the memory card has been accessed in a first specified amount of time. In some embodiments, the first specified amount of time may be approximately 10 seconds. Other first specified amounts of time are also contemplated. At 708, if the memory card has been accessed within the first specified amount of time, the card may remain powered up and flow may continue at 707. At 709, if the memory card has not been accessed within a first specified amount of time, the card may be powered down. At 715, if the host controller attempts to access the card, at 719, the card may be powered up and the flow may continue at 707. At 717, if the host controller is not attempting to access the card, the card may be maintained in a power down state and the flow may continue at 715. At 711, after the card reader has been electrically disconnected from the USB host controller, a determination may be made whether a card has been inserted into the card reader. At 712, if a card has not been inserted into the card reader, the card reader may be maintained in the electrically disconnected state, and flow may continue at 711. At 713, if a card has been inserted into the card reader, the card reader may be electrically reconnected and flow may continue at 707. FIG. 8 illustrates a flowchart of an embodiment of a method for electrically disconnecting a hub from a USB host controller. It should be noted that in various embodiments of the methods described below, one or more of the steps described may be performed concurrently, in a different order than shown, or may be omitted entirely. Other additional steps may also be performed as desired. At 801, a determination may be made whether a device is coupled to the hub. In some embodiments, an attach detect logic may be implemented to detect whether any devices are coupled to the hub. At 803, if a device is not coupled to the hub, at 805, the hub may be electrically disconnected from the USB host controller. In some embodiments, if a device is not coupled to the hub, the hub may be electrically disconnected after a wait period to give the user time to switch out devices, etc. If a device is coupled to the hub during the wait period, the hub may not be electrically disconnected. In some embodiments, an auto detach logic may be implemented to electrically disconnect the hub from the USB host controller. At 807, if a device is coupled to the hub, a connection may be maintained between the hub and the USB host controller and flow may continue at 803. At 809, if a device has been attached to the hub after the hub was electrically disconnected from the USB host controller, at 811, the hub may electrically reconnect to the host controller. At 813, if a device has not been attached to the hub, the hub may be maintained in an electrically disconnected state and the flow may continue at 809. FIG. 9 illustrates a flowchart of an embodiment of a method for regulating the CPU. It should be noted that in various embodiments of the methods described below, one or more of the steps described may be performed concurrently, in a different order than shown, or may be omitted entirely. Other additional steps may also be performed as desired. At 901, a determination may be made whether there are any USB devices connected to the USB host controller. At 903, if there is a device coupled to the USB host controller, a connection between the device and the USB host controller may be maintained, and at 905, the CPU may be maintained in an active state. At 907, if there are no devices coupled to the USB host controller, the USB host controller may not place a signal on the PCI bus. In some embodiments, if there is no activity on the PCI bus and other conditions for putting the CPU in a low power state are met, the CPU may go into a low power state. FIG. 10 illustrates a flowchart of an embodiment of a method for regulating a CPU while attached to a hub. It should be noted that in various embodiments of the methods described below, one or more of the steps described may be performed concurrently, in a different order than shown, or may be omitted entirely. Other additional steps may also be performed as desired. At 1001, a determination may be made whether any USB devices are coupled to the hub. At 1003, if there are USB devices coupled to the hub, a connection may be maintained between the hub and the USB host controller, and at 1005, the CPU may be maintained in the active state. At 1007, if there are no USB devices coupled to the hub, the hub may electrically disconnect from the USB host controller. At 1009, the USB host controller may not place a signal on the PCI bus. In some embodiments, if there is no activity on the PCI bus and other conditions for putting the CPU in a low power state are met, the CPU may go into a low power state. As used herein, a memory medium may include any of various types of memory devices or storage devices. The term “memory medium” is intended to include an installation medium, e.g., a CD-ROM, floppy disks 104, or tape device; a computer system memory or random access memory such as DRAM, DDR RAM, SRAM, EDO RAM, Rambus RAM, etc.; or a non-volatile memory such as a magnetic media, e.g., a hard drive, or optical storage. The memory medium may comprise other types of memory as well, or combinations thereof. In addition, the memory medium may be located in a first computer in which the programs are executed, or may be located in a second different computer which connects to the first computer over a network, such as the Internet. In the latter instance, the second computer may provide program instructions to the first computer for execution. The term “memory medium” may include two or more memory mediums which may reside in different locations, e.g., in different computers that are connected over a network. In addition, as used herein, a carrier medium—a memory medium as described above, as well as signals such as electrical, electromagnetic, or digital signals, conveyed via a communication medium such as a bus, network and/or a wireless link. The computer system 101 may include a memory medium(s) on which one or more computer programs or software components according to one embodiment of the present invention may be stored. For example, the memory medium may comprise a read only memory or programmable read only memory such as an EEPROM, or flash memory that stores a software program (e.g., firmware) that is executable to perform the methods described herein. Various embodiments further include receiving or storing instructions and/or data implemented in accordance with the foregoing description upon a carrier medium. Further modifications and alternative embodiments of various aspects of the invention may be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as the presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the spirit and scope of the invention as described in the following requests. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention This invention relates generally to the field of computer systems and, more particularly, to peripheral devices. 2. Description of the Related Art The Universal Serial Bus (USB) allows coupling of peripheral devices to a computer system. USB is a serial cable bus for data exchange between a host computer and a wide range of simultaneously accessible devices. The bus allows peripherals to be attached, configured, used, and detached while the host is in operation. For example, a card reader for reading flash memory cards may be coupled to a host computer through the USB. USB based systems may require that a USB host controller be present in the host system, and that the operating system (OS) of the host system support USB and USB Mass Storage Class Devices. A USB hub may be coupled to a USB host controller to allow multiple USB devices to be coupled to the host system through the USB host controller. In addition, other USB hubs may be coupled to the USB hub to provide additional USB device connections to the USB host controller. In recent years the electronics marketplace has seen a proliferation of appliances and personal electronics devices that use solid-state memory. For example, traditional film cameras have been losing market share to digital cameras capable of recording images that may be directly downloaded to and stored on personal computers (PCs). The pictures recorded by digital cameras can easily be converted to common graphics file formats such as Joint Photographic Experts Group (JPEG), Graphic Interchange Format (GIF) or Bitmap (BMP), and sent as e-mail attachments or posted on web pages and online photo albums. Many digital cameras are also capable of capturing short video clips in standard digital video formats, for example Moving Picture Experts Group (MPEG), which may also be directly downloaded and stored on personal computers (PCs) or notebook computers. Other devices that typically use solid-state memory include personal digital assistants (PDAs), pocket PCs, video game consoles and Moving Picture Experts Group Layer-3 Audio (MP3) players. The most widely used solid-state memory devices include flash-memory chips configured on a small removable memory card, and are commonly referred to as flash-memory cards. The majority of flash-memory cards currently on the market are typically one of: Compact Flash™, MultiMediaMemory™ memory card (MMC) and the related Secure Digital Memory card (SD), SmartMedia™ memory card (SM), xD Picture Cards™ (xD), and Memory Stick™. Most digital cameras, for example, use Compact Flash™ memory cards to record images. Many PDA models use Memory Stick™ memory cards to hold data. Some MP3 players store music files on SM memory cards. Generally, data saved by PDAs and other handheld devices using flash-memory cards are also transferred or downloaded to a PC. In the present application, the term “flash-memory” is intended to have the full breadth of its ordinary meaning, which generally encompasses various types of non-volatile solid-state memory devices as described above. Typically, a flash-memory card can easily be removed from the utilizing device. For example, a Compact Flash™ memory card can be removed from a digital camera much like film is removed from a standard camera. The flash-memory card can then be inserted into an appropriate flash-memory card reader coupled to a PC, and the image files directly copied to the PC. It should be noted that while a majority of smaller hand-held computers and PDAs have slots that receive Compact Flash™ memory cards, currently, most PCs do not, hence the need for a flash-memory card reader connecting to the PC. Most recently the preferred interface between flash-memory card readers and PCs has been the Universal Serial Bus, where the flash-memory card reader is connected to a USB port on the PC via a USB cable. Portable computer or notebook PCs typically also have PC-memory card (earlier known as Personal Computer Memory card International Association; PCMCIA) slots that can receive PCMCIA memory cards configured as flash-memory card readers. In all, the many different memory card formats present a wide array of interface requirements not only for PCs but for other digital systems as well, such as embedded systems. Different adapters are needed for each of the memory card formats. One solution to consolidate the interfacing of flash-memory cards to desktop and portable computer PCs has been the design and manufacture of multi-format flash-memory card readers that are capable of reading the most popular formats. Such memory card-readers are sometimes referred to as ‘Seven-in-one’ readers indicating that they may be used with the currently popular flash-memory card formats. As indicated above, such multi-format card readers are typically designed with a USB interface. While USB devices, such as multi-format card readers and USB hubs designed with a USB interface, are typically connected to host PCs and/or notebook PCs via a USB cable, they may also be designed into computers as embedded USB devices. Typically, adding an embedded USB device, such as a card reader or hub, to a computer adversely affects power consumption of the computer. In general, a USB device attached to the USB host controller of the computer may prevent the central processing unit (CPU) of the computer from entering a low power state—e.g., the C3 state. The USB host controller, as a bus mastering peripheral, may keep the PCI bus active as long as it is attached to a USB device preventing the CPU from going into a low power state. This may especially be a problem for embedded devices (e.g., an embedded card reader). Unnecessary power may also be used to power a memory card that is not in use. When a memory card or multiple memory cards are inserted in a memory card-reader, they are normally fully powered as long as the memory card-reader is not in SUSPEND mode. In such case, the memory card can typically dissipate up to 100 mA, adversely affecting battery life. | <SOH> SUMMARY OF THE INVENTION <EOH>In various embodiments, a USB device (e.g., a USB hub or card reader) coupled to a USB host controller may communicate with the USB host controller through an upstream port. In some embodiments, a USB hub may be coupled to a USB port to provide additional USB ports. Data may be transmitted from the USB device to the USB host controller and then used by a central processing unit (CPU). In some embodiments, if the USB device is turned off or is not in an active state (e.g., no cards are present in a USB card reader or no devices are attached to a USB hub), an algorithm (e.g., from the device's firmware) may be implemented to electrically disconnect the USB device from the USB host controller. In some embodiments, when the USB device is electrically disconnected from the USB host controller and no system activity from a bus mastering peripheral is occurring on the PCI bus, the CPU may enter a low power state (other system conditions may also need to be met). In various embodiments, a USB device, such as a card reader, may be embedded in a portable computer, such as a laptop. The card reader may read data from memory cards inserted into the card reader. If no memory cards are inserted in the card reader, an algorithm in the card reader's firmware may be implemented to electrically disconnect the card reader from a USB host controller. In some embodiments, when the card reader is electrically disconnected from the USB host controller and no system activity from a bus mastering peripheral is occurring on the PCI bus, the CPU may be allowed to enter a low power state (other conditions may also need to be met). In some embodiments, the card reader may be electrically disconnected or electrically reconnected from the USB host controller by a sideband signal from the computer to signal the card reader when to electrically disconnect and electrically reconnect. In some embodiments, if a card is inserted into the card reader, but has not been accessed for a first specified amount of time (e.g., 10 seconds), the card reader may power down the card. If the card is then accessed, the card reader may restore power to the card. In some embodiments, an algorithm in the card reader's firmware may power the card up and down. In some embodiments, a sideband signal may be sent to the card reader to signal the card reader to electrically disconnect after the card has been powered down. In some embodiments, the card may be powered down approximately at the same time that the card reader is electrically disconnected. In some embodiments, a sideband signal may be used to signal the card reader when to electrically reconnect. | 20040120 | 20070109 | 20050721 | 78811.0 | 6 | LEE, SEUNG H | PERIPHERAL DEVICE FEATURE ALLOWING PROCESSORS TO ENTER A LOW POWER STATE | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,762,887 | ACCEPTED | Cardiac monitoring | Systems and techniques for monitoring cardiac activity. In one aspect, a method includes collecting information describing the variability in heart rate over a series of beats, designating variability at a lower end of physiological values as being largely irrelevant to atrial fibrillation, designating variability in a midrange of physiological values as being indicative of atrial fibrillation, designating variability in an upper range of physiological values as being negatively indicative of atrial fibrillation, and determining a relevance of the variability described in the collection to atrial fibrillation. | 1. A method comprising: determining a beat-to-beat variability in cardiac electrical activity; determining a relevance of the variability to one of atrial fibrillation and atrial flutter using a non-linear statistics; identifying one of an atrial fibrillation event and an atrial flutter event based on the determined relevance, the event being a period in time when the information content of the cardiac electrical activity is of increased relevance. 2. The method of claim 1, further comprising identifying the end of the event based on the determined relevance. 3. The method of claim 1, further comprising transitioning into an event state associated with atrial fibrillation in response to identification of the event. 4. The method of claim 1, further comprising transmitting the event to a remote receiver from an ambulatory patient. 5. The method of claim 1, wherein determining the relevance of the variability to atrial fibrillation comprises: receiving information identifying a ventricular beat; and assigning a preset value indicating that the variability is negatively indicative of atrial fibrillation. 6. The method of claim 5, further comprising identifying a ventricular tachycardia event based at least in part on the information identifying the ventricular beat. 7. The method of claim 1, wherein determining the relevance of the variability to atrial fibrillation comprises determining an average relevance of variability in a collection of R to R intervals. 8. The method of claim 1, wherein determining the beat-to-beat variability comprises determining the beat-to-beat variability in a series of successive beats. 9. The method of claim 8, wherein determining the beat-to-beat variability in a series of successive beats comprises determining the variability in an interval between successive R-waves. 10. The method of claim 1, wherein identifying the event comprises comparing the relevance of the variability to a first predetermined amount of relevance. 11. The method of claim 10, further comprising comparing the relevance of the variability in the event to a second predetermined amount of relevance to identify the end of the event, the second predetermined amount being lower than the first predetermined amount. 12. A method comprising: collecting information describing the variability in heart rate over a series of beats; designating variability at a lower end of physiological values as being largely irrelevant to atrial fibrillation; designating variability in a midrange of physiological values as being indicative of atrial fibrillation; designating variability in an upper range of physiological values as being negatively indicative of atrial fibrillation; and determining a relevance of the variability described in the collection to atrial fibrillation. 13. The method of claim 12, wherein designating the variability comprises multiplying the information describing the variability by a weighting factor. 14. The method of claim 12, wherein collecting the information comprises collecting information describing a variability in R to R intervals over a series of beats. 15. The method of claim 14, wherein collecting the information describing the variability comprises collecting information that is a function of a ratio of a first R to R interval and an immediately preceding R to R interval. 16. The method of claim 15, wherein collecting the information describing the variability comprises collecting information related to factor DRR(n) as given by DRR ( n ) = ABS ( RR ( n , n - 1 ) RR ( n , n - 1 ) + RR ( n - 1 , n - 2 ) - 1 2 ) . 17. The method of claim 16, wherein designating the variability at the lower end of physiological values as being largely irrelevant comprises designating information related to factors DRR(n) less than about 0.0.2 as being largely irrelevant. 18. The method of claim 16, wherein designating the variability at the midrange of physiological values as being indicative of atrial fibrillation comprises designating information related to factors DRR(n) greater than about 0.02 and less than about 0.15 as being indicative of atrial fibrillation. 19. The method of claim 16, wherein designating the variability at the upper range of physiological values as being negatively indicative of atrial fibrillation comprises designating information related to factors DRR(n) greater than about 0.157 as being negatively indicative of atrial fibrillation. 20. The method of claim 12, wherein collecting the information describing the variability comprises collecting the variability in heart rate over a series of between 20 and 200 of the recent R to R intervals. 21. The method of claim 12, wherein determining the relevance of the variability comprises determining the relevance of the variability to sustained atrial fibrillation. 22. The method of claim 12, wherein the series of R to R intervals is a continuous series of R to R intervals. 23. A method comprising: comparing recent R to R intervals with preceding R to R intervals to yield a collection of comparisons; weighting the comparisons according to a likelihood that the comparisons are relevant to atrial fibrillation, the weighting including identifying a first of the recent beats as a ventricular beat, and assigning a preset value to weight the first beat in the collection, the preset value being negatively indicative of atrial fibrillation; and determining the average relevance of the collection to atrial fibrillation. 24. The method of claim 23, wherein weighting the comparisons comprises: designating variability at a lower end of physiological values as being largely irrelevant to atrial fibrillation; and designating variability in a midrange of physiological values as being indicative of atrial fibrillation. 25. The method of claim 23, wherein weighting the comparisons comprises designating variability in an upper range of physiological values as being negatively indicative of atrial fibrillation. 26. The method of claim 23, further comprising identifying a ventricular tachycardia event based at least in part on the identification of the ventricular beat. 27. The method of claim 23, wherein comparing comprises comparing recent R to R intervals with immediately preceding R to R intervals to yield a collection of comparisons. | BACKGROUND The following description relates to cardiac monitoring, for example, by monitoring cardiac electrical activity. The electrical activity of the heart can be monitored to track various aspects of the functioning of the heart. Given the volume conductivity of the body, electrodes on the body surface or beneath the skin often display potential differences related to this activity. Anomalous electrical activity can be indicative of disease states or other physiological conditions that can range from benign to deadly. One example of such a physiological condition is atrial fibrillation. Atrial fibrillation involves the loss of synchrony between the atria and the ventricles. In complex atrial fibrillation, long-lived wavelets of depolarization travel along circular paths in the atria. This can lead to irregular ventricular beating as well as blood stagnation and clotting in the atria. Atrial fibrillation is among the most common forms of cardiac arrhythmia and may affect more than two million people annually. Atrial fibrillation has been associated with stroke, congestive heart failure, and cardiomyopathy. Another example of such a physiological condition is atrial flutter. Atrial flutter also involves the loss of synchrony between the atria and the ventricles. In atrial flutter, multiple atrial waveforms reach the atrioventricular (AV) node during each ventricular beat due to, e.g., atrial scars, an atrial infarction, or a re-entrant circuit encircling a portion of the right atrium. Atrial flutter is less common than atrial fibrillation but is also associated with stroke, congestive heart failure, and cardiomyopathy. SUMMARY The cardiac monitoring systems and techniques described here may include various combinations of the following features. A method can include determining a beat-to-beat variability in cardiac electrical activity, determining a relevance of the variability to one of atrial fibrillation and atrial flutter using a non-linear statistics, identifying one of an atrial fibrillation event and an atrial flutter event based on the determined relevance. The event is a period in time when the information content of the cardiac electrical activity is of increased relevance. The end of the event can be identified based on the determined relevance. An event state associated with atrial fibrillation can be transitioned into in response to identification of the event. The event can be transmitted to a remote receiver from an ambulatory patient. The relevance of the variability to atrial fibrillation can be determined by receiving information identifying a ventricular beat and assigning a preset value indicating that the variability is negatively indicative of atrial fibrillation. A ventricular tachycardia event can be identified based at least in part on the information identifying the ventricular beat. The relevance of the variability to atrial fibrillation can be determined by determining an average relevance of variability in a collection of R to R intervals. The beat-to-beat variability can be determined in a series of successive beats, e.g., by determining the variability in an interval between successive R-waves. The event can be identified by comparing the relevance of the variability to a first predetermined amount of relevance. Further, the relevance of the variability in the event can be compared to a second predetermined amount of relevance to identify the end of the event. The second predetermined amount can be lower than the first predetermined amount. A method can include collecting information describing the variability in heart rate over a series of beats, designating variability at a lower end of physiological values as being largely irrelevant to atrial fibrillation, designating variability in a midrange of physiological values as being indicative of atrial fibrillation, designating variability in an upper range of physiological values as being negatively indicative of atrial fibrillation, and determining a relevance of the variability described in the collection to atrial fibrillation. The variability can be designated by multiplying the information describing the variability by a weighting factor. Information describing a variability in R to R intervals over a series of beats can be collected. The collected information can be a function of a ratio of a first R to R interval and an immediately preceding R to R interval, such as information related to factor DRR(n) as given by DRR ( n ) = ABS ( RR ( n , n - 1 ) RR ( n , n - 1 ) + RR ( n - 1 , n - 2 ) - 1 2 ) . The variability at the lower end of physiological values can be designated as being largely irrelevant by designating information related to factors DRR(n) less than about 0.0.2 as being largely irrelevant. The variability at the midrange of physiological values can be designated as being indicative of atrial fibrillation by designating information related to factors DRR(n) greater than about 0.02 and less than about 0.15 as being indicative of atrial fibrillation. The variability at the upper range of physiological values can be designated as being negatively indicative of atrial fibrillation by designating information related to factors DRR(n) greater than about 0.157 as being negatively indicative of atrial fibrillation. Information describing the variability can be collected by collecting the variability in heart rate over a series of between 20 and 200 of the recent R to R intervals. The determined relevance of the variability can be the relevance of the variability to sustained atrial fibrillation. The series of R to R intervals can be a continuous series of R to R intervals. A method can include comparing recent R to R intervals with preceding R to R intervals to yield a collection of comparisons, weighting the comparisons according to a likelihood that the comparisons are relevant to atrial fibrillation, and determining the average relevance of the collection to atrial fibrillation. The weighting can include identifying a first of the recent beats as a ventricular beat and assigning a preset value to weight the first beat in the collection. The preset value can be negatively indicative of atrial fibrillation. The comparisons can be weighted by designating variability at a lower end of physiological values as being largely irrelevant to atrial fibrillation and designating variability in a midrange of physiological values as being indicative of atrial fibrillation. The comparisons can also be weighted by designating variability in an upper range of physiological values as being negatively indicative of atrial fibrillation. A ventricular tachycardia event can be identified based at least in part on the identification of the ventricular beat. Recent R to R intervals can be compared with immediately preceding R to R intervals to yield a collection of comparisons. The cardiac monitoring systems and techniques may provide one or more of the following advantages. Atrial fibrillation (“AFib”) and/or atrial flutter (“AFlut,” with “AF” referring to either) can be distinguished from other types of cardiac arrhythmia, such as the normal sinus rhythm irregularity, irregularity from various types of heart blocks, and the irregularity associated with premature ventricular contractions. The described systems and techniques are a practical approach to calculating the beat-to-beat irregularity while providing improved positive predictability of AF. Moreover, the described systems and techniques are able to identify sustained AF episodes, where AF continues for more that approximately 20 beats and has an increased clinical significance. For example, when the systems and techniques described here were used to analyze the MIT-BIH arrhythmia database, available from MIT-BIH Database Distribution, MIT Room E25-505A, Cambridge, Mass. 02139, USA, a sensitivity to AF in excess of 90% and a positive predictivity in excess of 96% were obtained. The described systems and techniques are well-adapted to monitoring cardiac signals of ambulatory patients who are away from controlled environments such as hospital beds or treatment facilities. The cardiac signals obtained from to ambulatory patients may be noisier and otherwise strongly impacted by the patients' heightened levels of activity. Thus, improved monitoring systems and techniques, such as those described herein, are required for ambulatory patients. The described systems and techniques are also well-adapted to real-time monitoring of arrhythmia patients, where minimal delays in distinguishing between different types of cardiac arrhythmia can speed the delivery of any urgent medical care. The described systems and techniques also require minimal computational resources. Further, the described systems and techniques do not require training before different types of cardiac arrhythmia can be distinguished. The details of one or more implementations of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. DESCRIPTION OF DRAWINGS FIG. 1 shows a system in which a cardiac signal is monitored for medical purposes. FIG. 2 shows an example of a cardiac signal. FIG. 3 shows an example of instrumentation for cardiac monitoring using a cardiac signal. FIG. 4 shows an example state diagram of a cardiac monitoring system during cardiac monitoring. FIG. 5 shows a process for cardiac monitoring for the detection of an AF event. FIG. 6 shows a process for determining the variability in the recent R to R intervals and identifying if the variability is relevant to either the onset or termination of AF. FIG. 6B shows a graph of factor DRR(n) as a function of RR(n−1,n−2)/RR(n,n−1). FIG. 7 shows a transformation function for weighting the variability in the timing of recent beats. FIG. 8 shows an example of instrumentation for cardiac monitoring using an electrocardiogram trace. FIG. 9 shows an example state diagram of a cardiac monitoring system that accommodates the variability caused by ventricular beats. FIG. 10 shows a process for determining the variability of recent R to R intervals and identifying if the variability is relevant to the onset of AF while accommodating the variability caused by ventricular beats. FIG. 11 shows a process for determining the variability in recent R to R intervals and identifying if the variability is relevant to the termination of AF while accommodating the variability caused by ventricular beats. Like reference symbols in the various drawings indicate like elements. DETAILED DESCRIPTION FIG. 1 shows a system 100 in which a cardiac signal is monitored for medical purposes. System 100 includes an individual 105, instrumentation 110, a signal path 115, and a receiver 120. Individual 105 can be a patient or a healthy individual for whom monitoring of one or more biological signals is deemed to be appropriate. Instrumentation 110 can include one or more sensing, calibration, signal processing, control, data storage, and transmission elements suitable for generating and processing the cardiac signal, as well as relaying all or a portion of the cardiac signal over path 115. Path 115 can be any suitable medium for data transmission, including wired and wireless media suitable for carrying optical and/or electrical signals. The receiver 120 can include a receiver element for receiving the transmitted signal, as well as various data processing and storage elements for extracting and storing the information carried by the transmission regarding the state of individual 105. The receiver 120 can be a medical system in that receiver 120 presents information to medical personnel or to a medical expert system for analysis. The receiver 120 either can reside remotely from instrumentation 110 in that receiver 120 is not located at the same site as instrumentation 110 (e.g., at the same hospital, nursing home, or other medical care facility) or the receiver 120 can reside within the same general area or vicinity as instrumentation 110 (e.g., within the same room, building, or health care facility). FIG. 2 shows an example of a cardiac signal, namely the trace of a scalar electrocardiogram 200. Electrocardiogram trace 200 follows a potential difference 205 measured between two points on the body surface of an individual. Potential difference 205 changes with time 210 in a manner characteristic of the physiology and function of an individual's heart. Electrocardiogram trace 200 generally includes features characteristic with particular aspects of cardiac activity. For example, trace 200 includes a series of QRS complexes 215, 220, 225 associated with activation of the ventricles. QRS complex 225 includes an R-wave Rn, QRS complex 220 includes an R-wave Rn−1, and QRS complex 215 includes an R-wave Rn−2. The time between successive R-waves can be referred to as the R to R interval. In particular, the R to R interval between R-wave Rn and R-wave Rn−1 is RR(n,n−1) and the R to R interval between R-wave Rn−1 and R-wave Rn−2 is RR(n−1,n−2). FIG. 3 shows an example of instrumentation 110 for cardiac monitoring using a cardiac signal such as electrocardiogram trace 200. Instrumentation 110 includes a sensor 305, a signal amplifier/processor 310, a beat detector 315, an atrial fibrillation/atrial flutter (AF) detector 320, decision logic 325, and an event generator 330. Sensor 305 can include two or more electrodes subject to one or more potential differences that yield a voltage signal such as electrocardiogram trace 200. The electrodes can be body surface electrodes such as silver/silver chloride electrodes and can be positioned at defined locations to aid in monitoring the electrical activity of the heart. Sensor 305 can also include leads or other conductors that form a signal path to signal amplifier/processor 310. Signal amplifier/processor 310 can receive, amplify, and/or process the voltage signals. The processing can include filtering and digitization. The amplification and remainder of the processing can occur before or after digitization. Signal amplifier/processor 310 can provide the amplified and/or processed signal to beat detector 315. Beat detector 315 is a device such as a circuit or other arrangement that identifies the time period between ventricular contractions. For example, beat detector 315 can be a QRS detector in that it identifies successive QRS complexes (or an equivalent indicator of ventricular activity) and determines the beat-to-beat timing from the time between complexes. The beat-to-beat timing can be determined by measuring times between successive R-waves, such as RR(n,n−1) and RR(n−1,n−2) in electrocardiogram trace 200 (FIG. 2). Beat detector 315 can provide information regarding the time period between ventricular contractions to AF detector 320. AF detector 320 is a data processing device that analyzes information regarding the time period between ventricular contractions to detect AF. The detection of AF can include distinguishing AF from other sources of ventricular irregularity, such as premature ventricular contraction, heart blocks, and normal sinus rhythm irregularity. The detection of AF can also include distinguishing between short AF episodes and sustained AF episodes. Short AF episodes generally include between two and 20 beats and may or may not have clinical significant, whereas sustained AF episodes generally include more than 20 beats and may have relatively greater clinical significance. The detection of AF can also include the detection of other types of irregularity caused by random refractory periods of the ventricles. AF detector 320 can analyze information regarding the time period between ventricular contractions to detect AF using non-linear statistical approaches. Non-linear statistics treats the relationship between variables as something other than a linear function. Detail regarding an example non-linear statistical approach to detecting AF is given below. AF detector 320 can provide information regarding the detection of AF to decision logic 325. Decision logic 325 is a set of instructions for determining when the AF detected by AF detector 320 has commenced and terminated. For example, decision logic 325 can be embodied in a circuit or decision logic 325 can be executed by a data processing device such as AF detector 320. Decision logic 325 can also trigger the generation of an AF event by event generator 230. Event generator 330 is a device such as a data processing device that prepares an AF event for handling. An AF event is a period in time when the information content of the signal sensed by sensor 305 is deemed to be of increased relevance to the monitoring of AF. AF events need not be of equal or predetermined duration. For example, an event associated with an sustained AF episode may have a longer duration than an event associated with a short AF episode. Event generator 330 can prepare an AF event for handling by collecting information that summarizes the relevance of the event to the detection and/or monitoring of AF. For example, event generator 330 can excise data associated with the period identified as AF from the amplified and processed signal output from signal amplifier/processor 310. Event generator 330 can also redact such data (e.g., by selecting the first three minutes worth when generating the event). Handling the AF event can include transmitting the AF event over data link 115 or storing the AF event in a data storage device. FIG. 4 shows an example state diagram 400 of a cardiac monitoring system during cardiac monitoring. For example, state diagram 400 can relate to the operation of an assembly such as AF detector 320 and decision logic 325 in instrumentation 110 (FIG. 3). State diagram 400 includes an idle state 405 and an AF event state 410. Idle state 405 originates a reflexive transition 415 and a state transition 420. AF event state 410 originates a reflexive transition 425 and a state transition 430. Reflexive transition 415 is associated with a series of variability measurements. State transition 420 is triggered by the onset of AF-type variability as detected by such measurements. Reflexive transition 425 is associated with another series of variability measurements. State transition 430 is triggered by the end of AF-type variability as detected by such measurements. In operation, a cardiac monitoring system can start in idle state 405 and measure the variability of a cardiac signal. For example, the system can measure the variability in the beat-to-beat timing of successive R-waves, such as the variability between RR(n,n−1) and RR(n−1,n−2) in electrocardiogram trace 200 (FIG. 2). Once the variability has been identified as AF-type variability, the system transitions to AF event state 410 where the system continues to measure the variability of the cardiac signal. In AF event state 410, once the AF-type variability has ended, the system returns to idle state 405. FIG. 5 shows a process 500 for cardiac monitoring, e.g., for the detection of an AF event. Process 500 can be performed by one or more data processing devices that perform data processing activities. The activities of process 500 can be performed in accordance with the logic of a set of machine-readable instructions, a hardware assembly, or a combination of these and/or other instructions. The activities in process 500 can be performed at any of a number of different elements in a system in which a biological signal is monitored. For example, in instrumentation 110 (FIG. 3), the activities in process 900 can be performed at AF detector 320, decision logic 325, and event generator 330. The device performing process 500 receives information regarding the timing of recent beats at 505. The timing information can be received in discrete amounts (e.g., on a beat-to-beat basis) or in a collection that includes such information. Using the received timing information, the system determines the variability in the recent R to R intervals at 510. The variability in the R to R intervals can reflect the beat-to-beat change in heart rate over a set period or over a set number of beats. The system can also identify the relevance of such variability to AF at 515. The variability is relevant to AF when it is associated with a high probability that an individual undergoes AF at or near the time of the recent beats. Relevance can be identified by comparing the variability to a predetermined amount of variability or to an amount identified as typical for the monitored patient. The system can also determine if the identified relevance of the variability is indicative of the monitored individual undergoing AF at decision 520. If not, the system returns to 505. This return can correspond to the system remaining in idle state 405 along reflexive transition 415 in state diagram 400 (FIG. 4). If the system determines that the results of the monitoring are indicative of the individual undergoing AF, the system initiates an AF event at 525. This initiation of the AF event can correspond to the system transitioning to AF event state 410 in state diagram 400 (FIG. 4). The initiation of such an event can include various activities that lead to the generation of an event, such as triggering an event generator to add markers to a data stream such as electrocardiogram trace 200 or excising a relevant portion of the data stream. The system can continue to receive information regarding the timing of recent beats at 530. Using the received timing information, the system determines the variability in the recent R to R intervals at 535. The system can also identify the relevance of such variability to the end of AF at 540. The variability is relevant to the end of AF when it is associated with an increased probability that AF has halted. Relevance can be identified by comparing the variability to a predetermined amount of variability or to an amount identified as typical for the monitored patient. The system can also determine if the identified relevance of the variability indicates that AF has ended in the monitored individual at decision 545. If not, the system returns to 530. This return can correspond to the system remaining in AF event state 410 along reflexive transition 425 in state diagram 400 (FIG. 4). If the system determines that AF has ended in the monitored individual, the system returns to 555. This return can correspond to the system transitioning to idle state 405 in state diagram 400 (FIG. 4). FIG. 6A shows a process 600 for determining the variability in the recent R to R intervals and identifying if the variability is relevant to either the onset or termination of AF. Process 600 can be performed independently or process 600 can be performed as part of a larger collection of activities. For example, process 600 can be performed as part of process 500, namely as steps 510, 515 or as steps 535, 540 (FIG. 5). Various activities in process 600 can also be performed to trigger state transitions 420, 430 in state diagram 400 (FIG. 4). The system performing process 600 can compare the most recent R to R interval (e.g., RR(n,n−1) of FIG. 2) with the immediately preceding R to R interval (e.g., RR(n−1,n−2) of FIG. 2) at 605. Such a comparison can yield a factor that reflects the beat-to-beat variability in heart rate. For example, a factor DRR(n), given by the expression DRR ( n ) = ABS ( RR ( n , n - 1 ) RR ( n , n - 1 ) + RR ( n - 1 , n - 2 ) - 1 2 ) Equation 1 can reflect the beat-to-beat variability in R to R interval and in heart rate. A graph of factor DRR(n) as a function of RR(n−1,n−2)/RR(n,n−1) is shown in FIG. 6B. The system performing process 600 can also weight the comparison of the most recent R to R interval with the immediately preceding R to R interval according to the likelihood that the results of the comparison are indicative of AT at 610. The weighting can determine a role that the comparison will play in subsequent processing cardiac monitoring activities. For example, the weighting can include the whole or partial exclusion of a certain comparisons from subsequent cardiac monitoring activities. One technique for weighting the comparison is through the use of a transformation, such as transformation function 700 shown in FIG. 7. Transformation function 700 provides weights that are multiplied by the value of a comparison (e.g., factor DRR(n)) to reflect the relevance of the comparison to AF. The weights provided in transformation function 700 can be multiplied by the value of every comparison or by a selected subset of the comparisons. One technique for selecting such a subset is discussed further below. Transformation function 700 is adapted to the factor DRR(n) given in equation 1. In particular, transformation function 700 is adapted to overweight factor DRR(n) when factor DRR(n) is in a midrange of potential physiological values (e.g., when DRR(n) is greater than about 0.02 and less than about 0.15). Transformation function 700 is adapted to weight factor DRR(n) as being negatively indicative of AF when factor DRR(n) is at the upper range of potential physiological values (e.g., when DRR(n) is greater than about 0.157). Transformation function 700 is adapted to weight factor DRR(n) as being largely irrelevant to AF when factor DRR(n) is at the lower range of potential physiological values (e.g., when DRR(n) is less than about 0.0.2). Transformation function 700 includes a scalar weight 705 that varies as a function of the comparison factor DRR(n) 710. In particular, weight 705 varies linearly between points 715, 720, 725, 730, 735. The values of points 715, 720, 725, 730, 735 are given in Table 1. TABLE 1 Comparison Point DRR(n) Weight 715 0 0 720 0.0206 0.0417 725 0.0642 0.9178 730 0.1427 0.1005 735 0.2 −0.3 In operation, weight 705 for any value of the factor DRR(n) can be determined by linear interpolation between the weights of points 715, 720, 725, 730, 735. The interpolation can be performed for each value of the factor DRR(n) as it arises or the results of a certain number of such interpolations can be stored in a look up table. For any value of the factor DRR(n) above 0.2, a weight of −0.3 can be assigned. Returning to FIG. 6A, the system performing process 600 can also add a weighted comparison to a collection of weighted comparisons for recent beats at 615. For example, the system can form a FIFO stack or an array of weighted comparisons having a separate data element for each of between 10 and 200 (e.g., 100) of the most recent beats. The system can also determine the relevance of the collection of weighted comparisons for recent beats to AF at 620. The collection of weighted comparisons can be relevant to either the onset or termination of AF. To determine the relevance, the system can sum the weighted comparisons to arrive at a number that represents the average relevance of the weighted comparisons in the collection. The system can calculate such sums for several beats in a row before determining that the beat-to-beat variability is indicative of the onset or termination of AF. In one implementation, the system calculates the average of the weighted comparisons of the beats in the collection and compares this average with a first predetermined threshold to determine if the variability is indicative of the onset of AF and with a second predetermined threshold to determine if the variability is indicative of the termination of AF. In general, the first, onset threshold may be higher than the second, termination threshold. The difference between the onset and termination thresholds can introduce hysteresis into the state transitions to stabilize any system performing process 600. FIG. 8 shows an example of instrumentation for cardiac monitoring using an electrocardiogram trace, namely instrumentation 800. In addition to sensor 305, signal amplifier/processor 310, AF (AF) detector 320, decision logic 325, and event generator 330, instrumentation 800 also includes a QRS detector 805 and a ventricular beat detector 810. QRS detector 805 and ventricular beat detector 810 can both receive an amplified and processed signal from signal amplifier/processor 310. QRS detector 805 is a device such as a circuit or other arrangement that identifies the time period between successive QRS complexes. QRS detector 805 can provide information regarding the time period between successive QRS complexes to AF detector 320. Ventricular beat detector 810 is a device such as a circuit or other arrangement that identifies ventricular beats. Ventricular beats (i.e., premature ventricular beats) are irregular beats that interrupt the normal heart rhythm. Ventricular beats generally arise from a ventricular focus with enhanced automaticity. Ventricular beats may also result from reentry within the His-Purkinje system. The occurrence of ventricular beats is generally unrelated to AF. For example, the occurrence of ventricular beats can be used to identify ventricular tachycardia (e.g., when there are three or more consecutive ventricular beats). Ventricular beats may be precipitated by factors such as alcohol, tobacco, caffeine, and stress. Ventricular beat detector 810 can monitor an electrocardiogram trace to identify ventricular beats. Various systems and techniques for identifying ventricular beats can be used. For example, the Mortara VERITAS Analysis Algorithm, available from Mortara Instrument, Inc. (Milwaukee, Wis.), can be used. Ventricular beat detector 810 can also provide information regarding the occurrence of ventricular beats to AF detector 320. Ventricular beat detector 810 can be housed together with QRS detector 805. An example of such a joint device is the ELI 250TM Electrocardiograph available from Mortara Instrument, Inc. (Milwaukee, Wis.). Approaches for determining the variability in recent R to R intervals and identifying if the variability is relevant to either the onset or termination of AF can accommodate the variability caused by ventricular beats. FIG. 9 shows an example state diagram 900 of a cardiac monitoring system that accommodates the variability caused by ventricular beats. In addition to idle state 405 and AF event state 410, state diagram 900 also includes a ventricular tachycardia (V-TACH) event state 905. Ventricular tachycardia is a rapid succession of ventricular contractions (e.g., between 140 and 220 per minute) generally caused by an abnormal focus of electrical activity in a ventricle. Ventricular tachycardia can last from a few seconds to several days and can be caused by serious heart conditions such as a myocardial infarction. AF event state 410 originates a state transition 910 that is triggered by the occurrence of three consecutive ventricular beats. V-TACH event state 905 originates a state transition 910 that is triggered by the end of a V-TACH event. The end of a V-TACH event can be identified, e.g., when the rate of ventricular contractions falls below a predetermined value (e.g., a value between 100 and 200 bpm). FIG. 10 shows a process for determining the variability in recent R to R intervals and identifying if the variability is relevant to the onset of AF while accommodating the variability caused by ventricular beats, namely a process 1000. Process 900 can be performed independently or process 1000 can be performed as part of a larger collection of activities. For example, process 1000 can be performed as part of process 500, namely as steps 510, 515 (FIG. 5). Various activities in process 1000 can also be performed to trigger state transition 420 in state diagram 900 (FIG. 9). The system performing process 1000 can compare the recent R to R intervals with the respective, immediately-preceding R to R intervals at 1005 using, e.g., the expression in Equation 1 to reflect the beat-to-beat variability in heart rate. The system performing can also receive an indicator of the occurrence of a ventricular beat at 1010. Such an indicator can be received, e.g., from a ventricular beat detector. The system can create an array or other data structure that includes both the ventricular beat indicators and the R to R interval comparisons at 1015. The array can include the ventricular beat indicators and the R to R interval comparisons for between 10 and 200 (e.g., 100) of the most recent beats. The system can also weight the comparisons according to the likelihood that the R to R interval comparisons are relevant to AF at 1020 using, e.g., transformation function 700 (FIG. 7). The system can also assign a preset value to the R to R interval comparisons associated with ventricular beats at 1025. The preset value can be a penalty value in that the preset value reflects a decreased likelihood that the variability is indicative of an AF event. The preset value can be selected in light of the approaches used to compare the R to R intervals and to weight such comparisons. For example, when the R to R intervals are compared using Equation 1 and the resulting comparisons are weighted using transformation function 700 (FIG. 7), R to R interval comparisons associated with ventricular beats can be assigned a preset value of −0.06 and R to R intervals comparisons associated with the R to R intervals immediately succeeding ventricular beats can be assigned a preset value of zero. Using both the weighted and preset timing comparisons, the system can calculate the average value of an entry in the array of the most recent beats at 1030. If the system determines that the average is greater than 0.22 for the last five beats at decision 1035, then the system triggers the start of an AF event in the recent beats at 1040. On the other hand, if the system determines that the average is less than or equal to 0.22 for the last five beats, then the system returns to compare the recent R to R intervals with the previous R to R interval at 1005. FIG. 11 shows a process for determining the variability in the recent R to R intervals and identifying if the variability is relevant to the termination of AF while accommodating the variability caused by ventricular beats, namely a process 1100. Process 1100 can be performed independently or process 1100 can be performed as part of a larger collection of activities. For example, process 1100 can be performed as part of process 500, namely as steps 535, 540 (FIG. 5). Various activities in process 1100 can also be performed to trigger state transitions 430, 910, 915 in state diagram 900 (FIG. 9). The system performing process 1100 can perform the activities at 1005, 1010, 1015, 1020, 1025, 1030 as in process 1000. The system can also determine if the last three beats have been ventricular beats at decision 1105. For example, the system can determine if the last three beats are marked with a ventricular beat occurrence indicator such as that received at 1010. If the system determines that the last three beats have been ventricular beats, the system triggers the end of the AF event at 1110 and, when appropriate, terminates a ventricular tachycardia event at 1115. The start and termination of the ventricular tachycardia event can transition the state of a system into and out of a V-TACH event, much like transitions 910, 915 in state diagram 900 (FIG. 9). When the V-TACH event has been terminated at 1115 or when the system determines that the last three beats have not been ventricular beats at 115, the system then determines if the average of both the weighted and preset timing comparisons in the array of the most recent beats has dropped below 0.08 at decision 1120. If the average has not dropped below 0.08, the system returns to compare the recent R to R intervals with the previous R to R interval at 1005. On the other hand, when the average has dropped below 0.08, the system triggers the end of the AF event at 1125. This triggering can transition the state of a system out of an AF event, much like transition 430 in state diagram 900 (FIG. 9). Various implementations of the systems and techniques described here can be realized in digital electronic circuitry, integrated circuitry, specially designed ASICs (application specific integrated circuits), computer hardware, firmware, software, and/or combinations thereof. These various implementations can include one or more computer programs that are executable and/or interpretable on a programmable system including at least one programmable processor, which may be special or general purpose, coupled to receive data and instructions from, and to transmit data and instructions to, a storage system, at least one input device, and at least one output device. These computer programs (also known as programs, software, software applications or code) may include machine instructions for a programmable processor, and can be implemented in a high-level procedural and/or object-oriented programming language, and/or in assembly/machine language. As used herein, the term “machine-readable medium” refers to any computer program product, apparatus and/or device (e.g., magnetic discs, optical disks, memory, Programmable Logic Devices (PLDs)) used to provide machine instructions and/or data to a programmable processor, including a machine-readable medium that receives machine instructions as a machine-readable signal. The term “machine-readable signal” refers to any signal used to provide machine instructions and/or data to a programmable processor. To provide for interaction with a user, the systems and techniques described here can be implemented on a computer having a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user and a keyboard and a pointing device (e.g., a mouse or a trackball) by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form, including acoustic, speech, or tactile input. The systems and techniques described here can be implemented in a computing environment that includes a back-end component (e.g., as a data server), or that includes a middleware component (e.g., an application server), or that includes a front-end component (e.g., a client computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the systems and techniques described here), or any combination of such back-end, middleware, or front-end components. The components of the environment can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include a local area network (“LAN”), a wide area network (“WAN”), and the Internet. The computing environment can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made. Cardiac signals other than scalar electrocardiograms such as heart sounds can be monitored. Other weighting approaches and transformation functions can be used, depending upon the manner in which the timing of beats is compared. Weight 705 can be interpolated in any of a number of different ways such as a cubic spline between points 715, 720, 725, 730, 735. Cardiac monitoring can be performed in real time or delayed. The values of different parameters can be changed and useful results still obtained. For example, in FIG. 7, point 735 can be repositioned to a comparison factor DRR(n) value above 0.2. Accordingly, other implementations are within the scope of the following claims. | <SOH> BACKGROUND <EOH>The following description relates to cardiac monitoring, for example, by monitoring cardiac electrical activity. The electrical activity of the heart can be monitored to track various aspects of the functioning of the heart. Given the volume conductivity of the body, electrodes on the body surface or beneath the skin often display potential differences related to this activity. Anomalous electrical activity can be indicative of disease states or other physiological conditions that can range from benign to deadly. One example of such a physiological condition is atrial fibrillation. Atrial fibrillation involves the loss of synchrony between the atria and the ventricles. In complex atrial fibrillation, long-lived wavelets of depolarization travel along circular paths in the atria. This can lead to irregular ventricular beating as well as blood stagnation and clotting in the atria. Atrial fibrillation is among the most common forms of cardiac arrhythmia and may affect more than two million people annually. Atrial fibrillation has been associated with stroke, congestive heart failure, and cardiomyopathy. Another example of such a physiological condition is atrial flutter. Atrial flutter also involves the loss of synchrony between the atria and the ventricles. In atrial flutter, multiple atrial waveforms reach the atrioventricular (AV) node during each ventricular beat due to, e.g., atrial scars, an atrial infarction, or a re-entrant circuit encircling a portion of the right atrium. Atrial flutter is less common than atrial fibrillation but is also associated with stroke, congestive heart failure, and cardiomyopathy. | <SOH> SUMMARY <EOH>The cardiac monitoring systems and techniques described here may include various combinations of the following features. A method can include determining a beat-to-beat variability in cardiac electrical activity, determining a relevance of the variability to one of atrial fibrillation and atrial flutter using a non-linear statistics, identifying one of an atrial fibrillation event and an atrial flutter event based on the determined relevance. The event is a period in time when the information content of the cardiac electrical activity is of increased relevance. The end of the event can be identified based on the determined relevance. An event state associated with atrial fibrillation can be transitioned into in response to identification of the event. The event can be transmitted to a remote receiver from an ambulatory patient. The relevance of the variability to atrial fibrillation can be determined by receiving information identifying a ventricular beat and assigning a preset value indicating that the variability is negatively indicative of atrial fibrillation. A ventricular tachycardia event can be identified based at least in part on the information identifying the ventricular beat. The relevance of the variability to atrial fibrillation can be determined by determining an average relevance of variability in a collection of R to R intervals. The beat-to-beat variability can be determined in a series of successive beats, e.g., by determining the variability in an interval between successive R-waves. The event can be identified by comparing the relevance of the variability to a first predetermined amount of relevance. Further, the relevance of the variability in the event can be compared to a second predetermined amount of relevance to identify the end of the event. The second predetermined amount can be lower than the first predetermined amount. A method can include collecting information describing the variability in heart rate over a series of beats, designating variability at a lower end of physiological values as being largely irrelevant to atrial fibrillation, designating variability in a midrange of physiological values as being indicative of atrial fibrillation, designating variability in an upper range of physiological values as being negatively indicative of atrial fibrillation, and determining a relevance of the variability described in the collection to atrial fibrillation. The variability can be designated by multiplying the information describing the variability by a weighting factor. Information describing a variability in R to R intervals over a series of beats can be collected. The collected information can be a function of a ratio of a first R to R interval and an immediately preceding R to R interval, such as information related to factor DRR(n) as given by DRR ( n ) = ABS ( RR ( n , n - 1 ) RR ( n , n - 1 ) + RR ( n - 1 , n - 2 ) - 1 2 ) . The variability at the lower end of physiological values can be designated as being largely irrelevant by designating information related to factors DRR(n) less than about 0.0.2 as being largely irrelevant. The variability at the midrange of physiological values can be designated as being indicative of atrial fibrillation by designating information related to factors DRR(n) greater than about 0.02 and less than about 0.15 as being indicative of atrial fibrillation. The variability at the upper range of physiological values can be designated as being negatively indicative of atrial fibrillation by designating information related to factors DRR(n) greater than about 0.157 as being negatively indicative of atrial fibrillation. Information describing the variability can be collected by collecting the variability in heart rate over a series of between 20 and 200 of the recent R to R intervals. The determined relevance of the variability can be the relevance of the variability to sustained atrial fibrillation. The series of R to R intervals can be a continuous series of R to R intervals. A method can include comparing recent R to R intervals with preceding R to R intervals to yield a collection of comparisons, weighting the comparisons according to a likelihood that the comparisons are relevant to atrial fibrillation, and determining the average relevance of the collection to atrial fibrillation. The weighting can include identifying a first of the recent beats as a ventricular beat and assigning a preset value to weight the first beat in the collection. The preset value can be negatively indicative of atrial fibrillation. The comparisons can be weighted by designating variability at a lower end of physiological values as being largely irrelevant to atrial fibrillation and designating variability in a midrange of physiological values as being indicative of atrial fibrillation. The comparisons can also be weighted by designating variability in an upper range of physiological values as being negatively indicative of atrial fibrillation. A ventricular tachycardia event can be identified based at least in part on the identification of the ventricular beat. Recent R to R intervals can be compared with immediately preceding R to R intervals to yield a collection of comparisons. The cardiac monitoring systems and techniques may provide one or more of the following advantages. Atrial fibrillation (“AFib”) and/or atrial flutter (“AFlut,” with “AF” referring to either) can be distinguished from other types of cardiac arrhythmia, such as the normal sinus rhythm irregularity, irregularity from various types of heart blocks, and the irregularity associated with premature ventricular contractions. The described systems and techniques are a practical approach to calculating the beat-to-beat irregularity while providing improved positive predictability of AF. Moreover, the described systems and techniques are able to identify sustained AF episodes, where AF continues for more that approximately 20 beats and has an increased clinical significance. For example, when the systems and techniques described here were used to analyze the MIT-BIH arrhythmia database, available from MIT-BIH Database Distribution, MIT Room E25-505A, Cambridge, Mass. 02139, USA, a sensitivity to AF in excess of 90% and a positive predictivity in excess of 96% were obtained. The described systems and techniques are well-adapted to monitoring cardiac signals of ambulatory patients who are away from controlled environments such as hospital beds or treatment facilities. The cardiac signals obtained from to ambulatory patients may be noisier and otherwise strongly impacted by the patients' heightened levels of activity. Thus, improved monitoring systems and techniques, such as those described herein, are required for ambulatory patients. The described systems and techniques are also well-adapted to real-time monitoring of arrhythmia patients, where minimal delays in distinguishing between different types of cardiac arrhythmia can speed the delivery of any urgent medical care. The described systems and techniques also require minimal computational resources. Further, the described systems and techniques do not require training before different types of cardiac arrhythmia can be distinguished. The details of one or more implementations of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. | 20040121 | 20070320 | 20050721 | 66836.0 | 0 | MANUEL, GEORGE C | CARDIAC MONITORING | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,763,224 | ACCEPTED | Headwear | Disclosed is a headwear which is mainly made of non-stretchable fiber. The headwear comprises a head receiving portion including a first stretchable fabric made of high twist yarn and a sweat band peripherally attached to the inside of the head receiving portion. Since the head receiving portion is mainly made of high twist yarn, the headwear has a fixed peripheral size but is adjustable within a predetermined range corresponding to small changes of head size. Also, the headwear can fit the head size to provide a comfortable sense of wearing. | 1. A headwear comprising a head receiving portion including a first stretchable fabric made of high twist yam; and a sweat band peripherally attached to the inside of the head receiving portion. 2. The headwear as claimed in claim 1, wherein the head receiving portion is a crown of a hat or a cap for covering a head, the crown having panels of the first stretchable fabric, the panel being stitched to form the crown. 3. The headwear as claimed in claim 1, wherein the head receiving portion is a headband for peripherally receiving a head. 4. The headwear as claimed in claim 1, wherein the first stretchable fabric is one selected from a group comprising a woven fabric, knitted fabric and non-woven fabric, wherein the first stretchable fabric includes high twist yarn. 5. The headwear as claimed in claim 4, wherein the first stretchable fabric includes the high twist yarn as weft. 6. The headwear as claimed in claim 1, wherein the sweat band includes a band core for softly pressing a head and a second stretchable fabric for partially covering the band core against the head. 7. The headwear as claimed in claim 6, wherein the second stretchable fabric includes high twist yarn. 8. The headwear as claimed in claim 7, wherein the second stretchable fabric includes an elastic material therein. 9. The headwear as claimed in claim 6, wherein the band core includes at least one selected from a group comprising woven fabric, knitted fabric, non-woven fabric and resin foam. 10. The headwear as claimed in claim 9, wherein the band core includes an elastic band layer and a polyurethane foam layer. 11. The headwear as claimed in claim 6, wherein the band core and the second stretchable fabric are stitched with a stretchable yam. 12. The headwear as claimed in claim 1, wherein lower end portions of the sweat band and the crown are wholly presses and stitched together with a stretchable yarn, along the lower edge of the crown. 13. The headwear as claimed in claim 1, further comprising a shape tape attached to the crown, along the lower edge of the crown. | BACKGROUND OF THE INVENTION 1. Field of the invention The present invention relates to a headwear, more particularly, relates to a headwear that fits a variety of head sizes and can slightly expand to fit different head sizes. 2. Description of the Prior Art A baseball cap generally includes a crown, a visor and a sweat band. The crown receives a wearer's head and fixes the cap on the head. Accordingly, it is formed substantially in the shape of a hollow hemisphere. The crown, in general, is composed of panels or gores, which are successively stitched to form the crown. The visor is attached to the front portion of the lower edge of the crown, to protect the eyes from excessive sunlight. The sweat band is peripherally attached to the inside of the crown, along a lower edge thereof, such that it circumferentially contacts the head. The sweat band absorbs sweat to prevent it from running down onto the wearer's face, and presses the head to fix the cap on the head. Because people have different sizes of head, size adjustable caps are preferred to fill this need. In order to meet this demand, several types of headwear have been designed, such as an adjustable cap, a free size cap and a sized cap. FIG. 1 is a rear perspective view of a conventional adjustable cap. Referring to FIG. 1, the conventional adjustable cap 10 includes a crown 20 and a visor 30. The crown 20 is composed of a plurality of gores, which are connected one by one to form the crown 20. The visor 30 is attached to the crown 10 at the front portion thereof. Additionally, a sweat band may be formed on the inside of the crown 20. In order to fit a range of head sizes, the adjustable cap 10 includes a size adjustable part, which is composed of a rear opening, a strap 42 and a buckle 44. The rear opening is formed at the rear portion of the lower edge of the crown 20. The strap 42 is provided at one end of the rear opening and the buckle 44 is at the other end corresponding to the strap 42. By lengthening or shortening the length of the strap 42 and buckling it to the buckle 44, the peripheral size of the crown 10 can be adjusted depending on the head size of the wearer. However, the adjustable cap 10 has a drawback in that some of the wearer's hairs coming out from the rear opening, and the lower edge of the crown could be partially wrinkled or crumpled. This drawback and the wrinkling affect the aesthetic appearance of the cap. Also, it requires a wearer to manually adjust the length of the strap 42 depending on his/her own head size. Compared with the adjustable cap, a free size cap is capable of fitting a relatively broad range of head sizes without the use of a buckle and strap, so that it overcomes some of the above problems associated with the adjustable cap. Generally, in a free size cap, the crown and/or sweat band can be elastically stretchable in the direction of circumference so as to fit a broad range of head sizes. In this instance, the crown and/or the sweat band are composed of elastic material, for example spandex or polyurethane. When the crown and/or the sweat band are stretched depending on the head sizes, they have the restoring force and press the head in return. The restoring force of the stretchable elastic fabric helps the cap to hold the head. However, the more the crown is stretched, the bigger the pressing force applied to the head. Also, this pressing force is continuously applied to the head, when in use. So, the wearer could find it uncomfortable when he/she wears it, and it could leave an indent mark on the head after wearing for a long time. Moreover, since the crown of a free size cap is made up of stretchable fabric, there is a problem that the crown can be wrinkled and cannot maintain its aesthetic shape when not in use. Some prior arts are known concerning to the free size cap, as follows. U.S. Pat. No. 6,131,202 to Yan relates to a multi-axially stretchable cap. According to the Yan patent, the gores of the cap are composed of multi-axially stretchable fabric, in which stretchable synthetic fiber are woven in both directions, as weft and wrap. Also, a sweat band includes a thin layer of synthetic foam material. Thus, the stretchable cap can stretch in weft and warp direction to provide an easy fit for the head. However, as the above described, the synthetic fabric can press the head with a large restoring force, when in use. Also, since the warp expands and contract in longitudinal direction and the weft in circumferential direction, the restoring forces by the weft and the warp are applied to the head independently. So, the restoring force by the weft is applied not associating with the warp, such that the wearer might still have an uncomfortable feeling while wearing the cap, in a manner similar to other free size caps. Further more, in case that the warp is elastically stretchable, the restoring force of the warp can draw the crown upward while wearing the cap, so to present the wearer an unpleasant feeling of wearing. U.S. Pat. No. 6,347,410 to Lee relates to a self-sizing cap. The self-sizing cap of the Lee patent includes a crown portion, a visor and a sweat band. The crown portion is composed of triangle-shaped fabric panels and it can accommodate a range of head sizes comfortably. The sweat band is composed of two or more layers shaped into an elongated rectangle. The lower edge of the sweat band is flexibly attached to the lower peripheral edge of the crown portion, such that the sweat band can be stowed or deployed. When the sweat band is deployed, it can expand the attachment area on the wearer's head and provide more shade and warmth, and also it can have matching or contrasting color combinations. PCT application No. WO01/05259 relates to a cap with a stretchable band. The cap includes a crown and an inner band, wherein the inner band is elastically stretchable along its direction of elongation and includes a liner for encircling the head comfortably. The crown is composed of gores and at least one of the gores is made of elastically stretchable material. The abovementioned three patent references all are related to free size caps, which fit a relatively broad range of head sizes. The crowns of the free size caps continuously press the head and might provide the wearer with an uncomfortable feeling when in use. Moreover, the more the free size cap stretches, the more heavily the cap presses the head. On the other hand, a sized cap is mainly made of non-stretchable material and has a fixed peripheral size. The sized cap generally includes a crown and a sweat band, which are mainly made of non-stretchable fiber. It does not have a rear opening for size adjustment, and does not elastically expand and contract. Thus, the crown of the sized cap is not wrinkled or crumpled, providing a good appearance. The sized cap can best fit only one head size. However, it follows that many different sizes of caps should be fabricated for different head sizes. Also, depending on one's hairstyle and/or length, a sized cap could feel either too tight or loose, such that it could occasionally make the wearer feel uncomfortable. SUMMARY OF THE INVENTION It is an object of the present invention to provide a headwear that has a fixed peripheral size but is adjustable within a predetermined range corresponding to small changes of head size. It is another object of the present invention to provide a headwear that fits the wearer comfortably. To achieve the objects of the present invention, there is provided a headwear comprising a head receiving portion and a sweat band, wherein the head receiving portion includes first stretchable fabric mainly made of non-stretchable fiber, namely an improved sized cap. The head receiving portion may be a crown or a head band. The crown is usually used to a cap or a hat for covering a head, and includes a plurality of panels. The panels are made of the first stretchable fabric and are stitched one by one to form the crown. While the headband may be used to a visor-type cap to peripherally receive the head. The first stretchable fabric might be woven fabric, knitted fabric or non-woven fabric, wherein the fabrics are substantially made of non-stretchable fiber. Preferably, the first stretchable fabric includes high twist yam. To fabricate high twist yam, non-stretchable fibers are twisted over 800 times per meter in S or Z twist. Generally, the high twist yams that are twisted about 1,000˜3,000 times are widely used for commercial purposes. Though high twist yam is made of non-stretchable fiber, it can slightly stretch due to its unique structural features. Accordingly, the crown composed of high twist yam can fit the wearer's head, despite some changes in its peripheral size. The sweat band is peripherally attached to the inside of the head receiving portion, more particularly, attached there along the lower edge of the head receiving portion. The sweat band absorbs sweat to prevent it from running down onto the face and slightly presses the circumference of the head to fix the headwear in place. Preferably, the sweat band may include a band core and a second stretchable fabric. The band core, as a center portion of the sweat band, presses the head softly, and the second stretchable fabric partially receives the band core to cover it against the head. The band core includes soft material, for example polyurethane foam, other resin foam, woven fabric, knitted fabric, non-woven fabric, etc. The second stretchable fabric is composed of high twist yarn, allowing it to slightly expand and contract in a small range of peripheral size. Also, the second stretchable fabric could include elastic material as weft, such as spandex and polyurethane, so the sweat band can stretch more elastically than the head receiving portion. Thus the sweat band can fit the head in spite of some changes in head peripheral size, and can contact and press the head comfortably, neither too tightly nor loosely. Additionally, a visor, a bill or a brim can be secured to the head receiving portion and extend outwardly. For example, in case that the headwear is a cap or an ivy cap, a visor might be formed at the front portion of a crown, and in case that the headwear is a hat, a brim might be formed along the lower edge of the crown, and still another headwear such as a visor-type cap might include a visor or a bill at the front portion of the headband. Namely, headwears of the present invention, such as a cap, a hat, an ivy cap, a visor-type cap, etc., can have a visor, a bill or a brim. According to the present invention, the headwear has one head size and can slightly expand and contract to fit a head of the one head size, depending on some changes of hair style or length. Also, the headwear can fit heads of people who have almost the same but minutely different head sizes. BRIEF DESCRIPTION OF THE DRAWINGS The above objects and other advantages of the present invention will be more apparent by describing preferred embodiments thereof in detail with reference to accompanying drawings in which: FIG. 1 is a rear perspective view of a conventional adjustable cap; FIG. 2 is a partially cut view of a headwear according to a first embodiment of the present invention; FIG. 3 is a sectional view of a sweat band of the headwear of FIG. 2; FIG. 4 is a partially cut view of a sweat band and a lower edge of a crown in a headwear according to a second embodiment of the present invention; and FIG. 5 is a sectional view of the sweat band of the headwear of FIG. 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 2 is a partially cut view of a headwear according to the embodiment 1 of the present invention, and FIG. 3 is a sectional view illustrating a sweat band of the headwear of FIG. 2. Referring to FIG. 2 and FIG. 3, the headwear is a cap 100 for a baseball player or a kid, which includes a crown 110, a visor 120 and a sweat band 130. The crown 110 is made up of plurality of gores 112. The gores 112 are successively stitched one by one, to form a hemisphere-shaped crown 110. Two of the gores 112 are stitched to form an inseam. A bias tape 114 is provided over the inseam between two adjacent gores on the inner side of the crown 110. Also, the bias tape 114 helps to prevent the gores 112 from being deformed. Each of the gores 112 includes a first stretchable fabric mainly composed of high twist yarn. The high twist yarn generally is made of non-stretchable fibers that are twisted over 800 times per meter. The high twist yarn has slight expansion properties. Although the high twist yarn is made of non-stretchable fibers, it can expand and contract because of its high-twist structural feature. Here, the high twist yarn is included in the gore 112 as weft or warp, otherwise at least as weft, to help the crown 110 to expand circumferentially. Also, the gores 112 of this embodiment could be woven fabric, knitted fabric or non-woven fabric made of the high twist yarn. The visor 120 has rigid nature and is secured to a front portion of the crown 110. It extends outwardly to protect a face or a neck from becoming sun burnt and eyes from sunlight. The sweat band 130 is attached to the inside of the crown 110 along its lower edge to fix the cap 100 on the head. The sweat band 130 absorbs sweat to prevent it from running down onto the face. Particularly, the lower end portion of the crown 110 is inwardly bent, and the sweat band 130 is overlaid on. The lower edge of the crown 110 and the sweat band 130 are engaged with each other by the inwardly bent portion of the crown 110. The lower end portions of the sweat band 130 and the crown 110 are wholly pressed and stitched together to form a stitch line 146 that encircles the crown 110, parallel to its lower edge. The stitch line 146 is visible on the outer side of the crown 110 to provide an aesthetically pleasing appearance. The sweat band 130 includes a band core 132 therein. The band core 132 is partially covered by a second stretchable fabric 136. The second stretchable fabric 136 is also mainly made of a high twist yam described above or could include some elastic material like spandex, polyurethane, etc. When the second stretchable fabric includes elastic material, the second stretchable fabric 136 can stretch more elastically than the first stretchable fabric. The band core 132 is composed of soft materials. This allows the sweat band 130 to wrap softly around the head, so to reduce pressing force and provide a comfortable fit. Also, the band core 132 helps to maintain the shape of the sweat band 130. The band core 132 can be made of polyurethane foam, other resin foam, woven fabric, knit fabric and non-woven fabric. The second stretchable fabric 136 is disposed so that its weft direction is substantially parallel or somewhat inclined to the circumference of the sweat band 130. The second stretchable fabric 136 would be interposed between the band core 132 and the head, when in use, and partially covers upper and lower end portions of the band core 132, so to cover the inner face of the band core 132. When the second stretchable fabric 136 is engaged with the band core 132, the upper and lower end portions of the sweat band 130 are stitched with a stretchable yarn 142 and 144. Also, when the sweat band 130 is stitched to the crown 110, a stretchable yarn also is preferably used, so to form a stitch line 146. At this time, the lower end portions of the sweat band 130 and the crown 110 are wholly pressed and stitched together with the stretchable yam, such that the stitch line 146 is visible on the outer side of the crown 110 and formed along the lower edge of the crown 110. Since the stretchable yarns for engaging the sweat band 130 and the crown 110 and for forming the stitch line 146 have stretchable properties, they can easily stretch corresponding to the expanding and contracting of the crown 110 and the sweat band 130. Thus, the stretchable yams can regulate the appearance of the crown 110, and the stitch line 146, specially, can present the cap 100 with an aesthetically pleasing appearance. When the wearer puts on the cap 100, the crown 110 and the sweat band 130 slightly expand so that it can accommodate a limited number of head sizes. As shown in FIG. 3, the lower end portion of the sweat band 130 is fixedly attached to the lower end portion of the crown 110, while the upper portion of the sweat band 130 is separated from the inner side of the crown 110. So, the upper portion of the sweat band 130 can move for a comfortable fit. In sum, because the sweat band 130 and the crown 110 include high twist yams according to embodiment 1, the cap 100 has an expanding property to a small degree. Therefore the cap 100 has smaller restoring force than the conventional free size cap, thus leaving no indented mark on the forehead. Additionally, the band core 132 made of a soft material makes the sweat band 130 wrap softly around the head, so to reduce the pressing force and provide a comfortable fit. In embodiment 1, the cap 100 is described in detail as the headwear of the present invention. However, the headwear of the present invention might include a hat and ivy cap having a few panels, and a visor-type cap having a head band, etc., and the above descriptions can help to understand other styles of headwear. Embodiment 2 FIG. 4 is a partially cut view illustrating a sweat band and a crown of a headwear according to embodiment 2 of the present invention, and FIG. 5 is a sectional view of the sweat band of the headwear. In the embodiment 2, the headwear can be described with reference to the detail descriptions and drawings of the above embodiment, so that repeated descriptions and drawings may be omitted. Referring to FIG. 4 and FIG. 5, the headwear is a cap for a baseball player or a child, and the cap includes a crown 210, a visor 220 and a sweat band 230. The crown 210 is made up of plurality of gores 212. The gores 212 are successively stitched one by one, to form a hemisphere-shaped crown 210. Two of the gores 212 are stitched to form an inseam. A bias tape 214 is provided over the inseam between two adjacent gores on the inner side of the crown 210. Also, the bias tape 214 helps to prevent the gores 212 from being deformed. Each of the gores 212 includes a first stretchable fabric mainly composed of high twist yarn. The high twist yarn generally is made of non-stretchable fibers that are twisted over 800 times per meter. The high twist yarn has slight expansion properties. Although the high twist yarn is made of non-stretchable fibers, it can expand and contract because of its high-twist structural feature. Here, the high twist yarn is included in the gore 212 as weft or warp, otherwise at least as weft, to help the crown 210 to expand circumferentially. Also, the gores 212 of this embodiment could be woven fabric, knitted fabric or non-woven fabric made of the high twist yarn. The visor 220 has rigid nature and is secured to a front portion of the crown 210. It extends outwardly to protect a face or a neck from becoming sun burnt and eyes from sunlight. The sweat band 230 is attached to the inside of the crown 210, along its lower edge. The sweat band 230 can fix the cap 200 on the head and absorb sweat to prevent it from running down on the face. Particularly, the lower end portion of the crown 210 is partially folded to the inside and the sweat band 230 is overlaid on and stitched to the folded portion of the crown 210. The lower end portions of the sweat band 230 and the crown 210 are stitched together to form a stitch line 246 that encircles the crown 210 and is parallel to its lower edge. The stitch line 246 is visible on the outer side of the crown 210 to provide an aesthetically pleasing appearance. The sweat band 230 includes a band core 232 therein, and the band core 232 is composed of a polyurethane form layer 233 inward and an elastic band layer 234 outward. The polyurethane form layer 233 is partially covered by a second stretchable fabric 236 to face the head. The second stretchable fabric 236 is mainly made of high twist yam described above and could include some elastic material like spandex, polyurethane, etc. When the second stretchable fabric includes the elastic material, it can stretch more elastically than the first stretchable fabric. The polyurethane foam layer 233 is formed inside of the band core 232 and is made of very soft material. So, it makes the sweat band 230 wrap the head softly around the head, so to reduce pressing force and provide a comfortable fit. Also, the polyurethane foam layer 233 helps to maintain the shape of the sweat band 230, when not in use. The elastic band layer 234 is formed outside of the band core 232 and is made of elastic material, so to provide a proper restoring force. The second stretchable fabric 236 is disposed so that its weft direction is substantially parallel or somewhat inclined to the circumference of the sweat band 230. The second stretchable fabric 236 would be interposed between the band core 232 and the head, when in use, and partially covers upper and lower end portions of the band core 232, so to cover the inner face of the band core 232. When the second stretchable fabric 236 is engaged with the band core 232, the upper and lower end portions of the sweat band 230 are stitched with a stretchable yarn 242 and 244. Also, when the sweat band 230 is stitched to the crown 210, a stretchable yarn is preferably used, so to form a stitch line 246. At this time, the lower end portions of the sweat band 230 and the crown 210 are stitched together and the stitch line 246 is formed adjacent to and parallel to along the lower edge of the crown 210. Since the stitch line 246 is made of a stretchable yarn, they can stretch corresponding to the expanding and contracting of the crown 210 and the sweat band 230. The stitch 246 can regulate the appearance of the lower end portion of the crown 210 to present the cap 200 with an aesthetically pleasing appearance. A shape tape 218 is attached circumferentially to the crown 210, adjacent to the lower edge thereof. The shape tape 218 is stitched along the folded portion of the crown 210. As the wearer puts on and takes off the cap repeatedly, the crown 210 also expand and contract repeatedly, in which case the crown 210 is likely to become deformed and wrinkled. In order to prevent the cap from becoming deformed and/or wrinkled, the shape tape 218 is stitched circumferentially to the crown 210. Referring to FIG. 5, when the wearer puts on the cap, the crown 210 and the sweat band 230 slightly expand so that it can accommodate a limited number of head sizes. The lower end portion of the sweat band 230 is fixedly attached to the lower end portion of the crown 210, while the upper portion of the sweat band 230 is separated from the inner side of the crown 210. So, the upper portion of the sweat band 230 can additionally move for a comfortable fit. Because the sweat band 230 and the crown 210 include high twist yarns, the cap can expand circumferentially to a small degree. Also, the cap according to the present invention has smaller restoring force than the conventional free size cap, thus leaving no indent mark on the wearer's forehead. Moreover, the sweat band 230 including the soft band core 232 wraps softly around the head, so to reduce the pressing force and provide a comfortable fit. Although the preferred embodiments of the present invention have been described, it is understood that the present invention should not be limited to those preferred embodiments, but various changes and modifications can be made by one skilled in the art within the spirit and scope of the invention as hereinafter claimed. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the invention The present invention relates to a headwear, more particularly, relates to a headwear that fits a variety of head sizes and can slightly expand to fit different head sizes. 2. Description of the Prior Art A baseball cap generally includes a crown, a visor and a sweat band. The crown receives a wearer's head and fixes the cap on the head. Accordingly, it is formed substantially in the shape of a hollow hemisphere. The crown, in general, is composed of panels or gores, which are successively stitched to form the crown. The visor is attached to the front portion of the lower edge of the crown, to protect the eyes from excessive sunlight. The sweat band is peripherally attached to the inside of the crown, along a lower edge thereof, such that it circumferentially contacts the head. The sweat band absorbs sweat to prevent it from running down onto the wearer's face, and presses the head to fix the cap on the head. Because people have different sizes of head, size adjustable caps are preferred to fill this need. In order to meet this demand, several types of headwear have been designed, such as an adjustable cap, a free size cap and a sized cap. FIG. 1 is a rear perspective view of a conventional adjustable cap. Referring to FIG. 1 , the conventional adjustable cap 10 includes a crown 20 and a visor 30 . The crown 20 is composed of a plurality of gores, which are connected one by one to form the crown 20 . The visor 30 is attached to the crown 10 at the front portion thereof. Additionally, a sweat band may be formed on the inside of the crown 20 . In order to fit a range of head sizes, the adjustable cap 10 includes a size adjustable part, which is composed of a rear opening, a strap 42 and a buckle 44 . The rear opening is formed at the rear portion of the lower edge of the crown 20 . The strap 42 is provided at one end of the rear opening and the buckle 44 is at the other end corresponding to the strap 42 . By lengthening or shortening the length of the strap 42 and buckling it to the buckle 44 , the peripheral size of the crown 10 can be adjusted depending on the head size of the wearer. However, the adjustable cap 10 has a drawback in that some of the wearer's hairs coming out from the rear opening, and the lower edge of the crown could be partially wrinkled or crumpled. This drawback and the wrinkling affect the aesthetic appearance of the cap. Also, it requires a wearer to manually adjust the length of the strap 42 depending on his/her own head size. Compared with the adjustable cap, a free size cap is capable of fitting a relatively broad range of head sizes without the use of a buckle and strap, so that it overcomes some of the above problems associated with the adjustable cap. Generally, in a free size cap, the crown and/or sweat band can be elastically stretchable in the direction of circumference so as to fit a broad range of head sizes. In this instance, the crown and/or the sweat band are composed of elastic material, for example spandex or polyurethane. When the crown and/or the sweat band are stretched depending on the head sizes, they have the restoring force and press the head in return. The restoring force of the stretchable elastic fabric helps the cap to hold the head. However, the more the crown is stretched, the bigger the pressing force applied to the head. Also, this pressing force is continuously applied to the head, when in use. So, the wearer could find it uncomfortable when he/she wears it, and it could leave an indent mark on the head after wearing for a long time. Moreover, since the crown of a free size cap is made up of stretchable fabric, there is a problem that the crown can be wrinkled and cannot maintain its aesthetic shape when not in use. Some prior arts are known concerning to the free size cap, as follows. U.S. Pat. No. 6,131,202 to Yan relates to a multi-axially stretchable cap. According to the Yan patent, the gores of the cap are composed of multi-axially stretchable fabric, in which stretchable synthetic fiber are woven in both directions, as weft and wrap. Also, a sweat band includes a thin layer of synthetic foam material. Thus, the stretchable cap can stretch in weft and warp direction to provide an easy fit for the head. However, as the above described, the synthetic fabric can press the head with a large restoring force, when in use. Also, since the warp expands and contract in longitudinal direction and the weft in circumferential direction, the restoring forces by the weft and the warp are applied to the head independently. So, the restoring force by the weft is applied not associating with the warp, such that the wearer might still have an uncomfortable feeling while wearing the cap, in a manner similar to other free size caps. Further more, in case that the warp is elastically stretchable, the restoring force of the warp can draw the crown upward while wearing the cap, so to present the wearer an unpleasant feeling of wearing. U.S. Pat. No. 6,347,410 to Lee relates to a self-sizing cap. The self-sizing cap of the Lee patent includes a crown portion, a visor and a sweat band. The crown portion is composed of triangle-shaped fabric panels and it can accommodate a range of head sizes comfortably. The sweat band is composed of two or more layers shaped into an elongated rectangle. The lower edge of the sweat band is flexibly attached to the lower peripheral edge of the crown portion, such that the sweat band can be stowed or deployed. When the sweat band is deployed, it can expand the attachment area on the wearer's head and provide more shade and warmth, and also it can have matching or contrasting color combinations. PCT application No. WO01/05259 relates to a cap with a stretchable band. The cap includes a crown and an inner band, wherein the inner band is elastically stretchable along its direction of elongation and includes a liner for encircling the head comfortably. The crown is composed of gores and at least one of the gores is made of elastically stretchable material. The abovementioned three patent references all are related to free size caps, which fit a relatively broad range of head sizes. The crowns of the free size caps continuously press the head and might provide the wearer with an uncomfortable feeling when in use. Moreover, the more the free size cap stretches, the more heavily the cap presses the head. On the other hand, a sized cap is mainly made of non-stretchable material and has a fixed peripheral size. The sized cap generally includes a crown and a sweat band, which are mainly made of non-stretchable fiber. It does not have a rear opening for size adjustment, and does not elastically expand and contract. Thus, the crown of the sized cap is not wrinkled or crumpled, providing a good appearance. The sized cap can best fit only one head size. However, it follows that many different sizes of caps should be fabricated for different head sizes. Also, depending on one's hairstyle and/or length, a sized cap could feel either too tight or loose, such that it could occasionally make the wearer feel uncomfortable. | <SOH> SUMMARY OF THE INVENTION <EOH>It is an object of the present invention to provide a headwear that has a fixed peripheral size but is adjustable within a predetermined range corresponding to small changes of head size. It is another object of the present invention to provide a headwear that fits the wearer comfortably. To achieve the objects of the present invention, there is provided a headwear comprising a head receiving portion and a sweat band, wherein the head receiving portion includes first stretchable fabric mainly made of non-stretchable fiber, namely an improved sized cap. The head receiving portion may be a crown or a head band. The crown is usually used to a cap or a hat for covering a head, and includes a plurality of panels. The panels are made of the first stretchable fabric and are stitched one by one to form the crown. While the headband may be used to a visor-type cap to peripherally receive the head. The first stretchable fabric might be woven fabric, knitted fabric or non-woven fabric, wherein the fabrics are substantially made of non-stretchable fiber. Preferably, the first stretchable fabric includes high twist yam. To fabricate high twist yam, non-stretchable fibers are twisted over 800 times per meter in S or Z twist. Generally, the high twist yams that are twisted about 1,000˜3,000 times are widely used for commercial purposes. Though high twist yam is made of non-stretchable fiber, it can slightly stretch due to its unique structural features. Accordingly, the crown composed of high twist yam can fit the wearer's head, despite some changes in its peripheral size. The sweat band is peripherally attached to the inside of the head receiving portion, more particularly, attached there along the lower edge of the head receiving portion. The sweat band absorbs sweat to prevent it from running down onto the face and slightly presses the circumference of the head to fix the headwear in place. Preferably, the sweat band may include a band core and a second stretchable fabric. The band core, as a center portion of the sweat band, presses the head softly, and the second stretchable fabric partially receives the band core to cover it against the head. The band core includes soft material, for example polyurethane foam, other resin foam, woven fabric, knitted fabric, non-woven fabric, etc. The second stretchable fabric is composed of high twist yarn, allowing it to slightly expand and contract in a small range of peripheral size. Also, the second stretchable fabric could include elastic material as weft, such as spandex and polyurethane, so the sweat band can stretch more elastically than the head receiving portion. Thus the sweat band can fit the head in spite of some changes in head peripheral size, and can contact and press the head comfortably, neither too tightly nor loosely. Additionally, a visor, a bill or a brim can be secured to the head receiving portion and extend outwardly. For example, in case that the headwear is a cap or an ivy cap, a visor might be formed at the front portion of a crown, and in case that the headwear is a hat, a brim might be formed along the lower edge of the crown, and still another headwear such as a visor-type cap might include a visor or a bill at the front portion of the headband. Namely, headwears of the present invention, such as a cap, a hat, an ivy cap, a visor-type cap, etc., can have a visor, a bill or a brim. According to the present invention, the headwear has one head size and can slightly expand and contract to fit a head of the one head size, depending on some changes of hair style or length. Also, the headwear can fit heads of people who have almost the same but minutely different head sizes. | 20040126 | 20100316 | 20050728 | 97819.0 | 0 | QUINN, RICHALE LEE | FREE-SIZE HEADWEAR | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,763,323 | ACCEPTED | Noise-free low-power consumption wide voltage range DC and AC contactor and remote telephone control system using the same | A noise-free low-power consumption wide voltage range DC and AC contactor and remote telephone control system is disclosed. A movable iron core is connected to a linkage. Another end of the linkage is connected to a micro switch. A normal close contact of the micro switch is serially connected to a magnetic coil and is parallel connected to an IC circuit and a retaining coil. A lower end of the movable iron coil is in the extent of the coil so that the magnetic coil attracts the movable iron core to move downwards to conduct the contactor and meanwhile, the magnetic coil will disconnect. The retaining coil is used to replaced the magnetic coil to attract the movable iron core. Since the power consumption of the retaining coil is small and thus the contactor is noise free, lower power consumption, and wide voltage range. Three voltage stages are selectable. The connector can be used with a telephone, a telephone wire, a voice system, a keyboard and a software program so as to be formed as a remote telephone control system with a simple structure, lower cost and be a multi-functional device. Thereby, it can be used widely. | 1. A noise-free low-power consumption wide voltage range DC and AC contactor comprising: a housing; an static iron core installed on an inner bottom of the housing; an movable copper installed in an inner top of the housing; each of two ends of the movable copper having a respective movable silver spot; static silver spots being installed below the movable silver spots; two stationary coppers connected to a wall of the housing; each of the stationary coppers being installed with a respective one of the static silver spots; a middle part of the movable copper being connected to a movable iron core; a spring installed between a bottom of the moveable iron core and an inner bottom of the static iron core on the housing; a magnetic coil wound around one leg of the static iron core; a retaining coil wound around another leg of the static iron core; characteristic in that a linkage having one end connected to the moveable iron core; a micro switch connected to another end of the linkage; the micro switch being connected to the magnetic coil, an integrated circuit and the retaining coil; wherein the bottom of the moveable iron core is within longitudinal extents of the magnetic coil and retaining coil. 2. The noise-free low-power consumption wide voltage range DC and AC contactor as claimed in claim 1, wherein the micro switch has a normally closed contact point; the contact point is connected to the magnetic coil; the integrated circuit is connected to a retaining coil in parallel. 3. The noise-free low-power consumption wide voltage range DC and AC contactor as claimed in claim 1, wherein the contactor is used with a telephone, a telephone input wire, a voice system, a keyboard and software program so as to be formed as a remote telephone control system. 4. The noise-free low-power consumption wide voltage range DC and AC contactor as claimed in claim 1, wherein the contactor is combined with a remote telephone control system so as to form as a control device; the control device is connected to a public power supply system directly and then the telephone wire is connected so that the telephone wire is conducted so as to achieve the object of control. 5. The noise-free low-power consumption wide voltage range DC and AC contactor as claimed in claim 1, wherein the number of the telephone is according to the number of electric device to be controlled. | FIELD OF THE INVENTION The present invention relates to electric contactors, and particular to a noise-free low-power consumption wide voltage range dc and ac contactor and remote telephone control system using the same, which can be used to a remote telephone control system comprising a telephone, a keyboard, a software program, and a voice system. BACKGROUND OF THE INVENTION In the prior art communication contactors, the magnetic coils are used to attract an iron coil and preventing it from being ejected back during the usage of the communication contactor. The magnetic coil must be kept in actuation, thereby causing the magnetic coil to make noise due to continuous actuation. This prior art consumes larger electric power, meanwhile operating cost is increased. Noise not only makes the background too noisy but also shortens the lifetime of the contactor. Due to the large bulk of communication contactor with high cost and large noise, if it is desired to make a noiseless contactor, the volume will become larger and wires are more and more complicated. Thereby, remote telephone control systems using the prior arts are not used widely. Thereby, the prior art contactor still has many drawbacks and is not a preferred design. Thereby, it is necessary to be improved. For improving the above said defects, the inventor of the present invention has create a new design which can improve the prior art defects. SUMMARY OF THE INVENTION Accordingly, the primary object of the present invention is to provide a noise-free low-power consumption wide voltage range dc and ac contactor and remote telephone control system using the same, wherein an iron coil is attracted and a retaining coil is used to replace a magnetic coil. Thereby, noise can be reduced and power consumption is also reduced. The magnetic coil is worked in a short time and work transiently. The voltage used is wide, which includes the following three ranges: 1. A first band is from2V˜120V which is commonly for DC and AC, including DC/AC voltage of 2V, 4V, 6V, 8V, 9V, 12V, 24V, 48V, 65V, 80V, 100V, 110V, 120V, etc. 2. A second band is from 100V to 250V which is commonly for DC and AC, including DC/AC of 100V, 110, 120V, 200V, 220V, 240V, 250V, etc. 3. A third band is from 200V to 480V which is commonly for DC/AC, including DC and AC of 200V, 220V, 240V, 250V, 275V, 380V, 415V, 440, 480V. The present invention can be used widely with a range from 0.1 A to 2000 A DC or AC contactor. Moreover, the present invention is simple, lower noise, lower power consumption, lower cost with a small volume. To achieve above object, the present invention provides a noise-free low-power consumption wide voltage range DC and AC contactor comprising: a housing; an static iron core installed on an inner bottom of the housing; an movable copper installed in an inner top of the housing; each of two ends of the movable copper having a respective movable silver spot; static silver spots being installed below the movable silver spots; two stationary coppers connected to a wall of the housing; each of the stationary coppers being installed with a respective one of the static silver spots; a middle part of the movable copper being connected to a movable iron core; a spring installed between a bottom of the moveable iron core and an inner bottom of the static iron core on the housing; a magnetic coil wound around one leg of the static iron core; a retaining coil wound around another leg of the static iron core; characteristic in that a linkage having one end connected to the moveable iron core; a micro switch connected to another end of the linkage; the micro switch being connected to the magnetic coil, an integrated circuit and the retaining coil; wherein the bottom of the moveable iron core is within longitudinal extents of the magnetic coil and retaining coil. The connector can be used with a telephone, a telephone wire, a voice system, a keyboard and a software program so as to be formed as a remote telephone control system with a simple structure, lower cost and be a multi-functional device. Thereby, it can be used widely. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing the noise-free low-power consumption wide voltage range dc and ac contactor of the present invention. FIG. 2 is a circuit diagram of the magnetic coils, retaining coil and IC circuit of the noise-free low-power consumption wide voltage range dc and ac contactor of the present invention. FIG. 3 shows the structure of the noise-free low-power consumption wide voltage range dc of the present invention. FIG. 4 is a flow diagram about the processing of the noise-free low-power consumption wide voltage range dc and ac contactor of the present invention. FIG. 5 shows the outer appearance of the remote telephone control system using the noise-free low-power consumption wide voltage range dc and ac contactor of the present invention. DETAIL DESCRIPTION OF THE INVENTION As shown in FIGS. 1 and 2, the structural schematic view of noise-free low-power consumption wide voltage range dc and ac contactor of the present invention and the circuit connection of the magnetic coils and retaining coils and IC circuit of the present invention are illustrated. It is shown that the voltage control communication contactor includes a housing 1. A static iron core 14 is located at the inner bottom of the housing 1. A movable copper 2 is installed at the inner top of housing 1. The two ends of the movable copper 2 are installed respective movable silver spots 3. Two stationary coppers 4 are connected to the housing 1. Each of the stationary coppers 4 is installed with a respective static silver spot 5. The static silver spot 5 is directly faced to the respective bottoms of active silvers spots 3. Middle ends of movable coppers 2 are connected to an moveable iron core 6. The bottom of moveable iron core 6 is within the range of magnetic coil 7. A spring 8 is installed between a bottom of the moveable iron core 6 and an inner bottom of the static iron core 14 on housing 1. In the present invention, a linkage 9 has one end being connected to the moveable iron core 6; and another end of the linkage 9 is connected with a micro switch 10. The micro switch 10 has a normally closed contact point 11. The contact point 11 is serially connected to the magnetic coil 7. Signals are transferred from the magnetic coil 7 to an IC circuit (integrated circuit) 12. The IC circuit 12 is connected to a retaining coil 13. The contact point 11 and magnetic coil 7 are coupled to the circuit 12 and retaining coil 13. The retaining coil 13 is near the inner bottom the housing 1. The bottom of moveable iron core 6 is kept within the range of the retaining coil 13 because the magnetic coil 7 has been attracted by the moveable iron core 6. Therefore the retaining coil 13 can be placed under the magnetic coil 7. Above said components constructs the noise-free low-power consumption wide voltage range dc and ac contactor 15 of the present invention, as shown in FIG. 3. Before the actuation of the contactor 15, as shown in FIG. 1, the magnetic coil 7 has a current flowing therethrough. The moveable iron core 6 is not attracted, and the movable silver spot 3 is disconnected from the static silver spot 5. Therefore, the contactor is inoperable. When the contactor 15 is actuated, as shown in FIGS. 1 and 2, the magnetic coil 7 is induced as switch K closes. It then attracts the moveable iron core 6 so as to compress the spring 8. The movable copper 2 moves downwards and the movable silver spots 3 are connected to the static silver spots 5 on stationary coppers 4. The circuit is conductive and the contactor 15 works. As the moment that the contact point of each movable silver spot 3 is in contact with the static silver spots 5, the linkage 9 from the moveable iron core 6 moves downward to be connected to the micro switch 10. Thereby, the contact point 11 will disconnect magnetic coil 7, and thus the magnetic coil 7 does not conduct. The signals generated from the magnetic coil 7 which is now non-conducted is transferred to the retaining coil 13 through the IC circuit 12 so as to keep the conduction of the retaining coil 13. Since when the moveable iron core 6 is kept within the extent of the retaining coil 13, the coil 13 can grip moveable iron core 6 no matter how small the power is. Thereby, the spring 8 cannot resilient. The contactor 15 keeps in actuation. Since the retaining coil 13 is designed to have fewer coils, a smaller diameter, lower power than those of the magnetic coil 7, in order that the magnetic coil 7 could attract the moveable iron core 6, it is necessary to consume more power. If the coil 7 still attracts after the moveable iron core 6 is attracted, then large noise and power generates. Therefore it is only necessary to keep the retaining coil 13 in actuation for replacing the magnetic coil to eliminate noise and keep the power down. If the whole contactor 15 short circuits outsides, this will keep the retaining coil 13 and magnetic coil 7 from working. Moveable iron core 6 will be ejected upwards from the spring 8. Contactor 15 will not work until the outside is powered to repeat the above steps. If the IC circuit 12 receives negative pulse signals as the magnetic coil 7 interrupts from conduction and then to cause the keep coil 13 work. Since it is connected to magnetic coil 7 in parallel, the original circuit is still connected, contactor 15 still works. As shown in FIGS. 3, 4, and 5,a remote telephone control system using the noise-free low-power consumption wide voltage range dc and ac contactor of the present invention is illustrated. The remote telephone control system using the same is formed by a plurality of contactors 15, an input telephone wire 17, a voice system, and a keyboard 18. The remote telephone control system serves to control an electric device 19. The telephone input wire 17 extending from the telephone 16 is connected to a voice system and the keyboard 18. Software process stored in the voice system and the keyboard 18 output of which is transferred to a respective contactor 15. One end of the contactor 15 is connected to an external power and another end thereof is connected the electric device 19, i.e. a terminal customer. As shown in FIG. 4, the signal process about the application of the contactor 15 of the present invention is illustrated. When the telephone 16 receives signals, the process is performed according to steps illustrated in FIG. 4. If it is necessary to remotely control the electric device 19, a password is entered. Then the process illustrated in FIG. 4 is performed step by step. It on means to connect the voice system(as switch K is closed in FIG. 2). After the moveable iron core 6 is induced and moves downward, the movable silver spots 3 are in contact with the static silver spots 5. External current will flow through the stationary copper 4 to conduct to the electric device 19. Thereby, a far distance electric device 19 can be remotely controlled by a telephone. Meanwhile the linkage 9 of the moveable downward with the movement of the so as to actuate the micro switch 10 with the moveable iron core 6 separating from the common contact point 11 of the magnetic coil 7. The magnetic coil 7 disconnects so that signals are collected and transfer to IC circuit 12 and then to circuit 13 so as to replace the function of the magnetic coil 7 to overcome the pressure from the upward resilient force of the spring 8. Thus, the moveable iron core 6 is still induced. If it is desired to turn off the electric device 19, the software will process it as well. The last step will be from voice system and keyboard 18 to output to the contactor 15 and then to the magnetic coil 7 (as switch K disconnects in FIG. 2). The moveable iron core 6 will move upwards by the resilient force of the spring 8, causing movable silver spots 3 to disconnect from static silver spots 5. The contactor 15 is not in operation, and no electric devices 19 is actuated. If a plurality of electric devices 19 are desired to be controlled, it is only necessary to increase the number of contactors. Thereby, various electric devices can be controlled. The noise-free low-power consumption wide voltage range dc and ac contactor of the present invention can be combined to a remote telephone control system (receiving portion) so as to be formed as a control device 20, as shown in FIG. 5. Thereby, it can be inserted into an external device and then the telephone input wire is connected so as to conduct with a telephone wire. Thus, the object of control is achieved. The present invention is thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>In the prior art communication contactors, the magnetic coils are used to attract an iron coil and preventing it from being ejected back during the usage of the communication contactor. The magnetic coil must be kept in actuation, thereby causing the magnetic coil to make noise due to continuous actuation. This prior art consumes larger electric power, meanwhile operating cost is increased. Noise not only makes the background too noisy but also shortens the lifetime of the contactor. Due to the large bulk of communication contactor with high cost and large noise, if it is desired to make a noiseless contactor, the volume will become larger and wires are more and more complicated. Thereby, remote telephone control systems using the prior arts are not used widely. Thereby, the prior art contactor still has many drawbacks and is not a preferred design. Thereby, it is necessary to be improved. For improving the above said defects, the inventor of the present invention has create a new design which can improve the prior art defects. | <SOH> SUMMARY OF THE INVENTION <EOH>Accordingly, the primary object of the present invention is to provide a noise-free low-power consumption wide voltage range dc and ac contactor and remote telephone control system using the same, wherein an iron coil is attracted and a retaining coil is used to replace a magnetic coil. Thereby, noise can be reduced and power consumption is also reduced. The magnetic coil is worked in a short time and work transiently. The voltage used is wide, which includes the following three ranges: 1. A first band is from2V˜120V which is commonly for DC and AC, including DC/AC voltage of 2V, 4V, 6V, 8V, 9V, 12V, 24V, 48V, 65V, 80V, 100V, 110V, 120V, etc. 2. A second band is from 100V to 250V which is commonly for DC and AC, including DC/AC of 100V, 110, 120V, 200V, 220V, 240V, 250V, etc. 3. A third band is from 200V to 480V which is commonly for DC/AC, including DC and AC of 200V, 220V, 240V, 250V, 275V, 380V, 415V, 440, 480V. The present invention can be used widely with a range from 0.1 A to 2000 A DC or AC contactor. Moreover, the present invention is simple, lower noise, lower power consumption, lower cost with a small volume. To achieve above object, the present invention provides a noise-free low-power consumption wide voltage range DC and AC contactor comprising: a housing; an static iron core installed on an inner bottom of the housing; an movable copper installed in an inner top of the housing; each of two ends of the movable copper having a respective movable silver spot; static silver spots being installed below the movable silver spots; two stationary coppers connected to a wall of the housing; each of the stationary coppers being installed with a respective one of the static silver spots; a middle part of the movable copper being connected to a movable iron core; a spring installed between a bottom of the moveable iron core and an inner bottom of the static iron core on the housing; a magnetic coil wound around one leg of the static iron core; a retaining coil wound around another leg of the static iron core; characteristic in that a linkage having one end connected to the moveable iron core; a micro switch connected to another end of the linkage; the micro switch being connected to the magnetic coil, an integrated circuit and the retaining coil; wherein the bottom of the moveable iron core is within longitudinal extents of the magnetic coil and retaining coil. The connector can be used with a telephone, a telephone wire, a voice system, a keyboard and a software program so as to be formed as a remote telephone control system with a simple structure, lower cost and be a multi-functional device. Thereby, it can be used widely. | 20040126 | 20060613 | 20050728 | 58074.0 | 0 | DONOVAN, LINCOLN D | NOISE-FREE LOW-POWER CONSUMPTION WIDE VOLTAGE RANGE DC AND AC CONTACTOR AND REMOTE TELEPHONE CONTROL SYSTEM USING THE SAME | SMALL | 0 | ACCEPTED | 2,004 |
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10,763,410 | ACCEPTED | Tie and shirt combination secured with an elastic band | Provided is a combination of clothing articles packaged for sale. The combination comprises a shirt having a shirt collar and a necktie disposed about the shirt collar. The necktie comprises a length of fabric having first and second ends and at least one fold intermediate the first and second ends. An elastic band passes transversely to the length of fabric within the fold and is sized to be stretchably received about the shirt collar. A clip is engaged with the fabric proximate to the fold. The clip pinches the fabric so as to emulate the appearance of a tie knot. Also provided are methods for packaging a necktie and shirt combination. | 1. A combination of clothing articles packaged for sale, comprising: a shirt having a shirt collar; a necktie disposed about the shirt collar and comprising a length of fabric having first and second ends and at least one fold intermediate the first and second ends; an elastic band passing transversely to the length of fabric within the fold and sized to be stretchably received about the shirt collar; and a clip engaged with the fabric proximate to the fold, the clip pinching the fabric so as to emulate the appearance of a tie knot. 2. The combination of clothing items of claim 1, wherein the elastic band passes continuously within the fold. 3. The combination of clothing items of claim 2, wherein the elastic band is a rubber band. 4. The combination of clothing items of claim 1, wherein the clip is generally U-shaped. 5. The combination of clothing items of claim 4, wherein the clip comprises a horizontal base and two fingers the two fingers being resiliently mounted on opposite sides of the base. 6. The combination of clothing items of claim 5, wherein the base further comprises a reinforcement. 7. A method for packaging a necktie and shirt combination, comprising the steps of: providing a shirt having a shirt collar; providing a necktie comprising a length of fabric having first and second ends; folding the necktie along a line transverse to the length of fabric and intermediate the first and second ends, to create at least one fold; positioning an elastic band within the fold; wrapping the elastic band around the shirt collar; and pinching the necktie at a position proximate to the fold with a clip. 8. The method of claim 7, including the additional step of knotting the tie after the positioning step, wherein the knot defines a channel transverse to the length of the fabric and wherein the elastic band is further disposed within the channel. 9. A method for packaging a necktie and shirt combination, comprising the steps of: providing a shirt having a shirt collar; providing a necktie comprising a length of fabric having first and second ends; knotting the necktie to create a knot with a channel therein, the channel being transverse to the length of fabric; positioning an elastic band within the channel; and wrapping the elastic band around the shirt collar. | FIELD OF THE INVENTION The present invention relates generally to presenting items of clothing and specifically to presenting shirt and tie combinations. BACKGROUND OF THE INVENTION Retailers are discovering that shirt and tie combinations packaged together better meet the needs of a certain class of shoppers. When displaying and selling dress shirts in combination with ties, retailers assist their clients with a fashion choice that can be time consuming. Furthermore, when suitably coordinated, a shirt and a tie combination can make a more attractive display item for sale than if displayed individually. Unfortunately, some consumers tend to remove and replace ties from their previously associated shirt, and thus create additional costs and difficulties to the retailer. Among other problems created, the individual components are not separately priced. Thus, retailers would benefit from a way to package shirt and tie combinations so that the consumer is discouraged from removing ties from these combinations. An existing solution to this problem is to wrap the entire shirt and tie combination in a clear plastic bag. However, this solution proves unsatisfactory for consumers who wish to inspect the material of the shirt or tie by touching it. The present invention provides needed improvements in this field. SUMMARY OF THE INVENTION Provided is a shirt and tie combination. The combination comprises a shirt having a shirt collar and a necktie. The necktie is disposed about the shirt collar. The necktie comprises a length of fabric having first and second ends. A fold is placed between the first and second ends. The combination also comprises an elastic band and a clip. The elastic band is sized to be stretchably received about the shirt collar. It passes transversely to the length of fabric within the fold. The clip is engaged with the fabric proximate to the fold. It pinches the fabric so as to emulate the appearance of a tie knot. In a further aspect of the present invention the elastic band passes continuously through the fold. In yet another aspect the clip is generally U shaped. The clip comprises a base and two fingers extending from opposite ends of the base. Also provided is a method for packaging a necktie and shirt combination. A shirt having a collar is obtained. Also obtained is a necktie comprising a length of fabric having first and second ends. The necktie is folded along a line transverse to the length of fabric and intermediate the first and second ends. Thus, at least one fold is created. The elastic band is positioned within that fold. The elastic band is then wrapped around the shirt collar. The necktie is pinched at a position proximate to the fold with a clip. Also provided is a second method for packaging a necktie and shirt combination. A shirt having a collar is obtained. Also obtained is a necktie comprising a length of fabric having first and second ends. The necktie is knotted to create a knot. A channel is formed inside the knot, the channel being transverse to the length of fabric. The elastic band is positioned within that channel. The elastic band is then wrapped around the shirt collar. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of the shirt and tie combination; FIG. 2 is a side view of the shirt and tie combination as cut along line A-A′; and FIG. 3 is an end plan view of the clip. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a front view of a shirt and tie combination. The shirt 100 is preferably folded as shown. The shirt 100 includes a collar 101. A necktie 102 is also included. The necktie essentially comprises a length of fabric. It may be any suitable fabric such as silk. The necktie may also comprise a combination of fabrics. The fabric of the necktie generally extends in the vertical direction (along line A-A′) as shown in FIG. 1. The necktie has a first end 104 and a second end 105. The necktie 102 is folded between the first and second ends to create a fold 103. The fold is horizontal in FIG. 1, thus being in a direction transverse to that of the fabric of the necktie (namely, transverse to line A-A′). While only a single fold is shown, the necktie may be folded several times in order to achieve desirable length when packaged with the shirt. Furthermore, several folds may be oriented so as to define a knot. An elastic band 106 is placed within the fold, or within at least one of the several folds if several are present. The elastic band 106 is preferably manufactured from rubber, but may be manufactured from an elastic fabric, or a flexible elastic plastic material. The elastic band 106 passes through the fold in a generally horizontal direction, i.e. direction transverse to that in which the necktie extends. The elastic end is resiliently stretched around the collar 101. Preferably, the elastic band is slightly shorter than the circumference of the collar thus necessitating it to be stretched when wrapped around the collar. Preferably, the elastic band passes continuously within the fold. A clip 107 is placed on the necktie in a position proximate to the fold. The clip 107 is preferably placed about 1-1.5 inches below the fold. The clip pinches the necktie in order to create the appearance of a knot, as shown in FIG. 1. If a knot is already present, the clip is not required. FIG. 2 is a side view of the shirt and tie combination as when cut along line A-A′. It is included to provide a more complete depiction of the elements discussed above. The clip is positioned so that the base is between the shirt and the necktie so as to be substantially concealed from view. FIG. 3 is an end plan view of the clip 107. As shown in FIG. 3, the clip is generally U-shaped. It comprises a base 300 and two legs 301 and 302. The legs are resiliently attached to the base at its opposite ends. A reinforcement 303 is also provided. It better prevents the base from breaking. Preferably, the base, the legs and the reinforcement are made from the same resilient material—plastic. Other materials, such as thin metals that are flexible, may be used instead. In use, a necktie and shirt are packaged in combination by providing a shirt having a shirt collar and a necktie. The necktie is folded along a line transverse to the length of its fabric. An elastic band is positioned within the fold and wrapped around the shirt collar. The necktie can then be pinched at a position proximate to the fold with a clip. Alternatively or in addition, the tie can be knotted after the positioning step. In that case, the knot defines a channel transverse to the length of the fabric such that the elastic band can be disposed within the channel. In another packaging method, a shirt is again provided as well as a necktie, with the necktie being knotted to create a knot. The knot is such that it features at least one channel transverse to the length of the fabric. An elastic band is positioned within the channel. The elastic band is wrapped around the shirt collar. The invention has been described in connection with a particular embodiment thereof but is defined solely by the claims appended hereto. | <SOH> BACKGROUND OF THE INVENTION <EOH>Retailers are discovering that shirt and tie combinations packaged together better meet the needs of a certain class of shoppers. When displaying and selling dress shirts in combination with ties, retailers assist their clients with a fashion choice that can be time consuming. Furthermore, when suitably coordinated, a shirt and a tie combination can make a more attractive display item for sale than if displayed individually. Unfortunately, some consumers tend to remove and replace ties from their previously associated shirt, and thus create additional costs and difficulties to the retailer. Among other problems created, the individual components are not separately priced. Thus, retailers would benefit from a way to package shirt and tie combinations so that the consumer is discouraged from removing ties from these combinations. An existing solution to this problem is to wrap the entire shirt and tie combination in a clear plastic bag. However, this solution proves unsatisfactory for consumers who wish to inspect the material of the shirt or tie by touching it. The present invention provides needed improvements in this field. | <SOH> SUMMARY OF THE INVENTION <EOH>Provided is a shirt and tie combination. The combination comprises a shirt having a shirt collar and a necktie. The necktie is disposed about the shirt collar. The necktie comprises a length of fabric having first and second ends. A fold is placed between the first and second ends. The combination also comprises an elastic band and a clip. The elastic band is sized to be stretchably received about the shirt collar. It passes transversely to the length of fabric within the fold. The clip is engaged with the fabric proximate to the fold. It pinches the fabric so as to emulate the appearance of a tie knot. In a further aspect of the present invention the elastic band passes continuously through the fold. In yet another aspect the clip is generally U shaped. The clip comprises a base and two fingers extending from opposite ends of the base. Also provided is a method for packaging a necktie and shirt combination. A shirt having a collar is obtained. Also obtained is a necktie comprising a length of fabric having first and second ends. The necktie is folded along a line transverse to the length of fabric and intermediate the first and second ends. Thus, at least one fold is created. The elastic band is positioned within that fold. The elastic band is then wrapped around the shirt collar. The necktie is pinched at a position proximate to the fold with a clip. Also provided is a second method for packaging a necktie and shirt combination. A shirt having a collar is obtained. Also obtained is a necktie comprising a length of fabric having first and second ends. The necktie is knotted to create a knot. A channel is formed inside the knot, the channel being transverse to the length of fabric. The elastic band is positioned within that channel. The elastic band is then wrapped around the shirt collar. | 20040123 | 20060829 | 20050728 | 97812.0 | 1 | PATEL, TAJASH D | TIE AND SHIRT COMBINATION SECURED WITH AN ELASTIC BAND | SMALL | 0 | ACCEPTED | 2,004 |
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10,763,523 | ACCEPTED | Substrate optical waveguides having fiber-like shape and methods of making the same | Substrate optical wavguides having curved major surfaces and methods for making the same are disclosed. In one exemplary embodiment, a photosensitive cladding layer is pattern exposed to actinic radiation through a first gray-scale mask and subsequently developed to define a groove therein having a curved major bottom surface. A layer of photosensitive core material is thereafter formed over the groove, pattern exposed to actinic radiation through a second gray-scale mask, and subsequently developed to define a core element. The core element is disposed within the groove and has a curved major bottom surface and a curved major top surface. | 1. A method of forming a substrate optical waveguide having a propagation axis along which light is conveyed, a cladding layer, and a core element, the core element having an elongated dimension collinear with the waveguide's propagation axis and a transverse cross-section transverse to the elongated dimension, the method comprising the steps of: (a) forming a lower cladding layer of photosensitive cladding material; (b) exposing the cladding layer to actinic radiation through a first gray-scale mask; (c) developing the exposed pattern to form a groove located in the lower cladding layer and having three-dimensional features; (d) forming a core layer of photosensitive core material over the groove and the remaining portions of the lower cladding layer; (e) exposing the core layer to actinic radiation through a second gray-scale mask; and (f) developing the exposed pattern to form an element of core material located over the groove and having three-dimensional features. 2. The method of claim 1 wherein the photosensitive cladding material is positive type. 3. The method of claim 1 wherein the photosensitive core material is positive type. 4. The method of claim 1 further comprising the step of forming an upper cladding layer over the exposed portions of the core element and lower cladding layer. 5. The method of claim 1 further comprising, after step (c) and prior to step (d), the step of at least partially curing the lower cladding layer. 6. The method of claim 1 further comprising, after step (c) and prior to step (d), the step of reducing the sensitivity of the lower cladding layer to the actinic radiation used in step (e). 7. The method of claim 1 wherein the element of core material has a circular cross-section in a plane transverse to the waveguide's propagation axis. 8. The method of claim 1 wherein the element of core material has an oval-shaped cross-section in a plane transverse to the waveguide's propagation axis. 9. The method of claim 1 wherein the element of core material has top and bottom surface portions which are curved. 10. The method of claim 1 wherein each of the cladding and core materials comprises a common base photosensitive polymer material, and wherein one of the cladding and core materials comprises a minor addition of a different polymer material. 11. A method of forming a substrate optical waveguide having a propagation axis along which light is conveyed, a cladding layer, and a core element, the core element having an elongated dimension collinear with the waveguide's propagation axis and a transverse cross-section transverse to the elongated dimension, the method comprising the steps of: (a) forming a cladding layer of a photosensitive cladding material on a substrate, the solubility of the cladding material in a developer being a function of exposure dosage to actinic radiation; (b) pattern exposing the cladding layer to actinic radiation through a first gray-scale mask, the first gray-scale mask comprising a first area for defining a first segment of the core element, the first area having a length oriented to the propagation axis of the waveguide and a width for initially defining the transverse cross-section of the core element in the first segment, the first area of the first gray-scale mask having a gradation of opacity along its width; (c) thereafter exposing the cladding layer to a developer to form a groove in the layer of photosensitive cladding material, the groove having a first segment with a length disposed along the waveguide's propagation axis and a major curved surface which is curved in a direction transverse to the length of the grooves first segment; (d) forming a core layer of a photosensitive core material over the groove and the cladding layer, the solubility of the core material in a developer being a function of exposure dosage to actinic radiation; (e) pattern exposing the core layer to actinic radiation through a second gray-scale mask, the second gray-scale mask comprising a first area for further defining the first segment of the waveguide's core element, the first area having a length oriented to the propagation axis of the waveguide and a width for further defining the transverse cross-section of the core element in the first segment, the first area of the second gray-scale mask having a gradation of opacity in the direction of its width; and (f) thereafter exposing the core layer to a developer to form the first segment of the waveguide's core element. 12. The method of claim 11, wherein the first gray-scale mask of step (b) further comprises a second area for defining a second segment of the core element, the second area having a length oriented to the propagation axis of the waveguide and a width for initially defining the transverse cross-section of the second segment of the core element, the second area of the first gray-scale mask having a first gradation of opacity along its width and a second gradation of opacity along its length; wherein step (c) of exposing the cladding layer to a developer further forms the groove, with a second segment with a length disposed along the waveguide's propagation axis and a major surface which is curved in a direction transverse to the length of the groove's second segment, the groove's second segment having a gradation in its width and a gradation in its depth; wherein step (d) of forming the core layer further forms the photosensitive core material over the second segment of the groove; wherein the second gray-scale mask of step (e) further comprises a second area for further defining the second segment of the waveguide's core element, the second area having a length oriented to the propagation axis of the waveguide and a width for further defining the transverse cross-section of the core element in the second segment, the second area of the second gray-scale mask having a first gradation of opacity in the direction of its width and a second gradation of opacity along its length; and wherein step (f) of exposing the core layer to a developer further forms the second segment of the waveguide's core element. 13. The method of claim 11, wherein the first gray-scale mask of step (b) further comprises a second area for defining a second segment of the core element, the second area having a length oriented to the propagation axis of the waveguide and a width for initially defining the transverse cross-section of the second segment of the core element, the second area of the first gray-scale mask having a first portion with a first gradation of opacity along its width and a second portion with a radial gradation of opacity about a point; wherein step (c) of exposing the cladding layer to a developer further forms the groove with a second segment with a length disposed along the waveguide's propagation axis and a major surface which is curved in a direction transverse to the length of the groove's second segment, the major surface of the groove's second segment further having a portion which is curved in the direction of the length of the groove's second segment; wherein step (d) of forming the core layer further forms the photosensitive core material over the second segment of the groove; wherein the second gray-scale mask of step (e) further comprises a second area for further defining the second segment of the waveguide's core element, the second area having a length oriented to the propagation axis of the waveguide and a width for further defining the transverse cross-section of the core element in the second segment, the second area of the second gray-scale mask further having a first portion with a gradation of opacity in the direction of the second area's width and a second portion having a circle or oval of constant opacity; and wherein step (f) of exposing the core layer to a developer further forms the second segment of the waveguide's core element. the groove's second segment 14. The method of claim 13 further comprising, between the performance of steps (c) and (d), the step of forming a layer of reflective metal on the bottom surface of the groove's second segment. 15. The method of claim 11 wherein the photosensitive cladding material is positive type. 16. The method of claim 11 wherein the photosensitive core material is positive type. 17. The method of claim 11 further comprising the step of forming an upper cladding layer over the exposed portions of the core element and lower cladding layer. 18. The method of claim 11 further comprising, after step (c) and prior to step (d), the step of at least partially curing the lower cladding layer. 19. The method of claim 11 further comprising, after step (c) and prior to step (d), the step of reducing the sensitivity of the lower cladding layer to the actinic radiation used in step (e). 20. The method of claim 11 wherein the element of core material has a circular cross-section in a plane transverse to the waveguide's propagation axis. 21. The method of claim 11 wherein the element of core material has a circular cross-section in a plane transverse to the waveguide's propagation axis. 22. The method of claim 11 wherein the element of core material has top and bottom surface portions which are curved. 23. The method of claim 11 wherein each of the cladding and core materials comprises a common base photosensitive polymer material, and wherein one of the cladding and core materials comprises a minor addition of a different polymer material. 24. A substrate optical waveguide having a propagation axis along which light is conveyed, said substrate optical waveguide comprising: a lower cladding layer having a top surface, a bottom surface, a first refractive index for light having a first free-space wavelength, and a groove formed in the top surface, the groove having a first segment with a major curved surface and a lowermost depth that lies between the top and bottom surfaces of the lower cladding layer, said lower cladding layer being formed from a photosensitive material such that the lower cladding layer comprises an amount of a photo-active compound and/or an amount of a decomposed photo-active compound; a core element having an elongated dimension collinear with the waveguide's propagation axis and a transverse cross-section transverse to the elongated dimension, said core element having a second refractive index for light having the first free-space wavelength, the second refractive index being different from the first refractive index, the core element further having a first core segment formed in and over the first segment of the groove and having a major top curved surface and a major bottom curved surface, said core element being formed from a photosensitive material such that the core element comprises an amount of a photo-active compound and/or an amount of a decomposed photo-active compound; and an upper cladding layer formed over at least one of the exposed portions of said lower cladding layer and at least one of the exposed portions of said core element. 25. The substrate optical waveguide of claim 24 wherein the core element has a circular cross-section in a plane transverse to the waveguide's propagation axis. 26. The substrate optical waveguide of claim 24 wherein the groove of the lower cladding layer further has a second segment adjacent to the first segment, the second segment of the groove having a major curved surface and a lowermost depth that lies between the top and bottom surfaces of the lower cladding layer, the groove's second segment having a gradation in its width and a gradation in its depth; and wherein the core element further has a second segment formed in and over the second segment of the groove and having a major top curved surface and a major bottom curved surface, the bottom major surface of the core element's second segment having a gradation in its width and a gradation in its depth, the top major surface of the core element's second segment having a gradation in its width and a gradation in its height. 27. The substrate optical waveguide of claim 24 wherein the groove of the lower cladding layer further has a second segment adjacent to the first segment, the second segment of the groove having a major curved surface and a lowermost depth that lies between the top and bottom surfaces of the lower cladding layer, the groove's second segment having a gradation in its width and a gradation in its depth in a form of the lower portion of an elbow-bend; and wherein the core element further has a second segment formed in and over the second segment of the groove and having the form of an elbow-bend. 28. The substrate optical waveguide of claim 24 wherein the groove of the lower cladding layer further has a second segment adjacent to the first segment, the second segment of the groove having a major curved surface and a lowermost depth that lies between the top and bottom surfaces of the lower cladding layer, the groove's second segment having a gradation in its width and a gradation in its depth in a form of the lower portion of an elbow-bend; a layer of metal formed on the surface of the elbo-bend; and wherein the core element further has a second segment formed in and over the second segment of the groove and the layer of metal, the second segment of the core element having the form of an elbow-bend. 29. A substrate optical waveguide having a propagation axis along which light is conveyed, said substrate optical waveguide comprising: a lower cladding layer having a top surface, a bottom surface, a first refractive index for light having a first free-space wavelength, and a groove formed in the top surface, the groove having a first segment with a major curved surface and a lowermost depth that lies between the top and bottom surfaces of the lower cladding layer, and a second segment adjacent to the first segment, the second segment of the groove having a major curved surface and a lowermost depth that lies between the top and bottom surfaces of the lower cladding layer, the groove's second segment having a gradation in its width and a gradation in its depth in a form of the lower portion of an elbow-bend; a core element having an elongated dimension collinear with the waveguide's propagation axis and a transverse cross-section transverse to the elongated dimension, said core element having a second refractive index for light having the first free-space wavelength, the second refractive index being different from the first refractive index, the core element further having a first core segment and a second core segment adjacent to the first core segment, the first core segment being formed in and over the first segment of the groove and having a major top curved surface and a major bottom curved surface, the second core segment being formed in and over the second segment of the groove and having the form of an elbow-bend; and an upper cladding layer formed over at least one of the exposed portions of said lower cladding layer and at least one of the exposed portions of said core element. 30. The substrate optical waveguide of claim 29 wherein the first core segment has a circular cross-section in a plane transverse to the waveguide's propagation axis. | FIELD OF THE INVENTION The present invention relates to optical waveguides formed on planar substrates, such as integrated circuit substrates, and methods of making the same, and more particularly to such optical waveguides having fiber-like shapes. BACKGROUND OF THE INVENTION In the art of planar waveguide circuit substrates, optical waveguides can be formed along with opto-electronic components and/or electrical traces in an effort to reduce signal propagation times across the circuit boards of electronic systems and, in some cases, across integrated circuit chips. As an example, consider an opto-electronic interconnect board intended to electrically connect several integrated-circuit (IC) chips together as a system. There would often be a need in such a system to convey an electrical signal from an IC chip at one end of the board to another IC chip at the opposite end of the board, with a distance of perhaps tens of centimeters between the two IC chips. A conventional electrical signal trace formed in the interconnect board, configured to electrically connect these two IC chips, would have a large amount of resistance and capacitance, and thus would have a large propagation delay. In theory, an optical connection between these two IC chips would not have such a large delay. For such an optical connection, an opto-electric conversion device (e.g., VCSEL or light modulator) may be positioned under one IC chip and electrically connected thereto, another opto-electric conversion device (e.g., photodetector) may be positioned under the other IC chip and electrically connected thereto, and an optical waveguide may be formed between the two opto-electric conversion devices. The optical waveguide comprises a strip of core material, with a square or rectangular transverse cross-section, disposed between two cladding layers. The performance of such substrate optical transmission systems has not met the full desired expectations, and there is a recognition in the art for improvement of these systems. The distance over which signals can be reliably transmitted is less than desired, and the amount of power required to transmit the optical signal is greater than desired. Current research is focused on improving the opto-electric conversion devices, and their integration onto the substrate. The current view in the art is that improvements will address the less-than-desired performance of these systems. SUMMARY OF THE INVENTION As part of making his invention, the inventor has recognized that the cross-sectional shape of the core element of a substrate waveguide is square or rectangular, and he has found that this shape introduces a polarization-dependent loss in the transmission of light through the waveguide. Specifically, the distance from the center of the waveguide to a far corner of the waveguide is significantly larger than the distance from the center to a side (being 1.4 times larger for a square core, and even larger for a rectangular core), and this difference creates a polarization-dependent loss in the transmission of light in the waveguide. The inventor has also recognized that many substrate-waveguide applications require the incorporation of 45-degree mirror structures at the ends of some waveguides in order to direct the light out of the substrate in a vertical direction (in other words, change the propagation direction from being horizontal to the surface to being vertical to the surface). As part of making another aspect of his invention, the inventor has found that mirror structures have optical divergences that introduce additional transmission losses, particularly for rectangular and square cores where the above-noted polarization-loss effects have occurred. The inventor has discovered that these losses can be addressed by replacing the square and rectangular cores with cores having circular or oval-shaped cross-sections, and by using an elbow-bend segment of core material in place of a 45-degree mirror. The present invention is directed to these structures and to methods of making them. Exemplary methods according to the present invention comprise forming a lower cladding layer of photosensitive material, exposing the cladding layer to actinic radiation through a first gray-scale mask instead of a conventional “binary” mask, and developing the exposed pattern to form a groove located in the lower cladding layer and having three-dimensional features. The exemplary methods further comprise forming a core layer of photosensitive material over the groove and the remaining portions of the lower cladding layer, exposing the core layer to actinic radiation through a second gray-scale mask, and developing the exposed pattern to form an element of core material located in and over the groove, and having three-dimensional features. An upper cladding layer may then be formed over the core element and lower cladding layer. Accordingly, it is an object of the present invention to provide waveguide core elements that have three-dimensional features and methods for making the same. It is a further object of the present invention to provide waveguide core elements that have circular or oval-shaped transverse cross-sections and methods for making the same. It is yet another object of the present invention to provide waveguide core elements that have elbow-bend segments and methods for making the same. These and other objects of the present invention will become clear to one of ordinary skill in that art after a review of the present application. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a perspective view of a first waveguide structure according to the present invention. FIGS. 2-9 show views of the first waveguide structure during various stages of fabrication according to the present invention, with FIGS. 4 and 8 showing top plan views of exemplary gray-scale masks according to the present invention. FIG. 10 shows a perspective view of a second waveguide structure according to the present invention. FIG. 11 shows a cross-sectional view of the second waveguide structure shown in FIG. 10 according to the present invention. FIGS. 12 and 13 show top-plan views exemplary gray-scale masks which may be used in the construction of the second waveguide structure shown in FIGS. 10-11 according to the present invention. FIG. 14 shows a first cross-sectional comparison of the first and second exemplary waveguide structures showing grooves according to the present invention. FIG. 15 shows a second cross-sectional comparison of the first and second exemplary waveguide structures showing the three-dimensional penetration depth of actinic radiation through the second sets of gray-scale masks according to the present invention. FIG. 16 shows cross-sections of exemplary waveguide structures having cores with oval transverse cross-sections according to the present invention. FIG. 17 shows an exemplary electronic system incorporating the first and second exemplary waveguide structures according to the present invention. DETAILED DESCRIPTION OF THE INVENTION A first waveguide structure according to the present invention is shown at 10 in FIG. 1. Waveguide structure 10 is formed on a substrate 1 and comprises a lower cladding layer 11, a core element 30 partially embedded in lower cladding layer 11, and an upper cladding layer 20 which covers portions of core element 30. Waveguide structure 10 is generally designed to convey light having a wavelength in the range of approximately 700 nm to approximately 1600 nm (as measured in free space, so called “free-space wavelength”). Cladding layers 11 and 20 are optically transparent or semi-transparent at the desired operating wavelength, and have indices of refraction (n) which are equal or close to one another at the desired operating wavelength. Core element 30 is optically transparent or semi-transparent at the desired operating wavelength, and has an index of refraction which is greater than each of the indices of the cladding layers at the desired operating wavelength (preferably by a value of at least 0.02, preferably by a value of at least 0.05). A greater degree of optical transparency in the core element and cladding layers means that a lower degree of optical absorption occurs, which further means that the waveguide structure can conduct light over a greater distance. However, a high degree of transparency is not required when waveguide structure 10 is used to convey light over short distances. As one exemplary embodiment, core element 30 comprises a first core segment 31 and a second core segment 32 optically coupled to first core segment 31. Each of core segments 31 and 32 has an elongated dimension along which light is to propagate (the “Propagation Axis”), and a circular or oval cross-section in plane that is transverse to the elongated dimension (and transverse to the propagation axis of the light). First core segment 31 has a substantially uniform transverse cross-section along the length of its elongated dimension. For example, in the case of a circular transverse cross-section, first core segment 31 may have a uniform diameter. Also, in the case of an oval transverse cross-section, first core segment 31 may have major and minor axes with substantially constant values along the elongated dimension. In either case, core segment 31 has a major top curved surface and a major bottom curved surface, and a lowermost depth into cladding layer 11 that lies between the top and bottom surfaces of cladding layer 11. Second core segment 32 has a transverse cross-section whose dimensions vary along the length of its elongated dimension. At its coupling point with first core segment 31, second core segment 32 has a cross-section that is substantially the same as that of first core segment 31. However, the dimensions (and area) of the cross-section of second core segment 32 increase along the length of the second core segment 32 as one moves toward the right side face of the device, where core segment 32 exits the substrate. The increase in dimensions causes a flaring in the waveguide core, and this flaring is particularly useful for coupling the waveguide to an optical fiber, which has a core with a large transverse cross-section. The flaring eases the tolerances for alignment of the optical fiber to the waveguide, and increases coupling efficiency. Like core segment 31, core segment 32 has a major top curved surface and a major bottom curved surface, and a lowermost depth into cladding layer 11 that lies between the top and bottom surfaces of cladding layer 11. The terms “lower cladding layer” and “upper cladding layer” used herein indicate that the lower cladding layer is formed before the upper cladding layer; the terms are not intended to imply any specific orientation of the layers during the use of the waveguide structure since one may use the waveguide structure in any orientation. Substrate 1 may comprise a single layer of material, or multiple layers of various materials, and may include such components as electrical traces, electrical vias, embedded electronic components and embedded opto-electronic components. In preferred embodiments, substrate 1 comprises an adhesion layer (sometimes called a coupling layer) immediately adjacent to lower cladding layer 11. The formation of such adhesion layers is well known to the art, and a description thereof is not needed herein for one of ordinary skill in the art to make and use the present invention. FIGS. 2-9 illustrate exemplary methods of constructing waveguide structure 10. Starting with substrate 1, a first cladding layer 11 of a photosensitive cladding material is formed on substrate 1. As is known in the art, photosensitive polymer materials may be provided in the form of sheets of solid material with adhesive on one or both sides, or may be initially provided in a viscous form fluidized by one or more solvents, which can be referred to as the fluidized form of the material. The present invention may be practiced with either form. The fluidized form is currently preferred. Photosensitive polymer sheets may be applied by conventional lamination methods; lamination at reduced atmospheric pressures may be used when laminating onto existing sheets with fine features. After lamination, the photosensitive sheet is pattern exposed to actinic radiation, and then developed by a developer. The fluidized photosensitive polymer materials are usually formed one the substrate by spin coating while in their fluidized form, the process of which achieves a substantially uniform thickness across the substrate. Other coating methods are possible. After coating on the substrate, the layer of fluidized material is soft-baked (heated to a low temperature compared to cure temperature of the material) to drive off the solvents, thereby leaving a solidified layer of the photosensitive material. The photosensitive material is then pattern exposed to actinic radiation, and then developed by a developer. If another fluidized polymer layer is to be subsequently formed over an existing polymer layer, the existing polymer layer is preferably treated to prevent the solvents of the subsequent layer from weakening or dissolving the existing layer. Such treatments are well-known in the art (e.g., partial curing of the layer), and description thereof is not needed to make and use the present invention. The photosensitive cladding material, when in its solid form, is dissolvable in a developer (typically a water-based solution or a solvent different from the fluidizing solvent) at a rate that is a function of its exposure dosage to actinic radiation. There are several photosensitive cladding materials commercially available. Both negative type (also called “negative tone” and “negative image”) and positive type (also called “positive tone” and “positive image”) are available. As is well known in the art, a positive type photosensitive material is initially resistant to dissolving in the developer, but becomes more soluble in the developer solution as its exposure dosage to actinic radiation increases. In contrast, a negative type photosensitive material can initially be dissolved in the developer, but becomes more insoluble as its exposure dosage to actinic radiation increases. In both types, the solubility of the photosensitive material in its developer is a function of exposure dosage to actinic radiation. In the positive type, solubility is directly related to exposure dosage; in the negative type, solubility is inversely related to exposure dosage. As used herein, actinic radiation is any form of energy which initiates the desired change in solubility, and which can be selectively applied to a layer of the material. Typical forms of actinic radiation include ultraviolet light, deep ultraviolet light, electron beams, and X-rays. Ultraviolet light and deep ultraviolet light have wavelengths of less than 500 nm (as measured in free space). Next, as illustrated in FIG. 3, photosensitive cladding layer 1 is exposed to actinic radiation through a gray-scale mask 50 (i.e., cladding layer 11 is patterned exposed to actinic radiation) in order to form a groove in which core element 30 will be later formed. The groove is to have a curved major surface (i.e., the majority of the groove's surface is curved), so that core element 30 will have a curved major bottom surface. For example, the groove may comprise a rounded surface. The curved major surface of the groove is generated by gray-scale mask 50, which has regions of varying opacity to the actinic radiation. The spatial variation in the mask's opacity causes the cladding layer 11 to receive a spatial variation in the dosage of actinic radiation, which in turn causes cladding layer 11 to have a spatial variation in its solubility to the developer. As a result, portions of cladding layer 11 are removed at different rates, and to different depths, the action of which creates a structure with three-dimensional features since there is a significant variation in the thickness of the developed cladding layer. A top plan view of mask 50 is shown in FIG. 4. Mask 50 has a first area 51 with a length oriented to the propagation axis of waveguide structure 10 and a width for initially defining a groove in which first core segment 31 will be built. Mask 50 also has a second area 52 with a length oriented to the propagation axis of waveguide structure 10 and a width for initially defining a groove in which second core segment 32 will be built. Shown within these areas are thinner, solid lines of constant opacity. Each such line goes through points of the mask that have the same value of opacity; a gradation in opacity occurs between adjacent lines. Each of first and second areas 51 and 52 has a gradation of opacity along its width. In a preferred embodiment, photosensitive cladding layer 11 is a positive type, and the opacities of areas 51 and 52 are at their lowest value (least opaque) at the centers of the widths of the areas, and are at their highest value (most opaque) at the ends of the widths, with gradations from the center to the ends, as indicated in FIG. 4. This causes the centers of the widths to receive greater amounts of actinic radiation than the ends, and generally causes the actinic radiation to penetrate more deeply down into the layer at the centers than at the ends. In addition, second area 52 has a secondary gradation in opacity along its length to effect the flare in the height of second core segment 32 (i.e., to cause the groove for core segment 32 to go deeper). In the preferred embodiments using positive type photosensitive material, the opacity of second area 52 decreases as one moves along its length from area 51 to the right edge of the mask. In other words, the left edge of second area 52 has the same opacity values as the right edge of first area 51, and the opacity values of second area 52 decrease as one moves to the right and away from first area 51. Construction of gray-scale masks is well known to the art, and a description thereof is not necessary for one of ordinary skill in the art to make and use the present invention. In addition, for a particular photosensitive material and exposure time that one of ordinary skill in the art may want to use, the ability to select the gradation values of gray-scale mask 50 and to select the actinic radiation power level to achieve a desired patterned structure is well within the ordinary skill in the art in view of the present specification. As one basic approach, one may construct several test versions of areas 51 and 52 on a gray-scale mask, with the test versions having different degrees of minimum opacity, maximum opacity, and gradations of opacity. One may then review the results and interpolate among the results to construct areas 51 and 52 which will have the desired results. Further iterations on this approach are, of course, possible. The construction and analysis of test versions of mask patterns is part of the usual and normal practice of developing a gray-scale mask, and does not involve undue experimentation. As the next step, cladding layer 11 is exposed to a developer to form a groove 15 in which core element 30 will be later built. The result is shown in FIG. 5. Groove 15 has a length disposed along the waveguide's propagation axis, and a surface that is curved in a direction transverse to the groove's length. Groove 15 has two segments 16 and 17 in which core segments 31 and 32, respectively, will be built. Each of core segments 31 and 32 has a major curved surface and a lowermost depth that lies between the top and bottom surfaces of lower cladding layer 11. As an optional step, the developed cladding layer 11 may be partially cured and/or desensitized (such as by exposure to heat and elevated temperatures, or to a chemical agent) to reduce its sensitivity to actinic radiation. This process step will reduce the chances of cladding layer 11 having further changes in solubility when the core material is subsequently formed and exposed to actinic radiation. This process step will usually also reduce the chances of cladding layer 11 being dissolved by any fluidizing solvents of the core layer. If not, an optional treatment step to increase the resistance to the fluidizing solvent(s) may be preformed. As indicated above, such treatment steps are known in the art. Next, as shown in FIG. 6, a core layer 30′ of photosensitive core material is formed over groove 15 and the remaining portion of cladding layer 11. This defines and forms the bottom parts of core segments 31 and 32. The top parts are yet to be defined. Like the cladding material, the core layer is dissolvable in a developer (usually a liquid solution or a solvent different from the fluidizing, if used) at a rate that is a function of exposure dosage to actinic radiation. In preferred embodiments, the material of core layer 30′ is positive type. Next, as shown in FIG. 7, photosensitive core layer 30′ is exposed to actinic radiation through a second gray-scale mask 60 (i.e., core layer 30′ is patterned exposed to actinic radiation) in order to define the top parts of core segments 31 and 32. The top parts are to have curved major surfaces (e.g., rounded surfaces). The curved surfaces are provided by gray-scale mask 60, which has regions of varying opacity to the actinic radiation. The spatial variation in the mask's opacity causes the core layer 30′ to receive a spatial variation in the dosage of actinic radiation, which in turn causes core layer 30′ to have a spatial variation in its solubility to the developer. As a result, portions of core layer 30′ are removed at different rates, and to different depths, which thereby creates a structure with three-dimensional features since there is a significant variation in the thickness of the developed core layer. A top plan view of mask 60 is shown in FIG. 8. Mask 60 has a first area 61 with a length oriented to the propagation axis of waveguide structure 10 and a width for defining the shape of the top part of first core segment 31. Mask 60 also has a second area 62 with a length oriented to the propagation axis of waveguide structure 10 and a width for defining the shape of the top part of second core segment 32. Shown within these areas are thinner, solid lines of constant opacity. Each such line goes through points of the mask that have the same value of opacity; a gradation in opacity occurs between adjacent lines. Each of first and second areas 61 and 62 has a gradation of opacity along its width. In one set of preferred embodiments, photosensitive core layer 30′ is positive type, and the opacity of areas 61 and 62 is at its highest value (most opaque) at the centers of the widths of the areas, and is at its lowest value (least opaque) at the ends of the widths, with gradations from the centers to the ends, as indicated in FIG. 8. This causes the centers of the widths to receive lower amounts of actinic radiation than the ends, and generally causes the actinic radiation to penetrate less deeply down into the layer at the centers than at the ends. This variation in the opacity is opposite to that of the preferred gray-scale mask for cladding layer 11, described above with respect to FIG. 4. Thus, the preferred gray-scale masks shown FIGS. 4 and 8 are substantially complementary to one another in areas 51, 52, 61, and 62. In addition, second area 62 has a secondary gradation in opacity along its length to effect the flare in the height of second core segment 32. In the preferred embodiments using positive type photosensitive material, the opacity of second area 62 increases as one moves along its length from area 61 to the right edge of the mask. In other words, the left edge of second area 62 has the same opacity values as the right edge of first area 61, and the opacity values of second area 62 increase as one moves to the right and away from first area 61. For a particular photo-sensitive material and exposure times that one of ordinary skill in the art may want to use, the ability to select the gradation values of gray-scale mask 60 and to select the actinic radiation power level to achieve a desired patterned structure is well within the ordinary skill in the art in view of the present specification. As one basic approach, one may use the interpolation method outlined above for gray-scale mask 50. As the next step, core layer 30′ is exposed to a developer, the result of which is shown in FIG. 9. The combination pattern exposure and development creates a core element with a circular or oval cross-section, having a curved top major surface and a curved bottom major surface. To complete the waveguide structure, an upper-cladding layer 20 may be formed over core element 30 and the exposed parts of lower cladding layer 11. Upper-cladding layer 20 need not comprise a photo-sensitive material. The entire structure is then fully cured, if so required by the materials. The result of this is shown in FIG. 1. Prior to forming upper cladding layer 20, core element 30 may be partially cured or otherwise to prevent solvents in the fluidized form of cladding layer 20 from partially dissolving core element 30. A photosensitive material, particularly a positive-type photosensitive material, generally comprises a major portion of a non-photosensitive polymer material, and a minor portion of a photo-active compound that provides the material with its photo-sensitivity. The curing step, if used, generally causes the photo-active compound to decompose to a non-photosensitive component, which is referred to herein as a decomposed photo-active compound. The steps mentioned above for desensitizing the photosensitive materials to actinic radiation can also cause the photo-active compound to decompose to a decomposed photo-active compound. In some cases, not all of the photo-active compound is decomposed by a curing step or a desensitizing step. Thus, after the waveguide structure is formed, the lower cladding layer and the core elements may each comprise an amount of the photo-active compound, and/or an amount of the decomposed photo-active compound. The process of defining the waveguide's core element with photosensitive core and lower cladding layers has the following advantages. First, the side walls of the groove and core element can be made more smooth in comparison to the case where these features are defined by an anisotropic etching process using a three-dimensional photoresist layer. For polymer materials, such anisotropic etching processes usually involve the use of an energetic plasma, which can introduce a roughness to the etched surfaces. Such rough surfaces can be sources of light absorption and scattering. In contrast, the development of a pattern exposed photosensitive layer produces a smoother surface, particularly when followed by a soft-baking step. In addition, plasma etching can change the chemical composition of the etch surface and can contaminate portions of the etched surface with by-products of the decomposition of the photoresist mask. This contamination can also create sources of light absorption and scattering. In contrast, the development of a pattern exposed photosensitive layer does not contaminate the side walls with decomposed by-products. A wide variety of photosensitive core and cladding materials are commercially available and/or described in the patent and technical literature, and these may be used in practicing the present invention. In addition, polymer materials not normally considered for use in optical applications may be used, such as photosensitive polyimides conventionally used as intermetallic dielectric layers in integrated-circuit chip and multi-chip module applications, particularly fluorinated polymers (e.g., fluorinated polyimides) which have high degrees of transparency. As one approach to materials selection, one may use a base photosensitive polymer material for one of the cladding and core layers, and a combination of the base polymer material with a minor addition (less than 50% by weight) of a different (but compatible) polymer material for the other one of the cladding and core layers. The different polymer material is selected such that its addition to the base polymer material causes the combined material to have a different index of refraction (either higher or lower) than that of the base polymer material. In general, the index of refraction of a polymer material is related to the density of the material (generally increasing with increasing density). Accordingly, as one option, one may select the additional polymer material to have a different density from that of the base polymer material. The selection of compatible materials to achieve the difference in refractive indices is well within the ordinary skill of the art. As examples, one can use low-loss polymers from the following companies: Nitto Denko (photosensitive polyimide), Hitachi Chemical Co., Ltd. (OPGUIDE and/or OPI Series), NTT Advanced Technology; (the FL-01, CB-M, CB-L fluorinated polyimide systems), and Nippon Steel Chemical (the V-259PH,EH photosensitive epoxy products), A second waveguide structure according to the present invention is shown at 100 in FIG. 10. Waveguide structure 100 is formed on a substrate 1 and comprises a lower cladding layer 11, a core element 130 partially embedded in lower cladding layer 11, and an upper cladding layer 20 which covers the exposed portions of core element 130 and lower cladding layer 11. Core element 130 comprises a first core segment 131 and a second core segment 132 optically coupled to first core segment 131. First core segment 131 may have substantially the same form as that of core segment 31 described above (e.g., a circular or oval-shaped cross-section), except that it is formed more deeply into cladding layer 11. Second core segment 132 comprises an elbow-bend segment, which is a short segment of waveguide similar to that of core segment 131, but with a 90-degree bend in it (e.g., a cylindrical tube with a 90-degree bend). FIG. 11 shows a side view of waveguide structure, showing the locations of core segments 131 and 132 within cladding layer 11. When the radius of curvature of the 90-degree bend is 15 μm or less, there can be a measurable amount of loss for light traveling around the bend. To reduce such loss, a reflective metal layer 135 may be formed on the bottom curved surface of the bend, and shown in FIG. 11. In preferred embodiments, metal film 135 comprises gold. Like waveguide structure 10, waveguide structure 100 is generally designed to convey light having a wavelength in the range of approximately 700 nm to approximately 1600 nm. Waveguides 100 and 10 may be formed together on the same substrate. Waveguide 100 may be formed by the same above-described steps for forming waveguide structure 10, except that different patterns on the gray-scale masks are used, and an extra process step is included to form metal layer 135, if used. For the sake of brevity, the above steps for forming waveguide structure 10 are incorporated herein by reference for the forming of waveguide structure 100. FIG. 12 shows a top plan view of an exemplary gray-scale mask 150 that may be used to pattern cladding layer 11 for forming waveguide structure 100. Mask 150 has a first area 151 with a length oriented to the propagation axis of waveguide structure 100 and a width for initially defining a groove in which first core segment 131 will be built. Mask 150 also has a second area 152 with a length oriented to the propagation axis of waveguide structure 100 and a width for initially defining a groove in which second core segment 132 will be built. Shown within these areas are thinner, solid lines of constant opacity. Each such line goes through points of the mask that have the same value of opacity; a gradation in opacity occurs between adjacent lines. Each of first and second areas 151 and 152 has a gradation of opacity along its width. In preferred embodiments, photosensitive cladding layer 11 is of positive type, and the opacities of areas 151 and 152 are at their lowest value (least opaque) at the centers of the widths of the areas, and are at their highest value (most opaque) at the ends of the widths, with gradations from the center to the ends, as indicated in FIG. 12. This causes the centers of the widths to receive greater amounts of actinic radiation than the ends of the widths, and generally causes the actinic radiation to penetrate more deeply down into the layer at the centers than at the ends. In addition, second area 152 has a secondary gradation in opacity at its right end to effect the bottom rounding of the elbow bend in core segment 132. This gradation is radial in form, as shown by the lines of constant opacity in FIG. 12. In the preferred embodiments using positive type photosensitive material, the opacity of second area 152 decreases as one moves outward from a distal point 153 to the area right of distal point 153, as shown in FIG. 12. FIG. 13 shows a top plan view of an exemplary gray-scale mask 160 that may be used to pattern core layer 30′ in the construction of waveguide structure 100 (core segments 131 and 132 are formed from core layer 30′ ). Mask 160 has a first area 161 with a length oriented to the propagation axis of waveguide structure 100 and a width for defining the shape of the top part of first core segment 131. Mask 160 also has a second area 162 with a length oriented to the propagation axis of waveguide structure 100 and a width for defining the shape of the top part of second core segment 132 (the elbow-bend). Shown within these areas are thinner, solid lines of constant opacity. Each such line goes through points of the mask that have the same value of opacity; a gradation in opacity occurs between adjacent lines. Each of first and second areas 161 and 162 has a gradation of opacity along its width. In preferred embodiments, photosensitive core layer 30′ is positive type, and the opacity of area 161 is at its highest value (most opaque) at the center of its width, and is at its lowest value (least opaque) at the end of its width, with gradations from the center to the end, as indicated in FIG. 12. This causes the center of the width to receive lower amounts of actinic radiation than the ends, and generally causes the actinic radiation to penetrate less deeply into the layer at the centers than at the ends. The variation in the opacity in second area 162 is more complex. The left side of area 162 matches the opacity profile of area 161, with the lines of constant opacity at the left side of area 162 matching those at the right side of area 161. At the right side of area 162, there is a large circle or oval of high opacity, preferably constant opacity, which is for defining the vertical section of core segment 132. The opacity of this circle is higher than the maximum opacity in area 161 used for defining the top of core segment 131. This difference in opacity enables one to create a difference in height between the top end of core segment 132 and the top of core segment 131. Finally, the lines of constant opacity in area 162 flare out as they go from left to right, in order to define the top curved surface of core segment 132. Steps for forming metal layer 135 may be performed at a time after layer 11 has been patterned and before layer 20 is formed. In this case, a photoresist layer is formed over layer 11, and is defined to open a window over the location where metal layer 135 is to be formed. Thereafter, one or more metal layers are sputtered, deposited, or otherwise formed over the masked substrate. Typically, a metal adhesion layer is first formed (e.g., chromium), followed by a reflective metal (e.g., gold). Thereafter the photoresist layer is striped, and the processing continues with the formation steps outlined above for forming layer 20. FIG. 14 shows a side-by-side comparison of the cross-sections of the grooves 16 and 116 formed in cladding layer 11 for core segments 31 and 131, respectively. FIG. 14 shows the cross-sections after cladding layer 11 has been pattern exposed to actinic radiation and subsequently exposed to the developer. As can be seen, groove 116 is deeper than groove 16, and the side walls of groove 116 have portions near the top surface of layer 11 which are substantially vertical, rather than curved. FIG. 15 shows a side-by-side comparison of the cross-sections of waveguide devices 10 and 100 after core layer 30′ has been formed and pattern exposed to actinic radiation through gray-scale masks 60 and 160, respectively. The exposure depth for each of these structures is shown by lines 65 and 165. For waveguide structure 100, the exposure depth penetrates a small distance into cladding layer 11. There may be a loss of the top portion of cladding layer 11 because of this penetration, but the loss will be replaced by the subsequent formation of upper cladding layer 20. Also, the small difference between the indices of refraction for layers 11 and 30′ is not expected to cause an undesired refractive effect during the pattern exposure to actinic radiation. As indicated above, waveguide cores with oval cross-sections as well as circular cross-sections may be formed. FIG. 16 shows two exemplary oval core cross-sections at 30A and 30B. These cross-sections may be readily achieved by the selection of the gradations in gray-scale masks 50, 60, 150, and 160. FIG. 17 shows an interconnect application 200 in which both waveguide structures 10 and 100 may be formed and used together on a substrate 1. Substrate 1 comprises several wiring planes 202 and vertical electrical interconnects 204 that electrically interconnect a plurality of integrated circuit (IC) chips 220. Electrical pads of the chips 220 are electrically coupled to vertical interconnects 204 by respective solder bumps 214. An optical interconnect layer 210 is formed over the top surface of substrate 1, with vertical interconnects 204 being integrally formed into optical interconnect layer 210 in order to pass vertically through the layer. An instance of waveguide structure 10 and three instances of waveguide 100 within optical interconnect layer 210 are shown in FIG. 17. As such, optical interconnect layer comprises a lower cladding layer, an upper cladding layer, and several core elements disposed between the cladding layers. At one of its ends, waveguide structure 10 is optically coupled to an optical fiber 5 through a surface-mount holder 205. At its other end, waveguide structure 10 is optically coupled to an instance of waveguide structure 100, which in turn is optically coupled to a portion of IC chip 220 by a ball of “optical glue.” The portion of the IC chip has an opto-electronic device 225 disposed at the surface of the chip to either receive or transmit an optical signal. Optical glue is well known to the art, and comprises a flexible, clear polymer material which has an index of refraction close to that of the core material. Exact equality in the indices of refraction is not needed since the light travels in a direction which is perpendicular to the junction between the end of waveguide 100 and the ball of optical glue. Also shown are two instances of waveguide 100 which are optically coupled together at their second core segments 132. The other ends of these waveguides are optically couple to portions of the leftmost and right most IC chips 220, through respective balls of optical glue. For receiving an optical signal, opto-electronic device 225 may comprise a photodetector; for transmitting an optical signal, opto-electronic device 225 may comprise a vertical cavity emitting laser (VCSEL). While the present invention has been particularly described with respect to the illustrated embodiments, it will be appreciated that various alterations, modifications and adaptations may be made based on the present disclosure, and are intended to be within the scope of the present invention. While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the present invention is not limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>In the art of planar waveguide circuit substrates, optical waveguides can be formed along with opto-electronic components and/or electrical traces in an effort to reduce signal propagation times across the circuit boards of electronic systems and, in some cases, across integrated circuit chips. As an example, consider an opto-electronic interconnect board intended to electrically connect several integrated-circuit (IC) chips together as a system. There would often be a need in such a system to convey an electrical signal from an IC chip at one end of the board to another IC chip at the opposite end of the board, with a distance of perhaps tens of centimeters between the two IC chips. A conventional electrical signal trace formed in the interconnect board, configured to electrically connect these two IC chips, would have a large amount of resistance and capacitance, and thus would have a large propagation delay. In theory, an optical connection between these two IC chips would not have such a large delay. For such an optical connection, an opto-electric conversion device (e.g., VCSEL or light modulator) may be positioned under one IC chip and electrically connected thereto, another opto-electric conversion device (e.g., photodetector) may be positioned under the other IC chip and electrically connected thereto, and an optical waveguide may be formed between the two opto-electric conversion devices. The optical waveguide comprises a strip of core material, with a square or rectangular transverse cross-section, disposed between two cladding layers. The performance of such substrate optical transmission systems has not met the full desired expectations, and there is a recognition in the art for improvement of these systems. The distance over which signals can be reliably transmitted is less than desired, and the amount of power required to transmit the optical signal is greater than desired. Current research is focused on improving the opto-electric conversion devices, and their integration onto the substrate. The current view in the art is that improvements will address the less-than-desired performance of these systems. | <SOH> SUMMARY OF THE INVENTION <EOH>As part of making his invention, the inventor has recognized that the cross-sectional shape of the core element of a substrate waveguide is square or rectangular, and he has found that this shape introduces a polarization-dependent loss in the transmission of light through the waveguide. Specifically, the distance from the center of the waveguide to a far corner of the waveguide is significantly larger than the distance from the center to a side (being 1.4 times larger for a square core, and even larger for a rectangular core), and this difference creates a polarization-dependent loss in the transmission of light in the waveguide. The inventor has also recognized that many substrate-waveguide applications require the incorporation of 45-degree mirror structures at the ends of some waveguides in order to direct the light out of the substrate in a vertical direction (in other words, change the propagation direction from being horizontal to the surface to being vertical to the surface). As part of making another aspect of his invention, the inventor has found that mirror structures have optical divergences that introduce additional transmission losses, particularly for rectangular and square cores where the above-noted polarization-loss effects have occurred. The inventor has discovered that these losses can be addressed by replacing the square and rectangular cores with cores having circular or oval-shaped cross-sections, and by using an elbow-bend segment of core material in place of a 45-degree mirror. The present invention is directed to these structures and to methods of making them. Exemplary methods according to the present invention comprise forming a lower cladding layer of photosensitive material, exposing the cladding layer to actinic radiation through a first gray-scale mask instead of a conventional “binary” mask, and developing the exposed pattern to form a groove located in the lower cladding layer and having three-dimensional features. The exemplary methods further comprise forming a core layer of photosensitive material over the groove and the remaining portions of the lower cladding layer, exposing the core layer to actinic radiation through a second gray-scale mask, and developing the exposed pattern to form an element of core material located in and over the groove, and having three-dimensional features. An upper cladding layer may then be formed over the core element and lower cladding layer. Accordingly, it is an object of the present invention to provide waveguide core elements that have three-dimensional features and methods for making the same. It is a further object of the present invention to provide waveguide core elements that have circular or oval-shaped transverse cross-sections and methods for making the same. It is yet another object of the present invention to provide waveguide core elements that have elbow-bend segments and methods for making the same. These and other objects of the present invention will become clear to one of ordinary skill in that art after a review of the present application. | 20040123 | 20080212 | 20050728 | 99764.0 | 0 | MCPHERSON, JOHN A | SUBSTRATE OPTICAL WAVEGUIDES HAVING FIBER-LIKE SHAPE AND METHODS OF MAKING THE SAME | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,763,609 | ACCEPTED | Conventional bedding mattress with illumination properties | A conventional bedding mattress is constructed in a manner that permits light to permeate upwardly throughout the bedding components so as to illuminate the entire bed structure when a light source is placed below the mattress proper. The illuminating feature of the bed is accomplished by forming a bed mattress of a spring core section, a translucent netting layer disposed over the spring core, a unique foam padding that freely lays on top of the netting layer, and a material cover that envelopes the core and padding. The cover is provided with a clear plastic bottom portion sewn into the cover. The padding layer is translucent and this same padding is used as a padding layer within the cover. Light freely passes through the plastic of the cover, through the spring cores, then passing through the padding layer and into the cover, thereby illuminating the mattress upon provision of an underlying light source. | 1. A conventional bedding mattress having illumination properties, comprising: an inner core comprising a plurality of identical, interconnected coil springs each having a top and a bottom end, which when interconnected together, form a unitary top, bottom and sides of said mattress; a translucent layer of elastomeric netting superimposed over said top end of said inner core so as to enclose said top ends of said coil springs, said netting secured to said inner core; an unsecured padding layer superimposed over said elastomeric netting layer, wherein said unsecured padding layer permits individual movement of the top ends of the coil springs relative to each other and wherein said padding layer is translucent; and a covering for enclosing said padding layer and said core of springs, said covering comprised of a top and a bottom panel, wherein said bottom panel is a clear vinyl material and said top panel is a fabric, said covering being translucent. 2. The bedding mattress of claim 1, wherein said top part of said covering is enveloped about said top and sides of said core and said bottom part is disposed over said bottom side of said core. 3. The bedding mattress of claim 2, wherein said top part of said covering is comprised of three component layers, said outermost component layer is a fabric material, said intermediate component layer is a second padding layer of the same material as said unsecured padding layer and said bottom component layer is a ticking material. 4. The bedding mattress of claim 1, wherein said netting layer includes a plurality of spaced tabs for securing said netting to said core. 5. The bedding mattress of claim 1, wherein said padding layer is comprised of compressed polyester. 6. The bedding mattress of claim 3, wherein said intermediate component layer is comprised of compressed polyester. 7. The conventional mattress of claim 1, wherein said coil springs of said core are interconnected by securing elements attached to adjacent springs. 8. A method of constructing a conventional bedding mattress having illumination properties, comprising the steps of: providing a core of interconnected coil springs, wherein said core has a top, a bottom, and sides; securing a netting layer on said top of said core; placing a translucent padding layer on top of said netting layer; enveloping a covering about said core, netting layer and padding layer, wherein said covering is translucent. | BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conventional bedding mattress that is constructed with an inner core of springs, a translucent padding layer, and a mattress cover that comprises a transparent vinyl bottom panel attached to a top portion that also contains translucent padding materials. Collectively, this unique combination of translucent materials provides the mattress with illumination properties, whereby when an underlying source of light is placed below the mattress, the entire mattress, including the cover, becomes illuminated in a decorative manner. 2. Discussion of the Prior Art Furniture designers constantly strive to provide new and aesthetically pleasing designs. In this regard, decoratively and/or functionally illuminating all types of furniture and bedding products with external and/or internal lighting sources has been desirous and popular of furniture and bedding manufacturers for years. Therefore, it is well known that many prior art devices, including furniture and bedding, have included external and/or internal lighting sources to either improve the product appearance or to change its functional properties. For example, in U.S. Pat. No. 3,099,398, a lighting mechanism was incorporated internally into a combination tool box and stand as a means to improve its utility. In U.S. Pat. No. 3,908,598, a transparent aquarium is disclosed having a single, extended fluorescent bulb extending across the top wall thereof as a means to improve the light dispersion throughout the transparent enclosure. U.S. Pat. No. 4,951,181 discloses various types of furniture employing the use of light diffusing glass blocks with an interior light source to provide a unique illuminated effect. A table having a light emitting top is disclosed in U.S. Pat. No. 5,605,393. Incorporating the use of lights in bedding furniture has also been very popular. For example, in U.S. Pat. No. 2,290,866, a lighting fixture is provided at the foot end of an ordinary bed on the underside, not to illuminate the mattress, but to provide indirect, low-level lighting of the floor area directly under and alongside the bed, thereby performing a night light function. In U.S. Pat. No. 4,220,984, an illumination device is secured to the underside head end of a water bed to increase the aesthetic pleasure of sleeping on a waterbed. In U.S. Pat. No. 4,742,437, issued to the present inventor, an improved water bed illumination system is disclosed whereby the waterbed frame incorporates an internal light source that upwardly illuminates light through bore holes in the membrane supporting wall, as well as through ports incorporated into the side rails of the frame. The end result is an illuminated water bed membrane and side frame that is very aesthetically pleasing and unique. In U.S. Pat. No. 4,802,066 a unique type of sun bathing bed made from a transparent cloth for supporting the user, incorporates a series of ultraviolet lights on the underside of the cloth to allow a user to enjoy a sweat-free, sun tanning experience. Other prior art disclosures in the bedding field were designed to improve the functionality of the bed, such as U.S. Pat. No. 5,683,169, which teaches the incorporation of fluorescent lights at the tops of the four bed post, or U.S. Pat. No. 6,234,642, which discloses a hospital bed that incorporates a weight-detecting sensor within the mattress to automatically turn on an underside nightlight. Heretofore, none of the prior art disclosures address the concept of trying to illuminate a conventional bedding mattress because one of the greatest limitations associated with such mattresses is that the components comprising the mattress are not transparent. Therefore, they do not lend themselves to being illuminated by a light source like a water bed bladder membrane, which is generally made from a transparent, elastomeric material. With that in mind, it would be ideal to overcome the shortfalls mentioned above by providing a unique conventional bed mattress construction and method for manufacturing the same, whereby a light source provided on the underside of the bed would illuminate upwardly through each of the components comprising the mattress so that an illuminated and aesthetically pleasing conventional mattress is accomplished. SUMMARY OF THE INVENTION It is the primary object of the present invention to provide a conventional bedding mattress with illumination properties. The object is met in the present invention with a conventional mattress comprising an inner core formed of a plurality of identical, interconnected coil springs, a translucent layer of elastomeric netting superimposed over a top end of said inner core so as to enclose said top ends of said coil springs, an unsecured, translucent padding layer superimposed over said elastomeric netting layer, and a covering for enclosing said padding layer and said core of springs. The covering is comprised of a top and a bottom panel, wherein said bottom panel is a clear vinyl material and the top panel is a fabric. The top part of said covering is enveloped about said top and sides of said core and the bottom part is disposed over said bottom side of said core. The top part of said covering is comprised of three component layers, said outermost component layer is a fabric material, said intermediate component layer is a second padding layer of the same material as the unsecured padding layer and said bottom component layer is a ticking material. One of the unique features of the mattress of the invention is that the padding layer is comprised of compressed polyester, as the intermediate component layer of the cover. The compressed polyester fill material is translucent to light, unlike conventional foam padding that is used in almost every mattress sold today. The present invention further comprises a method of constructing a conventional bedding mattress having illumination properties. That method comprises the steps of providing a core of interconnected coil springs, securing a netting layer on said top of said core, placing a translucent padding layer on top of said netting layer, and then enveloping a covering about said core, netting layer and padding layer, wherein said covering contains a translucent padding therein. The features and advantages of the invention will be further understood upon consideration of the following detailed description of an embodiment of the invention taken in conjunction with the drawings, in which: BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a fragment of the conventional mattress having illumination properties in accordance with the present invention. FIG. 2 is an perspective view of the bottom of the mattress of FIG. 1 in accordance with the invention. FIG. 3 is an exploded view of the mattress in accordance with the invention detailing the components comprising the mattress. FIG. 4 is a perspective view of a part of the spring core portion of the mattress of the invention. FIG. 5 is an exploded perspective view of the top panel of the cover layer of the mattress of the invention. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT The invention provides exemplary illuminated mattresses and methods for their construction. FIGS. 1-3 show the conventional mattress 10 in accordance with the invention, said mattress having a generally rectangular configuration that is defined by a top 12, a bottom 14, and two identical long sides 16 and two identical short sides 18. The mattress with illuminating properties is constructed to have a generally rectangular inner core 20 that is comprised of a series of identical coil springs 22 that are interconnected by means of securing elements 30. Each of the coil springs 22 has a top turn 24 which corresponds to a top end, and a bottom turn 26 which corresponds to a bottom end 28. It is preferable to use coil springs where the top and bottom end turns of each spring are relatively larger in diameter than the intermediate turns, although a coil spring in which all of the turns are of the same diameter can also be used. The coil springs 22 preferably have at least two intermediate turns, but it is possible that they have at least one additional turn. Regardless of the type of coil spring that is being employed, it is preferable that the top and bottom turns 24,26, be flat wound. With flat wound turns, this means that the top and bottom end surfaces 25,27, will be planar, with the plane extending perpendicular to the center axis of each spring. As best seen in FIG. 4, the securing elements 30 are attached to and between two like turns of adjacent springs. In one embodiment, which is the preferred method of interconnection, the securing elements may comprise extended coil springs, identified as element 30A, that are wound in between the turns of the springs 22. With this type of securing element, each turn of the extended coil spring is of the same diameter. When that securing elements 30A are incorporated, it is preferable that the coil springs 22 be interconnected through the top and bottom turns 24, 26. However, when using securing elements 30A, it is also possible to interconnect springs 22 through any of the same intermediate turns. Alternatively, the securing elements may comprise hog rings 30B or clips 30C, that interconnect only the top and bottom turns of each coil spring 22 when the coil springs are of the type having larger top and bottom turns. By attaching the individual coil springs to each other, the core 20 will have stability and comfort. In yet another embodiment of the core 20, border rods 34 may also be employed along the sides 16 and 18, adjacent the top ends 24 and the bottom ends 26 in order to further stabilize the core 20 and hence the mattress 10. The border rods 34 may be slid through the insides of each turn of securing elements 30A, and fastened thereto by well-known rings or clips. Alternatively, if securing elements 30B or 30C are used, the border rods 34 may be attached with rings or clips directly to the coil springs 22. According to the invention, a translucent layer of elastomeric netting 40 is superimposed over all of the top turns of inner core 20 so as to enclose said top ends of each coil spring 22, as illustrated best in FIG. 3. (This netting layer 40 would not readily be seen in FIG. 1 because of the complexity of showing a very thin netting layer in conjunction as an overlay with the springs 22, therefore, it was not included in FIG. 1, although it is an integral part of the invention.) Alternatively, the netting may extend downwardly to the very bottom turn of each of the springs 22, or it may only extend partially down, so that it falls somewhere between the top and bottom ends 24,26 of each spring 22. There are a plurality of spaced tabs 42 that are used for loosely securing the netting layer to the core 20. The tabs 42 may be constructed from the same elastomeric material as the netting, or it may be a fabric material that is glued, heat bonded or sewn to the edge of the netting at the appropriate location. The number of tabs 42 that are used are not critical to the invention, as long as the netting layer 40 remains in a secure position relative to the inner core 20. The layer of netting may be formed with any type of pattern to create the netting effect, such as diamonds, squares, rectangles, etc. As FIGS. 1 and 3 clearly show, superimposed over the layer of netting 40 is an unsecured padding layer 50 comprised of a compressed polyester fill material, wherein said compressed polyester fill layer permits the individual, independent compression of the top ends 24 of the coil springs 22 relative to each other, thereby providing comfort to the user. The layer of netting 40 prevents the padding layer 50 from depressing within the interior openings of each of the coil springs 22, thereby providing stability to the padding layer. One of the unique features of the present invention is the use of the compressed polyester fill material. This type of material has cushioning properties very similar to other mattress padding materials such as a polyurethane or latex foam, rebond (a carpet padding material) or a visco-elastic or memory foam, yet unlike those other materials, it is translucent to all types of light. This translucency feature is one of the most important aspects to the present invention having illumination properties. Without use of this material, no conventional mattress can be illuminated from its interior to its exterior. This material has a trade name of Poly-fil®, manufactured by the Fairfield Corporation, of Danbury, Conn., and it is available in thicknesses between 1-6 inches. For purposes of the present invention, it is preferable to use at least a three inch thickness in order to ensure a construction and comfort level that is comparable to the best mattresses on the market. Another important aspect of the present invention lies in the construction of the covering 60 which envelopes and encloses the padding layer 50, the netting layer 40, and the inner core 20. As should be appreciated when viewing FIG. 1, when inserted over the other internal components, cover 60 holds the coil springs 22 of core 20 together to prevent or substantially reduce their lateral movement, thereby providing mattress 10 with greater stability. As FIGS. 1 and 3 illustrate, covering 60 is comprised of two sections, a top panel 62 and a bottom panel 90 that are attached together. The bottom panel 90 is a pliable, clear vinyl material that is completely light translucent and which extends along the bottom of core 20, substantially within all of the sides 16 and 18, as best seen when viewing FIG. 2. The bottom panel 90 is not directly attached to the core 20, but rather is attached to the top panel 62 by sewing, gluing, or heat bonding. The peripheral edge 92 of panel 90 is preferably sewn to a corresponding peripheral edge 64 on top panel 62. By incorporating a vinyl bottom panel 90 on the underneath side of mattress 10, any light source placed underneath the mattress 10 will illuminate upwardly through the coil springs 22 and further on through the netting layer 40 and padding layer 50 to the top panel 62 of cover 60. Turning to FIG. 5, it is seen that top panel 62 is comprised of three component layers and it provides additional padding to the user and serves as the sleeping surface for mattress 10. The outermost component layer 66 is a quilted layer that is visible to the user with a visible pattern sewn therein. This outer layer 66 is constructed from typical materials that are used in the industry, such as nylon, Dacron, polyester, or a combination of these. The bottom component layer 70 is comprised of a loosely stitched material such as cotton or nylon and it is commonly known in the industry as ticking. Layer 70 is relatively thin compared to the layers 66 or 68 and may be optionally provided. The intermediate component layer 68 is a second padding layer that may be provided in the form of a continuous sheet of material or it may be in the form of loose fill. This layer is comprised of the same compressed polyester fillfillfiber material that was used to form padding layer 50. The three layers 66,68, and 70 are preferably connected by sewing them together to form the unitary top panel 62, with the sewing function leaving the decorative patterns in the outer layer material. Optionally, the top panel 62 may be comprised of only the layers 66 and 68. As seen in the drawing figures, the top panel extends downwardly along the sides of inner core 20 and actually wraps around the very bottom turn 26 of the array of coil springs 22. As mentioned above, the ends of top panel 62 are then attached to bottom panel 90. Because the intermediate component layer 68 is a translucent layer just like padding layer 50, any light source that is placed underneath mattress 10 will project upwardly first through the clear vinyl panel 64, then internally of mattress 10, through the core 20, netting layer 40, padding layer 50, and finally through the intermediate layer 68 to illuminate the very top layer 66. If the intermediate layer did not utilize the compressed polyester fillfillmaterial, the illumination effect of mattress 10 would not be accomplished. Therefore, it is just as critical to the illumination effect of the invention as are the clear vinyl bottom panel, and the translucent netting and padding layers, 40 and 50. While the apparatus and methods described herein form a preferred embodiment of this invention, it will be understood that this invention is not so limited, and changes can be made without departing from the scope and spirit of this invention, which is defined in the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to a conventional bedding mattress that is constructed with an inner core of springs, a translucent padding layer, and a mattress cover that comprises a transparent vinyl bottom panel attached to a top portion that also contains translucent padding materials. Collectively, this unique combination of translucent materials provides the mattress with illumination properties, whereby when an underlying source of light is placed below the mattress, the entire mattress, including the cover, becomes illuminated in a decorative manner. 2. Discussion of the Prior Art Furniture designers constantly strive to provide new and aesthetically pleasing designs. In this regard, decoratively and/or functionally illuminating all types of furniture and bedding products with external and/or internal lighting sources has been desirous and popular of furniture and bedding manufacturers for years. Therefore, it is well known that many prior art devices, including furniture and bedding, have included external and/or internal lighting sources to either improve the product appearance or to change its functional properties. For example, in U.S. Pat. No. 3,099,398, a lighting mechanism was incorporated internally into a combination tool box and stand as a means to improve its utility. In U.S. Pat. No. 3,908,598, a transparent aquarium is disclosed having a single, extended fluorescent bulb extending across the top wall thereof as a means to improve the light dispersion throughout the transparent enclosure. U.S. Pat. No. 4,951,181 discloses various types of furniture employing the use of light diffusing glass blocks with an interior light source to provide a unique illuminated effect. A table having a light emitting top is disclosed in U.S. Pat. No. 5,605,393. Incorporating the use of lights in bedding furniture has also been very popular. For example, in U.S. Pat. No. 2,290,866, a lighting fixture is provided at the foot end of an ordinary bed on the underside, not to illuminate the mattress, but to provide indirect, low-level lighting of the floor area directly under and alongside the bed, thereby performing a night light function. In U.S. Pat. No. 4,220,984, an illumination device is secured to the underside head end of a water bed to increase the aesthetic pleasure of sleeping on a waterbed. In U.S. Pat. No. 4,742,437, issued to the present inventor, an improved water bed illumination system is disclosed whereby the waterbed frame incorporates an internal light source that upwardly illuminates light through bore holes in the membrane supporting wall, as well as through ports incorporated into the side rails of the frame. The end result is an illuminated water bed membrane and side frame that is very aesthetically pleasing and unique. In U.S. Pat. No. 4,802,066 a unique type of sun bathing bed made from a transparent cloth for supporting the user, incorporates a series of ultraviolet lights on the underside of the cloth to allow a user to enjoy a sweat-free, sun tanning experience. Other prior art disclosures in the bedding field were designed to improve the functionality of the bed, such as U.S. Pat. No. 5,683,169, which teaches the incorporation of fluorescent lights at the tops of the four bed post, or U.S. Pat. No. 6,234,642, which discloses a hospital bed that incorporates a weight-detecting sensor within the mattress to automatically turn on an underside nightlight. Heretofore, none of the prior art disclosures address the concept of trying to illuminate a conventional bedding mattress because one of the greatest limitations associated with such mattresses is that the components comprising the mattress are not transparent. Therefore, they do not lend themselves to being illuminated by a light source like a water bed bladder membrane, which is generally made from a transparent, elastomeric material. With that in mind, it would be ideal to overcome the shortfalls mentioned above by providing a unique conventional bed mattress construction and method for manufacturing the same, whereby a light source provided on the underside of the bed would illuminate upwardly through each of the components comprising the mattress so that an illuminated and aesthetically pleasing conventional mattress is accomplished. | <SOH> SUMMARY OF THE INVENTION <EOH>It is the primary object of the present invention to provide a conventional bedding mattress with illumination properties. The object is met in the present invention with a conventional mattress comprising an inner core formed of a plurality of identical, interconnected coil springs, a translucent layer of elastomeric netting superimposed over a top end of said inner core so as to enclose said top ends of said coil springs, an unsecured, translucent padding layer superimposed over said elastomeric netting layer, and a covering for enclosing said padding layer and said core of springs. The covering is comprised of a top and a bottom panel, wherein said bottom panel is a clear vinyl material and the top panel is a fabric. The top part of said covering is enveloped about said top and sides of said core and the bottom part is disposed over said bottom side of said core. The top part of said covering is comprised of three component layers, said outermost component layer is a fabric material, said intermediate component layer is a second padding layer of the same material as the unsecured padding layer and said bottom component layer is a ticking material. One of the unique features of the mattress of the invention is that the padding layer is comprised of compressed polyester, as the intermediate component layer of the cover. The compressed polyester fill material is translucent to light, unlike conventional foam padding that is used in almost every mattress sold today. The present invention further comprises a method of constructing a conventional bedding mattress having illumination properties. That method comprises the steps of providing a core of interconnected coil springs, securing a netting layer on said top of said core, placing a translucent padding layer on top of said netting layer, and then enveloping a covering about said core, netting layer and padding layer, wherein said covering contains a translucent padding therein. The features and advantages of the invention will be further understood upon consideration of the following detailed description of an embodiment of the invention taken in conjunction with the drawings, in which: | 20040123 | 20060718 | 20050728 | 81818.0 | 0 | CONLEY, FREDRICK C | CONVENTIONAL BEDDING MATTRESS WITH ILLUMINATION PROPERTIES | SMALL | 0 | ACCEPTED | 2,004 |
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10,763,726 | ACCEPTED | FOOD CONTAINER | The present description relates to a food container which comprises at least one opening through which food is moved and a humidity source in fluid contact with an air stream providing humidity to the air stream. The air stream is directed across the opening to form a barrier between the interior of the container and the exterior environment. | 1-18. (canceled) 19. A container comprising: at least one opening through which items are moved between the interior and the exterior of the container; and a duct system configured to direct an air stream across the opening, the duct system comprising a plurality of air returns; wherein at least one of the air returns is positioned adjacent to the opening and receives at least a portion of the air stream, the portion of the air stream forming a barrier between the interior of the container and the exterior environment; and wherein the items are configured to be positioned substantially between at least another one of the air returns and the opening, the another one of the air returns being configured to receive another portion of the air stream. 20. The container according to claim 19, wherein the container is portable. 21. The container according to claim 19, comprising a control system configured to control the temperature and/or humidity of the interior of the container. 22. The container according to claim 21, wherein the another portion of the air stream is used to maintain the temperature and/or humidity substantially constant. 23. The container according to claim 19, wherein the items comprise food. 24. A container comprising: at least one opening through which items are moved out of the container; an air curtain provided over the opening to form a barrier between an interior environment of the container and an exterior environment; and a first side positioned substantially opposite the opening, the first side comprising at least one air return which is configured to receive a portion of the air from the air curtain. 25. The container according to claim 24, wherein the items comprise food. 26. The container according to claim 24, comprising a fan configured to circulate the air in the air curtain through the container. 27. The container according to claim 24, wherein the first side is substantially uniformly perforated. 28. The container according to claim 27, wherein the first side is substantially planar. 29. The container according to claim 24, comprising a control system configured to control the temperature and/or humidity of the interior of the container. 30-41. (canceled) 42. The container according to claim 19, comprising a fan which is used to move the air stream through the duct system. 43. The container according to claim 19, wherein the another one of the air returns is positioned on a side of the container which is at least substantially opposite the opening. 44. The container according to claim 19, comprising a water source which is used to humidify the air stream. 45. The container according to claim 19, comprising a control system which is used to control the humidity of the interior of the container. 46. The container according to claim 19, comprising a baffle positioned in the duct system. 47. The container according to claim 46, wherein the air stream passes through the baffle. 48. The container according to claim 46, wherein the baffle is positioned adjacent to a water source which is used to humidify the air stream. 49. The container according to claim 19, wherein the air stream is heated. 50. The container according to claim 24, wherein the items are positioned substantially between the at least one air return and the opening. 51. The container according to claim 24, comprising a water source which is used to humidify the air in the air curtain. 52. The container according to claim 24, comprising a control system which is used to control the humidity of the interior environment of the container. 53. The container according to claim 24, comprising a duct system through which the air in the air curtain moves and a baffle positioned in the duct system. 54. The container according to claim 53, wherein the air in the air curtain passes through the baffle. 55. The container according to claim 53, wherein the baffle is positioned adjacent to a water source which is used to humidify the air in the air curtain. 56. The container according to claim 24, wherein the air in the air curtain is heated. | BACKGROUND The subject matter described herein relates generally to the field of containers. In particular, the subject matter described herein relates to food containers. The food containers may be used for storing food, holding food at temperature, cooling food, humidifying food, rethermalizing food, warming food, and/or cooking food. A wide variety and configuration of food containers are used to house and display food in places such as convenience stores, restaurants, etc. Depending on the type of food, these containers may be heated, cooled, and/or humidified to prevent the food from becoming cold and/or hard, thus making the food more appealing to consumers. For example, the containers may be used to house and display donuts, pastries, hot dogs, etc. In other applications, the containers may be used to refrigerate and/or freeze food to prevent it from melting, spoiling, etc. In still other applications, the containers may be used to hold food at elevated temperature or to cook food. Typically, a solid barrier such as a door is used to isolate the interior of the container from the exterior environment. The door prevents the transfer of heat and/or humidity between the interior of the container and the exterior environment. The door is usually hinged on one side so that it can be opened and closed to provide access to the interior of the container. Unfortunately continually opening and closing the door may result in a loss of productivity and efficiency on the part of the persons using the containers. Users often desire to quickly remove items from the containers. For example, in a fast food setting, a food preparer may want to be able to quickly access food components (e.g., hot dog buns, hot dogs) to prepare the finished food product (e.g., a hot dog in the bun with desired toppings). In other situations, the container may be provided with an opening that does not include a barrier between the exterior environment and the interior of the container. This arrangement results in a loss of efficiency due to excess heating, cooling, and or humidifying. Accordingly, it would be desirable to provide an improved food container for housing items such as food. It should be understood that the claims define the scope of the subject matter for which protection is sought, regardless of whether any of the aforementioned disadvantages are overcome by the subject matter covered by the claims. Also, the terms recited in the claims should be given their ordinary and customary meaning as would be recognized by those of skill in the art, except, to the extent a term is used herein in a manner more expansive than its ordinary and customary meaning, the term should be given its ordinary and customary meaning plus the additional expansive meaning, or except if a term has been explicitly defined to have a different meaning by reciting the term followed by the phase “as used herein shall mean” or similar language. Accordingly, the claims are not tied to any particular embodiment, feature, or combination of features other than those explicitly recited in the claims. SUMMARY One embodiment relates to a food container which comprises at least one opening through which food is moved and a humidity source in fluid contact with an air stream providing humidity to the air stream. The air stream is directed across the opening to form a barrier between the interior of the container and the exterior environment. Another embodiment relates to a food container which defines at least one opening through which food is moved. An air curtain system provides a humidified air curtain over the opening. Another embodiment relates to a container comprising a heating element disposed in the container, at least one opening through which food is moved between the interior and exterior of the Container, and at least one duct configured to direct an air stream across the opening to form a barrier between the interior of the container and the exterior environment. The heating element is used to at least one of cook food, rethermalize food, and maintain food at a temperature. Another embodiment relates to a container comprising at least one opening through which items are moved between the interior and the exterior of the container, a support surface in the container for supporting the items, and an air curtain system providing an air curtain over the opening. A portion of the air stream flowing over and around the items. Another embodiment relates to a container comprising at least one opening through which items are moved between the interior and the exterior of the container and a duct system configured to direct an air stream across the opening, the duct system comprising a plurality of air returns. At least one of the air returns is positioned adjacent to the opening and receives at least a portion of air stream. The portion of the air stream forming a barrier between the interior of the container and the exterior environment. The items are configured to be positioned substantially between at least another one of the air returns and the opening. The another one of the air returns being configured to receive another portion of the air stream. Another embodiment relates to a container comprising at least one opening through which items are moved out of the container, an air curtain provided over the opening to form a barrier between an interior environment of the container and an exterior environment, and a first side positioned substantially opposite the opening. The first side comprising at least one air return which is configured to receive a portion of the air from the air curtain. Another embodiment relates to a container comprising at least one opening through which items are moved between the interior and exterior of the container and an air curtain provided over the opening to form a barrier between the interior of the container and the exterior environment. The air in the air curtain is used to maintain the temperature and the humidity of the interior of the container at substantially controlled levels. Another embodiment relates to a container configured to house food comprising at least one fan configured to output an air stream and a baffle configured to receive the air stream from the fan. The air stream from the baffle passes over a water source to humidify the air stream. The humidified air stream is circulated in the container to maintain the water content of the food at or above a set level. DRAWINGS FIG. 1 is a top perspective view of a container according to one embodiment. FIG. 2 is a front elevation view of the container from FIG. 1. FIG. 3 is a side elevation view of the container from FIG. 1. FIG. 4 is a cross-sectional side view of the container from FIG. 2 along line 4-4. FIG. 5 is a cross-sectional front view of the container from FIG. 3 along line 5-5. FIG. 6 is a top perspective view of the container from FIG. 1 with the outside covers removed. FIG. 7 is a top perspective view of the container from FIG. 6 with additional covers removed. FIG. 8 is a cross-sectional side view of a container according to another embodiment. FIG. 9 is a cross-sectional side view of a container according to another embodiment. DESCRIPTION FIGS. 1, 2, and 3 show a top perspective, front perspective, and side elevation views, respectively, of a container 50 according to one embodiment. Container 50 comprises an interior chamber 52, which is configured to house items such as food in a controlled environment. Container 50 shown in FIGS. 1-9 is shaped similarly to a box with an opening 54 on one side for moving food between the interior and the exterior of container 50. In other embodiments, container 50 may be any of a number of suitable shapes and configurations. For example, container 50 may be substantially cylindrical, etc. Also, container 50 may be configured to be portable (e.g., moved by hand, rolled on castors, etc.) or fixed in a stationary position using a suitable fastening mechanism (e.g., welding, bolted, glued, etc.). In the embodiment shown in FIGS. 1-9, container 50 is configured to be placed on top of a countertop or table. In another embodiment, opening 54 may be located on a top side of container 50. In still another embodiment, container 50 may comprise two, three, or more openings 54 for moving food between the interior and the exterior of container 50. In yet another embodiment, container 50 may comprise transparent sides (e.g., glass, plastic, etc.) so that the food is visible. In one embodiment, container 50 comprises a control system, which is used to maintain the physical characteristics (e.g., temperature, humidity, etc.) of the air in chamber 52 substantially constant. The control system is typically configured to control both temperature and humidity of the air in chamber 52. However, in other embodiments, the control system may be configured to control only one of the temperature and humidity of the air in chamber 52 or may be configured to control additional properties of the air in chamber 52 such as the air's speed. In general, the control system includes any of the components, structure, and matter that is used to control the temperature and humidity of the air in container 50. In one embodiment, the control system comprises at least a thermometer and/or a hygrometer. In another embodiment, the control system comprises a thermostat and/or a humidistat which are used to control the temperature and/or humidity, respectively, of the air in chamber 52. In still another embodiment, the control system may comprise infinite controls for controlling the temperature and/or humidity of the air in chamber 52. Control panel 60 may be used to provide input (e.g., set levels for temperature, humidity, etc.) to the control system. In one embodiment, as shown in FIGS. 1-3, control panel 60 comprises buttons 62 and display 64. Buttons 62 may be used to input the desired temperature and/or humidity level. Display 64 is configured to show the user the set and/or actual temperature and/or humidity levels. In addition, container 50 also comprises a power on/off switch 66 and a power cord 68. In other embodiments, control panel 60 may comprise other input devices and/or displays. For example, control panel 60 may comprise rotary dials instead of buttons 62. Also, control panel 60 may be distributed on container 50. For example, display 64 may be located on one side of container 50 and buttons 62 may be located on another side of container 50. In yet another embodiment, container 50 may be supplied with a computer interface for interfacing with a computerized control system or a computerized information source. As mentioned previously, container 50 defines at least one opening 54 through which food may be moved between the interior and the exterior of container 50. Opening 54 may be any suitable size and shape. In the embodiment shown in FIGS. 1-3, opening 54 is quadrilateral and substantially planar. Opening 54 may be positioned in a substantially vertical plane, as shown in FIGS. 1-3, or may be positioned in a number of other planes (e.g., a substantially horizontal plane for a container where opening 54 is on a top side or a plane at any degree of inclination between a horizontal plane and a vertical plane). In the embodiment shown in FIGS. 1 and 2, trays 56 are used to support food (e.g., pastries, brownies, hot dogs, etc.). Trays 56 are of a sufficient size to pass through opening 54 and be received by rails 70 in chamber 52. In other embodiments, food may be moved between the interior and the exterior of container 50 in a variety of other suitable ways (e.g., individual food items placed in container 50 without using trays 56, etc.). Container 50 uses an air curtain 58 to form a barrier between interior 52 of container 50 and the exterior environment. A user can easily reach through, or otherwise pierce, air current 58 to move food between the interior and the exterior of container 50. Thus, air curtain 58 provides an effective barrier between chamber 52 and the exterior environment yet eliminates the need for the user to open a door while moving food into and out of container 50. Air curtain 58 may also provide an effective barrier against insects and other foreign matter that may otherwise enter chamber 52. Also, a portion of the air from air curtain 58 may be used to humidify, cool, and/or heat the interior of container 50. Referring to FIG. 4, a cross-sectional side view of container 50 along line 4-4 in FIG. 2 is shown. Container 50 comprises at least one fan 74 and a duct system 76 which are configured to circulate air stream 72 through container 50. In general, fans 74 are electrically operated and are configured to provide a constant air flow rate. In another embodiment, fans 74 may be adjustable to provide varying controlled (actively or passively) air flow rates. Fans 74 are provided with outside ventilation using louvers 90, which allow air to enter a ventilation space 92. Air that enters louvers 90 may be used to prevent fans 74 from overheating. Ambient air that enters louvers 90 is kept separate from air stream 72. In another embodiment, air stream 72 may comprise ambient air that is continually being combined with circulated air. In another embodiment, air stream 72 may comprise only ambient air that is brought in through a vent then expelled back into the ambient environment after it has been used to create air curtain 58. In FIG. 4, the general flow of an air stream 72 is shown. As shown in FIGS. 4, 6, and 7, fans 74 blow air into a baffle box 78. Baffle box 78 is a substantially enclosed box comprising a baffle 80 through which air stream 72 is forced to pass. Before passing through baffle 80, air stream 72 may be heated using heating element 82. In other embodiments, heating element 82 may be located in any suitable position in duct system 76. After being heated, air stream 72 passes through baffle 80. In the embodiment shown in FIGS. 4, 6, and 7, baffle 80 comprises a perforated, substantially planar, plate. Typically, the perforations in baffle 80 are also substantially uniform. As air stream 72 passes through the perforations in baffle 80, the velocity of air stream 72 increases briefly before slowing down on the other side of baffle 80. Also, baffle 80 provides a pressure drop. After passing through baffle 80, air stream 72 passes over water source 84 to humidify air stream 72. Once air stream 72 exits baffle 80 the velocity of air stream 72 decreases substantially. The decrease in velocity of air stream 72 and/or the pressure drop across baffle 80 allows air stream 72 to pick up water from water source 84 better than if baffle 80 was not present. Water source 84 comprises a heating element 86 which can be used to heat the water and provide a controlled amount of water vapor to be picked up by air stream 72. Water source 84 is filled using water input 86. Water placed in water input 86 passes through water tube 88 to water source 84. In another embodiment, water source 84 may be coupled to a continuous water supply that refills water source 84 when it gets low (e.g., a float with a valve that turns on when the water level of water source 84 is low). In other embodiments, container 50 may be configured without a water source 84 or any system for humidifying air stream 72. This may be desirable in connection with foods that do not need to be humidified. After passing over water source 84, air stream 72 travels through duct 96, which is a part of duct system 76. As air stream 72 enters duct 96, the velocity of air stream 72 increases due to the smaller area through which air stream 72 now passes. Air stream 72 exits duct 96 through nozzles 94, which are positioned adjacent opening 54 in a downward direction. As air stream 72 passes downward over opening 54, air curtain 58 is created. Air from air curtain 58 returns back to fans 74 through a plurality of air returns 98 in duct system 76. At least one of air returns 98 is positioned adjacent to opening 54 opposite nozzles 94. Air returns 98 positioned opposite nozzles 94 receive a portion of air stream 72 that exits nozzles 94. This portion typically includes most of air stream 72. At least one of air returns 98 is positioned on a first side 100 of chamber 52. Generally, first side 100 is positioned opposite opening 54. Food placed in trays 56 is positioned substantially between air returns 98 positioned on first side 100 and opening 54. A portion of air stream 72 passes over and/or around the food before entering air returns 98 positioned on first side 100. Thus, the water content of the food, temperature and/or humidity of the air in chamber 52 may be controlled using air from air stream 72. In one embodiment, the air from air stream 72 is used to maintain the temperature and/or humidity of chamber 52 substantially constant without the use of additional temperature and/or humidity control systems. As shown in FIGS. 2 and 5, first side 100 is perforated according to a substantially uniform pattern to provide a plurality of distributed air returns 98. In one embodiment, the size of the perforations is between approximately 3 millimeters and approximately 10 millimeters or, desirably, between approximately 5 millimeters and approximately 8 millimeters. In still another embodiment, first side 100 is configured to include a higher density of air returns 98 and/or all of air returns 98 near trays 56. This allows the portion of air stream 72 that passes through the air returns on first side 100 to be nearer to the food, thus enhancing the heat transfer and/or humidification of the food. In other embodiments, first side 100 may comprise a single air return 98 located in any suitable position. After air stream 72 passes through air returns 98, air stream 72 travels through duct system 76 back to fans 74 to begin the cycle again. Referring to FIG. 5, a cross-sectional front view of container 50 along line 5-5 in FIG. 3 is shown. Duct system 76 comprises two separate ducts 102 and 104 through which air is returned from chamber 52 to fans 74. Also, each fan 74 has separate outlet ducts 106 and 108. In other embodiments, duct system 76 may comprise a single duct to circulate air stream 72 through container 50. In still other embodiments, duct system 76 may comprise a filter to capture any particles that may dislodge from the food as it is passed through air curtain 58. Referring to FIGS. 6 and 7, a top perspective view of container 50 with the outside covers removed is shown. FIGS. 6 and 7 provide a top perspective view of fans 74, baffle box 78, baffles 80, ducts 96, and wiring enclosure 110. Wiring enclosure 110 houses electrical wires that provide power to heating elements 82 as well as other electrical devices. FIG. 7 shows container 50 with one of baffle boxes 78 removed. Underneath baffle boxes 78 are covers 112, which cover water source 84. Covers 112 help to isolate water source 84 from heating elements 82. Air stream 72 exits fan outlet ducts 106 and 108, travels through baffle boxes 78 and into ducts 96. Referring to FIG. 8, a cross-sectional side view of container 50 is shown according to another embodiment. In this embodiment, fan 74, baffle 80, and water source 84 are located at the bottom of container 50. Fan 74 is configured to circulate air through container 50 in a manner similar to the previous embodiments. However, in this embodiment, the air in air curtain 58 flows upward from nozzles 94 to air returns 98. In FIG. 9, a cross-sectional side view of container 50 is shown according to another embodiment. In this embodiment, a top side 114 of container 50 comprises opening 54. Accordingly, air curtain 58 is substantially horizontal and provides a barrier between chamber 52 and the exterior environment. The majority of the air from air curtain 58 is received by one or more air returns 98 positioned adjacent to opening 54 and opposite nozzles 94 while the remainder is received by air returns 98 positioned in a bottom side 116 of container 50. This embodiment may also include any other features described or discussed in relation to other previous embodiments. The construction and arrangement of the elements described herein are illustrative only. Although only a few embodiments have been described in detail in this disclosure, those of ordinary skill who review this disclosure will readily appreciate that many modifications are possible without materially departing from the novel teachings and advantages of the subject matter recited in the claims. Accordingly, all such modifications are intended to be included within the scope of the methods and systems described herein. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the embodiments without departing from the spirit and scope of the methods and systems described herein. | <SOH> BACKGROUND <EOH>The subject matter described herein relates generally to the field of containers. In particular, the subject matter described herein relates to food containers. The food containers may be used for storing food, holding food at temperature, cooling food, humidifying food, rethermalizing food, warming food, and/or cooking food. A wide variety and configuration of food containers are used to house and display food in places such as convenience stores, restaurants, etc. Depending on the type of food, these containers may be heated, cooled, and/or humidified to prevent the food from becoming cold and/or hard, thus making the food more appealing to consumers. For example, the containers may be used to house and display donuts, pastries, hot dogs, etc. In other applications, the containers may be used to refrigerate and/or freeze food to prevent it from melting, spoiling, etc. In still other applications, the containers may be used to hold food at elevated temperature or to cook food. Typically, a solid barrier such as a door is used to isolate the interior of the container from the exterior environment. The door prevents the transfer of heat and/or humidity between the interior of the container and the exterior environment. The door is usually hinged on one side so that it can be opened and closed to provide access to the interior of the container. Unfortunately continually opening and closing the door may result in a loss of productivity and efficiency on the part of the persons using the containers. Users often desire to quickly remove items from the containers. For example, in a fast food setting, a food preparer may want to be able to quickly access food components (e.g., hot dog buns, hot dogs) to prepare the finished food product (e.g., a hot dog in the bun with desired toppings). In other situations, the container may be provided with an opening that does not include a barrier between the exterior environment and the interior of the container. This arrangement results in a loss of efficiency due to excess heating, cooling, and or humidifying. Accordingly, it would be desirable to provide an improved food container for housing items such as food. It should be understood that the claims define the scope of the subject matter for which protection is sought, regardless of whether any of the aforementioned disadvantages are overcome by the subject matter covered by the claims. Also, the terms recited in the claims should be given their ordinary and customary meaning as would be recognized by those of skill in the art, except, to the extent a term is used herein in a manner more expansive than its ordinary and customary meaning, the term should be given its ordinary and customary meaning plus the additional expansive meaning, or except if a term has been explicitly defined to have a different meaning by reciting the term followed by the phase “as used herein shall mean” or similar language. Accordingly, the claims are not tied to any particular embodiment, feature, or combination of features other than those explicitly recited in the claims. | <SOH> SUMMARY <EOH>One embodiment relates to a food container which comprises at least one opening through which food is moved and a humidity source in fluid contact with an air stream providing humidity to the air stream. The air stream is directed across the opening to form a barrier between the interior of the container and the exterior environment. Another embodiment relates to a food container which defines at least one opening through which food is moved. An air curtain system provides a humidified air curtain over the opening. Another embodiment relates to a container comprising a heating element disposed in the container, at least one opening through which food is moved between the interior and exterior of the Container, and at least one duct configured to direct an air stream across the opening to form a barrier between the interior of the container and the exterior environment. The heating element is used to at least one of cook food, rethermalize food, and maintain food at a temperature. Another embodiment relates to a container comprising at least one opening through which items are moved between the interior and the exterior of the container, a support surface in the container for supporting the items, and an air curtain system providing an air curtain over the opening. A portion of the air stream flowing over and around the items. Another embodiment relates to a container comprising at least one opening through which items are moved between the interior and the exterior of the container and a duct system configured to direct an air stream across the opening, the duct system comprising a plurality of air returns. At least one of the air returns is positioned adjacent to the opening and receives at least a portion of air stream. The portion of the air stream forming a barrier between the interior of the container and the exterior environment. The items are configured to be positioned substantially between at least another one of the air returns and the opening. The another one of the air returns being configured to receive another portion of the air stream. Another embodiment relates to a container comprising at least one opening through which items are moved out of the container, an air curtain provided over the opening to form a barrier between an interior environment of the container and an exterior environment, and a first side positioned substantially opposite the opening. The first side comprising at least one air return which is configured to receive a portion of the air from the air curtain. Another embodiment relates to a container comprising at least one opening through which items are moved between the interior and exterior of the container and an air curtain provided over the opening to form a barrier between the interior of the container and the exterior environment. The air in the air curtain is used to maintain the temperature and the humidity of the interior of the container at substantially controlled levels. Another embodiment relates to a container configured to house food comprising at least one fan configured to output an air stream and a baffle configured to receive the air stream from the fan. The air stream from the baffle passes over a water source to humidify the air stream. The humidified air stream is circulated in the container to maintain the water content of the food at or above a set level. | 20040123 | 20070522 | 20050811 | 71421.0 | 1 | PELHAM, JOSEPH MOORE | FOOD CONTAINER | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,763,785 | ACCEPTED | Catadioptric light distribution system | A Catadioptric Light Distribution System is disclosed. The system collects and collimates the hemispherical pattern of light emitted by a Lambertian light emitting diode (LED) into a collimated beam directed essentially parallel to the optical axis of the LED. The system comprises a circular condensing lens having a center axis that is aligned with the optical axis of the LED and which is configured to receive an collimate a portion of the light from the LED defined by a central cone of light centered around the optical axis. A parabolic reflector having circular opening formed therethrough is centered on the center axis of the parabolic reflector and is positioned around the LED to receive and redirect the light which does not form the cone that impinges upon the condensing lens in a collimated annular beam in a direction away from the condensing lens. The light reflected and culminated by the parabolic reflector is directed onto a circular annular double bounce mirror which is configured and positioned to receive the annular beam from the parabolic reflector and reflect that beam of light 180° so that it is collimated in an annular beam which passes around the edge of the condensing lens. Thus, substantially all the light emitted by the LED is culminated into a beam of light that is substantially parallel to the optical axis of the LED by either the condensing lens or by the combination of the parabolic reflector and the double bounce mirror. | 1. A catadioptric light distribution system comprising: a light emitting diode (LED) having an optical axis and capable of emitting light in an essentially hemispherical pattern distributed 360 degrees around said optical axis and in multiple directions from zero degrees along the optical axis to approximate 90 degrees measured from the optical axis; a circular condensing lens having a center axis aligned with said optical axis and positioned apart from said LED, said condensing lens configured to receive and collimate a central cone of the light emitted from said LED, said cone of light being essentially centered around said optical axis; a parabolic reflector having a center axis aligned with said optical axis of said LED, said parabolic reflector having a circular opening formed therethrough centered on said center axis, said opening dimensioned to allow said cone of light from said LED to pass through said parabolic reflector and impinge on said condensing lens, said parabolic reflector positioned around said LED to receive that portion of the light emitted by said LED that does not pass through said opening; said parabolic reflector configured to direct said light received from said LED in an annular beam in a direction parallel to the optical axis but in a direction away from said condensing lens; a circular annular double bounce mirror configured and positioned to received the annular beam of light from said parabolic reflector and reverse the direction of that light 180 degrees and form in an annular collimated beam essentially parallel to said optical axis around said condensing lens; Whereby substantially all of the light emitted by said LED is collimated into a beam of light substantially parallel to said optical axis of said LED. 2. A catadioptric light distribution system as claimed in claim 1 wherein said LED is a Lambertian pattern LED. 3. A catadioptric light distribution system as claimed in claim 1 wherein said condensing lens is positioned and has a diameter sufficient to receive a cone of light from said LED having a conical angle of between about 30 and about 50 degrees measured from the optical axis. 4. A catadioptric light distribution system as claimed in claim 1 where in said parabolic reflector is dimensioned and configured to receive a toroid of light from said LED having a toroidal angle of the difference between about 30 to about 90 degrees to the difference between about 50 to about 90 degrees measured from said optical axis. 5. A catadioptric light distribution system as claimed in claim 1 where in said circular annular double bounce mirror comprises a first circular annular mirror having, in cross section, a flat face angled at essentially 45 degrees as measured from said optical axis, said first circular annular mirror having a first interior circular edge and a first exterior circular edge, and a second circular annular mirror having a second circular interior edge joined to said first exterior circular edge of said first circular annular mirror, and a second circular exterior edge, said second circular annular mirror having, in cross section, a flat face that is at an angle of essentially 90 degrees with respect to said first circular annular mirror. 6. A catadioptric light distribution system as claimed in claim 5 wherein said circular condensing lens has a diameter and said first circular exterior edge and said second circular interior edge have a diameter that is substantially equal to said diameter of said condensing lens. 7. A catadioptric light distribution system for an automobile comprising: a Lambertian pattern light emitting diode (LED) having an optical axis and capable of emitting light in an essentially hemispherical pattern around said optical axis; a circular condensing lens having a focal point and a center axis aligned with said optical axis and positioned with said LED at said focal point of said condensing lens, said condensing lens configured to receive and collimate a central cone of the light emitted from said LED, said cone of light being essentially centered around said optical axis a parabolic reflector having a focal point and a center axis aligned with said optical axis of said LED, said parabolic reflector having a circular opening formed therethrough centered on said optical axis, said opening dimensioned to allow said cone of light from said LED to pass through said parabolic reflector and impinge on said condensing lens, said parabolic reflector configured and positioned around said LED to receive that portion of the light emitted by said LED that does not pass through said opening; said parabolic reflector configured to direct said light received from said LED in an annular beam in a direction parallel to the optical axis but in a direction away form said condensing lens; a circular annular double bounce mirror configured and positioned to received the annular beam of light from said parabolic reflector and reverse the direction of that beam of light 180 degrees and form in an annular collimated beam around said condensing lens essentially parallel to said optical axis; Whereby substantially all of the light emitted by said LED is collimated into a beam of light substantially parallel to said optical axis of said LED. 8. A catadioptric light distribution system as claimed in claim 7 wherein said condensing lens is positioned and has a diameter sufficient to receive a cone of light from said LED having a conical angle of between about 30 and 50 degrees as measured from the optical axis. 9. A catadioptric light distribution system as claimed in claim 7 where in said parabolic reflector is dimensioned and configured to receive a toroid of light from said LED having a toroidal angle of the difference between about 30 to about 90 degrees to the difference between about 50 to about 90 degrees as measured from said optical axis. 10. A catadioptric light distribution system as claimed in claim 7 where in said circular annular double bounce mirror comprises a first circular annular mirror having, in cross section, a flat face angled at essentially 45 degrees as measured from said optical axis, said first circular annular mirror having a first interior circular edge and a first exterior circular edge, and a second circular annular mirror having a second circular interior edge joined to said first exterior circular edge of said first circular annular mirror, and a second circular exterior edge, said second circular annular mirror having, in cross section, a flat face that is at an angle of essentially 90 degrees with respect to said first circular annular mirror. 11. A catadioptric light distribution system as claimed in claim 10 wherein said circular condensing lens has a diameter and said first circular exterior edge and said second circular interior edge have a diameter that is substantially equal to said diameter of said condensing lens. 12. A catadioptric light distribution system as claimed in claim 11 wherein said parabolic reflector has an exterior diameter that is substantially the same as the diameter of said condensing lens. | BACKGROUND OF INVENTION 1. Field of the Invention The present invention relates to a catadioptric light distribution system for collimating a hemispherical pattern of light distributed by a lambertian light emitting diode into a collimated beam of light directed essentially along the optical axis of the LED. More particularly, the present system relates to a catadioptric light distribution system that can be used to culminate a beam light from an LED for automotive lighting purposes. 2. Detailed Description of the Prior Art Light emitting diodes, commonly called LEDs, are well known in the art. LEDs are light producing devices that illuminate solely as a result of electrons moving in a semi-conductor material. Consequently, LEDs are advantageous as compared to filament type bulbs because an LED has no filament to burn out. Consequently, LEDs generally have a life as long as a standard transistor, and as a result have been utilized in a variety of different devices where longevity of the light source is important. Originally, LEDs were quite small and limited in their capacity to produce light. However, advances in the technology have increased the amount of light (luminous flux (Lm) or radiometric power (mW)) that an LED is capable of producing. Consequently, practical applications for LEDs have been expanded to include automotive lighting purposes. Lambertian LEDs are also well known in the art. LEDs typically have a hemispherical top that is centered on an optical axis through the center of the LED, however other top surfaces can be used. The light emitted by the Lambertian LED is in a hemispherical pattern from 0° to approximately 90° measured from the optical axis and 360° around the optical axis. In addition, LEDs are typically mounted on a heat sink that absorbs the heat generated by the LED when it is producing light. Unfortunately, conventional optical systems cannot culminate all of the light emitted by a Lambertian LED because of the wide spread of light emitted by and physical constraints of a Lambertian LED. For example, U.S. Pat. No. 6,558,032-Kondo et al. illustrates one prior art attempt to effectively distribute light from a Lambertian LED. However, the various light distribution systems illustrated in Kondo et al. are not very effective in collimating the light from an LED into an effective beam. Accordingly, it is a primary object to the present invention to provide a catadioptric light distribution system that effectively collimates substantially all the light emitted by a Lambertian LED into a beam of light essentially parallel to the optical axis of the LED. SUMMARY OF THE INVENTION A catadioptric light distribution system in accordance with the present invention comprises an LED having a central optical axis and which is capable of emitting light in a hemispherical pattern distributed 360° around the optical axis and from 0° to approximately 90° measured from the optical axis. A circular condensing lens having a center axis is aligned so that the center axis of the circular condensing lens coincides with the optical axis of the LED. The condensing lens is positioned apart from the LED and the condensing lens is configured to receive and collimate a central cone of light emitted from the LED that is centered around the optical axis. A parabolic reflector is also provided. The parabolic reflector has a center axis through the center of the parabolic reflector which is aligned with the optical axis of the LED. The parabolic reflector also has a circular opening through the parabolic reflector that is centered on the optical axis. The circular opening is dimensioned to allow the cone of light from the LED to pass through the parabolic reflector and impinge upon the condensing lens. The parabolic reflector is positioned around the LED in a position to receive that remaining portion of the light emitted by the LED that does not pass through the opening. The parabolic reflector is configured to redirect the light received from the LED into an annular beam that is focused in a direction parallel to the optical axis but in a direction away from the condensing lens. A circular annular double bounce mirror is positioned and configured to receive the annular beam of light from the parabolic reflector and reverse the direction of that light a 180° so that it forms an annular culminated beam around the outside edge of the condensing lens. The light culminated by the condensing lens and the light culminated by the circular annular double bounce mirror form a single culminated beam parallel to the optical axis. Thus, the present invention collects substantially all of the light emitted by a Lambertian LED and focuses that light into a culminated beam in a direction along the optical axis of the Lambertian LED. DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a prior art system using a Lambertian LED and a parabolic reflector. FIG. 2 illustrates a prior art system using a Lambertian LED and a condensing lens. FIG. 3 is a top view of a preferred embodiment of the present invention. FIG. 4 is a cross sectional side view of the present invention taken along lines 5-5 in FIG. 4 showing the light distribution produced by the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 discloses a prior art system which uses a Lambertian LED 10 and a parabolic reflector 12. Because of the heat generated by a LED, the LED includes a heat sink 14 on the back of the LED. The parabolic reflector 12 is configured to culminate light generated at the focal point of the paraboloid and culminate that light outwardly. The LED is placed at the focal point of the parabolic reflector and it is facing the parabolic reflector 12 and aligned so that the optical axis of the LED and the center axis of the parabola 16 are aligned. Because the Lambertian LED emits light 360° around the optical axis and from 0 to about 90° as measured from the optical axis, a hemispherical light distribution pattern is produced. Unfortunately, because of the heat sink 14 mounted on the base of the Lambertian LED 10, light reflected by the center of the parabolic reflector 12 is essentially blocked by the heat sink 14 so that a dark shadow column as depicted by the dotted lines 18, is produced in the center of reflector system. Thus, a significant portion of the light emitted by the Lambertian LED 10 is blocked by the heat sink 14 in this prior art system. FIG. 2 represents another prior art system for culminating the light produced by a Lambertian LED 10. A circular condensing lens 20 is positioned apart from the LED 10 with the center axis of the condensing lens 20 aligned with the optical axis 16 of the Lambertian LED. Thus, the condensing lens 20 receives a cone of light from the LED 10 with the conical angle of the cone of light being a function of the diameter of the condensing lens 20. Because a condensing lens is capable of effectively culminating light impinging upon its surface an angle no greater than approximately 50°, that portion of the hemisphere of light produced by the LED as shown by arrows 22 in FIG. 2 cannot be effectively collimated. This reduces the amount of light from the LED that can be focused into a collimated beam using this prior art system. With reference to FIGS. 3 and 4 a preferred embodiment of the present invention is illustrated. An LED 10 is shown mounted on a heat sink 14. The LED 10 has an optical axis 16 which extends upwardly as shown in FIG. 3. A circular condensing lens 30 is positioned apart from the LED with the center axis of the circular condensing lens aligned with the optical axis 16 of the LED and the LED at the focal point of the condensing lens 30. The condensing lens 30 typically has a first flat face 32 and a second curved face 34. A parabolic reflector 36 is positioned so that its center axis aligns with the optical axis 16 of the LED 10 and its focal point aligns with the LED. The parabolic reflector 36 has a circular opening 38 formed there through which opening is centered on the center axis of the parabolic reflector 36. Positioned behind the LED 10 and also centered on the optical axis of the LED is a circular annular double bounce mirror 40. With reference to FIG. 5, it can be seen that the circular annular double bounce mirror 40 comprises a first circular annular mirror 42 which in cross section has a flat reflecting surface 44 which is angled at an angle “a” that is 45° as measured from the optical axis 16. The circular annular double bounce mirror 40 also comprises a second circular annular mirror 46 which in cross section has a flat mirror surface 48 that is aligned at an angle of 90° with respect to the flat mirror surface 44. The circular annular mirror 42 has a first interior circular surface 50 which defines a circular opening 52 aligned around the optical axis 16. The circular annular mirror 42 also has a second exterior circular surface 58 that extends entirely around the perimeter of the circular annular double bounce mirror 40. Mirror 42 has two reflecting surfaces 44 and 48 oriented 90° with respect to one another and which are joined along an edge 56. With reference to FIG. 4, parabolic reflector 36 has an interior edge 60 which defines the condensing lens aperture 38 centered on the optical axis 16 and an exterior edge 62 which defines the circular open face of the parabolic reflector 36. Parabolic reflector 36 has an interior curved reflecting surface 64 which is formed to receive a toroid of light from the LED 10 and reflect that light in a culminated annular beam towards the flat mirror surface 44 of first circular annular mirror 42. The aperture 38 in parabolic reflector 36 allows a cone of light having a conical angle of “b” to pass through the aperture 38 and impinge upon the flat surface 32 of condensing lens 30. The combination of the flat surface 32 and the curve surface 34 of lens 30 are configured to culminate the cone of light passing through aperture 38 into a beam of light parallel to the optical axis 16 as shown by the arrows 70 in FIG. 5. The conical angle “b” may typically be between 30 and 50 degrees as measured from the optical axis. Angle “b” is a function of the diameter of condensing lens 20 and the diameter of opening 38 in parabolic reflector 36. These diameters can be varied to allow as broad a cone of light that can be effectively collimated by lens 20 to be passed through aperture 38. Similarly, a toroid of light from LED 10 strikes the curve surface 64 of parabolic reflector 36. That toroid of light can have a toroidial angle “c” the difference of between about 30° to about 90° (i.e. 60°) as measured from the optical axis to between the difference about 50° to 90° (i.e. 40°) as measured from the optical axis depending on the conical angle “b” of the cone of light passing through opening 38. That toroid of light is reflected downwardly in a collimated annular beam of light onto flat mirror surface 44 which, in turn, directs the light 90 degrees across to the flat surface 48 of second annular circular mirror 46 which, in turns, reflects the light 90 degrees in a direction parallel to the optical axis 16 as illustrated by the arrows 72 in FIG. 5. Thus, the circular annular double bounce mirror redirects the light by 180°. Because the circular edge of condensing lens 30 essentially coincides with the circular junction 56 of surfaces 44 and 48 of annular mirror 42 because the diameters are substantially the same, the light reflected by the circular annular double bounce mirror forms an annular beam which passes by the edge of circular condensing lens 30 and blends with the light collimated by condensing lens 20. As can be seen by FIG. 5, substantially all of the hemispherical pattern of light distributed by the Lambertian LED 10 is effectively culminated into a beam of light parallel to the optical axis 16 as is depicted by the arrows 70 and 72. While elements of the preferred embodiment illustrated in FIGS. 3-4 are shown floating without visible support, it should be understood by one of ordinary skill in the art that appropriate structural supports such as lens holder 70 may be supplied to support the various elements of the system. It should also be expressly understood that various modifications, alterations or changes may be made to the preferred embodiment illustrated above without departing from the spirit and scope of the present invention as defined in the appended claims. | <SOH> BACKGROUND OF INVENTION <EOH>1. Field of the Invention The present invention relates to a catadioptric light distribution system for collimating a hemispherical pattern of light distributed by a lambertian light emitting diode into a collimated beam of light directed essentially along the optical axis of the LED. More particularly, the present system relates to a catadioptric light distribution system that can be used to culminate a beam light from an LED for automotive lighting purposes. 2. Detailed Description of the Prior Art Light emitting diodes, commonly called LEDs, are well known in the art. LEDs are light producing devices that illuminate solely as a result of electrons moving in a semi-conductor material. Consequently, LEDs are advantageous as compared to filament type bulbs because an LED has no filament to burn out. Consequently, LEDs generally have a life as long as a standard transistor, and as a result have been utilized in a variety of different devices where longevity of the light source is important. Originally, LEDs were quite small and limited in their capacity to produce light. However, advances in the technology have increased the amount of light (luminous flux (Lm) or radiometric power (mW)) that an LED is capable of producing. Consequently, practical applications for LEDs have been expanded to include automotive lighting purposes. Lambertian LEDs are also well known in the art. LEDs typically have a hemispherical top that is centered on an optical axis through the center of the LED, however other top surfaces can be used. The light emitted by the Lambertian LED is in a hemispherical pattern from 0° to approximately 90° measured from the optical axis and 360° around the optical axis. In addition, LEDs are typically mounted on a heat sink that absorbs the heat generated by the LED when it is producing light. Unfortunately, conventional optical systems cannot culminate all of the light emitted by a Lambertian LED because of the wide spread of light emitted by and physical constraints of a Lambertian LED. For example, U.S. Pat. No. 6,558,032-Kondo et al. illustrates one prior art attempt to effectively distribute light from a Lambertian LED. However, the various light distribution systems illustrated in Kondo et al. are not very effective in collimating the light from an LED into an effective beam. Accordingly, it is a primary object to the present invention to provide a catadioptric light distribution system that effectively collimates substantially all the light emitted by a Lambertian LED into a beam of light essentially parallel to the optical axis of the LED. | <SOH> SUMMARY OF THE INVENTION <EOH>A catadioptric light distribution system in accordance with the present invention comprises an LED having a central optical axis and which is capable of emitting light in a hemispherical pattern distributed 360° around the optical axis and from 0° to approximately 90° measured from the optical axis. A circular condensing lens having a center axis is aligned so that the center axis of the circular condensing lens coincides with the optical axis of the LED. The condensing lens is positioned apart from the LED and the condensing lens is configured to receive and collimate a central cone of light emitted from the LED that is centered around the optical axis. A parabolic reflector is also provided. The parabolic reflector has a center axis through the center of the parabolic reflector which is aligned with the optical axis of the LED. The parabolic reflector also has a circular opening through the parabolic reflector that is centered on the optical axis. The circular opening is dimensioned to allow the cone of light from the LED to pass through the parabolic reflector and impinge upon the condensing lens. The parabolic reflector is positioned around the LED in a position to receive that remaining portion of the light emitted by the LED that does not pass through the opening. The parabolic reflector is configured to redirect the light received from the LED into an annular beam that is focused in a direction parallel to the optical axis but in a direction away from the condensing lens. A circular annular double bounce mirror is positioned and configured to receive the annular beam of light from the parabolic reflector and reverse the direction of that light a 180° so that it forms an annular culminated beam around the outside edge of the condensing lens. The light culminated by the condensing lens and the light culminated by the circular annular double bounce mirror form a single culminated beam parallel to the optical axis. Thus, the present invention collects substantially all of the light emitted by a Lambertian LED and focuses that light into a culminated beam in a direction along the optical axis of the Lambertian LED. | 20040123 | 20060418 | 20050728 | 95684.0 | 0 | MAY, ROBERT J | CATADIOPTRIC LIGHT DISTRIBUTION SYSTEM | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,763,803 | ACCEPTED | Rotable inventory calculation method | A method for conducting a repairable inventory analysis calculates the minimum number of repairable parts to be held in inventory while still being able to satisfy the demand for spare parts even in view of uncertain repair lead times. The method uses a set of equations that relates a customer service level to arbitrary probability distribution functions of a repair lead-time and a part arrival process. The distributions are then searched to locate the optimal inventory level in the distribution. | 1. A method of optimizing rotable inventory, comprising: selecting a desired customer service level; obtaining at least one characteristic of a part repair lead-time distribution; computing a proposed inventory level based on said at least one characteristic; determining a calculated customer service level corresponding to the proposed inventory level; comparing the calculated customer service level with the desired customer service level; and selecting the proposed inventory level as an optimized inventory level if the calculated customer service level is within a selected convergence threshold with respect to the desired customer service level. 2. The method of claim 1, wherein said at least one characteristic is a mean [ and a variance a of the part repair lead-time distribution. 3. The method of claim 2, wherein the step of computing a proposed inventory level comprises: refinancing a probability term β having a distribution reflected by a difference term As; and calculating the proposed inventory as I=A·(R−W)−μ+Δβ·σ wherein I is the proposed inventory value, A is a part arrival value, R is a maximum repair time and W is a desired turnaround time window. 4. The method of claim 3, wherein the probability term β is bound by a left bound value BL and a right bound value BR, and wherein the method further comprises: shifting the probability term β to the left bound value BL and defining a new probability term P between the left bound value BL and the right bound value BR if the calculated customer service level is less than the desired customer service level; and shifting the probability term β to the right bound value BR and defining a new probability term β between the left bound value BL and the right bound value BR if the calculated customer service level is greater than the desired customer service level and if the difference between the calculated customer service level and the desired customer service level is greater than the convergence threshold value. 5. The method of claim 4, further comprising repeating the computing, determining, comparing and shifting steps until the selecting step is executed. 6. The method of claim 1, further comprising repeating the computing, determining, and comparing steps until the selecting step is executed. 7. The method of claim 1, wherein the desired customer service level is a desired on-time delivery, and the calculated customer service level is a mean on-time delivery, wherein the desired on-time delivery and the mean on-time delivery are represented by a mean of a number of on-time delivered parts per time unit divided by a mean of arrivals per time unit. 8. The method of claim 7, wherein a number of arrivals per time unit is a constant number, and wherein the mean of arrivals per time unit is set equal to the constant number. 9. The method of claim 1, wherein a number of arrivals per time unit is randomly variable. 10. The method of claim 9, wherein the method further comprises: obtaining an arrival value having a distribution G and an inventory value having a distribution Φ; obtaining a distribution of the calculated customer service level based from the distributions G and Φ; and conducting the step of the determining the calculated customer service level based on the distribution of the calculated customer service level. 11. The method of claim 9, wherein the method further comprises approximating the randomly variable number of arrivals per time unit with a constant number of arrivals per time unit. 12. The method of claim 1, wherein the method optimizes rotable inventory for an asset having a plurality of individual parts, wherein the step of selecting the desired customer service level comprises selecting the desired customer service level for the individual parts, and wherein the method further comprises: conducting the obtaining, computing, determining, comparing, and selecting steps to obtain the optimized inventory level for each of said plurality of parts; summing the optimized inventory level for each of said plurality of parts to obtain a total optimized inventory level; calculating a total rotable inventory cost from the total optimized inventory level; and minimizing the total rotable inventory cost. 13. The method of claim 12, wherein the minimizing step is conducted via a constrained optimization process. 14. A computer system for optimizing rotable inventory, comprising: a user interface; a processor that executes an algorithm to determine an optimized inventory level, the algorithm comprising the steps of selecting a desired customer service level, obtaining at least one characteristic of a part repair lead-time distribution, computing a proposed inventory level based on said at least one characteristic, determining a calculated customer service level corresponding to the proposed inventory level, comparing the calculated customer service level with the desired customer service level, and selecting the proposed inventory level as an optimized inventory level if the calculated customer service level is within a selected convergence threshold with respect to the desired customer service level; and a memory that stores data to be used by the processor to execute the algorithm. 15. A method of maintaining an optimized rotable inventory level, comprising: determining an optimized inventory level, the determining step including: selecting a desired customer service level; obtaining at least one characteristic of a part repair lead-time distribution; computing a proposed inventory level based on said at least one characteristic; determining a calculated customer service level corresponding to the proposed inventory level; comparing the calculated customer service level with the desired customer service level; selecting the proposed inventory level as an optimized inventory level if the calculated customer service level is within a selected convergence threshold with respect to the desired customer service level; and maintaining an inventory level responsive to said optimized inventory level. | TECHNICAL FIELD The present invention relates to a method for conducting repairable inventory analysis, and more particularly to a method for computing repairable inventory requirements under uncertainties. BACKGROUND OF THE INVENTION Many industries use repairable, or “rotable,” inventories for economic reasons. Rotable parts are different from “expendable” parts, which are parts having a low enough value that the repair of such parts does not make economic sense. Rather, such expendible parts are merely discarded and replaced with new parts. Rotable parts, by contrast, tend to be more expensive, making their repair and reinstallation, rather than simple replacement with a new part, more economically justifiable. Repairing a part or getting a new replacement can have uncertain lead times (i.e., the time interval between ordering a replacement and its delivery), and therefore rotable part inventories are used to bridge the gap between demand for the part and its supply as well as to maintain a selected high level of customer service. Due to the high cost of rotable parts, however, it is desirable to minimize the number of rotable parts held in inventory. But balancing minimal inventory with a desired customer service level (i.e., a measure of customer service defined as a ratio of parts delivered on time to the number of parts ordered) is difficult because the lead times for repairing parts and obtaining replacements are uncertain. Thus, there is a desire to calculate a minimum rotable inventory level that can satisfy a given customer service level. Currently-known attempts to create models solving this problem have not provided satisfactory solutions because they use deterministic methods that assume parts arrive into a repair shop and are repaired according to standard time distributions. In actual practice, however, arrivals and repair time are much more uncertain. Thus, current models for optimizing rotable inventory do not generate satisfactory solutions because they fail to take these uncertainties into account. Further, assets may contain multiple types of rotable parts and the asset service level is determined by the service levels of individual part types. The interrelationships between those part types make it more difficult to determine optimal inventory levels for individual part types to achieve a desired assert service level. Deterministic methods are unable to consider the interrelationships between the parts. There is a desire for a method that can calculate the optimum amount of rotable inventory needed to satisfy a given customer service level while taking these uncertainties into account. SUMMARY OF THE INVENTION The present invention is directed to a method for conducting a repairable inventory analysis that calculates the minimum number of repairable parts to be held in inventory while still being able to satisfy the demand for spare parts even in view of uncertain repair lead times. Given a service level, which is defined as a total number of on-time delivered parts delivered by the total number of requested parts, one embodiment of the method uses a set of equations that relates the optimal rotable inventory level to a customer service level, given arbitrary probability distributions of a repair lead-time and a part arrival process. A search procedure is used to find the optimal rotable inventory level. In one embodiment, it is assumed that the number of parts requiring repair in a given time unit is constant and a part repair lead-time distribution is given. The mean and variance of the number of available parts at any time (or the amount of back orders, if the mean is negative) are computed. In this embodiment, this number is random and cab be proven to be normally distributed. A probability term that corresponds to a given probability level under a normal distribution is computed or looked up from a standard normal distribution table. The corresponding inventory level is computed from the probability term, the mean, and the variance. The number of on-time deliveries is then calculated based on its distribution, which is obtained by truncating the above-mentioned normal distribution with [0,A] and lumping the probability in each tail to the corresponding boundary. If the on-time delivery value is acceptably close to a desired on-time delivery value, the inventory level is deemed to be optimal and can meet desired customer service levels without having excessive, costly extra parts on hand. Otherwise, the probability level is updated following a search procedure, and the above calculation is repeated until the optimal inventory level is obtained. In another embodiment, it is assumed that the number of arriving parts in a given time unit is random. The algorithm described in the previous embodiment still applies, except that the distribution of on-time delivery is more complicated and difficult to obtain in a closed form. Equations for computing the above distribution numerically, and for computing the mean and variance of the number of available parts at any time, are provided. In another embodiment, an asset with multiple part types is analyzed. The asset service level is computed as the product of service levels of individual part types. With the above algorithm, inventory levels for individual part types can be obtained with given service levels, and the problem is formulated as finding the optimal service levels for individual part types. With known per-unit inventory costs, the optimization problem is formulated as minimizing total inventory cost, subject to the above service level relations, and the inventory-service level relationships for individual part types. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram illustrating a rotable inventory problem to be addressed by the invention; FIG. 2 is a graph depicting examples of on-time delivery distributions; FIG. 3 is a flow diagram illustrating an example of a method used to find an optimal inventory level according to one embodiment of the invention; and FIG. 4 is a block diagram illustrating one embodiment of a computer system that can implement the inventive method. DETAILED DESCRIPTION OF THE EMBODIMENTS The invention determines a minimum rotable inventory level that can still satisfy a given desired level of customer service by generating a set of equations that links customer service level to arbitrary probability distribution functions (including empirical distributions) reflecting repair lead-time and part arrival at a repair shop. The method represents a customer service level as a mean of the number of on-time delivered parts during a unit time interval divided by a mean number of arrivals per time unit to obtain a distribution of on-time delivered parts per time unit. A search procedure is used to locate the optimal inventory level using the distribution. Assets having multiple rotable part types can be analyzed using a constrained optimization method. FIG. 1 is a block diagram illustrating the rotable inventory problem to be addressed and optimized. As shown in the figure, rotable part arrivals 100 reach a repair shop according to an arrival probability distribution, which reflect the pattern in which parts arrive at a repair shop at a given time, and go through the repair process having a repair lead-time 102 with its own probability distribution. The arrival distribution and the repair lead-time distribution may be different from each other and, due to the nature of real world constraints, is uncertain. The customer service level is determined based on a desired turn around time (TAT) 104. The customer service level is defined as the probability that a given part repair turnaround time is less than or equal to the customer's desired/contracted turnaround time 104. In FIG. 1, the path containing the desired turnaround time 104 corresponds to customer requests for obtaining repaired parts or replacements back. The desired turnaround time distribution 104 and the repair lead-time distribution 102 are then considered together to determine the optimum rotable inventory level 106 from which deliveries of repaired and replacement parts will be drawn. The algorithms through which the optimal rotable inventory is calculated will now be described. For purposes of explanation in the equations below, I represents the rotable inventory level 106, W the desired turnaround time 104, and α represents a desired on-time delivery rate. The inventive method aims to find a minimum rotable inventory level I* at which the probability that customer turnaround time is less than or equal to the desired turnaround time value W is greater than or equal to the given desired probability level α. In other words, the method aims to find a minimum rotable inventory level I* at which there is a high probability (as defined by α) that the inventory level will be high enough to meet or exceed customer service expectations with respect to the turnaround time. As noted above, the repair lead-time is uncertain, which therefore makes the customer's turnaround time uncertain as well. In other words, there is no way to predict how quickly a customer can get a repair done or a replacement part installed With the desired turnaround time 104, customer service level is defined as the probability that the customer turnaround time for getting a repair or replacement is less than or equal to the desired/contracted turnaround time 104, that is, the probability that a customer part demand is satisfied in a timely fashion. In the equation below, ωTAT represents the random customer turnaround time (i.e., the time needed for a given part repair or replacement). Let α represent the desired service level. Then the customer service level requirement can be expressed by the following equation: Pr(ωTAT≦W)≧α (1) According to the mathematical Law of Large Numbers, which is known in the art, the probability described in Equation 1 can be rewritten as: Pr ( w TAT ≤ W ) = lim k → ∞ ( m k n k ) ( 2 ) where mk is the total number of on-time-delivered parts by time k (e.g., a day) and nk the total number of parts that need to be repaired (i.e., total repair demand) by time k. Equation 2 holds true because the ratio of on-time delivered parts to the total number of repaired parts will reflect the degree to which customer-requested turnaround times have been met. If the number of parts arriving at the repair shop during a given time unit k is constant, the total number of parts that need to be repaired nk during the time unit can be expressed as: nk=A·(k−W) (3) where A is the number of parts that arrive by time k. As can be seen in Equation 3, the total repair demand nk therefore is the number of parts A that arrive by time k multiplied by a difference between the time k and the desired turnaround time W. For the discussion below, assume that a random repair lead-time τ is within a minimum repair time r and a maximum repair time R (i.e., in the interval [r, R]). Based on this information, it is known with certainty that parts that are starting to be repaired at and before time (k−R) will be completed at time k, and parts starting after time (k−r) will still be in repair at time k. Parts having repair start times that start within time [k−R, k−r], however, may or may not be done by time k; in other words, there is a probability, rather than a certainty, that these parts will be done by time k. The total number of repaired parts that will be completely repaired by time k can therefore be expressed as: R k = A · ( k - R ) + ∑ i = k - R + 1 k - r ∑ j = 1 A X ij ( k ) ( 4 ) where Xij(k) is a random binary variable equal to either 0 or 1. Xij(k) represents a repair status at time k for a given jth part that arrived at time i, where j=1, 2, . . . A; and i=k−R+1, k−R+2, . . . n−r. Xij(k) will equal 1 if the part is done being repaired at time k and will equal 0 otherwise. Because A is a constant in this example, reflecting a constant number of part arrivals per time unit k, the number of on-time deliveries at a time k (i.e., OTk) will fall in the interval [0, A]. OT k = Min ( A , Max ( 0 , I + R k - n k - 1 ) ) = Min ( A , Max ( 0 , I - A · ( R - W ) + A + ∑ i = k - R + 1 k - r ∑ j = 1 A X ij ( k ) ) ) ( 5 ) In other words, the number of on-time deliveries will be the smaller of: (1) the total number of parts that have arrived A or (2) the larger of 0 and the difference between the total rotable inventory level and the number of parts whose repairs have been completed by time k. The total number of on-time deliveries by time k can therefore be expressed as: m k = ∑ i = 1 k OT i ( 6 ) By replacing mk and nk in Equation (2) with the expressions in Equations (3) and (6), the probability of on-time delivery of repaired parts can be expressed as: Pr ( w TAT ≤ W ) = lim k → ∞ ( m k n k ) = 1 A · lim k → ∞ ( ∑ i = 1 k OT i k - W ) = μ OT A ( 7 ) where μOT represents the mean on-time delivery of replacement/repaired parts. With the expression in Equation 7, it is now possible to find the minimum inventory level 1* (which determines the mean on-time delivery μOT) such that μ OT A ≥ α (i.e., the mean number of on-time delivered parts divided by the number of requested parts per time unit, which represents the actual delivery rate, is greater than or equal to the desired on-time delivery rate α). Expressed another way, it is now possible to find the minimum inventory level I* such that μOT≧═A. For this calculation, assume that Xij(k) for all (i, j) are independent; that is, the repair of one part is not affected by the repair of another part. According to the Central Limit Theorem, which is known in the art, the term z k = ∑ i = k - R + 1 k - r ∑ j = 1 A X ij ( k ) used in calculating the number of on-time deliveries at time k (OTk) in Equation 5 above has a normal distribution with the following mean μ and variance σ. μ = μ k = ∑ i = k - R + 1 k - r ∑ j = 1 A E ( X ij ( k ) ) = A · ∑ i = k - R + 1 k - r E ( X i ( k ) ) = A · ∑ i = r R - 1 G i ( 8 ) σ 2 = σ k 2 = ∑ i = k - R + 1 k - r ∑ j = 1 A Var ( X ij ( k ) ) = A · ∑ i = r R - 1 G i · ( 1 - G i ) ( 9 ) where Gi represents the repair lead-time distribution (i.e., the probability that repair lead-time will be less than or equal to time i). Referring to FIG. 2, it can be seen that the term (I+Rk−nk−1), which reflects a given inventory level (I) plus the total number of parts repaired by time k (i.e., Rk) minus the total demand at time k−1 (i.e., nk−1), has a normal distribution Φ, as represented by Series 2 in FIG. 2, with a mean of μΦ=I−A·(R−W−I)+μ and a variance σ2. As also shown in FIG. 2, the on-time delivery OTk has a distribution Ψ, as represented by Series 1 in FIG. 2, that is truncated from the normal distribution Φ by removing the tails that lie beyond the area bounded by [0, A] and adding the mass probability in each tail to the mass probability at the corresponding boundary for each tail. From this information, it is simple to compute the mean on-time delivery μOT, and therefore the service level Pr (ωTAT≦W), that is possible for a given inventory level I. Given an inventory level I, the mean and variance of the normal distribution Φ can be computed using Equations (8) and (9). The probability mass distribution Ψ of OTk can also be easily computed by adding the probability in the tail portion of its distribution to the probability at the boundary corresponding to the tail. With this distributions Ψ, the mean on-time delivery μOT can be computed. Computing the required inventory I* from a specified probability for satisfying a part demand within a given turnaround time (i.e., Pr(ωTAT≦W)), however, is less straightforward than computing the mean on-time delivery μOT because the non-linear minimum/maximum function used to define on-time delivery, as shown in Equation 5, has an irregular distribution. Because of this, a search procedure, such as the one shown in FIG. 3, may be used to determine a required minimum inventory level I* that can fulfill a given desired turnaround time with a selected probability. The method shown in FIG. 3 assumes that the part repair lead-time distribution Gi is given. From this information, the method first computes the mean μ and variance σ of the part repair lead-time distribution using Equations (8) and (9) (block 150). Next, the method defines a probability term β=Pr(ζ≧A) where ζ has a normal distribution Φ as represented in Series 2 in FIG. 2 (block 152). In other words, β reflects the probability that ζ is greater than or equal to the number of parts arriving per unit time. Because β is expressed as a probability, it is clear that βε(0, 1). Further, as reflected in the expression μΦ=I−A·(R−W−I)+μ noted above, μΦ is a function of the inventory level I. The method initializes β as α (i.e., the desired on-time delivery rate) and sets its initial left and right bounds as BL and BR, respectively (block 154). The values for BL and BR can cover any desired range, and in one embodiment β lies midway between BL and BR. Next, a difference term Δβ is searched or computed from a standard normal distribution table reflecting the distribution of β via any known means (block 156); this difference term can be obtained by, for example, a standard normal distribution table. The inventory value I corresponding to the distribution of β can be calculated from I=A·(R−W)−μ+Δβ·σ, and this corresponding inventory value I is treated as a proposed inventory value for computing the on-time delivery probabilities that are eventually used to generate a mean on-time delivery value to be compared with the desired mean on-time delivery value. From the known probability mass distribution Ψ of OTk and the proposed inventory level I corresponding to β, the method computes on-time delivery probabilities for OT=0, 1, 2 . . . . A and determines the mean on-time delivery μOT based on the resulting on-time delivery probability distribution for each value of OT (block 158). The mean on-time delivery value μOT is then compared with a desired mean on-time delivery value (i.e., the method checks if μOT≦α·A) (block 160). If the mean on-time delivery value is less than the desired mean on-time delivery value, it indicates that the value selected for β and its corresponding distribution are too far to the left on a distribution graph, causing the corresponding inventory level I to be too low with respect to the desired turnaround time (e.g., the proposed inventory level I is insufficient). In response, the left bound BL is set equal to the proposed value βand β = 1 2 · ( BL + BB ) (block 162). In other words, β and BL are reset to cut the distance between the left and right bounds in half and move the position of β to a new location midway between the two bounds. The process then returns to block 156 to recompute the probability distribution of β with the new value for β as well as the new left and right bound values BL and BR. If, however, the mean on-time delivery value is greater than or equal to the desired mean on-time delivery value, the difference between the mean on-time delivery value and the desired mean on-time delivery value is then compared with a selected convergence threshold ε(i.e., μOT−α·A<ε) (block 164). The value selected for e can be any desired small value reflecting convergence between the mean on-time delivery value and the desired mean on-time delivery value. If the difference between the mean and desired mean on-time delivery values is less than the convergence value, it indicates that the proposed inventory I calculated from the value for β and its corresponding value for Δβ will result in a mean on-time delivery value that is nearly equal to the desired mean on-time delivery value within an acceptable degree. At this point, the calculated proposed inventory level reflects the minimum inventory level I* needed to fulfill the desired on-time delivery, and as noted above can be computed as I=A·(R−W)−μ+Δβ·σ (block 166). If the difference between the mean and desired mean on-time delivery values is greater than the convergence value ε, it indicates that the current value selected for β and its corresponding distribution are too far to the right on a distribution graph, causing the corresponding proposed inventory level I to be higher than needed to meet the desired turnaround time. In response, the method lets BR=β, β = 1 2 · ( BL + BB ) (block 168) before returning to block 156 to recompute the probability distribution of β with the new value for β as well as the new left and right bound values BL and BR. The process continues to iterate until the value for β results in an inventory level that causes the mean on-time delivery value to be close to the desired mean on-time delivery value within a desired convergence ε(μOT−α·A<ε). As noted above, the process shown in FIG. 3 assumes that parts arrive at a repair shop in a constant manner, where the number of arrived parts A remains the same for each time unit (e.g., per day). The theory and calculations in a case assuming that part arrivals are random are somewhat different. Generally, the inventive process handles random part arrivals by finding a way to approximate the random arrivals with a constant arrival expression, thereby allowing the process shown in FIG. 3 to be carried out for random part arrivals. More particularly, if it is assumed that the number of parts arriving at a repair shop at time k is random and represented by a random variable Ak, the total part demand by time k can be expressed as: n k = ∑ t = 0 k - W A t ( 10 ) The total number of repaired parts by time k, denoted as Rk, is also a random variable and includes repaired parts that are completed with certainty as well as parts that have a probability of being complete at time k. As explained above, given that R is a maximum repair lead-time and r is a minimum repair lead-time, it is known with certainty parts that arrive at and before time (k−R) are completed by time k, and parts starting after (k−r) are still in repair by time k. Parts that arrive within [k−R, k−r] may or may not be done by time k, causing them to be completed by time k with probability rather than with certainty. The total number of completed parts by time k can therefore be written as R k = ∑ t = 0 k - R A t + ∑ t = r R - 1 A k - t G t ) ( 11 ) Similar to the example shown in Equation 5, the number of on-time deliveries at k can therefore be expressed as OT k = Max ( 0 , Min ( A k - W , I + R k - n k - 1 ) ) = Max ( 0 , Min ( A k - W , I - ∑ t = k - R + 1 k - W - 1 A t + ∑ t = r R - 1 A k - t G t ) ) = Max ( 0 , Min ( A k - W , I + ∑ t = k - R + 1 k - W - 1 A t ( G k - t - 1 ) + ∑ t = k - W k - r A t G k - t ) ) ( 12 ) The problem is now to find the mean on-time delivery value μOT that will be greater than or equal to a desired mean on-time delivery value (i.e., μOT≦α·A), which will cause the inventory level calculated from the mean on-time delivery rate μOT to be the minimum inventory level I*. Assuming that Ak for all k are independent and with reference to the examples in Equations 8 and 9, the term zk used in calculating the number of on-time deliveries at time k can be expressed according to the Central Limit Theorem by z k = ∑ t = k - R + 1 k - W - 1 A t ( G ( k - t ) - 1 ) + ∑ t = k - W k - r A t G ( k - t ) and will have a mean and variance of: μ = μ k = ∑ t = k - R + 1 k - W - 1 E ( A t ) ( G k - t - 1 ) + ∑ t = k - W k - r E ( A t ) G k - t = A _ ( ∑ t = W + 1 R - 1 ( G t - 1 ) + ∑ t = r W G t ) ( 13 ) σ 2 = σ k 2 = ∑ t = k - R + 1 k - W - 1 Var [ A t ( G k - t - 1 ) ] + ∑ t = k - W k - r Var [ A t G k - t ] = σ A 2 ( ∑ t = r W G t 2 + ∑ t = W + 1 R - 1 ( G t - 1 ) 2 ) ( 14 ) As noted above with respect to the constant daily arrival example, (I+Rk−nk−1) also has a normal distribution Φ (Series 2 in FIG. 2) with a mean of I+μ and a variance σ2. Because Ak is random in this example, the distribution of OTk is complicated. The distribution of OTk can be numerically calculated. The mean μOT can then be computed. [41] More particularly, assume that an arrival value Ak−W and an inventory value I + ∑ t = k - R + 1 k - W - 1 A t ( G k - t - 1 ) + ∑ t = k - W k - r A t G k - t are independent with their own respective distributions G and Φ, respectively. The distribution of the Max (·) term in OTk can then be numerically calculated as: ). Fmax(w)=G(w)+Φ(w)−G(w)·Φ(w) (15) By forcing w>0 in the above distribution and adding the mass probability in the tail to the probability at 0, the distribution of OT is obtained in the same manner as in the constant arrival case. If the variance in the random part arrivals Ak is low, it is possible to approximate the random arrival with a constant daily arrival term {overscore (A)}. The algorithm for constant arrival can then be used even where the arrivals are actually random. The examples above focus on optimizing inventory for a single part, but the inventive method can be applied for assets having multiple rotable parts without departing from the scope of the invention. Existing methods for constrained optimization problems can be applied to the inventive method to handle interrelations among rotable parts to find the optimal inventory for each part in the asset. The algorithm described above can be extended to calculate optimal rotable inventory levels for individual parts in a single asset. Given an expected service level for an asset, the algorithm can determine optimal service levels and inventory levels for individual parts to fulfill the expected service level for the entire asset. In this example, it is assumed that an asset has a total of I rotable parts, indexed as i=1, 2, . . . I. The expected service level for the entire asset is p. With the service levels for individual parts denoted as p1, p2, . . . pI, the following condition needs to be satisfied to meet the expected service level for the entire asset: ∐ I i = 1 p i ≥ p . ( 16 ) The left side of Equation 16 is the asset service level that is determined by the service levels of individual parts. As shown in previous examples, given a service level pi for a part i, the minimum rotable inventory can be computed for that part. More particularly, let xi represent the computed inventory level, and let A represent the relationship defined by the algorithm illustrated in previous examples. The computed inventory level xi can be expressed as: xi=A(pi) (17) Let ci be the cost for having one unit of part i in inventory. Thus, the total rotable inventory cost can be written as: J = ∑ i = 1 I x i · c i ( 18 ) The rotable inventory levels for individual part types within the asset can therefore be obtained by solving the constrained optimization problem defined by Equations 16, 17 and 18. That is: min J with J = ∑ i = 1 I x i · c i subject to ∐ i - 1 I p i ≥ p x i = 𝒜 ( p i ) , i = 1 , 2 , … I . p i ∈ ( 0 , 1 ] , i = 1 , 2 , … I . ( 19 ) With this constrained optimization problem defined, existing constrained optimization methods can be used to obtain the optimal rotable inventory levels for each part type in an asset to meet the customer service level for that asset. The minimum inventory value I* therefore reflects the optimum rotable inventory level for a given service level, a given repair arrival, and repair time statistic data. By generating a service level and checking whether the average service level meets a desired service level, it is possible to calculate the minimum rotable inventory level that can satisfy the desired service level. FIG. 4 is a block diagram of a computer system 200 that can be used to implement the method according to one embodiment of the invention. The system includes a user interface 202, a processor 204 that executes software that can carry out the inventive algorithm, and a memory 206 that stores data such as look-up tables, part type characteristic data, turnaround time information entered by the user, etc. The user interface 202 can be any system that allows a user to send data to and receive data from the processor 204, such as a keyboard/monitor combination, touch screen, graphical user interface, etc. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that the method and apparatus within the scope of these claims and their equivalents be covered thereby. | <SOH> BACKGROUND OF THE INVENTION <EOH>Many industries use repairable, or “rotable,” inventories for economic reasons. Rotable parts are different from “expendable” parts, which are parts having a low enough value that the repair of such parts does not make economic sense. Rather, such expendible parts are merely discarded and replaced with new parts. Rotable parts, by contrast, tend to be more expensive, making their repair and reinstallation, rather than simple replacement with a new part, more economically justifiable. Repairing a part or getting a new replacement can have uncertain lead times (i.e., the time interval between ordering a replacement and its delivery), and therefore rotable part inventories are used to bridge the gap between demand for the part and its supply as well as to maintain a selected high level of customer service. Due to the high cost of rotable parts, however, it is desirable to minimize the number of rotable parts held in inventory. But balancing minimal inventory with a desired customer service level (i.e., a measure of customer service defined as a ratio of parts delivered on time to the number of parts ordered) is difficult because the lead times for repairing parts and obtaining replacements are uncertain. Thus, there is a desire to calculate a minimum rotable inventory level that can satisfy a given customer service level. Currently-known attempts to create models solving this problem have not provided satisfactory solutions because they use deterministic methods that assume parts arrive into a repair shop and are repaired according to standard time distributions. In actual practice, however, arrivals and repair time are much more uncertain. Thus, current models for optimizing rotable inventory do not generate satisfactory solutions because they fail to take these uncertainties into account. Further, assets may contain multiple types of rotable parts and the asset service level is determined by the service levels of individual part types. The interrelationships between those part types make it more difficult to determine optimal inventory levels for individual part types to achieve a desired assert service level. Deterministic methods are unable to consider the interrelationships between the parts. There is a desire for a method that can calculate the optimum amount of rotable inventory needed to satisfy a given customer service level while taking these uncertainties into account. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention is directed to a method for conducting a repairable inventory analysis that calculates the minimum number of repairable parts to be held in inventory while still being able to satisfy the demand for spare parts even in view of uncertain repair lead times. Given a service level, which is defined as a total number of on-time delivered parts delivered by the total number of requested parts, one embodiment of the method uses a set of equations that relates the optimal rotable inventory level to a customer service level, given arbitrary probability distributions of a repair lead-time and a part arrival process. A search procedure is used to find the optimal rotable inventory level. In one embodiment, it is assumed that the number of parts requiring repair in a given time unit is constant and a part repair lead-time distribution is given. The mean and variance of the number of available parts at any time (or the amount of back orders, if the mean is negative) are computed. In this embodiment, this number is random and cab be proven to be normally distributed. A probability term that corresponds to a given probability level under a normal distribution is computed or looked up from a standard normal distribution table. The corresponding inventory level is computed from the probability term, the mean, and the variance. The number of on-time deliveries is then calculated based on its distribution, which is obtained by truncating the above-mentioned normal distribution with [0,A] and lumping the probability in each tail to the corresponding boundary. If the on-time delivery value is acceptably close to a desired on-time delivery value, the inventory level is deemed to be optimal and can meet desired customer service levels without having excessive, costly extra parts on hand. Otherwise, the probability level is updated following a search procedure, and the above calculation is repeated until the optimal inventory level is obtained. In another embodiment, it is assumed that the number of arriving parts in a given time unit is random. The algorithm described in the previous embodiment still applies, except that the distribution of on-time delivery is more complicated and difficult to obtain in a closed form. Equations for computing the above distribution numerically, and for computing the mean and variance of the number of available parts at any time, are provided. In another embodiment, an asset with multiple part types is analyzed. The asset service level is computed as the product of service levels of individual part types. With the above algorithm, inventory levels for individual part types can be obtained with given service levels, and the problem is formulated as finding the optimal service levels for individual part types. With known per-unit inventory costs, the optimization problem is formulated as minimizing total inventory cost, subject to the above service level relations, and the inventory-service level relationships for individual part types. | 20040123 | 20100112 | 20050811 | 61629.0 | 1 | ZARE, SCOTT A | ROTABLE INVENTORY CALCULATION METHOD | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,763,807 | ACCEPTED | Method and therapeutic/cosmetic topical compositions for the treatment of rosacea and skin erythema using a1-adrenoceptor agonists | The present invention is directed to the treatment of skin erythema as exhibited in rosacea and other conditions characterized by increased erythema (redness) of the skin. These conditions exhibit dilation of blood vessels due to a cutaneous vascular hyper-reactivity. In particular, the present invention is directed to a novel composition and method for the treatment of skin erythema using α1-adrenergic receptor (α1-adrenoceptor) agonists incorporated into cosmetic, pharmacological or dermatological compositions for topical application to the skin. | 1. A method for treating at least one condition selected from the group consisting of rosacea, acne, skin redness or other conditions characterized by discreet erythema of the skin in a subject in need of such treatment, comprising administering topically to said subject, for such period of time as is required to elicit the desired therapeutic response, a therapeutically or cosmetically effective amount of at least one alpha-1 adrenoreceptor agonist. 2. The method according to claim 1 wherein said, at least one alpha-1 agonist is topically applied to the skin. 3. The method according to claim 1, wherein said, the alpha-1 adrenoreceptor agonist comprises oxymetazoline. 4. The method according to claim 1, wherein said, the alpha-1 adrenoreceptor agonist comprises tetrahydrozoline. 5. The method according to claim 1, wherein said, the alpha-1 adrenoreceptor agonist comprises nephazoline. 6. The method according to claim 1, wherein said the alpha-1 adrenoreceptor agonist comprises xylometazoline. 7. The method according to claim 1, wherein the treated condition comprises rosacea. 8. The method according to claim 1, wherein the treated condition comprises acne. 9. The method according to claim 1, wherein the treated condition comprises sunburn. 10. The method according to claim 1, wherein the treated condition comprises chronic sun damage. 11. The method according to claim 1, wherein the treated condition comprises other discreet erythemas. 12. A composition for topical administration to the skin for treating rosacea comprising oxymetazoline HCl and an inert carrier. 13. The method according to claim 1, wherein at least one alpha-1 adrenoreceptor agonist is co-administered with a therapeutically effective amount of at least one other active agent selected from the group consisting of antibacterial agents, antiparasitic agents, antifungal agents, anti-inflammatory agents, antihistamines, anti-pruriginous agents, anesthetics, antiviral agents, keratolytic agents, anti free-radical agents, antiseborrheic agents, antidandruff agents, antiacne agents, sunscreens and sun blocking agents, and active agents which modify at least one of cutaneous differentiation, proliferation, and pigmentation. 14. The method according to claim 1, wherein said at least one alpha-1 adrenoreceptor agonist is administered in a pharmacologically or cosmetically acceptable form selected from the group consisting of solutions, gels, lotions creams, ointments, foams, emulsions, microemulsions, milks, serums, aerosols, sprays, dispersions, microcapsules, vesicles and microparticles thereof. 15. The method according to claim 1, wherein said at least one alpha-1 adrenoreceptor agonist is administered in a pharmacologically or cosmetically acceptable form selected from the group consisting of soaps and cleansing bars. 16. The method according to claim 1, wherein said skin redness, rosacea, or discreet erythema is elicited by at least one factor selected from the group consisting of intake of food, of hot or alcoholic drinks, temperature variations, heat, exposure to ultraviolet or infrared radiation, exposure to low relative humidity, exposure of the skin to strong winds or currents of air, exposure of the skin to surfactants, irritants, irritant dermatological topical agents, or cosmetics. 17. An acne and rosacea treatment composition comprises: an effective amount of an acne and rosacea treatment composition to treat acne, which composition includes: (a) An acne treatment medication selected from the group consisting of benzoyl peroxide and salicylic acid; (b) A vasoconstrictor selected from the group consisting of an alpha one adrenoreceptor agonist, and (c) An inert carrier, wherein, when said benzoyl peroxide is the acne treatment medication, it is in an amount of about 0.1% to about 20% based on the total weight of the composition, and when said salicylic acid is the acne treatment medication, it is in an amount of 0.05% to 15.0% based on the total weight of the composition; and, wherein said vasoconstrictor is in an amount of about 0.05% to about 20% by weight, based on the total weight of the composition. 18. The acne treatment composition of claim 17 wherein said acne treatment medication is benzoyl peroxide. 19. The acne treatment composition of claim 17 wherein said benzoyl peroxide is in an amount of about 1.0% to about 15% by total weight of the composition. 20. The acne treatment composition of claim 17 wherein said acne treatment medicine is salicylic acid. 21. The acne treatment composition of claim 17 wherein said salicylic acid is in an amount of about 0.1% to 10.0% by total weight of the composition. 22. The acne treatment composition of claim 17 wherein said alpha 1 vasoconstrictor is in a preferred amount of about 0.1% to about 10% by weight, based on the total weight of the composition. 23. The acne treatment composition of claim 17 wherein said vasoconstrictor is phenylephrine. 24. The acne treatment composition of claim 17 wherein said vasoconstrictor comprises oxymetazoline hydrochloride. | FIELD OF THE INVENTION The present invention is directed to the field of Rosacea and particularly to treatments for Rosacea. BACKGROUND OF THE INVENTION Rosacea is a chronic inflammatory disease associated with dilation of the facial blood vessels in humans. Rosacea affects the skin of the central face, especially the nose, cheeks, chin and forehead. The disease may progress with age. Rosacea may begin in individuals less than 20 years of age but peaks between the ages of 40 and 50. Early rosacea is characterized by recurrent episodes of flushing or blushing that often develop into persistent or permanent redness of the skin. Flushing may be triggered by numerous non-specific stimuli including sun exposure, heat, cold, alcoholic drinks, spicy foods, chemical irritation and strong emotions. With time, papules, pustules, blood vessel formation and hypertrophy of sebaceous glands may develop. Symptoms of facial discomfort can include tightness, itching, burning, warmth, stinging and/or tingling. Classically, treatment includes anti-infectious agents, such as, metronidazole, clindamycin, precipitated sulfur, sodium sulfacetamide, benzoyl peroxide, azelaic acid, or tetracycline-class antibiotics. But these agents do not affect the vascular component of this condition or the resulting skin redness. Other treatment strategies include avoidance of triggering factors, irritating stimuli, and limiting sun exposure. Lasers are now available to treat some of the telangiectasias and redness in rosacea. An excellent review of the currently available lasers is found in the article: Getting the Red Out, presented in the 6th Annual Acne and Rosacea issue of Skin & Aging, August 2003, pages 74-80. However, as is clearly stated in that review by Michael Krivda, “not all facial vessels respond to currently available laser therapies.” Furthermore, although some telangiectasias are treatable with laser, treatment of these blood vessels with medications has been completely ineffective. James Q. Del Rosso, DO, clinical assistant professor, Department of Dermatology, University of Nevada School of Medicine, Las Vegas, stated in: Medical Management of Rosacea with Topical Agents: A thorough appraisal of available treatment options and recent advances, Cosmetic Dermatology, August 2003: “Currently available medical therapies for rosacea have not been shown to reduce the number of facial telangiectasias.” Finally, there is currently no consistently effective treatment of any kind for the acute flushing and blushing of rosacea. John E. Wolf, Jr, MD, professor and chairman of the Department of Dermatology, Baylor College of Medicine, Houston, Tex., addressed this very issue in the meeting highlights for the Fall Clinical Dermatology Conference in Las Vegas, Nev., 2002. According to Dr. Wolf, “By far the most difficult-to-treat and challenging patients with rosacea are the patients who flush and blush. Indeed, no therapy works consistently in these patients.” Dr. Wolf further asserted, “In my opinion, lasers are the most effective treatment for erythemato-telangiectatic rosacea, but I think they are much less effective for flushing and blushing patients. Some patients will respond but most do not.” Similarly, no consistently effective treatment has existed for the redness that may develop in other forms of discreet skin erythemas particularly those due to vascular cutaneous hyper-reactivity, including the redness associated with acute sunburn, chronic solar damage, inflammatory acne, or emotionally or physiologically induced erythema. These conditions may also be accompanied by itching, burning, or pain with resulting significant irritation for individuals suffering therefrom. Thus, there exists a need for effective treatment of skin redness and of the state of vascular cutaneous hyper-reactivity as exhibited in rosacea or discreet erythemas. Although the cause of rosacea is still unknown, it is clear that individuals with this condition exhibit a cutaneous hyper-reactivity with dilation of blood vessels of the skin. An acute dilation of blood vessels leads to periodic episodes of flushing or blushing. The more chronic form, felt to be due to blood vessels dilating over decades and eventually remaining dilated permanently, manifests as permanent redness of the skin or fine visible blood vessel formation (telangiectasias) within the skin. A plethora of topical dermatological, cosmetic and pharmaceutical preparations and numerous methods and apparati exist for the treatment of rosacea, however, none has been proven consistently effective in treating and/or preventing the vascular dilatation which characterizes the erythema and flushing which are hallmarks of the disease. A number of patents have been issued related to rosacea treatments. U.S. Pat. No. 4,837,378 to Borgman, describes a topical aqueous gel containing metronidazole and polyacrylic acid for the treatment of rosacea. U.S. Pat. No. 6,174,534 to Richard et al. Claims the use of a cosmetic composition containing from 1-5% of a C.sub.12-C.sub.24 fatty acid, from 5 to 15% of an ester of C.sub.12-C.sub.24 fatty acid and of a C.sub.2-C.sub.3 polyalkylene oxide fragment containing from 2 to 100 polyalkylene oxide residues, from 1 to 20% of an optionally polyoxyalkylenated C.sub.12-C.sub.22 fatty acid glyceride containing from 0 to 20 ethylene oxide residues, from 1 to 20% of an ester of a C.sub.12-C.sub.24 fatty acid and of a C.sub.1-C.sub.6 alcohol, from 0.1 to 10% of glycerol, from 0.1 to 3% of a C.sub.12-C.sub.24 fatty alcohol and water, where the composition is free of metronidazole, lanthanide, tin, zinc, manganese, yttrium, cobalt, barium strontium salt, and non-photosynthetic filamentous bacteria. U.S. Pat. No. 5,972,993 describes a method of treating rosacea with a topically applied compound comprising an antioxidant (“free-radical scavenger”) mixed in an inert vehicle. U.S. Pat. No. 5,569,651, to Garrison, et al discusses the use of a combination of salicylic acid and lactic acid to treat the sensitive skin of rosacea. U.S. Pat. No. 5,438,073, to Saurat, et al claims the use of dermatological compositions containing retinoids for the treatment of rosacea. U.S. Pat. No. 6,180,699 to Tamarkin, et al claims the use of dermatological preparations containing mono or diesters of alpha, omega dicarboxylic acids for the treatment of the hyperkeratinization and seborrheic components of rosacea. U.S. Pat. No. 6,176,854 to Cone, claims the use of a Holmium laser system for the coagulation of some of the dilated blood vessels associated with rosacea to attempt to decrease the redness of the condition. U.S. Pat. No. 6,306,130 describes the use of a methods and apparati for heating and inducing necrosis and degradation of blood vessels with an external energy source (e.g. a laser) to permanently weld blood vessels and treat various conditions such as varicose veins and telangiectasias. Additionally, new insights and theories regarding the pathogenesis of rosacea have led to the development of treatment strategies focusing on the role of neurotransmitters and other potential mediators of vascular dilatation and hyper-reactivity. U.S. Pat. No. 5,958,432 to Breton, et al. describes the use of cosmetic/pharmaceutical compositions comprised of an effective Substance P antagonist of at least one beta-adrenergic agonist for the treatment of a variety of mammalian disorders mediated by an increase in the synthesis and/or release of Substance P including cutaneous disorders and sensitive skin and may generally relieve the irritation of rosacea (but has no direct vasoconstrictive properties). U.S. Pat. No. 5,932,215 to de Lacharriere et al. is directed to the development of therapeutic/cosmetic compositions comprising CGRP (calcitonin gene related peptide) antagonists, Substance P antagonists, for treating skin redness, rosacea and discrete erythema afflicting a mammalian, notably human patient. Individuals are treated by administrating a therapeutically/cosmetically effective amount of at least one CGRP antagonist, advantageously in combinatory mixture with at least one antagonist of a neuropeptide other than CGRP, e.g., a substance P antagonist, and/or at least one inflammation mediator antagonist. The notion of administering alpha-2 adrenoceptor agonists to alleviate the symptoms of diseases modulated by activity of these receptors has been investigated. U.S. Pat. No. 5,916,900 to Cupps, et al. relates to the use of certain substituted 7-(2-imidazolinylamino)quinolone compounds which have been found to be alpha-2 adrenoreceptor agonists and are useful for the treatment of disorders modulated by alpha-2 adrenoceptors. Such disorders include sinusitis, nasal congestion, numerous pulmonary and cardiovascular disorders, gastrointestinal disorders such as diarrhea, irritable bowel syndrome and peptic ulcer, conditions associated with chronic pain, migraine, and substance-abuse withdrawal syndrome. The subject invention involved novel compounds and compositions which have activity when administered perorally, parenterally, intranasaly and/or topically. Finally, α1-adrenoceptor agonists have been historically used on ocular mucosal tissue to treat the conjunctival redness associated with allergic and other conditions, and to nasal mucosa as a decongestant for the treatment of allergic rhinitis and other conditions. Also, U.S. Pat. No. 6,136,337 provides a composition for rectal mucosal administration suitable for curing hemorrhoids which includes an acrylic acid polymer, a vasoconstrictor, including tetrahydrozoline hydrochloride, naphazoline hydrochloride, phenylepherine hydrochloride or oxymetazoline hydrochloride and a rectal tissue-curing agent. Critical to understanding the effects of catecholamines and related sympathomimetic agents is an understanding of the classification and properties of the different types of adrenergic receptors (adrenoceptors) that mediate their response. Although structurally related, different adrenoceptors regulate distinct physiological processes by controlling the synthesis or release of a variety of second messenger chemicals or compounds. Additional general references of interest are set forth below. Cross, E. Transdermal penetration of vasoconstrictors-present understanding and assessment of the human epidermal flux and retention of free bases and ion-pairs. Pharm Res. 2003 February; 20(2): 270-4. Daly, CJ et al. Cellular Localization and Pharmacological Characterization of Functioning Alpha-1 Adrenoceptors by Fluorescent Ligand Binding and Image Analysis Reveals Identical Binding Properties of Clustered and Diffuse Populations of Receptors. Pharmacology and Experimental Therapeutics. 1998; 286(2): 984-990. Del Rosso, JQ. Medical Management of Rosacea With Topical Agents: A Thorough Appraisal of Available Treatment Options and Recent Advances. Cosmetic Dermatology. 2003; 16(8): 47-55. Hoffman B: Catecholamines, Sympathomimetic Drugs, and Adrenergic Receptor Antagonists, in Goodman & Gilman's The Pharmacological Basis of Therapeutics, Tenth Edition, edited by Hardman J and Limbird L. New York, N.Y., McGraw-Hill, 2001, pp. 215-249. Hoffman B and Taylor P: Neurotransmission: The Autonomic and Somatic Motor Nervous Systems, in Goodman & Gilman's The Pharmacological Basis of Therapeutics, Tenth Edition, edited by Hardman J and Limbird L. New York, N.Y., McGraw-Hill, 2001, pp. 129-153. Hudson, AL et al. In vitro and in vivo approaches to the characterization of the alpha2-adrenoceptor. J Auton Pharmacol. 1999 December; 19(6): 11-20. Krivda, M. Getting the Red Out. Skin & Aging. 6th Annual Acne & Rosacea Issue. 2003; 11(8): 74-80. Odom RB et al. Andrews' Diseases of the Skin, Ninth Edition, Philadelphia, W. B. Saunders, 2000, pp 301-303. Plewig, G et al: Rosacea, in Fitzpatrick's Dermatology in General Medicine, Fifth Edition, edited by Irwin Freedberg et al. New York, N.Y., McGraw-Hill, 1999, pp 785-794. Wolf J. ‘Toughest Patients’ May Be the Ones You See Each Day. in Meeting Highlights: 21st Anniversary Fall Clinical Dermatology Conference, Las Vegas, Nev., 2002: p. 1-4. α-Adrenoceptor Subtypes Initially classified as either α or β subtype receptors, based on anatomical location and functional considerations, more recent pharmacological and molecular biological techniques have identified the heterogeneity of the receptors and led to the identification of numerous subtypes of each receptor. α-adrenoceptors exist on peripheral sympathetic nerve terminals and are divided into two subtypes, α1 and α2. α1 is found mostly postsynaptically, while α2, although typically sited presynaptically, can also occur postsynaptically. These initial subtypes were further divided into α1A, α1B and α1D receptors (by pharmacological methods), each with distinct sequences and tissue distributions, and α1a, α1b, and α1d by molecular biological and cloning techniques (note lower case letters refer to cloned receptors). Similarly, work done to identify subtypes of the α2 adrenoeceptor has led to the discovery of a subclasses α2A, α2B, α2C, α2D, and α2C10. α1-Adrenoceptor Location and Function α1-adrenoceptors are found both in the central and peripheral nervous system. In the Central Nervous System they are found mostly postsynaptically and have an excitatory function. Peripherally, they are responsible for contraction and are situated on vascular and non-vascular smooth muscle. α1-adrenoceptors on vascular smooth muscle are located intrasynaptically and function in response to neurotransmitter release. For non-vascular smooth muscle, they can be found on the liver, where they cause hepatic glycogenolysis and potassium release. On heart muscle they mediate a stimulatory (positive inotropic) effect. In the gastrointestinal system they cause relaxation of gastrointestinal smooth muscle and decrease salivary secretion. Transduction Mechanisms All α-adrenoceptors use G-proteins as their transduction mechanism. Differences occur in the type of G-protein the receptors are coupled to. α1-adrenoceptors are coupled through the Gp/Gq mechanism, whereas α2-adrenoceptors are coupled through different G-proteins. Gp/Gq activates phospholipase C that phosphorolates phosphatidyl inositol to produce inositol triphosphate and diacylglycerol. These compounds act as second messengers and cause release of calcium from intracellular stores in the sarcoplasmic reticulum, and activation of calcium channels respectively. They thus produce their effects by the release of calcium from intracellular stores. Clinical Uses The clinical uses of adrenergic compounds are vast. The treatment of many medical conditions can be attributed to the action of drugs acting on adrenergic receptors. For example, α-adrenoceptor ligands can be used in the treatment of hypertension. Drugs such as prazosin, an α1-adrenoceptor antagonist and clonidine, an α2-adrenoceptor agonist both have antihypertensive effects. α1-adrenoceptor antagonists are also employed in the treatment of benign prostatic hypertrophy. Several sympathomimetic drugs are used primarily as vasoconstrictors for local application to nasal and ocular mucous membranes (see Table 1). α-adrenoceptor agonists are used extensively as nasal decongestants in patients with allergic or vasomotor rhinitis and in acute rhinitis in patients with upper respiratory infections (EMPEY and MEDDER, 1981). These drugs probably decrease the resistance to airflow by decreasing the volume of the nasal mucosa. The receptors that mediate this effect appear to be the α1-adrenoceptors, though α2-adrenoceptors may be responsible for contraction of arterioles that supply the nasal mucosa. While a major limitation of therapy with nasal decongestants is that of a loss of efficacy with prolonged use, agonists that are selective for α1 receptors may be less likely to induce mucosal damage (DEBERNARDIS et al 1987). As an ocular decongestant, to decrease swelling and redness of the eyes, α-adrenoceptor agonists are widely used in the treatment of allergic conjunctivitis, whether seasonal (‘hay fever’) or perennial. The use of a topically applied α1-adrenoceptor agonist preparation to the skin, however, is hitherto unknown to this art and would be desirable to provide a method of treating skin affected by rosacea or other conditions of increased cutaneous erythema. TABLE 1 Characterisation of α-adrenoceptors: Receptor Type α1 α2 Selective Phenylephrine Clonidine Agonist Oxymetazoline Clenbuterol Selective Doxazosin Yohimbine Antagonist Prazosin Idazoxan Agonist A = NA >> ISO A = NA >> ISO Potency Order Second PLC dec. cAMP via Messengers activation via Gi/o causes dec. and Effectors Gp/q causes [Ca2+]i inc. [Ca2+]i Physiological Smooth Inhibition of Effect muscle transmitter contraction release Hypotension, anaesthesia, Vasoconstriction Link to IUPHAR nomenclature: alpha-1 table or alpha-2 table SUMMARY OF THE INVENTION α1-adrenoceptor agonist have been used to constrict blood vessels or minimize redness on ocular mucosal tissue to treat conjunctival redness, to nasal mucosa, as a decongestant for the treatment of allergic rhinitis, and for rectal mucosal administration suitable for curing hemorrhoids. However, to date it was not envisaged to use α1-adrenoceptor agonists for treating skin redness. It has now been observed that α1-adrenoceptor agonists are useful for eliciting a preventive and/or therapeutic effect on decreasing skin redness when applied topically to the skin. Accordingly, it is an object of the present invention to provide a novel method for treating rosacea and other conditions of the skin characterized by increased erythema (redness). Another object of the present invention to provide novel topical compositions for treating rosacea and other conditions of the skin characterized by increased erythema (redness). It is another and more specific object of the present invention to provide such compositions that include the formulation of at least one α1-adrenoceptor agonist into a cosmetic, pharmaceutical or dermatological composition for decreasing and/or preventing skin redness and irritation as exhibited in rosacea or other conditions of the skin characterized by increased erythema and to administer said compositions to a mammal, notably a human, in order to treat or prevent the disease states indicated above. Additionally, it is an object of the present invention to provide such compositions that include the formulation of at least one α1-adrenoceptor agonist into a cosmetic, pharmaceutical or dermatological composition for decreasing and/or preventing skin redness and irritation as exhibited in rosacea or other conditions of the skin characterized by increased erythema in combination and admixed with other agents known to be effective in treating other manifestations of said skin conditions and to administer said compositions to a mammal, notably a human, in order to treat or prevent the manifestations of the disease states indicated above. The present invention is achieved by the provision of methods of treating rosacea or other conditions of the skin characterized by increased erythema, in a patient in need of such treatment, comprising the topical administration of a therapeutically effective amount of a composition comprising at least one α1-adrenoceptor agonist. α1-adrenoceptor agonists include, but are not limited to, oxymetazoline hydrochloride, tetrahydrozoline hydrochloride, naphazoline hydrochloride and phenylepherine hydrochloride. Preferably, the composition comprises at least one α1-adrenoceptor agonist formulated in a pharmaceutically/dermatologically acceptable medium, preferably a gel, cream, lotion or solution which is preferably administered by spreading the gel, cream, lotion or solution onto the affected area. Preferred embodiments may also include enhancers of cutaneous penetration or inhibitors or regulators of cutaneous penetration as required to increase therapeutic efficacy and/or decrease systemic absorption and any potential undesirable systemic effects of the active agent(s). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention is based at least in part on the clinical observation that the topical application of a therapeutically effective amount of a composition comprising at least one α1-adrenoceptor agonist to the skin is effective in significantly reducing or preventing the redness (erythema), flushing and sensation of warmth and discomfort which are hallmarks of rosacea and other conditions causing discreet erythema of the skin (e.g. acne, sunburn), and thus provides both subjective and objective relief of signs and symptoms of these conditions. Prototypical α1-adrenoceptor agonists include phenylepherine and oxymetazoline, but other α1-adrenoceptor agonist agents include, but are not limited to naturally occurring and synthetically derived compounds based on or derived from pharmacologically similarly acting chemicals, drugs or prodrugs and derivatives thereof. Examples of preferred compounds which are specifically contemplated as α1-adrenoceptor agonists suitable for use in accordance with the present invention include, but are not limit to e.g., the α1-adrenoceptor agonists oxymetazoline, tetrahydrozoline, nephazoline, xylometazoline and the α1-adrenoceptor agonists discussed in chapters 6 and 10 of Goodman and Gilman's The Pharmacological Basis of Therapeutics, Tenth Edition, edited by Hardman J and Limbird L. New York, N.Y., McGraw-Hill, 2001, which is hereby incorporated by reference as though set forth in full herein, and in particular phenylepherine methoxamine, mephentermine, metaraminol, desglymidodrine, and its prodrug midodrine. As no prior consideration of the application of α1-adrenoceptor agonist to the skin has been contemplated or reported, for any indication, little is known of the cutaneous absorption or toxicology of oxymetazoline used in this fashion. The manufacturers report no significant organ damage or general toxicity in dog, cat, rabbit or mouse about dosages close to those used in man. When administered by injection subcutaneously, in rabbits, no drug related abnormalities or effects on the offspring were found. In a retrospective study in man, no association was found between the drug and congenital disorders. No carcinogenicity tests have been reported. But oxymetazoline has been used intranasaly and ophthalmicaly for decades for reducing blood flow and diminishing of swelling of the mucosa and has not been reported to effect any systemic side effects. There is no formal data on the subject, however. The excellent safety and efficacy profile of oxymetazoline when used intranasaly or ophthalmicaly to effect local vasoconstriction suggested its potential use as a topically applied vasoconstrictor to the skin for the treatment of the erythema and telangiectasias of rosacea and other erythematous conditions of the skin and has been observed clinically by one of the applicants in his clinical practice of dermatology. The local anti-erythema effect is thus observed when topically applying an effective amount of an α1-adrenoceptor agonist, admixed with a skin-specific penetration enhancer and a pharmacologically acceptable vehicle for topical administration without causing any noticeable systemic effects. The clinical efficacy of the applied α1-adrenoceptor agonist compound is predicated not only upon the agent reaching the receptors, which are located within the skin on vascular smooth muscle, but also on the pharmacokinetics of each particular receptor agonist. Thus the choice and concentration of the active agent, or combination of active agents, the topical delivery system and vehicle for the active agent(s) are significant considerations. Specifically, prototypical α1-adrenoceptor agonists in the present invention are tetrahydrozoline and oxymetazoline, and when included in the typical embodiment as the sole active ingredient (sole α1-adrenoceptor agonist) are preferably used in amounts of about 0.05% up to about 30%, and preferably about 0.001% up to about 3% by weight based on the total weight of the composition. Where both, or an additional or different α1-adrenoceptor agonist is admixed, lower amounts of the active compound(s) might be included. Additionally, the carrier or vehicle of the invention will have dramatic effects on the concentrations of the active ingredients selected. The preferred embodiments employ active ingredients in amounts effective to achieve clinical efficacy without causing systemic side effects. The compositions according to the invention may comprise all pharmaceutical forms normally utilized for the topical route of administration and known to practitioners of this art including solutions, gels, lotions creams, ointments, foams, mousses, emulsions, microemulsions, milks, serums, aerosols, sprays, dispersions, microcapsules, vesicles and microparticles thereof. The subject compositions may also be formulated as solid preparations constituting soaps or cleansing bars. These compositions are formulated according to conventional techniques. The term “pharmacologically/dermatologically acceptable carriers”, as used herein, means that the carrier is suitable for topical application to the keratinous tissue, has good aesthetic properties, is compatible with the active agents of the present invention and any other components, and will not cause any untoward safety or toxicity concerns. The carrier can be in a wide variety of forms. For example, emulsion carriers, including, but not limited to, oil-in-water, water-in-oil, water-in-oil-in-water, and oil-in-water-in-silicon emulsions, are useful herein. As will be understood by the skilled artisan, a given component will distribute primarily into either the water or oil/silicon phase, depending on the water solubility/dispersibility of the component in the composition. A safe and effective amount of carrier is from about 50% to about 99.999%, more preferably from about 70% to about 99.99%. The composition, if desired, can contain various known bases such as excipients, binders, lubricants, and disintegrants. If desired, it can also contain oily materials such as various fats, oils, waxes, hydrocarbons, fatty acids, higher alcohols, ester oils, metallic soaps, animal or vegetable extracts, hydrophilic or lipophilic gelling agents, hydrophilic or lipophilic active agents, pharmaceutically effective components such as vitamins, hormones, amino acids, surfactants, colorants, dyes, pigments, fragrances, odor absorbers, antiseptics, preservatives, bactericides, humectants, thickeners, solvents, fillers, antioxidants, sequestering agents, sunscreens, or any other known components and additives as long as the effects of the present invention are not impaired. Examples of suitable oils includes mineral oils, plant oils such as peanut oil, sesame oil, soybean oil, safflower oil, sunflower oil, animal oils such as lanolin or perhydrosqualene, synthetic oils such as purcellin oil, silicone oils such as cyclomethicome among others. Fatty alcohols, fatty acids such as stearic acid and waxes such as paraffin wax, carnauba wax or beeswax may also be used as fats. The composition may also contain emulsifying agents such as glyceryl stearate, solvents such as lower alcohols including ethanol, isopropanol, and propylene glycol, hydrophilic gelling agents including carboxyvinyl polymers or acrylic copolymers, polyacrylamides, polysaccharides, lipophilic gelling agents or fatty acid metal salts among others, hydrophilic acting agents such as amino acids, sugars, starch or urea, lipophilic active agents such as retinol or tocopherol. In some embodiments, the compositions contain one or more α1-adrenoceptor agonists, to act specifically on the erythematous component of the condition to be treated, admixed with another agent known to be effective in treating another manifestation of the disease state. For example, compositions consisting of anti-rosacea agents such as metronidazole, precipitated sulfur, sodium sulfacetamide, or azelaic acid, which are commonly used to treat the papular and pustular components of rosacea are combined with a dermatologically/pharmacologically acceptable form of the subject α1-adrenoceptor agonist to effect treatment of both the inflammatory (papular and pustular) and erythematous manifestations of the condition. There is currently no known composition available that succeeds in this goal. Other embodiments combine one or more α1-adrenoceptor agonist with active agents destined, in particular, for preventing and/or treating the erythema associated with numerous other skin complaints, conditions and afflictions. Examples of these agents include: 1. Antirosacea agents such as metronidazole, precipitated sulfur, sodium sulfacetamide, or azelaic acid. 2. Antibacterial agents (antibiotics) such as clindamycin phosphate, erythromycin, or antibiotics from the tetracycline family. 3. Antimycobacterial agents such as dapsone. 4. Other antiacne agents such as retinoids, or benzoyl peroxide. 5. Antiparasitic agents such as metronidazole, permethrin, crotamiton or pyrethroids. 6. Antifungal agents such as compounds of the imidazole family such as miconazole, clotrimazole, econazole, ketoconazole, or salts thereof, polyene compounds such as amphotericin B, compound of the allylamine family such as terbinafine. 7. Steroidal anti-inflammatory agents such as hydrocortisone triamcinolone, fluocinonide, betamethasone valerate or clobetasol propionate, or non-steroidal anti-inflammatory agents such as ibuprofen and salts thereof, naproxen and salts thereof, or acetaminophen. 8. Anesthetic agents such as lidocaine, prilocaine, tetracaine, Hydrochloride and derivatives thereof. 9. Antipruriginous agents such as thenaldine, trimeprazine, or pramoxine. 10. Antiviral agents such as acyclovir. 11. Keratolytic agents such as alpha- and beta-hydroxy acids such as glycolic acid or salicylic acid, or urea. 12. Anti-free radical agents (antioxidants) such as Vitamin E (alpha tocopherol) and its derivatives, Vitamin C (ascorbic acid), Vitamin A (retinol) and its derivatives, and superoxide dismutases. 13. Antiseborrheic agents such as zinc pyrithione and selenium sulfide. 14. Antihistamines such as cyproheptadine or hydroxyzine. 15. Tricyclic antidepressants such as doxepin hydrochloride. In order to further illustrate the present invention and the advantages thereof, the following specific examples are given, it being understood that the same are illustrative and in no ways limitative. The administration of compositions containing one or more alpha-1 adrenoreceptor agonists elicits a marked decrease or even complete disappearance of skin redness, which is manifested both in rosacea and other discreet erythemas. Specifically, according to the present invention, at least one alpha-1 adrenoreceptor agonist is formulated into a cosmetic, pharmaceutical or dermatological composition for treating skin redness of vascular origin, evident in rosacea and/or other discreet erythemas including acne and sunburn. The compositions of the invention will be, preferably, administered topically. The subjective compositions for topical application comprise a cosmetically, pharmaceutically or dermatologically acceptable medium (vehicle, diluent or carrier), namely a medium which is compatible with application to the skin. The present invention is directed to the use of alpha 1 and 2 adrenoreceptor agonists for treat rosacea or erythema. In one embodiment, the invention is directed to the use alpha 1 agonists such oxymetazoline hydrochloride as a vasoconstrictor for use with or without an anti-acne compound. Alternative alpha 1 agonists including Phenylephrine are applicable to the teachings of the present invention. The principles of the present invention are also deemed to be applicable to alpha 2 adrenoreceptor agonists such as Clonidine and Clenbuterol. For the purposes of this disclosure, rosacea is characterized by erythema of the face, predominantly on the cheeks, the forehead and the nose, hyperseborrhoea of the face on the forehead, the nose and the cheeks, and an infectious component manifesting acne form pustules. Moreover, these indications are associated with a neurogenic component, namely, a cutaneous hyperreactivity of the skin of the face and of the neck, characterized by the appearance of redness and subjective sensations of the itching or pruritus type, sensations of burning or of heating, sensations of stinging, tingling, discomfort, tightness, etc. The preferred alpha 1 or 2 agonist used as a vasoconstrictor in the present invention is preferably used in an amount of about 0.01% up to about 20%, and preferably about 0.1% to about 10%, by weight based on the total weight of the composition. In the most preferred embodiment, the vasoconstrictor comprises an alpha 1 or alpha 2 adrenoreceptor agonist. The vasoconstrictor used in the present invention may function to remove the redness from acne areas of the skin, including oxymetazoline hydrochloride, the preferred agonist in the present invention oxymetazoline hydrochloride: The chemical formula for oxymetazoline hydrochloride is as follows: 2-(3-Hydroxy-2,6-dimethyl-4-t-butylbenzyl)-2-imidazoline hydrochloride Oxymetazoline hydrochloride: Structural Formula: The following table sets forth the characteristics of alpha 1 and alpa 2 adrenoreceptors as used in the present invnetion. Receptor Type □1 □2 Selective Phenylephrine Clonidine Agonist Oxymetazoline Clenbuterol Selective Doxazosin Yohimbine Antagonist Prazosin Idazoxan Agonist A = NA >> ISO A = NA >> ISO Potency Order Second PLC activation dec. cAMP via Messengers via Gp/q Gi/o causes dec. and Effectors causes inc. [Ca2+]i [Ca2+]i Physiological Smooth Inhibition of Effect muscle transmitter contraction release Hypotension, anaesthesia, vasoconstriction The present invention has been described with reference to the enclosed preferred embodiment. The true nature and scope of the present invention is to be determined with reference to the claims appended hereto. | <SOH> BACKGROUND OF THE INVENTION <EOH>Rosacea is a chronic inflammatory disease associated with dilation of the facial blood vessels in humans. Rosacea affects the skin of the central face, especially the nose, cheeks, chin and forehead. The disease may progress with age. Rosacea may begin in individuals less than 20 years of age but peaks between the ages of 40 and 50. Early rosacea is characterized by recurrent episodes of flushing or blushing that often develop into persistent or permanent redness of the skin. Flushing may be triggered by numerous non-specific stimuli including sun exposure, heat, cold, alcoholic drinks, spicy foods, chemical irritation and strong emotions. With time, papules, pustules, blood vessel formation and hypertrophy of sebaceous glands may develop. Symptoms of facial discomfort can include tightness, itching, burning, warmth, stinging and/or tingling. Classically, treatment includes anti-infectious agents, such as, metronidazole, clindamycin, precipitated sulfur, sodium sulfacetamide, benzoyl peroxide, azelaic acid, or tetracycline-class antibiotics. But these agents do not affect the vascular component of this condition or the resulting skin redness. Other treatment strategies include avoidance of triggering factors, irritating stimuli, and limiting sun exposure. Lasers are now available to treat some of the telangiectasias and redness in rosacea. An excellent review of the currently available lasers is found in the article: Getting the Red Out, presented in the 6 th Annual Acne and Rosacea issue of Skin & Aging, August 2003, pages 74-80. However, as is clearly stated in that review by Michael Krivda, “not all facial vessels respond to currently available laser therapies.” Furthermore, although some telangiectasias are treatable with laser, treatment of these blood vessels with medications has been completely ineffective. James Q. Del Rosso, DO, clinical assistant professor, Department of Dermatology, University of Nevada School of Medicine, Las Vegas, stated in: Medical Management of Rosacea with Topical Agents: A thorough appraisal of available treatment options and recent advances, Cosmetic Dermatology, August 2003: “Currently available medical therapies for rosacea have not been shown to reduce the number of facial telangiectasias.” Finally, there is currently no consistently effective treatment of any kind for the acute flushing and blushing of rosacea. John E. Wolf, Jr, MD, professor and chairman of the Department of Dermatology, Baylor College of Medicine, Houston, Tex., addressed this very issue in the meeting highlights for the Fall Clinical Dermatology Conference in Las Vegas, Nev., 2002. According to Dr. Wolf, “By far the most difficult-to-treat and challenging patients with rosacea are the patients who flush and blush. Indeed, no therapy works consistently in these patients.” Dr. Wolf further asserted, “In my opinion, lasers are the most effective treatment for erythemato-telangiectatic rosacea, but I think they are much less effective for flushing and blushing patients. Some patients will respond but most do not.” Similarly, no consistently effective treatment has existed for the redness that may develop in other forms of discreet skin erythemas particularly those due to vascular cutaneous hyper-reactivity, including the redness associated with acute sunburn, chronic solar damage, inflammatory acne, or emotionally or physiologically induced erythema. These conditions may also be accompanied by itching, burning, or pain with resulting significant irritation for individuals suffering therefrom. Thus, there exists a need for effective treatment of skin redness and of the state of vascular cutaneous hyper-reactivity as exhibited in rosacea or discreet erythemas. Although the cause of rosacea is still unknown, it is clear that individuals with this condition exhibit a cutaneous hyper-reactivity with dilation of blood vessels of the skin. An acute dilation of blood vessels leads to periodic episodes of flushing or blushing. The more chronic form, felt to be due to blood vessels dilating over decades and eventually remaining dilated permanently, manifests as permanent redness of the skin or fine visible blood vessel formation (telangiectasias) within the skin. A plethora of topical dermatological, cosmetic and pharmaceutical preparations and numerous methods and apparati exist for the treatment of rosacea, however, none has been proven consistently effective in treating and/or preventing the vascular dilatation which characterizes the erythema and flushing which are hallmarks of the disease. A number of patents have been issued related to rosacea treatments. U.S. Pat. No. 4,837,378 to Borgman, describes a topical aqueous gel containing metronidazole and polyacrylic acid for the treatment of rosacea. U.S. Pat. No. 6,174,534 to Richard et al. Claims the use of a cosmetic composition containing from 1-5% of a C.sub.12-C.sub.24 fatty acid, from 5 to 15% of an ester of C.sub.12-C.sub.24 fatty acid and of a C.sub.2-C.sub.3 polyalkylene oxide fragment containing from 2 to 100 polyalkylene oxide residues, from 1 to 20% of an optionally polyoxyalkylenated C.sub.12-C.sub.22 fatty acid glyceride containing from 0 to 20 ethylene oxide residues, from 1 to 20% of an ester of a C.sub.12-C.sub.24 fatty acid and of a C.sub.1-C.sub.6 alcohol, from 0.1 to 10% of glycerol, from 0.1 to 3% of a C.sub.12-C.sub.24 fatty alcohol and water, where the composition is free of metronidazole, lanthanide, tin, zinc, manganese, yttrium, cobalt, barium strontium salt, and non-photosynthetic filamentous bacteria. U.S. Pat. No. 5,972,993 describes a method of treating rosacea with a topically applied compound comprising an antioxidant (“free-radical scavenger”) mixed in an inert vehicle. U.S. Pat. No. 5,569,651, to Garrison, et al discusses the use of a combination of salicylic acid and lactic acid to treat the sensitive skin of rosacea. U.S. Pat. No. 5,438,073, to Saurat, et al claims the use of dermatological compositions containing retinoids for the treatment of rosacea. U.S. Pat. No. 6,180,699 to Tamarkin, et al claims the use of dermatological preparations containing mono or diesters of alpha, omega dicarboxylic acids for the treatment of the hyperkeratinization and seborrheic components of rosacea. U.S. Pat. No. 6,176,854 to Cone, claims the use of a Holmium laser system for the coagulation of some of the dilated blood vessels associated with rosacea to attempt to decrease the redness of the condition. U.S. Pat. No. 6,306,130 describes the use of a methods and apparati for heating and inducing necrosis and degradation of blood vessels with an external energy source (e.g. a laser) to permanently weld blood vessels and treat various conditions such as varicose veins and telangiectasias. Additionally, new insights and theories regarding the pathogenesis of rosacea have led to the development of treatment strategies focusing on the role of neurotransmitters and other potential mediators of vascular dilatation and hyper-reactivity. U.S. Pat. No. 5,958,432 to Breton, et al. describes the use of cosmetic/pharmaceutical compositions comprised of an effective Substance P antagonist of at least one beta-adrenergic agonist for the treatment of a variety of mammalian disorders mediated by an increase in the synthesis and/or release of Substance P including cutaneous disorders and sensitive skin and may generally relieve the irritation of rosacea (but has no direct vasoconstrictive properties). U.S. Pat. No. 5,932,215 to de Lacharriere et al. is directed to the development of therapeutic/cosmetic compositions comprising CGRP (calcitonin gene related peptide) antagonists, Substance P antagonists, for treating skin redness, rosacea and discrete erythema afflicting a mammalian, notably human patient. Individuals are treated by administrating a therapeutically/cosmetically effective amount of at least one CGRP antagonist, advantageously in combinatory mixture with at least one antagonist of a neuropeptide other than CGRP, e.g., a substance P antagonist, and/or at least one inflammation mediator antagonist. The notion of administering alpha-2 adrenoceptor agonists to alleviate the symptoms of diseases modulated by activity of these receptors has been investigated. U.S. Pat. No. 5,916,900 to Cupps, et al. relates to the use of certain substituted 7-(2-imidazolinylamino)quinolone compounds which have been found to be alpha-2 adrenoreceptor agonists and are useful for the treatment of disorders modulated by alpha-2 adrenoceptors. Such disorders include sinusitis, nasal congestion, numerous pulmonary and cardiovascular disorders, gastrointestinal disorders such as diarrhea, irritable bowel syndrome and peptic ulcer, conditions associated with chronic pain, migraine, and substance-abuse withdrawal syndrome. The subject invention involved novel compounds and compositions which have activity when administered perorally, parenterally, intranasaly and/or topically. Finally, α 1 -adrenoceptor agonists have been historically used on ocular mucosal tissue to treat the conjunctival redness associated with allergic and other conditions, and to nasal mucosa as a decongestant for the treatment of allergic rhinitis and other conditions. Also, U.S. Pat. No. 6,136,337 provides a composition for rectal mucosal administration suitable for curing hemorrhoids which includes an acrylic acid polymer, a vasoconstrictor, including tetrahydrozoline hydrochloride, naphazoline hydrochloride, phenylepherine hydrochloride or oxymetazoline hydrochloride and a rectal tissue-curing agent. Critical to understanding the effects of catecholamines and related sympathomimetic agents is an understanding of the classification and properties of the different types of adrenergic receptors (adrenoceptors) that mediate their response. Although structurally related, different adrenoceptors regulate distinct physiological processes by controlling the synthesis or release of a variety of second messenger chemicals or compounds. Additional general references of interest are set forth below. Cross, E. Transdermal penetration of vasoconstrictors-present understanding and assessment of the human epidermal flux and retention of free bases and ion-pairs. Pharm Res. 2003 February; 20(2): 270-4. Daly, CJ et al. Cellular Localization and Pharmacological Characterization of Functioning Alpha-1 Adrenoceptors by Fluorescent Ligand Binding and Image Analysis Reveals Identical Binding Properties of Clustered and Diffuse Populations of Receptors. Pharmacology and Experimental Therapeutics. 1998; 286(2): 984-990. Del Rosso, JQ. Medical Management of Rosacea With Topical Agents: A Thorough Appraisal of Available Treatment Options and Recent Advances. Cosmetic Dermatology. 2003; 16(8): 47-55. Hoffman B: Catecholamines, Sympathomimetic Drugs, and Adrenergic Receptor Antagonists, in Goodman & Gilman's The Pharmacological Basis of Therapeutics, Tenth Edition , edited by Hardman J and Limbird L. New York, N.Y., McGraw-Hill, 2001, pp. 215-249. Hoffman B and Taylor P: Neurotransmission: The Autonomic and Somatic Motor Nervous Systems, in Goodman & Gilman's The Pharmacological Basis of Therapeutics, Tenth Edition , edited by Hardman J and Limbird L. New York, N.Y., McGraw-Hill, 2001, pp. 129-153. Hudson, AL et al. In vitro and in vivo approaches to the characterization of the alpha2-adrenoceptor. J Auton Pharmacol. 1999 December; 19(6): 11-20. Krivda, M. Getting the Red Out. Skin & Aging. 6 th Annual Acne & Rosacea Issue. 2003; 11(8): 74-80. Odom RB et al. Andrews' Diseases of the Skin, Ninth Edition , Philadelphia, W. B. Saunders, 2000, pp 301-303. Plewig, G et al: Rosacea, in Fitzpatrick's Dermatology in General Medicine, Fifth Edition , edited by Irwin Freedberg et al. New York, N.Y., McGraw-Hill, 1999, pp 785-794. Wolf J. ‘Toughest Patients’ May Be the Ones You See Each Day. in Meeting Highlights: 21 st Anniversary Fall Clinical Dermatology Conference, Las Vegas, Nev., 2002: p. 1-4. | <SOH> SUMMARY OF THE INVENTION <EOH>α 1 -adrenoceptor agonist have been used to constrict blood vessels or minimize redness on ocular mucosal tissue to treat conjunctival redness, to nasal mucosa, as a decongestant for the treatment of allergic rhinitis, and for rectal mucosal administration suitable for curing hemorrhoids. However, to date it was not envisaged to use α 1 -adrenoceptor agonists for treating skin redness. It has now been observed that α 1 -adrenoceptor agonists are useful for eliciting a preventive and/or therapeutic effect on decreasing skin redness when applied topically to the skin. Accordingly, it is an object of the present invention to provide a novel method for treating rosacea and other conditions of the skin characterized by increased erythema (redness). Another object of the present invention to provide novel topical compositions for treating rosacea and other conditions of the skin characterized by increased erythema (redness). It is another and more specific object of the present invention to provide such compositions that include the formulation of at least one α 1 -adrenoceptor agonist into a cosmetic, pharmaceutical or dermatological composition for decreasing and/or preventing skin redness and irritation as exhibited in rosacea or other conditions of the skin characterized by increased erythema and to administer said compositions to a mammal, notably a human, in order to treat or prevent the disease states indicated above. Additionally, it is an object of the present invention to provide such compositions that include the formulation of at least one α 1 -adrenoceptor agonist into a cosmetic, pharmaceutical or dermatological composition for decreasing and/or preventing skin redness and irritation as exhibited in rosacea or other conditions of the skin characterized by increased erythema in combination and admixed with other agents known to be effective in treating other manifestations of said skin conditions and to administer said compositions to a mammal, notably a human, in order to treat or prevent the manifestations of the disease states indicated above. The present invention is achieved by the provision of methods of treating rosacea or other conditions of the skin characterized by increased erythema, in a patient in need of such treatment, comprising the topical administration of a therapeutically effective amount of a composition comprising at least one α 1 -adrenoceptor agonist. α 1 -adrenoceptor agonists include, but are not limited to, oxymetazoline hydrochloride, tetrahydrozoline hydrochloride, naphazoline hydrochloride and phenylepherine hydrochloride. Preferably, the composition comprises at least one α 1 -adrenoceptor agonist formulated in a pharmaceutically/dermatologically acceptable medium, preferably a gel, cream, lotion or solution which is preferably administered by spreading the gel, cream, lotion or solution onto the affected area. Preferred embodiments may also include enhancers of cutaneous penetration or inhibitors or regulators of cutaneous penetration as required to increase therapeutic efficacy and/or decrease systemic absorption and any potential undesirable systemic effects of the active agent(s). detailed-description description="Detailed Description" end="lead"? | 20040122 | 20101012 | 20050728 | 97432.0 | 2 | CARTER, KENDRA D | METHOD AND THERAPEUTIC/COSMETIC TOPICAL COMPOSITIONS FOR THE TREATMENT OF ROSACEA AND SKIN ERYTHEMA USING A1-ADRENOCEPTOR AGONISTS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,763,957 | ACCEPTED | HOPPER CLOSURE ASSEMBLY AND METHOD OF USING SAME | A closure mechanism for a hopper bottom trailer which utilizes potential and kinetic energy of granular material in the hopper. The hopper closure assembly may have an angled member upon a gate that translates kinetic energy for moving granular material into longitudinal movement of the gate. The hopper closure assembly may have a raising structure which lifts the gate relative to the gate frame to create potential energy to assist in movement of the gate down the raising structure and in opening the discharge opening of the hopper. A method of using a hopper closure assembly which involves the steps opening the discharge opening by moving the gate longitudinally, also including the steps permitting the granular material to assist in opening the gate by striking the angled member, and additionally permitting the leading edge to move from the receiving member of the gate frame by descent from the raising structure. | 1. A hopper closure assembly for opening and closing a discharge opening in a hopper containing granular material, the hopper closure assembly comprising: a gate frame surrounding the discharge opening; a gate moveably mounted to the gate frame from a closed position in covering relation over the discharge opening to an open position uncovering at least a portion of the discharge opening for removal of the granular material through the discharge opening; the gate having a leading edge that moves across the discharge opening when the gate moves between the open and closed positions; a raising structure that engages and raises the leading edge of the gate when the gate moves to the closed position and that lowers the leading edge of the gate when the gate moves away from the closed position toward the open position. 2. The hopper closure assembly of claim 1 wherein the gate utilizes a weight force of the granular material acting on the gate to assist in movement down the raising structure. 3. The hopper closure assembly of claim 1 wherein the raising structure is a ramp. 4. The hopper closure assembly of claim 1 wherein the leading edge has an attached angled member and the gate frame has a receiving edge that accepts the angled member. 5. The hopper closure assembly of claim 1 further comprising a closure mechanism mounted on the gate frame to move the gate for opening and closing the discharge opening. 6. The hopper closure assembly of claim 5 wherein the closure mechanism has a rotatable member; an elongated arm having a secured end fixed for rotation with the rotatable member of the closure mechanism and a free end extending alongside the gate frame; a guideway attached to the gate having a toothed face and a smooth face, the guideway toothed face resistively engaging the rotatable member so rotation of the rotatable member moves the guideway longitudinally; a raceway mounted on the door frame; a roller wheel attached to the door forward the leading edge and rollingly engaging the raceway; roller wheels attached to the door frame and rollingly engaging the guideway smooth face. 7. The hopper closure assembly of claim 6 wherein the door frame has opposing side edges and opposing forward and rear edges; the raceway being mounted on the opposing side edges. 8. A hopper closure assembly for opening and closing a discharge opening in a hopper containing granular material that by gravity has a weight force extending toward the discharge opening, the hopper closure assembly comprising: a gate frame surrounding the discharge opening; a gate moveably mounted in approximately a horizontal direction to the gate frame from a closed position in covering relation over the discharge opening to an open position uncovering at least a portion of the discharge opening for removal of the granular material through the discharge opening; the gate having a leading edge that moves across the discharge opening when the gate moves between the open and closed positions; the leading edge having an angled member that angles away from the discharge opening and the granular material within the hopper, whereby the weight force of the granular material is in contact with the angled member in the closed position and engages the angled member during movement of the gate from the closed position to the open position and includes a horizontal component force that is in the direction of movement of the gate from the closed to the open position. 9. The hopper closure assembly of claim 8 further comprising a raising structure that engages and raises the leading edge of the gate when the gate moves to the closed position and that lowers the leading edge of the gate when the gate moves away from the closed position toward the open position. 10. The hopper closure assembly of claim 8 wherein the gate has a following edge opposite the leading edge, the leading edge approximately level with the following edge. 11. The hopper closure assembly of claim 8 wherein the angled member is L-shaped and the gate frame has a receiving edge that accepts the L-shaped member. 12. The hopper closure assembly of claim 10 further comprising a raising structure attached to the gate frame that lifts the leading edge of the gate relative the following edge. 13. The hopper closure assembly of claim 12 wherein the gate pivots upwardly from the following edge. 14. The hopper closure assembly of claim 12 wherein the leading edge of the gate is adapted to move downward from the raising structure to assist in opening the discharge opening. 15. A hopper closure assembly for opening and closing a discharge opening in a hopper containing granular material, comprising in combination: a gate frame engaging the discharge opening; a gate operably mounted in the gate frame for longitudinal and vertical movement; a leading edge on the gate adapted for vertical movement; a raceway upon the gate frame permitting longitudinal movement of the gate; and a raising structure within the raceway permitting the vertical movement of the leading edge. 16. The hopper closure assembly of claim 15 wherein the raising structure is a ramp. 17. The hopper closure assembly of claim 15 wherein the gate has a following edge opposite the leading edge, the following edge maintained approximately parallel the longitudinal axis when the leading edge is raised. 18. The hopper closure assembly of claim 15 wherein the leading edge of the gate is adapted to move downward from the raising structure to assist in opening the discharge opening. 19. A method of opening a hopper closure assembly having a hopper containing granular material and a discharge opening below the granular material whereby the granular material by gravity has a weight force directed toward the discharge opening, the method comprising: moving in approximately a horizontal direction a gate having a leading edge from a closed position wherein the gate covers the discharge opening to an open position wherein the gate opens the discharge opening to permit the granular material to move through the discharge opening; angling an angled portion of the leading edge of the gate away from the discharge opening whereby the weight force of the granular material acting on the angled portion while in the closed position will exert a horizontal component force on the gate in the direction of movement of the gate from the closed to the open position. 20. The method of claim 19 further comprising providing a raising structure upon the gate frame to elevate the leading edge of the gate, permitting the leading edge to move from the receiving edge by descent from the raising structure. 21. A method of opening a hopper closure assembly having a hopper containing granular material and a discharge opening below the granular material whereby the granular material by gravity has a weight force directed toward the discharge opening, the method comprising: moving a gate having a leading edge from a closed position wherein the gate covers the discharge opening to an open position wherein the gate opens the discharge opening to permit the granular material to move through the discharge opening; guiding the leading edge of the gate in a direction away from the discharge opening during movement of the gate from the closed to the open positions; providing a raising structure upon the gate frame to elevate the leading edge of the gate, permitting the leading edge to move from the receiving edge by descent from the raising structure. 22. The method of claim 21 further comprising the step angling an angled portion of the leading edge of the gate away from the discharge opening whereby the weight force of the granular material acting on the angled portion will exert a horizontal component force on the gate in the direction of movement of the gate from the closed to the open position. 23. A method of opening a hopper closure assembly, comprising: providing a hopper containing granular material and a discharge opening below the granular material whereby the granular material by gravity has a weight force directed toward the discharge opening; providing a longitudinal sliding gate which parallels a plane defined by the discharge opening; providing a downward angled leading edge upon the sliding gate, the leading edge exposed to the granular material when the gate is in a closed position wherein the gate covers the discharge opening; moving the gate from a closed position to an open position wherein the gate opens the discharge opening to permit the granular material to move through the discharge opening; interacting the granular material with the gate to assist in movement; guiding the leading edge of the gate in a direction away from the discharge opening during movement of the gate from the closed to the open positions. 24. The method of claim 23 further comprising providing a raising structure upon the gate frame to elevate the leading edge of the gate, permitting the leading edge to move from the receiving edge by descent from the raising structure. 25. The method of claim 23 further comprising angling an angled portion of the leading edge of the gate away from the discharge opening whereby the weight force of the granular material acting on the angled portion will exert a horizontal component force on the gate in the direction of movement of the gate from the closed to the open position. | BACKGROUND OF THE INVENTION The present invention relates to a closure mechanism for a hopper bottom trailer. Trailers used for handling grain or other bulk materials generally have a pair of spaced apart vertical sidewalls and a bottom wall having inclined front and rear portions. In the center of the bottom wall is usually mounted a hopper having a discharge opening at its lower end. In conventional trailer construction a longitudinal sliding gate which parallels a plane defined by the discharge opening is used to abut and close the discharge opening. One disadvantage of the conventional sliding gate is that it is difficult to move when fully loaded with grain or other bulk materials. To move the conventional sliding gate a handle is typically provided and an operator provides the energy to move the gate. However, there is a tremendous reserve of energy in the hopper bottom trailer in both potential energy stored by grain elevated a distance above the gate and kinetic energy from the grain or other bulk materials moving out of the trailer once the gate is opened. Prior attempts have been made to make conventional sliding gates easier to move; however, these do not utilize the potential and kinetic energy of the bulk material in the hopper to assist in moving a longitudinal sliding gate. Instead, the prior attempts have attempted to use a pendulum door system or a reduced friction system to assist in opening a hopper gate. Therefore, a primary objective of the present invention is the provision of a closure assembly for a hopper bottom trailer which may utilize potential energy and/or kinetic energy stored in a trailer. A further objective of the present invention is the provision of a closure assembly which maintains the gate and gate frame of the closure mechanism in sealing engagement when closed. A still further objective of the present invention is the provision of a closure assembly which is economical to manufacture, durable in use and efficient in operation. SUMMARY OF THE INVENTION The foregoing objectives may be achieved by using a hopper closure assembly positioned adjacent the discharge opening and a hopper containing granular material. The hopper closure assembly having a gate frame surrounding the discharge opening and a gate operably mounted in the gate frame for movement along a longitudinal axis to open or close the discharge opening. In one embodiment, the gate frame has a raising structure that lifts a leading edge of the gate higher than a following edge of the gate. In this position, the gate is provided with potential energy to assist in moving the door away from the door frame when it is filled with granular material. The foregoing objectives may also be achieved with a hopper closure assembly that utilizes an angled member upon the gate that translates kinetic energy from moving granular material into longitudinal movement of the gate relative the gate frame. The features of both a raising structure and an angled member may be combined into the same hopper closure assembly. The foregoing objectives may also be achieved by a method of using a hopper closure assembly which has the steps of closing the discharge opening by placing the angled member of the hopper closure assembly in sealing engagement with a receiving member of the gate frame, filling the hopper with granular material, opening the discharge opening by moving the gate longitudinally, and permitting the granular material to assist in opening the gate. The method also has the steps of the granular material striking the angled member of the gate. In addition, the method may have the step permitting the leading edge to move from the receiving member of the gate frame by descending down the raising structure. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a truck trailer utilizing a closure assembly of the present invention. FIG. 2 is a perspective view of the closure assembly with the gate in a partially open position and the hopper shown in phantom lines. FIG. 3 is a front view of the closure assembly without the receiving member shown with the gate in the closed position. FIG. 4 is a rear view of the closure assembly with the gate in the open position. FIG. 5 is a sectional view of the closure assembly taken along lines 5-5 in FIG. 2 showing the gate in a partially open position. FIG. 6 is a sectional view of the closure assembly showing the gate in a closed position. FIG. 7 is a side view of the slide gate illustrating the potential energy stored and utilized by the closure assembly. FIG. 8 is a side view of the slide gate utilizing the kinetic energy of granular material exiting from the hopper bottom. FIG. 9 is a side view of the slide gate illustrating an alternate embodiment of a raising member. DETAILED DESCRIPTION OF THE DRAWINGS As seen in FIG. 1, the numeral 10 refers generally to a hopper bottom trailer having a forward end wall 12, rearward end wall 14 and opposite side walls 16. The hopper bottom trailer is designed to haul granular material 18. The granular material 18 may be grain (i.e. corn, soybeans or other agricultural commodity), coal, fertilizer, meal, meat scraps, other non-liquid material, etc. Trailer 10 includes a kingpin structure 20 at its forward end which is adapted to be connected to the fifth wheel of a truck (not shown). Trailer 10 also includes a jack assembly 22 at its lower forward end which is adapted to support the forward end of the trailer when the trailer is disconnected from the truck. Bottom members 24 and 26 extend downwardly at a slope from the top edge of each end wall 12 and 14 toward the center of the trailer to the bottom edge of side walls 16. Bottom members 28 and 30 extend downwardly at a slope from the center of the trailer to the bottom edge of side walls 16. Bottom members 24, 26, 28 and 30 slope at an angle conducive to the flow of grain or other bulk materials down the slope to the hoppers 32. Hoppers 32 are provided on the trailer. Although a pair of hoppers 32 is illustrated, any number of hoppers may be utilized. Further, although it is described that the hoppers 32 of this invention are utilized on a trailer, it should be understood that the hoppers would also function satisfactorily on a truck body. While the elements 32 are shown as being a hopper, they are generally open top containers and could be an open top tank, bin or hopper for stationary use or as parts of ocean shipping containers or other mobile conveyance, for storing, transporting or processing bulk material and could extend upwardly a greater distance than shown in the drawings and comprise a larger portion of the entire trailer than is presently shown. Hopper 32 includes a forward wall 34, rearward wall 36, and opposite side walls 38, 40. As illustrated in FIG. 2, the forward and rearward walls 34, 36 and side walls 38, 40 extend downwardly and inwardly to form discharge opening 42. A hopper closure assembly 44 engages opening 42 and is moveable between a closed position and an open position. The hopper closure assembly 44 has a gate frame 46 and a gate 48 mounted to the gate frame 46. A closure mechanism 50 moves the gate 48 between open and closed positions. The gate frame has a first end wall 52, a second end wall 54 and first and second opposite sidewalls 56, 58. These walls 52, 54, 56, 58 define an opening to surround the discharge opening 42 of the hopper 32. A portion of these walls is out turned to match the angle of the hopper 32 walls. The gate frame 46 is attached to the hopper 32 by bolts, rivets, welding, or other fastening means. As seen in FIGS. 2, 5 and 6 the first end wall 52 has an angle which conforms to the hopper bottom front side 34. The first end wall 52 has a portion that extends between the first and second sidewalls 56, 58 while still permitting the gate 48 to move underneath it. The first end wall 52 therefore does not have the same height as sidewalls 56, 58 and permits the gate 48 to roll underneath it. The second end wall 54 has approximately the same height as first sidewall 56 and second sidewall 58. The second end wall 54 of the gate frame 46 has a receiving edge 60. As seen in FIGS. 5 and 6 the receiving member 60 has a Z-shaped cross section. This Z-shape is designed to receive an L-shaped member 63. As shown most clearly in FIGS. 3 and 4, the first and second sidewalls 56, 58 have a lower edge that is turned inwards to form a raceway. As seen in FIGS. 2, 3 and 9, a raising structure 66 is placed within the raceway 64 in both sidewall 56 and sidewall 58. The raising structure 66 may be a ramp as illustrated in FIGS. 2, 3, 5-8, hinged swivel as illustrated in FIG. 9, or other raising structure that lifts the leading edge 62 higher than the following edge 74. The hinged swivel raising structure 66 as in FIG. 9 utilizes a swivel 96 attached by a hinge to the gate 48 and the wheel 72A. When the wheel 72A moves along the raceway 64 it contacts a block 100 which prevents longitudinal movement of the wheel 72A but permits the swivel 96 to move about the wheel and elevate the gate 48. Additionally wheels 68, 70 are mounted to the sidewalls 56, 58 to accept the gate 48 traveling along longitudinal axis X-X as seen in FIGS. 2, 5 and 6. Additionally, the gate 48 has a wheel 72 mounted to it. When the gate 48 is traveling along longitudinal axis, wheels 68, 70 and 72 support the gate 48. As the wheel 72 travels up the raising structure as seen in FIG. 6, the gate is along gate axis G-G and supported by rear wheel 70 and wheel 72. As previously mentioned, the gate 48 has an L-shaped member 63. The gate 48 also has a following edge 74 and first and second side edges 76, 78. The leading edge 62 is never below the following edge 74. When the wheel 72 is upon the raising structure 66 the leading edge 62 is above the following edge 74 and the gate is parallel axis G-G. When the gate wheel 72 is off the raising structure 66 and directly upon the raceway 64 the leading edge 62 is level with following edge 74 for the gate to be parallel longitudinal axis X-X. The invention uses a closure generally referred to by numeral 50 to move the gate between the open position and the closed position. The closure 50 has first and second pinions 80, 82 connected by a cross bar 84. The cross bar extends outside the sidewall 56 to end in a shaft 86 that is approximately 1 inch long. Attached to the shaft 86 may be an elongated arm (not shown) . The elongated arm is typically secured for rotation to the shaft 86 by a U-joint (not shown) so that rotation of the arm rotates the shaft 86 and in turn rotates first and second pinions 80, 82. The shaft may be rotated manually, hydraulically, pneumatically, or electrically. As seen in FIGS. 3, 4, 5 and 6 Rotation of pinions 80, 82 turn within first and second guideways 90, 92. The axis of rotation for the first and second pinion 80, 82 are in alignment with the second rear wheels 70. The gate 48 is moved between the rear wheels 70 and the first and second pinion 80, 82 by the pinions 80, 82 fitting within the guideways 90, 92. The guideways have a tooth face that resistively engage the pinion so that rotation of the pinion moves the guideway along the gate axis G-G when the front wheel is upon the raising structure 66 and along the longitudinal axis X-X once the gate wheel 72 comes off the raising structure 66. The first and second guideways extend the length of the gate 48 beginning at the first and second side edges 76, 78 and ending at the leading edge 62 when the L-shaped member 63 begins a downward angle. As seen in FIG. 7, the leading edge 62 is an area with greater potential energy then the rest of the closure assembly 44. Potential energy is the energy waiting to be converted into power. The formula for calculating the potential energy (PE) for a height increase is PE=force*distance. In this case, the force is equal to the weight of stored grain or granular material above the closure assembly 44 times the acceleration of gravity (G), and the distance is equal to the height change so the formula for this invention can be written: potential energy=mass*gravity*change in height. When dealing with a loaded hopper bottom trailer the mass in the above equation is many thousand pounds and therefore even slight changes in height will produce a dramatic potential energy. As seen in FIG. 7, the raising structure 66 has a change in height, H1. The height difference H2 is achieved by riding the wheel 72 up raising structure 66. Additionally, the invention uses kinetic energy to assist in opening the gate 48 within the gate frame 46. Kinetic energy takes into consideration the velocity of the granular material flowing onto the leading edge. Kinetic energy is calculated by the equation ½ mass*velocity2. As seen in FIG. 8, the moving granular material puts force F on the gate 48 by striking the angled member 63 which has a horizontal component or vector V approximately equal to 0.707 F. The vector V may be altered by changing the angle of the angled member 63. As seen in the figures, the angled member 63 is pitched approximately 45 degrees from the gate 48. Without the angled member 63 the force F would not act upon the gate 48 and would not assist in opening the gate 48. With the angled member, the kinetic energy or moving energy of the grain is transferred to the gate 48 as a force for movement along the longitudinal axis X-X. While the angled member 63 is shown as a flat plate, it is to be understood that the angled member 63 may take other configurations including a rounded edge and other configurations which translate the force of downward moving granular material into a force for moving the gate longitudinally. Seals 94 are provided to prevent any granular material from escaping from the inner connections between the hopper bottom sides 34, 38, 40 and the gate 48. The seal between the forward wall 34 and the gate 48 flexes as the gate moves between the open and closed positions. In use, the operator uses the closure assembly 44 upon the hopper bottom trailer 10 by closing the closure assembly 44 while the hopper bottom 32 of the hopper bottom trailer 10 is empty. When the hopper bottom 32 is empty the operator easily rotates arm to rotate the pinions 80, 82 to place the gate 48 having an L-shaped angled member 63 against the gate frame 46 having a receiving member 60. When the hopper 32 is empty the operator can easily close the gate because the gate is turning upon wheels 68, 70 and 72. Just prior to closing the gate 48, that had been moving along a longitudinal axis, the leading edge 62 is elevated to form the gate axis G-G. When on the raising structure 66, the gate 48 is being moved upon a second rear wheel 70 and the gate wheel 72. The gate wheel 72 moves up a raising structure 66 positioned in a raceway 64 of the gate frame 46 to create this vertical movement. This vertical movement places the angled member 63 in sealing engagement with the receiving edge 60 to close the discharge opening 42 of the hopper 32. The operator then moves the arm to a locked position where it will not accidentally disengage the gate 48 away from the gate frame 46. The operator is then free to fill the hopper bottom trailer 10 with grain or other granular material. As grain 18 loads into the hopper 32 the grain 18 acquires a potential energy because the leading edge 62 is in a position higher vertically than the leading edge during longitudinal movement. The operator empties the trailer 10 by opening the gate 48 on the hopper closure assembly 44. Initially, the operator moves the arm to a position from a locked position to an unlocked position which permits the potential energy to be translated into a weight force with a horizontal and vertical component. The gate begins moving downward and the wheel 72 rolling down raising structure 66. The gate 48 then rolls longitudinally assisted by the weight force of the granular material 18 acting on the angled member 63, the weight force exert a horizontal component force of the grain 18 moving against the angled member 63 and pushing the door 48 longitudinal. At the same time the operator moves the pinions 80, 82 by turning the arm to rotate the cross bar 84. The operator will open the gate to a desired opening to permit granular material flowing from the discharge opening 42, onto the ground, into an in ground auger, pit, conveyor, etc. The emptying will continue until the hopper bottom trailer is completely empty or until the desired amount of granular material 18 has been removed. In the drawings and specification there has been set forth a preferred embodiment of the invention, and although specific terms are employed, these are used in a generic and descriptive sense only and not for purposes of limitation. Changes in the form and the proportion of parts as well as in the substitution of equivalents are contemplated as circumstances may suggest or render expedient without departing from the spirit or scope of the invention as further defined in the following claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>The present invention relates to a closure mechanism for a hopper bottom trailer. Trailers used for handling grain or other bulk materials generally have a pair of spaced apart vertical sidewalls and a bottom wall having inclined front and rear portions. In the center of the bottom wall is usually mounted a hopper having a discharge opening at its lower end. In conventional trailer construction a longitudinal sliding gate which parallels a plane defined by the discharge opening is used to abut and close the discharge opening. One disadvantage of the conventional sliding gate is that it is difficult to move when fully loaded with grain or other bulk materials. To move the conventional sliding gate a handle is typically provided and an operator provides the energy to move the gate. However, there is a tremendous reserve of energy in the hopper bottom trailer in both potential energy stored by grain elevated a distance above the gate and kinetic energy from the grain or other bulk materials moving out of the trailer once the gate is opened. Prior attempts have been made to make conventional sliding gates easier to move; however, these do not utilize the potential and kinetic energy of the bulk material in the hopper to assist in moving a longitudinal sliding gate. Instead, the prior attempts have attempted to use a pendulum door system or a reduced friction system to assist in opening a hopper gate. Therefore, a primary objective of the present invention is the provision of a closure assembly for a hopper bottom trailer which may utilize potential energy and/or kinetic energy stored in a trailer. A further objective of the present invention is the provision of a closure assembly which maintains the gate and gate frame of the closure mechanism in sealing engagement when closed. A still further objective of the present invention is the provision of a closure assembly which is economical to manufacture, durable in use and efficient in operation. | <SOH> SUMMARY OF THE INVENTION <EOH>The foregoing objectives may be achieved by using a hopper closure assembly positioned adjacent the discharge opening and a hopper containing granular material. The hopper closure assembly having a gate frame surrounding the discharge opening and a gate operably mounted in the gate frame for movement along a longitudinal axis to open or close the discharge opening. In one embodiment, the gate frame has a raising structure that lifts a leading edge of the gate higher than a following edge of the gate. In this position, the gate is provided with potential energy to assist in moving the door away from the door frame when it is filled with granular material. The foregoing objectives may also be achieved with a hopper closure assembly that utilizes an angled member upon the gate that translates kinetic energy from moving granular material into longitudinal movement of the gate relative the gate frame. The features of both a raising structure and an angled member may be combined into the same hopper closure assembly. The foregoing objectives may also be achieved by a method of using a hopper closure assembly which has the steps of closing the discharge opening by placing the angled member of the hopper closure assembly in sealing engagement with a receiving member of the gate frame, filling the hopper with granular material, opening the discharge opening by moving the gate longitudinally, and permitting the granular material to assist in opening the gate. The method also has the steps of the granular material striking the angled member of the gate. In addition, the method may have the step permitting the leading edge to move from the receiving member of the gate frame by descending down the raising structure. | 20040123 | 20050823 | 20050728 | 85008.0 | 0 | GUTMAN, HILARY L | HOPPER CLOSURE ASSEMBLY AND METHOD OF USING SAME | SMALL | 0 | ACCEPTED | 2,004 |
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10,764,070 | ACCEPTED | Structured fluid compositions for electrophoretically frustrated total internal reflection displays | A structured fluid composition comprising: (a) a low refractive index liquid; (b) particles including light absorbing charged particles such as pigments, non-light absorbing uncharged particles such as teflon, silica, alumina and combinations thereof; and (c) at least one additive selected from the group consisting of a dispersant, a charging agent, a surfactant, a flocculating agent, a polymer, and combination thereof; for use in a TIR electronic display. The inventive composition improves the long-term stability, response time and visible appearance of image displays which electrophoretically frustrate total internal reflection (TIR). | 1. A structured fluid composition comprising: (a) a low refractive index liquid; (b) at least one particle selected from the group consisting of a light absorbing particles such as pigments, non light absorbing particles such as teflon, silica, alumina and mixtures there of, and combinations thereof; and (c) at least one additive selected from the group consisting of (i) a dispersant, (ii) a charging agent, (iii) a surfactant, (iv) a flocculating agent, (v) a polymer, and (vi) combination thereof; resulting in a stable suspension that is not agglomerated or clustered, having ionically charged light absorbing particles, and forming an interactive structure which inhibits motion, and for use in a TIR electronic display. 2. An electronically addressable display, comprising: (a) a transparent upper front sheet; (b) a lower sheet that is essentially parallel to and spaced from the upper front sheet; (c) a structured electrophoretic suspension substantially filling the space between the sheets which structure is controlled by the composition of the suspension, wherein the composition comprises a low refractive index liquid; a light absorbing particles such as pigments; particles which are not light absorbing such as teflon, silica, alumina and combinations thereof; and at least one additive selected from the group consisting of a dispersant, a charging agent, a surfactant, a flocculating agent, a polymer, and combination thereof; and (d) a means for applying a voltage across the suspension for controllably compressing the colloidal suspension away from the inward surface of the front sheet to either form a thin particle free liquid layer to allow total internal reflection or a layer with a higher concentration of particles to frustrate total internal reflection at the inward surface of light rays passing through the front sheet. 3. The composition of claim 1 wherein the liquid electrophoretic medium is comprised of substantially fluorinated oils. 4. The composition of claim 3 wherein the fluorinated oil is perfluorinated. 5. The composition of claim 1 wherein the particles occupy from about 1 to about 75% by weight of the electrophoretic suspension. 6. The composition of claim 1 wherein the particles comprise a blue pigment, red pigment, brown pigment, black pigment and combinations thereof. 7. The composition of claim 6 where the blue pigment is selected from a group consisting of chromophthal blue, metal containing phthalo blue, metal free phthalo blue indigo blue and combinations thereof. 8. The composition of claim 6 where the red pigment is selected from a group consisting of monastral red and combinations thereof. 9. The composition of claim 6 where the black pigment is selected from a group consisting of carbon black, modified carbon black, iron oxide, aniline black and combinations thereof. 10. The composition of claim 1 comprising a mixture of two or more pigment particles to enhance the optical properties, wherein the frustration of total internal reflection is improved by the collective absorption of different wavelengths of light. 11. The composition of claim 1 wherein the composition results in a colloidal structure with a non-Newtonian rheology. 12. The composition of claim 1 wherein the composition results in a colloidal structure which has a yield stress. 13. The composition of claim 1 wherein the particle has a surface treatment selected from the group consisting of reaction with an oxidizing or reducing chemical, reaction with a chemical that covalently bonds to the surface, grafting onto the surface with a plasma containing small molecules such as oxygen or monomers with various functional groups or mixtures thereof resulting in improved response time and as herein the dispersant forms a tightly packed monolayer adsorbed on the particle surface resulting in less particle agglomeration. 14. The composition of claim 1 (a) where-in the particle has a sufficient number of functional groups of either acid or base, to allow a dispersant to form a tightly packed mono-layer, and (b) wherein the dispersant has the complementary acid or basic functional group to interact with the particle surface and a molecular structure resulting in a strong interaction between the particle surface and the dispersant to inhibit agglomeration. 15. The composition of claim 1 wherein the suspended particles have at least two distinct particle size distributions one in the range of about 200 nm to about 500 nm and the other in the range of about 10 nm to about 100 nm. 16. The composition of claim 1 wherein the particles are coupled via reaction with a coupling agent and wherein the coupling agent is bi-functional. 17. The composition of claim 1 wherein the dispersant has only either an acidic functional group or a basic functional group. 18. The composition of claim 1 wherein the ratio of dispersant to pigment ranges from about 0.1 to about 3. 19. The composition in claim 1 where the concentration of pigment particles is adjusted to maintain small particle separation distance in a homogeneous dispersion so the distance that particles must move to produce a color change in TIR is small, and this results in fast response time in producing an image. 20. The composition of claim 1 where the pigment concentration is high enough to enable rapid color change in an electric field. 21. The composition in claim 1 with concentration of components adjusted to cause a yield stress to impede motion under low shear forces (such as gravity), but with a small enough yield stress to enable rapid motion of particles in a low electric field. 22. A colloidal suspension in claim 1 where the colloidal structure is due to weak flocculation. 23. The composition in claim 1 where the charging agent, dispersant or surfactant forms inverse micelles which increase the particle charge thereby improving the structure and response time of the mixture. | TECHNICAL FIELD The inventive composition creates a structured fluid which improves the long-term stability, response time and visible appearance of image displays which electrophoretically frustrate total internal reflection (TIR). BACKGROUND In electrophoresis an ionically-charged particle moves through a medium due to the influence of an applied electric field. The concept of electrophoresis can be combined with the principles of ‘Total Internal Reflectance’ (TIR) to create addressable displays. A suspension of particles can be used to controllably frustrate TIR and switch the state of pixels in such displays in a cotrolled manner. For example, an electromagnetic field can be applied to move charged particles in the suspension through an electrophoretic medium toward or away from an evanescent wave region to frustrate TIR at selected pixel portions of the region. In order for the electronic display to be useful the display should have quick response times. Further it is desirable that there is good contrast between the dispersed particles and the white background and that the electrophoretically active suspension remains stable. It is known that repeated switching of a display which utilizes electrophoretically-mobile particles can result in a non-uniform distribution or movement of the particles, gradually causing the formation of particle clusters which deteriorates the quality of images produced by the display over time. An example is found in Dalisa, A., “Electrophoretic Display Technology,” IEEE Transactions on Electron Devices, Vol. 24, 827-834, 1977; and Mürau et al, “The understanding and elimination of some suspension instabilities in an electrophoretic display,” J. Appl. Phys., Vol. 49, No. 9, September 1978, pp. 4820-4829. It has been shown that such undesirable clustering can be reduced by encapsulating groups of suspended particles in separate micro-fluidic regions. See for example Nakamura et al, “Development of Electrophoretic Display Using Microencapsulated Suspension,” Society for Information Display Symposium Proceedings, 1014-1017, 1998 and Drzaic et al, “A Printed and Rollable Bistable Electronic Display,” Society for Information Display Symposium Proceedings, 1131-1134, 1998. In summary it is desirable for an electronic display to have long term stability, quick response time and high contrast between the background and image being displayed. The invention has discovered that certain compositions have a combination of physical properties which overcome these obstacles in particular on electrophoresis. SUMMARY OF INVENTION The inventive composition creates a structured fluid which improves the response time, visible image and long-term image stability of an electrophoretically-mobile particle display. The composition comprises 1) a low refractive index liquid, which is the electrophoretic medium 2) particles selected from the group consisting of light absorbing particles such as pigments which are charged, non-light absorbing uncharged particles which increase the viscosity such as, teflon, silica, alumina and the like and combinations thereof, 3) additives which include a) dispersants, b) charging agents, c) surfactants (also interchangeable with the term surface action agents), d) flocculating agents, e) polymers and f) and combinations thereof. The composition is used to improve response time to form a display image after application of an electric field. The composition forms a structured suspension of particles in which the particles are stable from agglomeration. The particles interact through colloidal forces controlled by the composition which inhibits particle motion under low stress caused by gravity or by the osmotic flow of ions in an electric field induced by reversing the electric field as the display's pixels are switched between reflective and non-reflective states, without encapsulating the ink in isolated compartments. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a fragmented, cross-sectional view, on a greatly enlarged scale, of a portion of a prior art electrophoretically frustrated TIR image display, depicting undesirable non-uniform particle distribution. FIG. 2A is a fragmented, cross-sectional view, on a greatly enlarged scale, of a portion of a prior art electrophoretically frustrated TIR image display, before application of an electric field. FIG. 2B depicts the FIG. 2A display after selective application of an electric field. FIG. 3B is a fragmented, cross-sectional view, on a greatly enlarged scale, of a portion of one pixel of an electrophoretically frustrated TIR image display in accordance with the invention, before application of an electric field. FIG. 3A depicts the FIG. 3B display after selective application of an electric field. DETAILED DESCRIPTION FIG. 1 shows dilute mixtures in unrestricted motion—historical prior art herein referred to as Case 1. FIG. 1 depicts a portion of a TIR image display which uses electrophoretic dispersions to create an image. The upper polymeric sheet 42 contains an array of reflective microprisms 44. The sheet can be constructed with prismatic geometry or my contain hemispherical high refractive index transparent hemi-beads, as described in U.S. patent application Ser. No. 10/086,349 filed 4 Mar. 2002 which is incorporated herein by reference. A thin, continuous, transparent electrode such as an indium tin oxide (ITO) coating 46 is applied to the inward surfaces of prisms 44. A segmented electrode 50 is applied to the inward surface of the bottom sheet, 48 to apply separate voltages (corresponding to individual pixels) between each adjacent pair of prisms 44. An electrophoresis medium—continuous liquid 58, for example, a low refractive index, low viscosity, electrically insulating liquid such as Fluorinert™ perfluorinated hydrocarbon liquid available from 3M, St. Paul, Minn. substantially fills the space between the sheets forming a TIR interface between the two sheets 42 & 48. This mixture also contains additives that interact with the particle surface to make it become ionically charged. This primary composition is a homogeneous dispersion of particles—suspension which will fill the liquid 58 uniformly, and the concentration of particles 52 is relatively low, in the order of 1% by weight. The particles 52 in this composition Case 1 are well dispersed; they randomly move by Brownian motion, and they will segregate from the liquid 58 under the influence of gravity. The particle separation is many times (in the order of ten times) greater than the particle size, so there are very few particles near the surfaces of the reflective micro-prisms 44. A voltage source (not shown) is electrically connected between the electrodes on the prism surface 46 and the bottom segmented electrodes 48 to controllably apply a voltage across selected pixel regions of liquid medium 58. Application of a voltage across a selected pixel region electrophoretically moves particles 52 (pigments) suspended within the selected region to form a layer that begins within about 0.25 micron of the evanescent wave zone adjacent the inward surfaces of the selected region's prisms and extends about 5 microns into the region. When electrophoretically moved as described, particles in the suspension 54, which have a higher refractive index than the surrounding liquid 58 and are much smaller than a wavelength of light and therefore substantially non-light-scattering, cause the layer to have an effective refractive index that is substantially higher than that of the surrounding liquid 58. This absorptive particle layer causes absorption of the light as it passes through the upper sheet. This gives the selected pixel region a dark appearance to an observer who looks at outer surface of the microprism upper sheet 42. This process is slow (compared to Case 3-type compositions) because a number of particles 52 must move a relatively long distance to produce this optical effect. Application of an opposite polarity voltage across the selected pixel region electrophoretically moves the suspended particles 54 toward that lower segmented electrode 50. As a result the particles 52 are out of the evanescent wave zone and the light which passes through the microprisms 44 undergoes TIR so the region has a white appearance to an observer who looks at the sheet's outer surface. Additional details of the construction of these displays and optical characteristics of electrophoretically-frustrated TIR image displays can be found in U.S. Pat. Nos. 6,064,784; 6,215,920; 6,304,365; 6,384,979; 6,437,921; and 6,452,734 all of which are incorporated herein by reference; and, in the aforementioned U.S. patent application Ser. No. 10/086,349. The bottom electrode can be segmented to provide electrode segments 50, as shown in FIG. 1. A controller (not shown) can then be used to selectively apply a voltage to each pair of electrodes in the segmented electrode array. Each electrode segment 50 (or group of adjacent electrode segments) corresponds to an individually controllable pixel. Dispersed particles in the suspension 54 will tend to agglomerate or stick together as they move near one another because of van der Waals attractive forces. The dispersants are added to the mixture to inhibit agglomeration, and they do this by forming a barrier from electrostatic or osmotic pressure forces. However, the dispersion 54 is inherently unstable. These lyophobic colloidal dispersions require a great deal of mixing energy when being made. They are thermodynamically unstable, but the dispersant barrier helps to inhibit the ultimate breakdown that is agglomeration, size growth and separation of the two phases. When these dispersions 54 are put in an electric field which moves the particles 52 they will collide with tremendous force and this will tend to enhance agglomeration. These dispersants as commonly used to stabilize suspensions, that is provide a barrier to inhibit agglomeration when particles collide with thermal energy, but they will not provide a large enough barrier to prevent agglomeration with the collision force induced by an electric field. Also, as the field is reversed consecutively, electric field gradients will cause the charged particles and ions to migrate between adjacent cells. As a result, particles 52 in these Case 1 compositions will tend to accumulate or cluster 56 in regions, and they will not readily diffuse back to fill space uniformly. The particles in these Case 1 compositions will also tend to segregate from gravity driven motion due to differences in density between the particles and liquid. This will also tend to result in regions with high higher and lower particle concentration. The motion of particles 52 in an electric field gradient and the clustering 56 will also tend to enhance agglomeration. The particles 52 in these Case 1 compositions will rotate in the field gradient, and as they are packed into clusters particles 56 will tend to arrange so that the part of the particle with least repulsive forces are closest. The particle surfactant coating may well be non-uniform and the charge distribution may be non-uniform—hence, the particle motion and clustering will tend to enhance contact between the parts of the particle that are most likely to have strong attraction; so they will agglomerate. These phenomena are illustrated in FIG. 1. Electrophoretically-frustrated display can exhibit undesirable clustering of particles 56 in the suspension 54 over time. More particularly, particles 52 tend to form loose agglomerates, surrounded by regions of the electrophoretic medium 58 containing relatively few suspended particles 52. Such clustering often results in long-term deterioration of the display's image quality and overall performance. FIG. 2A and 2B show dilute mixtures in confined compartments—prior art to minimize cluster formation herein referred to as Case 2. FIGS. 2A and 2B depict a prior art technique for reducing undesirable particle clustering with an ink composition. This composition is similar to that in Case 1 composition in an electrophoretically-frustrated display having a transparent upper ‘microprism’ sheet 72 and a lower substrate sheet 78. The upper sheet 72 contains an array of parallel reflective microstructred prisms 74. The tip of the microprisms 74 are connected to the lower sheet 78 as illustrated. This forms an encapsulated channel 88 between opposed facets of each adjacent pair of prisms. The encapsulated channels 88 will prevent particle migration between adjacent cells, and it can also inhibit particle sedimentation, and this will reduce formation of particle clusters. Each channel is filled with an electrophoresis liquid medium 80, forming a TIR interface between the upper microprism sheet 72 and the continuous liquid medium 80. This continuous liquid medium 80 contains a finely dispersed suspension 86 of pigment particles 84. A thin transparent electrode such as ITO 76 is applied to the inward surface of the upper microprism sheet 72. A segmented electrode 82 is applied to the inward surface of the lower sheet 78, to create separate pixel regions corresponding to each channel (or a group of adjacent channels 88). A voltage source (not shown) is electrically connected between the electrodes on the prism surface upper ITO coated electrode 76 and the bottom sheet segmented electrodes 82 to controllably apply a voltage across selected pixel regions of liquid medium 80. Application of a voltage across a selected pixel region electrophoretically moves pigment particles 84 suspended within the selected region to form a layer that begins within about 0.25 micron of the evanescent wave zone adjacent the inward surfaces of the selected region's prisms and extends about 5 microns into the region. When electrophoretically moved as described, particles in the suspension 86, which have a higher refractive index than the surrounding fluid 80 and are much smaller than a wavelength of light and therefore substantially non-light-scattering, cause the layer to have an effective refractive index that is substantially higher than that of the surrounding liquid 80. This absorptive particle layer 90 causes absorption of the light ray 70 as it passes through the upper sheet 72. This gives the selected pixel region a dark appearance to an observer who looks at outer surface of the upper ‘microprism’ sheet 70. This process is slow (compared to Case 3—type compositions) because a number of pigment particles 84 must move a relatively long distance to produce this optical effect. Application of an opposite polarity voltage across the selected pixel region electrophoretically moves the suspension of pigment particles 86 toward that lower segmented electrode 82. As a result the pigment particles 84 are out of the evanescent wave zone and the light which passes through the microprisms 74 undergoes TIR 68 so the region has a white appearance to an observer who looks at the sheets outer surface. In Case 2, although encapsulation of the ink into compartments keeps the suspension of particles 86 within separate channels 88 and reduces undesirable clustering, it may in some cases be impractical to fabricate, fill or maintain channels 88. In Case 2 the encapsulation may not completely eliminate particle clustering and agglomeration in the ink because they can segregate within a cell, and the strong electric field will still increase the force of particle collisions. The inventive composition herein, Case 3, provides a suspension 110 with structure to minimize cluster formation, and improve contrast and speed. The composition of the invention creates a stable dispersion with a colloidal structure where the light absorbing particles 100 are charged. The composition comprises 1) a low refractive index liquid 104 which is the electrophoretic medium; 2) particles 100 including light absorbing particles such as pigments which are charged and low light absorbing uncharged particles which increase the viscosity and provide part of the interactive or structured network, such as, teflon, silica, alumina and the like; and 3) additives which include a) dispersants, b) charging agents, c) surfactants, d) flocculating agents, e) polymers and f) and combination thereof. The composition also provides for good contrast of a dark image in a white background, and a rapid response time to form the image after application of the electric field. The composition may be a mixture of particles which form a very dark color, preferably black. It is preferable to have a dark image against a light such as white background. The concentration and nature of components in the composition are adjusted to form a structured fluid where the particles interact with each other and the other components so they will not readily flow under a low stress, but will move rapidly in an electric field to form an image. The composition contains a low refractive index liquid which include fluorinated liquids, Fluorinert perfluorinated hydrocarbon liquid manufactured by 3M, St. Paul, Minn., Krytox Oil, a perfluoropolyether manufactured by DuPont performance Lubricants, Wilmington, Del. and the like. The low refractive index liquid may be used in combinations thereof. The low refractive index has a low dielectric constant in the range of about 1 to about 20, preferably about 1 to about 10 and more preferably about 1 to about 5. The low dielectric constant reduces the overall conductivity of the composition. The low reactive index liquid includes polar, non-polar and mixtures thereof, preferably the low reactive index liquid is non-polar. The liquid is in the composition in the range of about 10 wt. % to about 95 wt. %, preferably about 30 wt. % to about 60 wt. % of the composition. The low refractive index liquid has a molecular weight in the range of about 100 to about 5,000, preferably about 200 to about 5000 and more preferably about 500 to about 1000 and a viscosity in the range of about 1 centipoise to about 100 centipoise preferably about 1 centipoise to about 10 centipoise. The refractive index difference between the polymer transparent front sheet of the display and liquid is as large as possible, at least about 0.15 and preferably at least 0.30. The volatility of the liquid should be as low as possible while maintaining a low viscosity. The chemical structures of exemplary liquids are shown below. Paritally fluorinated fluids can also be used. Structure of Krytox Oil is as Follows: Krytox Oil TFL 8896, Polyhexafluoropropylene oxide 1,1,1,2,2,3,3-Heptafluoro-3-pentafluoroethyloxy-propane for n=1 The Structure of Fluorinert Oil is as Follows: Fluorinert FC-75, perfluorinated fluid 1,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-Octadecafluoro-octane It is preferable that the liquid has as a low refractive index as possible (per fluorinated liquids have the lowest refractive index). The composition contains additives which are soluble in the liquid and which stabilize the suspended particles (prevent agglomeration) and cause the particles to become charged so they are electrophoretically active. The composition contains particles which include light absorbing particles, very low light absorbing particles and/or non-light absorbing particles which increase the viscosity of the overall composition and provide part of structural network, and mixtures thereof. In one embodiment of the invention the particles in the composition are preferably light absorbing particles. In another embodiment of the invention the particles in the composition are preferably light absorbing particles and non-light absorbing particles. The light absorbing particles include pigments, metals, mixtures thereof and the like; they are finely dispersed in the liquid electrophoretic medium, and they are charged. The non-light absorbing particles are finely dispersed in the liquid, and they include organic polymers such as teflon, polystyrene, nylon, polycarbonate and the like and inorganic compounds such as silica, alumina, calcium carbonate, clays (kaolin, bentonite, montmorillonite, etc.) and the like and combinations thereof, and these particles are added to help create a structured colloidal dispersion. However, they are not charged in the composition because they do not contribute to the optical effects. These particles may be spheroidal, polyhedral or have a high aspect ratio like needles or rods which can enhance the structure of the mixture. The uncharged particles are in the composition in the range of about 0 wt. % to about 60 wt. % and preferably about 2 wt. % to about 20 wt. % of the composition. Pigments are colored particles which may be organic or inorganic in nature. Pigments can be broadly classified into colored and white pigments. White pigments are inorganic while colored pigments can be organic or inorganic. The pigments include quinacridones which are red or copper colored, pthalocyanines which are blue, or carbon black, iron oxide or aniline black which are black and combinations thereof. Strongly colored pigments are preferable since they offer high contrast with the background. A composition containing equal weight mixtures of a quinacridone and pthalocyanine pigment produce a very dark color which is especially suitable for many displays. The pigment particles can be a mixture of more than one and are in the ratio in the range of 50 wt. % to about 50 wt. %, in one embodiment about 30 wt. % to about 70 wt. %, and in another embodiment about 20 wt. % to about 80 wt. %. For the purpose of using pigments in outdoor display applications it is desirable that they possess general characteristics as follows. Property Desired Color Dark Light Fastness High Ease of Dispesion High Presence of metal ion Acceptable Particle size <300 microns, and preferably <450 microns. The color and light fastness depends on the structure of the pigment, and the pigments with the above properties are desired. The surface chemistry of the pigment controls its dispersion, and particle size. The particle may contain amine functionality, nitrogen containing molecules that impart bascity, acidic functional groups and the like. The particle may contain combinations of functionality. Exemplary amine functionality are shown in the structures below, the quinacridone and pthalocyanine pigments. The quinacridone pigment, NRT-796D-Monastral Red-B is represented by the structure as follows The pthalocyanine pigment, Cromophtal Blue A3R is represented by the structure as follows: Examples of pigment particles with exemplary nitrogen containing segments in the structure imparting a degree of basicity to the pigment surface include aniline black and the like. Carbon black has acidic groups on its surface, including carboxylic acid and phenolic groups, and other commercial pigments have acidic functional groups. The surface chemical functional groups are the sites for interaction with the other components in the composition. Pigments are further modified by surface treatments. These surface treatments in turn impart additional functional groups for interactions with other components in the composition. The particle concentration in the composition is adjusted to obtain a particle separation which promotes particle/particle interactions (long range), and generally this results in an ordered arrangement of particles, that is a colloidal structured fluid. The particles are in the composition in the range of about 1 wt. % to about 75wt. %, preferably about 10 wt. % to about 60 wt. % of the composition. The interactions include coulombic interactions, steric interactions, osmotic pressure interactions and the like induced from absorbed or attached surfactants, depletion force interactions from polymers dissolved in the liquid, and attractive forces between particles in a weakly flocculated state. These interactions are facilitated by other components in the composition and these components also assist in preventing particle agglomeration. The particle spacing (needed for desired particle-particle interactions) depends upon the concentration of other components which interact collectively to produce the interactive forces. The desired spacing depends upon the balance of forces which restrict motion and inhibit segregation of particles with the ability to move quickly in response to an electric field resulting in fast response time. The composition may contain two or more sets of particles with different particle size distributions to improve the structure by enabling a more efficient packing arrangement. This enables a higher loading of particles and smaller separation distances between particles, and then stronger interactions between particles. The viscosity is higher, and the structuring of the fluid is enhanced. This helps reduce particle migration, decreases segregation of particles and decreases the tendency of particles to form clusters. The higher particle loading also improves the dark color density when the dispersion is in the evanescent wave zone near the surface of the display, and this improves the image quality. The composition includes dispersants which are soluble in the liquid. The dispersants include KrytoX™ 157-FSL, KrytoX™ 157-FSM or KrytoX™ 157-FSH fluorinated oil (respectively having specified molecular weights of approximately 2500, 3500-4000 and 7000-7500, CAS Registry No. 860164-51-4, DuPont Performance Lubricants, Wilmington, Del. 19880-0023); they are shown below, and Zonyl fluorosurfactants, or Forafac fluorinated surfactants, DuPont Chemical Company, 1007 Market street, Wilmington, Del. 19898. Combinations of dispersants may be used. The dispersant concentration in the composition depends upon the concentration of pigment particles, and on the other components in the mixture. The weight ratio of dispersant to pigment in the composition is in the range of about 0.1 to about 3.0, and preferably about 1.0 to about 2.0. The dispersant in the composition is in the range of about 0.001 wt. % to about 70 wt. %, preferably about 2 wt. % to about 40 wt. % of the composition. The Krytox 157-FSH, Perfluroalkylpolyethercarboxylicacid (Mw 5000-7000) is represented as follows: 2,3,3,3-Tetrafluoro-2-heptafluoropropyloxy-propionic acid where n=1 Krytox™ 157-FSL (lower average molecular weight of above FSH, Mw 3500) The dispersant interacts with the surface of the particle to form a strong bond which anchors it to the surface, and the tail of the surfactant is highly soluble so it creates a barrier (generally through osmotic pressure) to prevent agglomeration with other particles. More than one dispersant can be used. The dispersant depends on the surface chemistry of the particle; the selection is made to optimize the interactions. For example, a dispersant with an acid functional group, like carboxylic acid, might be chosen for a particle containing basic functionality, like the quinacridone or pthalocyanine pigments, to obtain strong interactions. Likewise, a dispersant with a basic amine functional group, might be chosen for carbon black. At least one of the dispersants interacts by acid-base interactions to produce an ion pair (salt) with the surface of the light absorbing particle. In one embodiment, the particle surfaces are almost completely to completely covered with dispersant. Some of the dispersant needs to dissociate from the surface so the light absorbing particle is charged. Preferably the surface of the particle and dispersant should form pairs which saturate the surface, but upon saturation also enable a small degree of dissociation. This can be facilitated by allowing close packing with some steric constraint upon saturation. The charged particles will have electrostatic interactions as they move near each other. This will provide a barrier which inhibits agglomeration, and in conjunction with steric (osmotic pressure) interactions it will make a very stable suspension where the particles will not agglomerate. The degree of charging can be adjusted by varying the dispersant in the composition of the dispersion. The degree of dissociation will depend on the combination of solubility in the liquid, the strength of acid-base interaction, the molecular shape of dispersant and the molecular structure of the particle surface. Charging is also improved when the dissociated dispersants form micelles which help minimize the recombination of the ions, and this results is a higher degree of overall dissociation. In liquids with a low dielectric constant the double layer around charged particles (distance from the particle surface to charge neutrality) tends to be very large. This is because there are a very small number of ions in the liquid. As the particle spacing is decreased the charged particles will interact with each other, and this will create a suspension with a highly ordered structure. The spacing needed for the interaction will depend upon the magnitude of particle charge and the number of excess ions in solution, and these are controlled by the concentration and characteristics of the components used. Higher charging and lower concentrations of excess ions increase the strength of the interactions. The particles in this suspension interact with all nearest neighbors and this interaction inhibits their movement under low shear. In one embodiment, dispersants with either acidic or basic functional groups chosen to interact with the complementary basic or acidic functional groups on the surface of the light absorbing particle are used. This results in a composition containing charged light absorbing particles and only the counter ions for those charged groups, hence no excess ions. As a result the conductivity of the mixture is very low; this improves the structure and performance of the composition. It is preferable that the conductivity of the composition is low so the electrical power requirements of the device is minimized. In another embodiment, the dispersant contains functional groups on opposite ends of the backbone of the molecule. This enables it to become tethered to two different particles, and this prevents particle migration. The functional groups are chosen so they have strong interactions with the functional groups on the surfaces of the particles. The length of the molecule is chosen to allow some flexibility in movement, and in particular to allow the particle spacing to become compressed when the dispersion is placed in an electric field. The molecule also is long enough, and contains bulky enough and highly soluble branches along its backbone, ranging from methyl to dendritic structures which entrain the liquid and prevent particle agglomeration by osmotic pressure. In fluorinated liquids a fluorinated backbone is more soluble, so it is preferred in this embodiment. The concentration of this bi-functional dispersant is kept low enough so some functional groups on the surface of the light absorbing particles are available for interactions with mono-functional dispersants. These mono-functional dispersants contain acidic or basic functional groups which form salt pairs with the complementary acidic or basic functional groups on the light absorbing particle surfaces, and when they dissociate, the particle becomes charged. This composition of bi-functional and mono-functional dispersants combined with particles and liquid form an interlocked network. The particles will not form agglomerates or clusters nor will they migrate, and the network can expand or contract when placed in an electric field. In another embodiment, the particles in the composition are loosely flocculated, and they form a network. The ordered arrangement of particles depends on the size and packing of the particles. Flocculation occurs when the particle separation is less than the distance of van der Waals attractive forces which depends on the particle size and physical characteristics of the particle. These particles are still dispersed well enough to prevent tight agglomeration. This is accomplished by using a low molecular weight dispersant which covers the particle surface thoroughly. This dispersant is soluble in the liquid and has a short tail, in the range of about 4 to about 20 carbon atoms in length, and contains functional groups similar to those described previously, such as amines or carboxylic acid, and the like, which bond strongly onto the functional groups on the particle surfaces. Fluorinated dispersant molecules would be more soluble, and are preferred for fluorinated liquids. The composition may contain combinations of such dispersants. The flocculating agents are in the composition in the range of about 0% to the range of about 0.001 wt. % to about 70 wt. %, preferably about 2 wt. % to about 40 wt. % of the composition. The dispersants are chosen so all particles are well dispersed, but only the light absorbing particles are charged. If the particles are well dispersed, and the available space (in the liquid) is occupied by dissolved non-adsorbing polymer or other uncharged dispersed particles as previously described this can also create a suspension with a highly ordered structure. A polymer which is highly soluble in the liquid can cause the particles to form a highly ordered structured from attractive depletion forces and the effectiveness will depend on the relative size of the polymer radius of gyration and particle size combined with the concentration of each. This type of interaction can result is ordering with particle volume fractions as low as a few volume percent. At high concentrations non-adsorbing polymers in solution can stabilize particle suspensions (prevent agglomeration), and this can also result in an ordered structure at higher particle concentrations. The polymers include highly soluble forms of polyethylene, polypropylene, polyisobutylene, polystyrene or the like which do not adsorb onto the particles in the composition (no functional groups to interact with the functional groups on the particle surfaces), and they have a high molecular weight such that the radius of gyration is close to the radius of the light absorbing particles in the composition; these may be co-polymers or homo-polymers with branching to increase the entrainment of solvent—for fluorinated liquids partly or completely fluorinated polymers would be more soluble—in this embodiment it is preferred. The polymers would be in the molecular weight range from about one thousand Dalton (Da).to about one million Da., preferably about ten thousand Da. to about a few hundred thousand Da. The polymers may be used in combination. The polymer is in the composition in the range of about 0.1 wt. % to about 70 wt. %, preferably about 1 wt. % to about 20 wt. % of the composition. The composition may also include rheology control agents. These are soluble polymer molecules which become swollen by the liquid, and this causes an increase in the viscosity of the liquid; this decreases the mobility of particles. This helps prevent particle segregation and enhances the structure of the fluid. The swelling of the polymer will vary inversely with temperature, and this counterbalances the change in viscosity of the liquid with temperature. This helps maintain constant fluid flow properties with temperature changes, and this results in more consistent response time with variation of temperature. The rheology control agents include ethylene plus propylene copolymers, styrene plus butadiene copolymers, polymethacrylates, polyisobutenes and the like. Combinations may be used. The rheology agents are soluble in the liquid; fluorinated polymers would be more soluble in fluorinated liquids so it would be preferred in that embodiment. The polymers have molecular weights in the range from about 10,000 Da to about one million Da. The rheology control agents are in the composition in the range of about 0% (not present) to the range of about 0.01 wt. % to about 25 wt. %, preferably about 0.5 wt. % to about 15 wt. % of the composition. The composition may also include surface active agents (surfactants) which have a different function than the dispersants. These surfactants act as charging agents by forming salt pairs with larger molecules, like dispersants, in the composition, or they facilitate charging by forming micelles possibly in conjunction with other components in the composition. They increase particle charging by improving the dissociation of salt pairs by mediating the charge on the ion or associating with the ion to decrease the tendency to recombine with the counter-ion. They may also act as co-dispersants and occupy sites on the particle surface to help improve the total surface coverage. The surfactants include soluble small molecules with short tails and some polar groups, such as hydroxyl, substituted aromatics, carboxylic, amine, amide, as well as salts and aromatic groups and the like. The surfactants may be used in combination. The surfactants are in the composition in the range of about 0 wt. % to about 25 wt. % and in another embodiment in the range of about 0.01 wt. % to about 20 wt. % of the composition. In another embodiment, the composition is used to create a suspension which remains unagglomerated (no cluster formation) under conditions of operation without forming a structured fluid. In this case, the colloidal suspension is stabilized by having a tightly packed dispersant (surfactant) layer which is very strongly bound to the particle surface. This dispersant also has a high molecular weight tail that is very soluble in the liquid, and this inhibits agglomeration under severe conditions without forming a structured fluid. These suspensions will become structured at higher particle loadings, but the response time is too slow or optical properties are inadequate because particle motion is too severely limited. For example, when very high concentrations of dispersant (surfactant) are used, a highly structured dispersant(surfactant) layer can form on the surface of the solid. This tightly packed layer can include several dispersants, chosen to maximize coverage and strength of bonding to the surface of the particle. The light absorbing particles are charged in this composition because some of the dispersant which formed salt pairs on the particle surfaces has become dissociated, leaving a net charge. Overall the total amount of all the additives in the composition are in the range of about 0.1 wt. % to about 60 wt. %, preferably about 1 wt. % to about 40 wt. % and more preferably about 5 wt. % o about 30 wt. % of the composition. The colloidal dispersion of the composition has a structure which inhibits the particle migration from the low stress associated with gravitational segregation or caused by field gradients associated with reversing the electric field. This structure also inhibits aggregation of particles caused by strong collisions driven by a high electric field. The structured array of particles will become compressed and pushed away from one electrode and toward the other one when the field is applied. However, the forces associated with the structure will inhibit the compression of particles, and the higher particle concentration results in shorter distance traveled, therefore lower velocities will be reached, and there will be a reduction in agglomeration caused by the electric field. The structure will inhibit particle motion, but this is balanced by the optical properties required of the device. The composition contains particles that are spaced more closely together, and this increases particles interactions. It will also result in particles being near the prismatic surface. This is illustrated by FIG. 3B which shows a structured suspension 110 which has a uniform dispersion of particles 100 closely spaced. For example, for particles 100 with a diameter of about 150 nm the spacing will range from about 300 nm at a volume fraction of about 0.1 to about 130 nm for a volume fraction of about 0.25 and about 40 nm for a volume fraction of about 0.5. As the volume fraction increases the spacing becomes smaller than the particle diameter and the particles 100 will be well within about 0.25 micron of the evanescent wave zone adjacent the inward surfaces, of the prisms 94. As a result the particles 100 will absorb the incident light 108 causing a refractive index mismatch which frustrates TIR, giving the depicted pixel region a dark appearance to an observer who looks at sheet's 92 outer surface. When the electric field is applied, the structured suspension 110 of the composition becomes compressed 102 and moves away from the electrode surface 96; this is illustrated in FIG. 3A. For example, when a voltage source, not shown, is electrically connected between the upper and lower electrodes 96 and 98 to controllably apply a voltage across the uniform suspension 110, the spacing between particles 100 becomes reduced as the particles, in the uniform suspension 110, are squeezed away from the electrode 96 surface. This leaves a liquid film of low refractive index fluid 104 between the inward surface of upper sheet 92 and the compressed suspension 102, and it is sufficiently thick approximately 0.25 microns that it enables substantially all of the evanescent wave to be confined to a particle-free region of fluid and thus cause TIR 106, such that light which passes through the upper sheet 92 is reflected by TIR 106 at the interface, giving a white appearance to an observer who looks at sheet's 92 outward surface. It only requires a small displacement of the particles 100 in the composition to create a 0.25 micron thick film of liquid 104. When as depicted in FIG. 3b, the field is reversed, the particles 100 are pulled into the evanescent region and they frustrate the TIR 108 causing the depicted pixel region a dark appearance to an observer who looks at the outer surface of the sheet 92. The movement of particles into and out of the evanescent wave zone must be very rapid so that the transition of pixel color from white to dark happens very fast. The structure of the dispersion composition must be adequately strong to prevent migration under low stress; it must inhibit strong collisions under a high electric field, but it cannot reduce the speed of particle motion into and out of the evanescent zone near the electrode. The particle charge which helps create the ordered structure of the dispersion also causes electrophoretic motion of the particles. As the particle charge increases the electrophoretic velocity into and out of the evanescent zone will increase. These two effects—columbic interactions which promote a rigid structure and electrophoretic particle motion are linked together. The composition which promotes an ordered structure, including charging and close particle spacing also promotes the fast response to the electric field. The close particle spacing enables the change in color with minimal movement of particles, and the particle charging enables electrophoresis which becomes faster as the charge increases. Specific Embodiment The following examples demonstrate the composition and advantages of the present invention. The composition will control the structure, and the structure can be measured using rheology. Rheology is the measurement of the flow properties of a fluid. When a stress is applied to a fluid it will flow, and the measurement of shear stress with rate of shear will show the characteristics of that fluid. In particular, the rheology of a dispersion will show how the particles move in the liquid. The stress can be applied as an oscillation or as a continuous stress, and these measurements show different aspects about the structure. The composition of the mixture can be adjusted to modify its colloidal structure and obtain a suspension which does not form agglomerates or clusters, but still has a rapid response to the application of a low electric field; this dispersion has a specific type of rheology which helps to characterize its structure. This is illustrated in the following examples. Three mixtures R, S and V containing pigments, liquid and surfactant were made as described below. Formulation 1 Mixture R: 25.0 w % Pigment 12.5% w NRT-796D-Monastral Red-B 12.5% w Cromophtal Blue A3R 25.0% w KrytoX™ 157-FSH 50.0% w Krytox™ Oil Mixture S: 43.0w % Pigment 21.5% w NRT-796D-Monastral Red-B 21.5% w Cromophtal Blue A3R 14.0% w Krytox™ 157-FSH 43.0% w Krytox™ Oil Mixture V: 34.0% w Pigment 17.0% w NRT-796D-Monastral Red-B 17.0% w Cromophtal Blue A3R 19.5% w Krytox™ 157-FSH 46.5% w Krytox™ Oil Mixture V was made by mixing equal portions of R and S. These mixtures were each evaluated using a device with a design illustrated in FIG. 3A, and constructed with 25 μm prisms separated from a conductive substrate such that the average gap thickness was 75 μm. The mixtures were introduced into the gap between the microstructured surface and the rear substrate and the reflectance of light from the surface was measured when the device was subjected to a 1 Hz, 50 volt electrical pulse. The results of this measurement for the 3 mixtures are shown in FIG. 4. The graph in FIG. 4 shows that mixture S which has the highest pigment loading has the slowest response to the field. Mixture R which has the lowest pigment loading is faster than S, but mixture V has the fastest response. This is unexpected; one might expect that the response or speed of mixture V would be between S and R—since it is a mixture of the two. Further, on inspection of the components in the mixtures, mixture V has a higher concentration of components that would tend to increase the viscosity of the fluid. Hence one might expect that it should have a slower response, but it is faster. This result was investigated further from rheology measurements. A Carrimed CSL controlled stress rheometer was used for these measurements. A cone and plate configuration was used, and the measurements were done at 25° C. The results of these measurements are shown in the plot in FIG. 5: The upper curve in FIG. 5—rko179 is sample S; the middle curve, 187180-2 is sample V, and the bottom curve, rko-178 is sample R. The viscosity varies with shear rate in all cases, so these mixtures are non-Newtonian, and this indicates that the particle systems have some structure, or that the particles are interacting with each other. The higher viscosity and greater change with shear rate indicates that there is a greater degree of structure. Another way of interpreting this data is to fit it to a model which has parameters that relate to physical characteristics of the suspension. This data was fitted to two conventional models, the Herschel-Buckley model and the Cross model; the fitted parameters are shown in the Table I below: TABLE I Cross model H_B model zero shear Infinite Yield sample Pa-s shear, Pa-s stress, Pa Rate index V 27.73 3.394 3.131 .8653 R 1.874 .6769 1.291 .9683 S 4.81E05 24.43 24.71 .7026 The zero shear and infinite shear parameters represent the initial, unperturbed viscosity and viscosity of the continuous liquid phase respectively; the yield stress represents how much force is required to initiate movement—break a structure, and the rate index indicates how close to Newtonian (totally unstructured) the mixture is. Hence the sample with the highest concentration of pigment, sample S, has the strongest structure, and the sample with lowest pigment loading, sample R, has the weakest structure. This suggests that the intermediate level of structure is needed for the fastest response or movement of pigments in an electric field. A structure which is too strong impedes motion and this is what one might expect. However, the mixture with a weaker structure responds more slowly, and this is contrary to expectations. Perhaps the particles in the intermediate structured fluid can move in tandem and hence faster than those in the less structured fluid which may not be able to move in tandem because the structure is too weak. It's also possible that this is due to a combination of factors such as particle charge, inter-particle interactions and ratio of forces—which squeeze the liquid to push it out when the structured colloid is compressed. The structure must also inhibit particle motion under weaker, but long term stresses, such as gravity and diffusion induced by field gradients. Hence the mixture must be adjusted to reach the right combination, including particle spacing, particle charging, colloidal stability and liquid viscosity—in combination with the ability to move quickly in a strong field while remaining immobile in low shear. As will be apparent to those skilled in the art in light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof. The scope of the invention is to be construed in accordance with the substance defined by the following claims. | <SOH> BACKGROUND <EOH>In electrophoresis an ionically-charged particle moves through a medium due to the influence of an applied electric field. The concept of electrophoresis can be combined with the principles of ‘Total Internal Reflectance’ (TIR) to create addressable displays. A suspension of particles can be used to controllably frustrate TIR and switch the state of pixels in such displays in a cotrolled manner. For example, an electromagnetic field can be applied to move charged particles in the suspension through an electrophoretic medium toward or away from an evanescent wave region to frustrate TIR at selected pixel portions of the region. In order for the electronic display to be useful the display should have quick response times. Further it is desirable that there is good contrast between the dispersed particles and the white background and that the electrophoretically active suspension remains stable. It is known that repeated switching of a display which utilizes electrophoretically-mobile particles can result in a non-uniform distribution or movement of the particles, gradually causing the formation of particle clusters which deteriorates the quality of images produced by the display over time. An example is found in Dalisa, A., “Electrophoretic Display Technology,” IEEE Transactions on Electron Devices, Vol. 24, 827-834, 1977; and Mürau et al, “The understanding and elimination of some suspension instabilities in an electrophoretic display,” J. Appl. Phys., Vol. 49, No. 9, September 1978, pp. 4820-4829. It has been shown that such undesirable clustering can be reduced by encapsulating groups of suspended particles in separate micro-fluidic regions. See for example Nakamura et al, “Development of Electrophoretic Display Using Microencapsulated Suspension,” Society for Information Display Symposium Proceedings, 1014-1017, 1998 and Drzaic et al, “A Printed and Rollable Bistable Electronic Display,” Society for Information Display Symposium Proceedings, 1131-1134, 1998. In summary it is desirable for an electronic display to have long term stability, quick response time and high contrast between the background and image being displayed. The invention has discovered that certain compositions have a combination of physical properties which overcome these obstacles in particular on electrophoresis. | <SOH> SUMMARY OF INVENTION <EOH>The inventive composition creates a structured fluid which improves the response time, visible image and long-term image stability of an electrophoretically-mobile particle display. The composition comprises 1) a low refractive index liquid, which is the electrophoretic medium 2) particles selected from the group consisting of light absorbing particles such as pigments which are charged, non-light absorbing uncharged particles which increase the viscosity such as, teflon, silica, alumina and the like and combinations thereof, 3) additives which include a) dispersants, b) charging agents, c) surfactants (also interchangeable with the term surface action agents), d) flocculating agents, e) polymers and f) and combinations thereof. The composition is used to improve response time to form a display image after application of an electric field. The composition forms a structured suspension of particles in which the particles are stable from agglomeration. The particles interact through colloidal forces controlled by the composition which inhibits particle motion under low stress caused by gravity or by the osmotic flow of ions in an electric field induced by reversing the electric field as the display's pixels are switched between reflective and non-reflective states, without encapsulating the ink in isolated compartments. | 20040123 | 20060718 | 20050728 | 66750.0 | 0 | SPECTOR, DAVID N | STRUCTURED FLUID COMPOSITIONS FOR ELECTROPHORETICALLY FRUSTRATED TOTAL INTERNAL REFLECTION DISPLAYS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,764,120 | ACCEPTED | Alternator cover shield | An alternator cover shield which is designed to close the starter pulley opening or cavity in an alternator cover when the recoil assembly has been removed. The alternator cover shield is characterized by a flat, typically transparent plate fitted with spaced-apart peripheral plate openings for receiving mount bolts that typically extend through aligned openings in a correspondingly-shaped gasket interposed between the plate and the alternator cover face to facilitate securing the plate on the alternator cover and preventing dirt, debris, water and the like from entering the starter pulley cavity. The weep hole in the alternator cover is sealed with a plug and a pulley nipple is inserted in the pulley opening located in the alternator cover at the base of the starter pulley cavity and bolted in place to seal the pulley opening. A method of sealing the cavity in an alternator cover against the intrusion of foreign matter, which includes the steps of removing the recoil assembly and starter pulley from the cavity and the pulley opening, respectively, inserting a pulley nipple in the pulley opening, closing the cavity with a sealing plate and inserting a plug in the weep hole of the alternator cover. | 1. An alternator cover shield for closing in the alternator cover of an alternator, comprising a shield adapted for mounting on the alternator cover and a seal interposed between said shield and the alternator cover for sealing said shield on the alternator cover. 2. The alternator cover shield of claim 1 wherein the alternator cover has a weep hole and comprising a plug for sealing the weep hole in the alternator cover. 3. The alternator cover shield of claim 1 wherein said seal comprises a gasket and comprising gasket openings provided in said gasket and shield openings provided in said shield, said gasket openings aligned with said shield openings, and fasteners extending through said shield openings and said gasket openings and said fasteners engaging the alternator cover for removably mounting said shield and said gasket on the alternator cover. 4. The alternator cover shield of claim 3 wherein the alternator cover has a weep hole and comprising a plug sealing the weep hole in the alternator cover. 5. The alternator cover shield of claim 4 wherein said fasteners comprise bolts for threadably engaging the alternator cover and removably mounting said shield and said gasket on the alternator cover. 6. The alternator cover shield of claim 1 wherein the alternator cover has a pulley mount opening and comprising a pulley nipple extending into the pulley mount opening of the alternator cover for sealing the pulley mount opening. 7. The alternator cover shield of claim 6 wherein said seal comprises a gasket and comprising gasket openings provided in said gasket and shield openings provided in said shield, said gasket openings aligned with said shield openings and mount bolts extending through said shield openings and said gasket openings and threaded into the alternator cover for removably mounting said shield and said gasket on the alternator cover. 8. The alternator cover shield of claim 7 wherein the alternator cover has a weep hole and comprising a plug sealing the weep hole in the alternator cover. 9. A shield for covering and sealing the starter pulley cavity of an engine alternator cover having a pulley mount opening communicating with the starter pulley cavity, said shield comprising a plate shaped for disposition on the alternator cover and over the starter pulley cavity; a gasket interposed between said plate and the alternator cover for sealing the starter pulley cavity from intrusion of undesirable environmental elements; at least one fastener engaging said plate and the alternator cover for securing said plate and said gasket on the alternator cover; and a pulley nipple extending into the pulley mount opening of the alternator cover for sealing the pulley mount opening. 10. The shield of claim 9 comprising gasket openings provided in said gasket and plate openings provided in said plate, said gasket openings aligned with said plate openings, and wherein said at least one fastener comprises at least two mount bolts extending through said plate openings and said gasket openings and threaded into the alternator cover for removably mounting said plate and said gasket on the alternator cover. 11. The shield of claim 9 wherein the alternator cover has a weep hole and comprising a plug for sealing the weep hole in the alternator cover. 12. The shield of claim 9 wherein the alternator cover has a weep hole and comprising: (a) gasket openings provided in said gasket and plate openings provided in said plate, said gasket openings aligned with said plate openings, and wherein said at least one fastener comprises at least two mount bolts extending through said plate openings and said gasket openings and into the alternator cover for threadably mounting said plate and said gasket on the alternator cover; and (b) a resilient plug for sealing the weep hole in the alternator cover. 13. A shield for mounting on the alternator cover of an engine and shielding the alternator cover interior and pulley mount opening from water and particulate matter intrusion, said shield comprising a substantially flat plate shaped for seating on the alternator cover; spaced-apart plate mount openings provided in said plate; a gasket interposed between said plate and the alternator cover; spaced-apart gasket openings provided in said gasket, said gasket openings matching said plate mount openings in said plate; mount bolts extending through said plate openings and said gasket openings and into the alternator cover for removably securing said plate and said gasket on the alternator cover; and a pulley nipple bolted in the pulley mount opening of the alternator cover for removably sealing the pulley mount opening. 14. The shield of claim 13 wherein the alternator cover has a weep hole and comprising a rubber plug for sealing the weep hole of the alternator cover. 15. A method of sealing the starter pulley cavity of an engine alternator cover comprising the steps of: (a) removing the recoil assembly from the alternator cover; (b) removing the starter pulley from the pulley mount opening in the starter pulley cavity; (c) inserting a pulley nipple in the pulley mount opening; and (d) mounting a plate on the alternator cover for closing the starter pulley cavity. 16. The method according to claim 15 comprising the step of inserting a plug in the weep hole of the alternator cover. 17. The method of claim 16 comprising the step of interposing a gasket between said plate and the alternator cover. 18. The method according to claim 16 comprising the steps of: (a) inserting a plug in the weep hole of the alternator cover; and (b) interposing a gasket between said plate and the alternator cover. | SUMMARY OF THE INVENTION This invention relates to all-terrain vehicles (ATV) and more particularly, to an alternator cover shield or plate and method for replacing the conventional recoil mechanism or assembly on an alternator cover when the recoil assembly is rendered inoperable by the intrusion of dirt, water, grime and the like into the alternator cover cavity. Such intrusion makes it difficult or impossible to operate the rewind mechanism, rotate the starter pulley and manually start the ATV engine. Since ATV engines also have an automatic starter powered by a battery, the recoil assembly mechanism is not essential to the operation of the ATV and may be quickly and easily replaced by the alternator cover shield of this invention by simply removing the recoil assembly bolts, removing the recoil assembly, loosening the pulley bolt, removing the starter pulley, replacing the starter pulley with a pulley nipple, fitting the shield and underlying gasket to the alternator cover mount face and bolting the alternator cover shield in place over the gasket. The starter pulley is replaced by using the pulley bolt to secure a pulley nipple that may be splined or smooth and fits in the pulley opening at the base of the cover cavity in the alternator cover, where it is bolted in place with an O-ring or seal washer. The splined end of a splined pulley nipple engages the drive gear in the engine assembly and rotates with the pulley nipple bolt, while a smooth nipple may be sized to prevent contact with the rotating flywheel. A rubber plug typically seals the conventional weep hole provided in the alternator cover to further prevent intrusion of undesirable dirt, grime or water into the alternator cavity cover through that opening. The alternator cover shield is typically flat and may be constructed of a clear plastic material or the like, according to the knowledge of those skilled in the art, in order to view the alternator cover cavity and determine whether any water, dirt, or grime intrusion has occurred. Alternatively, the alternator cover shield can be constructed of metal, fiberglass or other materials, further according to the knowledge of those skilled in the art. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood by reference to the accompanying drawings, wherein: FIG. 1 is a perspective view of a conventional all-terrain vehicle (ATV) alternator cover with a preferred embodiment of the alternator cover shield mounted in functional configuration thereon; FIG. 2 is a perspective view of a typical ATV alternator cover with a conventional recoil assembly bolted thereon; FIG. 3 is an exploded view of the conventional recoil assembly components and alternator cover illustrated in FIG. 2; FIG. 4 is an exploded view of the alternator cover and the alternator cover shield illustrated in FIG. 1; and FIG. 5 is an exploded view of the pulley nipple component illustrated in FIG. 4. DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring initially to FIGS. 1, 4 and 5 of the drawings the alternator cover shield of this invention is generally illustrated by reference numeral 1. The alternator cover shield 1 includes a typically flat cover shield 5, which may be constructed of a transparent plastic or a metal, fiberglass or other material, in non-exclusive particular, along with a gasket 2 which is preferably configured like the cover shield 5 and interposed between the cover shield 5 and the mount face 116b of an alternator cover 16 (FIG. 4). Gasket bolt openings 3 are spaced-apart in the gasket 2 and are aligned with corresponding cover shield bolt openings 6 provided in the cover shield 5, for receiving mount bolts 30 which are threaded into the corresponding, internally-threaded cover bolt holes 116c, provided in the mount face 116b of the alternator cover 16, as further illustrated in FIG. 4. Accordingly, it will be apparent from a consideration of FIGS. 1 and 4 that the cover shield 5 can be tightly sealed against the gasket 2 on the mount face 116b of the alternator cover 16 by tightening the mount bolts 30. This fitting of the cover shield 5 to the alternator cover 16 seals the cover cavity 16a (FIG. 4) of the alternator cover 16 against the intrusion of dirt, grime, water and other undesirable components, under circumstances where the weep hole 28, provided in the alternator cover 16, is also sealed, typically by a flexible resilient rubber plug 14 (FIG. 5). Referring now to FIGS. 1-5 of the drawings the cover shield 5 is designed to replace a recoil assembly 25, fitted with a starter pulley 18 and a rewind cord or rope (not illustrated) having a recoil rope handle 27, as illustrated in FIGS. 2 and 3. A nipple 8 may be shaped from a starter pulley 18, or otherwise manufactured with or without the splines 11 and seated in a pulley opening 17 provided in the alternator cover 16 at the base of the cover cavity 16a, by means of a pulley bolt 22, having a bolt head 23, typically seated on a bolt O-ring 24 (FIGS. 4 and 5). The conventional starter pulley 18 component of the recoil assembly 25 is illustrated in FIG. 3 and includes a starter pulley plate 19, having upward-standing, spaced-apart flanges 20 for engaging a corresponding spring-loaded mechanism (not illustrated) also located in the recoil assembly 25, which mechanism is activated by pulling the recoil rope handle 27 outwardly of the recoil assembly 25 to start the ATV engine (not illustrated) in conventional fashion (FIG. 2). The pulley nipple 8 typically includes a nipple base 9, extending from a base flange 10 and a nipple bore 12 for accommodating the pulley bolt 22. Referring now to FIGS. 1, 4 and 5 of the drawings, under circumstances where the alternator cover shield 1 is used to replace the recoil assembly 25 on the alternator cover 16, the pulley nipple 8 may be constructed by removing the starter pulley plate 19 and the plate flanges 20 of the starter pulley 18, or otherwise manufactured by techniques known to those skilled in the art. The pulley nipple 8 is then seated in the pulley opening 17, as in the conventional arrangement illustrated in FIG. 3, and is bolted in place using the same pulley bolt 22 and a bolt O-ring 24. Accordingly in one embodiment the splines 11, fitted on the extending end of the pulley nipple 8, engage a drive gear (not illustrated) in the engine (not illustrated) in the same manner as in the conventional mechanical configuration wherein the conventional starter pulley 18 is utilized. The bolt O-ring 24 typically seats in the bolt head 23 against the base flange 10 of the pulley nipple 8, to seal the pulley opening 17 from intrusion of dirt, grime, water or other undesirable components which may migrate into the cover cavity 16a of the alternator cover 16. Accordingly, it will be appreciated from a consideration of FIGS. 1, 4 and 5 that the cover shield 5 and the plug 14 prevent intrusion of water, dirt, grime or other undesirable components or elements into the cover cavity 16a of the alternator cover 16 when the pulley nipple 8 is mounted in the pulley mount opening 17 (FIGS. 4 and 5) and the cover shield 5 is sealed in the position illustrated in FIG. 1. Under these circumstances, the drive gear (not illustrated) is operated by electrical means in conventional fashion through a suitable mechanical and electrical arrangement in the all-terrain vehicle engine (not illustrated). The alternator cover shield of this invention thus serves to replace the recoil assembly 25 in an ATV engine and prevent further water, dirt, grime or other undesirable element intrusion into the cover cavity 16a of the alternator cover 16 during operation of the ATV. While the preferred embodiments of the invention have been described above, it will be recognized and understood that various modifications may be made in the invention and the appended claims are intended to cover all such modifications which may fall within the spirit and scope of the invention. | <SOH> SUMMARY OF THE INVENTION <EOH>This invention relates to all-terrain vehicles (ATV) and more particularly, to an alternator cover shield or plate and method for replacing the conventional recoil mechanism or assembly on an alternator cover when the recoil assembly is rendered inoperable by the intrusion of dirt, water, grime and the like into the alternator cover cavity. Such intrusion makes it difficult or impossible to operate the rewind mechanism, rotate the starter pulley and manually start the ATV engine. Since ATV engines also have an automatic starter powered by a battery, the recoil assembly mechanism is not essential to the operation of the ATV and may be quickly and easily replaced by the alternator cover shield of this invention by simply removing the recoil assembly bolts, removing the recoil assembly, loosening the pulley bolt, removing the starter pulley, replacing the starter pulley with a pulley nipple, fitting the shield and underlying gasket to the alternator cover mount face and bolting the alternator cover shield in place over the gasket. The starter pulley is replaced by using the pulley bolt to secure a pulley nipple that may be splined or smooth and fits in the pulley opening at the base of the cover cavity in the alternator cover, where it is bolted in place with an O-ring or seal washer. The splined end of a splined pulley nipple engages the drive gear in the engine assembly and rotates with the pulley nipple bolt, while a smooth nipple may be sized to prevent contact with the rotating flywheel. A rubber plug typically seals the conventional weep hole provided in the alternator cover to further prevent intrusion of undesirable dirt, grime or water into the alternator cavity cover through that opening. The alternator cover shield is typically flat and may be constructed of a clear plastic material or the like, according to the knowledge of those skilled in the art, in order to view the alternator cover cavity and determine whether any water, dirt, or grime intrusion has occurred. Alternatively, the alternator cover shield can be constructed of metal, fiberglass or other materials, further according to the knowledge of those skilled in the art. | 20040126 | 20060214 | 20050728 | 94321.0 | 0 | LE, DANG D | ALTERNATOR COVER SHIELD | SMALL | 0 | ACCEPTED | 2,004 |
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10,764,179 | ACCEPTED | Systems and methods for operating logic circuits | Systems and methods for reducing the power consumption of some combinations of logic gates by reducing the number of unnecessary transitions that are made by logic gates that do not affect the output of the logic. In one embodiment, a modified exclusive-OR (XOR) gate is coupled to a modified multiplexer. The XOR gate has two inputs, Ain, and Bin, and an output, XORout, which is provided as an input to the multiplexer. Another input to the multiplexer is Cin. A select signal is input to the multiplexer to select either Cin or XORout to be provided at the output of the multiplexer. If XORout is selected, the XOR gate operates in a first mode in which it functions as a normal XOR gate. If Cin is selected, the XOR gate operates in a second mode in which the XOR gate uses less power than when the XOR gate operates normally. | 1. A system comprising: a first logic circuit configured to receive one or more logic circuit input signals and to generate a logic circuit output signal; and a multiplexer configured to receive the logic circuit output signal and one or more additional signals as multiplexer input signals, wherein the multiplexer is configured to receive a select signal that controls the multiplexer to select one of the multiplexer input signals to be provided as a multiplexer output signal; wherein when the select signal controls the multiplexer to select the logic circuit output signal as the multiplexer output signal, the first circuit operates in a first mode, and when the select signal controls the multiplexer to deselect the logic circuit output signal as the multiplexer output signal, the first circuit operates in a second mode. 2. The system of claim 1, wherein the second mode comprises a power-saving mode. 3. The system of claim 1, wherein when the first logic circuit operates in the second mode, the logic circuit output signal contains fewer data transitions than when the first logic circuit operates in the first mode. 4. The system of claim 3, wherein when the first logic circuit operates in the second mode, the logic circuit output signal contains no data transitions. 5. The system of claim 1, wherein the first logic circuit operates according to a first truth table in the first mode and according to a second truth table in the second mode, and wherein the first truth table is not identical to the second truth table. 6. The system of claim 1, wherein the first logic circuit functions as an XOR gate in the first mode. 7. The system of claim 1, wherein the first logic circuit functions as an XNOR gate in the first mode. 8. The system of claim 7, wherein the multiplexer is configured to invert the logic circuit output signal when the first logic circuit is selected. 9. The system of claim 1, wherein the multiplexer is configured to receive only 2 multiplexer input signals. 10. The system of claim 1, wherein the multiplexer is configured to receive more than 2 multiplexer input signals. 11. A method comprising: providing a first logic circuit configured to receive one or more logic circuit input signals and to generate a logic circuit output signal; providing a multiplexer configured to receive the logic circuit output signal and one or more additional signals as multiplexer input signals, wherein the multiplexer is configured to receive a select signal that controls the multiplexer to select one of the multiplexer input signals to be provided as a multiplexer output signal; and operating the first logic circuit in a first mode when the first logic circuit is selected by the multiplexer and operating the first logic circuit in a second mode when the first logic circuit is deselected by the multiplexer, wherein the operation of the first logic circuit is different in the first and second modes. 12. The method of claim 11, wherein the second mode comprises a power-saving mode. 13. The method of claim 11, further comprising reducing data transitions in the first logic circuit in the second mode, as compared to the first mode. 14. The method of claim 13, further comprising eliminating data transitions in the first logic circuit in the second mode. 15. The method of claim 11, operating the first logic circuit according to a first truth table in the first mode and according to a second truth table in the second mode, wherein the first truth table is not identical to the second truth table. 16. The method of claim 11, operating the first logic circuit as an XOR gate in the first mode. 17. The method of claim 11, operating the first logic circuit as an XNOR gate in the first mode. 18. The method of claim 17, inverting the logic circuit output signal when the first logic circuit is selected. 19. The method of claim 11, controlling the multiplexer to select from only 2 multiplexer input signals. 20. The method of claim 11, controlling the multiplexer to select from more than 2 multiplexer input signals. | BACKGROUND OF THE INVENTION Digital logic circuits are widely used in electronic systems. These systems may be very simple systems, such as individual logic gates that are used for simple control circuits. They may also include moderately complex systems, such as integrated logic circuits that are used for controllers are embedded processors. These systems may also include processors that are much more complex and are used in powerful computing systems. These digital electronic systems are typically designed primarily in terms of the logic functions that are performed by their various subsystems and components. In other words, the design of the system focuses on the logic that will be used by the system to handle input, output, control and other information. The logic design is based upon the use of logic gates, such as AND, OR, NAND, NOR, XOR and various other types of gates. While these gates are, from the perspective of the logic design, the basic building blocks of the hardware logic of the system, it is important to keep in mind that each of these gates typically comprises transistors and various other electronic components that are combined to form the logic gate. The electronic components that form the gates of the digital logic require power to operate. In other words, the logic gates are not simply passive devices that require no power to produce a desired output from a given input. Because of the increasing number of logic gates and corresponding electronic components in systems such as data processors, the amount of power that is required by the electronic components is increasingly a concern in the design of these systems. Accordingly, it is, as a general matter, always desirable to provide new ways to reduce the amount of power that is required by the system. Even a small power savings at the electronic component (sub-gate) level may translate to a large power savings at the system level because of the large number of electronic components within the system. SUMMARY OF THE INVENTION One or more of the problems outlined above may be solved by the various embodiments of the invention. Broadly speaking, the invention comprises systems and methods for reducing the power consumption of some combinations of logic gates by reducing the number of unnecessary transitions that are made by logic gates that do not affect the output of the logic. One embodiment of the invention comprises a system including a first logic circuit configured to receive one or more logic circuit input signals and to generate a logic circuit output signal; and a multiplexer configured to receive the logic circuit output signal and one or more additional signals as multiplexer input signals. The multiplexer is configured to also receive a select signal that controls the multiplexer to select one of the multiplexer input signals to be provided as a multiplexer output signal. When the select signal controls the multiplexer to select the logic circuit output signal as the multiplexer output signal, the first circuit operates in a first mode, and when the select signal controls the multiplexer to deselect the logic circuit output signal as the multiplexer output signal, the first circuit operates in a second mode. In one embodiment, the first logic circuit is a modified XOR gate and the second mode is a power saving mode in which the data transitions in the output of the XOR gate are eliminated to reduce the power used by the XOR gate. An alternative embodiment of the invention comprises a method including the steps of providing a first logic circuit configured to receive one or more logic circuit input signals and to generate a logic circuit output signal, providing a multiplexer configured to receive the logic circuit output signal and one or more additional signals as multiplexer input signals and to receive a select signal that controls the multiplexer to select one of the multiplexer input signals to be provided as a multiplexer output signal. The method further includes operating the first logic circuit in a first mode when the first logic circuit is selected by the multiplexer and operating the first logic circuit in a second mode when the first logic circuit is deselected by the multiplexer. In one embodiment, the first logic circuit is a modified XOR gate and the second mode is a power saving mode in which the data transitions in the output of the XOR gate are eliminated to reduce the power used by the XOR gate. Numerous additional embodiments are also possible. BRIEF DESCRIPTION OF THE DRAWINGS Other objects and advantages of the invention may become apparent upon reading the following detailed description and upon reference to the accompanying drawings. FIG. 1 is a diagram illustrating the interconnection of an XOR gate and a multiplexer. FIG. 2 is a truth table showing the output (XORout) of an XOR gate corresponding to each possible pair of inputs (Ain, Bin) FIG. 3 is a truth table showing the output (MUXout) of a multiplexer corresponding to each possible set of inputs (XORout, Cin, Sel). FIG. 4 is a truth table showing the output (MUXout) and an intermediate signal (XORout) of a combination of an XOR gate and a multiplexer corresponding to each set of inputs (Ain, Bin, Cin, Sel) FIG. 5 is a diagram illustrating the electrical components of one design for a XOR-multiplexer combinational logic circuit in accordance with the prior art. FIG. 6 is a diagram illustrating the electrical components of a modified XOR-multiplexer combinational logic circuit in accordance with one embodiment of the invention. FIG. 7 is a truth table showing the output (MUXout) and an intermediate signal (XNORout) of a combination of a modified XOR gate and a modified multiplexer corresponding to each set of inputs (Ain, Bin, Cin, Sel). FIG. 8 is a diagram illustrating the electrical components of an alternative design for a XOR-multiplexer combinational logic circuit in accordance with the prior art. FIG. 9 is a diagram illustrating the electrical components of a modified XOR-multiplexer combinational logic circuit in accordance with an alternative embodiment of the invention. FIG. 10 is a diagram illustrating the electrical components of a modified XOR-multiplexer combinational logic circuit in accordance with another alternative embodiment of the invention. FIG. 11 is a diagram illustrating the electrical components of a modified XOR-multiplexer combinational logic circuit in accordance with yet another alternative embodiment of the invention. FIG. 12 is a diagram illustrating the electrical components of a modified XOR-multiplexer combinational logic circuit in accordance with yet another alternative embodiment of the invention. FIG. 13 is a diagram illustrating the electrical components of a modified XOR-multiplexer combinational logic circuit in accordance with yet another alternative embodiment of the invention. FIG. 14 is a diagram illustrating the electrical components of a modified XOR-multiplexer combinational logic circuit in accordance with yet another alternative embodiment of the invention. FIG. 15 is a diagram illustrating the electrical components of a modified XOR-multiplexer combinational logic circuit in accordance with yet another alternative embodiment of the invention. While the invention is subject to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and the accompanying detailed description. It should be understood, however, that the drawings and detailed description are not intended to limit the invention to the particular embodiments which are described. This disclosure is instead intended to cover all modifications, equivalents and alternatives falling within the scope of the present invention as defined by the appended claims. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS One or more embodiments of the invention are described below. It should be noted that these and any other embodiments described below are exemplary and are intended to be illustrative of the invention rather than limiting. As described herein, various embodiments of the invention comprise systems and methods for reducing the power consumption of some combinations of logic gates by reducing the number of unnecessary transitions that are made by logic gates that do not affect the output of the logic. In one embodiment, the combination of logic gates comprises a modified exclusive-OR (XOR) gate coupled to a modified multiplexer. In this embodiment, the XOR gate has two inputs: Ain; and Bin. The output of the XOR gate is provided as an input to the multiplexer. Another input to the multiplexer is Cin. A select signal is input to the multiplexer to control whether the multiplexer selects Cin or the output of the XOR gate to provide at the output of the multiplexer. If the output of the XOR gate is selected, the XOR gate operates in a first mode in which it functions as a normal XOR gate. If Cin is selected, the XOR gate operates in a second mode in which the XOR gate uses less power than when the XOR gate operates normally. When the output of the XOR gate is not selected by the multiplexer, it doesn't matter what information is output by the XOR gate. The XOR gate can therefore provide incorrect output information (i.e., information that does not follow the truth table for an XOR gate). Consequently, the XOR gate can be configured to perform in a manner that reduces the amount of power drawn by the gate (i.e., a power saving mode) or that provides some other advantage over normal operation. In one embodiment, the XOR gate is configured to eliminate data transitions that would normally occur in the output of the XOR gate. These data transitions cause corresponding spikes in the power drawn by the XOR gate. By eliminating the data transitions when the XOR gate is deselected, less power is used by the XOR gate. Referring to FIG. 1, a diagram illustrating the interconnection of an XOR gate and a multiplexer is shown. XOR gate 110 has two inputs. A first logic signal, Ain, is coupled to one of the inputs, while a second logic signal, Bin, is coupled to the other of the inputs. The XOR gate 110 is coupled to multiplexer 120 so that the output of XOR gate 110 is provided as an input to multiplexer 120. A third logic signal, Cin, is coupled to a second input to multiplexer 120. Multiplexer 120 also has a control input coupled to receive a select signal, Sel. Ain, Bin, Cin and Sel are all binary signals. That is, each of these signals takes one of two values: 0 or 1. Ain and Bin are processed by XOR gate 110 to generate a binary output signal, XORout. Multiplexer 120 selects this signal (XORout) or Cin, depending upon the state of select signal Sel, and provides the selected signal at the output of the multiplexer as signal MUXout. The signal output by XOR gate 110 (XORout) based upon input signals Ain and Bin is defined by the truth table shown in FIG. 2. The signal output by multiplexer 120 (MUXout) based upon input signals XORout, Cin and Sel is defined by the truth table shown in FIG. 3. As can be seen in FIG. 3, the output of multiplexer 120 (MUXout) is dependent only upon the selected input signal. The deselected signal (i.e., the signal that is not selected) has no effect on the output (MUXout). Thus, when Cin is selected and XORout is deselected, Cin, is passed through multiplexer 120 and provided at the output of the multiplexer as MUXout. On the other hand, when XORout is selected and Cin is deselected, XORout is passed through multiplexer 120 and provided at the output of the multiplexer as MUXout. When XOR gate 110 and multiplexer 120 are combined as shown in FIG. 1, they may be viewed as a single combinational logic circuit having inputs Ain, Bin, Cin and Sel, and output MUXout. The truth table for this combinational logic circuit is shown in FIG. 4. This table includes the values of intermediate signal XORout. As noted above, logic gates such as XOR gate 110 and multiplexer 120 are themselves based upon electronic components such as transistors, inverters, and so on. For example, one prior art implementation of an XOR-multiplexer combinational logic circuit as shown in FIG. 1 is illustrated in FIG. 5. Referring to FIG. 5, a diagram illustrating the electrical components of a XOR-multiplexer combinational logic circuit in accordance with the prior art is shown. The circuit includes a group of components forming XOR gate 510 and a group of components forming multiplexer 520. It should be noted that XOR gate 510 makes use of not only signal Ain, but also signals B and B_b. In this embodiment, signal B is equal to signal Bin, while signal B_b is the inverse of Bin. The signals B_b and B are generated by inverting Bin once and twice, respectively, using circuitry 530. Circuitry 530 is illustrated separately here in order to simplify the illustration of XOR gate 510 (by minimizing the crossing of electrical interconnections between the components). XOR gate 510 consists of an inverter 511 and six transistors, 512-517. Three of the transistors (512, 514 and 515) are PMOS transistors, while the other three (513, 516 and 517) are NMOS transistors. Ain is input to inverter 511, and the inverted signal is coupled through transistors 512 and 513 to the output of XOR gate 510. If one of transistors 512 or 513 is turned on, the output of inverter 511 is effectively directly coupled to the output of XOR gate 510. If both of transistors 512 and 513 are turned off, the output of inverter 511 is effectively isolated from the output of XOR gate 510. Transistors 512 and 513 are turned on and/or off by signals B and B_b, respectively. It should be noted that transistors 512 and 513 are placed back-to-back in the diagram of FIG. 5 for the purpose of simplifying the diagram. Transistors 512 and 513 therefore appear as a square with a bar on the side of NMOS transistor 513 and a bar with a circle on the side of PMOS transistor 512. This same method of illustrating back-to-back transistors is used in the other figures as well. If the output of inverter 511 is isolated from the output of XOR gate 510, the output of XOR gate 510 is controlled by whether transistors 514-517 are turned on or off, thereby coupling the output of the XOR gate to either Vcc (binary 1) or ground (binary 0). Transistors 514-517 are turned on/off by signals B, Ain, Ain and B_b, respectively. It should be noted that the PMOS transistors are turned on when the respective signals are 0, and off when the respective signals are 1. Conversely, the NMOS transistors are turned on when the respective signals are 1, and off when the respective signals are 0. XOR gate 510 implements the truth table of FIG. 2. XOR gate 510 operates as follows. When Ain and Bin are both 0 (and B is 0 and B_b is 1), both transistor 512 and transistor 513 are turned off, isolating the output of inverter 511 from the output of XOR gate 510. Because Ain is 0, a 1 is applied to transistors 515 and 516, so transistor 515 is turned off and transistor 516 is turned on. A 0 is applied to transistor 514, turning it on, and a 1 is applied to transistor 517, turning it on as well. The output of XOR gate 510 is therefore coupled to ground through transistors 516 and 517, both of which are turned on. The output of XOR gate 510 is isolated from Vcc by transistor 515, which is turned off. Thus, for Ain and Bin equal to 0, the output of XOR gate 510 is 0. When Ain equals 0 and Bin equals 1, a 0 is applied to transistor 512, while a 1 is applied to transistor 513, turning both of these transistors on. This effectively couples the output of inverter 511 to the output of XOR gate 510. 1's are applied to transistors 514 and 515, turning both of these transistors off. A 1 is also applied to transistor 516, thereby turning it on. A 0 is applied to transistor 517, turning this transistor off. Because both of transistors 514 and 515 are turned off, the output of XOR gate 510 is isolated from Vcc. Because transistor 517 is turned off, the output of XOR gate 510 is also isolated from ground, even know transistor 516 is turned on. Thus, for Ain equal to 0 and Bin equal to 1, the output of XOR gate 510 is 1. When Ain equals 1 and Bin equals 0, a 1 is applied to transistor 512 and a 0 is applied to transistor 513, turning both of these transistors off. The output of inverter 511 is therefore isolated from the output of XOR gate 510. 0's are applied to transistors 514 and 515, turning them on. The output of XOR gate 510 is therefore coupled to Vcc. A 0 is applied to transistor 516, turning it off. A 1 is applied to transistor 517, turning it on. Because transistor 516 is off, the output of XOR gate 510 is isolated from ground, even transistor 517 is on. Thus, for Ain equal to 1 and Bin equal to 0, the output of XOR gate 510 is 1 When Ain equals 1 and Bin equals 1, a 0 is applied to transistor 512, while a 1 is applied to transistor 513, turning both of these transistors on. This effectively couples the output of inverter 511 to the output of XOR gate 510. A 1 is applied to transistor 514, turning it off. A 0 is applied to transistor 515, turning it on. A 0 is applied to transistor 516, thereby turning it off. A 0 is applied to transistor 517, turning this transistor off. Because both of transistors 516 and 517 are turned off, the output of XOR gate 510 is isolated from ground. Because transistor 514 is turned off, the output of XOR gate 510 is also isolated from Vcc, even though transistor 515 is turned on. Thus, for Ain equal to 1 and Bin equal to 1, the output of XOR gate 510 is 0. Multiplexer 520 implements the truth table of FIG. 3. Multiplexer 520 operates as follows, where Sel_b is the inverse of select signal Sel. When select signal Sel is 0 (and Sel_b is 1), one of the two inputs to NAND gate 521 is a 0, so the output of NAND gate 521 will be 1, regardless of the other input. Thus, whether the output of XOR gate 510 is a 0 or a 1, the output of NAND gate 521 will be 1. Since one of the inputs to NAND gate 522 is 1, the output of NAND gate 522 will depend upon the other input to the gate (Cin). If Cin is 1, the output of NAND gate 522 will be 0. If Cin is 0, the output of NAND gate 522 will be 1. In other words, NAND gate 522 inverts the value of Cin. Since, when Sel is equal to 0, the output of NAND gate 521 is always 1, the corresponding input to NAND gate 523 will always be 1 if Sel is 0. The output of NAND gate 523 (hence multiplexer 520) therefore depends upon the output of NAND gate 522. When the output of NAND gate 522 is 1, the output of NAND gate 523 is 0. When the output of NAND gate 522 is 0, the output of NAND gate 523 is 1. NAND gate 523 therefore inverts the output of NAND gate 522. Ultimately, when Sel is 0, the output of multiplexer 520 (MUXout) is equal to Cin. As noted above, the entire circuit illustrated in FIG. 5, including XOR gate 510 and multiplexer 520 implements the truth table shown in FIG. 4. It can be seen from the first three columns of the table in this figure that XOR gate 510 operates in the normal manner, generating an output signal (XORout) that is 1 if only one of the inputs is a 1, and 0 otherwise. Multiplexer 520 also operates in the normal manner, producing a MUXout signal that is equal to XORout if the select signal, Sel, is 1 and is equal to Cin if Sel is 0. Thus, in the combined operation of XOR gate 510 and multiplexer 520, when Sel is 1 (so that XORout is selected and Cin is deselected), the output signal (MUXout) is dependent only upon XORout. It does not matter what the value of Cin is in this instance. Consequently, the value of Cin in the truth table is shown as “*” where Sel is 1. Conversely, when Sel is 0, Cin is selected and XORout is deselected. Therefore, output signal MUXout is dependent only upon Cin and the value of XORout is irrelevant. This is of interest because, when Cin is selected and XORout is deselected, XOR gate 510 continues to operate normally, generating a signal (XORout) corresponding to the received input signals (Ain and Bin) and drawing power in the process. In particular, the structure of XOR gate 510 is such that there are spikes in the power drawn by the gate when there are transitions in XORout. In other words, when XORout transitions from 0 to 1, or from 1 to 0, there is a power spike. Since the value of XORout is irrelevant to the output of the combined circuit, however, these transitions are unnecessary. By reducing or eliminating the transitions in XORout when XORout is deselected, the amount of power used by XOR gate 510 can be reduced, making the circuit more efficient. The various embodiments of the invention take advantage of the fact that it is not necessary to maintain normal operation of the deselected gate or to expend to the power that would be necessary for normal operation. Thus, the operation of the gate is modified to reduce the number of signal transitions when the output of the gate is deselected. It should be noted that, while the specific embodiments described herein focus on the combination of an XOR gate with a multiplexer, alternative embodiments may incorporate gates other than XOR gates. For example, the circuit may be a combination of a multiplexer with an AND gate, an OR gate, or some other type of gate. In some embodiments, multiple gates may be employed in place of the single XOR gate described in the examples herein. Referring now to FIG. 6, a diagram illustrating the electrical components of a modified XOR-multiplexer combinational logic circuit in accordance with one embodiment is shown. This circuit includes a group of components forming a modified XOR gate 610, a group of components forming a modified multiplexer 620, and a group of components 630 used to generate signals B and B_b from input signal Bin. The circuit illustrated in FIG. 6 has inputs and outputs that are identical to the circuit of FIG. 5 and operates according to a truth table for which the values of these inputs and outputs are identical to the values shown in FIG. 4. The truth table for the circuit of FIG. 6 is a shown in FIG. 7. The only difference between the truth tables of FIG. 4 and FIG. 7 is the values of the intermediate signal, XORout, when Sel has a value of 1. In the circuit of FIG. 6, input signal Bin, rather than simply being inverted to generate B_b and then inverted again to generate B is processed by circuit 630. In circuit 630, Bin and Sel are input to a NAND gate 631, the output of which is used as B_b. B_b is then inverted by inverter 632 to generate B. B_b and B are then used in the circuit formed by modified XOR gate 610 and modified multiplexer 620. Modified XOR gate 610 is, in this embodiment, actually an XNOR gate. In gate 610 may therefore be alternately referred to as an XNOR gate, or a modified XOR gate. XNOR gate 610 consists of a NAND gate 611 and six transistors 612-617. Three of the transistors, 612, 614 and 615 are PMOS transistors, while the other three transistors, 613, 616 and 617, are NMOS transistors. Input signals Ain and Sel are provided to NAND gate 611. The output of NAND gate 611 is coupled to the output of modified XOR gate 610 through transistors 612 and 613. If one of transistors 612 or 613 is turned on, the output of NAND gate 611 is effectively directly coupled to the output of modified XOR gate 610. If both of transistors 612 and 613 are turned off, the output of NAND gate 611 is isolated from the output of modified XOR gate 610. Transistors 612 and 613 are turned on by signals B and B_b, respectively. If the output of NAND gate 611 is isolated from the output of modified XOR gate 610, the output of modified XOR gate 610 is controlled by transistors 614-617. Depending upon whether these transistors are turned on or off, and which of the transistors are turned on or off, the output of modified XOR gate 610 may be coupled either to Vcc, or to ground. If both of transistors 614 and 615 are turned on, the output of modified XOR gate 610 will be coupled to Vcc, and the output of the gate will be 1. If both of transistors 616 and 617 are turned on, the output of modified XOR gate 610 will be coupled to ground and the output of the gate will be 0. The output of modified XOR gate 610 is input to multiplexer 620. Rather than being input to a NAND gate as in FIG. 5, the output of modified XOR gate 610 is directly input to NAND gate 622. The other input to NAND gate 622 is provided by NAND gate 621. The inputs to NAND gate 621 include the signals Cin and Sel_b. The output of NAND gate 622 is the output of multiplexer 620 (MUXout). As noted above, the circuit of FIG. 6 implements the truth table of FIG. 7. This circuit operates as follows. In order to select the XOR gate as the output of the multiplexer, the select signal, Sel, is set to 1 (and Sel_b is 0). Referring to multiplexer 620, the inputs to NAND gate 621 are Sel_b (0) and Cin. Regardless of the value of Cin, the output of NAND gate 621 will be 1 (because input Sel_b is 0). Consequently, the corresponding input to NAND gate 622 will be 1, and the output of NAND gate 622 will depend upon the output of modified XOR gate 610. More specifically, the output of NAND gate 622 will be the inverse of the output of modified XOR gate 610. Therefore, in order to operate as a combination of an XOR gate and a multiplexer, modified XOR gate 610 must provide at its output the inverse of a normal XOR gate output (i.e., the output of an XNOR gate) when Sel is 1. First, it should be noted that, referring to circuit 630, if Sel is 1, B is equal to Bin, and B_b is equal to the inverse of Bin. Thus, if Bin is 1, B is 1 and B_b is 0. Conversely, if Bin is 0, B is 0 and B_b is 1. Referring then to modified XOR gate 610, if Sel is 1, the output of NAND gate 611 is the inverse of Ain. Assuming both Ain and Bin are 0, a 0 is applied to transistor 612 and a 1 is applied to transistor 613, turning both of these transistors on. The output of NAND gate 611 (a 1) is therefore coupled to the output of modified XOR gate 610. It should be noted that is are applied to transistors 614 and 615, turning both of them off and isolating the output of modified XOR gate 610 from Vcc. A 1 is applied to transistor 616, turning it on and a 0 is applied to transistor 617, turning it off. The output of modified XOR gate 610 is therefore also isolated from ground. Therefore, for Ain and Bin equal to 0, the output of modified XOR gate 610 is 1. Assuming that both Ain and Bin are 1 (and Sel is 1), the output of NAND gate 611 is 0. A 1 is applied to transistor 612, and a 0 is applied to transistors 613, turning both of these transistors off. The output of modified XOR gate 610 is therefore isolated from the output of NAND gate 611. 0s are applied to transistors 614 and 615, turning both of these transistors on. The output of modified XOR gate 610 is thereby coupled to Vcc (logic 1). A 0 is applied to transistor 616, turning it off, and a 1 is applied to transistor 617, turning it on. Because transistor 616 is turned off, the output of modified XOR gate 610 is isolated from ground. Thus, for Ain and Bin equal to 0, the output of modified XOR gate 610 is 1. If Ain is 0 and Bin is 1 (and Sel is 1), the output of NAND gate 611 is 1. A 1 is applied to transistor 612 and a 0 is applied to transistor 613, turning both of these transistors off. The output of modified XOR gate 610 is thereby isolated from the output of NAND gate 611. A 0 is applied to transistor 614 and a 1 is applied to transistor 615, turning them both off. Because transistors 614 and 615 are turned off, the output of modified XOR gate 610 is isolated from Vcc. 1s are applied to both transistor 616 and transistor 617, turning both of these transistors on. Because both of transistors 616 and 617 are turned on, the output of modified XOR gate 610 is coupled to ground (logic 0). Consequently, for Ain equal to 0 and Bin equal to 1, the output of modified XOR gate 610 is 0. If Ain is 1 and Bin is 0 (and Sel is 1), the output of NAND gate 611 is 0. A 0 is applied to transistor 612 and a 1 is applied to transistor 613, turning both of these transistors on. The output of modified XOR gate 610 is thereby coupled to the output of NAND gate 611. A 1 is applied to transistor 614, turning it off, and a 0 is applied to transistor 615, turning it on. Because transistor 614 is turned off, the output of modified XOR gate 610 is isolated from Vcc. 0s are applied to those transistor 616 and transistor 617, turning both of these transistors off and isolating the output of modified XOR gate 610 from ground. As result, for Ain equal to 1 and Bin equal to 0, the output of modified XOR gate 610 is 0. It is therefore apparent that, when Sel is 1 and the output of modified XOR gate 610 is selected, the output of multiplexer 620 is that of an XOR gate. As mentioned above, when Sel is 0 and the output of modified XOR gate 610 is deselected, it does not matter whether modified XOR gate 610 provides the same outputs, as they will be disregarded by multiplexer 620. Modified XOR gate 610 is therefore designed to eliminate transitions between output values of 0 and 1 and to thereby eliminate the power drain associated with these transitions. More specifically, modified XOR gate 610 is designed to provide an output value of 1 whenever Sel is 0 in order to insure that the output of multiplexer 620 is equal to Cin. The operation of the circuit of FIG. 6 will be described below for the situation in which Sel is 0. First, referring to multiplexer 620, if Sel is 0, Cin should be selected and the output of modified XOR gate 610 should be deselected. When Sel is 0, Sel_b is 1, and the corresponding input to NAND gate 621 will be 1, as long as Cin is selected. Since the Sel_b input to NAND gate 621 is one, the output of NAND gate 621 will be the inverse of the other input, Cin. As long as the output of modified XOR gate 610 is 1, NAND gate 622 will serve to invert the output of NAND gate 621, and Cin will be provided at the output of multiplexer 620. It will therefore be shown below that, when Sel is 0 (Cin is selected and the output of modified XOR gate 610 is deselected), the output of modified XOR gate 610 will always be 1. Referring to circuit 630, when Sel is 0, the output of NAND gate 631 will always be 1. Consequently, B_b will be 1 and B will be 0, regardless of the value of Bin. Similarly, because the Sel input to NAND gate 611 in 0, the output of NAND gate 611 will be 1, regardless of the value of Ain. Consequently, for any values of Ain and Bin, the operation of modified XOR gate 610 will be as follows. A 0 is applied to transistor 612 and a 1 is applied to transistor 613, turning both of these transistors on. The output of NAND gate 611 (logic one) is therefore directly coupled to the output of modified XOR gate 610. 1s are applied to both of transistors 614 and 615, turning both of these transistors off and isolating the output of modified XOR gate 610 from Vcc. A 1 is applied to transistor 616, turning it on, and a 0 is applied to transistor 617, turning it off. Because transistor 617 is turned off, the output of modified XOR gate 610 is isolated from ground. Thus, a can be seen that, when Cin is selected (Sel is 0 and Sel_b is 1), the output of modified XOR gate 610 is 1, regardless of the values of Ain and Bin. The embodiment of FIG. 6 provides a number of advantages over conventional designs. One of these advantages is the fact that, when the output of modified XOR gate 610 is deselected, the voltages applied to the gates of transistors 612-617 remain constant, and these voltages are such that the output of modified XOR gate 610 is isolated from both Vcc and ground. The design of modified XOR gate 610 therefore eliminates data transitions and the corresponding spikes in the amount of power that is used by the circuit. (It should be noted that alternative embodiments may reduce the number of data transitions rather than entirely eliminating them.) Another advantage provided by the design illustrated in FIG. 6 is that one of the gates that is normally used in the conventional design (NAND gate 221 in FIG. 5) is eliminated. This simplifies the design and eliminates power requirements and that were associated with the eliminated gate. Still other advantages may be apparent to those of skill in the art. It should be noted that there are various circuit-level designs for XOR gates and multiplexers, and that other embodiments may vary from the specific design of the circuit illustrated in FIG. 6. Several examples of these alternative embodiments that operate as a combined XOR gate and multiplexer are described below. Further, as noted above, alternative embodiments of the invention are not limited to simple XOR-multiplexer combinations. For example, one alternative embodiment may comprise an XOR gate coupled to an n-input multiplexer rather than a simple 2-input multiplexer as shown above. Another alternative embodiment may comprise an n-input XOR gate coupled to a multiplexer. Still another alternative embodiment may comprise an entirely different type of gate, or combination of gates coupled to a multiplexer. In each of these embodiments, the logic gate(s) are designed to operate in one mode (corresponding to normal operation) when selected by the multiplexer and to operate in a different mode when deselected. In the embodiments described above, the second mode may, in part, be characterized as a power saving noted in which the number of data transitions is reduced or eliminated in order to avoid power drains corresponding to the data transitions. As mentioned above, the circuit-level design of a logic gate (e.g., an XOR gate) may vary in different embodiments, while still performing an identical function. Different circuit-level designs may provide different advantages. This is true for conventional designs, as well as different embodiments of the invention. For example, referring to FIG. 8, an alternative conventional design for a combination of an XOR gate and a multiplexer is shown. The prior art circuit design of FIG. 8 performs the same logic function as the prior art circuit of FIG. 5, but has a different implementation. It should be noted that the embodiment of the invention which is illustrated in FIG. 6 uses a number of circuit elements that are similar to the prior art circuit of FIG. 5. Therefore, the embodiment illustrated in FIG. 6 may be considered to be based, to some extent, upon the conventional design of FIG. 5. Likewise, the embodiment of the invention illustrated in FIG. 9 may be considered to be based, to some extent, upon the conventional design of FIG. 8. Referring to FIG. 10, a diagram illustrating a circuit in accordance with an alternative embodiment of the invention is shown. The circuit of FIG. 10 comprises a modified XOR gate coupled to a multiplexer. FIG. 10 also includes a truth table corresponding to the circuit in the figure. Referring to FIG. 11, a diagram illustrating a circuit in accordance with another alternative embodiment of the invention is shown. The circuit of FIG. 11 comprises a modified XOR gate coupled to a multiplexer. FIG. 11 also includes a truth table corresponding to the circuit in the figure. Referring to FIG. 12, a diagram illustrating a circuit in accordance with yet another alternative embodiment of the invention is shown. The circuit of FIG. 12 comprises a modified XOR gate coupled to a multiplexer. FIG. 12 also includes a truth table corresponding to the circuit in the figure. Referring to FIG. 13, a diagram illustrating a circuit in accordance with still another alternative embodiment of the invention is shown. The circuit of FIG. 13 comprises a modified XOR gate coupled to a multiplexer. FIG. 13 also includes a truth table corresponding to the circuit in the figure. Referring to FIG. 14, a diagram illustrating a circuit in accordance with yet another alternative embodiment of the invention is shown. The circuit of FIG. 14 comprises a modified XOR gate coupled to a multiplexer. FIG. 14 also includes a truth table corresponding to the circuit in the figure. Referring to FIG. 15, a diagram illustrating a circuit in accordance with another alternative embodiment of the invention is shown. The circuit of FIG. 15 comprises a modified XOR gate coupled to a multiplexer. The multiplexer in this embodiment comprises a four-way multiplexer. FIG. 15 also includes a truth table corresponding to the circuit in the figure. Those of skill in the art will understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof. The information and signals may be communicated between components of the disclosed systems using any suitable transport media, including wires, metallic traces, vias, optical fibers, and the like. While it is anticipated that the embodiments specifically described herein will be implemented in a computer microprocessor, the various illustrative logical blocks, modules, and circuits described in connection with the embodiments disclosed herein may be implemented in a variety of ways, for example, some embodiments may eb implemented in application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), digital signal processors (DSPs) or other logic devices, discrete gates or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. The benefits and advantages which may be provided by the present invention have been described above with regard to specific embodiments. These benefits and advantages, and any elements or limitations that may cause them to occur or to become more pronounced are not to be construed as critical, required, or essential features of any or all of the claims. As used herein, the terms “comprises,” “comprising,” or any other variations thereof, are intended to be interpreted as non-exclusively including the elements or limitations which follow those terms. Accordingly, a system, method, or other embodiment that comprises a set of elements is not limited to only those elements, and may include other elements not expressly listed or inherent to the claimed embodiment. | <SOH> BACKGROUND OF THE INVENTION <EOH>Digital logic circuits are widely used in electronic systems. These systems may be very simple systems, such as individual logic gates that are used for simple control circuits. They may also include moderately complex systems, such as integrated logic circuits that are used for controllers are embedded processors. These systems may also include processors that are much more complex and are used in powerful computing systems. These digital electronic systems are typically designed primarily in terms of the logic functions that are performed by their various subsystems and components. In other words, the design of the system focuses on the logic that will be used by the system to handle input, output, control and other information. The logic design is based upon the use of logic gates, such as AND, OR, NAND, NOR, XOR and various other types of gates. While these gates are, from the perspective of the logic design, the basic building blocks of the hardware logic of the system, it is important to keep in mind that each of these gates typically comprises transistors and various other electronic components that are combined to form the logic gate. The electronic components that form the gates of the digital logic require power to operate. In other words, the logic gates are not simply passive devices that require no power to produce a desired output from a given input. Because of the increasing number of logic gates and corresponding electronic components in systems such as data processors, the amount of power that is required by the electronic components is increasingly a concern in the design of these systems. Accordingly, it is, as a general matter, always desirable to provide new ways to reduce the amount of power that is required by the system. Even a small power savings at the electronic component (sub-gate) level may translate to a large power savings at the system level because of the large number of electronic components within the system. | <SOH> SUMMARY OF THE INVENTION <EOH>One or more of the problems outlined above may be solved by the various embodiments of the invention. Broadly speaking, the invention comprises systems and methods for reducing the power consumption of some combinations of logic gates by reducing the number of unnecessary transitions that are made by logic gates that do not affect the output of the logic. One embodiment of the invention comprises a system including a first logic circuit configured to receive one or more logic circuit input signals and to generate a logic circuit output signal; and a multiplexer configured to receive the logic circuit output signal and one or more additional signals as multiplexer input signals. The multiplexer is configured to also receive a select signal that controls the multiplexer to select one of the multiplexer input signals to be provided as a multiplexer output signal. When the select signal controls the multiplexer to select the logic circuit output signal as the multiplexer output signal, the first circuit operates in a first mode, and when the select signal controls the multiplexer to deselect the logic circuit output signal as the multiplexer output signal, the first circuit operates in a second mode. In one embodiment, the first logic circuit is a modified XOR gate and the second mode is a power saving mode in which the data transitions in the output of the XOR gate are eliminated to reduce the power used by the XOR gate. An alternative embodiment of the invention comprises a method including the steps of providing a first logic circuit configured to receive one or more logic circuit input signals and to generate a logic circuit output signal, providing a multiplexer configured to receive the logic circuit output signal and one or more additional signals as multiplexer input signals and to receive a select signal that controls the multiplexer to select one of the multiplexer input signals to be provided as a multiplexer output signal. The method further includes operating the first logic circuit in a first mode when the first logic circuit is selected by the multiplexer and operating the first logic circuit in a second mode when the first logic circuit is deselected by the multiplexer. In one embodiment, the first logic circuit is a modified XOR gate and the second mode is a power saving mode in which the data transitions in the output of the XOR gate are eliminated to reduce the power used by the XOR gate. Numerous additional embodiments are also possible. | 20040123 | 20060418 | 20050728 | 75175.0 | 0 | CHANG, DANIEL D | SYSTEMS AND METHODS FOR OPERATING LOGIC CIRCUITS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,764,192 | ACCEPTED | System and method for wellbore clearing | In accordance with one embodiment, a method is provided for clearing the inside of a wellbore including inserting a wellbore clearing system into the wellbore. The wellbore clearing system includes an anchor adapted to be positioned within the wellbore, an agitator operable to be moved relative to the interior surface of the wellbore, and a linkage coupling the agitator to the anchor. The method further includes securing the anchor within the wellbore and moving the agitator relative to the interior surface of the wellbore. The movement of the agitator is operable to at least partially eliminate a restriction to a flow of minerals or other resources in the wellbore. | 1. A system for clearing the inside of a wellbore, comprising: an anchor adapted to be positioned within the wellbore; an agitator coupled to the anchor, the agitator operable to move relative to the interior surface of the wellbore, the movement of the agitator operable to at least partially eliminate a restriction to a flow of minerals or other resources in the wellbore; a linkage adapted to couple the agitator to the anchor; and a drive mechanism coupled to the agitator and operable move the agitator relative to the interior surface of the wellbore. 2. The system of claim 1, wherein movement of the agitator operable to at least partially eliminate a restriction to a flow of minerals or other resources in the wellbore comprises moving the agitator to mix fines contained within the wellbore with fluid contained in the wellbore to facilitate removal of the fines from the wellbore. 3. The system of claim 2, wherein the agitator comprises a plurality of extensions operable to facilitate mixing the fines with the fluid contained in the wellbore. 4. The system of claim 1, wherein movement of the agitator operable to at least partially eliminate a restriction to a flow of minerals or other resources in the wellbore comprises moving the agitator to facilitate movement of solids within the wellbore. 5. The system of claim 4, wherein the agitator comprises a plurality of extensions operable to facilitate moving the solids contained in the wellbore. 6. The system of claim 1, wherein the agitator comprises: one or more agitator portions; and one or more expansion joints coupling the agitator portions and operable to allow relative independent movement of each agitator portion. 7. The system of claim 1, wherein the wellbore comprises an articulated wellbore. 8. The system of claim 1, wherein the wellbore comprises a pipe. 9. The system of claim 1, wherein the anchor is positioned in the wellbore using a workstring adapted to be removably coupled to the anchor. 10. The system of claim 1, wherein the agitator is selected from the group consisting of a belt, a wire, a cable, a chain, a corkscrew-shaped rod, a corkscrew-shaped tube, a helical-shaped rod, and a helical-shaped tube. 11. The system of claim 1, wherein the linkage comprises a pulley operable to rotate in response to movement of the agitator. 12. The system of claim 1, wherein the linkage comprises a spring coupled to the anchor, the spring adapted to facilitate longitudinal motion of the agitator relative to the surface of the wellbore. 13. The system of claim 1, wherein the linkage comprises a joint operable to rotate relative to the anchor, the joint operable to facilitate the rotation of the agitator in the wellbore. 14. The system of claim 1, wherein the anchor is secured within the wellbore using teeth coupled to the anchor, the teeth adapted to be extended from the anchor to engage the interior surface of the wellbore. 15. The system of claim 1, wherein the anchor is secured within the wellbore by inflating the anchor to fill at least a portion of the wellbore. 16. The system of claim 1, wherein the drive mechanism comprises a hand-operated crank. 17. The system of claim 1, wherein the drive mechanism comprises a motor. 18. The system of claim 1, wherein the drive mechanism is operable to rotate the agitator relative to the interior surface of the wellbore. 19. The system of claim 1, wherein the drive mechanism is operable to move the agitator longitudinally relative to the interior surface of the wellbore. 20. A method for clearing the inside of a wellbore, comprising: inserting a wellbore clearing system into the wellbore, the wellbore clearing system comprising an anchor adapted to be positioned within the wellbore, an agitator operable to be moved relative to the interior surface of the wellbore, and a linkage coupling the agitator to the anchor; securing the anchor within the wellbore; and moving the agitator relative to the interior surface of the wellbore, the movement of the agitator operable to at least partially eliminate a restriction to a flow of minerals or other resources in the wellbore. 21. The method of claim 20, wherein moving the agitator to at least partially eliminate a restriction to a flow of minerals or other resources in the wellbore comprises moving the agitator to mix fines contained within the wellbore with fluid contained in the wellbore to facilitate removal of the fines from the wellbore. 22. The method of claim 21, wherein the agitator comprises a plurality of extensions operable to facilitate mixing the fines with the fluid contained in the wellbore. 23. The method of claim 21, further comprising removing the fluid/fine mixture from the wellbore. 24. The method of claim 23, wherein the fluid/fine mixture is removed from the wellbore through fluid flow of the fluid mixed with the fines from a subterranean zone. 25. The method of claim 23, wherein the fluid/fine mixture is removed from the wellbore through the pumping of water mixed with the fines from a subterranean zone. 26. The method of claim 20, wherein moving the agitator to at least partially eliminate a restriction to a flow of minerals or other resources in the wellbore comprises moving the agitator to facilitate movement of solids within the wellbore. 27. The method of claim 26, wherein the agitator comprises a plurality of extensions operable to facilitate movement of the solids contained in the wellbore. 28. The method of claim 20, wherein the agitator comprises: one or more agitator portions; and one or more expansion joints coupling the agitator portions and operable to allow relative independent movement of each agitator portion. 29. The method of claim 20, further comprising: removably coupling a workstring to the anchor; and positioning the anchor within the wellbore using the workstring. 30. The method of claim 29, further comprising disengaging the workstring from the anchor once the anchor is secured within the wellbore and removing the workstring from the wellbore. 31. The method of claim 29, further comprising re-coupling the workstring to the anchor and removing the anchor and agitator from the wellbore. 32. The method of claim 20, wherein the wellbore comprises an articulated wellbore. 33. The method of claim 20, wherein the wellbore comprises a pipe. 34. The method of claim 20, wherein securing the anchor within the wellbore comprises extending teeth from the body of the anchor, the teeth adapted to engage the interior surface of the wellbore. 35. The method of claim 20, wherein securing the anchor within the wellbore comprises inflating the anchor to fill at least a portion of the wellbore. 36. The method of claim 20, wherein the agitator is selected from the group consisting of a belt, a wire, a cable, a chain, a corkscrew-shaped rod, a corkscrew-shaped tube, a helical-shaped rod, and a helical-shaped tube. 37. The method of claim 20, wherein the linkage comprises a spring coupled to the anchor, the spring adapted to facilitate longitudinal motion of the agitator relative to the surface of the wellbore. 38. The method of claim 20, wherein the linkage comprises a joint operable to rotate relative to the anchor, the joint operable to facilitate the rotation of the agitator in the wellbore. 39. The method of claim 20, wherein the linkage comprises a pulley adapted to rotate in response to movement of the agitator. 40. The method of claim 20, wherein the agitator is moved using a drive mechanism. 41. The method of claim 40, wherein the drive mechanism comprises a hand-operated crank. 42. The method of claim 40, wherein the drive mechanism comprises a motor. 43. The method of claim 40, wherein the drive mechanism is operable to rotate the agitator relative to the interior surface of the wellbore. 44. The method of claim 40, wherein the drive mechanism is operable to move the agitator longitudinally relative to the interior surface of the wellbore. 45. A system for clearing the inside of a wellbore, comprising: a first means operable to move relative to the interior surface of the wellbore, the movement of the first means operable to at least partially eliminate a restriction to a flow of minerals or other resources in the wellbore; a second means operable to anchor the first means within the wellbore, the second means coupled to the first means; a third means operable to couple the first means to the second means, the third means adapted to allow the first means to be moved relative to the interior surface of the wellbore; and a fourth means operable to move the first means relative to the interior surface of the wellbore, the fourth means coupled to the first means. 46. A system for clearing the inside of an articulated wellbore of a dual-well system, comprising: an anchor adapted to be positioned within the wellbore, the anchor comprising teeth adapted to be extended from the anchor to engage the interior surface of the wellbore to secure the anchor within the wellbore; an agitator coupled to the anchor, the agitator operable to be moved relative to the interior surface of the wellbore, the movement of the agitator operable to at least partially eliminate a restriction to a flow of minerals or other resources in the wellbore; a linkage adapted to couple the agitator to the anchor and to allow the agitator to move relative to the interior surface of the wellbore; and a drive mechanism coupled to the agitator and operable move the agitator relative to the interior surface of the wellbore. | TECHNICAL FIELD OF THE INVENTION The present invention relates generally to systems and methods for the recovery of subterranean resources and, more particularly, to a system and method for wellbore clearing. BACKGROUND OF THE INVENTION Subterranean drilling and production of minerals and fluids may produce substantial quantities of debris within wellbores. For example, small particles of minerals, sometimes called “fines,” can accumulate and disrupt the process of extracting minerals and other resources from the wellbores. Furthermore, solids may be present within a wellbore, which may at least partially restrict the flow of minerals and other resources within the wellbore. As a result of the buildup of fines within wellbores and the potential for solids to at least partially restrict the flow of minerals and other resources within a wellbore, techniques are need to remove fines from the wellbores and move solids within the wellbores to at least partially eliminate any flow restrictions in the wellbore. SUMMARY OF THE INVENTION The present invention provides a system and method for wellbore clearing that substantially eliminates or reduces at least some of the disadvantages and problems associated with conventional systems and methods for clearing wellbores. In accordance with certain embodiments, a system for clearing the inside of a wellbore includes an anchor adapted to be positioned within the wellbore and an agitator coupled to the anchor. The agitator is operable to move relative to the interior surface of the wellbore, the movement of the agitator operable to at least partially eliminate a restriction to a flow of minerals or other resources in the wellbore. The system further includes a linkage adapted to couple the agitator to the anchor and a drive mechanism coupled to the agitator and operable move the agitator relative to the interior surface of the wellbore. In accordance with other embodiments, a method is provided for clearing the inside of a wellbore including inserting a wellbore clearing system into the wellbore. The wellbore clearing system includes an anchor adapted to be positioned within the wellbore, an agitator operable to be moved relative to the interior surface of the wellbore, and a linkage coupling the agitator to the anchor. The method further includes securing the anchor within the wellbore and moving the agitator relative to the interior surface of the wellbore. The movement of the agitator is operable to at least partially eliminate a restriction to a flow of minerals or other resources in the wellbore. Technical advantages of particular embodiments of the present invention include a system and method that facilitate the removal of fines located on or near the bottom of a wellbore that may otherwise be difficult to remove. Another technical advantage of one embodiment of the present invention includes a system and method for moving solids in the flow path of a wellbore, so as to at least partially eliminate flow restrictions in the wellbore. Yet another technical advantage of particular embodiments of the present invention includes a system for clearing the inside of a wellbore whose components are sufficiently durable and reliable to be placed in the wellbore for extended periods of time without the need to be removed for repair or replacement. Still another technical advantage of particular embodiments of the present invention includes a system and method that can be utilized to clear pipes, conduit, tubing, or the like. Other technical advantages will be readily apparent to one skilled in the art from the figures, descriptions, and claims included herein. Moreover, while specific advantages have been enumerated above, various embodiments may include all, some, or none of the enumerated advantages. BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of particular embodiments of the invention and their advantages, reference is now made to the following descriptions, taken in conjunction with the accompanying drawings, in which: FIG. 1 illustrates an example system for wellbore clearing; FIG. 2 illustrates the wellbore clearing system of FIG. 1 after installation of the system is completed; FIG. 3 illustrates a detailed view of an example expansion joint; FIGS. 4A through 4C illustrate detailed views of example agitators and linkages of an example wellbore clearing system; and FIG. 5 is a flow chart illustrating an example method for wellbore clearing. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 illustrates an example wellbore clearing system 10 for removing “fines” 100 from a well or pipe system, such as dual-well system 12. In a certain embodiment, dual-well system 12 includes a substantially vertical wellbore 20 and an articulated wellbore 30 where each wellbore extends from surface 5 to penetrate subterranean zone 15. However, system 10 may be used in vertical wells, slant wells, or any other types of wells or well systems. Furthermore, system 10 may be used for clearing the inside of any suitable pipes, conduits, tubing, or the like. Use of the term “wellbore” is meant to include these alternatives. Subterranean zone 15 may comprise an oil or gas reservoir, a coal seam, or any other appropriate subterranean zone. Subterranean zone 15 may be accessed to remove and/or produce water, hydrocarbons, and other fluids in subterranean zone 15 or to treat minerals in subterranean zone 15 prior to mining operations. In certain embodiments, a wellbore, such as articulated wellbore 30, may contain fluids and fines as a result of the drilling process and the movement of mineral resources from subterranean zone 15 into wellbore 30. For example, when drilling into a coal seam, coal fines may be produced. Furthermore, coal fines are produced from the coal seam as fluids and gases are removed from the coal seam. System 10 is used to remove these coal fines from wellbore 30. In other embodiments, system 10 may be used to facilitate the movement of solids which may be substantially larger than fines 100, such as pieces of subterranean zone 15 which may fall into wellbore 30 as a result of a wellbore failure and restrict the flow of minerals or other resources in wellbore 30, to at least partially eliminate any restriction in the flow of minerals or other resources in wellbore 30. System 10 includes a workstring 40, an anchor 50, a linkage 60, an agitator 70, and a drive mechanism 90. In a particular embodiment, anchor 50 is temporarily coupled to workstring 40 so that workstring 40 may be used to position anchor 50 within a wellbore, such as articulated wellbore 30. Once anchor 50 is positioned, workstring 40 may be disengaged from anchor 50 and removed from wellbore 30. In other embodiments, workstring 40 may remain in place and act as an anchor for a pulley, such as the pulley of linkage 160 described below, or as a guide tube or conduit for and advancing or retreating agitator, such as agitators 170 and 370 described below. Linkage 60, discussed in more detail with reference to FIGS. 3A through 3C, couples agitator 70 to anchor 50. Anchor 50 may be any device operable to “anchor” linkage 60 and agitator 70 within wellbore 30, such as a bridge plug or other suitable restraining device. In a certain embodiment, agitator 70 runs from linkage 60, coupled to anchor 50, through wellbore 30, and up to surface 5 where it may be coupled to a manual or automatic drive mechanism 90. Movement of agitator 70 relative to a wellbore surface 32 disrupts fines 100, which may be disposed on or near a surface 32 of wellbore 30. This disruption facilitates the “mixing” of fines 100 with the fluid contained in wellbore 30, thereby allowing fines 100 to be removed from wellbore 30 with the fluid. In other embodiments, movement of agitator 70 relative to wellbore surface 32 may facilitate the movement of solids which may be substantially larger than fines 100, such as pieces of subterranean zone 15 which may fall into wellbore 30 as a result of a wellbore failure and restrict the flow of minerals or other resources in wellbore 30, to at least partially eliminate any restriction in the flow of minerals or other resources in wellbore 30. FIG. 2 illustrates wellbore clearing system 10 of FIG. 1 after installation of system 10 is completed. As described above, in a certain embodiment, anchor 50 may be positioned within wellbore 30 using workstring 40. In FIG. 2, anchor 50 has been positioned within wellbore 30 using workstring 40 and workstring 40 has been disengaged from anchor 50 and removed from wellbore 30. In a particular embodiment, anchor 50 may be secured within wellbore 30 using teeth 52 that may extend from anchor 50 once it has been positioned within wellbore 30. In this particular embodiment, anchor 50 is referred to as a “bridge plug.” Teeth 52 may be extended from anchor 50 to engage surface 32 of wellbore 30 once anchor 50 is positioned in wellbore 30. Teeth 52 may be retracted into the body of anchor 50 when anchor 50 is being positioned in wellbore 30 or when anchor 50 is being removed from wellbore 30. Teeth 52 are shown in a retracted position in FIG. 1, where anchor 50 is being positioned in wellbore 30 using workstring 40. Although teeth 52 are illustrated, any other suitable mechanism for securing anchor 50, and thereby anchoring agitator 70 within wellbore 30, may be used. For example, anchor 50 may comprise an inflatable “bladder” that is inserted into wellbore 30 in an un-inflated or under-inflated state and then inflated to secure anchor 50 within wellbore 30. Referring still to FIG. 2, agitator 70 is coupled to anchor 50 via linkage 60. Agitator 70 runs up through wellbore 30 and out through surface 5 to a drive mechanism 90. Drive mechanism 90 provides the motive force for the movement of agitator 70 within wellbore 30. Drive mechanism 90 may comprise a hand-operated crank, a motor, or any other device operable to move agitator 70 relative to the interior surface 32 of wellbore 30. The movement of agitator 70 with respect to surface 32 of wellbore 30 causes fines 100 to mix with fluid contained within wellbore 30. To facilitate this mixing, in certain embodiments agitator 70 comprises extensions 72 which further disturb the fluid and fines in wellbore 30, thereby facilitating mixing. In other embodiments, movement of agitator 70 relative to wellbore surface 32 may facilitate the movement of solids which may be substantially larger than fines 100, such as pieces of subterranean zone 15 which may fall into wellbore 30 as a result of a wellbore failure and restrict the flow of minerals or other resources in wellbore 30, to at least partially eliminate any restriction in the flow of minerals or other resources in wellbore 30. In certain embodiments, agitator 70 may include expansion joints 74, illustrated in FIG. 3, used to couple portions 78 of agitator 70 in order to allow one or more portions 78 to move independently of other portions 78 to prevent agitator 70 from becoming “jammed” in the event of a wellbore failure. Expansion joints 74 may be made from any appropriate expandable/contractible material, such as a spring 75, which can expand or contract in response to movement of agitator 70. Expansion joint 74 may also include a protective sleeve 76 to prevent the expandable/contractible material, such as spring 75, from becoming clogged by debris, such as fines or solids, within wellbore 30. Referring again to FIG. 2, the movement of agitator 70 may cause different portions 78 to move relative to each other. For example, the movement of agitator 70 may be restricted due to a wellbore collapse where debris falls on and around agitator 70. The total weight of this debris over the length of agitator 70 may prevent agitator 70 from being easily moved. However, the weight of the debris which falls on each portion 78 may be small enough that each portion 78 may be moved independently of each other portion 78 due to the coupling of portions 78 with expansion joints 76. In this situation, for example, portion 78a, closest to surface 5, may be easier to move than the remaining portions 78 of agitator 70. Therefore, portion 78a can be moved first to move any debris which has fallen on or around portion 78a. Once the debris is moved from portion 78a, portion 78b may become easier to move since less total debris weight is on or around agitator 70. Similarly, once the debris is moved on or around portion 78b, portion 78c may become easier to move. In this manner, each remaining portion 78 may be moved to move debris, such that the movement of successively more portions 78 of agitator 70, as they progress further into wellbore 30, becomes less restricted, thereby helping to clear the obstructions, such as those caused by a wellbore 30 collapse, that may cause agitator 70 to “jam” within wellbore 30. Example configurations of agitator 70, expansion joints 74, linkage 60, and extensions 72 are discussed in more detail with reference to FIGS. 4A through 4C. In certain embodiments, anchor 50, linkage 60, and agitator 70 may be disposed within wellbore 30, or any other type of wellbore, for use over an extended period of time. As such, these components may be constructed of sufficiently durable and reliable materials, including, but not limited to, wire rope or chains, so that they may be disposed within wellbore 30 for use over an extended period of time without the need to be removed from wellbore 30 for repair or replacement during that time. Anchor 50, linkage 60, and agitator 70 may also be designed and constructed to withstand the corrosive effects of the minerals and fluids that may collect in wellbore 30. FIGS. 4A through 4C illustrate alternative embodiments of anchor 50, linkage 60, and agitator 70. FIG. 4A illustrates the mixing of fines 100 with fluid contained in wellbore 30. In one example embodiment, agitator 170 may comprise a wire, cable, belt, chain, or the like coupled between drive mechanism 90 and linkage 160. Linkage 160 may comprise a pulley, which may rotate in response to “conveyor-like” movement of agitator 170 along its longitudinal axis 166. For example, the “advancing” portion 170b of agitator 170 may move in longitudinal direction 166b, while the “retreating” portion 170a of agitator 170 may move in the opposite longitudinal direction 166a as agitator 170 rotates around the pulley of linkage 160. In certain embodiments, workstring 40 may remain in place after anchor 150 is secured in wellbore 30 and act as an anchor for the pulley of linkage 160 and/or a guide tube or conduit for agitator 170. Similar to the discussion above, fines 100 are disrupted through the movement of agitator 170 relative to wellbore surfaces 32. Extensions 172 facilitate the disruption of fines 100 such that fines 100 mix with fluid contained within wellbore 30. Extensions 172 may comprise raised “nubs,” teeth, paddles, or any other suitable protrusions from agitator 170. In other embodiments, movement of agitator 170 relative to wellbore surface 32 may facilitate the movement of solids which may be substantially larger than fines 100, such as pieces of subterranean zone 15 which may fall into wellbore 30 as a result of a wellbore failure and restrict the flow of minerals or other resources in wellbore 30, to at least partially eliminate any restriction in the flow of minerals or other resources in wellbore 30. In certain embodiments, similar to the discussion above with respect to FIGS. 2-3, agitator 170 may include expansion joints 174 used to couple portions 178 of agitator 170 in order to allow one or more portions 178 to move independently of other portions 178 to prevent agitator 170 from becoming “jammed” in the event of a wellbore 30 failure. The structure and function of expansion joints 174 may be substantially similar to the structure and function of expansion joints 74 of FIG. 3. Similar to the discussion above, each portion 178 may be moved independently to move debris, such that the movement of successively more portions 78 of agitator 70, as they progress further into wellbore 30, becomes unrestricted, thereby helping to clear the obstructions, such as due to a wellbore 30 collapse, that may cause agitator 170 to “jam” within wellbore 30. The structure and functionality of anchor 150 and teeth 152 can be substantially similar to the structure and functionality of anchor 50 and teeth 52 of FIGS. 1 and 2. Although teeth 152 are illustrated, any other suitable mechanism for securing anchor 150, and thereby anchoring agitator 170 within wellbore 30, may be used. For example, anchor 150 may comprise an inflatable “bladder” that is inserted into wellbore 30 in an un-inflated or under-inflated state and then inflated to secure anchor 150 within wellbore 30. FIG. 4B illustrates the mixing of fines 100 with fluid contained in wellbore 30. In another example embodiment, agitator 270 may comprise a corkscrew- or helical-shaped tube or rod. In a particular embodiment, extensions 272 may be coupled to the corkscrew- or helical-shaped tube or rod to further facilitate mixing fines 100 with fluid contained in wellbore 30. In other embodiments, movement of agitator 270 relative to wellbore surface 32 may facilitate the movement of solids which may be substantially larger than fines 100, such as pieces of subterranean zone 15 which may fall into wellbore 30 as a result of a wellbore failure and restrict the flow of minerals or other resources in wellbore 30, to at least partially eliminate any restriction in the flow of minerals or other resources in wellbore 30. Coupler 260 may comprise a joint, such as a universal joint or a bearing, to facilitate the rotation of agitator 270 along its longitudinal axis 266. Drive mechanism 90 is coupled to agitator 270 and provides the rotational force which rotates agitator 270 to facilitate mixing fines 100 and fluid contained within wellbore 30, or moving large obstructions to prevent the wellbore flow path from being blocked, as described above. The structure and functionality of anchor 250 and teeth 252 can be substantially similar to the structure and functionality of anchor 50 and teeth 52 of FIGS. 1 and 2. Although teeth 252 are illustrated, any other suitable mechanism for securing anchor 250, and thereby anchoring agitator 270 within wellbore 30, may be used. For example, anchor 50 may comprise an inflatable “bladder” that is inserted into wellbore 30 in an un-inflated or under-inflated state and then inflated to secure anchor 250 within wellbore 30. In certain embodiments, securing anchor 250 within wellbore 30 is optional. FIG. 4C illustrates the mixing of fines 100 with fluid contained in wellbore 30. In another embodiment, agitator 370 may comprise a wire, cable, or the like coupled to drive mechanism 90. Linkage 360 may comprise a spring 375, similar to spring 75 of FIG. 3, coupled to anchor 350 and agitator 370. Linkage 360 may be covered in a protective covering 376, similar to protective covering 76 of FIG. 3, to prevent spring 375 from becoming clogged by debris, such as fines or solids, within wellbore 30. Drive mechanism 90 may be configured to move agitator 370 along its longitudinal axis 366, with the motion being assisted by the use of the spring comprising linkage 360. In a certain embodiment, agitator 370 may move in a “back-and-forth” motion along longitudinal axis 366. When the movement of agitator 370 is “retreating” in longitudinal direction 366a, spring 375 of linkage 360 may be extended with the spring force resulting from the extension assisting the “advancing” motion of agitator 370 in the opposite longitudinal direction 366b. In certain embodiments, workstring 40 may remain in place after anchor 350 is secured in wellbore 30 and act as a guide tube or conduit for an agitator 370. Similar to the alternative configurations of agitator 370 discussed above, in the present embodiment, agitator 370 may comprise extensions 372 which facilitate the mixing of fines 100 with the fluid contained in wellbore 30. In other embodiments, movement of agitator 370 relative to wellbore surface 32 may facilitate the movement of solids which may be substantially larger than fines 100, such as pieces of subterranean zone 15 which may fall into wellbore 30 as a result of a wellbore failure and restrict the flow of minerals or other resources in wellbore 30, to at least partially eliminate any restriction in the flow of minerals or other resources in wellbore 30. In certain embodiments, similar to the discussion above with respect to FIGS. 2-3, agitator 370 may include expansion joints 374 used to couple portions 378 of agitator 370 in order to allow one or more portions 378 to move independently of other portions 378 to prevent agitator 370 from becoming “jammed” in the event of a wellbore 30 failure. The structure and function of expansion joints 374 may be substantially similar to the structure and function of expansion joints 74 and 174 of FIGS. 3 and 4A, respectively. Similar to the discussion above, each portion 378 may be moved independently to move debris, such that the movement of successively more portions 378 of agitator 370, as they progress further into wellbore 30, becomes unrestricted, thereby helping to clear the obstructions, such as due to a wellbore 30 collapse, that may cause agitator 370 to “jam” within wellbore 30. The structure and functionality of anchor 350 and teeth 352 can be substantially similar to the structure and functionality of anchor 50 and teeth 52 of FIGS. 1 and 2. Although teeth 352 are illustrated, any other suitable mechanism for securing anchor 350, and thereby anchoring agitator 370 within wellbore 30, may be used. For example, anchor 350 may comprise an inflatable “bladder” that is inserted into wellbore 30 in an uninflated or under-inflated state and then inflated to secure anchor 350 within wellbore 30. Although example anchors are described, any other suitable mechanism for anchoring linkages and agitators, such as those illustrated in FIGS. 1, 2, and 4, within a wellbore may be implemented. In addition, although example linkages are described, any other suitable mechanism for coupling agitators to anchors, such as those illustrated in FIGS. 1, 2, and 4, may be implemented. Furthermore, although example agitators are described, any other suitable mechanism for agitating fines to facilitate mixing with the wellbore fluid or moving solids in wellbore 30 may be implemented to at least partially eliminate any restrictions in the flow of minerals or other resources. FIG. 5 illustrates an example method for wellbore clearing using a wellbore clearing system, such as system 10. The example method begins at step 400 where a wellbore clearing system, such as those described with reference to FIGS. 1 and 2, is inserted into wellbore 30. The wellbore clearing system may comprise an anchor, an agitator, and a linkage. At step 402, the anchor is secured within wellbore 30. In general, the anchor is positioned beyond the portion of wellbore 30 that is to be “cleared” using an agitator. At step 404, the agitator is moved relative to surface 32 of wellbore 30, thereby facilitating the mixing of fines 100 with the fluid contained in wellbore 30, or in other embodiments, moving solids which may at least partially restrict the flow of minerals or other resources in wellbore 30. At step 406, the fluid and fine mixture and/or the solids are removed from wellbore 30. The removal of the fluid/fine mixture may be accomplished through the fluid flow of the water and/or gas mixed with fines 100 from the subterranean zone. In certain embodiments, the fluid/fine mixture may be removed through the pumping of water mixed with fines 100 from the subterranean zone. Although an example method is illustrated, the present invention contemplates two or more steps taking place substantially simultaneously or in a different order. In addition, the present invention contemplates using methods with additional steps, fewer steps, or different steps, so long as the steps remain appropriate for using a wellbore clearing system, such as system 10, for removing fines or clearing obstructions from a well system, such as system 12. Furthermore, although the present invention has been described with several embodiments, a multitude of changes, substitutions, variations, alterations, and modifications may be suggested to one skilled in the art, and it is intended that the invention encompass all such changes, substitutions, variations, alterations, and modifications as fall within the spirit and scope of the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>Subterranean drilling and production of minerals and fluids may produce substantial quantities of debris within wellbores. For example, small particles of minerals, sometimes called “fines,” can accumulate and disrupt the process of extracting minerals and other resources from the wellbores. Furthermore, solids may be present within a wellbore, which may at least partially restrict the flow of minerals and other resources within the wellbore. As a result of the buildup of fines within wellbores and the potential for solids to at least partially restrict the flow of minerals and other resources within a wellbore, techniques are need to remove fines from the wellbores and move solids within the wellbores to at least partially eliminate any flow restrictions in the wellbore. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention provides a system and method for wellbore clearing that substantially eliminates or reduces at least some of the disadvantages and problems associated with conventional systems and methods for clearing wellbores. In accordance with certain embodiments, a system for clearing the inside of a wellbore includes an anchor adapted to be positioned within the wellbore and an agitator coupled to the anchor. The agitator is operable to move relative to the interior surface of the wellbore, the movement of the agitator operable to at least partially eliminate a restriction to a flow of minerals or other resources in the wellbore. The system further includes a linkage adapted to couple the agitator to the anchor and a drive mechanism coupled to the agitator and operable move the agitator relative to the interior surface of the wellbore. In accordance with other embodiments, a method is provided for clearing the inside of a wellbore including inserting a wellbore clearing system into the wellbore. The wellbore clearing system includes an anchor adapted to be positioned within the wellbore, an agitator operable to be moved relative to the interior surface of the wellbore, and a linkage coupling the agitator to the anchor. The method further includes securing the anchor within the wellbore and moving the agitator relative to the interior surface of the wellbore. The movement of the agitator is operable to at least partially eliminate a restriction to a flow of minerals or other resources in the wellbore. Technical advantages of particular embodiments of the present invention include a system and method that facilitate the removal of fines located on or near the bottom of a wellbore that may otherwise be difficult to remove. Another technical advantage of one embodiment of the present invention includes a system and method for moving solids in the flow path of a wellbore, so as to at least partially eliminate flow restrictions in the wellbore. Yet another technical advantage of particular embodiments of the present invention includes a system for clearing the inside of a wellbore whose components are sufficiently durable and reliable to be placed in the wellbore for extended periods of time without the need to be removed for repair or replacement. Still another technical advantage of particular embodiments of the present invention includes a system and method that can be utilized to clear pipes, conduit, tubing, or the like. Other technical advantages will be readily apparent to one skilled in the art from the figures, descriptions, and claims included herein. Moreover, while specific advantages have been enumerated above, various embodiments may include all, some, or none of the enumerated advantages. | 20040123 | 20060808 | 20050728 | 66434.0 | 0 | NEUDER, WILLIAM P | SYSTEM AND METHOD FOR WELLBORE CLEARING | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,764,435 | ACCEPTED | Confining positive and negative ions with fast oscillating electric potentials | Methods and apparatus for trapping or guiding ions. Ions are introduced into an ion trap or ion guide. The ion trap or ion guide includes a first set of electrodes and a second set of electrodes. The first set of electrodes defines a first portion of an ion channel to trap or guide the introduced ions. Periodic voltages are applied to electrodes in the first set of electrodes to generate a first oscillating electric potential that radially confines the ions in the ion channel, and periodic voltages are applied to electrodes in the second set of electrodes to generate a second oscillating electric potential that axially confines the ions in the ion channel. | 1. A method of trapping or guiding ions, comprising: introducing ions into an ion trap or ion guide, the ion trap or ion guide including a first set of electrodes and a second set of electrodes, the first set of electrodes defining a first portion of an ion channel to trap or guide the introduced ions; applying periodic voltages to electrodes in the first set of electrodes to generate a first oscillating electric potential that radially confines the ions in the ion channel; and applying periodic voltages to electrodes in the second set of electrodes to generate a second oscillating electric potential that axially confines the ions in the ion channel. 2. The method of claim 1, wherein: introducing ions includes introducing positive ions and negative ions into the ion trap or ion guide. 3. The method of claim 2, wherein the ion trap or ion guide includes a first end and a second end, and the positive and negative ions are introduced at the first end and the second end, respectively. 4. The method of claim 2, wherein the ion trap or ion guide includes two or more sections, the method further comprising: applying one or more DC biases to one or more of the sections of the ion trap or ion guide to confine the positive or the negative ions into one or more sections. 5. The method of claim 1, wherein: applying periodic voltages to electrodes in the first set of electrodes includes applying periodic voltages with a first frequency; and applying periodic voltages to electrodes in the second set of electrodes includes applying periodic voltages with a second frequency that is different from the first frequency. 6. The method of claim 5, wherein the first and second frequencies have a ratio that is about an integer number or a ratio of integer numbers. 7. The method of claim 6, wherein the first and second frequencies have a ratio of about two. 8. (canceled) 9. The method of claim 7, wherein the ion channel has an axis, and the first oscillating electric potential defines substantially zero electric field at the axis of the ion channel, and the second oscillating electric potential defines substantially non-zero electric field at the axis of the ion channel. 10. The method of claim 7, wherein the first oscillating potential includes an oscillating quadrupole, hexapole or larger multipole potential. 11. The method of claim 7, wherein the second oscillating potential includes an oscillating dipole potential. 12. The method of claim 1, wherein: the first and second oscillating electric potentials define a pseudopotential for each particular mass and charge of the introduced ions such that each of the defined pseudopotentials specifies a corresponding potential barrier along the ion channel. 13. The method of claim 1, wherein: the first set of electrodes includes a plurality of rod electrodes. 14. The method of claim 1, wherein: the second set of electrodes includes a plurality of rod electrodes defining a second portion of the ion channel. 15. The method of claim 1, wherein: the second set of electrodes includes one or more plate ion lens electrodes. 16. The method of claim 15, wherein: the second set of electrodes includes a first plate ion lens electrode at a first end of the ion channel and a second plate ion lens electrode at a second end of the ion channel. 17. An apparatus, comprising: a first set and a second set of electrodes, the first set of electrodes arranged to define a first portion of an ion channel to trap or guide ions; and a controller configured to apply periodic voltages to electrodes in the first set and the second set to establish a first oscillating electric potential and a second oscillating electric potential, wherein the first and second oscillating electric potentials have different spatial distributions and confine ions in the ion channel in radial and axial directions, respectively. 18. The apparatus of claim 17, wherein positive and negative ions are mixed in the ion channel, and the controller is configured to cause simultaneous confinement of the positive and negative ions in the ion channel in both radial and axial directions. 19. The apparatus of claim 17, wherein the controller is configured to: apply periodic voltages to electrodes in the first set of electrodes with a first frequency; and apply periodic voltages to electrodes in the second set of electrodes with a second frequency that is different from the first frequency. 20. The apparatus of claim 19, wherein the first and second frequencies have a ratio that is about an integer number or a ratio of integer numbers. 21. The apparatus of claim 17, wherein the first set of electrodes includes a plurality of rod electrodes. 22. The apparatus of claim 17, wherein the second set of electrodes includes a plurality of rod electrodes defining a second portion of the ion channel. 23. The apparatus of claim 17, wherein the second set of electrodes includes one or more plate ion lens electrodes. 24. The apparatus of claim 23, wherein the second set of electrodes includes a first plate ion lens electrode at a first end of the ion channel and a second plate ion lens electrode at a second end of the ion channel. 25. The method of claim 5, wherein: introducing ions includes introducing positive ions and negative ions into the ion trap or ion guide. 26. The method of claim 25, wherein the ion trap or ion guide includes a first end and a second end, and the positive and negative ions are introduced at the first end and the second end, respectively. 27. The method of claim 25, wherein the ion trap or ion guide includes two or more sections, the method further comprising: applying one or more DC biases to one or more of the sections of the ion trap or ion guide to confine the positive or the negative ions into one or more sections. 28. The method of claim 5, wherein the voltages applied to the first and second sets of electrodes are out of phase relative to one another. | BACKGROUND The present invention relates to mass spectrometry. A mass spectrometer analyzes masses of sample particles, such as atoms and molecules, and typically includes an ion source, one or more mass analyzers and one or more detectors. In the ion source, the sample particles are ionized. The sample particles can be ionized with a variety of techniques that use, for example, chemical reactions, electrostatic forces, laser beams, electron beams or other particle beams. The ions are transported to one or more mass analyzers that separate the ions based on their mass-to-charge ratios. The separation can be temporal, e.g., in a time-of-flight analyzer, spatial e.g., in a magnetic sector analyzer, or in a frequency space, e.g., in ion cyclotron resonance (“ICR”) cells. The ions can also be separated according to their stability in a multipole ion trap or ion guide. The separated ions are detected by one or more detectors that provide data to construct a mass spectrum of the sample particles. In the mass spectrometer, ions are guided, trapped or analyzed using magnetic fields or electric potentials, or a combination of magnetic fields and electric potentials. For example, magnetic fields are used in ICR cells, and multipole electric potentials are used in multipole traps such as three-dimensional (“3D”) quadrupole ion traps or two-dimensional (“2D”) quadrupole traps. For example, linear 2D multipole traps can include multipole electrode assemblies, such as quadrupole, hexapole, octapole or greater electrode assemblies that include four, six, eight or more rod electrodes, respectively. The rod electrodes are arranged in the assembly about an axis to define a channel in which the ions are confined in radial directions by a 2D multipole potential that is generated by applying radio frequency (“RF”) voltages to the rod electrodes. The ions are traditionally confined axially, in the direction of the channel's axis, by DC biases applied to the rod electrodes or other electrodes such as plate lens electrodes in the trap. In a portion of the channel defined by the rod electrodes, the DC biases can generate electrostatic potentials that axially confine either positive ions or negative ions, but cannot simultaneously confine both. Additional AC voltages can be applied to the rod electrodes to excite, eject, or activate some of the trapped ions. In MS/MS experiments, selected precursor ions (also called parent ions) are first isolated or selected, and next reacted or activated to induce fragmentation to produce product ions (also called daughter ions). Mass spectra of the product ions can be measured to determine structural components of the precursor ions. Typically, the precursor ions are fragmented by collision activated dissociation (“CAD”) in which the precursor ions are kinetically excited by electric fields in an ion trap that also includes a low pressure inert gas. The excited precursor ions collide with molecules of the inert gas and may fragment into product ions due to the collisions. Product ions can also be produced by electron capture dissociation (“ECD”) or ion-ion interactions. In ECD, low energy electrons are captured by multiply charged positive precursor ions, which then may undergo fragmentation due to the electron capture. To induce ECD processes in ICR cells, the precursor ions and the electrons are radially confined by large magnetic fields, typically from about three to about nine Tesla. Axially, the positive precursor ions and the electrons are confined by electrostatic potentials in adjacent regions. Near the border of the adjacent regions, trajectories of the precursor ions and the electrons may overlap and ECD may take place. Alternatively, the trapped precursor ions may be exposed to a flux of low energy electrons. Multipole ion traps typically use RF multipole potentials to radially confine ions. An electron's mass-to-charge ratio is one hundred thousand to one million times smaller than mass-to-charge ratios of typical precursor ions. Conventional multipole traps, however, can simultaneously confine only particles whose mass-to-charge ratios do not differ more than about a few hundred times. It has been suggested that ECD can be performed in a multipole trap if additional magnetic fields are used to trap the electrons or a large flux of electrons is introduced. Ion-ion interactions have been used to generate product ions in 3D quadrupole traps, where an oscillating 3D quadrupole potential can simultaneously confine positive and negative ions in a central volume, and no electrostatic potentials are required to provide axial confinement. SUMMARY In a 2D multipole ion trap or ion guide that defines an internal volume, ions are confined by oscillating electric potentials in both radial and axial directions. In general, in one aspect, the invention provides techniques for trapping or guiding ions. Ions are introduced into an ion trap or ion guide. The ion trap or ion guide includes a first set of electrodes and a second set of electrodes. The first set of electrodes defines a first portion of an ion channel to trap or guide the introduced ions. Periodic voltages are applied to electrodes in the first set of electrodes to generate a first oscillating electric potential that radially confines the ions in the ion channel, and periodic voltages are applied to electrodes in the second set of electrodes to generate a second oscillating electric potential that axially confines the ions in the ion channel. Particular implementations can include one or more of the following features. Introducing ions can include introducing positive ions and negative ions into the ion trap or ion guide. The ion trap or ion guide can include a first end and a second end, and the positive and negative ions can be introduced at the first end and the second end, respectively. The ion trap or ion guide can include two or more sections, and one or more DC biases can be applied to one or more of the sections of the ion trap or ion guide to confine the positive or the negative ions into one or more sections. Applying periodic voltages to electrodes in the first set of electrodes can include applying periodic voltages with a first frequency, and applying periodic voltages to electrodes in the second set of electrodes can include applying periodic voltages with a second frequency that is different from the first frequency. The first and second frequencies can have a ratio that is about an integer number or a ratio of integer numbers. The first and second frequencies have a ratio of about two. The first and second oscillating electric potentials can have different spatial distributions. The ion channel can have an axis, and the first oscillating electric potential can define substantially zero electric field at the axis of the ion channel, and the second oscillating electric potential can define substantially non-zero electric field at the axis of the ion channel. The first oscillating potential can includes an oscillating quadrupole, hexapole or larger multipole potential. The second oscillating potential can include an oscillating dipole potential. The first and second oscillating electric potentials can define a pseudopotential for each particular mass and charge of the introduced ions such that each of the defined pseudopotentials specifies a corresponding potential barrier along the ion channel. The first set of electrodes can include a plurality of rod electrodes. The second set of electrodes can include a plurality of rod electrodes defining a second portion of the ion channel. The second set of electrodes can include one or more plate ion lens electrodes. The second set of electrodes can include a first plate ion lens electrode at a first end of the ion channel and a second plate ion lens electrode at a second end of the ion channel. In general, in another aspect, the invention provides an apparatus. The apparatus includes a first set and a second set of electrodes and a controller. The first set of electrodes is arranged to define a first portion of an ion channel to trap or guide ions. The controller is configured to apply periodic voltages to electrodes in the first set and the second set to establish a first oscillating electric potential and a second oscillating electric potential, wherein the first and second oscillating electric potentials have different spatial distributions and confine ions in the ion channel in radial and axial directions, respectively. Particular implementations can include one or more of the following features. The controller can be configured to confine simultaneously positive and negative ions in the ion channel in both radial and axial directions. The controller can be configured to apply periodic voltages to electrodes in the first set of electrodes with a first frequency, and to electrodes in the second set of electrodes with a second frequency that is different from the first frequency. The first and second frequencies can have a ratio that is about an integer number or a ratio of integer numbers. The first set of electrodes can include a plurality of rod electrodes. The second set of electrodes can include a plurality of rod electrodes defining a second portion of the ion channel, or one or more plate ion lens electrodes. The second set of electrodes can include a first plate ion lens electrode at a first end of the ion channel and a second plate ion lens electrode at a second end of the ion channel. The invention can be implemented to provide one or more of the following advantages. Positive and negative ions can be simultaneously confined in an internal volume defined by electrode structures in a 2D multipole ion trap. Due to the simultaneous confinement in the same volume, product ions can be generated by ion-ion interactions. The 2D multipole ion trap can trap substantially more (typically, thirty to one hundred fold more) positive and negative ions than a 3D quadrupole trap. Thus, the 2D multipole trap can provide more product ions for a later analysis, which can be performed with larger signal-to-noise ratios, and low abundance product ions may also be detected. The positive and negative ions can be more conveniently introduced in a 2D multipole ion trap than into a 3D quadrupole trap. For example, the positive ions can be introduced at one end of a linear 2D multipole trap and the negative ions can be introduced at the other end. The positive ions can be precursor ions and the negative ions can be reagent ions that may induce charge transfer to or from the precursor ions. Alternatively, the positive ions can be reagent ions and the negative ions can be precursor ions. Alternatively, negative reagent ions may abstract charged species, typically one or more protons, from the precursor ion. The charge transfer can reduce a multiple charge of the precursor ion, invert the charge polarity of the precursor ion, or induce a fragmentation of the precursor ion. For precursor ions such as phosphopeptide ions, the charge transfer reaction may precipitate fragmentation that results in product ion spectra that are more informative than the product ion spectra of the same species produced with CAD alone. Such charge transfer may induce fragmentation or simply charge reduction of ions other than the precursor ions, such as fragmentation or charge reduction of the product ions produced by prior charge transfer reactions. In a linear 2D quadrupole trap or other 2D multipole rod assembly, precursor ions and reagent ions having opposite sign of charge can be trapped in the same volume both radially and axially by a superposition of RF electric potentials, without large magnetic fields. A segmented linear trap can initially store precursor ions and reagent ions in separate segments and induce fragmentation later by allowing the precursor ions and the reagent ions to interact in the same segment or segments. Before allowing their interaction, the precursor ions or the reagent ions may be manipulated in the separate segments using conventional methods, such as selecting the precursor or reagent ions by established methods of isolation. The ion-ion interactions can be stopped at any time by re-segregating the positive and negative ion populations. In a channel where an ion population includes positive ions, negative ions or both, and the ions are radially confined by electric fields defined by a primary RF potential, a secondary RF electric potential can define electric fields that selectively confine ions of the population in the axial direction of the channel based on the mass and charge of an ion, but independent of the sign of the ion's charge. Thus, axial confinement can be used as a valve or a gate that can be opened or closed to allow or block the passage of ions in the axial direction. Axial confinement can be provided by an electric potential that is generated by secondary RF voltages applied to lens end plate electrodes. In an assembly with two or more axial segments, the ions can be axially confined by applying different combination of RF voltages to multipole rods in different segments of the assembly. One or more of the segments of the assembly, can be implemented by separate 2D multipole traps. Axial confinement may also be achieved by applying secondary RF voltages to auxiliary electrodes located around, adjacent or in between the multipole rod electrodes of the multipole ion trap. Because linear ion traps are readily adapted to other mass spectrometers, after performing ion-ion reaction experiments in the linear ion traps, the product ions can be easily transported for analysis to different mass analyzers, such as TOF, FTICR or different RF ion trap mass spectrometers. Thus ion-ion experiments can use a wide range of instruments, not just 3D quadrupole ion traps. The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Unless otherwise noted, the verbs “include” and “comprise” are used in an open-ended sense—that is, to indicate that the “included” or “comprised” subject matter is a part or component of a larger aggregate or group, without excluding the presence of other parts or components of the aggregate or group. The terms “front”, “center”, and “back,” are used to denote parts of an apparatus, such as a multipole ion trap or equivalent thereof, in schematic illustrations without particular reference to the actual locations of the parts of the apparatus in any absolute sense, such as when the apparatus is inverted or rotated. Other features and advantages of the invention will become apparent from the description, the drawings and the claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram illustrating apparatus for mass spectrometry according to one aspect of the invention. FIGS. 2A-2D are schematic diagrams illustrating axial confinement of ions with oscillating electric potentials. FIG. 3 is a schematic flow diagram illustrating a method for mass spectrometry according to one aspect of the invention. FIG. 4 is a schematic flow diagram illustrating a method for inducing ion-ion reactions. FIGS. 5A-5F are schematic diagrams illustrating an exemplary implementation of inducing ion-ion reactions in a segmented multipole trap. FIG. 6 is a schematic diagram illustrating an alternative embodiment of apparatus to induce ion-ion interactions. FIG. 7 is a schematic diagram illustrating yet another alternative embodiment of apparatus to induce ion-ion interactions. DETAILED DESCRIPTION FIG. 1 illustrates a mass spectrometry system 100 configured to operate according to one aspect of the invention. The system 100 includes a precursor ion supplier 110, a 2D multipole ion trap 120, a reagent ion supplier 130 and a controller 140. The precursor ion supplier 110 generates ions that include precursor ions. The ions generated by the precursor ion supplier 110 are injected into the 2D multipole ion trap 120. The reagent ion supplier 130 generates ions that include reagent ions. The ions generated by the reagent ion supplier 130 are also injected into the 2D multipole ion trap 120. The 2D multipole ion trap 120 defines a channel in which the precursor ions and the reagent ions can be confined both radially and axially by oscillating electric potentials generated by periodic voltages that are applied to different electrodes in the ion trap 120 by the controller 140. The precursor ion supplier 110 includes one or more precursor ion sources 112 to generate precursor ions from sample molecules, such as large biological molecules, and ion transfer optics 115 to guide the generated ions from the precursor ion sources 112 to the ion trap 120. Precursor ions can be generated using electrospray ionization (“ESI”), thermospray ionization, field, plasma or laser desorption, chemical ionization or any other technique to generate precursor ions. The precursor ions can be positive or negative ions and can have single or multiple charges. For example, ESI techniques produce multiply charged ions from large molecules that have multiple ionizable sites. The reagent ion supplier 130 includes one or more reagent ion sources 132 to generate reagent ions from sample molecules, and ion transfer optics 135 to guide the generated ions from the reagent ion sources 132 to the ion trap 120. Upon interaction, the reagent ions may induce charge transfer from the reagent ions to other ions, such as the precursor ions generated by the precursor ion supplier 110. The reagent ions can induce proton transfer or electron transfer to or from the precursor ions. For positive precursor ions, the reagent ions can include anions derived from perfluorodimethylcyclohexane (PDCH) or SF6. For negative precursor ions, the reagent ions can be positive ions, such as Xenon ions. The choice of the particular reagent ions can depend on the precursor ions and/or parameters of the ion trap. For positive precursor ions, the reagent ion sources 132 generate negative reagent ions using chemical ionization, ESI, thermospray, particle bombardment, field, plasma or laser desorption. For example in chemical ionization, negative reagent ions are generated by associative or dissociative processes in a chemical plasma that includes neutral, positively and negatively charged particles, such as ions or electrons. In the chemical plasma, low energy electrons may be captured by neutral particles to form a negative ion. The negative ion may be stable or may fragment into product ions that include negative ions. The negative reagent ions can be extracted from the chemical plasma, for example, by electrostatic fields. In alternative implementations, the reagent ion sources 132 generate the reagent ions using other techniques. For example, positive and negative ions can be generated by ESI, and the negative reagent ions can be selected using electrostatic fields. The ion transfer optics 115 and 135 transport the ions generated by the precursor ion sources 112 and the reagent sources 132, respectively, to the multipole ion trap 120. The ion transfer optics 115 or 135 can include one or more 2D multipole rod assemblies such as quadrupole or octapole rod assemblies to confine the transported ions radially in a channel. The ions can be transported between different rod assemblies by inter-multipole lenses. The ion transfer optics 115 or 135 can be configured to transport only positive or negative ions or to select ions with particular ranges of mass-to-charge ratios. The ion transfer optics 115 or 135 can include lenses, ion tunnels, plates or rods to accelerate or decelerate the transported ions. Optionally, the ion transfer optics 115 or 135 can include ion traps to temporarily store the transported ions. The multipole ion trap 120 includes a front plate lens 121, a back plate lens 128 and two or more sections between the lenses 121 and 128. In the implementation shown in FIG. 1, the ion trap 120 includes a front section 123, a center section 125 and a back section 127. The front lens 121 defines a front aperture 122 to receive the ions transported by the ion transfer optics 115 from the precursor ion sources 112, and the back lens 128 defines a back aperture 129 to receive the ions transported by the ion transfer optics 135 from the reagent ion sources 132. Each of the sections 123, 125 and 127 includes a corresponding 2D multipole rod assembly, such as a quadrupole rod assembly including four quadrupole rod electrodes. Each of the multipole rod assemblies defines a portion of a channel about an axis 124 of the ion trap 120. In this channel, ions can be radially and axially confined in one or more of the sections 123, 125, 127 by oscillating electric potentials generated by the voltages applied to the multipole rod electrodes and the lenses 121 and 128 of the ion trap 120. In alternative implementations, one or more of the sections 123, 125 and 127 can be implemented by separate 2D ion traps. The controller 140 applies a corresponding set of RF voltages 143, 145 and 147 to multipole rod assemblies in the sections 123, 125 and 127, respectively, to generate oscillating 2D multipole potentials that confine ions in radial directions in the channel about the axis 124. In one implementation, the controller 140 applies a primary set of RF voltages to each of the rod assemblies in the sections 123, 125 and 127. For quadrupole assemblies with two pairs of opposing rods, the primary set of RF voltages can include a first RF voltage for the first pair of opposing rods, and a second RF voltage with the same RF frequency and opposite phase for the second pair of opposing rods. Alternatively, the controller 140 can apply RF voltages 143, 145 and 147 with different frequencies or phases to multipole rod assemblies in different sections of the ion trap. The controller 140 can also apply RF voltages 141 and 148 to the front lens 121 and the back lens 128, respectively. The RF voltages 141 and 148 can have different frequencies or phases from the frequencies or phases of the sets of RF voltages 143 and 147 applied to the rod assemblies in the front section 123 and the end section 128, respectively. The RF voltages 141 and 148 applied to the front lens 121 and the back lens 128 generate oscillating electric potentials that can simultaneously confine positive and negative ions in the axial direction at the corresponding end of the channel about the axis 124. Axially confining ions with oscillating electric potentials is further discussed below with reference to FIGS. 2A-2D. The controller 140 can apply different DC biases 151-158 to the lenses 121 and 128 and the rod assemblies in different sections of the ion trap 120. Depending on the sign of the DC bias applied in a section of the trap 120, positive or negative ions can be axially confined in that section. For example, positive precursor ions can be trapped in the front section 123 by applying a negative DC bias to the multipole rods in the front section 123 and substantially zero DC bias to the center section 125 and the front lens 121. Similarly, negative reagent ions can be trapped in the back section 127 by applying a positive DC bias to the multipole rods in the back section 127 and substantially zero DC bias to the center section 125 and the back lens 121. By applying different DC biases to different segments and lenses, the positive and negative ions can be received or separated in the ion trap 120, as discussed below with reference to FIGS. 4-5F. The controller 140 can also apply additional AC voltages to the electrodes in the ion trap to eject ions from the ion trap 120 based on the ions' mass-to-charge ratios. FIG. 2A is a schematic illustration of confining positive ions 210 and negative ions 215 simultaneously in a 2D multipole ion trap at an end section 230 that is adjacent to an ion lens 220. For example, the end section 230 can be the front section 123 or the back section 127 of the ion trap 120 and the ion lens 220 can be the front lens 121 or the back lens 128 in the system 100 (FIG. 1). The end section 230 includes a 2D multipole rod assembly 232 that receives RF voltages from an RF voltage source 240 to generate an oscillating 2D multipole potential to confine radially the positive 210 and negative 220 ions close to an axis 234 of the multipole ion trap. For example, the rod assembly 232 can be a quadrupole rod assembly that generates an oscillating 2D quadrupole potential about the axis 234. The ion lens 220 receives RF voltages from the RF voltage source 245 to generate an oscillating electric potential that axially confines both the positive 210 and the negative 215 ions. That is, the axially confining potential prevents the ions 210 and 215 from escaping the end section 230 through an aperture 225 in the ion lens 220. The axially confining potential has a different spatial distribution than the multipole potential generated by the assembly 232. The multipole potential defines substantially zero electric fields at the axis 234, and the axially confining potential defines substantially non-zero electric fields at the axis 234 near the ion lens 220. The multipole rod assembly 232 includes rod electrodes that receive RF voltages with a first frequency and the ion lens 220 receives RF voltages with a second frequency. In one implementation, the first frequency and the second frequency are related to each other by a rational number. For example, the first frequency is substantially an integer multiple or an integer fraction of the second frequency. Alternatively, the first frequency can be any other multiple or fraction of the second frequency. Or the first and second frequencies can be substantially equal, while the ion lens 220 receives an RF voltage that is out-of-phase with the RF voltages received by the rod assembly 232. Typically, the rod assembly 232 receives RF voltages with multiple phases. In a quadrupole rod assembly, neighboring rod electrodes receive voltages that are 180 degrees out of phase relative to each other. Thus, the ion lens 220 can receive an RF voltage that has about (plus or minus) ninety-degree phase difference relative to each of the voltages received by the rod electrodes in the quadrupole rod assembly. FIG. 2B shows a coordinate system 250 to schematically illustrate a trajectory 260 describing a typical movement of the positive 210 or negative 215 ions when they approach the ion lens 220. In the coordinate system 250, a vertical axis 252 represents time and a horizontal axis 255 represents a corresponding axial distance of the ions from the ion lens 220 along the axis 234. The trajectory 260 illustrates ion movements in the absence of a background gas. If background gas molecules are present, the ion trajectories become different. For example, small gas molecules may provide a damping for a large ion's movement; or the ion's trajectory may become stochastic due to random collisions between the ion and the gas molecules. The trajectory 260 includes three trajectory portions 262, 264 and 266. In the first trajectory portion 262, the ions move only in the multipole potential that radially confines the ions close to the axis 234, where the multipole potential defines substantially zero electric fields. Thus along the axis 234, the ions may move axially with a substantially uniform speed and approach the aperture 225 in the ion lens 220. The substantially uniform speed is represented in the trajectory 260 by a substantially uniform slope of the first trajectory portion 262. In the second trajectory portion 264, the ions experience electric fields that are generated by the oscillating electric potential due to the RF voltage applied to the ion lens 220. The oscillating potential defines electric fields that force the ions to oscillate according to the frequency of the applied RF voltage. These oscillations of the ions are represented by fluctuations in the second trajectory portion 264. The fluctuations can be described as fast oscillations about a center corresponding to an average location of the ion during a few oscillations. This center moves more slowly and smoothly than the ion itself, as schematically illustrated by a center trajectory 268 in FIG. 2B. The center trajectory 268 can be determined using an adiabatic approximation—a detailed description of the approximation (including limits of its applicability) can be found in “Inhomogeneous RF fields: A versatile tool for the study of processes with slow ions” by Dieter Gerlich in State-selected and stat-to-state ion-molecule reaction dynamics, Part 1. Experiment, Edited by Check-Yiu NG and Michael Baer, Advances in Chemical Physics Series, Vol. LXXXII, © 1992 John Wiley & Sons, Inc. The adiabatic approximation describes separately the fast oscillations in the second trajectory portion 264 and the much slower motion of the oscillations' center along the center trajectory 268. For a particular ion, the center trajectory 268 can be described as if the ion moved in a pseudopotential VP (which is also referred to as the effective potential or the quasipotential) that is independent of time and the sign of the charge of the ion. The pseudopotential VP, however, depends on the ion's mass m, a charge number (“Z”) that specifies the net number and sign of the ion's charge (“Q=Z e”), and characteristics of the oscillating electric potential that causes the fast oscillations. For an oscillating electric potential that generates an electric field E(r,t) oscillating with an angular frequency (“Ω”) and an amplitude E(r) at a location r as E(r,t)=E(r)cos(Ωt), the pseudopotential VP(r) is given at the location r as VP(r)=ZeE(r)2/(4m Ω2) (Eq. 1). As the ion approaches the aperture 225 along the axis 234, the lens 220 generates an increasing electric field amplitude E(r) and, according to Eq. 1, an increasing magnitude of the pseudopotential VP. The gradient of the pseudopotential points away from the lens 220 and the aperture 225 defined by the lens 220, because the sign of the pseudopotential is the same as the sign of the ion's charge. This gradient determines the direction and strength of an average force experienced by the ion. Subject to this average force, the ion turns back before reaching the aperture 225, as illustrated by the center trajectory 268. Thus in the channel about the axis 234, the ion is axially confined by the oscillating electric potential generated by the RF voltage applied to the lens 220. Because the pseudopotential VP has the same sign as the charge number Z of the ion, it can confine both the positive 210 and negative 215 ions. The pseudopotential VP depends on the mass m of the ion and the ion's charge (Q=Z e). According to this dependence, the same oscillating electric potential may confine some ions while allowing other ions to pass. FIG. 2C illustrates an example in which a smaller ion 212 and a larger ion 214 approach the ion lens 220 in the end section 230. The ions 212 and 214 have the same positive charge and similar kinetic energies, but the larger ion 214 has a larger mass than the smaller ion 212. The ions 212 and 214 are confined radially close to the axis 234 by a 2D multipole field generated by RF voltages applied to the multipole rod electrodes 232 by the RF voltage source 240. The RF voltage source 245 applies RF voltages to the ion lens 220 to generate an oscillating electric field that confines the smaller ion 212 but allows the larger ion 214 to leave the end section 230 and pass through the aperture 225 of the lens 220. FIG. 2D schematically illustrates pseudopotentials for the example shown in FIG. 2C. In a coordinate system 270, pseudopotential values are represented on a vertical axis 272, and an axial distance from the lens 220 along the axis 234 is represented on a horizontal axis 274. The represented pseudopotentials are defined by the same oscillating electric potential generated by the ion lens 220. The oscillating electric potential defines a first pseudopotential 282 for the small ion 212 and a second pseudopotential 284 for the large ion 214. Because these pseudopotentials are defined by the same oscillating electric potential, the electric field amplitude E(r) is the same for both (see Eq. 1). Thus, the first 282 and second 284 pseudopotentials have similar shapes as a function of the axial distance (“r”) from the lens 220. The pseudopotentials 282 and 284 have substantially zero values at large distances from the lens 220, and increase as the corresponding ions approach the lens 220. Each of he increasing pseudopotentials 282 and 284 defines a barrier as the maximum value of the corresponding pseudopotential along the axis 234 of the ion trap. The first pseudopotential 282 defines a first barrier 283, which is higher than a second barrier 285 defined by the second pseudopotential 284. The difference between the barriers 283 and 285 is due to the mass-to-charge difference between the smaller ion 212 the larger ion 214. For other ions with different mass and/or charge values, the pseudopotential barriers can be determined by finding the maximum value of Eq. 1 for locations along the axis 234. The smaller ion 212 and the larger ion 214 have average energy levels 292 and 294, respectively. The average energy levels can be defined by averaging the ions' energy during one period of the oscillating potential. In the example, the average energy levels 292 and 294 have similar values. For the smaller ion 212, the average energy level 292 is below the corresponding barrier 283. Accordingly, the smaller ion 212 is axially confined by the oscillating electric potential. After reaching the point where the average energy level 292 is substantially equal to the local value of the pseudopotential 282, the smaller ion 212 turns away from the lens 220. For the larger ion 214, however, the average energy level 294 is above the corresponding barrier 285. Accordingly, the larger ion 214 is not confined axially by the oscillating electric potential, and can leave the end section 230 through the aperture 225. The above described adiabatic approximation and the corresponding pseudopotentials have limits of applicability. For example, the adiabatic approximation can be used only if the electric field amplitude |E(r)| is substantially larger than its variation measured by the electric field's gradient (“∇E”) times a characteristic amplitude of the fast oscillations. That is, if the electric field changes too much between extremes of a single oscillation of an ion, the adiabatic description is invalid and the pseudopotential cannot be used to describe the ion's motion. Based on this condition, a dimensionless adiabacity parameter ζ can be defined for an ion with mass m and charge Z in an electric field oscillating with a single frequency Ω as ζ=2Z|∇E|/mΩ2. Typically, the adiabatic approximation is valid if the adiabacity parameter ζ is less than about 0.3. The adiabacity parameter ζ is inversely proportional to the mass-to-charge ratio m/Z of the ion. That is, the larger the mass-to-charge ratio of the ion, the more likely it is that the adiabatic approximation is valid. Near the axial pseudo potential barriers in a quadrupole trap, the trapped ions may experience undesired linear, non-linear, or parametric excitations, and can escape from the trap. Such excitations may be avoided if the ions are trapped with appropriately chosen RF electric fields. FIG. 3 illustrates a method 300 for performing mass analysis according to the techniques described above. The method 300 can be performed by a system including a 2D multipole ion trap in which positive and negative ions can be confined radially and axially by separate oscillating electric potentials as discussed above with reference to FIGS. 1-2D. For example, the system can include the system 100 (FIG. 1) in which an RF voltage can be applied to the front lens 121 or the back lens 128 to axially confine both positive and negative ions in the ion trap 120. Alternatively, the method 300 can be performed using segmented traps discussed below with reference to FIGS. 6 and 7. The system induces fragmentation of precursor ions into product ions by confining the precursor ions and reagent ions in the multipole ion trap radially and axially with separate oscillating electric potentials (step 310). The precursor ions can be positive ions and the reagent ions can be negative ions, or vice versa. The precursor and reagent ions are introduced in the same portion of a channel defined by the multipole ion trap, for example, as discussed below with reference to FIGS. 4-5F. In the channel, positive and negative ions are confined both radially and axially by oscillating electric potentials. Being confined in the same portion of the channel, the precursor and reagent ions interact with each other and charge may be transferred from the reagent ions to the precursor ions. The charge transfer may induce charge reduction of a multiply charged precursor ion or even a charge reversal of the precursor ions. The charge transfer may have an energy that dissociates the precursor ions into two or more fragments. Typically when CAD is used alone in ion traps, only the precursor ions are activated to fragment them into product ions, and the generated product ions are not activated to be further fragmented. In charge transfer induced reactions, however, the reagent ions may also interact with the fragments of the precursor ions to yield further fragmentation or other product. In alternative implementations, the ion-ion interactions between the precursor and reagent ions can be used for other purposes than fragmentation. For example, interaction with reagent ions can be used for charge reduction in a mixture of precursor ions that have the same mass but different multiple charged states. The charge reduction can provide a suitable number of desired charge states of the precursor ions. The reagent ions can also be used to reduce charge of multiply charged product ions generated, for example, from some highly charged precursor species. The charge reduction of the product ions can simplify the mass analysis and the interpretation of the resulting product ion mass spectrum. Instead of both positive and negative ions, only positive or only negative ions can also be radially and axially confined and manipulated in the ion trap by oscillating electric potentials. The system removes the reagent ions from the ion trap while retaining the product ions (step 320). To retain positive product ions and remove negative reagent ions, a negative DC bias can be applied to the section including the ions. When they are exposed to the negative DC bias, negative reagent ions become axially unstable, while the positive product ions become axially more stable. To retain negative product ions and remove positive reagent ions, a positive DC bias can be applied to the same section. Alternatively, the reagent ions can be removed by resonance ejection or destabilized radially in the ion trap. The system analyzes the product ions according to their mass-to-charge ratios (step 330). In one implementation, the multipole ion trap selectively ejects the product ions based on their mass-to-charge ratios. The system detects the ejected product ions using one or more particle multipliers, and determines their mass-to-charge spectra. In alternative implementations, the ejected product ions can be guided to a mass analyzer, such as a time of flight analyzer, a magnetic, electromagnetic, ICR or quadrupole ion trap analyzer or any other mass analyzer that can determine the mass-to-charge ratios of the product ions. The mass-to-charge ratios of the product ions can be used to reconstruct the structure of the precursor ions. In alternative implementations, the reagent ions, the precursor ions or the product ions can be further manipulated in the ion trap. For example before analyzing the product ions (step 330), some of the product ions may be ejected from the ion trap. FIG. 4 illustrates a method 400 for inducing fragmentation of precursor ions using reagent ions. The method 400 can be performed by a system, such as the system 100 (FIG. 1), that includes a segmented multipole ion trap with two or more sections in which multipole rods define an ion channel to trap or guide ions. The system injects and isolates precursor ions in the multipole ion trap (step 410). To isolate positive precursor ions with particular mass-to-charge ratios, positive ions are generated from a sample and injected into the ion channel of the ion trap. Next, the ion trap ejects sample ions that have mass-to charge ratios other than the mass-to-charge ratios of the chosen precursor ions using, for example, resonance ejection. Thus, only the desired precursor ions remain trapped in the ion trap. Optionally, the ion trap can receive the sample ions and eject some of the non-precursor ions simultaneously. The system moves the positive precursor ions into a first section of the multipole ion trap (step 420). To do so, the system can apply a negative DC bias to multipole rods in the first section and substantially zero or smaller negative DC biases to other sections. The system injects negative reagent ions into a second section of the multipole ion trap (step 430). The second section is different from the first section in which the positive precursor ions are trapped. The positive ions in the first section are separated from the negative ions in the second section by electrostatic potential barriers generated by negative and positive DC biases that are applied to the first and second sections, respectively. Alternatively, the first and second sections can be separated by a third section generating an oscillating electric potential that defines pseudopotentials axially confining and separating both the positive and the negative ions in the channel of the ion trap. The system allows the positive precursor ions and the negative reagent ions to move into the same section or sections of the multipole ion trap to induce fragmentation of the precursor ions (step 440). If DC biases separated the ions in the first section from the ions in the second section, the system can remove the DC biases and allow the positive and negative ions to move in both of the first and second sections. Without DC biases, the positive and negative ions can be trapped simultaneously in the ion trap by oscillating electric potentials that axially confine ions in the ion channel of the ion trap, as discussed above with reference to FIGS. 1-2D. If the first and second sections are separated by a third section in which an oscillating electric potential axially confines both the precursor and the reagent ions, the system can alter or turn off the oscillating potential such that the precursor ions, the reagent ions, or both can traverse through the third section. Being confined in the same section or sections of the ion trap, the positive precursor ions and the negative reagent ions can interact such that charge transfer and collisions may fragment the precursor ions. FIGS. 5A-5E schematically illustrate an exemplary implementation of the method 400 using negative reagent ions and axially confining oscillating potentials. In the example, a 2D multipole ion trap 500 defines an ion channel about an axis 502. The trap 500 includes a front lens 503, a front section 504, a center section 505, a back section 506, and a back lens 507. Each of the sections 504-506 includes a corresponding set of multipole rods that receive RF voltages (e.g., with a frequency of about 1.2 MHz) to generate an oscillating multipole potential that radially confines ions in the ion channel about the axis 502. In addition, the lenses 503 and 507 can also receive RF voltages to axially confine ions in the ion channel. In the ion trap 500, DC biases can be applied to any of the components 503-507. In the ion trap 500, a 0.001 torr of Helium gas provides dissipation or damping for the ions. In FIG. 5A, positive sample ions 511 are injected into the ion trap 500. The sample ions 511 include ions with different masses and single or multiple positive charges. The sample ions 511 can be generated by ESI or any other ionization technique. The sample ions are injected into the ion trap through an aperture in the front lens 503, and are accumulated in the center section 505. During injection, different DC biases are applied to different components of the ion trap 500, as illustrated by a schematic diagram 510. The front lens 503, the front section 504 and the center section 505 receive negative DC biases 513, 514 and 515, respectively. The negative biases 513, 514 and 515 have progressively larger values, such as about −3 Volts, −6 Volts and −10 Volts, respectively, to generate electrostatic fields that impel the positive sample ions 511 towards the center section 505. The back section 506 receives a positive DC bias 516, such as about +3 Volts, to generate an electrostatic field that prevents the sample ions 511 from escaping the center section through the back lens 507, which receives a substantially zero DC bias 517, e.g., having a value less than about 30 mV. FIG. 5B illustrates the isolation of precursor ions from the sample ions 511 trapped in the center section 505 of the ion trap 500. An AC voltage is applied to the multipole rods in the center section 505 in addition to the RF voltages that generate the multipole fields. The AC voltage generates electric fields that cause the trap to eject ions that have different mass-to-charge ratios than the selected precursor ions, leaving only the precursor ions in the trap 500. A schematic diagram 520 illustrates DC biases applied to different components of the trap 500 during the isolation. The front lens 503 and the back lens 507 have substantially zero DC biases 523 and 527, respectively. The center section 505 has a negative DC bias 525, such as about −10 V. The front section 504 and the back section 506 have negative DC biases 524 and 526, respectively, whose value is smaller than the bias 525 to generate electrostatic fields that axially confine the positive ions in the center section 505. FIG. 5C illustrates the movement of the precursor ions 531 from the center section 505, in which they have been isolated, to the front section 504. As illustrated by a schematic diagram 530, the center section 505 has a DC bias 535 of about −10 V. A DC bias 534 having a larger negative value than the DC bias 535 of the center section 505 is applied to the front section 504, causing the positive precursor ions 531 to move from the center section 505 into the front section 504. For example, the DC bias 534 can have a value of about −13V. Thus, an electrostatic field is generated that moves the positive precursor ions 531 from the center section 505 to the front section 504. The front lens 503 has a substantially zero DC bias 533 to generate an electrostatic field that prevents the positive precursor ions from escaping from the front section 504 through the front lens 503. The back section 506 and the back lens 507 have a negative bias 536 and a substantially zero bias 537, respectively, to generate electrostatic fields that move the positive precursor ions towards the front section 504 and prevent their escape through the back lens 507. FIG. 5D illustrates the injection of negative reagent ions 541 into the center section 505 while the positive precursor ions 531 are held in the front section 504 of the ion trap 500. The reagent ions 541 can be generated by chemical ionization or any other suitable ionization technique. The negative reagent ions are injected into the ion trap through an aperture in the back lens 507, and are accumulated in the center section 505. During injection, different DC biases are applied to different components of the ion trap 500, as illustrated by a schematic diagram 540. The back lens 507, the back section 506 and the center section 505 receive positive DC biases 547, 546 and 545, respectively. The positive biases 547, 546 and 545 have larger and larger values, such as about +1 V, +3 V and +5 V, respectively, to generate electrostatic fields that move the negative reagent ions 541 towards the center section 505. In the center section 505, the reagent ions collide with the background gas and become trapped. The front section 504 receives a negative DC bias 544, such as about −3 V, to trap the positive precursor ions 531 and separate them from the negative reagent ions 541 in the center section 505. The front lens 503 receives a positive DC bias 543, such as about 3V, to generate an electrostatic field that prevents the precursor ions 531 from escaping from the front section 504 through the aperture in the front lens 503. FIG. 5E illustrates the mixing of the positive precursor ions 531 and the negative reagent ions 541 along the axis 502 in all the sections 504, 505 and 506 of the multipole ion trap 500. As illustrated in a schematic diagram 550, each of the sections 504, 505 and 506 have substantially identical DC biases, such as a substantially zero DC bias 558, to allow the movement of the positive and negative ions along the axis 502. The same DC bias 558 is also applied to the front lens 503 and the back lens 507. Near the lenses 503 and 507, both the positive precursor ions 531 and the negative reagent ions 541 are axially confined along the axis 502 by oscillating electric potentials 553 and 557 generated by RF voltages applied to the front lens 503 and the back lens 507, respectively. For example, both the front lens 503 and the back lens 507 can receive an RF voltage with an amplitude of about 150 V and a frequency of about 600 kHz, which is about half of the RF frequency applied to the rod electrodes. Thus the precursor ions 531 and the reagent ions 541 are confined in the same volume and their interactions may induce charge transfers and fragmentations of the precursor ions. The charged fragments (i.e., the product ions) are confined axially by the same oscillating electric potentials 553 and 557 as the precursor and reagent ions. FIG. 5F illustrates the removal of the negative reagent ions 541 from the ion trap 500 while retaining the positive product ions 561. As schematically illustrated in a diagram 560, the negative reagent ions 241 can be removed from the trap 500 by applying a negative DC bias 565 to the center section 505 and substantially zero DC biases 561 and 568 to the front section 503 and the back section 506, respectively. The DC biases 561, 565 and 568 generate electric fields that allow the negative reagent ions 541 to exit towards the front lens 503 and the back lens 507, and confine the positive product ions 561 in the center section 505. To remove the reagent ions through the lenses 503 and 507, no substantial DC bias or RF field is applied to the lenses. After removing the reagent ions, the product ions can be analyzed, for example, by selectively ejecting product ions with different mass-to-charge ratios. Alternatively, the product ions can be further manipulated in the ion trap. FIG. 6 schematically illustrates an alternative embodiment in which positive and negative ions can be both radially and axially confined using oscillating electric potentials in a multipole ion trap 600. The multipole ion trap 600 includes a front section 610, a center section 620 and a back section 630 that define a channel about an axis 601. Each of the sections 610, 620 and 630 includes a multipole rod assembly, such as a quadrupole rod assembly that includes two pairs of opposing rod electrodes. Alternatively, the rod assemblies can be hexapole, octapole or larger assemblies including three, four or more pairs of opposing rod electrodes. In each of the sections 610, 620 and 630, FIG. 6 schematically illustrates one pair of opposing rod electrodes, that is, rod electrodes 612 and 614 in the front section 610, rod electrodes 622 and 624 in the center section 620, and rod electrodes 632 and 634 in the back section 630. In the center section 620, the opposing rod electrodes 622 and 624 receive RF voltages V1 in the same phase to generate, in combination with the other rod electrodes in the center section 620, an oscillating multipole potential, such as a quadrupole potential. The generated oscillating multipole potential radially confines ions close to the axis 601, where the multipole potential defines substantially zero electric fields. In the front section 610, the opposing rod electrodes 612 and 614 receive the same RF voltages V1 as the rod electrodes 622 and 624 in the center section 620 to generate, in combination with the other rod electrodes in the front section 610, an oscillating multipole potential that radially confines ions close to the axis 601. In addition to the RF voltages V1, the rod electrodes 612 and 614 also receive another RF voltage V2 that have substantially opposite phases in the opposing rod electrodes 612 and 614. Thus the rod electrodes 612 and 614 also generate an oscillating dipole potential in the front section 610. The dipole potential defines substantially non-zero electric fields at the axis 601 in the front section 610. Thus, the oscillating dipole potential can axially confine both positive and negative ions trapped in the center section 620. Other opposing rod electrodes in the front section 610 can also generate oscillating dipole potentials. For different opposing rods in the front section 610, the dipole potentials can have the same or different oscillation frequencies, and for the same frequency, can be in phase or out of phase relative to each other. In the back section 630, the opposing rod electrodes 632 and 634 receive the same RF voltages as the opposing rods 612 and 614 in the front section 610. Thus, the opposing rods 632 and 634 in the back section 630 also generate an oscillating multipole potential to confine the ions radially close to the axis 601, and an oscillating dipole potential to confine the ions axially in the center section 620. Because the oscillating electric potentials can confine both positive and negative ions, the ion trap 600 can be operated to induce ion-ion interactions and corresponding fragmentation in the center section 620. FIG. 7 schematically illustrates still another embodiment in which positive and negative ions can be both radially and axially confined using oscillating electric potentials in a multipole ion trap 700. The multipole ion trap 700 includes a front lens 703, sections 704-709, and a back lens 710. Each of the sections 704-709 includes a multipole rod assembly, such as a quadrupole or larger assembly, to trap or guide ions in an ion channel about an axis 702. The multipole ion trap 700 can be operated to separately receive a first and a second set of ions, and later induce interactions between ions of the two sets by confining them into the same section or sections of the ion trap 700. For example, the first set can include precursor ions and the second set can include reagent ions. The first set of ions can be received through the front lens 703 and stored in the section 705, and the second set of ions can be received through the back lens 710 and stored in the section 708. The ions in the first set can be separated from the ions in the second set by oscillating electric potentials generated by the multipole rods in the sections 706 and 707. For example, different oscillating dipole potentials can be generated in the sections 706 and 707 to axially confine ions in the first set and the second set, respectively. Thus ions in the section 705 can be manipulated separately from ions in the section 708. For example, precursor ions can be isolated from the first set in the section 705, and reagent ions can be isolated from the second set in the section 708. The oscillating electric potentials can be adjusted in the sections 706 and 707 to allow ions pass from the section 705 to section 708, and vice versa. For example, instead of dipole potentials, quadrupole potentials can be generated in the sections 706 and 707 to guide the ions between the sections 705 and 708. Positive and negative ions can be axially confined near the ends of the ion trap 700 by oscillating electric potentials generated by the front lens 703 and the back lens 710, or dipole potentials generated in the sections 704 and 709. In one implementation, a segmented trap, such as the ion trap 700 illustrated in FIG. 7, ion-ion reactions are occurring in a first segment. A weak pseudo potential barrier is created to partition the precursor and reagent ions from a second segment that has a lower axis DC bias potential. As the ion-ion reaction creates product ions in the first segment, some of the product ions may have sufficiently large mass-to-charge ratios and thermal kinetic energy to pass through the weak pseudo potential barrier and penetrate the second segment where they are dampened by collisions and may be captured. Thus, these product ions are removed from the first section and are no longer exposed to further reactions with reagent ions. Such removal of the product ions may reduce neutralization and subsequent loss of product ions. Method steps of the invention can be performed by one or more programmable processors executing a computer program to perform functions of the invention by operating on input data and generating output. Method steps can also be performed by, and apparatus of the invention can be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit). Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. The essential elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto-optical disks, or optical disks. Information carriers suitable for embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in special purpose logic circuitry. To provide for interaction with a user, the invention can be implemented on a computer having a display device, e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor, for displaying information to the user and a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input. A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, the steps of the described methods can be performed in a different order and still achieve desirable results. The described techniques can be applied to other ion traps or guides, such as curved axis ion guides that define a curved ion channel to trap or guide ions, planar RF ion guides (planar multipoles) and RF cylindrical ion pipes. Instead of segmented ion traps, the described techniques can also be implemented using multiple separate ion traps. | <SOH> BACKGROUND <EOH>The present invention relates to mass spectrometry. A mass spectrometer analyzes masses of sample particles, such as atoms and molecules, and typically includes an ion source, one or more mass analyzers and one or more detectors. In the ion source, the sample particles are ionized. The sample particles can be ionized with a variety of techniques that use, for example, chemical reactions, electrostatic forces, laser beams, electron beams or other particle beams. The ions are transported to one or more mass analyzers that separate the ions based on their mass-to-charge ratios. The separation can be temporal, e.g., in a time-of-flight analyzer, spatial e.g., in a magnetic sector analyzer, or in a frequency space, e.g., in ion cyclotron resonance (“ICR”) cells. The ions can also be separated according to their stability in a multipole ion trap or ion guide. The separated ions are detected by one or more detectors that provide data to construct a mass spectrum of the sample particles. In the mass spectrometer, ions are guided, trapped or analyzed using magnetic fields or electric potentials, or a combination of magnetic fields and electric potentials. For example, magnetic fields are used in ICR cells, and multipole electric potentials are used in multipole traps such as three-dimensional (“3D”) quadrupole ion traps or two-dimensional (“2D”) quadrupole traps. For example, linear 2D multipole traps can include multipole electrode assemblies, such as quadrupole, hexapole, octapole or greater electrode assemblies that include four, six, eight or more rod electrodes, respectively. The rod electrodes are arranged in the assembly about an axis to define a channel in which the ions are confined in radial directions by a 2D multipole potential that is generated by applying radio frequency (“RF”) voltages to the rod electrodes. The ions are traditionally confined axially, in the direction of the channel's axis, by DC biases applied to the rod electrodes or other electrodes such as plate lens electrodes in the trap. In a portion of the channel defined by the rod electrodes, the DC biases can generate electrostatic potentials that axially confine either positive ions or negative ions, but cannot simultaneously confine both. Additional AC voltages can be applied to the rod electrodes to excite, eject, or activate some of the trapped ions. In MS/MS experiments, selected precursor ions (also called parent ions) are first isolated or selected, and next reacted or activated to induce fragmentation to produce product ions (also called daughter ions). Mass spectra of the product ions can be measured to determine structural components of the precursor ions. Typically, the precursor ions are fragmented by collision activated dissociation (“CAD”) in which the precursor ions are kinetically excited by electric fields in an ion trap that also includes a low pressure inert gas. The excited precursor ions collide with molecules of the inert gas and may fragment into product ions due to the collisions. Product ions can also be produced by electron capture dissociation (“ECD”) or ion-ion interactions. In ECD, low energy electrons are captured by multiply charged positive precursor ions, which then may undergo fragmentation due to the electron capture. To induce ECD processes in ICR cells, the precursor ions and the electrons are radially confined by large magnetic fields, typically from about three to about nine Tesla. Axially, the positive precursor ions and the electrons are confined by electrostatic potentials in adjacent regions. Near the border of the adjacent regions, trajectories of the precursor ions and the electrons may overlap and ECD may take place. Alternatively, the trapped precursor ions may be exposed to a flux of low energy electrons. Multipole ion traps typically use RF multipole potentials to radially confine ions. An electron's mass-to-charge ratio is one hundred thousand to one million times smaller than mass-to-charge ratios of typical precursor ions. Conventional multipole traps, however, can simultaneously confine only particles whose mass-to-charge ratios do not differ more than about a few hundred times. It has been suggested that ECD can be performed in a multipole trap if additional magnetic fields are used to trap the electrons or a large flux of electrons is introduced. Ion-ion interactions have been used to generate product ions in 3D quadrupole traps, where an oscillating 3D quadrupole potential can simultaneously confine positive and negative ions in a central volume, and no electrostatic potentials are required to provide axial confinement. | <SOH> SUMMARY <EOH>In a 2D multipole ion trap or ion guide that defines an internal volume, ions are confined by oscillating electric potentials in both radial and axial directions. In general, in one aspect, the invention provides techniques for trapping or guiding ions. Ions are introduced into an ion trap or ion guide. The ion trap or ion guide includes a first set of electrodes and a second set of electrodes. The first set of electrodes defines a first portion of an ion channel to trap or guide the introduced ions. Periodic voltages are applied to electrodes in the first set of electrodes to generate a first oscillating electric potential that radially confines the ions in the ion channel, and periodic voltages are applied to electrodes in the second set of electrodes to generate a second oscillating electric potential that axially confines the ions in the ion channel. Particular implementations can include one or more of the following features. Introducing ions can include introducing positive ions and negative ions into the ion trap or ion guide. The ion trap or ion guide can include a first end and a second end, and the positive and negative ions can be introduced at the first end and the second end, respectively. The ion trap or ion guide can include two or more sections, and one or more DC biases can be applied to one or more of the sections of the ion trap or ion guide to confine the positive or the negative ions into one or more sections. Applying periodic voltages to electrodes in the first set of electrodes can include applying periodic voltages with a first frequency, and applying periodic voltages to electrodes in the second set of electrodes can include applying periodic voltages with a second frequency that is different from the first frequency. The first and second frequencies can have a ratio that is about an integer number or a ratio of integer numbers. The first and second frequencies have a ratio of about two. The first and second oscillating electric potentials can have different spatial distributions. The ion channel can have an axis, and the first oscillating electric potential can define substantially zero electric field at the axis of the ion channel, and the second oscillating electric potential can define substantially non-zero electric field at the axis of the ion channel. The first oscillating potential can includes an oscillating quadrupole, hexapole or larger multipole potential. The second oscillating potential can include an oscillating dipole potential. The first and second oscillating electric potentials can define a pseudopotential for each particular mass and charge of the introduced ions such that each of the defined pseudopotentials specifies a corresponding potential barrier along the ion channel. The first set of electrodes can include a plurality of rod electrodes. The second set of electrodes can include a plurality of rod electrodes defining a second portion of the ion channel. The second set of electrodes can include one or more plate ion lens electrodes. The second set of electrodes can include a first plate ion lens electrode at a first end of the ion channel and a second plate ion lens electrode at a second end of the ion channel. In general, in another aspect, the invention provides an apparatus. The apparatus includes a first set and a second set of electrodes and a controller. The first set of electrodes is arranged to define a first portion of an ion channel to trap or guide ions. The controller is configured to apply periodic voltages to electrodes in the first set and the second set to establish a first oscillating electric potential and a second oscillating electric potential, wherein the first and second oscillating electric potentials have different spatial distributions and confine ions in the ion channel in radial and axial directions, respectively. Particular implementations can include one or more of the following features. The controller can be configured to confine simultaneously positive and negative ions in the ion channel in both radial and axial directions. The controller can be configured to apply periodic voltages to electrodes in the first set of electrodes with a first frequency, and to electrodes in the second set of electrodes with a second frequency that is different from the first frequency. The first and second frequencies can have a ratio that is about an integer number or a ratio of integer numbers. The first set of electrodes can include a plurality of rod electrodes. The second set of electrodes can include a plurality of rod electrodes defining a second portion of the ion channel, or one or more plate ion lens electrodes. The second set of electrodes can include a first plate ion lens electrode at a first end of the ion channel and a second plate ion lens electrode at a second end of the ion channel. The invention can be implemented to provide one or more of the following advantages. Positive and negative ions can be simultaneously confined in an internal volume defined by electrode structures in a 2D multipole ion trap. Due to the simultaneous confinement in the same volume, product ions can be generated by ion-ion interactions. The 2D multipole ion trap can trap substantially more (typically, thirty to one hundred fold more) positive and negative ions than a 3D quadrupole trap. Thus, the 2D multipole trap can provide more product ions for a later analysis, which can be performed with larger signal-to-noise ratios, and low abundance product ions may also be detected. The positive and negative ions can be more conveniently introduced in a 2D multipole ion trap than into a 3D quadrupole trap. For example, the positive ions can be introduced at one end of a linear 2D multipole trap and the negative ions can be introduced at the other end. The positive ions can be precursor ions and the negative ions can be reagent ions that may induce charge transfer to or from the precursor ions. Alternatively, the positive ions can be reagent ions and the negative ions can be precursor ions. Alternatively, negative reagent ions may abstract charged species, typically one or more protons, from the precursor ion. The charge transfer can reduce a multiple charge of the precursor ion, invert the charge polarity of the precursor ion, or induce a fragmentation of the precursor ion. For precursor ions such as phosphopeptide ions, the charge transfer reaction may precipitate fragmentation that results in product ion spectra that are more informative than the product ion spectra of the same species produced with CAD alone. Such charge transfer may induce fragmentation or simply charge reduction of ions other than the precursor ions, such as fragmentation or charge reduction of the product ions produced by prior charge transfer reactions. In a linear 2D quadrupole trap or other 2D multipole rod assembly, precursor ions and reagent ions having opposite sign of charge can be trapped in the same volume both radially and axially by a superposition of RF electric potentials, without large magnetic fields. A segmented linear trap can initially store precursor ions and reagent ions in separate segments and induce fragmentation later by allowing the precursor ions and the reagent ions to interact in the same segment or segments. Before allowing their interaction, the precursor ions or the reagent ions may be manipulated in the separate segments using conventional methods, such as selecting the precursor or reagent ions by established methods of isolation. The ion-ion interactions can be stopped at any time by re-segregating the positive and negative ion populations. In a channel where an ion population includes positive ions, negative ions or both, and the ions are radially confined by electric fields defined by a primary RF potential, a secondary RF electric potential can define electric fields that selectively confine ions of the population in the axial direction of the channel based on the mass and charge of an ion, but independent of the sign of the ion's charge. Thus, axial confinement can be used as a valve or a gate that can be opened or closed to allow or block the passage of ions in the axial direction. Axial confinement can be provided by an electric potential that is generated by secondary RF voltages applied to lens end plate electrodes. In an assembly with two or more axial segments, the ions can be axially confined by applying different combination of RF voltages to multipole rods in different segments of the assembly. One or more of the segments of the assembly, can be implemented by separate 2D multipole traps. Axial confinement may also be achieved by applying secondary RF voltages to auxiliary electrodes located around, adjacent or in between the multipole rod electrodes of the multipole ion trap. Because linear ion traps are readily adapted to other mass spectrometers, after performing ion-ion reaction experiments in the linear ion traps, the product ions can be easily transported for analysis to different mass analyzers, such as TOF, FTICR or different RF ion trap mass spectrometers. Thus ion-ion experiments can use a wide range of instruments, not just 3D quadrupole ion traps. The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Unless otherwise noted, the verbs “include” and “comprise” are used in an open-ended sense—that is, to indicate that the “included” or “comprised” subject matter is a part or component of a larger aggregate or group, without excluding the presence of other parts or components of the aggregate or group. The terms “front”, “center”, and “back,” are used to denote parts of an apparatus, such as a multipole ion trap or equivalent thereof, in schematic illustrations without particular reference to the actual locations of the parts of the apparatus in any absolute sense, such as when the apparatus is inverted or rotated. Other features and advantages of the invention will become apparent from the description, the drawings and the claims. | 20040123 | 20060411 | 20051201 | 90990.0 | 0 | BERMAN, JACK I | CONFINING POSITIVE AND NEGATIVE IONS WITH FAST OSCILLATING ELECTRIC POTENTIALS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,764,448 | ACCEPTED | Transmission method, transmitter, reception method, and receiver | For the purpose of efficient transmission based on the UWB system, first and second baseband waveforms are generated at a cycle equivalent to an integral multiple of a carrier to have a specified phase difference from each other. The first baseband waveform is multiplied by the carrier and a first transmission data sequence to acquire a first transmission waveform. The second baseband waveform is multiplied by a phase shifted carrier and a second transmission data sequence to acquire a second transmission waveform. The first transmission waveform is mixed with the second transmission waveform to acquire a transmission signal. The transmission signal is transmitted as a π/2 shift BPSK signal to transmit a UWB signal. Selecting the baseband waveforms and the carrier makes it possible to configure the transmission band and easily provide division multiplexing transmission. | 1. A transmission method comprising the steps of: acquiring a carrier of a specified frequency; acquiring first and second transmission data sequences; generating a first baseband waveform of a cycle equivalent to an integral multiple of the carrier and multiplying the generated first baseband waveform by the carrier and the first transmission data sequence to acquire a first transmission waveform; generating a second baseband waveform having a specified phase difference from the first baseband waveform at the cycle equivalent to the integral multiple of the carrier and multiplying the generated second baseband waveform by the phase shifted carrier resulting from phase shift of the carrier and the second transmission data sequence to acquire a second transmission waveform; and mixing the first transmission waveform with the second transmission waveform to acquire a transmission signal and transmitting the transmission signal. 2. The transmission method according to claim 1, wherein the first and second baseband waveforms increase or decrease levels at every cycle and are provided with an approximately 180-degree phase difference from each other. 3. The transmission method according to claim 1, wherein the phase shifted carrier is a waveform resulting from shifting the carrier by approximately 90 degrees. 4. The transmission method according to claim 1, wherein at least first and second sub-bands are provided by dividing a transmission band for transmission signals; and wherein a frequency of the carrier is selected to transmit a transmission signal using the first or second sub-band. 5. The transmission method according to claim 4, wherein each of the sub-bands uses a different antenna for transmission. 6. The transmission method according to claim 1, wherein the carrier is phase-adjusted based on components included in a received signal. 7. A transmitter comprising: a carrier generation means for generating a carrier of a specified frequency; a baseband processing means for acquiring first and second transmission data sequences; a first baseband waveform generation means for generating a first baseband waveform of a cycle equivalent to an integral multiple of the carrier based on a carrier generated by the carrier generation means and multiplying the generated first baseband waveform by the carrier and the first transmission data sequence; a second baseband waveform generation means for generating a second baseband waveform having a specified phase difference from the first baseband waveform at the cycle equivalent to the integral multiple of the carrier and multiplying the generated second baseband waveform by the phase shifted carrier resulting from phase shift of the carrier and the second transmission data sequence; a mixing means for mixing a signal multiplied by the first baseband waveform generation means with a signal multiplied by the second baseband waveform generation means; and a transmission means for transmitting a signal mixed by the mixing means. 8. The transmitter according to claim 7, wherein a first baseband waveform generated by the first baseband waveform generation means and a second baseband waveform generated by the second baseband waveform generation means increase or decrease levels at every cycle and are provided with an approximately 180-degree phase difference from each other. 9. The transmitter according to claim 7, wherein the phase shifted carrier handled by the second baseband waveform generation means is a waveform resulting from shifting the carrier handled by the first baseband waveform generation means by approximately 90 degrees. 10. The transmitter according to claim 7, wherein at least first and second sub-bands are provided by dividing a transmission band for transmission signals; and wherein a frequency of the carrier is selected to transmit a transmission signal using the first or second sub-band. 11. The transmitter according to claim 10, wherein the transmission means is provided with a plurality of transmission antennas and each of the sub-bands uses a different antenna. 12. The transmitter according to claim 7, further comprising: a phase shifter to phase-adjust a carrier generated from the carrier generation means based on components included in a received signal. 13. A reception method comprising the steps of: acquiring a received carrier of a specified frequency; extracting a received signal for a transmission band, multiplying the extracted received signal by the received carrier, and sampling the multiplied signal at a specified cycle equivalent to an integral multiple of the received carrier to acquire first received data; and multiplying the received signal by a phase-shifted received carrier resulting from phase-shifting the received carrier and sampling the multiplied signal at a specified cycle equivalent to an integral multiple of the received carrier to acquire second received data. 14. The reception method according to claim 13, wherein the first and second received data are alternately selected at a specified sampling cycle to generate a unified received data sequence. 15. The reception method according to claim 13, wherein the received carrier is phase-adjusted by components extracted from data not selected in the selection process. 16. The reception method according to claim 13, wherein at least first and second sub-bands are provided by dividing a transmission band for received signals; and wherein a frequency of the received carrier is selected to transmit a received signal using the first or second sub-band. 17. The reception method according to claim 16, further comprising the step of: receiving a signal using a different antenna for each of the sub-bands and extracting the received signal using a filter provided for each of the sub-bands. 18. A receiver comprising: a carrier generation means for generating a received carrier of a specified frequency; a filter to pass a received signal for a transmission band; a first reception means for multiplying an output from the filter by the received carrier, and sampling the multiplied signal at a specified cycle equivalent to an integral multiple of the received carrier to acquire first received data; and a second reception means for multiplying an output from the filter by a phase-shifted received carrier resulting from phase-shifting the received carrier and sampling the multiplied signal at a specified cycle equivalent to an integral multiple of the received carrier to acquire second received data. 19. The receiver according to claim 18 further comprising: a selection means for alternately selecting the first and second received data at a specified sampling cycle to generate a unified received data sequence. 20. The receiver according to claim 18, wherein the received carrier generated from the carrier generation means is phase-adjusted by components extracted from data not selected in the selection process. 21. The receiver according to claim 18, wherein at least first and second sub-bands are provided by dividing a transmission band for received signals; and wherein a frequency of the received carrier is selected to transmit a received signal using the first or second sub-band. 22. The receiver according to claim 21, wherein the sub-bands are provided with a plurality of antennas for acquiring a received signal; and wherein the filter is provided for each of the sub-bands. | BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission method and a transmitter according to the ultra wide band (UWB) system and a reception method and a receiver according to the UWB system. 2. Description of Related Art Particular attention has been paid to the UWB system as one of wireless transmission systems. The UWB system realizes transmission using a very wide transmission band of, for example, several gigahertzes and using very short pulses. FIG. 13 shows a configuration example of a conventional UWB transceiver. An antenna 11 is connected to an antenna changer 13 via a band-pass filter 12. The antenna changer 13 is connected to reception-related circuits and transmission-related circuits. The antenna changer 13 functions as a selection switch to operate in interlock with transmission and reception timings. The band-pass filter 12 passes signals of transmission band widths of several gigahertzes such as 4 GHz to 9 GHz used for the system. The reception-related circuits connected to the antenna changer 13 include a low noise amplifier 14, 2-system multipliers 15I and 15Q, low pass filters 16I and 16Q, and analog-digital converters 17I and 17Q. The low noise amplifier 14 amplifies an output from the antenna changer 13 for reception. The multipliers 15I and 15Q multiply an output from the low noise amplifier 14 by outputs from pulse generators 25I and 25Q. The low pass filters 16I and 16Q eliminate high frequency components from outputs from the multipliers 15I and 15Q. The analog-digital converters 17I and 17Q sample outputs from the low pass filters 16I and 16Q. Output pulses from the pulse generator 25I and 25Q are phase-shifted from each other by the specified amount. The analog-digital converter 17I samples I-channel transmission data. The analog-digital converter 17Q samples Q-channel transmission data. Received data for each channel is supplied to the baseband circuit 30 for reception processing. In this example, received data for the I channel is used as is. Received data for the Q channel is used as an error signal. As transmission-related circuits, the multiplier 26 is supplied with transmission data output from the baseband circuit 30. The transmission data is multiplied by an output from the pulse generator 25I. The transmission data output from the baseband circuit 30 is modulated, e.g., as an NRZ (Non Return to Zero) signal. The multiplier 26 multiplies the transmission data by an output from the pulse generator 25I to generate a bi-phase modulated pulse. This becomes a signal modulated by the so-called BPSK (Binary Phase Shift Keying) system. In order to allow the pulse generator 25I to generate pulses, there is provided a Voltage Controlled Temperature Compensated Crystal Oscillator (VCTCXO, hereafter simply referred to as an oscillator) 21 to control oscillation frequencies of the oscillator 21 based on an error signal acquired from received data for the Q channel. An oscillation signal from the oscillator 21 is supplied to a PLL (phase locked loop) circuit 22. A voltage control oscillator 23 constitutes a loop for the PLL circuit 11. An oscillated output from the voltage control oscillator 23 is supplied to the pulse generator 25I to generate a pulse synchronized to the oscillated output from the oscillator 23. A phase shifter 24 supplies a pulse generator 25Q with an output from the oscillator 23 by delaying a specified cyclic phase. This makes it possible to generate a short wavelength pulse synchronized with the oscillated output from the oscillator 23 at a timing delayed from an output pulse of the pulse generator 25I. A multiplier 26 multiplies an output pulse from the pulse generator 25Q by the transmission data to use the multiplication output as a transmission signal. The transmission signal output from the multiplier 26 is supplied to a power amplifier 27 and is amplified there for transmission. The amplified output is supplied to the band-pass filter 12 via the antenna changer 13. The band-pass filter 12 limits the band to pass only signals for the transmission band. The transmission signal is then transmitted from the antenna 11. FIG. 14 shows a process example in the baseband circuit 30. A despreader circuit 31 is supplied with received data for the I and Q channels for a despread process, i.e., the reverse of transmission despreading. The despread received data for the I channel is supplied to a data demodulation circuit 32 for demodulation. The received data is then supplied to a CRC circuit 33 for error detection and correction. The processed received data is supplied to a UWB communication management and processing section 34 for processing in layers specified in this communication system. A loop filter 35 extracts an error component from the Q channel's received data despread in the despreader circuit 31. The error component is supplied as a control signal to the oscillator 21 in FIG. 13. FIG. 15 shows an example of frequency spectrum for transmission signals. The example in FIG. 15 uses a band of approximately 10 GHz. FIG. 16 exemplifies a time waveform of transmitted signals. The UWB system transmits a very short pulse of one nanosecond or less. It is known that such a short wavelength pulse has a very wide bandwidth of at least several gigahertzes on a frequency axis. Accordingly, there is provided the frequency spectrum as shown in FIG. 15. Transmission signals may be available not only in the mono-cycle (one cycle) pulse waveform as shown in FIG. 16, but also in a 2-cycle or 3-cycle pulse waveform. FIG. 17 shows a time waveform according to the 2-cycle pulse (bicycle pulse). The 2-cycle pulse can increase a transmission power compared to the 1-cycle pulse. When a signal is transmitted in this manner and is received, the received signal is held for synchronization as follows. For example, a pulse is delayed from the I-channel signal for specified amount 1. This pulse is used as a template waveform for the Q channel to find a value of correlation between the received signal and the template waveform. The oscillation phase of the oscillator is controlled based on the correlation value. FIG. 18 exemplifies a cross-correlation waveform during transmission of the 2-cycle pulse in FIG. 17. When the oscillation phase is controlled based on the correlation values as shown in FIG. 18, it becomes possible to perform reception processing in precise synchronization with received data. Non-patent document 1 outlines the UWB system. [Non-Patent Document 1] Nikkei Electronics, 11 Mar. 2002, pp. 55-66. Presently, the UWB system is subject to the FCC (Federal Communications Commission) specifications in the U.S. The FCC specifications include radiation intensities for indoor and outdoor frequency bands. For example, the transceiver in FIG. 13 needs to be configured so that the band-pass filter 12 connected to the antenna 11 can provide the spectrum compliant with the specifications. If the band-pass filter performs a process needed for this purpose, however, a filter's group delay greatly oscillates the pulse waveform, causing an inter-pulse interference. When an inter-pulse interference exists, it is necessary to increase a time interval between pulses, decreasing a chip rate. The interference can be reduced if it is possible to increase the interval between pulses by maintaining the chip rate. This has been difficult with the conventional processing. The conventional UWB system basically uses all provided transmission bands, e.g., bands permitted for use by FCC. The gigahertz bands to be used for the UWB system include bands already used for the other systems. It is necessary to limit the transmission power for the already used bands. However, the band-pass filter needs to limit transmission signal bands in order to limit only part of the bands. As mentioned above, if the band-pass filter limits bands, a filter's group delay deforms the pulse waveform and decrease the transmission efficiency. SUMMARY OF THE INVENTION The present invention has been made in consideration of the foregoing. It is therefore an object of the present invention to provide the UWB system with efficient transmission. According to a first aspect of the present invention, there is provided a transmission method comprising the steps of: acquiring a carrier of a specified frequency; acquiring first and second transmission data sequences; generating a first baseband waveform of a cycle equivalent to an integral multiple of the carrier and multiplying the generated first baseband waveform by the carrier and the first transmission data sequence to acquire a first transmission waveform; generating a second baseband waveform having a specified phase difference from the first baseband waveform at the cycle equivalent to the integral multiple of the carrier and multiplying the generated second baseband waveform by the phase shifted carrier resulting from phase shift of the carrier and the second transmission data sequence to acquire a second transmission waveform; and mixing the first transmission waveform with the second transmission waveform to acquire a transmission signal and transmitting the transmission signal. Since a transmission signal is acquired as mentioned in the first aspect of the present invention, the first and second transmission data sequences are quadrature-modulated onto transmit the signal as a so-called π/2 shift BPSK modulation wave. Selecting the carrier and each of the baseband waveforms can transmit the signal as a UWB signal that is transmitted by using an intended center frequency and the frequency band. According to a second aspect of the present invention, there is provided a reception method comprising the steps of: acquiring a received carrier of a specified frequency; extracting a received signal for a transmission band, multiplying the extracted received signal by the received carrier, and sampling the multiplied signal at a specified cycle equivalent to an integral multiple of the received carrier to acquire first received data; and multiplying the received signal by a phase-shifted received carrier resulting from phase-shifting the received carrier and sampling the multiplied signal at a specified cycle equivalent to an integral multiple of the received carrier to acquire second received data. The reception process according to the second aspect of the present invention can extract the first and second received data quadrature-modulated onto the received signal in synchronization with the received carrier. It becomes possible to receive a signal that is transmitted as the so-called π/2 shift BPSK modulation wave. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a configuration example of a communication apparatus according to an embodiment of the present invention; FIG. 2 is a block diagram showing a configuration example of an RF unit according to the embodiment of the present invention; FIG. 3 is a block diagram showing a configuration example of a baseband wave generation circuit according to the embodiment of the present invention; FIG. 4 is a configuration diagram showing part of a baseband circuit according to the embodiment of the present invention; FIG. 5 is a configuration diagram showing a configuration example of a swap circuit according to the embodiment of the present invention; FIG. 6 is a characteristic diagram exemplifying baseband waveforms according to the embodiment of the present invention; FIG. 7 exemplifies a time waveform of a π/2 shift BPSK signal according to the embodiment of the present invention; FIG. 8 shows the constellation of the π/2 shift BPSK; FIG. 9 is a characteristic diagram showing a 2-band frequency spectrum according to the embodiment of the present invention; FIG. 10 is a characteristic diagram showing a 3-band frequency spectrum according to the embodiment of the present invention; FIG. 11 is a block diagram showing another configuration example (providing a plurality of band-pass filters) of the RF unit according to the embodiment of the present invention; FIG. 12 is a block diagram showing yet another configuration example (providing a plurality of antennas and band-pass filters) of the RF unit according to the embodiment of the present invention; FIG. 13 is a block diagram showing a configuration example of a transceiver according to the conventional UWB system; FIG. 14 is a block diagram showing a configuration example of a baseband circuit in the transceiver according to the conventional UWB system; FIG. 15 is a characteristic diagram exemplifying a pulse frequency spectrum according to the conventional UWB system; FIG. 16 is a characteristic diagram exemplifying the time waveform of a pulse according to the conventional UWB system; FIG. 17 is a characteristic diagram exemplifying the frequency spectrum of a 2-cycle pulse; and FIG. 18 is a characteristic diagram exemplifying the cross-correlation waveform of a 2-cycle pulse. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in further detail with reference to the accompanying drawings, i.e., FIGS. 1 through 12. The example uses a transceiver applied to the UWB system capable of wireless transmission. FIG. 1 exemplifies the entire configuration of the transceiver according to the example. In this example, a first RF unit 100 and a second RF unit 200 are connected to a baseband unit 300. The first RF unit 100 and the second RF unit 200 perform different wireless communication processes. Specifically, for example, the band for wireless transmission in the UWB system is divided into at least lower and upper portions. The first RF unit 100 uses the lower band for communication. The second RF unit 200 uses the upper band for communication. Even if the transmission band is divided, it is not always necessary to provide a plurality of RF units as shown in FIG. 1 or use each RF unit as a special communication means for the corresponding band. This topic will be discussed later. The first RF unit 100 comprises an antenna 101, an antenna changer 102, a received pulse matched filter 103, and a transmission pulse generator 104. The antenna changer 102 is connected to the antenna 101. The received pulse matched filter 103 processes signals received at the antenna 101. The transmission pulse generator 104 generates a transmission signal. Likewise, the second RF unit 200 comprises an antenna 201, an antenna changer 202, a received pulse matched filter 203, and a transmission pulse generator 204. The antenna changers 102 and 202 function as switches to choose from the received pulse matched filter and the transmission pulse generator in interlock with transmission and reception timings. The baseband unit 300 comprises a UWB modem 391, an MAC (media access control) section 392, and a DLC (data link control) section 393. The MAC section 392 and the DLC section 393 perform processes on the corresponding layers for the access control system installed in the communication system. The MAC section 392 and the DLC section 393 are capable of various known processes or possible processes to be specified for the UWB system in the future. FIG. 2 exemplifies an internal configuration of the first RF unit 100. The antenna 101 for transmission and reception is connected to the antenna changer 102. The antenna changer 102 connects with the reception circuit constituting the received pulse matched filter 103 and the transmission circuit constituting the transmission pulse generator 104. When the same transmission band is used for transmission and reception processes, the example performs these processes in a time division manner. Referring now to FIG. 2, the following describes the reception circuit represented as the received pulse matched filter 103 in FIG. 1. The antenna changer 102 outputs a received signal to the band-pass filter 111 that passes the signal corresponding to the reception band. An output from the filter 111 is supplied to a low noise amplifier 112 that amplifies it for reception. The low noise amplifier 112 supplies the amplified output to two multipliers 113I and 113Q. The multipliers 113I and 113Q function as matched filters. That is to say, the multipliers 113I and 113Q multiply the amplified output by a carrier output from the phase shifter 124 or by a phase shifted carrier from the delay circuit 125 to extract the transmitted I-channel and Q-channel reception pulses. The delay circuit 125 delays the carrier output from the phase shifter 124 to produce the phase shifted carrier. The low pass filters 114I and 114Q are supplied with outputs from the multipliers 113I and 113Q to remove the high frequency components. The analog-digital converters 115I and 115Q are supplied with outputs from the low pass filters 114I and 114Q and sample the signals at specified timings to generate digital data. The baseband unit 300 is supplied with sampling outputs for the I and Q channels as received data RxI and RxQ for the I and Q channels, respectively. The temperature compensating oscillator 121 is provided to generate carriers. The temperature compensating oscillator 121 supplies an oscillated output to a PLL (phase locked loop) circuit 122. A voltage control oscillator 123 constitutes a loop for the PLL circuit 122. The oscillated output from the voltage control oscillator 123 is supplied to a phase shifter 124. The phase shifter 124 adjusts the phase of oscillated output from the voltage control oscillator 123 based on a phase control signal supplied from the baseband unit 300. The phase shifter 124 directly supplies the phase-adjusted signal as a carrier for reception to the multiplier 113I. The multiplier 113I multiplies the received wave by the carrier to yield an I-channel signal. The delay circuit 125 delays the output from the phase shifter 124. The carrier for reception is phase-shifted by the specified amount and is supplied to the multiplier 113Q. The multiplier 113Q multiplies the received wave by the carrier to yield a Q-channel signal. A detailed description will be given on the amount of delay for the reception carrier supplied by the delay circuit 125. Referring now to FIG. 2, the following describes the transmission circuit represented as the transmission pulse generator 104 in FIG. 1. The baseband unit 300 according to the example is configured to generate 2-channel transmission data, i.e., I-channel transmission data TxI and Q-channel transmission data TxQ. The I-channel transmission data TxI is supplied to the multiplier 136I. The multiplier 136I multiplies the I-channel transmission data TxI by signal LOI that is a result of multiplication between the carrier and a baseband waveform generated in the baseband waveform generation circuit 132I. The Q-channel transmission data TxQ is supplied to the delay circuit 131 and is delayed for a specified amount. The delayed Q-channel transmission data TxQ is supplied to the multiplier 136Q. The multiplier 136Q multiplies the Q-channel transmission data TxQ by signal LOQ that is a result of multiplication between the carrier and a baseband waveform generated in the baseband waveform generation circuit 132Q. The same delay amount is used for the delay circuits 125 and 131. The detail will be described later. Here, the delay amount for the delay circuits 125 and 131 is assumed to be Δ2. The baseband waveform generation circuits 132I and 132Q generate baseband waveforms ShapeI and ShapeQ that increase and decrease parabolically and repeatedly at specified cycles. Examples of the baseband waveforms ShapeI and ShapeQ will be also described later. The two baseband waveform generation circuits 132I and 132Q generate the same waveform. Only the waveform's phases are shifted approximately 180 degrees from each other. The multiplier 133I is supplied with the baseband waveform ShapeI generated from the baseband waveform generation circuit 132I. The multiplier 133I multiplies ShapeI by the carrier output from the phase shifter 124 to generate a multiplied signal LOI. The multiplier 133Q is supplied with the baseband waveform ShapeQ generated in the baseband waveform generation circuit 132Q. The multiplier 133Q multiplies ShapeQ by the carrier output from the phase shifter 124 to generate a multiplied signal LOQ. Multiplied outputs from the multipliers 133I and 133Q are supplied to the multipliers 136I and 136Q, respectively. The multiplied outputs are further multiplied by transmission data TxI and TxQ. Multiplied outputs are supplied to the adder 134 that adds them to each other to generate a 1-channel signal. A power amplifier 135 amplifies the 1-channel signal to yield a transmission signal. The antenna changer 102 supplies the transmission signal to the antenna 101 for wireless transmission. FIG. 3 exemplifies configurations of the baseband waveform generation circuits 132I and 132Q. A clock input terminal 140I is supplied with an I-channel clock (carrier) A clock input terminal 140Q is supplied with a Q-channel clock (carrier). These clocks are supplied from the phase shifter 124 and may be referred to as carriers in the following description. There is provided a specified phase between the I-channel clock CLK I and the Q-channel clock CLK Q. The I-channel clock CLK I is supplied to four clock input terminals D flip-flops 141 through 144 provided for the baseband waveform generation circuit 132I. The D flip-flop 141 generates Q output Q1 that is then supplied to a D input terminal of the next D flip-flop 142. The D flip-flop 142 generates Q output Q2 that is then supplied to a D input terminal of the next D flip-flop 143. The D flip-flop 143 generates Q output Q3 that is then supplied to a D input terminal of the next D flip-flop 144. The D flip-flop 144 generates inverted Q output Q4 that is then supplied to a D input terminal of the D flip-flop 141. The Q output Q1 from the D flip-flop 141 is supplied to the adder 148 via a coefficient multiplier 145. The Q output Q2 from the D flip-flop 142 is supplied to the adder 148 via a coefficient multiplier 146. The adder 148 adds both outputs. An added output from the adder 148 is supplied to the adder 149. The Q output Q3 from the D flip-flop 143 is supplied to the adder 149 via a coefficient multiplier 147. The adder 149 adds both signals to yield the baseband waveform ShapeI. An example of the baseband waveform ShapeI will be described later. Here, the coefficient multiplier 146 uses coefficient 2 for multiplication. The other coefficient multipliers 145 and 147 use coefficient 1 for multiplication. The adder 149 outputs the baseband waveform ShapeI that is then supplied to the multiplier 133I. The multiplier 133I multiplies the baseband waveform ShapeI by the clock CLK I, i.e., the I-channel carrier. A multiplied output from the multiplier 133I is supplied to the multiplier 136I. The multiplier 136I multiplies the output by the transmission data TxI and supplies a multiplied output to the adder 134. The three D flip-flops 141, 142, and 143 in the baseband waveform generation circuit 132I generate inverted Q outputs that are then supplied to the baseband waveform generation circuit 132Q. In the baseband waveform generation circuit 132Q, the inverted Q output from the D flip-flop 141 is supplied to an adder 157 via a delay circuit 151 and a coefficient multiplier 154. The inverted Q output from the D flip-flop 142 is supplied to the adder 157 via a delay circuit 152 and a coefficient multiplier 155. The adder 157 adds both signals. The inverted Q output from the D flip-flop 143 is supplied to an adder 158 via a delay circuit 153 and a coefficient multiplier 156. The adder 158 adds the inverted Q output and the added output from the adder 157. The adder 158 yields an added output as the baseband waveform ShapeQ. An example of the baseband waveform ShapeI will be described later. Here, the coefficient multiplier 155 uses coefficient 2 for multiplication. The other coefficient multipliers 154 and 156 use coefficient 1 for multiplication. The multiplier 133Q is supplied with the baseband waveform ShapeQ output from the adder 158. The multiplier 133Q multiplies the baseband waveform ShapeQ by the clock CLK Q, i.e., the Q-channel carrier. A multiplied output from the multiplier 133Q is supplied to the multiplier 136Q. The multiplier 136Q multiplies the multiplied output by the transmission data TxQ and supplies the multiplied output to the adder 134. The adder 134 adds an output from the multiplier 136I and an output from the multiplier 136Q and supplies an added output to the power amplifier 135 for transmission (see FIG. 2). According to the configuration in FIG. 3, the baseband waveform ShapeI is multiplied by the carrier. The multiplied signal is then multiplied by the transmission data. The sequence of multiplication may be specified otherwise. With reference to FIG.4, the following describes part of received data processing in the UWB modem 391 of the baseband unit 300. When the baseband unit 300 is supplied with the I-channel and Q-channel received data RxI and RxQ, the despreader 301 performs a despread process, i.e., the reverse of transmission despreading. The despreader 301 then supplies the despread received data RxI and RxQ for both channels to a swap circuit 302. The swap circuit 302 unifies the received data for both channels and outputs a signal for detecting phase error information. A configuration example of the swap circuit 302 will be described later. After the swap circuit 302 unifies the received data, the demodulator 303 demodulates the received data in compliance with the modulation for transmission. The demodulated data is supplied to an error correction section 304. The error correction section 304 performs error correction using the CRC (Cyclic Redundancy Check) code, for example. The error-corrected data is supplied to the other processing sections such as the MAC section 392 and the DLC section 393 in the baseband unit 300. The swap circuit 302 supplies a loop filter 306 with the output signal for acquiring the phase error information. The loop filter 306 extracts the phase error information that is then supplied as a phase control signal to the phase shifter 124 in FIG. 2. FIG. 5 exemplifies a configuration of the swap circuit 302. FIGS. 5A and 5B show two switching states of one swap circuit 302. As shown in FIG. 5, the swap circuit 302 comprises four selection switches 311 through 314 and a sign inverter 315. The swap circuit 302 is capable of alternately selecting the switching states in FIGS. 5A and 5B. In one switching state of the swap circuit 302 as shown in FIG. 5A, the I-channel received data RxI is supplied to the demodulator 303 via the selection switches 311 and 313. The Q-channel received data RxQ is supplied to the loop filter 306 via the selection switches 312 and 314. In the other switching state of the swap circuit 302 as shown in FIG. 5B, the Q-channel received data RxQ is supplied to the demodulator 303 via the selection switches 312 and 313. The I-channel received data RxI is supplied to the loop filter 306 via the selection switch 311, the sign inverter 315, and the selection switch 314. The following describes transmission and reception process states of the transceiver according to the above-mentioned configuration. FIG. 6 shows baseband waveforms generated during a transmission process. As mentioned above, the baseband unit 300 outputs 2-channel transmission data, i.e., the I-channel transmission data TxI and the Q-channel transmission data TxQ. The delay circuit 131 provides delay amount Δ2 for the 2-channel transmission data TxI and TxQ to cause different timings between them. There is provided a phase difference of approximately 180 degrees between transmission data TxI of FIG. 6(a) and transmission data TxQ of FIG. 6(j). The clock CLK I of FIG. 6(b) as the carrier and the CLK Q of FIG. 6(k) are configured to the frequency of cycles T0 through T7, i.e., eight times as fast as one chip of transmission data. The clock CLK Q has a period of cycles equivalent to an integral multiple (4 times in this example) of the clock CLK I and is configured to the timing that is later than the clock (carrier) by a 90-degree phase. The delay of the clock CLK Q from the clock CLK I is equivalent to the delay amount Δ2 provided by the above-mentioned delay circuits 125 and 131. Based on the clock CLK I of FIG. 6(b), the baseband waveform generation circuit 132I generates the baseband waveform ShapeI of FIG. 6(h). That is to say, when the clock CLK I is supplied to the baseband waveform generation circuit 132I, the D flip-flops 141, 142, 143, and 144 output pulse waveforms Q1, Q2, Q3, and Q4 of FIG. 6(c), 6(d), 6(e), and 6(f), respectively, which are shifted one clock cycle from each other. These pulse waveforms are added to be output as the baseband waveform ShapeI of FIG. 6(h). The baseband waveform ShapeI is a cyclic waveform and repeatedly increases and decreases parabolically in units of eight cycles of the clock CLK I. The multiplier 133I multiplies the baseband waveform ShapeI of FIG. 6(h) by the clock CLK I to generate the signal LOI of FIG. 6(i). In the signal LOI, the wave height of the clock CLK I corresponds to the level of the baseband waveform ShapeI. The multiplier 136I multiplies the signal LOI by the transmission data TxI of FIG. 6(a) to pulse-modulate the transmission data TxI. Based on the clock CLK Q of FIG. 6(j), the baseband waveform generation circuit 132Q generates the baseband waveform ShapeQ of FIG. 6(o). That is to say, the D flip-flops 141, 142, and 143 supply the baseband waveform generation circuit 132Q with inverted outputs Q1, Q2, and Q3 of FIG. 6(l), 6(m), and 6(n), respectively, which are pulse waveforms shifted one clock cycle from each other. These pulse waveforms are added to be output as the baseband waveform ShapeQ of FIG. 6(o). The baseband waveform ShapeQ is a cyclic waveform and repeatedly increases and decreases parabolically in units of eight cycles of the clock CLK I. The baseband waveform ShapeQ is phase-shifted from the baseband waveform ShapeI (FIG. 6(h)) by 180 degrees. The 180-degree phase shift is equivalent to a half-chip shift from the viewpoint of the chip cycle for the I-channel and Q-channel transmission data. The phase here assumes that one cycle of the baseband waveform corresponds to 360 degrees. The multiplier 133Q multiplies the baseband waveform ShapeQ of FQG. 6(o) by the clock CLK Q to generate the signal LOQ of FQG. 6(p). In the signal LOQ, the wave height of the clock CLK Q corresponds to the level of the baseband waveform ShapeQ. The multiplier 136Q multiplies the signal LOQ by the transmission data TxQ of FIG. 6(j) to pulse-modulate the transmission data TxQ. The adder 134 in FIG. 3 adds a multiplied output from the multiplier 136I and a multiplied output from the multiplier 136Q to mix pulse-modulated signals from the transmission data TxI and TxQ. As a result, a transmission signal is generated by mixing the I-channel and Q-channel signals and maintaining the orthogonal relationship. The transmission signal is amplified and processed otherwise and is transmitted wirelessly. FIG. 7 exemplifies a time waveform of the transmission signal generated by mixing the I-channel and Q-channel signals in the adder 134. In FIG. 7, the Q-channel signal is shown in a thick line. The I-channel signal is shown in a thin line. The Q-channel signal is delayed from the I-channel signal by an amount resulting from adding a half chip of the transmission data and a 90-degree shift of the clock (carrier) together. When the I-channel and Q-channel transmission data are modulated, their pulse amplitudes vary almost reversely to each other. Since the I-channel and Q-channel signals are shifted by the amount equivalent to 90 degrees of the carrier, both signals are phase-shifted by 90 degrees. The modulation of transmission signals generated in this manner is referred to as π/2 shift BPSK (Binary Phase Shift Keying). FIG. 8 shows the constellation of π/2 shift BPSK signals generated in this manner. When a space is assumed to be formed by crossing the I axis and the Q axis orthogonally to each other, the I-channel signal is positioned to either of two points (0 and π) on the I axis as shown in FIG. 8(a). The Q-channel signal is positioned to either of two points (1/2π and 3/2π) on the Q axis as shown in FIG. 8(b). FIG. 8(c) shows the constellation of mixing the I-channel and Q-channel signals that alternately shift to each other by approximately a half chip. This makes it possible to alternately activate either of two points on the I axis and either of two points on the Q axis. Consequently, with respect to a signal change, the signal appears at every sampling position approximately 90 degrees earlier or later than the most recent signal. This means a π/2 shift at every sampling position. When receiving the signal that is transmitted in this manner, the RF unit performs the I-channel reception process and the Q-channel reception process independently of each other as shown in FIG. 2 to acquire the respective channel signals. The swap circuit 302 in FIG. 5 is provided to swap an I-channel signal and a Q-channel signal for every sample to generate single-channel received data. The baseband section just needs to realize a conventional process for single-channel received data. If the baseband section is configured to independently process the I-channel and Q-channel received data, however, the swap circuit 302 is unnecessary. In this example, the selection switch 314 selects a signal at the reverse side of the signal selected by the selection switch 313 in the swap circuit 302 during reception. The signal selected by the selection switch 314 is supplied to the loop filter 306 and is used as a phase error signal for phase adjustment of the carrier. This makes it possible to adjust the carrier phase to the received signal and provide excellent transmission by synchronizing the transmitting side with the receiving side. In this case, the sign inverter 315 reverses the sign to solve the difference between a delay (negative value) of the I channel against the Q channel and a delay (positive value) of the Q channel against the I channel. The provision of the sign inverter 315 can always ensure the same sign for the error signal appearing in a signal supplied to the loop filter and prevent the loop filter from canceling values. Since the π/2 shift BPSK modulation is used to pulse-modulate signals to be transmitted as UWB signals, the clock frequency determines the center frequency of the transmission band for a signal to be transmitted. Further, the clock frequency and the baseband waveform determine the bandwidth. For example, the transmission signal can comply with the UWB signal specifications. Unlike the conventional transmission processing of UWB signals, the transmission circuit need not use the band-pass filter to limit transmission signal bands. There is provided an effect of avoiding characteristics deterioration due to the use of the band-pass filter for band limitation. According to the example, the I-channel and Q-channel signal components can be orthogonally crossed to each other and can be transmitted as a UWB signal. When the chip rate is constant, the chip length can be doubled in comparison with the conventional case of transmitting a BPSK-modulated UWB signal, making it possible to decrease the interference between chips. When the same chip length is used, signals can be transmitted at double the rate compared to the prior art. Since selecting a carrier frequency or the like easily sets transmission bands, an intended transmission band can be easily determined for the transmission signal. As shown in FIG. 1, for example, there are provided two RF units, i.e., the first RF unit 100 for lower band communication and the second RF unit 200 for upper band communication. In this case, as shown in FIG. 9, the first RF unit 100 can easily generate and transmit UWB signals for communication in the 4 GHz band. The second RF unit 200 can easily generate and transmit UWB signals for communication in the 7 to 9 GHz band. A thick line in FIG. 9 indicates the FCC compliant level for each frequency. A low power density is assigned to bands used for the GPS (Global Positioning System). Within this specification range, however, the approximately 5 GHz band is often used for the wireless LAN (Local Area Network). As shown in FIG. 9, the lower band is defined above the 5 GHz band. The upper band is defined below the 5 GHz band. This can provide an effective transmission system for UWB signals by avoiding the interference with the existing wireless LAN (WLAN). The upper band above the 5 GHz may be further divided into sub-bands. As shown in FIG. 10, a total of three transmission bands may be provided. The lower band comprises a 4 GHz band. The upper band comprises two bands, i.e., a 7 GHz band and a 9 GHz band. In this case, a special RF unit may be provided for each of three transmission bands. Alternatively, one RF unit may be used to choose from two or three transmission bands for transmission or reception. The lower band or the upper band may be further divided into more sub-bands than those mentioned above. With reference to FIGS. 11 and 12, the following describes configuration examples of providing three transmission bands as shown in FIG. 10 and using one RF unit to process transmission and reception of the three transmission bands. The mutually corresponding parts of the RF unit in FIGS. 11, 12, and 2 are designated by the same reference numerals. The RF unit in FIG. 11 differs from FIG. 2 in the connection configuration of the band-pass filter between the antenna changer 102 and the low noise amplifier 112 as a reception amplifier. According to the configuration in FIG. 11, the antenna changer 102 outputs a received signal that is then supplied to the selection switch 161. A selection switch 161 functions to choose from three band-pass filters 162, 163, and 164 having pass band characteristics corresponding to the reception band at that time. A selection switch 165 functions in interlock with the selection switch 161 and selects one of outputs from the band-pass filters 162, 163, and 164. The selected output is supplied to the low noise amplifier 112. When three bands are configured as shown in FIG. 10, three band-pass filters 162, 163, and 164 correspond to specific pass bands. That is to say, the band-pass filter 162 passes the 4 GHz band. The band-pass filter 163 passes the 7 GHz band. The band-pass filter 164 passes the 9 GHz band. A PLL circuit 122 is configured to be able to selectively generate carriers f1, f2, and f3 correspondingly to the respective bands. This configuration can use one RF unit to easily switch between the transmission bands. According to this configuration, only the reception system requires the band-pass filters. One band-pass filter needed for the reception system passes the bandwidth of a sub-band. Accordingly, the band-pass filter just needs to pass a relatively narrow band. It is possible to use band-pass filters having relatively excellent characteristics. The other parts of the RF unit in FIG. 11 may be configured similarly to those of the RF unit in FIG. 2. FIG. 12 shows another example of the RF unit. The RF unit in FIG. 12 independently provides not only the band-pass filters, but also antennas and antenna changers correspondingly to the transmission bands. The output from the power amplifier 135 for transmission supplies an output to a selection switch 173. The selection switch 173 can selectively supply the transmission signal to three antenna changers 172a through 172c. The antenna changer 172a, 172b, and 172c are connected to antennas 171a, 171b, and 171c. The antennas 171a, 171b, and 171c are provided with appropriate transmission and reception bands. For example, the antenna 171a is appropriate for transmission and reception of 4 GHz band signals. The antenna 171b is appropriate for transmission and reception of 7 GHz band signals. The antenna 171c is appropriate for transmission and reception of 9 GHz band signals. Output sides of the antenna changer 172a, 172b, and 172c for the received signal connect with band-pass filters 174a, 174b, and 174c having different pass band characteristics. A selection switch 175 selects one of outputs from the band-pass filters 174a, 174b, and 174c and supplies the selected output to the low noise amplifier 112. The selection switch 173 and the selection switch 175 operate in interlock with band settings for transmission and reception. The three band-pass filters 174a, 174b, and 174c correspond to specific bands. For example, the band-pass filter 174a passes 4 GHz band signals. The band-pass filter 174b passes 7 GHz band signals. The band-pass filter 174c passes 9 GHz band signals. The PLL circuit 122 is configured to be able to selectively generate carriers f1, f2, and f3 correspondingly to the respective bands. The other parts of the RF unit in FIG. 12 may be configured similarly to those of the RF unit in FIG. 2. The above-mentioned configuration makes it possible to select not only the band-pass filter for reception, but also the antenna for transmission and reception so that the transmission band can be optimized. It is possible to further improve the transmission and reception characteristics. The above-mentioned embodiment has shown examples of the frequency bands used as the transmission bands and the number of divisions. It is to be distinctly understood that the other frequencies and values may be selected within the spirit and scope of the invention. The above-mentioned embodiment has described the example of the communication apparatus dedicated to transmission and reception. Further, for example, a personal computer for various data processing may be mounted with a board or a card designed for the communication processing equivalent to the RF unit according to the embodiment. The computer may be provided with the software to perform the processing in the baseband section. The transmission method and the transmitter according to the present invention quadrature-modulate the first and second transmission data sequences to transmit a so-called π/2 shift BPSK modulated wave. Accordingly, the efficient transmission becomes available compared to the case of transmitting a BPSK-modulated UWB signal, for example. When the chip rate is assumed to be constant, for example, the chip length can be doubled compared to a conventional BPSK modulation wave. Selecting the baseband waveform and the carrier frequency makes it possible to properly select the transmission frequency and the bandwidth for a transmission signal. This enables the UWB transmission in compliance with frequency division multiplexing, for example. In this case, it is unnecessary to use the band-pass filter that controls transmission signal bands to limit transmission bandwidths. It becomes possible to solve the problem of interfering with transmission waveforms due to the use of the band-pass filter and improve the transmission characteristics. Since the frequency division multiplexing uses the independent transmission antenna for each sub-band, it is possible to use the transmission antenna appropriate for each divided frequency band and further improve the transmission characteristics. The reception method and the receiver according to the present invention can extract the first and second received data quadrature-modulated onto the received signal in synchronization with the received carrier. It becomes possible to receive and demodulate a signal that is transmitted as the so-called π/2 shift BPSK modulation wave. Therefore, it is also possible to receive efficiently transmitted signals. In this case, the first and second received data are alternately selected at a specified sampling cycle to generate a unified received data sequence. It becomes possible to extract two pieces of quadrature-modulated received data. During the alternate selection, components extracted from the unselected data are used for phase adjustment of the received carrier. This can easily provide efficient phase adjustment of the received carrier and improve the reception characteristics. The independent reception antennas are used for corresponding sub-bands when receiving signals that are transmitted in accordance with the frequency division multiplexing. It is possible to use the reception antennas appropriate for the respective divided frequency bands, making it possible to further improve the reception characteristics. Moreover, it is possible to use filters appropriate the reception bands by selecting the filters for the corresponding reception bands. Also from this point of view, the reception characteristics can be improved. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to a transmission method and a transmitter according to the ultra wide band (UWB) system and a reception method and a receiver according to the UWB system. 2. Description of Related Art Particular attention has been paid to the UWB system as one of wireless transmission systems. The UWB system realizes transmission using a very wide transmission band of, for example, several gigahertzes and using very short pulses. FIG. 13 shows a configuration example of a conventional UWB transceiver. An antenna 11 is connected to an antenna changer 13 via a band-pass filter 12 . The antenna changer 13 is connected to reception-related circuits and transmission-related circuits. The antenna changer 13 functions as a selection switch to operate in interlock with transmission and reception timings. The band-pass filter 12 passes signals of transmission band widths of several gigahertzes such as 4 GHz to 9 GHz used for the system. The reception-related circuits connected to the antenna changer 13 include a low noise amplifier 14 , 2-system multipliers 15 I and 15 Q, low pass filters 16 I and 16 Q, and analog-digital converters 17 I and 17 Q. The low noise amplifier 14 amplifies an output from the antenna changer 13 for reception. The multipliers 15 I and 15 Q multiply an output from the low noise amplifier 14 by outputs from pulse generators 25 I and 25 Q. The low pass filters 16 I and 16 Q eliminate high frequency components from outputs from the multipliers 15 I and 15 Q. The analog-digital converters 17 I and 17 Q sample outputs from the low pass filters 16 I and 16 Q. Output pulses from the pulse generator 25 I and 25 Q are phase-shifted from each other by the specified amount. The analog-digital converter 17 I samples I-channel transmission data. The analog-digital converter 17 Q samples Q-channel transmission data. Received data for each channel is supplied to the baseband circuit 30 for reception processing. In this example, received data for the I channel is used as is. Received data for the Q channel is used as an error signal. As transmission-related circuits, the multiplier 26 is supplied with transmission data output from the baseband circuit 30 . The transmission data is multiplied by an output from the pulse generator 25 I. The transmission data output from the baseband circuit 30 is modulated, e.g., as an NRZ (Non Return to Zero) signal. The multiplier 26 multiplies the transmission data by an output from the pulse generator 25 I to generate a bi-phase modulated pulse. This becomes a signal modulated by the so-called BPSK (Binary Phase Shift Keying) system. In order to allow the pulse generator 25 I to generate pulses, there is provided a Voltage Controlled Temperature Compensated Crystal Oscillator (VCTCXO, hereafter simply referred to as an oscillator) 21 to control oscillation frequencies of the oscillator 21 based on an error signal acquired from received data for the Q channel. An oscillation signal from the oscillator 21 is supplied to a PLL (phase locked loop) circuit 22 . A voltage control oscillator 23 constitutes a loop for the PLL circuit 11 . An oscillated output from the voltage control oscillator 23 is supplied to the pulse generator 25 I to generate a pulse synchronized to the oscillated output from the oscillator 23 . A phase shifter 24 supplies a pulse generator 25 Q with an output from the oscillator 23 by delaying a specified cyclic phase. This makes it possible to generate a short wavelength pulse synchronized with the oscillated output from the oscillator 23 at a timing delayed from an output pulse of the pulse generator 25 I. A multiplier 26 multiplies an output pulse from the pulse generator 25 Q by the transmission data to use the multiplication output as a transmission signal. The transmission signal output from the multiplier 26 is supplied to a power amplifier 27 and is amplified there for transmission. The amplified output is supplied to the band-pass filter 12 via the antenna changer 13 . The band-pass filter 12 limits the band to pass only signals for the transmission band. The transmission signal is then transmitted from the antenna 11 . FIG. 14 shows a process example in the baseband circuit 30 . A despreader circuit 31 is supplied with received data for the I and Q channels for a despread process, i.e., the reverse of transmission despreading. The despread received data for the I channel is supplied to a data demodulation circuit 32 for demodulation. The received data is then supplied to a CRC circuit 33 for error detection and correction. The processed received data is supplied to a UWB communication management and processing section 34 for processing in layers specified in this communication system. A loop filter 35 extracts an error component from the Q channel's received data despread in the despreader circuit 31 . The error component is supplied as a control signal to the oscillator 21 in FIG. 13 . FIG. 15 shows an example of frequency spectrum for transmission signals. The example in FIG. 15 uses a band of approximately 10 GHz. FIG. 16 exemplifies a time waveform of transmitted signals. The UWB system transmits a very short pulse of one nanosecond or less. It is known that such a short wavelength pulse has a very wide bandwidth of at least several gigahertzes on a frequency axis. Accordingly, there is provided the frequency spectrum as shown in FIG. 15 . Transmission signals may be available not only in the mono-cycle (one cycle) pulse waveform as shown in FIG. 16 , but also in a 2-cycle or 3-cycle pulse waveform. FIG. 17 shows a time waveform according to the 2-cycle pulse (bicycle pulse). The 2-cycle pulse can increase a transmission power compared to the 1-cycle pulse. When a signal is transmitted in this manner and is received, the received signal is held for synchronization as follows. For example, a pulse is delayed from the I-channel signal for specified amount 1. This pulse is used as a template waveform for the Q channel to find a value of correlation between the received signal and the template waveform. The oscillation phase of the oscillator is controlled based on the correlation value. FIG. 18 exemplifies a cross-correlation waveform during transmission of the 2-cycle pulse in FIG. 17 . When the oscillation phase is controlled based on the correlation values as shown in FIG. 18 , it becomes possible to perform reception processing in precise synchronization with received data. Non-patent document 1 outlines the UWB system. [Non-Patent Document 1] Nikkei Electronics, 11 Mar. 2002, pp. 55-66. Presently, the UWB system is subject to the FCC (Federal Communications Commission) specifications in the U.S. The FCC specifications include radiation intensities for indoor and outdoor frequency bands. For example, the transceiver in FIG. 13 needs to be configured so that the band-pass filter 12 connected to the antenna 11 can provide the spectrum compliant with the specifications. If the band-pass filter performs a process needed for this purpose, however, a filter's group delay greatly oscillates the pulse waveform, causing an inter-pulse interference. When an inter-pulse interference exists, it is necessary to increase a time interval between pulses, decreasing a chip rate. The interference can be reduced if it is possible to increase the interval between pulses by maintaining the chip rate. This has been difficult with the conventional processing. The conventional UWB system basically uses all provided transmission bands, e.g., bands permitted for use by FCC. The gigahertz bands to be used for the UWB system include bands already used for the other systems. It is necessary to limit the transmission power for the already used bands. However, the band-pass filter needs to limit transmission signal bands in order to limit only part of the bands. As mentioned above, if the band-pass filter limits bands, a filter's group delay deforms the pulse waveform and decrease the transmission efficiency. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention has been made in consideration of the foregoing. It is therefore an object of the present invention to provide the UWB system with efficient transmission. According to a first aspect of the present invention, there is provided a transmission method comprising the steps of: acquiring a carrier of a specified frequency; acquiring first and second transmission data sequences; generating a first baseband waveform of a cycle equivalent to an integral multiple of the carrier and multiplying the generated first baseband waveform by the carrier and the first transmission data sequence to acquire a first transmission waveform; generating a second baseband waveform having a specified phase difference from the first baseband waveform at the cycle equivalent to the integral multiple of the carrier and multiplying the generated second baseband waveform by the phase shifted carrier resulting from phase shift of the carrier and the second transmission data sequence to acquire a second transmission waveform; and mixing the first transmission waveform with the second transmission waveform to acquire a transmission signal and transmitting the transmission signal. Since a transmission signal is acquired as mentioned in the first aspect of the present invention, the first and second transmission data sequences are quadrature-modulated onto transmit the signal as a so-called π/2 shift BPSK modulation wave. Selecting the carrier and each of the baseband waveforms can transmit the signal as a UWB signal that is transmitted by using an intended center frequency and the frequency band. According to a second aspect of the present invention, there is provided a reception method comprising the steps of: acquiring a received carrier of a specified frequency; extracting a received signal for a transmission band, multiplying the extracted received signal by the received carrier, and sampling the multiplied signal at a specified cycle equivalent to an integral multiple of the received carrier to acquire first received data; and multiplying the received signal by a phase-shifted received carrier resulting from phase-shifting the received carrier and sampling the multiplied signal at a specified cycle equivalent to an integral multiple of the received carrier to acquire second received data. The reception process according to the second aspect of the present invention can extract the first and second received data quadrature-modulated onto the received signal in synchronization with the received carrier. It becomes possible to receive a signal that is transmitted as the so-called π/2 shift BPSK modulation wave. | 20040127 | 20070109 | 20050113 | 86496.0 | 0 | LE, LANA N | TRANSMISSION METHOD, TRANSMITTER, RECEPTION METHOD, AND RECEIVER | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,764,570 | ACCEPTED | Premixed fuel burner assembly | A premixed fuel burner assembly includes a hollow tubular burner body, a hollow tubular venturi tube and a distribution plate. The burner body is a hollow tube having a open end and a closed end. The burner body also has a longitudinal porting area within which are formed a plurality of radially formed slots. The hollow tubular venturi tube is positioned within the burner body along the longitudinal axis extending from said first end. The distribution plate has a mid-section and longitudinal flanges. The flanges of the distribution plate are coupled to the inside surface of burner body and said mid-section has a plurality of holes formed within. The distribution plate is axially aligned and positioned within said burner body such that said holes of distribution plate are positioned adjacent the radially formed slots within said burner body. | 1. A premixed fuel burner assembly, comprising: (a) a hollow tubular burner body having a longitudinal axis, said burner body having a longitudinal porting area having formed within a plurality of radially formed slots, said burner body having a open end and a closed end; (b) a hollow tubular venturi tube positioned within said burner body along said longitudinal axis extending from said open end; (c) a distribution plate having longitudinal mid-section and flanges, said flanges being coupled to the inside surface of burner body, said mid-section having a plurality of holes formed within, and said distribution plate being positioned within said burner body such that the holes of distribution plate are positioned adjacent to the radially formed slots within said burner body and extending from said open end to said closed end of burner body. 2. The fuel burner assembly of claim 1, wherein the holes of the distribution plate are of variable size. 3. The fuel burner assembly of claim 1, wherein the holes of the distribution plate are larger at the open end and smaller at the closed end. 4. The fuel burner assembly of claim 1, wherein said holes of the distribution plate are circular. 5. The fuel burner assembly of claim 1, wherein said venturi tube extends a length from said open end that is substantially shorter than the length of said distribution plate. 6. The fuel burner assembly of claim 1, wherein said porting slots are rectangular. 7. A method of making a fuel burner assembly, said method comprising the steps: (a) forming a tubular burner body having an open end and a closed end; (b) cutting a plurality of radial slots formed within said tubular body; (c) forming a hollow tubular venturi tube and positioning it within said burner body along said longitudinal axis extending from said open end partially into said burner body; (d) forming a distribution plate with longitudinal mid-section and flanges; (e) cutting a plurality of holes within the mid-section; and (f) coupling the flanges of the distribution plate to the inside surface of burner body such that the distribution plate is positioned between the inside surface of the burner body and the venturi tube and such that the holes within the mid-section are positioned adjacent the slots of said burner body. 9. The method of claim 7, wherein the length of said venturi tube extends for only a portion of the entire length of the burner body. 10. The method of claim 7, wherein the length of said distribution plate extends the entire length of the burner body. 11. The method of claim 7, wherein step (e) comprises cutting holes within the distribution plate of variable size. 12. The method of claim 7, wherein the holes within the distribution plate are larger at the first end and smaller at the second end. 13. The method of claim 7, wherein the porting slots are cut to be rectangular. | This application claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional Application No. 60/442,514, filed Jan. 27, 2003. FIELD OF THE INVENTION This invention relates to fuel burner equipment and more particularly to a premixed fuel burner assembly. BACKGROUND OF THE INVENTION Premixed fuel burner assemblies are used with various heating equipment such as boilers, commercial hot water headers, fuel barbeques, and the like. Fuel burners are devices into which a flow of combustible fuel (usually gas) is introduced into a mixing chamber, where it is mixed with air supplied in a suitable proportion to the combustible gas. After mixing, the mixture of combustible fuel and air exits the mixing chamber through burner ports where it is ignited and burnt. Specifically, a typical premixed fuel burner assembly consists of a hollow burner body having a closed end and an open end into which the premixed fuel/air flows. The burner body includes a porting area that consists of burner flame port perforations (i.e. slots and/or holes). Within the burner body is a venturi tube that typically contains a multiplicity of holes through and out which the fuel and air mixture from the interior of the body flows. Fuel and air are both provided into the boiler body through the venturi tube. Specifically, fuel is provided into the venturi tube through a fuel nozzle and air is provided around the fuel nozzle. Fuel and gas are mixed to produce a combustible mixture which subsequently is passed through the burner body and ignited to produce a burner flame that, in the case of a water heater is applied to the a heat exchanger of the boiler. Conventional premixed fuel burner assemblies produce short flames that are just beyond or above the burner porting area. Normally the mixture has 30 percent excess air so as to provide cleaner combustion products. At loadings (i.e. heat per unit area) below approximately 6 kilowatts per square decimeter, the burner port surface will be radiant since the velocity of the mixture is low resulting in the flame being positioned on or closely adjacent to the surface. This gives rise to problems of thermal fatigue and high temperature oxidation of the burner porting surface, and potential flashback of the flame into the burner body. At higher loadings (e.g. 12 kilowatts per square decimeter and above) the increase in volumetric flow is such that the velocity of the mixture may be increased to the point where the flame front is further from the burner porting surface resulting in a relatively cool porting surface. However, at high loadings if the amount of excess air is not or cannot be controlled, overheating of burner porting surface can still result when there is inadequate excess air (i.e. when there is too much fuel in the air/fuel mixture) since in such a case the flame will sit on the surface of the burner increasing the temperature. As is conventionally known, when the burner body becomes too hot (e.g. 2000 degrees Celcius) the fuel burner assembly can suffer failures, melting and irreversible damage. Various types of fuel burner assemblies have been developed to attempt to maintain the flames above the surface of the outer cylinder by operating at high loadings (i.e. high fuel/air velocities) while at the same time maintaining a proper mix of fuel and flame stability. For example, U.S. Pat. No. 6,461,152 to Wood et al. discloses a tubular burner consisting of a cylindrical tubular body into which a distributor component can be fitted. The distributor is substantially the same axial length as the tubular burner body but of a smaller cross-sectional dimension than said body so to allow for easy insertion. The distributor divides the burner body into an upper and a lower chamber. The distributor has a first tubular portion and a second extension portion each of which is provided with axially aligned flanges having a number of perforations. While this assembly achieves a reasonable distribution of air and fuel streams prior to delivering the fuel/air mixture to the porting area of the tubular burner, the construction and assembly of this burner is expensive, as is the manufacture of the various components involved in the construction. SUMMARY OF THE INVENTION The invention provides in one aspect, a premixed fuel burner assembly, comprising: (a) a hollow tubular burner body having a longitudinal axis, said burner body having a longitudinal porting area having formed within a plurality of radially formed slots, said burner body having a first end and a second end: (b) a hollow tubular venturi tube positioned within said burner body along said longitudinal axis extending from said first end; (c) a distribution plate having a mid-section and longitudinal flanges, said flanges being coupled to the inside surface of burner body, said mid-section having a plurality of holes formed within, and said distribution plate being positioned within said burner body such that the holes of distribution plate are positioned adjacent to the radially formed slots within said burner body. The invention provides in another aspect, a method of making a fuel burner assembly, said method comprising the steps: (a) forming a tubular burner body; (b) cutting a plurality of radial slots formed within said tubular body; (c) forming a hollow tubular venturi tube and positioning it within aid burner body along said longitudinal axis extending from said first end; (d) forming a distribution plate with a mid-section and longitudinal flanges; (e) cutting a plurality of holes within the mid-section; and (f) coupling the flanges of the distribution plate to the inside surface of burner body such that the distribution plate is positioned between the inside surface of the burner body and the venturi tube and such that the holes within the mid-section are positioned adjacent the slots of said burner body. Further aspects and advantages of the invention will appear from the following description taken together with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings: FIG. 1 is a side perspective view of the premixed fuel burner assembly of the present invention; FIG. 2 is a side perspective view of the premixed fuel burner assembly of the present invention with internal components of the premixed fuel burner assembly being shown in dotted outline; FIG. 3 is an radial cross-sectional view of the premixed fuel burner assembly of FIG. 2 taken along line B-B′ of FIG. 2; and FIG. 4 is a longitudinal cross-sectional view of the pre-mixed fuel burner assembly in use illustrating the position of flames in respect of the burner body. DETAILED DESCRIPTION OF THE INVENTION Referring to FIGS. 1, 2 and 3, illustrated therein is a premixed fuel burner assembly 10 made in accordance with a preferred embodiment of the present invention. Fuel burner assembly 10 consists of a burner body 12, a conventional fuel/air mixing venturi tube 14 (FIGS. 2 and 3), and a distribution plate 16. Venturi tube 14 and distribution plate 16 are positioned within burner body 12 and together ensure good mixing of the fuel and air as the fuel/air mixture is urged through burner body 12 and an even and raised flame profile on the porting area of burner body 12 to minimize thermal fatigue and oxidation effects on burner body 12. Additionally, since fuel burner assembly 10 generates a high velocity of a well mixed fuel/air stream throughout the fuel burner assembly 10 such that excess air is evenly provided throughout the mixture, flame flashback and instability effects are inhibited. Burner body 12 is a hollow cylindrical tube having preferably having a circular cross-section. However, it should be understood that burner body 12 could also have various shaped cross-sections (e.g. oval, rectangular, polygon, etc.) depending on the particular use of burner body 12. For example, in the case where burner body 12 has an oval cross-section, the height of the combustion chamber can be minimized by orienting the minor axis in the vertical direction. Burner body 12 has a longitudinal axis A and is axially aligned with venturi tube 14 and distribution plate 16 as will be described. Burner body 12 is closed at one end 20 and open at the other end 22. The closed end 20 and open end 22 are formed using conventionally known crimping techniques. The open end 22 is adapted to receive and mount one end of venturi tube 14 and distribution plate 16 as will be described The closed end of burner body 12 is closed so that burning is confined within burner body 12. It should be understood that burner body 12 may be manufactured out of any high temperature resistant metal (e.g. stainless steel, aluminized steel, coated steel, etc.) Finally, burner body 12 should be understood to be any burner having an outer surface that defines an internal cavity in which venturi tube 14 and distribution plate 16 can be disposed. As shown, the surface of burner body 12 includes a porting area 17 within which are formed a plurality of burner ports 18. Burner ports 18 consist of a plurality of small radially oriented rectangular slots arranged in an offset manner as shown. Burner ports 18 keep the flame front 50 (FIG. 4) off of the surface of the deck while maintaining a stable flame which results in the surface of the burner body 12, and in particular, the porting area 17 being maintained at a relatively low temperature. Burn r ports 18 are of an appropriate size for a particular application. For example, if fuel burner assembly is to be us d within a hot water heater, burner ports 18 may be approximately 6 mm by 0.75 mm. Due to the equal configuration of burner ports 18 as well as the even distribution of mixed fuel/air above distribution plate 16 as will be discussed, an equal flame 60 height along the entire porting area 17 is provided (see FIG. 4). Referring to FIGS. 2 and 3, venturi tube 14 is a hollow cylindrical tube having either a circular or oval cross-section. It should be understood that venturi tube 14 may be manufactured out of any high temperature resistant metal (e.g. stainless steel, aluminized steel, coated steel, etc.) Venturi tube 14 is axially aligned with the longitudinal axis of burner body 12 and positioned within burner body 12 along a short longitudinal section of burner body 12 from the open end 22 into the area within burner body 12. The remainder of venturi tube 14 extends out of the open end 22 of burner body 12 and out of the combustion chamber and being attached to and spaced from a gas injection member (not shown) connected to a source of gas (e.g. natural gas outside of the water header). The exterior surface of venturi tube 1 4 where it enters the combustion chamber is sealed using an end cap 42. Flange 41 (FIGS. 1 and 2) is adapted to be fastened to an appliance in which fuel burner assembly 10 is used. End cap 42 is preferably formed using beeding and crimping methods to eliminate the necessity of welding, although welding can also be utilized. Accordingly, air is only provided through the venturi tube 14. Preferably, three spacers (not shown) are used to maintain a centered longitudinal position for venturi tube 14. A mixture of fuel and air is provided to venturi tube 14 through a fuel nozzle (not shown). The length and diameter of venturi tube 14 are selected to provide for proper mixing of fuel with air. Specifically, venturi tube 14 is sized so that more air than is required for combustion is provided (e.g. 30%) to reduce the maximum flame temperature and to provide cleaner combustion products (i.e. lower levels of toxic NOx and carbon monoxide emissions) such that a high velocity of air/fuel mixture is provided to the area within burner body 12 underneath the porting area 17 of burner body 12. Referring to FIGS. 2 and 3, distribution plate 16 is a long plate having a C-shaped cross-section. Distribution plate 16 is adapted to axially aligned with the longitudinal axis of burner body 12 and to fit within minor section of burner body 12 directly underneath longitudinal porting area 17 It should be understood that distribution plate 16 may be manufactured out of any high temperature resistant metal (e.g stainless steel, aluminized steel, coated steel, etc.) Distribution plate 16 has two longitudinal folded flanges 24 and 26 and a mid-section 26. A plurality of evenly spaced holes 28 is formed within the surface of mid-section 26. Longitudinal folded flanges 24 and 26 (FIG. 3) are shaped to contact the inside surface of burner body 12 along its longitudinal length as shown. The exterior surface of flanges 24 and 26 of distribution plate 16 are coupled to the inside surface of burner body 12 using an appropriate conventionally known welding technique (e.g. spot welding or seem welding techniques). Flanges 24 and 26 are coupled to the inside surface of burner body 12 such that that the mid-section 26 of distribution plate 16 is positioned underneath the longitudinal porting area 17 of burner body. Specifically, distribution plate 16 is positioned within burner body 12 such that the plane defined by the holes 28 within mid-section 26 of distribution plate is oriented along and collinear with the longitudinal axis of burner body 12 and such that holes 28 are positioned adjacent the burner ports 18 within porting area 17. Holes 28 on distribution plate 16 are of variable size. The size of each hole 28 varies according to its position on distribution plate 16. Specifically, holes 28 are largest at one end of distribution plate 16 and smallest at the other end. The end at which holes 28 are the largest is intended to be located at the open end of fuel burner assembly 10 and the end at which holes 28 are smallest is intended to be located at the closed end 20 of fuel burner assembly 10. Preferably, holes 28 are one of two sizes, where larger sized holes 30 clustered at the open end 22 and a small sized holes 32 which extend the length from the end of the cluster of the larger sized holes 31 until the closed end 20. It should b understood that while only two sizes of holes ar shown and described, any form of gradient of hole size is contemplated. Specifically, in between the ends of distribution plate 16, holes 28 can be gradually reduced in size as they traverse from the open end 22 of fuel burner assembly 10 to the closed end of fuel burner assembly 10. Further, various patterns or configurations of holes 28 are also contemplated depending on the particular functionality required by a particular application. The holes 28 within distribution plate 16 allow for improved mixing of fuel and air between the distribution plate 16 and the inside surface of burner body 12 (i.e. “mixing chamber D” as shown in FIG. 4). The presence of larger holes at the closed end 20 and smaller holes at the open end 22, provides for a higher degree of turbulence at the open end 22 of burner tube 12 and a lower degree of turbulence at the closed end 20. Since fuel and air streams are being discharged at the open end 22, increased amount of turbulence is needed at the open end 22 By directing an increased amount of turbulence to the open end 22 part of fuel burner assembly 10, an improved efficiency in mixing of fuel and air streams can be achieved. In prior art fuel burner assemblies, turbulence is provided evenly at both open and closed ends of the burner assembly, resulting in unnecessary turbulence at the closed end and not enough turbulence at the open end for optimal fuel and air mixing. Accordingly, the specific arrangement of holes 28 within distribution plate 16 in conjunction with the shorted extent of venturi tube 14 together produce a substantially evenly distributed mixture of air and fuel within mixing chamber D and accordingly even and highly set flames 5 above porting area of burner body 12. Further, this is provided without a high pressure drop. FIG. 4 is a cross-sectional view of fuel burner assembly 10 illustrating how flames 50 sit above the porting surface 17 of burner body 12 at a distance represented by “C”. This is the case due to the improved mixing capability of fuel burner assembly 10 and accordingly it's ability to maintain flame stability at high fuel/air mixture velocities (i.e. high loading). Specifically, the volume d fined by between the top surface of distribution plate 16 and inside surface of burner body 16 constitutes a mixing chamber D which receives a mixed air/fuel stream through holes 28 in mid-section of distribution plate 16 and which redistributes the mixed air/fuel stream through burner ports 18 in burner body 12. The mixing chamber constitutes a volume that is semi-circular in cross-section and which runs the entire length of burner body 12 The holes 28 within (smaller holes 32 are shown in FIG. 4 since the closed end 20 section of fuel burner assembly 10 is shown) distribution plate 16 allow for improved mixing of fuel and air within the mixing chamber D. Further, by using larger holes at the closed end 20 and smaller holes at the open end 22, increased turbulence is produced at the open end 22 of burner tube 12 as compared to the closed end 20. Accordingly, flame flashback is prevented since distribution plate 1 6 physically prevents fuel from coming back to venturi tube 14. Accordingly, fuel burner assembly 10 is designed to maintain flames above the surface of burner body 12 by operating at high loadings (i.e. high fuel/air velocities) while at the same time maintaining a proper mix of fuel and flame stability. Fuel burner assembly 10 achieves these features through the use of a particularly perforated distribution plate 16 (i.e. variable sized holes 28) as discussed in conjunction with a partially extending venturi tube to optimize the mixing process between fuel and air streams. As will be apparent to persons skilled in the art, various modifications and adaptations of the structure described above are possible without departure from the present invention, the scope of which is defined in the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>Premixed fuel burner assemblies are used with various heating equipment such as boilers, commercial hot water headers, fuel barbeques, and the like. Fuel burners are devices into which a flow of combustible fuel (usually gas) is introduced into a mixing chamber, where it is mixed with air supplied in a suitable proportion to the combustible gas. After mixing, the mixture of combustible fuel and air exits the mixing chamber through burner ports where it is ignited and burnt. Specifically, a typical premixed fuel burner assembly consists of a hollow burner body having a closed end and an open end into which the premixed fuel/air flows. The burner body includes a porting area that consists of burner flame port perforations (i.e. slots and/or holes). Within the burner body is a venturi tube that typically contains a multiplicity of holes through and out which the fuel and air mixture from the interior of the body flows. Fuel and air are both provided into the boiler body through the venturi tube. Specifically, fuel is provided into the venturi tube through a fuel nozzle and air is provided around the fuel nozzle. Fuel and gas are mixed to produce a combustible mixture which subsequently is passed through the burner body and ignited to produce a burner flame that, in the case of a water heater is applied to the a heat exchanger of the boiler. Conventional premixed fuel burner assemblies produce short flames that are just beyond or above the burner porting area. Normally the mixture has 30 percent excess air so as to provide cleaner combustion products. At loadings (i.e. heat per unit area) below approximately 6 kilowatts per square decimeter, the burner port surface will be radiant since the velocity of the mixture is low resulting in the flame being positioned on or closely adjacent to the surface. This gives rise to problems of thermal fatigue and high temperature oxidation of the burner porting surface, and potential flashback of the flame into the burner body. At higher loadings (e.g. 12 kilowatts per square decimeter and above) the increase in volumetric flow is such that the velocity of the mixture may be increased to the point where the flame front is further from the burner porting surface resulting in a relatively cool porting surface. However, at high loadings if the amount of excess air is not or cannot be controlled, overheating of burner porting surface can still result when there is inadequate excess air (i.e. when there is too much fuel in the air/fuel mixture) since in such a case the flame will sit on the surface of the burner increasing the temperature. As is conventionally known, when the burner body becomes too hot (e.g. 2000 degrees Celcius) the fuel burner assembly can suffer failures, melting and irreversible damage. Various types of fuel burner assemblies have been developed to attempt to maintain the flames above the surface of the outer cylinder by operating at high loadings (i.e. high fuel/air velocities) while at the same time maintaining a proper mix of fuel and flame stability. For example, U.S. Pat. No. 6,461,152 to Wood et al. discloses a tubular burner consisting of a cylindrical tubular body into which a distributor component can be fitted. The distributor is substantially the same axial length as the tubular burner body but of a smaller cross-sectional dimension than said body so to allow for easy insertion. The distributor divides the burner body into an upper and a lower chamber. The distributor has a first tubular portion and a second extension portion each of which is provided with axially aligned flanges having a number of perforations. While this assembly achieves a reasonable distribution of air and fuel streams prior to delivering the fuel/air mixture to the porting area of the tubular burner, the construction and assembly of this burner is expensive, as is the manufacture of the various components involved in the construction. | <SOH> SUMMARY OF THE INVENTION <EOH>The invention provides in one aspect, a premixed fuel burner assembly, comprising: (a) a hollow tubular burner body having a longitudinal axis, said burner body having a longitudinal porting area having formed within a plurality of radially formed slots, said burner body having a first end and a second end: (b) a hollow tubular venturi tube positioned within said burner body along said longitudinal axis extending from said first end; (c) a distribution plate having a mid-section and longitudinal flanges, said flanges being coupled to the inside surface of burner body, said mid-section having a plurality of holes formed within, and said distribution plate being positioned within said burner body such that the holes of distribution plate are positioned adjacent to the radially formed slots within said burner body. The invention provides in another aspect, a method of making a fuel burner assembly, said method comprising the steps: (a) forming a tubular burner body; (b) cutting a plurality of radial slots formed within said tubular body; (c) forming a hollow tubular venturi tube and positioning it within aid burner body along said longitudinal axis extending from said first end; (d) forming a distribution plate with a mid-section and longitudinal flanges; (e) cutting a plurality of holes within the mid-section; and (f) coupling the flanges of the distribution plate to the inside surface of burner body such that the distribution plate is positioned between the inside surface of the burner body and the venturi tube and such that the holes within the mid-section are positioned adjacent the slots of said burner body. Further aspects and advantages of the invention will appear from the following description taken together with the accompanying drawings. | 20040127 | 20060530 | 20050303 | 66530.0 | 0 | BASICHAS, ALFRED | PREMIXED FUEL BURNER ASSEMBLY | SMALL | 0 | ACCEPTED | 2,004 |
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10,764,658 | ACCEPTED | Pulse interleaving in doppler ultrasound imaging | Ultrasonic acoustic imaging finds many uses, particularly in the field of non-invasive medical testing. Detection of Doppler shifted acoustic frequencies permits observation of flow of a particle-containing liquid, for example, blood flow. In order to see slower moving blood by Doppler ultrasound investigation, as the blood moves from major blood vessels into arterioles and capillaries, it is necessary to lower the pulse repetition frequency. The herein disclosed invention is an interleaving technique that lowers the effective pulse repetition frequency at each probe position without exacting these system penalties. | 1. A method for determining flow of a particle-containing fluid at a plurality of determined locations in a subject body comprising: a) transmitting a series of pulses of ultrasonic acoustic energy into the body from a probe, the probe consisting essentially of an array of transmitter and detector elements; b) assigning the elements to a plurality of element groups comprising at least a first group and a second group; c) sequentially transmitting at least a first pulse from the first group of transmitter elements and a second pulse from the second group of transmitter elements until all groups of elements have transmitted pulses into a respective portion of the studied region of the subject body adjacent to each group of transmitter elements; d) repeating Step c) until a full dwell of pulses has been transmitted from each group of transmitter elements into each respective portion of the subject body and collecting Doppler shift data from reflections from each respective portion of the subject body; e) repeating Step d) until sufficient Doppler shift data has been collected from detector elements adjacent to each portion of the subject body to permit calculations of fluid flow at a desired signal to noise ratio. 2. The method of claim 1 comprising computing and storing or displaying an indication of the flow of the fluid | PRIORITY This application is a CIP of U.S. application Ser. No. 09/926,666, filed Nov. 30, 2001 and depends for priority on U.S. Provisional Application No. 60/446,162, filed Feb. 10, 2003. Application Ser. No. 09/926,666 depends for priority on International application PCT/US00/14691, filed May 26, 2000. The International application depends for priority on U.S. Provisional Applications No. 60/136,364 filed May 28, 1999, No. 60/138,793 filed Jun. 14, 1999 and No. 60/152,886 filed Sep. 8, 1999. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to ultrasonic acoustic imaging, primarily for medical purposes. 2. Brief Description of the Background Art Ultrasonic acoustic imaging finds many uses, particularly in the field of non-invasive medical testing. Direct detection of the emitted acoustic frequency permits, for example, prenatal fetal imaging. Detection of Doppler shifted acoustic frequencies permits observation of flow of a particle-containing liquid, for example, blood flow. Acoustic imaging equipment utilizes a probe that is applied to the skin of the patient overlying the part of the body being investigated. At the end of the probe is an array of transducers, usually piezoelectric, that are excited by bursts of electrical energy at the ultrasonic frequency and modulated to transmit pulses of ultrasonic energy into the body region being investigated. The subsurface structures reflect some of that energy, either at the transmitted frequency or Doppler shifted, back to the probe, where it is detected by piezoelectric receiver elements in the probe. One application of this technology to the three dimensional mapping and tracking of blood flow is disclosed in parent U.S. application Ser. No. 09/926,666, which is scheduled to issue on Jan. 27, 2004 as U.S. Pat. No. 6,682,483. The pertinent text of that application is included herein below. SUMMARY OF THE INVENTION In order to see slower moving blood by Doppler ultrasound investigation, as the blood moves from major blood vessels into arterioles and capillaries, it is necessary to lower the pulse repetition frequency. This permits the phase of the Doppler-shifted signal to change more measurably from one pulse to the next. However, if the frame rate is lowered to lower the pulse repetition frequency, less data is collected in a given time, exacting a penalty in less averaging and reducing the signal to noise ratio below the desired level. The herein disclosed invention is an interleaving technique that lowers the effective pulse repetition frequency at each probe position without exacting these system penalties. DETAILED DESCRIPTION OF THE INVENTION In this novel technique, each measurement frame consists of a progressive scan in which successive pulses are transmitted to groups of transmitter elements in different portions of the probe and the sequence periodically repeated. The data gathered from each group of elements is analyzed to study the portion of the subject adjacent to that group of elements. Thus, the pulse repetition frequency at each position is lowered. For example, instead sending and receiving N pulses from transmitter position 1 and then sending N pulses from transmitter position 2, etc., the effective pulse repetition frequency at each position is halved without lowering the frame rate or lowering the total number of pulses transmitted per frame, by interleaving 2N pulses between positions one and two. That is, first a pulse is transmitted from transmitter position 1, the next pulse from transmitter position 2, the next pulse from transmitter position 1, and then back to 2, etc. Thus, while the frame takes twice as long to complete, data studying two different positions in the subject is gathered. However, since the data from N pulses is gathered at each position, the desired signal-to-noise ratio is preserved. To reduce the pulse repetition frequency and, hence, the lowest visible Doppler frequency by a factor of I, where I is an integer, we interleave between I transmitter positions so as not to reduce the number of pulses actually used. That is, we transmit pulses 1 to I from transmitter positions 1 to I. For an N-pulse dwell (N pulses per transmitter position), we complete the dwell in NI pulse repetition intervals instead of N, but we complete I dwells in that time interval, thus gathering data focused on I different locations in the volume being studied. Each dwell consists of enough pulses to accomplish the desired measurement at the desired signal to noise ratio. The disclosure that follows illustrates the exemplary use of Doppler shifted acoustic imaging to map and track blood flow. It illustrates the techniques and systems that profit from application of the herein disclosed invention. Alternative probe geometries to which the herein disclosed invention could be profitably applied are illustrated in U.S. Pat. No. 6,524,253 B1, which is incorporated by reference herein in its entirety. SUMMARY OF THE INVENTION There is provided, in accordance with the present invention, a new, useful, and unobvious method of determining parameters of blood flow, such as vector velocity, blood flow volume, and Doppler spectral distribution, using sonic energy (ultrasound) and a novel thinned array. Also provided is a novel method of tracking blood flow and generating a three dimensional image of a blood vessel of interest that has much greater resolution than images produced using heretofore known ultrasound devices and methods. Broadly, the present invention extends to a method for determining a parameter of blood flow in a blood vessel of interest, comprising the steps of: a) providing an array of sonic transducer elements, wherein the element spacing in the array is greater than, equal or less than a half wavelength of the sonic energy produced by the elements, wherein at least one element transmits sonic energy, and a portion of the elements receive sonic energy; b) directing sonic energy produced by the at least one element of the array into a volume of the subject's body having the blood vessel of interest, c) receiving echoes of the sonic energy from the volume of the subject's body having the blood vessel of interest; d) reporting the echoes to a processor programmed to i) Doppler process the echoes to determine radial velocity of the blood flowing in the blood vessel of interest; ii) calculate a three dimensional position of blood flow in the vessel of interest; and iii) calculate the parameter of blood flow in the blood vessel at the three dimensional position calculated in step (ii); and (e) displaying the parameter on a display monitor that is electrically connected to the processor. Moreover, a method of the present invention permits an operator examining a subject to obtain information on blood flow in a particular region of the blood vessel of interest. As used herein, the phrases “element spacing” and “distance between the elements” can be used interchangeably and refer to the distance between the center of elements of an array. Various methods can be used to determine the three dimensional position of blood flow. In a particular embodiment, the method comprises the steps of having the processor programmed to: i) determine a sum beam, an azimuth difference beam and an elevation difference beam from the echoes received from the blood vessel of interest; ii) modulate the directions of the transmitted and received sonic energy based upon the sum, azimuth difference and elevation difference beams in order to lock on to the highest Doppler energy calculated from echoes from the flow of blood in the blood vessel of interest, and iii) calculate the three dimensional position of the highest Doppler energy from the blood flow in the vessel of interest. Optionally, the processor can also be programmed to determine at least one additional beam having an angle between the azimuth difference beam and the elevation difference beam prior to modulating the directions of the transmitted and received sonic energy, wherein the at least one additional beam is used to modulate the directions of the transmitted and received sonic energy. Naturally, the angle of the at least one additional beam can vary. In a particular embodiment, the at least one additional beam is at an angle that is orthogonal to the blood vessel of interest. Moreover, the present invention extends to a method as described above, wherein steps (b) through (e) are periodically repeated so that the three dimensional position of blood flow in the vessel of interest is tracked, and the parameter of blood flow is periodically calculated and displayed on the display monitor. In a particular embodiment, the period of time between repeating steps (b) through (e) is sufficiently short so that the parameter being measured remains constant, e.g., 20 milliseconds. The present invention further extends to a method for determining a parameter of blood flow in a particular region of a blood vessel of interest, comprising the steps of: a) providing an array of sonic transducer elements, wherein the element spacing in the array is greater than, equal or less than a half wavelength of the sonic energy produced by the elements, wherein at least one element transmits sonic energy, and a portion of the elements receive sonic energy; b) directing sonic energy produced by the at least one element of the array into a volume of the subject's body having the particular region of the blood vessel of interest, c) receiving echoes of the sonic energy from the volume of the subject's body having the particular region of the blood vessel of interest; d) reporting the echoes to a processor programmed to i) Doppler process the echoes to determine radial velocity of the blood flowing in the particular region of the blood vessel of interest; ii) calculate a three dimensional position of blood flow in the particular region of the blood vessel of interest; and iii) calculate the parameter of blood flow in the particular region of the blood vessel of interest at the three dimensional position calculated in step (ii); and (e) displaying the parameter on a display monitor that is electrically connected to th processor. A particular method of calculating the three dimensional position of blow flow in such a method of the present invention comprises having the processor programmed to: i) determine a sum beam, an azimuth difference beam and an elevation difference beam from the echoes received from the particular region of the blood vessel of interest; ii) modulate the directions of the transmitted and received sonic energy based upon the sum, azimuth difference and elevation difference beams in order to lock on to the highest Doppler energy calculated from echoes received from the flow of blood in the particular region of the blood vessel of interest, and iii) calculate the three dimensional position of the highest Doppler energy from the blood flow in the particular region of the blood vessel of interest. As explained above, at least one additional beam can also be determined and used to calculate the three dimensional position. Furthermore, the present invention extends to a method for determining a parameter of blood flow in a blood vessel of interest, comprising the steps of: a) providing an array of sonic transducer elements, wherein the element spacing in the array is greater than, equal or less than a half wavelength of the sonic energy produced by the elements, wherein at least one element transmits sonic energy, and a portion of elements receive sonic energy; b) directing sonic energy produced by the at least one element of the array into a volume of the subject's body having the blood vessel of interest, c) receiving echoes of the sonic energy from the volume of the subject's body having the blood vessel of interest; d) reporting the echoes to a processor electrically connected to the elements of the array, wherein the processor is programmed to i) Doppler process the echoes to determine radial velocity of the blood flowing in the blood vessel of interest; ii) determine a sum beam, an azimuth difference beam and an elevation difference beam from the echoes received from the blood vessel of interest; iii) modulate the directions of the transmitted and received sonic energy based upon the sum, azimuth difference and elevation difference beams in order to lock on to the highest Doppler energy calculated from echoes from the flow of blood in the blood vessel of interest, iv) calculate the three dimensional position of the highest Doppler energy from the blood flow in the vessel of interest; and v) calculate the parameter of blood flow in the blood vessel at the three dimensional position calculated in step (iv); and (e) displaying the parameter on a display monitor that is electrically connected to the processor. As explained above, an operator performing a method of the present invention can obtain blood flow parameters from a blood vessel of interest, and even from a particular region of a blood vessel of interest. Moreover, the present invention extends to a method for determining a parameter of blood flow in a particular region of a blood vessel of interest, comprising the steps of: a) providing an array of sonic transducer elements, wherein the element spacing in the array is greater than, equal or less than a half wavelength of the sonic energy produced by the elements, wherein at least one element transmits sonic energy, and a portion of the elements receive sonic energy; b) directing sonic energy produced by the at least one element of the array into a volume of the subject's body having the particular region of the blood vessel of interest, c) receiving echoes of the sonic energy from the volume of the subject's body having the particular region of blood vessel of interest; d) reporting the echoes to a processor electrically connected to the elements of the array, wherein the processor is programmed to i) Doppler process the echoes to determine radial velocity of the blood flowing in the particular region of the blood vessel of interest; ii) determine a sum beam, an azimuth difference beam and an elevation difference beam from the echoes received from the particular region of the blood vessel of interest; iii) modulate the directions of the transmitted and received sonic energy based upon the sum, azimuth difference and elevation difference beams in order to lock on to the highest Doppler energy calculated from echoes from the flow of blood in the particular region of the blood vessel of interest, iv) calculate the three dimensional position of the highest Doppler energy from the blood flow in the particular region of the blood vessel of interest; and v) calculate the parameter of blood flow in the particular region of the blood vessel at the three dimensional position calculated in step (iv); and (e) displaying the parameter on a display monitor that is electrically connected to the processor. In another embodiment, the present invention extends to a device for determining a parameter of blood flow in a blood vessel of interest, comprising: a) an array of sonic transducer elements, wherein the element spacing in the array is greater than, equal or less than a half wavelength of the sonic energy produced by the elements, and at least one element transmits sonic energy, and a portion of the elements receive sonic energy; b) a processor electrically connected to the array so that echoes received from a volume of the subject's body having the blood vessel of interest due to directing sonic energy produced by the at least one element of the array into the subject's body is reported to the processor, wherein the processor is programmed to: i) Doppler process the echoes to determine radial velocity of the blood flowing in the blood vessel of interest; ii) calculate a three dimensional position of blood flow in the blood vessel of interest; and iii) calculate the parameter of blood flow in the blood vessel of interest at the three dimensional position calculated in step (ii); and (c) a display monitor that is electrically connected to the processor which displays the parameter of blood flow calculated by the processor. A parameter of blood that can be determined with a device of the present invention includes blood flow volume, vector velocity, Doppler spectral distribution, etc. The parameter being measured can be an instantaneous value, or an average value determined over a heart cycle. Moreover, the present invention extends to a device as described above, wherein the processor is programmed to: i) determine a sum beam, an azimuth difference beam and an elevation difference beam from the echoes received from the blood vessel of interest after Doppler processing the echoes; ii) modulate the directions of the transmitted and received sonic energy based upon the sum, azimuth difference and elevation difference beams in order to lock on to the highest Doppler energy calculated from echoes from the flow of blood in the blood vessel of interest, iii) calculate the three dimensional position of the highest Doppler energy from the blood flow in the vessel of interest; and iv) calculate the parameter of blood flow in the blood vessel of interest at the three dimensional position calculated in (iii). Optionally, a processor of a device of the present invention can be further programmed to determine at least one additional beam having an angle between the azimuth difference beam and the elevation difference beam prior to modulating the directions of the transmitted and received sonic energy, wherein the at least one additional beam is used to modulate the directions of the transmitted and received sonic energy. In a particular embodiment, the at least one additional beam is at an angle that is orthogonal to the blood vessel of interest. Moreover, in a another embodiment of a device of the present invention, the distance between the elements of the array is greater than ½ the wavelength of the sonic energy generated by the at least one element. Furthermore, the present invention extends to a device for determining a parameter of blood flow in a blood vessel of interest, comprising: a) an array of sonic transducer elements, wherein the element spacing in the array is greater than, equal or less than a half wavelength of the sonic energy produced by the elements, and at least one element transmits sonic energy, and portion of the elements receive sonic energy; b) a processor electrically connected to the array so that echoes received from a volume of the subject's body having the blood vessel of interest due to directing sonic energy produced by the at least one element of the array into the subject's body is reported to the processor, wherein the processor is programmed to: i) Doppler process the echoes to determine radial velocity of the blood flowing in the blood vessel of interest; ii) calculate a three dimensional position of blood flow in the blood vessel of interest; and iii) calculate the parameter of blood flow in the blood vessel of interest at the three dimensional position calculated in step (ii) (c) a display monitor that is electrically connected to the processor which displays the parameter of blood flow calculated by the processor. Particular parameters of blood flow that can be determined with a device of the present invention include, but certainly are not limited to blood flow volume, vector velocity, and Doppler spectral distribution. The parameter being measured can be an instantaneous value, or an average value determined over a heart cycle. In addition, a processor of a device of the present invention can be further programmed to determine at least one additional beam having an angle between the azimuth difference beam and the elevation difference beam prior to modulating the directions of the transmitted and received sonic energy, wherein the at least one additional beam is used to modulate the directions of the transmitted and received sonic energy. In a particular embodiment, the at least one additional beam is at an angle that is orthogonal to the blood vessel of interest. Moreover, the present invention extends to a method for generating a three dimensional image using sonic energy of a blood vessel of interest in a subject, the method comprising the steps of: a) providing an array of sonic transducer elements, wherein the element spacing in the array is greater than, equal or less than a half wavelength of the sonic energy produced by the elements, wherein at least one element transmits sonic energy, and a portion of the elements receive sonic energy; b) directing sonic energy produced by the at least one element of the array into a volume of the subject's body having the blood vessel of interest, c) receiving echoes of the sonic energy from the volume of the subject's body having the blood vessel of interest; d) reporting the echoes to a processor programmed to i) Doppler process the echoes to determine radial velocity of the blood flowing in the blood vessel of interest; ii) calculate a three dimensional position of blood flow in the blood vessel of interest; iii) repeat steps (i) through (ii) to generate a plurality of calculated three dimensional positions; and vi) generate a three dimensional image of the blood vessel of interest from the plurality of calculated three dimensional positions; and (e) displaying the three dimensional image on a display monitor that is electrically connected to the processor. Furthermore, the present invention permits an operator utilizing a method of the present invention to generate a three dimensional image of not only a blood vessel in the body, but even a particular region of a blood vessel in the body. Numerous means available for calculating the three dimensional position of a blood vessel and even a particular portion of a blood vessel are encompassed by the present invention. A particular means comprises having the programmed processor: i) determine a sum beam, an azimuth difference beam and an elevation difference beam from the echoes received from the blood vessel of interest after Doppler processing the echoes; ii) modulate the directions of the transmitted and received sonic energy based upon the sum, azimuth difference and elevation difference beams in order to lock on to the highest Doppler energy calculated from echoes from the flow of blood in the blood vessel of interest, and iii) calculate the three dimensional position of the highest Doppler energy from the blood flow in the vessel of interest, and iv) repeat steps (i) through (iii) to generate a plurality of calculated three dimensional positions. Optionally, a proIcessor of a method of the present invention can also be programmed to determine at least one additional beam having an angle between the azimuth difference beam and the elevation difference beam prior to modulating the directions of the transmitted and received sonic energy, and the at least one additional beam is also used to modulate the directions of the transmitted and received sonic energy, and calculate the three dimensional position of the highest Doppler energy. In a particular embodiment, the at least one additional beam is at an angle that is orthogonal to the blood vessel of interest. The present invention also extends to a method for generating a three dimensional image of a blood vessel of interest in a subject using sonic energy, the method comprising the steps of: a) providing an array of sonic transducer elements, wherein the element spacing in the array is greater than, equal or less than a half wavelength of the sonic energy produced by the elements, wherein at least one element transmits sonic energy, and a portion of the elements receive sonic energy; b) directing sonic energy produced by the at least one element of the array into a volume of the subject's body having the blood vessel of interest, c) receiving echoes of the sonic energy from the volume of the subject's body having the blood vessel of interest; d) reporting the echoes to a processor programmed to i) Doppler process the echoes to determine radial velocity of the blood flowing in the blood vessel of interest; ii) determine a sum beam, an azimuth difference beam and an elevation difference beam from the echoes received from a portion of the blood vessel of interest; iii) modulate the directions of the transmitted and received sonic energy based upon the sum, azimuth difference and elevation difference beams in order to lock on to the highest Doppler energy calculated from echoes from the flow of blood in the blood vessel of interest, iv) calculate the three dimensional position of the highest Doppler energy from the blood flow in the vessel of interest; and v) repeat steps (i) through (iv) to generate a plurality of calculated three dimensional positions; vi) generate a three dimensional image of the blood vessel of interest from the plurality of calculated three dimensional positions; and (e) displaying the three dimensional image on a display monitor that is electrically connected to the processor. Optionally, the three dimensional image can be of a particular region of a blood vessel of interest. Moreover, a processor of a method described herein can also determine at least one additional beam having an angle between the azimuth difference beam and the elevation difference beam prior to modulating the directions of the transmitted and received sonic energy, and the at least one additional beam is also used to modulate the directions of the transmitted and received sonic energy, and calculate the three dimensional position of the highest Doppler energy. Angles for use with the at least one additional beam are described above. Moreover, in another embodiment of the present invention, the distance between the elements of the array is greater than ½ the wavelength of the sonic energy generated by the at least one element. Furthermore, the present invention extends to a device generating a three dimensional image of a blood vessel of interest in a subject using sonic energy, comprising: a) an array of sonic transducer elements, wherein the element spacing in the array is greater than, equal or less than a half wavelength of the sonic energy produced by the elements, and at least one element transmits sonic energy, and a portion of the elements receive sonic energy; b) a processor electrically connected to the array so that echoes received from a volume of the subject's body having the blood vessel of interest due to directing sonic energy produced by the at least one element of the array into the subject's body is reported to the processor, wherein the processor is programmed to: i) Doppler process the echoes to determine radial velocity of the blood flowing in the blood vessel of interest; ii) calculate a three dimensional position of blood flow in the blood vessel of interest; iii) repeat steps (i) through (ii) to generate a plurality of calculated three dimensional positions; v) generate a three dimensional image from the plurality of calculated three dimensional positions, and (c) a display monitor that is electrically connected to the processor which displays the three dimensional image. As explained above, a device of the present invention permits an operator to generate and display three dimensional images of a blood vessel of interest, and even of a particular region of a blood vessel that the operator wants to investigate closely. Moreover, in a particular embodiment, a processor of a device of the present invention can be programmed to calculate the three dimensional position of a blood vessel by i) determining a sum beam, an azimuth difference beam and an elevation difference beam from the echoes received from the blood vessel of interest after Doppler processing the echoes; ii) modulating the directions of the transmitted and received sonic energy based upon the sum, azimuth difference and elevation difference beams in order to lock on to the highest Doppler energy calculated from echoes from the flow of blood in the blood vessel of interest, iii) calculating the three dimensional position of the highest Doppler energy from the blood flow in the vessel of interest; and iv) repeat steps (I) through (iii) in order to generate a plurality of calculated three dimensional positions used to generate the three dimensional image. Optionally, the processor can be programmed to further determine at least one additional beam having an angle between the azimuth difference beam and the elevation difference beam prior to modulating the directions of the transmitted and received sonic energy, wherein the at least one additional beam is used to modulate the directions of the transmitted and received sonic energy. The angle between the azimuth difference beam and the elevation difference beam of the additional beam can vary. In a particular embodiment, the at least one additional beam is at an angle that is orthogonal to the blood vessel of interest. Furthermore, the present invention extends to a thinned array for use in an ultrasound device, comprising a plurality of sonic transducer elements, wherein the element spacing in the array is greater than a half wavelength of the sonic energy produced by the elements, and the elements are positioned and sized within the array, and sonic energy is electronically steered by the elements so that any grating lobes produced by the sonic energy are suppressed. In a particular embodiment, the elements positioned and sized so that they are flush against each other. Hence, the current invention performs blood velocity monitoring by collecting Doppler data in three dimensions; azimuth, elevation, and range (depth); so that the point (in three dimensional space) at which the velocity is to be monitored can be acquired and tracked when the patient or the sensor moves. The invention also produces a three dimensional map of the blood flow and converts measured radial velocity to true vector velocity. Moreover, in this invention, once the desired signal is found, it will be precisely located and continually tracked with accuracy far better than the resolution. A heretofore unknown method to achieve sub-resolution tracking and mapping involves a novel and unobvious extension of a procedure called “monopulse”. Monopulse tracking has been used in military applications for precisely locating and tracking a point target with electromagnetic radiation. However, it has never been utilized in connection with sonic waves to determine the velocity of moving fluids in vivo. This invention provides: (1) affordable three-dimensional imaging of blood flow using a low-profile easily-attached transducer pad, (2) real-time vector velocity, and (3) long-term unattended Doppler-ultrasound monitoring in spite of motion of the patient or pad. None of these three features are possible with current ultrasound equipment or technology. The pad and associated processor collects and Doppler processes ultrasound blood velocity data in a three-dimensional region through the use of a two-dimensional phased array of piezoelectric elements on a planar, cylindrical, or spherical surface. Through use of unique beamforming and tracking techniques, the invention locks onto and tracks the points in three-dimensional space that produce the locally maximum blood velocity signals. The integrated coordinates of points acquired by the accurate tracking process is used to form a three-dimensional map of blood vessels and provide a display that can be used to select multiple points of interest for expanded data collection and for long term continuous and unattended blood flow monitoring. The three dimensional map allows for the calculation of vector velocity from measured radial Doppler. In a particular embodiment, a thinned array (greater than half-wavelength element spacing of the transducer array) is used to make a device of the present invention inexpensive and allow the pad to have a low profile (fewer connecting cables for a given spatial resolution). The array is thinned without reducing the receiver area by limiting the angular field of view. The special 2-D phased array used in this invention makes blood velocity monitoring inexpensive and practical by (1) forming the beams needed for tracking and for re-acquiring the blood velocity signal and by (2) allowing for an element placement that is significantly coarser than normal half-wavelength element spacing. The limited range of angles that the array must search allows for much less than the normal half wavelength spacing without reducing the total receiver area. Grating lobes due to array thinning can be reduced by using wide bandwidth and time delay steering. The array, or at least one element of the array, is used to sequentially insonate the beam positions. Once the region of interest has been imaged and coarsely mapped, the array is focused at a particular location on a particular blood vessel for measurement and tracking. Selection of the point or points to be measured and tracked can be based on information obtained via mapping and may be user guided or fully automatic. Selection can be based, for example, on peak response within a range of Doppler frequencies at or near an approximate location. In the tracking mode a few receiver beams are formed at a time: sum, azimuth difference, elevation difference, and perhaps, additional difference beams, at angles other than azimuth (=0 degrees) and elevation (=90 degrees). Monopulse is applied at angles other than 0 and 90 degrees (for example 0, 45, 90, and 135 degrees) in order to locate a vessel in a direction perpendicular to the vessel. When the desired (i.e. peak) blood velocity signal is not in the output, this is instantly recognized (e.g., a monopulse ratio, formed after Doppler filtering, becomes non-zero) and the array is used to track (slow movement) or re-acquire (fast movement) the desired signal. Re-acquisition is achieved by returning to step one to form and Doppler-process a plurality of beams in order to select the beam (and the time delay or “range gate”) with the most high-Doppler (high blood velocity) energy. This is followed by post-Doppler monopulse tracking to lock a beam and range gate on to the exact location of the peak velocity signal. In applications such as transcranial Doppler, where angular resolution based on wavelength and aperture size is inadequate, fine mapping is achieved, for example, by post-Doppler monopulse tracking each range cell of each vessel, and recording the coordinates and monopulse-pair angle describing the location and orientation of the monopulse null. With a three-dimensional map available, true vector velocity can be computed. For accurate vector flow measurement, the monopulse difference is computed in a direction orthogonal to the vessel by digitally rotating until a line in the azimuth-elevation or C-scan display is parallel to the vessel being monitored. The aperture is more easily rotated in software (as opposed to physically rotating the transducer array) if the aperture is approximately circular (or eliptical) rather than square (or rectangular). Also, lower sidelobes result by removing elements from the four corners of a square or rectangular array in order to make the array an octagon. In this invention, as long as (1) a blood vessel or (2) a flow region of a given velocity can be resolved by finding a 3-D resolution cell through which only a single vessel passes, that vessel or flow component can then be very accurately located within the cell. Monopulse is merely an example of one way to attain such sub-resolution accuracy (SRA). Other methods involve “super-resolution” or “parametric” techniques used in “modern spectral estimation”, including the MUSIC algorithm and autoregressive modeling, for example. SRA allows an extremely accurate map of 3-D flow. Furthermore, the present invention utilizes post-Doppler, sub-resolution tracking and mapping; it does Doppler processing first and uses only high Doppler-frequency data. This results in extended targets since the active vessels approximate “lines” as opposed to “points”. In three-dimensional space, these vessels are resolved, one from another. At a particular range, the monopulse angle axis can be rotated (in the azimuth-elevation plane) so that the “line” becomes a “point” in the monopulse angle direction. That point can then be located by using super-resolution techniques or by using a simple technique such as monopulse. By making many such measurements an accurate 3-D map of the blood vessels results. Methods for extending the angular field of view of the thinned array (that is limited by grating lobes) include (1) using multiple panels of transducers with multiplexed processing channels, (2) convex V-shaped transducer panels, (3) cylindrical shaped transducer panel, (4) spherical shaped transducer panel, and (5) negative ultrasound lens. If needed, moving the probe and correlating the sub-images can create a map of an even larger region. Active digital beamforming can also be utilized, but the implementation depends on a choice to be made between wideband and narrowband implementations. If emphasis is on high resolution mapping of the blood vessels, then a wide bandwidth (e.g., 50% of the nominal frequency) is used for fine range resolution. If emphasis is on Doppler spectral analysis, measurement, and monitoring, the map is only a tool. In this case, a narrowband, low cost, low range-resolution, high sensitivity implementation might be preferred. A wideband implementation would benefit in performance (higher resolution, wider field of view, and reduced grating lobes) using time-delay steering while a narrowband implementation would benefit in cost using phase-shift steering. The invention can thus be described in terms of two preferred implementations. In a wideband implementation, time delay steering can be implemented digitally for both transmit and receive by over-sampling and digitally delaying in discrete sample intervals. In a narrowband implementation, (1) phase steering can be implemented digitally (digital beamforming) for both transmit and receive, and (2) bandpass sampling (sampling at a rate lower than the signal frequency) can be employed with digital down-conversion and filtering. Accordingly, it is an object of the present invention to locate the point in three dimensional space having the greatest high-Doppler energy, and determining coordinates for that point. With that information, and the radial velocity of the blood flowing through the blood vessel at that point, a variety of blood flow parameters can be calculated at that point, including, but not limited to vector velocity of blood flow, volume of blood flow, or Doppler spectral distribution. The parameter being measured can be an instantaneous value, or an average value determined over a heart cycle. It is also an object of the present invention to continuously track and map in vivo the point in three dimensional space having the greatest Doppler-energy, and using the coordinates to generate a three dimensional image of a blood vessel and blood flow therein that possess a much greater resolution than images generated using heretofore known Doppler ultrasound methods and devices. It is yet another object of the present invention to provide a thinned array which does not utilize the number of element transducers as are required with heretofore known Doppler ultrasound devices. As a result, the decreased number of elements in the array decreases size of the array utilized and provides a patient being analyzed with mobility that would not be available if using conventional ultrasound devices to obtain blood flow parameters such as vector velocity, blood flow volume, and Doppler spectral distribution. The parameter being measured can be an instantaneous value, or an average value determined over a heart cycle. These and other aspects of the present invention will be better appreciated by reference to the following drawings and Detailed Description. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates the Blood Flow Mapping Monitor in use with a Transcranial Doppler Probe, as an example. FIG. 2 shows a 64-element bistatic ultrasound transducer array example, where, with D=2d, the same elements are reconfigured differently for transmit and receive during the acquisition phase of operation. FIG. 2(a) shows the Receive Configuration, where all 64 elements receive at once. FIG. 2(b) shows the Transmit Configuration, where, during acquisition, the 16 sub-apertures transmit one at a time. FIG. 3 is an example overall block diagram of a blood flow mapping monitor embodiment. FIG. 4 illustrates ultrasound beam coverage for the TCD array example of FIG. 2. The left illustration shows 25 digitally beam-formed beams, as an example. On the right, is shown, for that example, the manner in which the transmit beam encompasses 21 receive beams in the acquisition mode. FIG. 5 shows one-dimensional patterns for a bistatic transducer array with D=2 d as in FIG. 2. FIG. 5a (top) shows the transmit element pattern. FIG. 5b shows the receive Element Pattern and Array Pattern with the receiver beam steered to broadside (x=0). The Array Pattern has Grating Lobes (Receiver Ambiguities). FIG. 5c shows the resultant two-way beam pattern (product of all three patterns above). The Grating Lobes are suppressed. FIG. 6 is the same as FIG. 5, with the receive array beam steered to x=0.2. FIG. 7 shows the Two-way pattern of a receiver beam steered to the half power point (x=0.2). This is FIG. 6c plotted in dB. FIG. 8 shows a one-dimensional representation of the example of FIG. 4. FIG. 8a shows the product of transmit and receive Element Patterns. FIG. 8b plots a set of five receive beams showing Grating Lobes of the Thinned Array. FIG. 8c plots the resultant two-way beams with Grating Lobes suppressed. FIG. 9 is a block diagram of one possible embodiment of the Transmit-Receive Electronics for a Bistatic Ultrasound Imaging Sensor and Blood Monitoring Monitor. FIG. 10 shows the receiver channel signal spectrum illustrating functions performed by the FPGA of FIG. 9 on each of the 64 received signals for a narowband case. FIG. 11 shows the geometry involved in using azimuth monopulse to more accurately determine the cross-range location of a vessel. The range resolution is better than the cross-range resolution and the measured radial velocity field or color flow map has been utilized to rotate and orient the azimuth and elevation axes so that the center of the vessel is vertical, at approximately zero azimuth. The black circular cylinder represents the location of all points within the spatial resolution cell that have a particular velocity. FIG. 12 shows the geometry involved in using Doppler ultrasound to determine the diameter of a vessel or the velocity field within the vessel. While the initial 3-D orientation of the vessel is general, a measured 3-D radial velocity field or 3-D color flow map has been utilized to rotate and orient the azimuth and elevation axes so that the center of the vessel is vertical, at approximately zero azimuth. In other words, the coordinate system has been rotated about the depth-axis so that the centerline of the vessel is in the depth-elevation plane. This can be accomplished either by a change of coordinates in software or by physically rotating the ultrasound probe. The black circular cylinder represents the location of all points within the illustrated box that have a particular velocity. The diameter of the cylinder is then measured as the azimuth extent of a high-resolution depth-azimuth or B-scan image at the Doppler frequency under examination. FIG. 13 illustrates the Blood Flow Mapping Monitor in use with a Transcranial Doppler Probe, as an example. FIG. 14 shows a 52-element ultrasound transducer array example, based on an 8 by 8 rectangular array of elements with 3 elements removed from each corner to make the array octagonal instead of rectangular or square. For this example, the elements are square (d1=d2=d) and L/d=8. FIG. 15 shows a typical pattern of electronically scanned beams produced by the array in FIG. 14. The beam width is nominally, given by the signal wavelength divided by the size, L, of the array. The angular field of view (F.O.V.) is limited by the maximum angle to which the array can be steered without producing grating lobes that are not sufficiently attenuated by the pattern of the individual d×d element. FIG. 16 shows one-dimensional patterns for an eight-element monostatic linear transducer array corresponding to a column or a row in FIG. 16. FIG. 16a (top) shows the Element Pattern and Array Pattern with the beam steered to broadside (x=0). The Array Pattern has Grating Lobes (Receiver Ambiguities). FIG. 16b shows the resultant beam pattern. The Grating Lobes are suppressed. FIG. 17 is the same as FIG. 16, with the array beam steered to an angle at which a grating lobe exceeds the highest sidelobe. The thinned array of FIG. 16 should not be steered beyond±arcsin (λ/5d) (±4.7° for the example used) if grating lobes are to be suppressed. FIG. 18 shows the pattern of a beam steered to the point where the grating lobe problem appears. This is FIG. 17b plotted in dB. FIG. 19 shows a dual 52-active-element ultrasound transducer array example (similar to that in FIG. 14) with a total of 116 elements, 52 of which are used at a time. FIG. 19B shows that the two sub-arrays are in two different planes, ilted to reduce the overlap between beams from the two sub-arrays and maximize the azimuth angular field of view. FIG. 20 shows a 52-active-element ultrasound transducer array example (similar to that in FIG. 14) with a total of 84 elements (52 of which are used at a time) and with a slightly convex cylindrical shape. The indicated L1×L2′ sub-aperture would be activated for the formation of beams pointed to one side. FIG. 21 is an example overall block diagram of a blood flow mapping monitor embodiment. FIG. 22 is a block diagram of one possible embodiment of the analog Transmit-Receive Electronics for an Ultrasound Imaging Sensor and Blood Monitor. FIG. 23 shows the geometry involved in using azimuth monopulse to more accurately determine the cross-range location of a vessel. The measured radial velocity field or color flow map has been utilized to rotate and orient the azimuth and elevation axes so that the center of the vessel is vertical, at approximately zero azimuth. The black circular cylinder represents the location of all points within the spatial resolution cell that have a particular velocity. DETAILED DESCRIPTION OF THE INVENTION The invention involves (1) a family of ultrasound sensors, (2) the interplay of a set of core technologies that are unique by themselves, and (3) a number of design options which represent different ways to implement the invention. To facilitate an organizational understanding of this many-faceted invention, a discussion of each of the three topics above follows. The sensors addressed are all two-dimensional (i.e., planar or on the surface of a convex shape such as a section of a cylinder) arrays of piezoelectric crystals for use in active, non-invasive, instantaneous (or real-time), three-dimensional imaging and monitoring of blood flow. The sensors use a unique approach to 3-D imaging of blood velocity and blood flow that (1) allows for finer image resolution than would otherwise be possible with the same hardware complexity (number of input cables and associated electronics) and (2) allows for finer accuracy than would ordinarily be possible based on the resolution. The invention measures and monitors 3-D vector velocity rather than merely the radial component of velocity. Moreover, the present invention also utilizes (1) array thinning with large elements and limited scanning, (2) array shapes to reduce peak sidelobes and extend the field of coverage, (3) post-Doppler sub-resolution tracking, (4) post-Doppler sub-resolution mapping, (5) additional methods for maximizing the angular field of view, and (6) various digital beamforming procedures for implementing the mapping, tracking, and measurement processes. The present invention also extends to array thinning, where the separation between array elements is significantly larger than half the wavelength. This reduces the number of input cables and input signals to be processed while maintaining high resolution and sensitivity and avoiding ambiguities. In a transcranial Doppler application, for example, where signal to noise and hence receiver array area is of paramount importance, array thinning is possible without reducing the receiver array area because a relatively small (compared to other applications) angular field of view is needed. Thinning with full aperture area imposes limitations on the angular field of view. Methods for expanding the field of view include using more elements than are active at any one time. For example, if the electronics are switched between two identical panels, the cross-range field of view at any depth is increased by the size of the panel. If the panels are pointed in slightly different directions so that overlapping or redundant beams are avoided, the field of view is doubled. A generalization of this approach involves the use of an array on a cylindrical or spherical surface. Once a section of a blood vessel is resolved from other vessels in Doppler, depth, and two angles (az and el), Post-Doppler sub-resolution processing locates that section to an accuracy that is one-tenth to one-twentieth of the resolution. This allows for precise tracking and accurate mapping. Tracking provides for the possibility of unattended long term monitoring and mapping aids the operator in selecting the point or points to be monitored. Furthermore, methods of the present invention permit non-invasive, continuous, unattended, volumetric, blood vessel tracking, ultrasound monitoring and diagnostic device for blood flow. It will enable unattended and continuous blood velocity measurement and monitoring as well as 3-dimensional vascular tracking and mapping using an easily attached, electronically steered, transducer probe that can be in the form of a small pad for monitoring application, when desired. Moreover, a device and method of the present invention have applications in measuring the parameters described above in any part of the body. A nonlimiting example described below involves a cranial application. However as set forth, a device and method of the present have applications in any part of the body, and can be used to track and map any blood vessel in the body. A device of the present invention can, for example: 1. Measure and continuously monitor blood velocity with a small low-profile probe that can be adhered, lightly taped, strapped, banded, or otherwise easily attached to the portion of the body where the vascular diagnosis or monitoring is required. 2. Track and maintain focus on multiple desired blood vessels in spite of movement. 3. Map 3-D blood flow; e.g., in the Circle of Willis (the central network of arteries that feeds the brain) or other critical vessels in the cranial volume. 4. Perform color velocity imaging and display a 3-D image of blood flow that is rotated via track ball or joystick until a desired view is selected. 5. Form and display a choice of projection, slice, or perspective views, including (1) a projection on a depth-azimuth plane, a B-scan, or a downward-looking perspective, (2) a projection on an azimuth-elevation plane, a C-scan, or a forward-looking perspective, or (3) a projection on an arbitrary plane, an arbitrary slice, or an arbitrary perspective. 6. Use a track ball and buttons to position circle markers on the points were measurement or monitoring of vector velocity is desired. 7. Move the track location along the blood vessel by using the track ball to slide the circle marker along the image of the vessel. 8. Display actual instantaneous and/or average vector velocity and/or estimated average volume flow. 9. Maintain a multi-day history and display average blood velocity versus time for each monitored vessel over many hours. 10. Sound an alarm when maximum or minimum velocity is exceeded or when emboli count is high; and maintain a log of emboli detected. 11. Track, map, and monitor small vessels (e.g., 1 mm in diameter), resolve vessels as close as 4 mm apart (for example), and locate them with an accuracy of ±0.1 mm, for example. Moreover, as explained herein, numerous methods have applications in obtaining the three dimensional coordinates of points along a blood vessel from echoes returned from the body, and are encompassed by the present invention. A particular nonlimiting example of such a method having applications herein is a novel and unobvious variation of monopulse tracking. For tracking purposes utilizing monopulse, up to nine beams are simultaneously formed for each transmit beam position. In addition to the “sum” beam that corresponds to the transmitted beam, there will either be 4 monopulse difference beams or there will be 8 overlapping focused beams. If a cluster of eight focused beams is used, these will be highly overlapped with the sum beam, and displaced very slightly from the sum beam, with their centers equally spaced on a small circle around the center of the sum beam. These satellite beams would then operate in pairs to form four difference beams. For example, the azimuth Monopulse ratio can be produced in two different ways, which will call “liner” and “non-linear”. The non-linear method will determine the magnitudes or the powers of three received signals, left, right, and sum (L, R, and S), and compute Ma=(|L|−|R|)/|S|. The linear method uses complex signals and computes the azimuth monopulse ratio as the real part of the ratio Da/S, where Da=L−R. Da is the azimuth difference. For an ideal point target, the linear method for computing Ma results in an excellent estimate of the azimuth angle error. It also has the advantage of only requiring 4, instead of 8 auxiliary beams. These 4 beams would be an azimuth difference beam, Da, an elevation difference beam, and two diagonal difference beams. The individual beams, such as L and R, are not needed. However, beam shapes will be highly distorted by refraction through bone and tissue, and a “sub-optimum” non-linear approach might be more robust. Regardless of which monopulse method is used, the conventional two difference beams used in radar (azimuth difference and elevation difference) may not be enough. The projection of the high-velocity data on a plane perpendicular to the transducer line of sight (the C-scan) will usually be a line, not a point. With multiple difference beams, equally spaced in angle, one will be approximately perpendicular to the C-scan projection of the vessel. The system will select the monopulse difference output with the largest magnitude. This provides an approximate orientation of the C-scan projection of the vessel. The corresponding monopulse ratio (provided the sum beam power exceeds a threshold) is used to correctly re-steer and maintain a beam precisely centered on that vessel. If the power map output of a Wall filter is used for the monopulse beams, the beam outputs are power and hence a complex ratio is not available. In that case the nonlinear method would be used. An alternative is to use the complex wall filter output, before computing the power, with the linear method. During measurement, however, the output of a particular (high velocity) FFT Doppler bin may be used for monopulse (provided that the magnitude or power of he sum beam at that Doppler exceeds a threshold). In that case either the linear or the nonlinear monopulse ratio may be used. Another alternative is to use FFT processing and form the monopulse ratio (linearly or non-linearly) at the output of a high-velocity Doppler-frequency cell with high sum-beam power. For example, set a power threshold and select the highest (positive or negative) velocity cell with power that exceeds the threshold. Since the data in a single FFT cell is expected to be noisy, this procedure is recommended for a measurement dwell, where enough time is spent in a single beam position to have both useable velocity resolution and the ability to make several measurements (multiple FFTs per frame). FFT-Based Monopulse and Monopulse Averaging During Measurement In a K pulse dwell, let K=K1×K2, where K1 is the number of input pulses used in the FFT and K2 is the number of FFT's. Instead of performing monopulse to re-steer the beam every K, pulses, we compute the monopulse ratio at the output of a desired high velocity Doppler bin, and average its value over K2 FFT's. This reduces the steering noise while assuring that we are locating the center of the vessel (the highest Doppler Energy). We chose the highest Doppler frequency for which the minimum sum beam power exceeds a threshold, and utilize only that Doppler cell for monopulse. The average is best performed as a weighted average. For example, if Dn and Sn are (say, elevation) difference-beam and sum beam outputs in the nth FFT for the selected Doppler bin, we chose: M = ∑ n = 1 K 2 S n 2 M n ∑ n = 1 K 2 S n 2 , where M n = Re { D n / S n } or M n = D n 2 S n 2 depending on whether linear or non-linear monopulse is used. For linear monopulse it might be best to use only one large FFT (K2=1). For non-linear monopulse, the expression simplifies to: M = ∑ n = 1 K 2 D n 2 ∑ n = 1 K 2 S n 2 [Note that because a ratio is involved (so that beam pointing error is not confused with signal strength) even the “linear” method is non-linear.] A device of the present invention will allow a person with little training to apply the sensor and position it based on an easily understood ultrasound image display. The unique sensor can continuously monitor artery blood velocity and volume flow for early detection of critical events. It will have an extremely low profile for easy attachment, and can track selected vessels; e.g., the middle cerebral artery (MCA), with no moving parts. If the sensor is pointed to the general volume location of the desired blood vessel (e.g., within ±1 cm.), it will lock to within ±0.1 mm of the point of maximum radial component of blood flow and remain locked in spite of patient movement. A device of the present invention can remain focused on the selected blood vessels regardless of patient movement because it produces and digitally analyzes, in real time, a 5-dimensional data base composed of signal-return amplitude as a function of: 1. Depth, 2. Azimuth, 3. Elevation, 4. Radial component of blood velocity, 5. Time. Since a device of the present invention can automatically locate and lock onto the point with the maximum volume of blood having a significant radial velocity, unattended continuous blood velocity monitoring is one of its uses. By using the precise relative location of the point at which lock occurs as a function of depth, a device of the present invention can map the network of blood vessels as a 3-dimensional track without the hardware and computational complexity required to form a conventional ultrasound image. Using the radial component of velocity along with the three-dimensional blood path, a device of the present invention can directly compute vector velocity. A device used in a method of the present invention is a non-mechanical Doppler ultrasound-imaging sensor comprising probes, processing electronics, and display. Specific choices of probes allow the system to be used for transcranial Doppler (TCD), cardiac, dialysis, and other applications. The present invention may be better understood by reference to the following non-limiting Examples, which are provided as exemplary of the invention. The following Examples are presented in order to more fully illustrate particular embodiments of the invention. They should in no way be construed, however, as limiting the broad scope of the invention. EXAMPLE 1 An Ultrasound Diagnostic and Monitoring Sensor with Real-Time 3-D Mapping and Tracking of Blood Flow This embodiment of the present invention has application for medical evaluation and monitoring multiple locations in the body; however, the transcranial Doppler application will be used as an example to describe the invention. This invention provides: (1) affordable three-dimensional imaging of blood flow using a low-profile easily-attached transducer pad, (2) real-time vector velocity, and (3) long-term unattended Doppler-ultrasound monitoring in spite of motion of the patient or pad. None of these three features are possible with current ultrasound equipment or technology. The pad and associated processor collects and Doppler processes ultrasound blood velocity data in a three dimensional region through the use of a planar phased array of piezoelectric elements. Through use of unique beamforming and tracking techniques, the invention locks onto and tracks the points in three-dimensional space that produce the locally maximum blood velocity signals. The integrated coordinates of points acquired by the accurate tracking process is used to form a three-dimensional map of blood vessels and provide a display that can be used to select multiple points of interest for expanded data collection and for long term continuous and unattended blood flow monitoring. The three dimensional map allows for the calculation of vector velocity from measured radial Doppler. A thinned array (greater than half-wavelength element spacing of the transducer array) is used to make the device inexpensive and allow the pad to have a low profile (fewer connecting cables for a given spatial resolution). The same physical array can also be used to form a broad transmit beam encompassing a plurality of narrow receive beams. Initial acquisition of the blood velocity signal is attained by insonating a large region by defocusing the transmit array or by using a small transmitting sub-aperture, for example. The computer simultaneously applies numerous sets of delays and/or complex weights to the receiver elements in order to form M simultaneous beams. With M beams being formed simultaneously, the receiver can dwell M times as long, so as to obtain high S/N and fine Doppler resolution. For an embodiment that utilizes a small transmitting sub-aperture, the source of the transmitted energy within the array (i.e., the location of the transmitter sub-aperture) varies with time in order to lower the temporal average spatial peak intensity to prevent skin heating. The array is thinned without reducing the receiver area by limiting the angular field of view. When needed, a map of a larger region is created by moving the probe and correlating the sub-images. Once the region of interest has been imaged and coarsely mapped, the full transmitter array is focused at a particular location on a particular blood vessel for tracking. In the tracking mode: (1) grating lobes due to array thinning are reduced by using wide bandwidth and time delay steering and (2) only three beams are formed at a time: sum, azimuth difference, and elevation difference. When the desired (i.e. peak) blood velocity signal is not in the output, this is instantly recognized (e.g., a monopulse ratio, formed after Doppler filtering, becomes non-zero) and the array is used to track (slow movement) or re-acquire (fast movement) the desired signal. Re-acquisition is achieved by returning to step one to form and Doppler-process a plurality of beams in order to select the beam (and the time delay or “range gate”) with the most high-Doppler (high blood velocity) energy. This is followed by post-Doppler monopulse tracking in azimuth, elevation, and range to lock a beam and range gate on to the exact location of the peak velocity signal. In applications such as transcranial Doppler, where angular resolution based on wavelength and aperture size is inadequate, fine mapping is achieved, for example, by post-Doppler monopulse tracking each range cell of each vessel, and recording the coordinates describing the location of the monopulse null. With a three-dimensional map available, true vector velocity can be computed. For accurate vector flow measurement, the monopulse difference is computed in a direction orthogonal to the vessel by digitally rotating until a line in the azimuth-elevation or C-scan display is parallel to the vessel being monitored. All current ultrasound devices (including “Doppler color flow mapping” systems) form images that are limited by their resolution. In some applications, such as TCD, the low frequency required for penetration makes the azimuth and elevation resolution at the depths of interest larger than the vessel diameter. In this invention, as long as (1) a blood vessel or (2) a flow region of a given velocity can be resolved by finding a 3-D resolution cell through which only a single vessel passes, that vessel or flow component can then be very accurately located within the cell. Monopulse is merely an example of one way to attain such sub-resolution accuracy (SRA). SRA allows an extremely accurate map of 3-D flow. This invention utilizes post-Doppler, sub-resolution tracking and mapping; it does Doppler processing first and uses only high Doppler-frequency data. This results in extended targets since the active vessels approximate “lines” as opposed to “points”. In three-dimensional space, these vessels are resolved, one from another. At a particular range, the azimuth-elevation axis can be rotated so that the “line” becomes a “point” in the azimuth dimension. That point can then be located by using super-resolution techniques or by using a simple technique such as monopulse. Overview of the Embodiment The invention is complex because it involves (1) a family of ultrasound sensors (for different parts of the body), (2) the interplay of a set of core technologies that are unique by themselves, and (3) a number of design options which represent different ways to implement the invention. To facilitate an organizational understanding of this many-faceted invention, we precede a description of an overall preferred embodiment with a discussion of each of the three topics above. The sensors addressed are all two-dimensional (i.e., planar) arrays of piezoelectric crystals for use in active, non-invasive, instantaneous (or real-time), three-dimensional imaging and monitoring of blood flow. While the sensors and the techniques for their use apply to all blood vessels in the body, the figures and detailed description emphasizes the transcranial Doppler (TCD) monitor because that application is most difficult to implement without all of the components of this invention. The sensors use a unique approach to 3-D imaging of blood velocity and blood flow that (1) allows for finer image resolution than would otherwise be possible with the same hardware complexity (number of input cables and associated electronics) and. (2) allows for finer accuracy than would ordinarily be possible based on the resolution. The invention measures and monitors 3-D vector velocity rather than merely the radial component of velocity. The core technologies that constitute the invention are (1) array thinning with suppression of ambiguities or grating lobes, (2) post-Doppler sub-resolution tracking, and (3) post-Doppler sub-resolution mapping. The invention encompasses two ways to thin the array (reducing the number of input cables and input signals to be processed while maintaining high resolution and avoiding ambiguities). The first is bistatic operation; the second is broadband operation. In the TCD application, where signal to noise and hence receiver array area is of paramount importance, array thinning is possible without reducing the receiver array area because a relatively small (compared to other applications) angular field of view is needed. One particular bistatic approach to thinning reduces transmitter area and consequently poses a problem of excessive spatial peak intensity (skin heating) in the TCD application. This is solved by a component invention called transmitter diversity (which lowers the temporal average of the spatial peak intensity). The phase-defocusing bistatic approach and the monostatic or bistatic broadband approach to thinning all use the entire aperture and hence do not require transmitter diversity. In the TCD application, the achievable angular resolution is poor, regardless of the method of thinning, or whether or not thinning is used. Once a section of a blood vessel is resolved from other vessels in Doppler, depth, and two angles (az and el), Post-Doppler sub-resolution processing locates that section to an accuracy that is 10 to 20 times as fine as the resolution. This allows for precise tracking and accurate mapping. Tracking provides for the possibility of unattended long term monitoring and mapping aids the operator in selecting the point or points to be monitored. There are many options available in the design of any member of the family of sensors that utilizes any or all of the core technologies that comprise this invention. A two-dimensional array is established art that can be designed in many ways and can have many sizes and shapes (rectangular, round, etc.). Digital beamforming (DBF) is a technique that has been in the engineering literature (especially radar and sonar) for many years. One medical ultrasound DBF patent cites many references, while another describes a particular instance of DBF without citing the other patent or any other prior art. While planar arrays, DBF, Doppler ultrasound, and color flow imaging are prior art, the manner in this specification of using such established technologies to map, track, measure, and monitor blood flow is unique. The embodiment is a non-invasive, continuous, unattended, volumetric, blood vessel tracking, ultrasound monitoring and diagnostic device. It will enable unattended and continuous blood velocity measurement and monitoring as well as 3-dimensional vascular tracking and mapping using an easily attached, electronically steered, transducer probe that can be in the form of a small pad for monitoring application, when desired. Although the device has application to multiple body parts, the cranial application will be used as a specific example. The device can, for example: 1. Measure and continuously monitor blood velocity with a small low-profile probe that can be adhered, lightly taped, strapped, banded, or otherwise easily attached to the portion of the body where the vascular diagnosis or monitoring is required. 2. Track and maintain focus on up to four desired blood vessels in spite of movement. 3. Map 3-D blood flow; e.g., in the Circle of Willis (the central network of arteries that feeds the brain). 4. Perform color velocity imaging and display a 3-D image of blood flow that is rotated via track ball or joystick until a desired view is selected. 5. Form and display a choice of projection, slice, or perspective views, including (1) a projection on a depth-azimuth plane, a B-scan, or a downward-looking perspective, (2) a projection on an azimuth-elevation plane, a C-scan, or a forward-looking perspective, or (3) a projection on an arbitrary plane, an arbitrary slice, or an arbitrary perspective. 6. Use a track ball and buttons to position circle markers on the points at which we wish to measure and monitor vector velocity. 7. Move the spatial resolution cell being measured along the blood vessel by using the track ball to slide the circle marker along the image of the vessel. 8. Display actual instantaneous and/or average vector velocity and/or estimated average volume flow. 9. Maintain a 3-day history and display average blood velocity versus time for each monitored vessel over 14 hours. 10. Sound an alarm when maximum or minimum velocity is exceeded or when emboli count is high. 11. Track, map, and monitor vessels as small as 1 mm in diameter, resolve vessels as close as 4 mm apart (for example), and locate them with an accuracy of ±0.1 mm. The Monitoring Device will allow a person with little training to apply the sensor and position it based on an easily understood ultrasound image display. The unique sensor can continuously monitor artery blood velocity and volume flow for early detection of critical events. It will have an extremely low profile for easy attachment, and can track selected vessels; e.g., the middle cerebral artery (MCA), with no moving parts. If the sensor is pointed to the general volume location of the desired artery (e.g., within ±0.5 cm.), it will lock to within ±0.1 mm of the point of maximum radial blood flow and remain locked in spite of patient movement. The device can remain focused on the selected blood vessels regardless of patient movement because it produces and digitally analyzes, in real time, a 5-dimensional data base composed of signal-return amplitude as a function of: 6. Depth, 2. Azimuth, 3. Elevation, 4. Radial blood velocity, 5. Time. Since the device can automatically locate and lock onto the point with the maximum volume of blood having a significant radial velocity, unattended continuous blood velocity monitoring is one of its uses. By using the precise relative location of the point at which lock occurs as a function of depth, the device can map the network of blood vessels as a 3-dimensional track without the hardware and computational complexity required to form a conventional ultrasound image. Using radial velocity along with the three-dimensional blood path, the device can directly compute vector velocity. The proposed device is a non-mechanical Doppler ultrasound-imaging sensor consisting of probes, processing electronics, and display. Specific choices of probes allow the system to be used for transcranial Doppler (TCD), cardiac, dialysis, and other applications. FIG. 1 shows the TCD configuration and the initial definition of the display screen. The TCD system is comprised of one or two probes attached to the head with a “telephone operator's band” or a Velcro strap. The interface and processing electronics is contained within a small sized computer. A thin cable containing 64 micro coax cables attaches the probe to the electronics in the computer. When the operator positions the probe on the head the Anterior, Middle and Posterior Cerebral Arteries and the Circle of Willis are imaged on the screen along with other blood vessels. The arteries or vessels of interest are selected by viewing the image. The system locks onto the blood vessels and tracks their position electronically. A variety of selected parameters is presented on the screen; e.g., the velocity, the pulse rate, depth of region imaged, gain and power level. Using only one probe the TCD can monitor up to two arteries (vessels) at a time. Presented on the screen are dual traces, one for each artery. The blood velocity can be dynamically monitored. As shown in FIG. 1 both the current blood velocity (dark traces) and any historic trace (lighter color) can be displayed simultaneously. The average blood velocity or estimated average flow for each artery is displayed below the respective velocity trace. The image shows the arteries and the channel used for each artery. When two probes are used, the display is split showing signals from both of them. Using a different probe (i.e., different size) with the same electronics and display, the unit can be used to measure and monitor the blood flow in a carotid artery. Similarly, it can be used to perform this function for dialysis, anesthesia, and in other procedures. The sensor is a two dimensional array of transducer elements (piezoelectric crystals) that are configured and utilized differently for transmit and receive during acquisition. For example, if a square (NxN) array is used, all N2 elements would receive at the same time, but only a 2×2 sub-aperture would transmit at any one time. This is illustrated in FIG. 2 for the case of N=8. The array need not be square. Any M×N array may be utilized in this manner. All NM received signals (64 in our example) are sampled, digitized, and processed. This can be done, for example, in a desk top or lap top personal computer with additional cards for electronics and real-time signal processing as illustrated in FIG. 1 and FIG. 3. If the PCI bus in FIG. 2 becomes a bottleneck for high speed processing, a pipelined or systolic architecture would be used. Alternatively, the processing can be performed in an application specific integrated circuit (ASIC). The small (4 element) transmit sub-aperture (FIG. 2b) produces a broad transmit beam that insonates a region containing many receive beams. This is schematically illustrated in FIG. 4 for the particular case of a square array and square elements such as in FIG. 2. Since data is received from each element of the array, this data can be combined in a processor (FIG. 3, for example) in many different ways to form any number of beams. The transmitter is larger than a single array element so that it can provide some selectivity and not insonate the grating lobes caused by array thinning (spacing the array elements more than ½ wavelength apart). The concept is illustrated below for a 1-dimensional array forming a beam that measures only one angle. For a two-dimensional array, this represents a horizontal or vertical cut through the cluster of beams shown in FIG. 4. FIG. 4 was an approximate and conceptual representation of the two-angle (azimuth and elevation) extension of the single angle case detailed below. “Grating lobes” are ambiguities or extra, unwanted, beams caused by using a transducer array whose elements are too large and hence too far apart. The following analysis illustrates grating lobe suppression for the worst case of narrowband signals and phase-shift beam processing. Time delay processing using wideband signals would be similar, but would further attenuate or eliminate grating lobes, resulting in even better performance. The next four figures show beam pattern amplitudes plotted against x=(d/λ)sin θ, (1) where x represents a normalization for the angle, θ, from which reflected acoustic energy arrives. The azimuth (or elevation) angle, θ, is zero in the broadside direction, perpendicular to the transducer array. The width (or length) of a transmitter is 2d, where d is the width (or length) of a single element of the receiver array. The wavelength of the radiated acoustic wave is λ=c/f, where c is the acoustic propagation velocity (1540 meters/second in soft tissue) and f is the acoustic frequency (usually between 1 and 10 megahertz). FIG. 5a shows the transmitter pattern aT(x)=sin 2πx/2πx (2) for the special case of uniform insonation over the 2d-wide transmitter sub-aperture being used. The receiver pattern is the product of the receiver element pattern and the receiver array pattern aR(x)=aRE(x)aRA(x) (3) Each of these two component patterns is plotted separately in FIG. 5b. Again assuming the special case of a uniform receiver element (and a square element in the case of a 2-D array), the receive element pattern is aRE(x)=sin πx/πx. (4) The receiver element pattern is twice as wide as the transmitter pattern because the receiver element is half as wide as the transmitter. In the far-field, i.e., for Ar>>L2, where r is the range or depth and L is the length of the aperture, the receive array pattern steered to the angle θ=θ0 is a RA ( x ) = ∑ n = 0 N - 1 w n ⅇ j2π n ( x - x 0 ) , ( 5 ) where wn is a weighting to reduce sidelobes and N is the number of elements in one dimension. As seen in FIG. 5b, equation (5) is periodic in x. The peak at x=x0 (x0=0 in FIG. 5) is the desired beam and the others are grating lobes. In the near field, when focused at (r0,θ0), equation (5) is replaced by the slightly better general Fresnel approximation: a RA ( x , z ) = ∑ n = 0 N - 1 w n ⅇ j2π [ n ( x - x 0 ) + ( n - N - 1 2 ) 2 ( z - z 0 ) ] ( 6 ) (provided that that the range significantly exceeds the array size, r>L), where x=d sin θ/λ, as before, and z=d2 cos2 θ/λr. (7) Because the receiver aperture is sampled with a spatial period of d, the receiver array pattern will be periodic in sin θ, with a period of λ/d (equation 5). This periodicity means that the array pattern is ambiguous. When the array is pointed broadside (θ=0), it will also be pointed at the angle θ=sin−1(λ/d), for example. In terms of the normalized variable, x, the period is unity. Since |sin θ| cannot exceed 1, the variable x is confined to the interval [−d/λ, d/λ]. The conventional element spacing is d=λ/2. Thus, in a conventional phased array, x is always between −0.5 and +0.5, and hence ambiguities are not encountered. In a highly thinned array (d>λ), there will normally be ambiguities or grating lobes as illustrated in FIG. 5b. The second grating lobe, at x=2 or θ=sin−1 (2 λ/d), is not real when d does not exceed 2λ. FIG. 5c shows the two-way pattern. The gating lobe suppression, resulting from the choice of a transmitter diameter of D=2d is valid for all values of d. In a two dimensional array, the elements could be rectangular instead of square (dx×dy), and the results would still be valid. Similar results could be obtained for an array in which the elements are staggered from row to row (and/or column to column). For example, if the receiver array is a “bathroom tile” of hexagonal elements, the transmitters could be chosen as sub-arrays consisting of an element and its six surrounding neighbors. In FIG. 6 the same array is used as in FIG. 5, but the receiver element signals are combined with a phase taper that steers the beam to x=0.2. This is approximately (a little less than) the half power point, where at(x) are(x)=0.707. In FIG. 6c, we see that the grating lobes are not completely suppressed, with the largest one at x=−1+0.2=−0.8. FIG. 7 shows this in decibels. The worst-case grating lobe is attenuated by at least 25 dB, even in the stressing case of extremely narrow band operation. A Hanning window was applied to keep the sidelobes lower than the peak grating lobe. These Figures were produced in MATLAB, using the following software (m-file): x=−2:1/64:2−1/64; p=pi*x+eps; R=sin(p)./p; p=2*p; T=sin(p)./p; N=8 n=o:N−1; % xo=0; xo=0.2; % is 2-way ½ power e=exp(j*n′*2*pi*(x−xo)); w=hanning(N); % E=(1/N)*ones(1,N)*e; E=(2/N)*w′*e; subplot(311); plot(x,abs(T)); subplot(312); plot(x,[abs(R);abs(E)]); TRE=abs(T).*abs(R).*abs(E); subplot(313); plot(x,TRE); figure(2); plot(x,20*log10(TRE)); zoom on; The dimensions in FIG. 4 are representative for a transcranial Doppler application of the invention, to provide a specific example. If f=2 MHz is chosen for the center frequency, the wavelength is 0.77 mm. An 8×8 array with a width and/or length of L=1 cm, provides a one dimensional thinning ratio of 2 d/λ=3.247. For a square array, the total number of elements is reduced by a factor of (2 d/λ)2≧10 from that of a filled array. Even greater thinning ratios are possible. Even if d/λ is kept less than 2 to avoid a second grating lobe (at x=2), complexity reductions up to a factor of 16 are possible. For the 1 cm array at 2 MHz, the hyperfocal distance (where the 3 dB focal region extends to infinity) is L2/4λ=3.25 cm. Thus, a fixed focus probe suffices for this application. However, since the simultaneous formation of multiple receive beams is conveniently performed digitally, dynamic focus on receive is easily accomplished. The quadratic phase distribution across the elements required to focus in depth is simply added to the linear phase distributions required to steer the beams. FIG. 8a shows the product of the transmitter pattern (FIG. 5a or 6a) and the receiver element pattern. FIG. 8b plots the element patterns for a set of five beams steered to x=−0.2, −0.1, 0, 0.1, and 0.2. This set of five receive beams shows grating lobes of the thinned array. FIG. 8c shows the set of resulting 2-way patterns obtained by multiplying the patterns in FIG. 8b by the function plotted in FIG. 8a. Here, the grating lobes are suppressed. This represents a horizontal or vertical cut through the cluster of beams in FIG. 4. Using the configuration described above, the cluster of beams in FIGS. 4 and 8c is used to approximately locate the desired point for collecting the blood velocity signal. For example the output of each beam in the cluster would be Doppler processed by performing an FFT or equivalent transformation on a sequence of pulse retums. The pulse repetition frequency (PRF) would typically be less than or equal to 9 kHz to unambiguously achieve a depth of 8.5 cm for the TCD application. In order to obtain a velocity resolution as fine as Δν=1 cm per second (to distinguish brain death), a dwell of duration T=λ/(2 Δν)=38.5 ms, or 347 pulses at 9 kHz, is desired. For efficient FFT processing, the number of pulses used would be zero filled to a power of 2 such as 512. The example shown in FIGS. 2 through 8 was an 8 by 8 receiver array forming a 5 by 5 cluster of beams. This is an example of an approximate rule of thumb for this invention, that an N element linear array is recommended for use in producing N/2+1 beams for Neven and [N+1]/2 beams for N odd. Thus, a 16 by 10 element rectangular array would preferably b used to form a 9 by 6 cluster of beams, though the actual number of beams formed is arbitrary. This recommended number of beams is derived below. If an N elements were used to form orthogonal beams, e.g., by an N-point FFT, then there would be N beams in a 180° angular region, from −90° to +90°, corresponding to −1<u<1, where u=sin θ. In conventional phased array ultrasound, a 128 (=N) element array is used to produce 256 (=2N) lines (sequentially scanned beams) in a 90° angular region from −45° to 45°, corresponding to −0.707<u<0.707. If the array is filled, then x=u/2 (Equation 1) and 2N beams are conventionally formed in |x|<{square root}2/4. When we thin the array, we prefer to have |x|<0.2=⅕ (the 3 dB point of the curve in FIG. 7a). The number of beams in that region, for the same beam density as used in current practice, is given by Recommended No. of beams=(1/5)N÷({square root}2/4)=2{square root}2N/5≈0.5657 N. The beams are formed digitally, using software on a personal computer or using digital signal processing hardware to implement equations such as Equation 5 or 6. The electronic interface between the probe and the processor is diagrammed in FIG. 9. This figure illustrates the case of signals from 64 elements being connected to a single A/D converter, and power being applied to sets of four elements. The use of a separate A/D converter for every received channel, for example, is another possible implementation of this invention. A conventional, half-wavelength spaced, monostatic, phased array could sequentially search a region of interest, but it would require far more elements and would thus be far more costly. Using the array differently in transmit and receive, not only allows for the formation of multiple beams; it also enables the use of the angular pattern of the transmitter to suppress receiver grating lobes. This allows for a “thinned” array (elements spaced less than a half wavelength apart). Because receive beams are formed only in a limited angular region, a wide-angle receiver element pattern (which usually implies a small element) is not required. In fact, the size of the receiver element can be as large as the element spacing. Thus the receiver array is “thinned” only in the sense that the element spacing exceeds a half wavelength. Since the element size also exceeds a half wavelength, the array area is not reduced. It is thinned only in terms of number of elements, not in terms of receiver area. Consequently, there is no reduction in signal-to-noise ratio, nor a requirement for increased transmitter power. A monostatic array would transmit from the full aperture, scanning the transmitted beam over the region being examined. The “bistatic” array of this invention transmits from a sub-aperture to insonate multiple receive beam positions simultaneously. Since there is an FDA limit to spatial peak, temporal average, intensity (Ispta), there may be a danger of exceeding this limit at the transducer surface, creating a danger of burning the skin. This potential danger is eliminated by using a different transmit sub-aperture for each coherent dwell or burst of pulses. This transmitter diversity technique spreads the temporal average intensity over the face of the array, reducing Ispta to what it would be if the entire array were used at once. For the particular implementation pictured in FIG. 9, an A/D converter is multiplexed amongst the 64 elements. The signal spectrum at any of these elements is centered at f0=2 MHz, as shown in FIG. 10a. This is a real signal with a spectrum that is symmetric about f=0. This analog signal is bandpass filtered (BPF) to insure that there is little power outside of a 444 kHz band centered at 2 MHz. If a 512/9=56.889 MHz A/D converter is used, each receive channel is sampled at fs=888.9 kHz, giving rise to a real sampled signal with a spectrum as shown in FIG. 10b. A processing element such as a field programmable gate array (FPGA) is used to shift the frequency by fs/4 (FIG. 10c) by “multiplying” by quarter cycle samples of sinusoids (which are zeros and ones). The same FPGA also digitally filters (or Hilbert transforms) the complex signal to decimate its sampling rate by a factor of two. The spectrum of the decimated digital low-pass signal is shown in FIG. 10d. The signal sent to the processor from each element has the spectrum shown in FIG. 9d, and consists of r=fs/2 complex samples per second. The total data rate into the processor is approximately 57 megabytes per second. For non-real-time operation, tens of seconds of data at a time will be collected in system memory and then transferred to hard disk. For real-time monopulse tracking, only three beams are formed, so that the data rate is reduced to 3×0.8889=2.67 Mbytes, or 5.33 Mbytes allowing for bit growth. The transmitted pulses are sent to a group of four elements. The particular embodiment shown in FIG. 9 uses diodes to block the received signals and prevent mutual coupling between the four receive elements. After a coherent pulse train (or pulse burst used for Doppler processing), the waveform is switched to another set of 4 elements for the next burst. A separate power amplifier is associated with each of the 16 sets of elements so that the switching can be accomplished at low power. One embodiment of sub-resolution tracking (i.e., tracking and locating blood flow to a small fraction of a spatial resolution cell) is “Monopulse”. Monopulse tracking is performed as follows. A particular set of complex weights are applied to the set of received signals (64 in the example of FIG. 2) to steer a beam at the middle cerebral artery, for example. The phase taper across the array defines the steering direction and the amplitude taper (called a window in radar and a shading in sonar) is used to provide low sidelobes for high dynamic range. The beam output (a linear combination of the signals) is range gated (time delay corresponding to the desired depth) and the range-gated/beam-formed output from a sequence of transmitted pulses is then Fourier transformed to obtain a plot of amplitude versus Doppler frequency. The receive beam is steered digitally to the point that produces the maximum amplitude at high Doppler frequencies. Since the measured data at each element is stored, the digital processor can apply more than one set of weights at a time, forming more than one beam. For software monopulse the processor will form three beams, all in the same direction. All three beams may have the same phases applied to the element signals; but the amplitudes will differ. The beam called Sum has all positive amplitudes, with the larger weights applied to the central elements. This forms a fairly broad beam. The beam called Az for “azimuth difference beam” has large positive weights on the rightmost elements and large negative weights on the leftmost elements (or vice versa). The beam called El for elevation difference has large positive weights on the top-most elements and large negative weights on the bottom-most elements. A correctly pointed beam would have Az=El=0, and Sum would be maximized. The ratio of the peak Doppler amplitude outputs: Az/Sum, is a precise measure of the azimuth pointing error and the corresponding ratio El/Sum measures the elevation pointing error. The digital steering phase taper is thus corrected with data from a single burst of pulses. The duration of the pulse burst is the reciprocal of the medically required Doppler resolution (usually corresponding to the minimum blood velocity that can support life). Without techniques such as those described in this specification, a sequence of at least four additional Doppler dwells or pulse bursts would be required (above, below, to the right, and to the left) in a hunt and seek method to find the correct (maximum peak Doppler Amplitude) beam. With monopulse, the correction is very precise (to within ±0.1 mm of the point of maximum peak Doppler amplitude) and virtually instantaneous. For the bistatic digitally beamformed sensor, the original data exists in computer memory. Hence, whenever the Doppler processed monopulse differences are non zero, the same data set could even be re-processed to form a correctly pointed beam. A slower processor would merely process the next burst correctly. A “front view” perspective display or a C scan display (azimuth horizontal and elevation vertical) of the blood flow map at the desired range will allow someone to aim the transducer probe or pad at the desired point (highest amplitude for high Doppler), so that the desired point is initially within the center beam. The receiver array is then steered electronically so that the monopulse differences are zero and hence the central beam is precisely aimed at the desired point. Slight motions are corrected using monopulse and large motions are corrected by again forming all beams to re-acquire the peak signal. All corrections are made entirely electronically, in the data processing or digital beamforming. A narrow receiver beam will always be precisely pointed (to within a tenth or 20th of the receiver beamwidth) as long as the desired point remains within the much larger region covered by the transmitter (FIG. 4). True vector velocity is computed from the blood vessel map and the radial velocity measured from the pulse Doppler dwell. A map, far more accurate than that attainable with the available angular resolution is attained as follows. The low-resolution map is used to locate a vessel of interest and a beam is locked on it at a fixed range, using azimuth and elevation monopulse. The coordinates of the point at which lock occurs is recorded. The range is then changed slightly, another lock (on the same vessel) is obtained, and the coordinates are recorded. In this manner, the vessel is mapped far more accurately than would be predicted from the available image resolution. All vessels within the field of view of the probe are similarly mapped. By moving the probe angle slightly, another region can be mapped in the same manner. Several such maps can be correlated over the region of pair-wise overlap and converted to a common coordinate system. In this manner a larger region is mapped and displayed than that of the current field of view. The current field of view would be highlighted, outlined, or presented as a color flow map. Points to be monitored in the current field are then selected by moving a cursor along the display (point and click). The selected points are Doppler processed and tracked using three-dimensional monopulse. While Doppler measurements provide only the radial component of velocity, the accurate blood vessel map provides the exact three-dimensional orientation of the vessel at the point being monitored. The measured radial velocity is divided by the projection of a unit vector representing the vessel at the monitored point onto the transducer line of sight. This gives the magnitude of the true vector blood velocity. Sub-resolution mapping accuracy is attainable if (1) the range-azimuth-elevation-Doppler resolution cell being examined encompasses only a single blood vessel, and (2) “azimuth” monopulse is performed with the usually vertical e-axis tilted so that the orientation of the vessel in the spatial resolution cell being processed is parallel to the e-r plane (“azimuth” is constant). The user will ascertain from the display, that the resolution cell being monitored contains only a single vessel, and would rotate the 3-D blood-vessel map to a C-scan aspect (elevation up and azimuth to the right). A vertical mark will appear in the display, within the resolution circle, to signify the orientation of the monopulse axis. This axis (parallel to the line separating the positively and negatively weighted array elements) can then be oriented SO that the mark is aligned with the blood vessel in either of two ways. The probe can be physically twisted (rotated about the line of sight), or it can be electronically rotated via digital processing because the weights are applied digitally. FIG. 11 illustrates the segment of a vessel in a single resolution cell, after rotation. The resolution cell shown is not a cube because the range resolution will typically be finer than the cross-range resolution. The illustrated circular cylinder represents blood cells in a vessel reflecting energy at a fixed Doppler frequency. These represent a cylindrical annulus of blood cells, at a constant distance from the vessel wall, moving with approximately the same velocity. In the single resolution cell of FIG. 11, the return at the highest Doppler would represent a line in three-dimensional space (the axis of the vessel) and hence a point on the azimuth axis after rotation. When applied to the highest Doppler output, the Sum beam would have broad peak at zero azimuth (a=0) and the monopulse ratio, r=Az/Sum, will be a linear function of the azimuth angle to which the array is phase steered: r(a)=ka. This result can be attained by applying the same phase across the aperture for the Az and Sum beams, but using the derivative of the Sum beam amplitude weights with respect to x and y respectively for the Az and El aperture weights. Other Embodiments If the wide transmit beam (for search and acquisition) is created by using a quadratic phase curvature instead the scheme of FIG. 2b, transmitter diversity may not be needed. Furthermore the manner of controlling grating lobes in FIG. 1 and FIGS. 5-8 is only one of many. Using a wider bandwidth and time-delay steering can also reduce grating lobes. EXAMPLE II Ultrasound Measurement of Blood Volume Flow As explained above, current ultrasound Doppler devices measure radial velocity. Several methods now exist for 3-D ultrasound imaging, such as those involving transducer motion. A three-dimensional image with Doppler allows for the measurement of vector velocity. Example I above provides measurement and long term monitoring of three-dimensional vector velocity. If the resolution of a color flow Doppler image is sufficient to provide an estimate of the inside diameter of the blood vessel, then measurement of volume blood flow becomes practical. Presently available ultrasound imaging devices have either low resolution or they only produce a two-dimensional image. The present invention combines vector velocity information (such as attained as explained in Example I above) with additional information to obtain volume flow. The additional information is the inside diameter of the vessel under examination, the blood velocity profile across the vessel, or the vector velocity as a function of time and position (i.e., the velocity field). This additional information can be obtained from a high-resolution radial-Doppler or color flow image or from external data such as a high-resolution MRI image. A two-dimensional array of piezoelectric elements, or some other means, is used to image blood flow in a three dimensional region. A particular point on a particular vessel is selected and the vector representing the orientation of the vessel is noted. The radial velocity divided by the cosine of the angle made by the vessel with the line of sight at the measurement point is the magnitude of the vector velocity. That number integrated over the vessel cross section would give the volume flow in volume per unit time or milliliters per minute, for example. FIG. 12 shows a circular cylinder representing blood cells in a vessel moving at a particular velocity and thus reflecting energy at a specific Doppler frequency. The figure assumes that methods such as those in the referenced invention, for example, have been used to measure the 3-D orientation of the vessel so that the vector velocity can be calculated and the azimuth axis can be defined to be perpendicular to the vessel. The simplest way to estimate volume flow is to measure the vessel diameter, d, (or radius d/2), calculate the cross-sectional area, A=π(d/2)2, and multiply by the average velocity. A more accurate way is to integrate the velocity as a function of posibon, over the cross-section. The velocity is a function of the radius, a, of the cylinder depicted in FIG. 12. If a is the distance from the cylinder to its axis, and v (a) is the velocity function, then the volume flow is 2 π ∫ 0 d / 2 av ( a ) ⅆ a ( 7 ) Equation (1) assumes a circular cross-section of constant radius, r=d/2. It is a special case of the more general polar coordinate integration: ∫ 0 2 π ( ∫ 0 r ( θ ) av ( a , θ ) ⅆ a ) ⅆ θ ( 8 ) The velocity function is determined by determining the diameter (and hence the radius) of the cylinder corresponding to each velocity. For example, a 1.5-cm diameter Doppler ultrasound transducer array operating at 10 MHz will be oriented with the length or azimuth direction perpendicular to the vessel to produce a B-scan (depth-azimuth) image. At a depth of approximately 10 mm, the cross range resolution is 0.1 mm. If the vessel diameter is 1 mm, the diameter can be measured with an accuracy of ±5%. The area of the vessel is thus known to an accuracy of 10%. Since the average vector velocity can be measured extremely accurately, the volume flow is also accurate to ±10%. The best accuracy is attained by measuring the azimuth extent corresponding to various velocities and then numerically evaluating equation (7) or (8). Naturally, a skilled artisan can readily program a processor to solve these equations, and calculate blood flow volume using routine programming techniques. Since the autocorrelation function (pulse-to-pulse, at a fixed range) and the Doppler Power Spectrum form a Fourier pair, the total power can be obtained either as the autocorrelation function at zero lag or the integral of the Doppler Power Spectrum (Spectral Density) over all Doppler frequencies. Since radial velocity is proportional to Doppler frequency, the mean velocity can be obtained from the autocorrelation function as shown below: R xx ( τ ) = 1 2 π ∫ - ∞ ∞ S ( ω ) ⅇ j ωτ ⅆ ω = ∫ - ∞ ∞ S d ( f ) ⅇ j 2 π f τ ⅆ f , hence R xx ( 0 ) = ∫ - ∞ ∞ S d ( f ) ⅆ f = P d = total Doppler power and R xx ( τ ) = R . xx ( τ ) = ∫ - ∞ ∞ [ j2π f S d ( f ) ] ⅇ j2π f τ ⅆ f , leading to R . xx ( 0 ) = j ∫ - ∞ ∞ 2 π f S d ( f ) ⅆ f . Thus - j R . xx ( 0 ) R xx ( 0 ) = 2 π ∫ - ∞ ∞ f S d ( f ) ∫ - ∞ ∞ S d ( f ) ⅆ f df = 2 πE { f d } , where the Doppler frequency and its mean (expected value) are related to the radial blood velocity and its mean by f d = 2 f 0 c v . Hence E { v } = ∫ - ∞ ∞ v P ( v ) ∫ - ∞ ∞ P ( v ) ⅆ v ⅆ v = - j c 4 πf 0 R . xx ( 0 s ) R xx ( 0 ) which is used in the autocorrelation method of color-flow blood-velocity imaging. We note that if we do not normalize by dividing by the total Doppler power, we obtain a power-velocity product that indicates the volume flow rate. This is due to the fact that power is directly proportional to area [see Reference 1]. Since all velocity vectors are parallel at the narrowest point (the vena contracta), flow at that particular point can be considered as non-turbulent, even though severe turbulence exists before and after. Reference 1 shows that regurgitant blood flow through the mitral heart valve can be quantitatively measured by observing the Doppler spectrum at that point and using the power-velocity-integral relation below. In terms of the velocity power spectrum, P(v)=(2f0/c) Sd(f), Reference 1 shows that the blood vessel area in a “slice” perpendicular to the line of sight is directly proportional to the total Doppler power (the total power at the output of the high-pass wall filter). A = A 0 P 0 P d = A 0 P 0 ∫ P ( v ) ⅆ v where A0 and P0 are the known area and measured power in a narrow beam, smaller than the vessel. If the blood flow makes an angle θ with the line of sight, the area, and hence power, is increased by the factor 1/cos θ. This offsets the fact that only the radial component of velocity is measured, so that the power velocity integral provides true volume flow: Q . = ⅆ Q / ⅆ t = A 0 P 0 ∫ vP ( v ) ⅆ v In Reference 1, P was measured with the same probe as P0 by masking the outside of the aperture in order to create a wider beam. With our 2-D phased array, we would merely turn off or ignore some of the outer elements. More importantly, we can use the 3-D image to precisely locate the vena contracta, and lock on to it using monopulse. We can even monitor the valve during a stress test, while the patient is on a treadmill. We note here, that there are several ways to measure the volume flow rate. Reference 1 uses the fact that it is proportional to the integral of the product of the velocity and the power per unit velocity, as in the last equation. An other way is to recognize that it is equal to the product of the average radial velocity and the total projected area that is, in turn, proportional to total Doppler power. Since the total Doppler power is used in the denominator of the autocorrelation-based color-flow velocity map, volume flow rate can be obtained by merely not dividing by the total power. If the ith pulse return (after MTI or Doppler high-pass or wall filtering) is zi=xi+jyi, i=1, 2, . . . , N, the volume flow rate is proportional to ∑ i = 2 N x i y i - 1 - y i x i - 1 The normalization (denominator) that is used to convert this last quantity to mean velocity can be ∑ i = 2 N x i x i - 1 + y i y i - 1 that is based on a derivation in Reference 2, or a simple power estimate, such as ∑ i x i 2 + y i 2 The point we wish to make here is that by not dividing by a power estimate to obtain radial velocity, we obtain volume flow. Current ultrasound Doppler imaging systems compute the mean velocity as a ratio, E(v)=F/Pd, and display it as a color flow image. Newer imaging systems [2] also display total Doppler power (at the output of the wall filter), Pd. By not dividing the color flow image by Pd, we can also display the true volume flow, dQ/dt. This is because the numerator, F=Pd·E(v), is the power-velocity-integral that is directly proportional to the volume flow. Determination of the scale factor, A0/P0=A/Pd=dQ/dt/F, that must multiply F to obtain volume flow requires further comment. A0 is the area of a reference beam. In [1], A0 is smaller than the blood flow area. We will describe three normalization approaches. 1. Use a single transmit beam, wider than the vessel, and two simultaneous receive beams. One receive beam (the measurement beam) is the same as the transmit beam and the other (the reference beam) is smaller than the vessel. 2. Use two (sequential or multiplexed) two-way (transmit and receive) beams. One (the measurement beam) is wider than the vessel and the other (the reference beam is smaller than the vessel. 3. Use two (sequential or multiplexed) two-way (transmit and receive) beams. Both are wider than the vessel and the measurement beam is wider than the reference beam. Let A0 be the known area of the reference beam, let P0 and P1 be the measured received power in the reference and measurement beams. In case 1, the transmit power density is the same for measurement and reference. The receive power is proportional to area. If the area of the vessel (in a slice perpendicular to the line of sight) is A, it follows that A/A0=P1/P0. In cases 2 and 3, the transmit power density is greater in the reference beam than in the measurement beam, but by a known factor. In all three cases, the power received in the measurement beam is proportional to the vessel area. In case 2, the received reference power also varies with vessel size, but at a different rate than in the measurement beam. With proper calibration, correct measurements can be attained in all three cases. [1]. T. Buck, Et al, “Flow Quantification in Valvular Heart Disease Based on the Integral of Backscattered Acoustic Power Using Doppler Ultrasound,” Proc. IEEE, vol.88, no.3; pp.307-330, March 2000. [2]. K. Ferrara and G DeAngelis, “Color Flow Mapping”, Uitrasound in Medicine and Biology, vol.23, no.2, pp.321-345, March 1997. EXAMPLE III 3-D Doppler Ultrasound Blood Flow Monitor with Enhanced Field and Sensitivity This example sets forth an ultrasound Doppler device and method that enables non-invasive diagnosis (the conventional role of ultrasound systems), and also non-invasive unattended and continuous monitoring of vascular blood flow for medical applications. In particular, the embodiment of the present invention set forth in this example provides: (1) affordable three-dimensional imaging of blood flow using a low-profile easily-attached transducer pad, (2) real-time vector velocity, and (3) long-term unattended Doppler-ultrasound monitoring in spite of motion of the patient or pad. None of these three features are possible with current ultrasound equipment or technology. The pad and associated processor collects and Doppler processes ultrasound blood velocity data in a three-dimensional region through the use of a two-dimensional phased array of piezoelectric elements on a planar, cylindrical, or spherical surface. Through use of unique beamforming and tracking techniques described herein, the present invention locks onto and tracks the points in three-dimensional space that produce the locally maximum blood velocity signals. The integrated coordinates of points acquired by the accurate tracking process is used to form a three-dimensional map of blood vessels and provide a display that can be used to select multiple points of interest for expanded data collection and for long term continuous and unattended blood flow monitoring. The three dimensional map allows for the calculation of vector velocity from measured radial Doppler. A thinned array (greater than half-wavelength element spacing of the transducer array) is used to make a device of the present invention inexpensive and allow the pad to have a low profile (fewer connecting cables for a given spatial resolution). The array is thinned without reducing the receiver area by limiting the angular field of view. Grating lobes due to array thinning can be reduced by using wide bandwidth and time delay steering. The array, or portions of the array, is used to sequentially insonate the beam positions. Once the region of interest has been imaged and coarsely mapped, the array is focused at a particular location on a particular blood vessel for measurement and tracking. Selection of the point or points to be measured and tracked can be based on information obtained via mapping and may be user guided or fully automatic. Selection can be based, for example, on peak response within a range of Doppler frequencies at or near an approximate location. In the tracking mode a few receiver beams are formed at a time: sum, azimuth difference, elevation difference, and perhaps, additional difference beams, at angles other than azimuth (=0 degrees) and elevation (=90 degrees). Monopulse is applied at angles other than 0 and 90 degrees (for example 0, 45, 90, and 135 degrees) in order to locate a vessel in a direction perpendicular to the vessel. When the desired (i.e. peak) blood velocity signal is not in the output, this is instantly recognized (e.g., a monopulse ratio, formed after Doppler filtering, becomes non-zero) and the array is used to track (slow movement) or re-acquire (fast movement) the desired signal. Re-acquisition is achieved by returning to step one to form and Doppler-process a plurality of beams in order to select the beam (and the time delay or “range gate”) with the most high-Doppler (high blood velocity) energy. This is followed by post-Doppler monopulse tracking to lock a beam and range gate on to the exact location of the peak velocity signal. In applications such as transcranial Doppler, where angular resolution based on wavelength and aperture size is inadequate, fine mapping is achieved, for example, by post-Doppler monopulse tracking each range cell of each vessel, and recording the coordinates and monopulse-pair angle describing the location and orientation of the monopulse null. With a three-dimensional map available, true vector velocity can be computed. For accurate vector flow measurement, the monopulse difference is computed in a direction orthogonal to the vessel by digitally rotating until a line in the azimuth-elevation or C-scan display is parallel to the vessel being monitored. The aperture is more easily rotated in software (as opposed to physically rotating the transducer array) if the aperture is approximately circular (or eliptical) rather than square (or rectangular). Also, lower sidelobes result by removing elements from the four corners of a square or rectangular array in order to make the array an octagon. All currently available ultrasound devices (including “Doppler color flow mapping” systems) form images that are limited by their resolution. In some applications, such as TCD, the low frequency required for penetration of the skull makes the azimuth and elevation resolution at the depths of interest larger than the vessel diameter. In this invention, as long as (1) a blood vessel or (2) a flow region of a given velocity can be resolved by finding a 3-D resolution cell through which only a single vessel passes, that vessel or flow component can then be very accurately located within the cell. Monopulse is merely an example of one way to attain such sub-resolution accuracy (SRA). Other methods involve “super-resolution” or “parametric” techniques used in “modem spectral estimation”, including the MUSIC algorithm and autoregressive modeling, for example. SRA allows an extremely accurate map of 3-D flow. This invention utilizes post-Doppler, sub-resolution tracking and mapping; it does Doppler processing first and uses only high Doppler-frequency data. This results in extended targets since the active vessels approximate “lines” as opposed to “points”. In three-dimensional space, these vessels are resolved, one from another. At a particular range, the monopulse angle axis can be rotated (in the azimuth-elevation plane) so that the “line” becomes a “point” in the monopuls angle direction. That point can then be located by using super-resolution techniques or by using a simple technique such as monopulse. By making many such measurements an accurate 3-D map of the blood vessels results. Methods for extending the angular field of view of the thinned array (that is limited by grating lobes) include (1) using multiple panels of transducers with multiplexed processing channels, (2) convex V-shaped transducer panels, (3) cylindrical shaped transducer panel, (4) spherical shaped transducer panel, or (5) negative ultrasound lens. If needed, moving the probe and correlating the sub-images can create a map of an even larger region. Active digital beamforming can be utilized, but the implementation depends on a choice to be made between wideband and narrowband implementations. If emphasis is on high resolution mapping of the blood vessels, then a wide bandwidth (e.g., 50% of the nominal frequency) is used for fine range resolution. If emphasis is on Doppler spectral analysis, measurement, and monitoring, the map is only a tool. In this case, a narrowband, low cost, low range-resolution, high sensitivity implementation might be preferred. A wideband implementation would benefit in performance (higher resolution, wider field of view, and reduced grating lobes) using time-delay steering while a narrowband implementation would benefit in cost using phase-shift steering. The invention can thus be described in terms of two preferred implementations. In a wideband implementation, time delay steering can be implemented digitally for both transmit and receive by over-sampling and digitally delaying in discrete sample intervals. In a narrowband implementation, (1) phase steering can be implemented digitally (digital beamforming) for both transmit and receive, and (2) bandpass sampling (sampling at a rate lower than the signal frequency) can be employed with digital down-conversion and filtering. Overview of this Embodiment. This embodiment of the present invention involves (1) a family of ultrasound sensors, (2) the interplay of a set of core technologies that are unique by themselves, and (3) a number of design options which represent different ways to implement the invention. To facilitate an organizational understanding of this many-faceted invention, a discussion of each of the three topics above follows. The sensors addressed are all two-dimensional (i.e., planar or on the surface of a convex shape such as a section of a cylinder) arrays of piezoelectric crystals for use in active, non-invasive, instantaneous (or real-time), three-dimensional imaging and monitoring of blood flow. While the sensors and the techniques for their use apply to all blood vessels in the body, the figures and detailed description emphasizes the transcranial Doppler (TCD) monitor method as a nonlimiting example. The method of the present invention utilizes a new, useful and unobvious approach to 3-D imaging of blood velocity and blood flow that (1) allows for finer image resolution than would otherwise be possible with the same hardware complexity (number of input cables and associated electronics) and (2) allows for finer accuracy than would ordinarily be possible based on the resolution. The invention measures and monitors 3-D vector velocity rather than merely the radial component of velocity. The core technologies that constitute the invention are (1) array thinning with large elements and limited scanning, (2) array shapes to reduce peak sidelobes and extend the field of coverage, (3) post-Doppler sub-resolution tracking, (4) post-Doppler sub-resolution mapping, (5) additional methods for maximizing the angular field of view, and (6) various digital beamforming procedures for implementing the mapping, tracking, and measurement processes. The invention encompasses array thinning, where the separation between array elements is significantly larger than half the wavelength. This reduces the number of input cables and input signals to be processed while maintaining high resolution and sensitivity and avoiding ambiguities. In the TCD application, where signal to noise and hence receiver array area is of paramount importance, array thinning is possible without reducing the receiver array area because a relatively small (compared to other applications) angular field of view is needed. Thinning with full aperture area imposes limitations on the angular field of view. Methods for expanding the field of view include using more elements than are active at any one time. For example, if the electronics is switched between two identical panels, the cross-range field of view at any depth is increased by the size of the panel. If the panels are pointed in slightly different directions so that overlapping or redundant beams are avoided, the field of view is doubled. A generalization of this approach involves the use of an array on a cylindrical or spherical surface. In the TCD application, the achievable angular resolution is poor, regardless of the method of thinning, or whether or not thinning is used. Once a section of a blood vessel is resolved from other vessels in Doppler, depth, and two angles (az and el), Post-Doppler sub-resolution processing locates that section to an accuracy that is one-tenth to one-twentieth of the resolution. This allows for precise tracking and accurate mapping. Tracking provides for the possibility of unattended long term monitoring and mapping aids the operator in selecting the point or points to be monitored. One of ordinary skill in the art will readily recognize that there are many options available in the design of any member of the family of sensors that utilizes any or all of the core technologies that comprise this invention, all of which are encompassed by the present invention. A two-dimensional array is established art that can be designed in many ways and can have many sizes and shapes (rectangular, round, etc.). As with other nonlimiting embodiments of the present invention set forth above, this embodiment is a non-invasive, continuous, unattended, volumetric, blood vessel tracking, ultrasound monitoring and diagnostic device for blood flow. It will enable unattended and continuous blood velocity measurement and monitoring as well as 3-dimensional vascular tracking and mapping using an easily attached, electronically steered, transducer probe that can be in the form of a small pad for monitoring application, when desired. Although a device of the present invention has applications with blood vessels in any part of the body, the cranial application will be used as a specific example. A device of the present invention can, for example: 1. Measure and continuously monitor blood velocity with a small low-profile probe that can be adhered, lightly taped, strapped, banded, or otherwise easily attached to the portion of the body where the vascular diagnosis or monitoring is required. 2. Track and maintain focus on multiple desired blood vessels in spite of movement. 3. Map 3-D blood flow; e.g., in the Circle of Willis (the central network of arteries that feeds the brain) or other critical vessels in the cranial volume. 4. Perform color velocity imaging and display a 3-D image of blood flow that is rotated via track ball or joystick until a desired view is selected. 5. Form and display a choice of projection, slice, or perspective views, including (1) a projection on a depth-azimuth plane, a B-scan, or a downward-looking perspective, (2) a projection on an azimuth-elevation plane, a C-scan, or a forward-looking perspective, or (3) a projection on an arbitrary plane, an arbitrary slice, or an arbitrary perspective. 6. Use a track ball and buttons to position circle markers on the points were measurement or monitoring of vector velocity is desired. 7. Move the track location along the blood vessel by using the track ball to slide the circle marker along the image of the vessel. 8. Display actual instantaneous and/or average vector velocity, estimated average volume flow, and/or Doppler spectral distribution. 9. Maintain a multi-day history and display average blood velocity versus time for each monitored vessel over many hours. 10. Sound an alarm when maximum or minimum velocity is exceeded or when emboli count is high; and maintain a log of emboli detected. 11. Track, map, and monitor small vessels (e.g., 1 mm in diameter), resolve vessels as close as 4 mm apart (for example), and locate them with an accuracy of ±0.1 mm, for example. This embodiment of the present invention will allow a person with little training to apply the sensor and position it based on an easily understood ultrasound image display. The unique sensor can continuously monitor artery blood velocity and volume flow for early detection of critical events. It will have an extremely low profile for easy attachment, and can track selected vessels; e.g., the middle cerebral artery (MCA), with no moving parts. If the sensor is pointed to the general volume location of the desired blood vessel (e.g., within ±1 cm.), it will lock to within ±0.1 mm of the point of maximum radial component of blood flow and remain locked in spite of patient movement. A device of the present invention can remain focused on the selected blood vessels regardless of patient movement because it produces and digitally analyzes, in real time, a 5-dimensional data base composed of signal-retum amplitude as a function of: 1. Depth, 2. Azimuth, 3. Elevation, 4. Radial component of blood velocity, 5. Time. Since a device of the present invention can automatically locate and lock onto the point in three dimensions having the maximum high-Doppler energy, i.e., maximum volume of blood having a significant radial velocity, unattended continuous blood velocity monitoring is one of its uses. By using the precise relative location of the point at which lock occurs as a function of depth, a device of the present invention can map the network of blood vessels as a 3-dimensional track without the hardware and computational complexity required to form a conventional ultrasound image. Using the radial component of velocity along with the three-dimensional blood path, a device of the present invention can directly compute parameters of blood flow, such as vector velocity, blood flow volume, and Doppler spectral distribution. A device having applications in a method of the present invention is a non-mechanical Doppler ultrasound-imaging sensor comprising probes, processing electronics, and display. Specific choices of probes allow the system to be used for transcranial Doppler (TCD), cardiac, dialysis, and other applications. Just as with other embodiments of the present invention set forth above, this embodiment has application for medical evaluation and monitoring multiple locations in the body. However, the transcranial Doppler application will be used as an nonlimiting example. FIG. 13 shows the overall TCD configuration and a typical definition of the display screen. The TCD system is comprised of one or two probes that may be attached to the head with a “telephone operator's band” or a Velcro strap. The interface and processing electronics is contained within a small sized computer. A thin cable containing from 52 to 120 micro coax cables, depending on the example probe design used, attaches the probe to the electronics in the computer. When the operator positions the probe on the head and activates the system, the Anterior, Middle and Posterior Cerebral Arteries and the Circle of Willis are mapped on the screen along with other blood vessels. The arteries or vessels of interest are selected by manually locating a cursor overlaid on the vessel 3-D map. The system locks onto the blood vessels and tracks their position electronically. A variety of selected parameters are displayed on the screen; e.g., the velocity, the pulse rate, depth of region imaged, gain and power level. Using only one probe the TCD can monitor multiple arteries (vessels) at a time. By way of example, presented on the screen are dual traces, one for each artery selected. The blood velocity can be dynamically monitored. As shown in FIG. 13 both the current blood velocity (dark traces) and any historic trace (lighter color) can be displayed simultaneously. The av rage blood velocity or estimated average flow for each artery is displayed below the respective velocity trace. The image shows the arteries and the channel used for each artery. When two probes are used, the display is split showing signals from both of them. For example, using a different probe (i.e., different size) with the same electronics and display, the unit can be used to measure and monitor the blood flow in a carotid artery. Similarly, it can be used to perform this function for dialysis, anesthesia, and in other procedures. The sensor is a two dimensional array of transducer elements (e.g., piezoelectric crystals) that are electronically activated in both transmit and receive to effect a scan. For example, if a square (N×N) array is used, up to N2 elements could be used at the same time. This is illustrated in FIG. 14 for the case of N=8. The array need not be square. Any M×N array may be utilized in this manner. All received signals (52 in the example of FIG. 13) are sampled, digitized, and processed. This can be done, for example, in a desk top or lap top personal computer with additional cards for electronics and real-time signal processing as illustrated in FIG. 13 and FIG. 21. The array is phase steered or time-delay steered, depending on the bandwidth utilized, which depends in turn on the desired range resolution. The angular field of view shown in FIG. 15 is limited by the existence of grating lobes caused by array thinning (spacing the array elements more than ½ wavelength apart). The concept is illustrated below for a 1-dimensional array forming a beam that measures only one angle. For a two-dimensional array, this represents a horizontal or vertical cut through the cluster of beams shown in FIG. 15. The frequency utilized for TCD is usually at or near 2 MHz because higher frequencies do not propagate well through bone and lower frequencies do not provide adequate reflection from the blood cells. However, other frequencies have applications when examining other parts of the body. With a propagation velocity of 1.54 millimeters per microsecond, the wavelength is 0.77 mm. If a filled array is utilized, the element size and array pitch would be d=0.77/2. For a cross-range resolution of 5.8 mm or less at a depth of 60 mm, the array size, L, must be at least 8 mm (Resolution=depth×wavelength/L). Since N=L/d in FIG. 2, N must exceed 21 and hence the array must have on the order of N2 or over 400 elements. If the desired resolution is halved, the array size doubles and the number of elements exceeds 1,600. The array in FIG. 14 is said to be “thinned” because it only has 52 elements. As explained above, “grating lobes” are ambiguities or extra, unwanted, beams caused by using a transducer array whose elements are too large and hence too far apart. The following analysis illustrates grating lobe suppression for the worst case of narrowband signals and phase-shift beam processing. Time delay processing using wideband signals would be similar, but would further attenuate or eliminate grating lobes, resulting in even better performance. Naturally, one of ordinary skill in the art can readily program a processor to suppress or limit grating lobes with the equations described herein using routine programming techniques. Let x=(d/λ)sin θ, (9) represent a normalization for the angle, θ, from which reflected acoustic energy arrives. The azimuth (or elevation) angle, θ, is zero in the broadside direction, perpendicular to the transducer array and d is the width (or length) of a single element of the receiver array. The wavelength of the radiated acoustic wave is λ=c/f, where c is the acoustic propagation velocity (1540 meters/second in soft tissue) and f is the acoustic frequency (usually between 1 and 10 megahertz). The wide pattern in FIG. 16a is the element pattern ae(θ)=sin πx/πx. (10) The pattern is the product of the element pattern, the array pattern, and cos θ. a(θ)=cos(θ)ae(x)aa(x) (11) Each of the two component patterns is plotted separately as a function of θ in FIG. 16a and the total pattern of equation (11) is plotted in FIG. 16b. In the far-field, i.e., for λr>>L2, where r is the range or depth and L is the length of the aperture, the array pattern steered to the angle θ=θ0 is a a ( x ) = ∑ n = 0 N - 1 w n ⅇ j 2 π n ( x - x 0 ) , ( 12 ) where wn is a weighting to reduce sidelobes and N is the number of elements in one dimension. As seen in FIG. 16a, equation (12) is periodic in x. The peak at θ=θ0 (θ0=0 in FIG. 16) is the desired beam and the others are grating lobes. In the near field, when focused at (r0θ0), equation (12) is replaced by the slightly better general Fresnel approximation: a a ( x , z ) = ∑ n = 0 N - 1 w n ⅇ j 2 π [ n ( x - x 0 ) + ( n - N - 1 2 ) 2 ( z - z 0 ) ] ( 13 ) (provided that that the range significantly exceeds the array size, r>L), where x=d sin θ/λ, as before, and z=d2 cos2 θ/λr. (14) Because the receiver aperture is sampled with a spatial period of d, the receiver array pattern will be periodic in sin θ, with a period of λ/d (equation 12). This periodicity means that the array pattern is ambiguous. When the array is pointed broadside (θ=0), it will also be pointed at the angle θ=sin−1 (λ/d), for example. In terms of the normalized variable, x, the period is unity. Since |sin θ| cannot exceed 1, the variable x is confined to the interval [−d/λ, d/λ]. The conventional element spacing is d=λ/2. Thus, in a conventional phased array, x is always between −0.5 and +0.5, and hence ambiguities are not encountered. In a highly thinned array (d>λ), there will normally be ambiguities or grating lobes as illustrated in FIG. 16a. The second grating lobe, at x=2 or θ=sin−1 (2 λ/d), is not real when d does not exceed 22. FIG. 16b shows that the unsteered total pattern does not exhibit grating lobes. In a two dimensional array, the elements could be rectangular instead of square (dx×dy), and the results would still be valid. Similar results could be obtained for an array in which the elements are staggered from row to row (and/or column to column). In FIG. 17 the same array is used as in FIG. 16, but the receiver element signals are combined with a phase taper that steers the beam to x=0.2 or θ=4.71°. In FIG. 17b, we see that the grating lobes are not completely suppressed, with the largest one at x=−1+0.2=−0.8 or θ=−19.180. FIG. 18 shows this in decibels. The worst-case grating lobe is attenuated by at least 12 dB, even in the stressing case of extremely narrow band operation. These Figures were produced in MATLAB, using the following software (m-file): % MPATTERN mpattern.m Script to plot monostatic patterns vs. theta Mt=90; wave_length=0.77; d=1.875, N=8, k=d/wave length t=−Mt:0.1:Mt; tr=pi.*t./180; x=k*sin(tr); p=pi*x+eps; R=sin(p)./p; R=R.*cos(tr); n=0:N−1; % xo=0; xo=0.2; % steered e=exp(j*n′*2*pi*(x−xo)); % w=hanning(N); % E=(2/N)*w′*e; E=(1/N)*ones(1,N)*e; subplot(211); plot(t, [abs(R);abs(E)]); ER=abs(E).*abs(R); % Monostatic subplot(212); plot(t, (abs(ER))); figure(2); plot(t,20*log10(abs(ER))); zoom on; The values of d and λ used in the above example are representative for a transcranial Doppler application of the invention. If f=2 MHz is chosen for the center frequency, the wavelength is 0.77 mm. An 8×8 array with a width and/or length of L=15 mm, provides a one dimensional thinning ratio of 2 d/λ=4.87. A 15 mm square array with half-wavelength elements would require more than 15,000 elements. By thinning, this number was reduced to 52 provided that the angular field of view is limited to 2×4.71=9.42°. For a 1 cm array at 2 MHz, the hyperfocal distance (where the 3 dB focal region extends to infinity) is L2/4λ=3.25 cm. For a 15 mm array, the hyperfocal distance is 7.3 cm. Thus, a fixed focus probe suffices for this application, but the quadratic phase distribution across the elements required to focus in depth should be added to the linear phase distributions required to steer the beams. Using the configuration described above, the cluster of beams in FIG. 15 is used to approximately locate the desired point for collecting the blood velocity signal. This is done initially, and is repeated periodically, in “mapping dwells” that are interspersed with normal measurement dwells. For example the output of each beam in the cluster would be Doppler processed by performing an FFT or equivalent transformation on a sequence of pulse returns. The pulse repetition frequency (PRF) would typically be less than or equal to 9 kHz to unambiguously achieve a depth of 8.5 cm for the TCD application. In order to obtain a velocity resolution finer than Av=2 cm per second (to distinguish brain death), a dwell of duration as long as T=λ/(2 Δν)=20 ms, or 170 pulses at 8.5 kHz, may be desired in the measurement mode. During monostatic mapping, 21 beams are scanned. If a mapping dwell is to be completed in 20 ms, only 8 pulses per beam are available, and an 8-pulse FFT would be utilized for each beam position. The example shown in FIGS. 16 through 18 was an 8 by 8 receiver array forming a 5 by 5 cluster of beams. This is an example of an approximate rule of thumb for this invention, that an Nelement linear array is recommended for use in producing N/2+1 beams forNeven and [N+1]/2 beams forNodd. Thus, a 16 by 10 element rectangular array would preferably be used to form a 9 by 6 cluster of beams, though the actual number of beams formed is arbitrary. Because receive beams are formed only in a limited angular region, a wide-angle receiver element pattern (which usually implies a small element) is not required. In fact, the size of the receiver element can be as large as the element spacing. Thus the receiver array is “thinned” only in the sense that the element spacing exceeds a half wavelength. Since the element size also exceeds a half wavelength, the array area is not reduced. It is thinned only in terms of number of elements, not in terms of receiver area. Consequently, there is no reduction in signal-to-noise ratio, nor a requirement for increased transmitter power. FIG. 19 illustrates a means for increasing the angular field of view in the azimuth direction by extending the array horizontally. A similar scheme could be used vertically to extend the elevation F.O.V. The 52-element array of FIG. 14 becomes a single panel of the extended array. One panel is active at a time in FIG. 19. The beamwidth for FIG. 14, in radians, is nominally given by λ/L. At a range or depth of R, the cross range resolution is Rλ/L (typically 3 to 5 mm). The F.O.V in millimeters at that same range is less than N/2+1=5 times that beamwidth. If a second panel is used in a planar configuration, the second panel translates the beam pattern to the right (or left) by the width of the panel, L=L2/2 (typically 8 mm). The field of view can be extended by more than this (it can even be doubled) by tilting the two panels in opposite directions to minimize the overlap in coverage of the two panels. FIG. 19, with L1≈L2, simultaneously provides: (1) a large F.O.V. in the L2 direction to allow for the simultaneous monitoring of two blood vessels more than an inch apart, (2) a large active array area for high sensitivity, and (3) a number of active elements below 60 and a total number of elements below 120. An alternative, shown in FIG. 20, has the array on the surface of a segment of a cylinder. This uses 52 elements at a time with a total of only 84 elements (and hence only 84 cables). The L1×L2′ active array translates around the curved surface as the beam is scanned horizontally. If a symmetric F.O.V. extension (azimuth and elevation) is desired, a spherical surface could be utilized. FIG. 21 is an overall block diagram depiction of the overall blood flow monitor. Most functions are performed by means of software in the digital processor. Naturally, one of ordinary skill in the art can readily program the processor to perform functions described herein using equations set forth herein and routine programming techniques. A possible implementation of the analog processing is diagrammed in FIG. 22. The A/D converter can be a bank of converters or one or more converters multiplexed amongst the 52 channels. If an extended array such as shown in FIG. 19 or 20 were used, a switch would be included between the 52 processing channels in FIG. 22 and the actual elements. Note that the 52 element array of FIG. 14 represents an 8×8 array with corners removed (52=8×84×3). Other possibilities include a 24 element array (24=6×6-4×3), a 120 element array (120=12×124×6), etc. The transmitter produces pulses for each active element at a pulse repetition frequency (PRF) of 8,500 pulses per second. Each pulse will be at a frequency of f0=2 MHz and will have a bandwidth, B, of at least 250 kHz (e.g., a pulse no more than 4 microseconds long). For measurement, only one or two beam positions need be insonated by a single probe. For mapping, many beam positions must be insonated, with several pulses on each for moving target indication (MTI) and/or Doppler processing. A measurement frame duration longer than 20 milliseconds (170 pulses at an 8.5 kHz PRF) may not be necessary because of the non-stationary (pulsed) nature of human blood flow. Mapping, requires several (4 to 11) pulses per beam position and many (e.g., 21 to 36) beam positions per frame. Since the Doppler resolution for mapping is not as fine as in the measurement mode, longer mapping frames can be used. If only 21 beams are formed with 8 pulses on each or if up to 34 beams are formed with only 5 pulses on each, a frame duration of 20 ms can be maintained even during search and mapping. FIG. 22 shows 52 identical receiver chains comprising 1. Processor controlled time gain control and time gate (open for up to 26 microseconds for each pulse). 2. A limiter for dynamic range control. 3. A low noise amplifier (LNA). 4. A low pass filter (to pass |f|<fo+B/2 (e.g., |f|<2.125 kHz) and reject |f|>5.875 kHz by at least 40 dB (assuming fo=2 M Hz and B=250 kHz). A/D conversion (typically 12 to 16 bits) is performed at an 8 MHz rate for each channel in FIG. 22. This keeps the analog filtering requirements extremely simple. It also permits extremely large bandwidths (up to 2 MHz) and time-delay steering. For narrower bandwidths and phase-shift steering, bandpass analog filtering and much lower sampling rates (determined by B rather than fo) could be used. For the 8 MHz sampling rate, either time-delay or phase-shift beam steering can be utilized (depending on signal bandwidth). FIG. 22 depicts time delay steering for the transmitter. The distance from each array element to each focal point (each beam center at a nominal depth (e.g., 60 mm for TCD) would be pre-computed and stored either as a time delay or as a phase shift (depending on the type of steering) for each element for each beam. If phase shift steering were utilized on transmit, the transmitted signal could be created digitally in the processor, followed by D/A conversion for each element. Hence FIG. 22 represents only one possible embodiment of the invention. An example of the digital receiver processing for the case of an 8 MHz sampling rate per channel is described below. The input is 208 12 or 16 bit samples per pulse (8 samples per microsecond×26 microseconds to allow for a 4 cm deep radial mapping field of view), 8,500 pulses/second, and 52 channels. This results in a maximum average rate of 52×208×8500=91.9 MegaSamples per second (or 1.84 million samples in a 20 ms frame). During measurement, the range interval can be narrowed to less than 1 cm, reducing the number of samples per pulse to 32. The average rate for measurement and monitoring becomes 14 megasamples per second. The receiver processing steps are as follows: Buffer (to allow subsequent processing to be performed at the average rate). Digitally D wn Convert t Baseband (make I and Q). 52 channels in parallel. Multiply input samples by samples of a 2 MHz cosine wave and −sine wave to create In-phase and Quadrarture samples, respectively. Since the samples are ¼ cycle apart, the muluplicands are all 0, 1, or −1, and hence no multiplications are needed. If r(j,p) is the real pth sample from the jth channel, the complex low-pass signal, s(j, p), has a real part for p=0, 1, 2, 3, 4, 5, . . . given by r(j,0), 0, −r(j,2), 0, r(j,4), 0, . . . and an imaginary part given by 0, −r(j,1), 0, r(j,3), 0, −r(j,5), . . . This provides a data rate 2 times the input rate because the data is now complex. Pre-Decimation Low-Pass Digital Filter. Filter 52 complex channels. Pass |f|<B/2, reject |f|>r−B/2, where r is the sampling rate after sample rate decimation (e.g., 1 MHz). If B=250 kHz, r could be as low as 500 kHz. If B is large, r could be 2 or 3 MHz. If receiver phase-shift steering were to be performed, the output samples would be computed at the decimated rate. If receiver time-delay steering is to be used, we output 8 million complex samples per second and postpone sample rate decimation until after beam formation. Perform MTI or create coarse Doppler cells. For every channel and every range sample, either digitally high-pass filter the sequence of pulse returns to suppress clutter from tissue and bone or perform 52×208 8-point discrete Fourier transforms (DFT's or FFTs) for each mapping frame. (Six points of the 8-point complex DFT provides 3 positive and 3 negative coarse Doppler cells.) Perform Digital Beamforming. Case 1: Time Delay Beamforming with Sample Rate Decimation uses a set of pre-computed time delays to reduce 52 complex channels with 208 samples per pulse to one of M (e.g. 21) complex beam outputs with 25 samples (range cells) per pulse. The example given here assumes 8:1 decimation. The maximum delay is slightly less than 0.75 μs=6 T, where T=⅛ microsecond is the time between input samples. For a given pulse return, the kth sample (k=1, 2, . . . , 25) of the ith beam, i=1, 2, . . . , M, is denoted by b(i, k). The pth sample (p=1, 2, . . . , 208) of the jth input channel (j=1, 2, . . . , 52) is denoted by s(j,p). Let dij be the delay required for the signal in channel j to produce beam i. For a given pulse return, the kth complex 1 MHz rate output sample for beam i is b ( i , k ) = ∑ j = 1 52 { a ij s ( j , 8 [ k + 1 ] - b ij ) + ( 1 - a ij ) s ( j , 8 [ k + 1 ] - b ij - 1 ) } where bij is the integer part of dij/T (between 0 and 6) and aij is the fractional remainder (between 0 and 1). Determine power or amplitude in each output Doppler bin as I2+Q2 or its square root: Case 2: Phase-shift beamforming of already decimated data involves only a sequence of inner products of 52-dimensional complex vectors of element values with a complex vector of representing the required phase shifts. Display Coarse Blood-Vessel Color-Flow Map. Coarse blood vessel map is the set of range, azimuth, and elevation cells with high power, with 6 Doppler values. Blue and red represent positive and negative Doppler, with saturation related to radial velocity and intensity related to power. Initialize Acquisition. The user, looking at an azimuth-elevation Coarse Map (with depth automatically truncated to a set of values that should include the MCA), moves the transducer and looks for a high-intensity, saturated spot. He can center the probe on that spot or he can have a device of the present invention display a range interval corresponding to the ACA, in which case he can make sure that both vessels are well within the angular field of view of the probe. Acquisition and Tracking of one or two points being monitored. This is done with a single transmit beam focused on the spot identified above for several frames. Digital Down-conversion, low-pass filtering, and MTI are performed as before, but beamforming is different. Five receive beams are simultaneously formed. These are a sum beam and four monopulse difference beams, all steered to the same point as the transmit beam. Each monopulse beam is equivalent to the difference between the outputs of a pair of beams displaced on opposite sides of the focal point. The four monopulse pairs are in 45 degree intervals with the first being horizontal, and the third being vertical. The monopulse-difference output with the largest magnitude is divided by the output of the sum beam. The imaginary part is the “monopulse ratio” used to re-steer the beam (in the difference pair direction) so that it is better centered on the vessel. This procedure can be repeated in an effort to drive all four monopulse ratios to zero. Measurement and Tracking. Tracking continues as described above during the measurement mode. Measurement is made with fine Doppler resolution (128 point FFT) applied to only the sum beam. In a 15 ms frame, data from 128 pulses are collected (52 channels, 6 range samples). The pulses are Hamming weighted and FFT'd. This produces 128 Doppler bins (for each range bin and element), 66.4 times a second. Real sum beam outputs would then be produced (using monopulse-guided steering) for each of 64 to 126 of these Doppler bins. Track maintenance and re-acquisition. Tracking is continued in parallel with measurement. If a monopulse ratio suddenly deviates far from zero and is not brought back to zero in one or two iterations, loss of track is declared. Re-acquisition is attempted autonomously by re-steering the beam by an amount determined by correlating a current color flow map with a stored earlier version (from before track was lost). If this is unsuccessful, (monopulse ratios do not all converge to zero) an alarm is sounded so that the user can return to repeat initialization of acquisition. Correlation with previous maps will be periodically applied to prevent wandering of the data collection point along the vessel being tracked. For tracking purposes, a monopulse tracking method described above can be used. FIG. 23 illustrates the segment of a vessel in a single resolution cell, after rotation. The resolution cell shown is not a cube because the range resolution might be finer than the cross-range resolution. The illustrated circular cylinder represents blood cells in a vessel reflecting energy at a fixed Doppler frequency. These represent a cylindrical annulus of blood cells, at a constant distance from the vessel wall, moving with approximately the same velocity. In the single resolution cell of FIG. 23, the return at the highest Doppler would represent a line in three-dimensional space (the axis of the vessel) and hence a point on the azimuth axis after rotation. When applied to the highest Doppler output, the Sum beam would have broad peak at zero azimuth (a=0) and the monopulse ratio, r=Az/Sum, will be a linear function of the azimuth angle to which the array is phase steered: r(a)=ka. This result can be attained by applying the same phase across the aperture for the Az and Sum beams, but using the derivative of the Sum beam amplitude weights with respect to x and y respectively for the Az and El aperture weights. Many other variations and modifications of the invention will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The above-described embodiments are, therefore, intended to be merely exemplary, and all such variations and modifications are included within the scope of the invention as defined in the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention This invention relates to ultrasonic acoustic imaging, primarily for medical purposes. 2. Brief Description of the Background Art Ultrasonic acoustic imaging finds many uses, particularly in the field of non-invasive medical testing. Direct detection of the emitted acoustic frequency permits, for example, prenatal fetal imaging. Detection of Doppler shifted acoustic frequencies permits observation of flow of a particle-containing liquid, for example, blood flow. Acoustic imaging equipment utilizes a probe that is applied to the skin of the patient overlying the part of the body being investigated. At the end of the probe is an array of transducers, usually piezoelectric, that are excited by bursts of electrical energy at the ultrasonic frequency and modulated to transmit pulses of ultrasonic energy into the body region being investigated. The subsurface structures reflect some of that energy, either at the transmitted frequency or Doppler shifted, back to the probe, where it is detected by piezoelectric receiver elements in the probe. One application of this technology to the three dimensional mapping and tracking of blood flow is disclosed in parent U.S. application Ser. No. 09/926,666, which is scheduled to issue on Jan. 27, 2004 as U.S. Pat. No. 6,682,483. The pertinent text of that application is included herein below. | <SOH> SUMMARY OF THE INVENTION <EOH>In order to see slower moving blood by Doppler ultrasound investigation, as the blood moves from major blood vessels into arterioles and capillaries, it is necessary to lower the pulse repetition frequency. This permits the phase of the Doppler-shifted signal to change more measurably from one pulse to the next. However, if the frame rate is lowered to lower the pulse repetition frequency, less data is collected in a given time, exacting a penalty in less averaging and reducing the signal to noise ratio below the desired level. The herein disclosed invention is an interleaving technique that lowers the effective pulse repetition frequency at each probe position without exacting these system penalties. | 20040126 | 20070703 | 20050106 | 61587.0 | 0 | SMITH, RUTH S | PULSE INTERLEAVING IN DOPPLER ULTRASOUND IMAGING | SMALL | 1 | CONT-ACCEPTED | 2,004 |
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10,764,935 | ACCEPTED | Method of using aldehyde-functionalized polymers to enhance paper machine dewatering | A method of enhancing the dewatering of a paper sheet on a paper machine comprising adding to the paper sheet about 0.05 lb/ton to about 15 lb/ton, based on dry fiber, of one or more aldehyde functionalized polymers comprising amino or amido groups wherein at least about 15 mole percent of the amino or amido groups are functionalized by reacting with one or more aldehydes and wherein the aldehyde functionalized polymers have a molecular weight of at least about 100,000. | 1. A method of enhancing the dewatering of a paper sheet on a paper machine comprising adding to the paper sheet about 0.05 lb/ton to about 15 lb/ton, based on dry fiber, of one or more aldehyde functionalized polymers comprising amino or amido groups wherein at least about 15 mole percent of the amino or amido groups are functionalized by reacting with one or more aldehydes and wherein the aldehyde functionalized polymers have a weight average molecular weight of at least about 100,000 g/mole. 2. The method of claim 1 wherein the aldehyde functionalized polymers are selected from the group consisting of aldehyde functionalized polyamines and aldehyde functionalized polyamides. 3. The method of claim 1 wherein the aldehydes are selected from formaldehyde, paraformaldehyde, glyoxal and glutaraldehyde. 4. The method of claim 1 wherein the aldehyde functionalized polymer is an aldehyde functionalized polyamide. 5. The method of claim 4 wherein the aldehyde functionalized polyamide is an aldehyde-functionalized polymer comprising 100 mole percent of one or more nonionic monomers. 6. The method of claim 4 wherein the aldehyde functionalized polyamide is an aldehyde functionalized copolymer comprising about 5 to about 99 mole percent of one or more acrylamide monomers and about 95 mole percent to about 1 mole percent of one or more cationic, anionic or zwitterionic monomers, or a mixture thereof. 7. The method of claim 6 wherein the aldehyde functionalized polyamide is an aldehyde-functionalized copolymer comprising 1 to about 50 mole percent of one or more anionic monomers and 99 to about 50 mole percent of one or more nonionic monomers. 8. The method of claim 6 wherein the aldehyde functionalized polyamide is an aldehyde-functionalized copolymer comprising 1 to about 30 mole percent of one or more anionic monomers and 99 to about 70 mole percent of one or more nonionic monomers. 9. The method of claim 6 wherein the aldehyde functionalized copolymer is an aldehyde-functionalized amphoteric polymer comprising up to about 40 mole percent of one or more cationic monomers and up to about 20 mole percent of one or more anionic monomers. 10. The method of claim 6 wherein the aldehyde functionalized copolymer is an aldehyde-functionalized amphoteric polymer comprising about 5 to about 10 mole percent of one or more cationic monomers and about 0.5 to about 4 mole percent of one or more anionic monomers. 11. The method of claim 6 wherein the aldehyde functionalized copolymer is an aldehyde-functionalized zwitterionic polymer comprising about 1 to about 95 mole percent of one or more zwitterionic monomers. 12. The method of claim 6 wherein the aldehyde functionalized copolymer is an aldehyde-functionalized zwitterionic polymer comprising about 1 to about 50 mole percent of one or more zwitterionic monomers. 13. The method of claim 6 wherein the aldehyde functionalized polyamide is an aldehyde functionalized copolymer comprising about 50 to about 99 mole percent of one or more acrylamide monomers and about 50 to about 1 mole percent of one or more cationic monomers. 14. The method of claim 13 wherein at least about 20 mole percent of the amide groups of the polyamide have reacted with aldehyde. 15. The method of claim 1 wherein the aldehyde functionalized polymer is a copolymer comprising about 50 to about 99 mole percent of one or more acrylamide monomers and about 50 to about 1 mole percent of one or more cationic monomers wherein the copolymer is functionalized with glyoxal. 16. The method of claim 15 wherein the cationic monomer is a diallyl-N,N-disubstituted ammonium halide monomer. 17. The method of claim 16 wherein about 20 to about 50 mole percent of the amide groups of the copolymer have reacted with glyoxal. 18. The method of claim 16 wherein the nonionic monomer is acrylamide and the diallyl-N,N-disubstituted ammonium halide monomer is diallyldimethylammonium chloride. 19. The method of claim 18 wherein the aldehyde-functionalized polymer has a molecular weight of at least 300,000 g/mole. 20. The method of claim 19 wherein the aldehyde-functionalized polymer is a copolymer comprising about 70 to about 99 mole percent of acrylamide and about 1 to about 30 mole percent of diallyldimethylammonium chloride functionalized with glyoxal. 21. The method of claim 20 wherein about 20 to about 26 mole percent of the amide groups of the copolymer have reacted with glyoxal. 22. The method of claim 21 wherein about 0.5 lb/ton to about 3 lb/ton, based on dry fiber, of glyoxylated copolymer is added to the paper sheet. 23. The method of claim 1 wherein the aldehyde functionalized polymer is sprayed onto the paper sheet prior to press dewatering. | TECHNICAL FIELD This is a method of enhancing paper machine dewatering using aldehyde-functionalized polymers having a specific level of functionalization. BACKGROUND OF THE INVENTION Papermaking comprises taking a slurry of papermaking raw materials at a consistency (weight percent solids) in the range 0.1 to 1.0 weight percent and dewatering it to form a sheet with a final consistency of about 95 weight percent. Paper machines accomplish this dewatering through a series of different processes which include from the beginning to end: 1) gravity or inertial dewatering (early forming section of the machine); 2) vacuum dewatering (late forming section of the machine); 3) press dewatering (press section of the machine); and 4) thermally evaporating the water (dryer section of the machine). The cost of dewatering increases in going from 1 to 4, which makes it advantageous to remove as much water as possible in the earlier stages. The rate of paper production or, equivalently, the machine speed is dictated by the rate at which the water can be removed, and consequently, any chemical treatment which can increase the rate of water removal has value for the papermaker. Many grades of paper require the use of retention aid chemicals for their manufacture in order to retain the fine particles found in the raw materials used to make the paper. It is well known in the paper industry that these retention aids can also enhance the rate of gravity, inertial, and vacuum dewatering or drainage, as it is often called. Such retention chemicals include the well known flocculants, coagulants, and microparticles used in the industry. Existing laboratory free and vacuum drainage tests can readily identify the drainage effects of these retention aid chemicals. The production rate for the vast majority of paper machines is limited by the drying capacity of the machine's dryer section. Consequently, the consistency of the paper sheet leaving the press section and going into the dryer section is most often critical in determining the paper machine speed or production rate. The effects of chemical additives on press dewatering are unclear with little information available on this topic. The effect of retention aid chemicals on press dewatering is often reported to be detrimental as a consequence of the decreased consistency entering the press as a result of increased water retention or reduction in press efficiency resulting from a loss in sheet formation. Both these factors arise from the flocculation of the papermaking particles by the retention chemicals. Because the consistency of the sheet leaving the press section is most often the most critical factor in determining machine speed, any treatment capable of increasing this consistency would obviously be highly desirable. Currently, no chemical treatments are known to be marketed as commercial press dewatering aids, although anecdotal reports suggest that some polymers can favorably effect out going press consistency. Accordingly, there is an ongoing need to develop compositions having effective press dewatering activity. Glyoxylated polyvinylamides prepared from glyoxal and polyvinylamide in a mole ratio of 0.1 to 0.2 are disclosed as wet strength resins in U.S. Pat. No. 3,556,932. Low molecular weight glyoxylated cationic polyacrylamides prepared from glyoxal and cationic polyvinylamide in a ratio of 0.1-0.5:1 are disclosed as temporary wet strength resins in U.S. Pat. No. 4,605,702. A method of imparting strength to paper by adding to a pulp slurry a mixed resin comprising an aminopolyamide-epichlorohydrin resin and a glyoxylated acrylamide-dimethyl diallyl ammonium chloride resin prepared from glyoxal and acrylamide-dimethyl diallyl ammonium chloride copolymer in a molar ratio of about 2-0.5:1 is disclosed in U.S. Pat. No. 5,674,362. SUMMARY OF THE INVENTION This invention is a method of enhancing the dewatering of a paper sheet on a paper machine comprising adding to the paper sheet about 0.05 lb/ton to about 15 lb/ton, based on dry fiber, of one or more aldehyde functionalized polymers comprising amino or amido groups wherein at least about 15 mole percent of the amino or amido groups are functionalized by reacting with one or more aldehydes and wherein the aldehyde functionalized polymers have a weight average molecular weight of at least about 100,000 g/mole. DETAILED DESCRIPTION OF THE INVENTION “Acrylamide monomer” means a monomer of formula wherein R1 is H or C1-C4 alkyl and R2 is H, C1-C4 alkyl, aryl or arylalkyl. Preferred acrylamide monomers are acrylamide and methacrylamide. Acrylamide is more preferred. “Aldehyde” means a compound containing one or more aldehyde (—CHO) groups, where the aldehyde groups are capable of reacting with the amino or amido groups of a polymer comprising amino or amido groups as described herein. Representative aldehydes include formaldehyde, paraformaldehyde, glutaraldehyde, glyoxal, and the like. Glyoxal is preferred. “Alkyl” means a monovalent group derived from a straight or branched chain saturated hydrocarbon by the removal of a single hydrogen atom. Representative alkyl groups include methyl, ethyl, n- and iso-propyl, cetyl, and the like. “Alkylene” means a divalent group derived from a straight or branched chain saturated hydrocarbon by the removal of two hydrogen atoms. Representative alkylene groups include methylene, ethylene, propylene, and the like. “Amido group” means a group of formula —C(O)NHY1 where Y1 is selected from H, alkyl, aryl and arylalkyl. “Amino group” means a group of formula —NHY2 where Y2 is selected from H, alkyl, aryl and arylalkyl. “Amphoteric” means a polymer derived from both cationic monomers and anionic monomers, and, possibly, other non-ionic monomer(s). Representative amphoteric polymers include copolymers composed of acrylic acid and DMAEA.MCQ, terpolymers composed of acrylic acid, DADMAC and acrylamide, and the like. “Aryl” means an aromatic monocyclic or multicyclic ring system of about 6 to about 10 carbon atoms. The aryl is optionally substituted with one or more C1-C20 alkyl, alkoxy or haloalkyl groups. Representative aryl groups include phenyl or naphthyl, or substituted phenyl or substituted naphthyl. “Arylalkyl” means an aryl-alkylene- group where aryl and alkylene are defined herein. Representative arylalkyl groups include benzyl, phenylethyl, phenylpropyl, 1-naphthylmethyl, and the like. Benzyl is preferred. “Diallyl-N,N-disubstituted ammonium halide monomer” means a monomer of formula (H2C═CHCH2)2N+R3R4X− wherein R3 and R4 are independently C1-C20 alkyl, aryl or arylalkyl and X is an anionic counterion. Representative anionic counterions include halogen, sulfate, nitrate, phosphate, and the like. A preferred anionic counterion is halogen. Halogen is preferred. A preferred diallyl-N,N-disubstituted ammonium halide monomer is diallyldimethylammonium chloride. “Halogen” means fluorine, chlorine, bromine or iodine. “Monomer” means a polymerizable allylic, vinylic or acrylic compound. The monomer may be anionic, cationic, nonionic or zwitterionic. Vinyl monomers are preferred, acrylic monomers are more preferred. Representative non-ionic, water-soluble monomers include acrylamide, methacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, N-isopropylacrylamide, N-vinylformamide, N-vinylmethylacetamide, N-vinyl pyrrolidone, hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, N-t-butylacrylamide, N-methylolacrylamide, vinyl acetate, vinyl alcohol, and the like. Representative anionic monomers include acrylic acid, and it's salts, including, but not limited to sodium acrylate, and ammonium acrylate, methacrylic acid, and it's salts, including, but not limited to sodium methacrylate, and ammonium methacrylate, 2-acrylamido-2-methylpropanesulfonic acid (AMPS), the sodium salt of AMPS, sodium vinyl sulfonate, styrene sulfonate, maleic acid, and it's salts, including, but not limited to the sodium salt, and ammonium salt, sulfonate, itaconate, sulfopropyl acrylate or methacrylate or other water-soluble forms of these or other polymerisable carboxylic or sulphonic acids. Sulfomethylated acrylamide, allyl sulfonate, sodium vinyl sulfonate, itaconic acid, acrylamidomethylbutanoic acid, fumaric acid, vinylphosphonic acid, vinylsulfonic acid, allylphosphonic acid, sulfomethylated acrylamide, phosphonomethylated acrylamide, itaconic anhydride, and the like. Representative cationic monomers include allyl amine, vinyl amine, dialkylaminoalkyl acrylates and methacrylates and their quaternary or acid salts, including, but not limited to, dimethylaminoethyl acrylate methyl chloride quaternary salt (DMAEA.MCQ), dimethylaminoethyl acrylate methyl sulfate quaternary salt, dimethyaminoethyl acrylate benzyl chloride quaternary salt, dimethylaminoethyl acrylate sulfuric acid salt, dimethylaminoethyl acrylate hydrochloric acid salt, dimethylaminoethyl methacrylate methyl chloride quaternary salt, dimethylaminoethyl methacrylate methyl sulfate quaternary salt, dimethylaminoethyl methacrylate benzyl chloride quaternary salt, dimethylaminoethyl methacrylate sulfuric acid salt, dimethylaminoethyl methacrylate hydrochloric acid salt, dialkylaminoalkylacrylamides or methacrylamides and their quaternary or acid salts such as acrylamidopropyltrimethylammonium chloride, dimethylaminopropyl acrylamide methyl sulfate quaternary salt, dimethylaminopropyl acrylamide sulfuric acid salt, dimethylaminopropyl acrylamide hydrochloric acid salt, methacrylamidopropyltrimethylammonium chloride, dimethylaminopropyl methacrylamide methyl sulfate quaternary salt, dimethylaminopropyl methacrylamide sulfuric acid salt, dimethylaminopropyl methacrylamide hydrochloric acid salt, diethylaminoethylacrylate, diethylaminoethylmethacrylate, diallyldiethylammonium chloride and diallyldimethyl ammonium chloride (DADMAC). Alkyl groups are generally C1-4 alkyl. “Zwitterionic monomer” means a polymerizable molecule containing cationic and anionic (charged) functionality in equal proportions, so that the molecule is net neutral overall. Representative zwitterionic monomers include N,N-dimethyl-N-acryloyloxyethyl-N-(3-sulfopropyl)-ammonium betaine, N,N-dimethyl-N-acrylamidopropyl-N-(2-carboxymethyl)-ammonium betaine, N,N-dimethyl-N-acrylamidopropyl-N-(3-sulfopropyl)-ammonium betaine, N,N-dimethyl-N-acrylamidopropyl-N-(2-carboxymethyl)-ammonium betaine, 2-(methylthio)ethyl methacryloyl-S-(sulfopropyl)-sulfonium betaine, 2-[(2-acryloylethyl)dimethylammonio]ethyl 2-methyl phosphate, 2-(acryloyloxyethyl)-2′-(trimethylammonium)ethyl phosphate, [(2-acryloylethyl)dimethylammonio]methyl phosphonic acid, 2-methacryloyloxyethyl phosphorylcholine (MPC), 2-[(3-acrylamidopropyl)dimethylammonio]ethyl 2′-isopropyl phosphate (AAPI), 1-vinyl-3-(3-sulfopropyl)imidazolium hydroxide, (2-acryloxyethyl) carboxymethyl methylsulfonium chloride, 1-(3-sulfopropyl)-2-vinylpyridinium betaine, N-(4-sulfobutyl)-N-methyl-N, N-diallylamine ammonium betaine (MDABS), N,N-diallyl-N-methyl-N-(2-sulfoethyl)ammonium betaine, and the like. “Papermaking process” means a method of making paper products from pulp comprising forming an aqueous cellulosic papermaking furnish, draining the furnish to form a sheet and drying the sheet. The steps of forming the papermaking furnish, draining and drying may be carried out in any conventional manner generally known to those skilled in the art. Conventional microparticles, alum, cationic starch or a combination thereof may be utilized as adjuncts with the polymer treatment of this invention, though it must be emphasized that no adjunct is required for effective dewatering activity. PREFERRED EMBODIMENTS The aldehyde-functionalized polymers according to this invention are prepared by reacting a polymer comprising amino or amido groups with one or more aldehydes. The polymer comprising amino or amide groups can have various architectures including linear, branched, star, block, graft, dendrimer, and the like. Preferred polymers comprising amino or amido groups include polyamines and polyamides. The polyamides and polyamides may be prepared by copolymerizing monomers under free radical forming conditions using any number of techniques including emulsion polymerization, dispersion polymerization and solution polymerization. Polyamines may also be prepared by modification of a pre-formed polyamide, for example by hydrolysis of acrylamide-vinylformamide copolymer using acid or base as described in U.S. Pat. Nos. 6,610,209 and 6,426,383. Polyaminoamides may also be prepared by direct amidation of polyalkyl carboxylic acids and transamidation of copolymers containing carboxylic acid and (meth)acrylamide units as described in U.S. Pat. No. 4,919,821. “Emulsion polymer” and “latex polymer” mean a polymer emulsion comprising an aldehyde-functionalized polymer according to this invention in the aqueous phase, a hydrocarbon oil for the oil phase and a water-in-oil emulsifying agent. Inverse emulsion polymers are hydrocarbon continuous with the water-soluble polymers dispersed within the hydrocarbon matrix. The inverse emulsion polymers are then “inverted” or activated for use by releasing the polymer from the particles using shear, dilution, and, generally, another surfactant. See U.S. Pat. No. 3,734,873, incorporated herein by reference. Representative preparations of high molecular weight inverse emulsion polymers are described in U.S. Pat. Nos. 2,982,749; 3,284,393; and 3,734,873. See also, Hunkeler, et al., “Mechanism, Kinetics and Modeling of the Inverse-Microsuspension Homopolymerization of Acrylamide,” Polymer, vol. 30(1), pp 127-42 (1989); and Hunkeler et al., “Mechanism, Kinetics and Modeling of Inverse-Microsuspension Polymerization 2. Copolymerization of Acrylamide with Quaternary Ammonium Cationic Monomers,” Polymer, vol. 32(14), pp 2626-40 (1991). The aqueous phase is prepared by mixing together in water one or more water-soluble monomers, and any polymerization additives such as inorganic salts, chelants, pH buffers, and the like. The oil phase is prepared by mixing together an inert hydrocarbon liquid with one or more oil soluble surfactants. The surfactant mixture should have a low hydrophilic-lypophilic balance (HLB), to ensure the formation of an oil continuous emulsion. Appropriate surfactants for water-in-oil emulsion polymerizations, which are commercially available, are compiled in the North American Edition of McCutcheon's Emulsifiers & Detergents. The oil phase may need to be heated to ensure the formation of a homogeneous oil solution. The oil phase is then charged into a reactor equipped with a mixer, a thermocouple, a nitrogen purge tube, and a condenser. The aqueous phase is added to the reactor containing the oil phase with vigorous stirring to form an emulsion. The resulting emulsion is heated to the desired temperature, purged with nitrogen, and a free-radical initiator is added. The reaction mixture is stirred for several hours under a nitrogen atmosphere at the desired temperature. Upon completion of the reaction, the water-in-oil emulsion polymer is cooled to room temperature, where any desired post-polymerization additives, such as antioxidants, or a high HLB surfactant (as described in U.S. Pat. No. 3,734,873) may be added. The resulting emulsion polymer is a free-flowing liquid. An aqueous solution of the water-in-oil emulsion polymer can be generated by adding a desired amount of the emulsion polymer to water with vigorous mixing in the presence of a high-HLB surfactant (as described in U.S. Pat. No. 3,734,873). “Dispersion polymer” polymer means a water-soluble polymer dispersed in an aqueous continuous phase containing one or more organic or inorganic salts and/or one or more aqueous polymers. Representative examples of dispersion polymerization of water-soluble polymers in an aqueous continuous phase can be found in U.S. Pat. Nos. 5,605,970; 5,837,776; 5,985,992; 4,929,655; 5,006,590; 5,597,859; and 5,597,858 and in European Patent Nos. 183,466; 657,478; and 630,909. In a typical procedure for preparing a dispersion polymer, an aqueous solution containing one or more inorganic or organic salts, one or more water-soluble monomers, any polymerization additives such as processing aids, chelants, pH buffers and a water-soluble stabilizer polymer is charged to a reactor equipped with a mixer, a thermocouple, a nitrogen purging tube, and a water condenser. The monomer solution is mixed vigorously, heated to the desired temperature, and then a free radical initiator is added. The solution is purged with nitrogen while maintaining temperature and mixing for several hours. After this time, the mixture is cooled to room temperature, and any post-polymerization additives are charged to the reactor. Water continuous dispersions of water-soluble polymers are free flowing liquids with product viscosities generally 100-10,000 cP, measured at low shear. In a typical procedure for preparing solution polymers, an aqueous solution containing one or more water-soluble monomers and any additional polymerization additives such as chelants, pH buffers, and the like, is prepared. This mixture is charged to a reactor equipped with a mixer, a thermocouple, a nitrogen purging tube and a water condenser. The solution is mixed vigorously, heated to the desired temperature, and then one or more free radical polymerization initiators are added. The solution is purged with nitrogen while maintaining temperature and mixing for several hours. Typically, the viscosity of the solution increases during this period. After the polymerization is complete, the reactor contents are cooled to room temperature and then transferred to storage. Solution polymer viscosities vary widely, and are dependent upon the concentration and molecular weight of the active polymer component. The polymerization reactions are initiated by any means which results in generation of a suitable free-radical. Thermally derived radicals, in which the radical species results from thermal, homolytic dissociation of an azo, peroxide, hydroperoxide and perester compound are preferred. Especially preferred initiators are azo compounds including 2,2′-azobis(2-amidinopropane) dihydrochloride, 2,2′-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride, 2,2′-azobis(isobutyronitrile) (AIBN), 2,2′-azobis(2,4-dimethylvaleronitrile) (AIVN), and the like. The polymerization processes can be carried out as a batch process or in steps. In a batch process, all of the reactive monomers are reacted together, whereas in a step or semi-batch process, a portion of the reactive monomer is withheld from the main reaction and added over time to affect the compositional drift of the copolymer or the formation of the dispersion particles. The polymerization and/or post polymerization reaction conditions are selected such that the resulting polymer comprising amino or amido groups has a molecular weight of at least about 1,000 g/mole, preferably about 2,000 to about 10,000,000 g/mole. The polymer comprising amino or amido groups is then functionalized by reaction with one or more aldehydes. Suitable aldehydes include any compound containing at least one aldehyde (—CHO) functional group having sufficient reactivity to react with the amino or amido groups of the polymer. Representative aldehydes include formaldehyde, paraformaldehyde, glutaraldehyde, glyoxal, and the like. Glyoxal is preferred. The aldehyde-functionalized polymer is prepared by reacting the polyamide or polyamine with aldehyde at a pH between 4 to 12. The total concentration of polymer backbone plus aldehyde is between about 5 to about 35 weight percent. Generally, an aqueous solution of the polymer backbone is prepared for better reaction rate control and increased product stability. The pH of the aqueous polymer backbone solution is increased to between about 4 to about 12. The reaction temperature is generally about 20 to about 80° C. preferably about 20 to about 40° C. An aqueous aldehyde solution is added to the aqueous polymer backbone solution with good mixing to prevent gel formation. After the addition of aldehyde the pH is adjusted to about 4 to about 12 to achieve the desired reaction rate. After the adjustment of the pH generally the amount of monoreacted amide/amine is optimum for the given ratio of aldehyde to amide/amine and the amount of direacted amide/amine is low. The rate of viscosity increase is monitored during the reaction using a Brookfield viscometer. A viscosity increase of 0.5 cps indicates an increase in polymer molecular weight and an increase in the amount of direacted amide/amine. The amount of monoreacted amide/amine is generally maintained during the viscosity increase but the amount of direacted amide/amine increases with viscosity. Generally, the desired viscosity increase corresponds to a desired level of monoreacted amide/amine, direacted amide/amine and molecular weight. The rate of reaction depends on the temperature, total concentration of polymer and aldehyde, the ratio of aldehyde to amide/amine functional groups and pH. Higher rates of glyoxylation are expected when the temperature, total concentration of polymer and aldehyde, the ratio of aldehyde to amide/amine functional groups or pH is increased. The rate of reaction can be slowed down by decreasing the total concentration of polymer and aldehyde, temperature, the ratio of aldehyde to amide/amine functional groups or pH (to between about 2 to about 3.5). The amount of unreacted aldehyde at the end of the reaction increases as the ratio of aldehyde to amide/amine functional groups is increased. However, the total amount of monoreacted and direacted amide/amine becomes larger. For example, reaction of a 95/5 mole percent diallyldimethylammonium chloride/acrylamide copolymer with glyoxal in a molar ratio of 0.4 to 1 glyoxal to acrylamide results in a 95/5 mole percent acrylamide/DADMAC copolymer with about 15 to 23 mole percent monoreacted and direacted acrylamide and with about 60 to 70 mole percent total unreacted glyoxal at the target product viscosity and molecular weight. A molar ratio of 0.8 to 1 glyoxal to acrylamide results in a 95/5 mole percent acrylamide/DADMAC copolymer with about 22 to 30 mole percent monoreacted and direacted acrylamide and with about 70 to 80 mole percent total unreacted glyoxal at the target product viscosity and molecular weight. The product shelf stability depends on the storage temperature, product viscosity, total amount of reacted amide/amine, total concentration of polymer and aldehyde, the ratio of aldehyde to amide/amine functional groups and pH. Generally, the pH of the product is maintained at a low pH (2 to 3.5) and the total concentration of polymer and aldehyde is optimized to extend shelf stability. The reaction conditions are selected such that at least about 15 mole percent, preferably at least about 20 mole percent of the amino or amido groups in the polymer react with the aldehyde to form the aldehyde-functionalized polymer. The resulting aldehyde-functionalized polymers have a weight average molecular weight of at least about 100,000 g/mole, preferably at least about 300,000 g/mole. In a preferred aspect of this invention, the aldehyde functionalized polymer is an aldehyde functionalized polyamide. In another preferred aspect, the aldehyde functionalized polyamide is an aldehyde-functionalized polymer comprising 100 mole percent of one or more nonionic monomers. In another preferred aspect, the aldehyde functionalized polyamide is an aldehyde functionalized copolymer comprising about 5 to about 99 mole percent of one or more acrylamide monomers and about 95 mole percent to about 1 mole percent of one or more cationic, anionic or zwitterionic monomers, or a mixture thereof. Copolymers prepared from nonionic monomers and cationic monomers preferably have a cationic charge of about 1 to about 50 mole percent, more preferably from about 1 to about 30 mole percent. Copolymers prepared from nonionic monomers and anionic monomers preferably have an anionic charge of about 1 to about 50 mole percent, more preferably from about 1 to about 30 mole percent. Amphoteric polymers preferably have an overall positive charge. Preferred amphoteric polymers are composed of up to about 40 mole percent cationic monomers and up to about 20 mole percent anionic monomers. More preferred amphoteric polymers comprise about 5 to about 10 mole percent cationic monomers and about 0.5 to about 4 mole percent anionic monomers. Zwitterionic polymers preferably comprise 1 to about 95 mole percent, preferably 1 to about 50 mole percent zwitterionic monomers. In a preferred aspect of this invention the aldehyde-functionalized polyamide is an aldehyde functionalized copolymer comprising about 1 to about 99 mole percent of one or more acrylamide monomers and about 99 mole percent to about 1 mole percent of one or more cationic, anionic or zwitterionic monomers, or a mixture thereof. In another preferred aspect, the aldehyde functionalized polyamide is an aldehyde functionalized copolymer comprising about 50 to about 99 mole percent of one or more acrylamide monomers and about 50 to about 1 mole percent of one or more cationic monomers. In another preferred aspect, the aldehyde functionalized polymer is a copolymer comprising about 50 to about 99 mole percent of one or more acrylamide monomers and about 50 to about 1 mole percent of one or more cationic monomers wherein the copolymer is functionalized with glyoxal. In another preferred aspect, the cationic monomer is a diallyl-N,N-disubstituted ammonium halide monomer. In another preferred aspect, about 20 to about 50 mole percent of the amide groups of the copolymer have reacted with glyoxal. In another preferred aspect, the nonionic monomer is acrylamide and the diallyl-N,N-disubstituted ammonium halide monomer is diallyldimethylammonium chloride. In another preferred aspect, the functionalized polymer is a copolymer comprising about 70 to about 99 mole percent of acrylamide and about 1 to about 30 mole percent of diallyldimethylammonium chloride functionalized with glyoxal. In another preferred aspect, about 20 to about 26 mole percent of the amide groups of the copolymer have reacted with glyoxal. The aldehyde-functionalized polymers are useful for dewatering all grades of paper and paperboard with board grades and fine paper grades being preferred. Recycle board grades using OCC (old corrugated containers) with or without mixed waste have been particularly responsive. Useful increases in dewatering can be achieved with aldehyde-functionalized polymer doses in the range 0.05 to 15.0 lb polymer/ton of dry fiber with best results normally achieved in the range 0.5 to 3.0 lb/ton depending on the particular papermaking circumstances (papermachine equipment and papermaking raw materials used). The aldehyde functionalized polymers of the invention can be added in traditional wet end locations used for conventional wet end additives. These include to thin stock or thick stock. The actual wet end location is not considered to be critical, but the aldehyde-functionalized polymers are preferably added prior to the addition of other cationic additives. Because the aldehyde-functionalized polymers are believed to act as pressing aids, their addition to the wet end is not necessary, and the option of adding them just prior to the press section after the formation of the sheet can also be practiced. For example, the polymer can be sprayed on the wet web prior to entering the press section, and this can be a preferred mode of addition to reduce dosages or the effects of interferences which might occur in the wet end. Other traditional wet end additives can be used in combination with the aldehyde functionalized polymers. These include retention aids, strength additives such as starches, sizing agents, and the like. When using aldehyde-functionalized polymers as described herein having net anionic charge, a method of fixing the polymer to the fiber is needed. This fixing is typically accomplished by using cationic materials in conjunction with the polymers. Such cationic materials are most frequently coagulants, either inorganic (e.g. alum, polyaluminum chlorides, iron chloride or sulfate, and any other cationic hydrolyzing salt) or organic (e.g. p-DADMACs, EPI/DMAs, PEIs, modified PEIs or any other high charged density low to medium molecular weight polymers). Additionally, cationic materials added for other purposes like starch, wet strength, or retention additives can also serve to fix the anionic polymer. No additional additives are need to fix cationic aldehyde-functionalized polymers to the filler. The foregoing may be better understood by reference to the following examples, which are presented for purposes of illustration and are not intended to limit the scope of the invention. EXAMPLE 1 Preparation of 95/5 Mole % Acrylamide/DADMAC Copolymer To a 1500-mL reaction flask fitted with a mechanical stirrer, thermocouple, condenser, nitrogen purge tube, and addition port is added 116.4 g of deionized or soft water, 26.3 g of phosphoric acid, 63.8 g of a 62% aqueous solution of diallyldimethyl ammonium chloride (Nalco Company, Naperville, Ill.), 7.6 g of sodium formate, and 0.09 g of ethylenediaminetetraacetic acid, tetra sodium salt. The reaction mixture is stirred at 400 rpm and the pH adjusted to 4.7 to 4.9 using 17.3 g of aqueous 50% sodium hydroxide solution. The resulting mixture is heated to 100° C. and purged with nitrogen at 50 mL/min. Upon reaching 100° C., 17.6 g of a 25.0% aqueous solution of ammonium persulfate is added to the reaction mixture over a period of 135 minutes. Five minutes after starting the ammonium persulfate addition, 750.9 g of a 49.5% aqueous solution of acrylamide is added to the reaction mixture over a period of 120 minutes. The reaction is held at 100° C. for 180 minutes after ammonium persulfate addition. The reaction mixture is then cooled to ambient temperature and the pH is adjusted to 5.2 to 5.8 using 50% aqueous sodium hydroxide solution or concentrated sulfuric acid. The product is a viscous, clear to amber solution. The product has a molecular weight of about 20,000 g/mole. EXAMPLE 2 Glyoxylation of 95/5 Mole % Acrylamide/DADMAC Copolymer with 0.8 to 1 Glyoxal to Acrylamide Mole Ratio at 9.0% Actives (Total Glyoxal and Polymer) To a 2000-mL reaction flask fitted with a mechanical stirrer, thermocouple, condenser, addition port and sampling valve at the bottom of the reactor is added 238.0 g of a 41% aqueous solution of 95/5 mole % acrylamide/DADMAC copolymer, prepared as in Example 1, and 1304.0 g of deionized or soft water. The polymer solution is stirred at 400 rpm. The pH of the solution is adjusted to 8.8 to 9.1 by adding 5.8 g of 50% aqueous sodium hydroxide solution. The reaction temperature is set at 24 to 26° C. Glyoxal (143.0 g of a 40% aqueous solution) is added to the reaction mixture over 20 to 30 minutes. The Brookfield viscosity (Brookfield Programmable LVDV-II+ Viscometer, LV # 1 spindle at 60 rpm, Brookfield Engineering Laboratories, Inc, Middleboro, Mass.) of the reaction mixture is about 4 to 5 cps after glyoxal addition. The pH of the reaction mixture is adjusted to 7.5 to 8.8 using 10% aqueous sodium hydroxide (25 g) added over 20 to 30 minutes. The Brookfield viscosity (Brookfield Programmable LVDV-II+ Viscometer, LV # 1 spindle at 60 rpm, Brookfield Engineering Laboratories, Inc, Middleboro, Mass.) of the reaction mixture is about 4 to 5 cps after sodium hydroxide addition. The pH of the reaction mixture is maintained at about 7.0 to 8.8 at about 24 to 26° C. with good mixing. The Brookfield viscosity is monitored and upon achieving the desired viscosity increase of greater than or equal to 1 cps (5 to 200 cps, >100,000 g/mole) the pH of the reaction mixture is decreased to 2 to 3.5 by adding sulfuric acid (93%) to substantially decrease the reaction rate. The rate of viscosity increase is dependent on the reaction pH and temperature. The higher the pH of the reaction mixture the faster the rate of viscosity increase. The rate of viscosity increase is controlled by decreasing the pH of the reaction mixture. The product is a clear to hazy, colorless to amber, fluid with a Brookfield viscosity greater than or equal to 5 cps. The resulting product is more stable upon storage when the Brookfield viscosity of the product is less than 40 cps and when the product is diluted with water to lower percent actives. The product can be prepared at higher or lower percent total actives by adjusting the desired target product viscosity. NMR analysis of the samples prepared indicate that about 70 to 80% of the glyoxal is unreacted and 15 to 35 mole percent of the acrylamide units reacted with glyoxal to from monoreacted and direacted acrylamide. EXAMPLE 3 Dewatering Effectiveness of Representative Aldehyde-functionalized Polymers The dewatering effects of glyoxalated DADMAC/Acrylamide polymers prepared with glyoxal to acrylamide mole ratios (here after referred to as the G/A ratio) of 0.1, 0.2, 0.4 and 0.8 are evaluated through paper machine trials. The relative performance of polymers prepared using the 0.1, 0.2, and 0.8 G/A ratios are compared to the polymer prepared with the 0.4 mole ratio. The trials are run on a dual headbox Fourdrinier papermachine using 100% OCC furnish manufacturing recycle linerboard and corrugating medium. Actual papermachine conditions varied depending on the specific grade of paperboard being made. In all cases, a retention program of polyaluminum chloride fed to the thick stock and a cationic flocculant fed to the thin stock is used. For linerboard grades, ASA sizing fed to the thin stock is also present. The glyoxalated acrylamide polymers are applied through a spray boom to the underside of the top ply prior to meshing with the bottom ply, although earlier trials demonstrated the dewatering effect could also be achieved by wet-end thick or thin stock addition. The dewatering effect of the polymers is evaluated on the basis of steam pressure changes in the machine dryer section which are provided through the mills DCS (distributive control system) computer system. The sheet moisture at the reel is measured on-line and is maintained by adjustment of the steam pressure (a measure of steam usage or energy consumption). Lower sheet moisture at the reel reflects a lower sheet moisture going into the dryer section or equivalently, better dewatering through the machine sections preceding the dryer section. The lower steam demand, as measured by pressure, then reflects improved dewatering. If the steam pressure in these sections drops to a level where the operator feels comfortable that normal swings in steam demand can be handled, then he will increase the machine speed manually. When changes in polymer type or dose are made, the steam pressure from one of the steam sections is followed closely to see if any change occurs, with proper consideration given to changes in production rates when they occur. The initial effect of a drier sheet is observed by lower percent moisture detected at the reel. However, this drop in percent moisture is short lived because of the automatic regulation leaving only the steam reduction as a permanent reminder of any dewatering effect produced. Many factors other than addition of the aldehyde-functionalized polymer also affect the sheet moisture, but most, like stock changes, occur over a longer time frame than the steam reduction effect caused by the polymer additive, particularly when applied on the table through spray application. Consequently, the steam reduction is a better indicator of polymer dewatering than the average production rate or machine speed, as these measures are more easily confounded with the other factors which effect machine speed. EXAMPLE 3a Comparison of Polymer with a 0.1 G/A Ratio with Polymer Having a 0.4 G/A Ratio Comparison of these two polymers is conducted on 42 lb linerboard in the absence of wet-end starch. After a baseline is established with the 0.4 G/A ratio polymer at 2.0 lb/ton, the 0.1 G/A ratio polymer is substituted at 2.2 lb/ton. Almost immediately, the sheet at the reel is consistently observed to be wetter and the steam demand increases to maximum in about 1 hr which necessitates the re-introduction of the 0.4 G/A ratio polymer to prevent slowing down the paper machine. To regain control of the machine, 3 lb/ton of the 0.4 G/A ratio polymer is needed, and its addition results in a dramatic reduction in steam pressure, 12 psi in 15 min. Subsequently, a baseline with the 0.4 G/A ratio polymer is reestablished at 2 lb/ton whereupon substitution with 0.1 G/A ratio polymer at the higher dose of 3.4 lb/ton is initiated. At this much higher dose, the steam pressure progressively increases over a period of about an hour again to the point where it becomes necessary to revert back to the 0.4 G/A ratio polymer to prevent slowing the machine. Again, with the 0.4 G/A ratio polymer added at 3.0 lb/ton the steam pressure is quickly reduced, 12 psi in 15 min. and this reduction could be maintained even when the 0.4 G/A ratio polymer's dose is reduced to 2 lb/ton. The 0.1 G/A ratio polymer could not maintain the steam pressure, and therefore the machine speed, achieved by 0.4 G/A ratio polymer even at a dose 70% higher. No change in the strength specifications for this grade (Mullen and Scott bond) could be detected when the 0.1 G/A ratio polymer is substituted for the 0.4 G/A ratio polymer. EXAMPLE 3b Comparison of Polymer with a 0.2 G/A Ratio with Polymer Having a 0.4 G/A Ratio Comparison of these two polymers is conducted on 35 lb linerboard with 5 lb/ton wet-end starch fed to the thick stock. After a baseline is established with the 0.4 G/A ratio polymer at 2.0 lb/ton, the 0.2 G/A ratio polymer is substituted at 2.2 lb/ton. At this dosage, a modest increase in steam pressure of 5 psi is measured over a period of about the hour. Reintroduction of the 0.4 G/A ratio polymer resulted in an immediate decrease in reel moisture and a quick decline in steam pressure of 3 psi in 10 min. Switching back to the 0.2 G/A ratio polymer at 2.2 lb/ton at this point keeps the steam reasonably constant for about an hour with only a 2 psi increase. Again, reintroduction of 2 lb of the 0.4 G/A ratio polymer results in a quick decline in steam pressure of 8 psi in 20 min. indicative of improve dewatering. Based on these results, the 0.2 G/A ratio polymer certainly demonstrates dewatering ability, but even at a 10% increase in dosage, it could not maintain the pressure achievable with the 0.4 G/A ratio polymer. Additionally, unlike the 0.1 G/A ratio polymer, the 0.2 G/A ratio polymer is capable of keeping the machine running at the desired speed although at increased steam demand and dosage relative to the 0.4 G/A ratio polymer. The trial results with these three polymers indicated that the 0.4 G/A ratio polymer gives better dewatering than the 0.2 G/A ratio polymer and it in turn gives better dewatering than the 0.1 G/A ratio polymer. No change in the strength specifications for this grade (STFI) could be detected when the 0.2 G/A ratio polymer is substituted for the 0.4 G/A ratio polymer. EXAMPLE 3c Comparison of Polymer with a 0.8 G/A Ratio with Polymer having a 0.4 G/A Ratio Based on the discovery that increasing the G/A ratio in the preparation of the polymers increases dewatering, an even higher G/A ratio of 0.8 is prepared and evaluated on the same papermachine. Comparison of the 0.8 G/A ratio polymer with the 0.4 G/A ratio polymer is conducted on 33 lb corrugating medium in the absence of wet-end starch. Addition of the 0.4 G/A ratio polymer at 2.0 lb/ton results in a very good reduction in steam pressure of 21 psi after about 2 hours at which time 1.5 lb/ton of the 0.8 G/A ratio polymer replaces the 2 lb/ton of 0.4 G/A ratio polymer. Even with the 25% reduction in dose, the addition of the 0.8 G/A ratio polymer results in an even further reduction in steam pressure by 3 psi and a dramatic increase in steam pressure of 12 psi occurs in 0.5 hour when it is removed. Further trialing is conducted on 26 lb corrugating medium in the absence of wet-end starch. Starting again with 2.0 lb/ton of 0.4 G/A ratio polymer to establish the baseline, a substitution of 2.0 lb/ton of 0.8 G/A ratio polymer results in a drop in steam pressure of 7 psi in 60 min., which further decreases by 4 psi when the dosage is increased to 3 lb/ton in 10 min. Reducing the 0.8 G/A ratio polymer to only 1.0 lb/ton relative to the 3 lb/ton results in an increase in steam pressure, but it remains 8 psi below the 2.0 lb/ton 0.4 G/A ratio polymer value even with an increase in machine speed of 30 ft/min. Based on these trial results the 0.8 G/A ratio polymer appears to yield equivalent dewatering at a dose 25 to 50% less than required by the 0.4 G/A ratio polymer. The strength specification for both medium grades (Concorra) made with the 0.8 G/A ratio polymer exhibit values equal to or greater than those obtained with for the 0.4 G/A ratio polymer even though the dosages are generally lower. Based on these trial results, increasing the G/A ratio in the preparation of the aldehyde-functionalized polymers is found to provide increased dewatering activity with the preferred ratio being greater than 0.4. Changes can be made in the composition, operation and arrangement of the method of the invention described herein without departing from the concept and scope of the invention as defined in the claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>Papermaking comprises taking a slurry of papermaking raw materials at a consistency (weight percent solids) in the range 0.1 to 1.0 weight percent and dewatering it to form a sheet with a final consistency of about 95 weight percent. Paper machines accomplish this dewatering through a series of different processes which include from the beginning to end: 1) gravity or inertial dewatering (early forming section of the machine); 2) vacuum dewatering (late forming section of the machine); 3) press dewatering (press section of the machine); and 4) thermally evaporating the water (dryer section of the machine). The cost of dewatering increases in going from 1 to 4, which makes it advantageous to remove as much water as possible in the earlier stages. The rate of paper production or, equivalently, the machine speed is dictated by the rate at which the water can be removed, and consequently, any chemical treatment which can increase the rate of water removal has value for the papermaker. Many grades of paper require the use of retention aid chemicals for their manufacture in order to retain the fine particles found in the raw materials used to make the paper. It is well known in the paper industry that these retention aids can also enhance the rate of gravity, inertial, and vacuum dewatering or drainage, as it is often called. Such retention chemicals include the well known flocculants, coagulants, and microparticles used in the industry. Existing laboratory free and vacuum drainage tests can readily identify the drainage effects of these retention aid chemicals. The production rate for the vast majority of paper machines is limited by the drying capacity of the machine's dryer section. Consequently, the consistency of the paper sheet leaving the press section and going into the dryer section is most often critical in determining the paper machine speed or production rate. The effects of chemical additives on press dewatering are unclear with little information available on this topic. The effect of retention aid chemicals on press dewatering is often reported to be detrimental as a consequence of the decreased consistency entering the press as a result of increased water retention or reduction in press efficiency resulting from a loss in sheet formation. Both these factors arise from the flocculation of the papermaking particles by the retention chemicals. Because the consistency of the sheet leaving the press section is most often the most critical factor in determining machine speed, any treatment capable of increasing this consistency would obviously be highly desirable. Currently, no chemical treatments are known to be marketed as commercial press dewatering aids, although anecdotal reports suggest that some polymers can favorably effect out going press consistency. Accordingly, there is an ongoing need to develop compositions having effective press dewatering activity. Glyoxylated polyvinylamides prepared from glyoxal and polyvinylamide in a mole ratio of 0.1 to 0.2 are disclosed as wet strength resins in U.S. Pat. No. 3,556,932. Low molecular weight glyoxylated cationic polyacrylamides prepared from glyoxal and cationic polyvinylamide in a ratio of 0.1-0.5:1 are disclosed as temporary wet strength resins in U.S. Pat. No. 4,605,702. A method of imparting strength to paper by adding to a pulp slurry a mixed resin comprising an aminopolyamide-epichlorohydrin resin and a glyoxylated acrylamide-dimethyl diallyl ammonium chloride resin prepared from glyoxal and acrylamide-dimethyl diallyl ammonium chloride copolymer in a molar ratio of about 2-0.5:1 is disclosed in U.S. Pat. No. 5,674,362. | <SOH> SUMMARY OF THE INVENTION <EOH>This invention is a method of enhancing the dewatering of a paper sheet on a paper machine comprising adding to the paper sheet about 0.05 lb/ton to about 15 lb/ton, based on dry fiber, of one or more aldehyde functionalized polymers comprising amino or amido groups wherein at least about 15 mole percent of the amino or amido groups are functionalized by reacting with one or more aldehydes and wherein the aldehyde functionalized polymers have a weight average molecular weight of at least about 100,000 g/mole. detailed-description description="Detailed Description" end="lead"? | 20040126 | 20100105 | 20050728 | 78367.0 | 1 | CORDRAY, DENNIS R | METHOD OF USING ALDEHYDE-FUNCTIONALIZED POLYMERS TO ENHANCE PAPER MACHINE DEWATERING | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,764,943 | ACCEPTED | Method and system for host programmable data storage device self-testing | A method and system for providing programmable self-testing of a data storage device comprises selecting one or more host programmable tests stored in memory in the data storage device by setting data in a first log in memory of the data storage device. Parameters for execution of the one or more host programmable tests are set by setting one or more values in a second log in memory of the data storage device. The one or more host programmable tests on the data storage device are then executed. Results of the one or more host programmable tests are stored in a third log in memory of the data storage device. | 1. A method of executing one or more self-tests on a data storage device comprising: selecting one or more host programmable tests stored in memory in the data storage device by setting data in a first log in memory of the data storage device; setting parameters for execution of the one or more host programmable tests by setting one or more values in a second log in memory of the data storage device; executing the one or more host programmable tests on the data storage device; and storing results of the one or more host programmable tests in a third log in memory of the data storage device. 2. The method of claim 1, wherein one test of the one or more host programmable tests is a Position Error Signal (PES) test comprising: selecting a read/write head of the data storage device and a track of a storage medium in the data storage device to be tested, the selected track accessible by the selected read/write head; receiving a host request for servo data from the selected track; collecting PES data from the selected track while reading the requested servo data; and storing the collected PES data in a log in memory of the data storage device. 3. The method of claim 1, wherein one test of the one or more host programmable tests is a head error rate test comprising: selecting a range of addresses to be tested on a storage medium in the data storage device; collecting head error rate data for the range of addresses selected; and storing the head error rate data and a test complete status in a log in memory of the data storage device. 4. The method of claim 1, wherein one test of the one or more host programmable tests is a read verify reserve data track test comprising: performing a sector-by-sector read of reserve track data on a storage medium of the data storage device; determining whether an uncorrectable error has been detected during the sector-by-sector read of the reserve track data on the storage medium; responsive to determining one or more uncorrectable errors have been detected, storing a number of errors and an offset value for each error in a log in memory of the data storage device; and storing a test complete signal in the log in memory of the data storage device. 5. The method of claim 1, wherein one test of the one or more host programmable tests is a clear logs test comprising: determining whether a test key stored in a first log of a plurality of logs in memory of the data storage device has been set; and responsive to determining that the test key has been set, clearing all logs in the plurality of logs in memory of the data storage device and erasing the test key. 6. The method of claim 1, wherein one test of the one or more host programmable tests is an erase drive test comprising: determining whether a test key stored in a first log in memory of the data storage device has been set; determining whether an erase start address and an erase end address stored in a second log in memory of the data storage device are within a range of addresses available on the data storage device; and responsive to determining that the test key has been set and the erase start and erase end addresses are within a range of addresses available on the data storage device, erasing a storage medium of the data storage device in the range specified by the erase start and erase end addresses and erasing the test key. 7. The method of claim 1, wherein one test of the one or more host programmable tests is a rewrite test comprising: determining whether a test key stored in a first log in memory of the data storage device has been set; determining whether a rewrite start address and a rewrite end address stored in a second log in memory of the data storage device are within a range of addresses available on the data storage device; and responsive to determining that the test key has been set and the rewrite start and rewrite end addresses are within a range of addresses available on the data storage device, rewriting data on a storage medium of the data storage device with a value stored in a third log in memory of the data storage device in the range specified by the rewrite start and rewrite end addresses and erasing the test key. 8. The method of claim 1, wherein executing the one or more host programmable tests on the data storage device comprises executing the one or more host programmable tests in a captive mode. 9. The method of claim 1, wherein executing the one or more host programmable tests on the data storage device comprises executing the one or more host programmable tests in an offline mode. 10. A data storage device comprising: one or more read/write heads; a storage medium accessible by the one or more read/write heads; a processor coupled with the read/write heads to access data on the storage medium; and a memory connected with and readable by the processor and having stored therein one or more host programmable tests overwritten onto vendor specific portions of a self-monitoring program and executable by the data storage device while the data storage device is connected with a host. 11. The data storage device of claim 10, wherein the self-monitoring program is the Self-Monitoring, Analysis, and Reporting Technology (SMART) program. 12. The data storage device of claim 10, wherein one test of the one or more host programmable tests is a Position Error Signal (PES) test comprising: selecting a read/write head of the data storage device and a track of the storage medium to be tested, the selected track accessible by the selected read/write head; receiving a host request for servo data from the selected track; collecting PES data from the selected track while reading the requested servo data; and storing the collected PES data in a log in the memory. 13. The data storage device of claim 10, wherein one test of the one or more host programmable tests is a head error rate test comprising: selecting a range of addresses to be tested on the storage medium; collecting head error rate data for the range of addresses selected; and storing the head error rate data and a test complete status in a log in the memory. 14. The data storage device of claim 10, wherein one test of the one or more host programmable tests is a read verify reserve data track test comprising: performing a sector-by-sector read of reserve track data on the storage medium; determining whether an uncorrectable error has been detected during the sector-by-sector read of the reserve track data on the storage medium; responsive to determining one or more uncorrectable errors have been detected, storing a number of errors and an offset value for each error in a log in the memory; and storing a test complete signal in the log in the memory. 15. The data storage device of claim 10, wherein one test of the one or more host programmable tests is a clear logs test comprising: determining whether a test key stored in a first log of a plurality of logs in the memory has been set; and responsive to determining that the test key has been set, clearing all logs of the plurality of logs in the memory and erasing the test key. 16. The data storage device of claim 10, wherein one test of the one or more host programmable tests is an erase drive test comprising: determining whether a test key stored in a first log in the memory has been set; determining whether an erase start address and an erase end address stored in a second log in the memory are within a range of addresses available on the data storage device; and responsive to determining that the test key has been set and the erase start and erase end addresses are within a range of addresses available on the data storage device, erasing the storage medium in the range specified by the erase start and erase end addresses and erasing the test key. 17. The data storage device of claim 10, wherein one test of the one or more host programmable tests is a rewrite test comprising: determining whether a test key stored in a first log in the memory has been set; determining whether a rewrite start address and a rewrite end address stored in a second log in the memory are within a range of addresses available on the data storage device; and responsive to determining that the test key has been set and the rewrite start and rewrite end addresses are within a range of addresses available on the data storage device, rewriting data on the storage medium with a value stored in a third log in the memory in the range specified by the rewrite start and rewrite end addresses and erasing the test key. 18. The data storage device of claim 10, wherein the one or more host programmable tests are executable in a captive mode. 19. The data storage device of claim 10, wherein the one or more host programmable tests are executable in an offline mode. | FIELD OF THE INVENTION This application relates generally to data storage devices and more particularly to host programmable self-testing of a data storage device. BACKGROUND OF THE INVENTION A data storage device such as a magnetic, optical, or magneto-optical drive includes a rotating storage medium. For example, modem disc drives comprise one or more rigid discs that are coated with a magnetizable medium and mounted on the hub of a spindle motor for rotation at a constant high speed. Information is stored on the discs in a plurality of concentric circular tracks typically by an array of transducers (“heads”) mounted to a radial actuator for movement of the heads relative to the discs. Each of the concentric tracks is generally divided into a plurality of separately addressable data sectors. The read/write transducer, e.g. a magnetoresistive read/write head, is used to transfer data between a desired track and an external environment. The heads are mounted via flexures at the ends of a plurality of actuator arms that project radially outward from the actuator body. The actuator body pivots about a shaft mounted to the disc drive housing at a position closely adjacent the outer extreme of the discs. The pivot shaft is parallel with the axis of rotation of the spindle motor and the discs, so that the heads move in a plane parallel with the surfaces of the discs. The actuator arm is driven by a control signal fed to the voice coil motor (VCM) at the rear end of the actuator arm. A servo system is used to sense the position of the actuator and control the movement of the head above the disc using servo signals read from a disc surface in the disc drive. The servo system relies on servo information stored on the disc. The signals from this information generally indicate the present position of the head with respect to the disc, i.e., the current track position. The servo system uses the sensed information to maintain head position or determine how to optimally move the head to a new position centered above a desired track. The servo system then delivers a control signal to the VCM to rotate the actuator to position the head over a desired new track or maintain the position over the desired current track. With time, as these components age and wear, problems may develop in the operation of the data storage device. However, field failure analysis of these problems is sometimes difficult. While various types of test can provide accurate analysis of the problems, they typically require the device to be removed from the host for testing. Removal of the device from the host for testing can result in additional problems. For example, removing the device from the host can cause new problems or failures. Additionally, using a different interface for failure analysis may mask some problems and cause other new problems. Finally, some problems may be host specific and testable only while the device is connected to the host. Accordingly there is a need for a programmable self-test of the data storage device while the device is still connected to the host. The present invention provides a solution to this and other problems, and offers other advantages over the prior art. SUMMARY OF THE INVENTION Against this backdrop the present invention has been developed. According to one aspect of the present invention, a method of executing one or more self-tests on a data storage device comprises selecting one or more host programmable tests stored in memory in the data storage device by setting data in a first log in memory of the data storage device. Parameters for execution of the one or more host programmable tests are set in one or more values in a second log in memory of the data storage device. The one or more host programmable tests on the data storage device are then executed. Results of the one or more host programmable tests are stored in a third log in memory of the data storage device. According to another aspect of the present invention, a data storage device comprises one or more read/write heads, a storage medium accessible by the one or more read/write heads, a processor coupled with the read/write heads to access data on the storage medium, and a memory connected with and readable by the processor. The memory has stored therein one or more host programmable tests overwritten onto vendor specific portions of a self-monitoring program that are executable by the data storage device while the data storage device is connected with a host. These and various other features as well as advantages which characterize the present invention will be apparent from a reading of the following detailed description and a review of the associated drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view illustrating the primary internal components of a disc drive incorporating one of the various embodiments of the present invention. FIG. 2 is a control block diagram for the disc drive shown in FIG. 1 illustrating the primary functional components. FIG. 3 is a flowchart illustrating data storage device self-testing according to one embodiment of the present invention. FIG. 4 is a flowchart illustrating a position error signal test that may be part of the self-test illustrated in FIG. 3. FIG. 5 is a flowchart illustrating a head error rate test that may be part of the self-test illustrated in FIG. 3. FIG. 6 is a flowchart illustrating a read verify reserve track data test that may be part of the self-test illustrated in FIG. 3. FIG. 7 is a flowchart illustrating a clear logs test that may be part of the self-test illustrated in FIG. 3 FIG. 8 is a flowchart illustrating an erase drive test that may be part of the self-test illustrated in FIG. 3. FIG. 9 is a flowchart illustrating a programmable drive write test that may be part of the self-test illustrated in FIG. 3. FIG. 10 is a flowchart illustrating executing host programmable tests according to one embodiment of the present invention. DETAILED DESCRIPTION Embodiments of the present invention will be discussed with reference to a magnetic disc drive. One skilled in the art will recognize that the present invention may also be applied to any data storage device, such as an optical disc drive, a magneto-optical disc drive, or other data storage device having multiple heads for accessing data on multiple storage media. FIG. 1 is a plan view illustrating the primary internal components of a disc drive incorporating one of the various embodiments of the present invention. The disc drive 100 includes a base 102 to which various components of the disc drive 100 are mounted. A top cover 104, shown partially cut away, cooperates with the base 102 to form an internal, sealed environment for the disc drive in a conventional manner. The components include a spindle motor 106 which rotates one or more discs 108 at a constant high speed. Information is written to and read from tracks on the discs 108 through the use of an actuator assembly 110, which rotates during a seek operation about a bearing shaft assembly 112 positioned adjacent the discs 108. The actuator assembly 110 includes a plurality of actuator arms 114 which extend towards the discs 108, with one or more flexures 116 extending from each of the actuator arms 114. Mounted at the distal end of each of the flexures 116 is a head 118 which includes a fluid bearing slider enabling the head 118 to fly in close proximity above the corresponding surface of the associated disc 108. During a seek operation, the track position of the heads 118 is controlled through the use of a voice coil motor (VCM) 124, which typically includes a coil 126 attached to the actuator assembly 110, as well as one or more permanent magnets 128 which establish a magnetic field in which the coil 126 is immersed. The controlled application of current to the coil 126 causes magnetic interaction between the permanent magnets 128 and the coil 126 so that the coil 126 moves in accordance with the well-known Lorentz relationship. As the coil 126 moves, the actuator assembly 110 pivots about the bearing shaft assembly 112, and the heads 118 are caused to move across the surfaces of the discs 108. The spindle motor 106 is typically de-energized when the disc drive 100 is not in use for extended periods of time. The heads 118 are moved away from portions of the disk 108 containing data when the drive motor is de-energized. The heads 118 are secured over portions of the disk not containing data through the use of an actuator latch arrangement and/or ramp, which prevents inadvertent rotation of the actuator assembly 110 when the drive discs 108 are not spinning. A flex assembly 130 provides the requisite electrical connection paths for the actuator assembly 110 while allowing pivotal movement of the actuator assembly 110 during operation. The flex assembly includes a printed circuit board 134 to which a flex cable leading to the head is connected; the flex cable leading to the heads 118 being routed along the actuator arms 114 and the flexures 116 to the heads 118. The printed circuit board 132 typically includes circuitry for controlling the write currents applied to the heads 118 during a write operation and a preamplifier for amplifying read signals generated by the heads 118 during a read operation. The flex assembly terminates at a flex bracket 134 for communication through the base deck 102 to a disc drive printed circuit board (not shown) mounted to the bottom side of the disc drive 100. FIG. 2 is a control block diagram for a disc drive illustrating the primary functional components of a disc drive incorporating one of the various embodiments of the present invention and generally showing the main functional circuits which are resident on the disc drive printed circuit board and used to control the operation of the disc drive 100. The disc drive 100 is operably connected to a host computer 140 in a conventional manner. Control communication paths are provided between the host computer 140 and a disc drive microprocessor 142, the microprocessor 142 generally providing top level communication and control for the disc drive 100 in conjunction with programming for the microprocessor 142 stored in microprocessor memory (MEM) 143. The MEM 143 can include random access memory (RAM), read only memory (ROM) and other sources of resident memory for the microprocessor 142. The discs 108 are rotated at a constant high speed by a spindle motor control circuit 148, which typically electrically commutates the spindle motor 106 (FIG. 1) through the use, typically, of back electromotive force (BEMF) sensing. During a seek operation, wherein the actuator 110 moves the heads 118 between tracks, the position of the heads 118 is controlled through the application of current to the coil 126 of the voice coil motor 124. A servo control circuit 150 provides such control. During a seek operation the microprocessor 142 receives information regarding the velocity of the head 118, and uses that information in conjunction with a velocity profile stored in memory 143 to communicate with the servo control circuit 150, which will apply a controlled amount of current to the voice coil motor coil 126, thereby causing the actuator assembly 110 to be pivoted. Data is transferred between a host computer 140 or other device and the disc drive 100 by way of an interface 144, which typically includes a buffer to facilitate high speed data transfer between the host computer 140 or other device and the disc drive 100. Data to be written to the disc drive 100 is thus passed from the host computer 140 to the interface 144 and then to a read/write channel 146, which encodes and serializes the data and provides the requisite write current signals to the heads 118. To retrieve data that has been previously stored in the data storage device 100, read signals are generated by the heads 118 and provided to the read/write channel 146, which performs decoding and error detection and correction operations and outputs the retrieved data to the interface 144 for subsequent transfer to the host computer 140 or other device. Stored in memory 143 may be a self-monitoring program such as the Self-Monitoring, Analysis, and Reporting Technology (SMART) feature set. This, and similar programs, monitor a variety of parameters of the data storage device during normal operation. These programs contain a number of vendor specific extensions or tests that are not typically used after manufacture of the device. Additionally, these self-monitoring programs utilize a number of easily accessible memory locations or logs that may be used to store information. Generally, embodiments of the present invention utilize the vendor specific portions of these self-monitoring programs and logs to provide host programmable self-test. FIG. 3 is a flowchart illustrating data storage device self-testing according to one embodiment of the present invention. Here, processing begins with determination operation 305. Determination operation 305 comprises selecting and programming boundary parameters of one or more host programmable tests provided with the data storage device. That is, the supplier of the data storage device determines which host programmable tests will be made available on the device to be executable by the data storage device while the data storage device is connected with a host. When executed, the user, via the host with which the data storage device is connected, can select one or more of the test to be executed as well as setting parameters for the execution of those tests. In one example, the type of test to be preformed may be indicated by the user setting data in a log in the memory of the data storage device. Additionally, setting parameters for execution of the one or more host programmable tests may be done by the user setting one or more values in a second log in memory of the data storage device. Examples of these tests will be discussed below with reference to FIGS. 4-9. Host programmable tests that may be available include, but are not limited to, a Position Error Signal (PES) test, a head error rate test, a read verify reserve track data test, and others as will be discussed below. Control then passes to query operation 310. Query operation 310 comprises determining the mode of operation the selected tests shall be executed in. In some devices, tests may be executed in two modes of operation, such as offline and captive. If at query operation 310 a determination is made that the test mode is captive mode, control passes to execute operation 320. Execute operation 320 comprises executing the selected tests in a captive mode. In captive mode, tests are executed while host-initiated commands are ignored until the data storage device has completed all selected tests. Control then passes to log operation 330. If, at query operation 320, a determination is made that the test mode is not captive mode, control passes to execute operation 325. Execute operation 325 comprises executing the selected tests in an offline mode. In offline mode tests can be executed and data collected when the data storage device is not servicing host-initiated commands. Control then passes to log operation 330. Log operation 330 comprises writing the data collected during execution of the selected tests to the appropriate vendor specific logs. For example, the self-monitoring program stored in memory in the data storage device may be the Self-Monitoring, Analysis, and Reporting Technology (SMART) program or another similar program. SMART provides a number of vendor specific tests that are not used after manufacture of the device as well as a number of logs stored in the memory of the device. The host programmable tests may be overwritten on these vendor specific tests. Additionally, as will be seen below, the logs may be used to store control information and results for the host programmable tests. FIG. 4 is a flowchart illustrating a Position Error Signal (PES) test that may be part of the self-test illustrated in FIG. 3. In this example, processing begins with select operation 405. Select operation 405 comprises selecting a read/write head of the data storage device and a track of a storage medium in the data storage device to be tested where the selected track is accessible by the selected read/write head. Control then passes to receive operation 410. Receive operation 410 comprises receiving a host request for servo data from the selected track. That is, through the host, a tester may request one or more servo sectors of the storage medium to be read and tested. Control the passes to read operation 415. Read operation 415 comprises collecting PES data from the selected track while reading the requested servo data. In some cases, the PES data may be calculated as a percentage off-track value for the head and track being tested. Control then passes to store operation 420. Store operation 420 comprises storing the collected PES data in a log in memory of the data storage device. That is, the collected PES data may be stored in a log such as the SMART logs where it can be accessed via the host or another means. FIG. 5 is a flowchart illustrating a head error rate test that may be part of the self-test illustrated in FIG. 3. Processing begins with select operation 505. Select operation 505 comprises selecting a range of addresses to be tested on a storage medium in the data storage device. For example, a starting and ending address, such as a Logical Block Address (LBA), may be specified. In some cases, these addresses may be set by the tester in logs, such as SMART logs, in the memory of the data storage device. Control then passes to read operation 510. Read operation 510 comprises collecting head error rate data for the range of addresses selected. That is, as data is read from the storage medium between the starting and ending addresses, error rate information is collected. Control then passes to store operation 515. Store operation 515 comprises storing the head error rate data and a test complete status in a log in memory of the data storage device. That is, the collected error rate data may be stored in a log such as the SMART logs where it can be accessed via the host or another means. FIG. 6 is a flowchart illustrating a read verify reserve track data test that may be part of the self-test illustrated in FIG. 3. Here, processing begins with read operation 605. Read operation 605 comprises performing a sector-by-sector read of reserve track data on a storage medium of the data storage device. Control then passes to query operation 610. Query operation 610 comprises determining whether an uncorrectable error has been detected during the sector-by-sector read of the reserve track data on the storage medium. If a determination is made that no uncorrectable errors have been detected, control passes to store operation 615. If, however, a determination is made that one or more uncorrectable errors have been detected, control passes to store operation 620. Store operation 620 comprises storing a number of errors and an offset value for each error. That is, the collected error data may be stored in a log such as the SMART logs where it can be accessed via the host or another means. Control passes to store operation 615. Store operation comprises storing a test complete signal in a log in memory of the data storage device. That is, the test complete signal may be stored in a log such as the SMART logs where it can be accessed via the host or another means. FIG. 7 is a flowchart illustrating a clear logs test that may be part of the self-test illustrated in FIG. 3. In this example, processing begins with query operation 705. Query operation 705 comprises determining whether a test key stored in a first log of a plurality of logs in memory of the data storage device has been set. That is, since this function is destructive of information in the logs, a key is used to verify the intention to perform this function. The key may be in the form of a flag or other information such as a password stored in the logs by the tester. If, at query operation 705, a determination is made that the test key has not been set, no further processing is performed. If, however, a determination is made that the test key has been properly set, control passes to set operation 710. Set operation 710 comprises clearing all logs of the plurality of logs in memory of the data storage device. That is, all logs in the data storage device memory, such as SMART logs, are cleared. Control then passes to erase operation 715. Erase operation 715 comprises erasing the test key. Once again, since the clear logs function is destructive, the key will be erased after use to prevent accidental re-execution of the function. FIG. 8 is a flowchart illustrating an erase drive test that may be part of the self-test illustrated in FIG. 3. Processing begins with query operation 805. Query operation 805 comprises determining whether a test key stored in a first log in memory of the data storage device has been set. That is, since this function is destructive of information on the storage medium, a key is used to verify the intention to perform this function. The key may be in the form of a flag or other information such as a password stored in the logs by the tester. If, at query operation 805, a determination is made that the test key has not been set, no further processing is performed. If, however, a determination is made that the test key has been properly set, control passes to query operation 810. Query operation 810 comprises determining whether an erase start address and an erase end address stored in a second log in memory of the data storage device are within a range of addresses available on the data storage device. That is, an erase start address and an erase end address, perhaps in the form of an LBA, may be stored in the logs in the memory of the data storage device. These addresses are checked to determine whether they are valid addresses for the data storage device. If the erase start address and the erase end address stored in the second log in memory of the data storage device are not within a range of addresses available on the data storage device, no further processing is performed. However, if the start and end addresses are within the range of available addresses, control passes to erase operation 815. Erase operation 815 comprises erasing the storage medium of the data storage device in the range specified by the erase start and erase end addresses. Control then passes to erase operation 820. Erase operation 820 comprises erasing the test key. Once again, since the erase function is destructive, the key will be erased after use to prevent accidental re-execution of the function. FIG. 9 is a flowchart illustrating a programmable rewrite test that may be part of the self-test illustrated in FIG. 3. Here, processing begins with query operation 905. Query operation 905 comprises determining whether a test key stored in a first log in memory of the data storage device has been set. That is, since this function is destructive of information on the storage medium, a key is used to verify the intention to perform this function. The key may be in the form of a flag or other information such as a password stored in the logs by the tester. If, at query operation 905, a determination is made that the test key has not been set, no further processing is performed. If, however, a determination is made that the test key has been properly set, control passes to query operation 910. Query operation 910 comprises determining whether a rewrite start address and a rewrite end address stored in a second log in memory of the data storage device are within a range of addresses available on the data storage device. That is, a rewrite start address and a rewrite end address, perhaps in the form of an LBA, may be stored in the logs in the memory of the data storage device. These addresses are checked to determine whether they are valid addresses for the data storage device. If the erase start address and the erase end address stored in a log in memory of the data storage device are not within a range of addresses available on the data storage device, no further processing is performed. However, if the start and end addresses are within the range of available addresses, control passes to rewrite operation 915. Rewrite operation 915 comprises rewriting data on a storage medium of the data storage device with a value stored in a third log in memory of the data storage device in the range specified by the rewrite start and rewrite end addresses. That is, the tester may set a rewrite pattern in the logs in memory of the data storage device. This pattern will then be rewritten to all data located between the starting and ending addresses. Control then passes to erase operation 920. Erase operation 920 comprises erasing the test key. Once again, since the rewrite function is destructive, the key will be erased after use to prevent accidental re-execution of the function. FIG. 10 is a flowchart illustrating executing host programmable tests according to one embodiment of the present invention. Here, processing begins with select operation 1005. Select operation 1005 comprises selecting one or more host programmable tests stored in memory in the data storage device by setting data in a first log in memory of the data storage device. That is, the tester may select one or more of the host programmable tests but setting a flag or other data in a specific log in the memory. Control then passes to set operation 1010. Set operation 1010 comprises setting parameters for execution of the one or more host programmable tests by setting one or more values in a second log in memory of the data storage device. In other words, the tester sets parameters such as a test key, starting address, ending address, and other parameters discussed above in the logs. Control then passes to execute operation 1015. Execute operation 1015 comprises executing the one or more host programmable tests on the data storage device. Control then passes to read operation 1020. Read operation 1020 comprises retrieving results of the one or more host programmable tests from a third log in memory of the data storage device. That is, the tester, through the host or by another means, reads the test results saved in the logs as indicated above. It will be clear that the present invention is well adapted to attain the ends and advantages mentioned as well as those inherent therein. While a presently preferred embodiment has been described for purposes of this disclosure, various changes and modifications may be made which are well within the scope of the present invention. For example, a self-monitoring program other than SMART may be used to provide host programmable tests. Additionally, more, fewer, or different tests than those discussed herein may be made available as host programmable tests. Numerous other changes may be made which will readily suggest themselves to those skilled in the art and which are encompassed in the spirit of the invention disclosed and as defined in the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>A data storage device such as a magnetic, optical, or magneto-optical drive includes a rotating storage medium. For example, modem disc drives comprise one or more rigid discs that are coated with a magnetizable medium and mounted on the hub of a spindle motor for rotation at a constant high speed. Information is stored on the discs in a plurality of concentric circular tracks typically by an array of transducers (“heads”) mounted to a radial actuator for movement of the heads relative to the discs. Each of the concentric tracks is generally divided into a plurality of separately addressable data sectors. The read/write transducer, e.g. a magnetoresistive read/write head, is used to transfer data between a desired track and an external environment. The heads are mounted via flexures at the ends of a plurality of actuator arms that project radially outward from the actuator body. The actuator body pivots about a shaft mounted to the disc drive housing at a position closely adjacent the outer extreme of the discs. The pivot shaft is parallel with the axis of rotation of the spindle motor and the discs, so that the heads move in a plane parallel with the surfaces of the discs. The actuator arm is driven by a control signal fed to the voice coil motor (VCM) at the rear end of the actuator arm. A servo system is used to sense the position of the actuator and control the movement of the head above the disc using servo signals read from a disc surface in the disc drive. The servo system relies on servo information stored on the disc. The signals from this information generally indicate the present position of the head with respect to the disc, i.e., the current track position. The servo system uses the sensed information to maintain head position or determine how to optimally move the head to a new position centered above a desired track. The servo system then delivers a control signal to the VCM to rotate the actuator to position the head over a desired new track or maintain the position over the desired current track. With time, as these components age and wear, problems may develop in the operation of the data storage device. However, field failure analysis of these problems is sometimes difficult. While various types of test can provide accurate analysis of the problems, they typically require the device to be removed from the host for testing. Removal of the device from the host for testing can result in additional problems. For example, removing the device from the host can cause new problems or failures. Additionally, using a different interface for failure analysis may mask some problems and cause other new problems. Finally, some problems may be host specific and testable only while the device is connected to the host. Accordingly there is a need for a programmable self-test of the data storage device while the device is still connected to the host. The present invention provides a solution to this and other problems, and offers other advantages over the prior art. | <SOH> SUMMARY OF THE INVENTION <EOH>Against this backdrop the present invention has been developed. According to one aspect of the present invention, a method of executing one or more self-tests on a data storage device comprises selecting one or more host programmable tests stored in memory in the data storage device by setting data in a first log in memory of the data storage device. Parameters for execution of the one or more host programmable tests are set in one or more values in a second log in memory of the data storage device. The one or more host programmable tests on the data storage device are then executed. Results of the one or more host programmable tests are stored in a third log in memory of the data storage device. According to another aspect of the present invention, a data storage device comprises one or more read/write heads, a storage medium accessible by the one or more read/write heads, a processor coupled with the read/write heads to access data on the storage medium, and a memory connected with and readable by the processor. The memory has stored therein one or more host programmable tests overwritten onto vendor specific portions of a self-monitoring program that are executable by the data storage device while the data storage device is connected with a host. These and various other features as well as advantages which characterize the present invention will be apparent from a reading of the following detailed description and a review of the associated drawings. | 20040126 | 20060509 | 20050728 | 79045.0 | 1 | FIGUEROA, NATALIA | METHOD AND SYSTEM FOR HOST PROGRAMMABLE DATA STORAGE DEVICE SELF-TESTING | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,764,992 | ACCEPTED | Shaft clamping arrow rest | An arrow rest comprises an arrow rest support arm pivotally mounted to the riser of a bow. The support arm is coupled to a cable guide of the bow through linkage that causes the support arm to rise relative to the riser of the bow as the cable is drawn to launch an arrow. As the cable is released to launch an arrow, the arrow rest drops to allow the fletching to pass the arrow rest without contact. In addition, as the arrow rest moves from a first resting position to a second pre-launch position and back again, a clamping mechanism grasps the shaft of the arrow when the support arm is in the resting position. As the support arm moves to the pre-launch position, the clamping mechanism releases the shaft of the arrow so that the arrow can be freely launched from the support arm without interference from the clamping mechanism. | 1-54. (canceled) 55. An apparatus for supporting an arrow relative to a bow, comprising: a mounting bracket configured for attaching to a bow; an arrow rest coupled to said mounting bracket being movable relative thereto between a first position and a second position, said arrow rest supporting a shaft of an arrow relative thereto when said arrow rest is in said first and said second positions; an arrow retaining member extending over said arrow rest for retaining the shaft of the arrow relative to said arrow rest when said arrow rest is in said first position; and a linkage mechanism coupled to said arrow rest and for coupling to a cable of a bow for actuating said arrow rest upon movement of the cable of the bow. 56. The apparatus of claim 55, further comprising a shaft rotatably coupled to the mounting bracket and attached to the arrow rest. 57. The apparatus of claim 56, further comprising a pivotable member fixedly attached to said shaft and coupled to said linkage mechanism whereby movement of said linkage mechanism causes rotation of said pivotable member and rotation of said shaft relative to said mounting bracket. 58. The apparatus of claim 57, wherein said arrow rest and said pivotable member are on opposite sides of said mounting bracket. 59. The apparatus of claim 55, further including a biasing member for biasing said arrow rest relative to said mounting bracket. 60. The apparatus of claim 55, wherein said arrow rest defines a channel for at least partially receiving the shaft of the arrow. 61. The apparatus of claim 60, wherein said arrow retaining member is configured to cooperate with said arrow rest for holding the shaft of the arrow relative to said arrow rest when said arrow rest is in said first position. 62. The apparatus of claim 55, wherein said arrow retaining member comprises a clamping member having a first portion for holding the shaft of an arrow and a second portion for engaging with an abutment surface to return said elongate member to a clamping position as said arrow rest moves between said first and second positions. 63. The apparatus of claim 62, wherein said clamping member is biased relative to said arrow rest to an open position so as to automatically open when said arrow rest moves to said second position. 64. The apparatus of claim 57, wherein said linkage mechanism comprises a linkage member coupled between said pivotable member and a cable bracket. 65. The apparatus of claim 55, wherein said linkage mechanism comprises a cable coupled to a biasing member for providing bias in said cable. 66. The apparatus of claim 65, further including a cable adjustment mechanism for adjusting the effective length of the cable. 67. An apparatus for supporting an arrow relative to a bow, comprising: a mounting structure configured for coupling to the riser of a bow; a rotatable shaft coupled to said mounting structure; an arrow support structure coupled to said rotatable shaft and being pivotable upon rotation of said rotatable shaft between a first position and a second position; an arrow retaining member extending over said arrow support structure for holding the arrow relative to the arrow support structure when said arrow support structure is in said first position; and a linkage mechanism for coupling the rotatable shaft to a cable of the bow to cause movement of said arrow support structure between said first position and said second position upon movement of the cable of the bow. 68. The apparatus of claim 67, further comprising a pivotable member fixedly attached to said shaft and coupled to said linkage mechanism whereby movement of said linkage mechanism causes rotation of said pivotable member and rotation of said shaft relative to said mounting structure. 69. The apparatus of claim 68, wherein said arrow support structure and said pivotable member are on opposite sides of said mounting structure. 70. The apparatus of claim 67, further including a biasing member for biasing said pivotable member relative to said mounting structure. 71. The apparatus of claim 67, wherein said arrow support structure defines a channel for at least partially receiving and supporting an arrow. 72. The apparatus of claim 71, wherein said arrow retaining member is configured to cooperate with the channel of the arrow support structure for retaining the arrow relative to the arrow support structure. 73. The apparatus of claim 67, wherein said arrow retaining member comprises a first portion for holding an arrow and a second portion for engaging with an abutment surface to return said arrow retaining member to a clamping position. 74. The apparatus of claim 73, wherein said arrow retaining member is biased relative to said arrow support structure to automatically release the arrow when said arrow support structure moves to said second position. 75. The apparatus of claim 68, wherein said linkage mechanism comprises a linkage member coupled between said pivotable member and a cable of a bow. 76. The apparatus of claim 75, wherein said linkage member is resilient. 77. The apparatus of claim 68, wherein said linkage mechanism comprises a linkage member coupled between said pivotable member and a cable bracket. 78. The apparatus of claim 67, wherein said linkage mechanism comprises a cable coupled to a biasing member for providing bias in said cable. 79. An apparatus for supporting an arrow relative to a bow, comprising: a mounting member for coupling to a bow; an arrow rest coupled to said mounting bracket being movable relative thereto between a first resting position and a second position, said arrow rest configured for supporting a shaft of an arrow relative thereto and for preventing the shaft of the arrow from falling from said at least one arrow rest when said arrow rest is in said first resting position; and a linkage mechanism coupled between said arrow rest and a cable of a bow for actuating said arrow rest between said first resting position and said second position. 80. The apparatus of claim 79, wherein said arrow rest further comprises a shaft retaining member coupled to said arrow rest and extending over the shaft of the arrow when said arrow rest is in said first resting position. 81. The apparatus of claim 79, further comprising an elongate shaft rotatably coupled to the mounting member and attached to the arrow rest whereby rotation of said elongate shaft causes pivotal movement of said arrow rest relative to said mounting member. 82. The apparatus of claim 79, wherein movement of said linkage mechanism causes vertical movement of said arrow rest relative to said mounting member. 83. The apparatus of claim 80, further comprising a pivotable member fixedly attached to said shaft and coupled to said linkage mechanism whereby movement of said linkage mechanism causes rotation of said pivotable member and rotation of said shaft relative to said mounting member. 84. The apparatus of claim 83, wherein said arrow rest and said pivotable member are on opposite sides of said mounting member. 85. The apparatus of claim 83, further including a biasing member for biasing said pivotable member relative to said mounting member. 86. The apparatus of claim 79, wherein said arrow rest defines a channel for receiving the shaft of the arrow. 87. The apparatus of claim 80, wherein said shaft retaining member comprises a clamping portion for holding the shaft of the arrow relative to said arrow rest. 88. The apparatus of claim 80, wherein said shaft retaining member is biased relative to said arrow rest to an open position so as to automatically open when said arrow rest moves to said second position. 89. The apparatus of claim 80, wherein said shaft retaining member releases the shaft of the arrow when said arrow rest is in said second position. 90. The apparatus of claim 83, wherein said linkage mechanism comprises a linkage member coupled between said pivotable member and a cable bracket. 91. The apparatus of claim 79, wherein said linkage mechanism comprises a cable. | BACKGROUND 1. Field of the Invention The present invention relates to an apparatus for supporting the shaft of an arrow when launched from an archery bow. More particularly, the present invention relates to an arrow rest that can move from a first, resting position to a second ready position as the sting of the bow is drawn to a firing position. In the resting position, the arrow rest holds the shaft of the arrow relative to the arrow rest. In the ready position, the arrow rest supports the shaft of the arrow but no longer clamps the shaft of the arrow to allow the arrow to freely launch from the arrow rest. 2. Description of the Prior Art Over the past few decades, the interest in the sport of archery in the United States has significantly increased. In particular, the number of sportsmen and sportswomen who hunt using a bow has continued to rise. As a result of this growth, the number of archery products manufacturers and the development of new archery products has greatly expanded. For many years, recurve bows were the only kind of bow available. Once the compound bow was introduced, the interest in and, naturally, the number of accessories for compound bows increased. Such accessories include various types of sighting apparatuses, stabilizing devices, vibration dampening device and arrow rests for supporting the shaft of the arrow when an arrow is drawn prior to launching. The first arrow rests typically comprised a V-shaped tab of plastic that was attached to the riser of the bow. With such devices, the shaft of the arrow rests within the V of the arrow rest while the archer aims the bow toward a target. It was discovered that the friction between the shaft of the arrow and the arrow rest and/or the contact between the arrow rest and the feathers or fletching on the aft end of the arrow can effect the trajectory and direction of flight of the arrow. To address this problem, many arrow rests are formed from a flexible material, such as plastic. By using a flexible material, the arrow rest can deflect out of the way when the arrow is launched from the bow. Such a plastic arrow rest, however, has its drawbacks. For example, the plastic tab arrow rest typically deflects in a direction transverse to the direction of flight of the arrow. As such, contact between the fletching of an arrow and the arrow rest can still effect the flight of the arrow. In order to provide a more stable support for an arrow and to allow the arrow rest to flex away from the shaft in the direction of the flight of the arrow, arrow rests have been developed that include a pair of arms. The tips of the arms support the shaft of the arrow. The arms are typically attached to or integrally formed with a rotatable shaft that is rotatably mounted to a mounting bracket. The mounting bracket is configured for attachment to the riser of a compound bow. In addition, the shaft is biased relative to the mounting bracket so that the arms are biased toward the shaft of an arrow when the arrow is resting upon the tips of the arms. The biasing of the arms is provided by a coil spring interposed between the mounting bracket and the rotatable shaft. When an arrow is launched from a bow utilizing such an arrow rest, the impact of the fletching of the arrow upon the arms of the arrow rest will cause the arms to rotate downwardly. After the fletching pass the arms, the coil spring then causes the arms to rotate back to their pre-launch position. This contact between the fletching and the arrow rest can effect the trajectory of the arrow by applying drag, and/or torque to the shaft of the arrow as the arrow is released. Muzzy Products Corp. in Georgia has attempted to provide an arrow rest that eliminates the effects of the arrow rest on the flight of the arrow. In the Muzzy device, the arrow rest lifts the shaft of the arrow to a pre-shoot position at full draw and falls away as the arrow is released. The arrow rest rises from a resting position to a pre-launch position by being coupled between the riser and the cable slide. The arrow rest is coupled between the riser and the cable slide with a pair of arms that are pivotally connected to one another and to the riser and cable slide. As the bow is drawn to a pre-launch position sliding the cable guide along the cable guard away from the riser, the pair of arms straighten relative to one another. As the pair of arms straighten, the arrow rest rises relative to the riser. When the arrow is released, the action of the cable causes the cable guide to slide back to its resting position. The movement of the cable guide back to its original position causes the arrow rest to drop. Another example of a “fall-away” arrow rest is manufactured by Trophy Taker of Montana. The arrow rest is coupled to the riser and tide with a tether to the cable of the bow. The arrow rest is actuated from a resting position to a pre-launch position at full draw by the pull on the tether generated by the cable. As tension is applied to the tether, the arrow rest is caused to be rotated from a first position to a second position that raises the shaft of the arrow. As the arrow is released, the tension on the tether is removed and the arrow rest is allowed to drop by rotation of the arrow rest relative to the riser. Such fall-away arrow rests, while attempting to resolve some of the problems caused by arrow rests, do not address a significant disadvantage of all arrow rests. When an archer draws an arrow along the arrow rest, one hand grasps the grip of the bow and the other draws the cable. The shaft of the arrow rests on the arrow rest but is otherwise unsupported along its length. As most arrow rests provide a V-shaped notch for supporting the shaft of the arrow or a pair of arms whose tips support the shaft therein between, any sudden movement of the bow can cause the shaft of the arrow to fall from the arrow rest. Often times, such the shaft of the arrow falls from the arrow rest when an archer has pulled the cable to a full draw, but decides to controllably return the cable to its resting position without launching the arrow. Because of the jerking force of such a maneuver, the archer is often unable to maintain the shaft of the arrow on the arrow rest. As the arrow falls, it may impact the riser of the bow generating a noise that can startle game. In a hunting setting, noise is a major factor in the ability to stalk an animal. Hunters take great strides to maintain silence in the wild so as to not startle the game. As most hunters will attest, the “clanking” of the shaft of a falling arrow against the riser is sure to startle most game causing the animal to flee. The Muzzy device attempts to address this issue by providing a relatively large V for supporting the shaft of the arrow. Even with the Muzzy device, however, an archer is not likely to be able to move through underbrush with a loaded arrow without the arrow falling from the arrow rest. Another example of an arrow rest that prevents the shaft of the arrow from falling from the arrow rest is comprised of a cylindrical aperture supporting a plurality of inwardly extending bristles that form a small opening in the center of the bristles for supporting the shaft of the arrow. As the arrow is launched, the fletching can pass through the bristles. The bristles, however, tend to tear the fletching from the shaft of the arrow. Thus, it would be advantageous to provide an arrow rest that is capable of grasping the shaft of the arrow when the arrow is at a resting position and freely supporting the shaft of the arrow when the bow is at full draw. It would also be advantageous to provide such an arrow rest that falls away as the arrow is launched to eliminate effects of the arrow rest on the flight and/or fletching of the arrow. SUMMARY OF THE INVENTION These and other advantages will become apparent from a reading of the following summary of the invention and description of the illustrated embodiments in accordance with the principles of the present invention. Accordingly, an arrow rest comprises an arrow rest support arm pivotally mounted to the riser of a bow. The support arm is coupled to the cable guide of the bow through linkage that causes the support arm to rise relative to the riser of the bow as the cable is drawn to launch an arrow. As the cable is released to launch an arrow, the arrow rest drops to allow the fletching to pass the arrow rest without contact. As the arrow rest moves from a first resting position to a second pre-launch position and back again, the support arm is provided with a clamping mechanism that grasps the shaft of the arrow when the support arm is in the resting position. As the support arm moves to the pre-launch position, the clamping mechanism releases the shaft of the arrow so that the arrow can be freely launched from the support arm without interference from the clamping mechanism. As the cable is released and the cable guide returns to its resting position, the support arm also returns to its resting position. As the support arm moves from the pre-launch position to the resting position, the clamping mechanism closes relative to the support arm so as to be able to grasp the shaft of an arrow. The clamping mechanism is comprised of a flexible or rigid material that allows the shaft of an arrow to be inserted into the clamping mechanism while it is in a closed position. The clamping mechanism, however, prevents the shaft of the arrow from being dislodged from the clamping mechanism until the cable of the bow is drawn an amount sufficient to open the clamping mechanism. The clamping mechanism may be actuated by contacting the shelf of the riser or an overdraw shelf as a secondary shelf such that the clamping mechanism closes upon contacting the shelf. The clamping mechanism is biased into an open position so that as the clamping mechanism rises relative to the shelf of the riser, the clamping mechanism automatically opens. Likewise, the clamping mechanism may be actuated by gear-type arrangements that cause the clamping mechanism to open and close around the shaft. It is also contemplated that the shaft of the arrow may be removed from the clamping mechanism by a secondary arrow rest support that rises to remove the shaft of the arrow from the clamping mechanism as the cable is drawn. BRIEF DESCRIPTION OF THE DRAWINGS The foregoing summary, as well as the following detailed description of the illustrated 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 several exemplary embodiments which illustrate what is currently considered to be the best mode for carrying out the invention, it bing understood, however, that the invention is not limited to the specific methods and instruments disclosed. In the drawings: FIG. 1A is a partial front view of a compound bow with a first embodiment of an arrow rest attached thereto in accordance with the principles of the present invention; FIG. 1B is a partial first side view of the compound bow and arrow rest shown in FIG. 1A; FIG. 1C is a partial second side view of the compound bow and arrow rest shown in FIG. 1A; FIG. 2A is an end view of a first embodiment of a clamping arrow rest in a first resting position in accordance with the present invention; FIG. 2B is an end view of the clamping arrow rest shown in FIG. 2A in a second pre-launch position; FIG. 3 is a cross-sectional side view of an arrow rest support arm in accordance with the principles of the present invention; FIG. 4 is a partial front view of a compound bow with a second embodiment of an arrow rest attached thereto in accordance with the principles of the present invention; FIG. 5 is a partial front view of a compound bow with a third embodiment of an arrow rest attached thereto in accordance with the principles of the present invention; FIG. 6A is a partial side view of a compound bow with a fourth embodiment of an arrow rest attached thereto in accordance with the principles of the present invention; FIG. 6B is a front view of the clamping mechanism of the arrow rest illustrated in FIG. 6A. FIG. 7 is a side view of a second embodiment of a cable guide assembly in accordance with the principles of the present invention; FIG. 8 is a side view of a third embodiment of a cable guide assembly in accordance with the principles of the present invention; FIG. 9 is a side view of a fifth embodiment of an arrow rest in accordance with the principles of the present invention; FIG. 10 is a side view of the linkage mechanism of the arrow rest shown in FIG. 9; FIG. 11 is a top view of the cable slide of the arrow reset shown in FIG. 9; FIG. 12 is a cross-sectional side view of the cable slide shown in FIG. 11; FIG. 13 is a side view of a component of the linkage mechanism shown in FIG. 10; FIG. 14 is a top view of the linkage mechanism component shown in FIG. 13; FIG. 15 is an alternative embodiment of a means for linking the arrow rest of the present invention to the cable system of a bow in accordance with the principles of the present invention; FIG. 16A is an front view of a sixth embodiment of an arrow rest in accordance with the principles of the present invention; and FIG. 16B is a front view of the arrow rest of FIG. 16A in a raised position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, FIG. 1A illustrates a compound bow, generally indicated at 10, to which an arrow rest assembly, generally indicated at 20 is, is attached. The compound bow comprises a typical bow assembly having a riser 12 and an upper limb 14 to which an upper pulley or cam is rotatably attached. A cable 18 is provided for launching an arrow (not shown). It should be noted, however, that while the bow 10 is illustrated as having a particular configuration, the arrow rest 20 of the present invention could be adapted to be attached to and function with any compound bow in the art as well as those developed in the future. The riser 12 of the bow 10 defines a laterally offset portion 22 through which the arrow is launched. The offset portion 22 allows the cable 18 to be in generally vertical alignment with the limb 14 and the remainder of the riser 12 while providing a channel or window to allow positioning of an arrow therein while maintaining proper alignment of the arrow relative to the cable 18 for launching. The arrow rest 20 is positioned within the offset portion 22 of the riser 12 so as to hold the arrow in proper alignment with the cable 18. The arrow rest 20 is comprised of a mounting bracket 24 mounted to the riser 12 of the bow 10. A rotatable shaft 26 is coupled to the mounting bracket 24 and attached to a pivotable member 28. The pivotable member 28 is linked to the cable guide (not visible) such that movement of the cable guide causes pivoting of the pivotable member 28 and corresponding rotation of the rotatable shaft 26. The pivotable member 28 is biased relative to the mounting bracket 24 as with coil spring 30 attached to post 32. An arrow rest support arm 34 is attached to the shaft 26 such that rotation of the shaft 26 causes the support arm 34 to pivot. The pivotable member 28 is biased in a direction that forces the support arm 34 toward the shelf 36 of the riser. The arrow rest 20 is provided with a clamping member 40 that is coupled to the support arm 34. In the resting position as shown, the clamping member 40 extends over the support arm so as to clamp the shaft of an arrow relative to the support arm 34. The clamping member 40 can rotate relative to the support arm 34 about its attachment point 42. As further illustrated in FIG. 1B, the mounting bracket 24 extends behind the riser 12 and is fixedly attached thereto. The support arm 34 is pivotally coupled to the mounting bracket 24 with the rotatable shaft 26 that fits within the arm 35 and is rigidly held relative thereto with a set screw 43. As the pivotable member 28 pivots relative to the mounting bracket rotating the rotatable shaft 26, the arm 34 to rises off of the shelf 36 from a resting position as shown to a pre-launch position above the shelf 36. The arm 34 is comprised of a first arm portion 44 that may be formed of a rigid material such as metal or a harder plastic and a second portion 46 that may be formed from a softer material such as rubber or a softer plastic. The first portion 44 provides structural support for the second portion and is capable of resisting damage from the forces encountered by the returning to or being present at the resting position. The shaft of an arrow rests on the second portion 46. Because the arm 34 returns to its resting position as the arrow is launched, it is not necessary to form the second portion 46 from a friction limiting material such as TEFLON or the like. That is, because the arrow does not slide to any substantial degree along the second portion 46 as the arrow is launched, it is not necessary to form the second portion 46 from a slick material as is commonly used on other types of arrow rests known in the art that maintain contact with the shaft of the arrow as the arrow is launched. The clamping member 40 forms part of a clamping mechanism for grasping the shaft of the arrow when the arrow rest is in the resting position. As the arm 34 is lifted, the clamping member 40 opens to release the shaft of the arrow. Whether launched or simply controllably returned to the resting position, the engagement of the clamping member 40 with the shelf 36, or more particularly with a clamping member abutment structure 48, causes the clamp to close relative to the second portion 46. Because the clamping member 40 is formed from a flexible material such as a softer plastic or rubber material, the shaft of an arrow can be inserted between the clamping member 40 and the second portion 46 by slightly flexing open the clamping member 40 to allow passage of the shaft of an arrow therein. Actuation of the arrow rest 20 is controlled by coupling or linking the arrow rest 20 to the cable slide 50. The cable slide 50 is commonly found on compound bows but is primarily used to position the cable spans 52 and 53 from lying in the same vertical plane as the primary cable portion 54 that is used to launch an arrow. That is, the cable spans 53 and 54 are moved to one side or offset from the vertical plane defined between the primary cable portion 54 and the arrow rest 20 so as to provide clearance for the shaft and fletching of an arrow. The cable slide 50 slides along a cable guide 56 that is rigidly secured relative to the riser 12. The cable guide 56 is comprised of an elongate shaft attached to the mounting bracket 24. In a typical compound bow, the cable guide 56 is attached directly to the riser 12 at a position above the vertical location of the arrow rest relative to the riser. By moving it to the mounting bracket, the cable slide 50 is positioned in alignment with the arrow rest 20 for allowing a substantially horizontal linkage between the arrow rest and the cable slide 50. As the primary cable portion 54 is drawn, the cable slide 50 will move in the direction of the arrow 58 toward the proximal end 60 of the cable guide 56. That is, as the cable portion 54 is pulled away from the riser 12, the end of the limb 14 containing the pulley 16 will flex away from the riser 12 causing the cable spans 52 and 53 to also move away from the riser 12 so as to maintain their vertical orientation between the upper and lower pulleys or cams. By linking the pivotable member 28 to the cable slide 50 at a position spaced from its center of rotation, the movement of the slide 50 away from the riser will cause a corresponding rotation of the pivotable member 28. Also, because there is tension between the pivotable member 28 in a direction toward the riser 12 a cable slide stop 62 is provided on the cable guide 56. The cable stop 62 properly position the cable slide 50 relative to the cable guide 50 so as to maintain substantial vertical alignment of the cable spans 52 and 53, that is without pulling the cable spans 52 and 53 toward the riser 12, when the cable 18 is returned to a resting position as shown. As shown in FIG. 1C, the pivotable member 28 is rotatably coupled to the mounting bracket 24 with the rotatable shaft 26. The shaft 26 is fixedly held relative to the pivotable member 28 with a set screw 62 that spans a slot 64 defined by the pivotable member 28. The shaft 26 can rotate relative to the mounting bracket 24 as by passing through a transversely extending bore through the mounting bracket 24 that may be lined with a plastic or other type of bushing or bearing surface to allow free rotation of the shaft 26 relative to the mounting bracket 24. Of course, in a simpler version, the shaft could be integrally formed with the pivotable member by forming an L-shaped member with one leg of the L-shaped member rotatably coupled to the mounting bracket 24 and the other leg pivoted to rotate the first leg. The pivotable member 28 is linked to the cable slide 50 with a biasing member 66. The cable slide 50 is provided with a pair of slots 63 and 65 for receiving and laterally engaging with the cable spans 52 and 53. Thus, the cable slide 50 moves along the cable guide 56 as the cable spans 52 and 53 move away from the riser 12 as the cable is drawn. The biasing member is held relative to the pivotable member 28 and the cable slide 50 by engagement with a pair of posts 68 and 70 or threaded fasteners with an exposed portion for wrapping of the biasing member 66. In this embodiment, the biasing member 66 is comprised of an elastic cord that allows for a certain amount of stretching of the cord before becoming taut. This amount of stretch provides a slight delay in the actuation of the pivotable member 28 relative to movement of the cable slide 50. This allows for a small amount of pre-draw to be placed on the cable without causing actuation of the clamping mechanism of the arrow rest 20. This also causes the clamping mechanism to return to its resting position before the cable returns to its resting position as the arrow is launched. That is, the arrow rest 20 returns to the resting position ahead of the cable to allow the arrow rest to move out of the way as the fletching of the arrow passes the arrow rest 20. A second biasing member 30 is coupled between the post 68 and a second post 72 or threaded fastener secured to the mounting bracket 24. The second biasing member 30 is provided to cause the arm 34 to move to the resting position as shown when the cable slide 50 is also in the resting position. The second biasing member may be comprised of one or more coil springs that engage the posts 68 and 72 to create a bias between the mounting bracket 24 and the pivotable member 28. The spring force of the second biasing member is configured to be greater than the spring force of the first biasing member 66 so as to pull the first biasing member 66 and the cable slide 50 toward the riser 14 as the cable is released when launching an arrow. As the cable slide 50, however, returns to its resting position, the first biasing member 66 returns to its stretchable state while maintaining some amount of tension between the pivotable member 28 and the cable slide 50 without overpowering the second biasing member 30. The second biasing member 30 also provides an additional benefit to the ballistics of the bow itself. That is, the biasing force applied by the second biasing member 30 through the first biasing member when it is taut to the cable slide 50 increases the firing speed of the bow. Thus, the bow will actually shoot an arrow at a higher velocity with the arrow rest 20 of the present invention. Referring now to FIGS. 2A and 2B, the distal end of an clamping arrow rest, generally indicated at 100, in accordance with the principles of the present invention shown in a first resting position (FIG. 2A) and a second pre-launch position (FIG. 2B) relative to the shelf 102 of the bow riser. The arrow rest 100 is comprised of a base portion 104 for supporting the shaft of an arrow (not shown) and a pivotable camping member 106 that is rotatably coupled to the base portion 104 and biased relative to the base portion 104 in a direction to encourage rotation of the clamping member 106 from its position shown in FIG. 2A to its position in FIG. 2B. The base portion defines a longitudinally extending slot 108 in the form of a V for supporting the shaft of an arrow. A projected portion 110 extends from the distal end 112 of the base portion 108 so as to provide an abutment surface 114 for engaging with a surface 118 of the clamping member 106 to prevent over rotation of the clamping member 106 relative to the base portion 104. The clamping member 106 is comprised of an arcuate clamping portion 120 a bulbous shaped abutment portion 122 and an attachment portion 124 having a bore extending there through for attachment to the base potion 104. An abutment member 126 is attached to the shelf 102 for abutting the abutment portion 122 as the arrow rest 100 moves from its pre-launch position back to the resting position to cause the clamping member 106 to from an open position back to a closed/grasping position. As shown in FIG. 2A. The rounded surface 128 of the clamping member 106 slides along the abutment member 126 as the arrow rest 100 drops. When the clamping member 106 is positioned relative to the abutment member 126 as shown in FIG. 2A, the clamping member 106 is “locked” in place such that manual rotation of the clamping member 106 is prevented by the abutment member 126. By forming the clamping member 106 from a flexible material such as a rubber or plastic, the gap 130 between the clamping portion 120 ad the base 104 can be increased to allow manual insertion of removal of a shaft of an arrow without having to rotate the clamping member 106 relative to the base 104. The clamping portion 120, however, is rigid enough to hold the shaft of an arrow in the channel 108 and help prevent the arrow shaft from becoming inadvertently disengaged from the arrow rest 100. Also, by facing the gap 130 toward the surface of the riser (FIG. 1A), if the shaft of an arrow does become dislodged from the clamping member 106, the arrow will likely fall between the arrow rest 100 and the riser without falling to the ground. FIG. 3 is a cross-sectional side view of an arrow rest arm, generally indicated at 150 in accordance with the principles of the present invention. The arm 150 includes an elongate attachment member 152 defining an aperture 154 for receiving a shaft for rotation of the arm 150 relative thereto. The attachment member 152 is attached to an arrow supporting member 156 that is slid onto the distal end 158 of the arm 152. The arrow supporting member 156 provides a longitudinally extending channel or slot 159 within which the shaft of an arrow can at least partially reside therein. A clamping member 162 is coupled to the supporting member 156 with a threaded fastener 164 that extends through the clamping member 162 and threadedly engages the arm 152. A biasing member 166, such as a coil spring, is positioned on the shaft of the threaded fastener 164 and biases the clamping member 162 relative to the supporting member 156. to encourage clamping of the shaft of an arrow relative to the supporting member 156. FIG. 4 illustrates another embodiment of an arrow rest, generally indicated at 200 configured for clamping the shaft of an arrow (not shown) relative thereto and releasing the shaft of the arrow when the arrow is in a position to be launched. The actuation of the arrow rest 200 is provided by a mechanism configured similarly to that shown in FIG. 1A, that is by rotation of a shaft 202 to cause pivotal rotation of the arrow rest arm 204 relative thereto. In this embodiment, however, the arrow rest is provided with a clamping member 206 that is actuated by a rack 208 and pinion gear 210 that engages with gear teeth 212 provided on the clamping member 206. The pinion gear 210 is an idle gear (i.e., freely rotatable) that is coupled to the arm 204 and moves therewith. The rack 208 is attached to the riser 214 and may be positioned at a slight angle to match the angular rotation of the pinion gear 210 as it pivots upwardly with the arm 204. As the pinion gear 210 is lifted the pinion gear 210 will rotate relative to the rack 208 causing the clamping member 206 to open. As the pinion gear 210 moves down the rack 208, the engagement with the teeth 212 on the clamping member 206 will cause the clamping member 206 to become closed as illustrated. Thus, both opening and closing of the clamping member 206 is actuated by the pinion gear 210. Of course, those of skill in the art will appreciate after understanding the principles of the present invention that many other mechanisms may be employed to provide a clamping feature relative to the arrow rest for grasping the shaft of an arrow when the arrow is in a resting position. The present invention in intended to cover each and every variation of the present invention and equivalents thereof. For example, as shown in FIG. 5, the clamping arrow rest, generally indicated at 300 is comprised of a pair of scissor type clamping members 302 and 304 that define a central aperture 306 therein between for receiving an holding the shaft of an arrow. As such, each clamping member 302 and 304 defines a crescent shaped recess 308 and 310, respectively, for engaging the sides of the shaft of an arrow. The clamping members 302 and 304 are biased relative to one other in a direction that encourages separation of the recesses 308 and 310. In addition, the clamping member 302 and 304 can rotate relative to each other about a central shaft 312. A biasing device 314, such as a coil spring, is provide on the shaft 312 to bias the clamping members 302 and 304 into an open position. The clamping member 302 is provided with a recess 316 that defines and abutment surface 318 for abutting against the arcuate surface 320 of the clamping member 304. When the surface 320 is engaged against the surface 318, the clamping members 302 and 404 are in an open position. The surface 322 and 324 then define a V-shaped notch for supporting the shaft of an arrow. As the arrow rest returns to a resting position in which the legs of the clamping members 302 and 304 engage the shelf 326 of the riser 328, the curved surfaces of the legs, such as surface 320, slide along the shelf 326 until the bases of the surface 322 and 324 abut to hold the clamping members slightly apart as shown. In FIG. 6A, an arrow rest, generally indicated at 400, is caused to pivot as indicated by arrows 401 and 402 about a rotatable shaft 404. An arrow rest arm 406 is attached to the shaft 404. The arm 406 extends on both sides of the shaft 404. A shaft support 408 is attached to the distal end 410 of the arm 406 and defines a channel 412 for supporting the shaft 414 of an arrow 416. A clamping device 420 is attached to the proximal end 422 of the arm 406. As shown in FIG. 6B, the clamping device 420 is a C shaped member when turned on its side to define a partially enclosed central aperture 424 for receiving the shaft 414 of an arrow 416. The base 426 of the device 420 is provided with a pair of bores 428 and 430 for receiving threaded fasteners to attach the device 420 to the distal end 422 of the arm 406. A similar means of attachment may be employed for attaching the shaft support 408 to the proximal end 410. A pair of crescent shaped arms portions 432 and 434 further define the aperture 424 and are spaced apart at their tips to allow insertion and removal of the shaft 414 of the arrow 416 while securing the shaft 414 in the aperture 424 to prevent the shaft 414 from simply falling out if the device 420 becomes inverted. The device 420 is formed from a soft flexible material such as rubber, foam rubber or foam. As the arrow rest arm 406 rotates in the direction of arrows 401 and 402, the shaft support 408 will lift the shaft 414 relative the to the shelf 438 of the riser. As the shaft 414 is lifted and the clamping device 420 lowers, the shaft 414 will be pulled from engagement with clamping device 420 to be free to be launched. When the arrow 416 is released, the arm 406 is biased to return the support 408 to engage the shelf 438 as shown. The rotation of the arm 406, however, is timed so as to allow the fletching (not shown) of the arrow 416 to pass by the clamping device 420 before the clamping device 420 moves back to a position where it may impact the fletching as it passes the clamping device 420. Finally, as shown in FIG. 7 and FIG. 8, the arrow rest (as previously described) may be coupled to a cable slide with various linkage devices that provide some delay in actuation of the arrow rest relative to movement of the cable slide as an arrow is drawn. As previously discussed, such delay, while not essential, allows the arrow rest to move out of the way of the arrow before the fletching of the arrow passes the arrow rest. In FIG. 7, the cable slide 500 is provided with a mounting portion 502 that defines a transversely extending bore 504. A cable 506 (which is coupled to the arrow rest) is secured with a cable stop 508 that is crimped to the end of the cable 506. The stop 508 is inserted into a coupling device 510 that defines a recess for holding the stop 508 therein and a threaded bore on the other end for receiving a threaded fastener 512. The fastener 512 is provided with a coil spring 514 that biases the head of the fastener 512 relative to the mounting portion 502. The fastener 512 extends through the bore 504 and into the coupler 510. As the cable slide 500 slides along the cable guide 516 in the direction of the arrow, the spring 514 will be compressed to some degree before the cable 506 is moved, thus providing the aforementioned delay. Similarly, in FIG. 8, a cable slide 600 is coupled to a cable 602 with a linkage mechanism 604 that includes a threaded fastener 606 inserted through a mounting portion 608 of the cable slide 600 and engages an internally threaded tube-like member 610. The distal end 612 of the tube 610 is inwardly turned to provide an abutment surface for holding a spring 614 disposed around a threaded shaft 616. A nut 618 is threaded onto the proximal end of the shaft 616 and can be adjusted to any point along the shaft to allow for adjustability of the linkage mechanism 604 for the particular bow configuration. The shaft 616 is threaded into a coupler 620 having a similar configuration to the coupler 510 shown in FIG. 7. As the cable slide 600 moves to apply tension in the cable 602, the spring 614 allows for movement of the slide 600 and the tube 610 before the cable 602 is moved along with movement of the cable slide 600. FIG. 9 illustrates yet another embodiment of a self-clamping arrow rest, generally indicated at 700, in accordance with the present invention. The arrow rest 700 is comprised of a mounting bracket 702 for mounting the arrow rest 700 relative to the riser of a bow (not shown). A cable guide 704 is attached to the bracket 702. A cable slide 706 for receiving the tuning cables of a compound bow is positioned on and slidable relative to the cable guide. The cable slide 706 is coupled to an adjustable linkage member 708 that is comprised of first and second components 710 and 712 that can be pinned or otherwise fastened together at discrete points to allow for adjustment of the length of the linkage member 708. The linkage member 708 is also coupled at its opposite end to a pivotable member 714 that is rotatably coupled to the bracket 702 by an elongate shaft 716 that extends through the bracket 702 and is rotatable relative thereto. On the other side of the bracket 702 from the pivotable member 714, an arrow rest arm 718 is attached to the shaft 716. The arrow rest arm 718 includes a clamping/shaft support assembly 720 that is configured to grasp the shaft of an arrow when the arm 718 is in a resting position and to release the shaft of the arrow when the arm 718 is raised. A biasing member 722 in the form of a coil spring is interposed and connected between the mounting bracket 702 and the pivotable member 714 so as to encourage rotation of the shaft 716 in a counter-clockwise direction and thus downward biasing of the support assembly 720. The pivotable member 714 is provided with an arm portion 724 having a plurality of attachment points thereon in the form of holes for allowing selective attachment at discrete points of the linkage member 708 relative thereto. A rubber stop 726 is positioned on the cable guide 704 to allow the cable slide 706 to abut there against when the tuning cables are in a resting position. As further illustrated in FIG. 10, the first and second components 710 and 712 of the linkage member 708 are provided with a plurality of holes, such as holes 728 and 730, to allow for selective attachment of the two components as with fasteners 732 and 734. The distal end 736 of the linkage member 708 fits within the cable slide 706, and as will be described further, provides a delay as the linkage member 708 can move or slide as indicated by the arrow relative to the cable slide 706 a certain distance within the slot or channel 756 without causing corresponding movement of the cable slide 706 until it abuts the end 760 of the channel 756. At that point, the cable slide 706 will move with the linkage member 708. In a resting position, the linkage member 708 with be positioned within the channel 756 away from the end 760. As the cable of the bow is drawn, the cable slide 706 can move away from the linkage member 708 a distance to cause a delayed reaction in movement between the cable slide 706 and the linkage member 708 until the end 736 of the linkage member 708 abuts the end 760 of the channel 756. This provides the proper timing for bow stroke. As further illustrated in FIG. 11, the cable slide is comprised of a cable retention portion 740 integrally formed with a linkage maintaining portion 742. The cable retention portion 740 is provided with two channels 744 and 746 for retaining and holding the tuning cables relative thereto. Each channel 744 and 746 has an L shape so as to help maintain the tuning cables therein. A transversely extending bore 748 is provided for receiving the cable guide 704. The linkage maintaining portion 742 is defined by a pair of side walls 750 and 752 held relative to one another by a connecting portion 754. The side walls 750 and 752 define opposing channels 756 and 758, respectively. As shown in FIG. 12, the channel 756 extends partially along the side wall 750 so as to terminate therein to define an abutment end 760. A rubber stopper 762 is positioned on the opposite end of the abutment end 760 so as to retain the end of the linkage member 708 therein. As shown in FIGS. 13 and 14, one component 710 of the linkage member 708 is comprised of an elongate member having a cylindrical end portion 764 that extends laterally outwardly from the component 710. The end portion 764 includes a pair of cylindrical protrusions 765 and 767 laterally extending therefrom configured for being slidably received within the channels 756 and 758. Moreover, the spacing between the side walls 750 and 752 is such that the cylindrical portion protrusions 765 and 767 are held therein when inserted. Because of the length of the channels 756 and 758 relative to the diameter of the portions 765 and 767, the portions 765 and 767 can slide a distance along the channels 756 and 758 to allow movement of the cable slide 706 relative to the component 710 before the portion 764 engages with the end 760 such that further movement of the cable slide 706 will cause corresponding movement of the linkage 708. Such delay in movement of the linkage 708 relative to the cable slide 706 requires a certain amount of draw on the cable of the bow before the arm 718 raises and the clamping assembly releases the shaft of the arrow. Furthermore, at release of the arrow, the delay allows the arrow to become airborne before dropping away to allow the fletching or vanes of the arrow pass the arrow rest without contacting the clamping/support assembly 720. While the apparatus of the present invention has been described with reference to certain embodiments to illustrate what is believed to be the best mode of the invention, it is contemplated that upon review of the present invention, those of skill in the art will appreciate that various modifications and combinations may be made to the present embodiments without departing from the spirit and scope of the invention as recited in the claims. For example, as shown in FIG. 15 the arrow rest could be linked to one of the cable spans without using the cable slide by attaching the linkage mechanism 802 directly to the cable 800. Thus, a bracket or clamping device 804 fastened around the cable 800 could be attached directly to the cable 800 with the linkage mechanism 802 attached to the bracket or clamping device 804. Thus, the cable guide need not be attached to the mounting bracket and the arrow rest of the present invention can work independently of the cable guide and/or cable slide. In another example as shown in FIGS. 16A and 16B, the clamping mechanism 900 of the arrow rest according to the principles of the present invention is comprised of a single piece member 902 formed from a flexible material, such as rubber or plastic. The member 902 defines an shaft grasping recess 904 for grasping the shaft 906 of an arrow when the member 902 is in contact with the riser shelf 908 or other abutment of a bow. The member includes a pair of legs 910 and 912 separated by a thinned portion 914 that functions essentially as a hinge between the two leg portions 910 and 912. As the member 902 is lifted from the shelf 908, the leg portions 910 and 912 are drawn together by the natural biasing force of the material from which the member 902 is formed. That is, the member 902 is formed to be shaped as shown in FIG. 16B and is forced into its shape shown in FIG. 16A by contact with the shelf 908. Thus, as the bottoms of the leg portions 910 and 912 contact the shelf 908, the legs are caused to spread apart which in turn causes the recess 904 to close around the shaft 906. The bottoms of the leg portions 910 and 912 are rounded to encourage the legs to spread when contacting the shelf 908. The opening of the top of the recess 904 is such that the shaft 906 can be inserted into the recess 904 when the arrow rest 900 is in the position shown in FIG. 16A. Once inserted into the recess 904, the shaft 906 is held within the recess 904 by the top edges of the recess 904. With some effort, however, the shaft 906 can be removed from the recess 904 if desired. As the member 902 moves from the position shown in FIG. 16A to the position shown in FIG. 16B, the arrow member opens the recess 904 to cradle the shaft 906 without obstructing its ability to be launched by the bow from the arrow rest 900. The claims provided herein are intended to cover such modifications and combinations and all equivalents thereof. Reference herein to specific details of the illustrated embodiments is by way of example and not by way of limitation. | <SOH> BACKGROUND <EOH>1. Field of the Invention The present invention relates to an apparatus for supporting the shaft of an arrow when launched from an archery bow. More particularly, the present invention relates to an arrow rest that can move from a first, resting position to a second ready position as the sting of the bow is drawn to a firing position. In the resting position, the arrow rest holds the shaft of the arrow relative to the arrow rest. In the ready position, the arrow rest supports the shaft of the arrow but no longer clamps the shaft of the arrow to allow the arrow to freely launch from the arrow rest. 2. Description of the Prior Art Over the past few decades, the interest in the sport of archery in the United States has significantly increased. In particular, the number of sportsmen and sportswomen who hunt using a bow has continued to rise. As a result of this growth, the number of archery products manufacturers and the development of new archery products has greatly expanded. For many years, recurve bows were the only kind of bow available. Once the compound bow was introduced, the interest in and, naturally, the number of accessories for compound bows increased. Such accessories include various types of sighting apparatuses, stabilizing devices, vibration dampening device and arrow rests for supporting the shaft of the arrow when an arrow is drawn prior to launching. The first arrow rests typically comprised a V-shaped tab of plastic that was attached to the riser of the bow. With such devices, the shaft of the arrow rests within the V of the arrow rest while the archer aims the bow toward a target. It was discovered that the friction between the shaft of the arrow and the arrow rest and/or the contact between the arrow rest and the feathers or fletching on the aft end of the arrow can effect the trajectory and direction of flight of the arrow. To address this problem, many arrow rests are formed from a flexible material, such as plastic. By using a flexible material, the arrow rest can deflect out of the way when the arrow is launched from the bow. Such a plastic arrow rest, however, has its drawbacks. For example, the plastic tab arrow rest typically deflects in a direction transverse to the direction of flight of the arrow. As such, contact between the fletching of an arrow and the arrow rest can still effect the flight of the arrow. In order to provide a more stable support for an arrow and to allow the arrow rest to flex away from the shaft in the direction of the flight of the arrow, arrow rests have been developed that include a pair of arms. The tips of the arms support the shaft of the arrow. The arms are typically attached to or integrally formed with a rotatable shaft that is rotatably mounted to a mounting bracket. The mounting bracket is configured for attachment to the riser of a compound bow. In addition, the shaft is biased relative to the mounting bracket so that the arms are biased toward the shaft of an arrow when the arrow is resting upon the tips of the arms. The biasing of the arms is provided by a coil spring interposed between the mounting bracket and the rotatable shaft. When an arrow is launched from a bow utilizing such an arrow rest, the impact of the fletching of the arrow upon the arms of the arrow rest will cause the arms to rotate downwardly. After the fletching pass the arms, the coil spring then causes the arms to rotate back to their pre-launch position. This contact between the fletching and the arrow rest can effect the trajectory of the arrow by applying drag, and/or torque to the shaft of the arrow as the arrow is released. Muzzy Products Corp. in Georgia has attempted to provide an arrow rest that eliminates the effects of the arrow rest on the flight of the arrow. In the Muzzy device, the arrow rest lifts the shaft of the arrow to a pre-shoot position at full draw and falls away as the arrow is released. The arrow rest rises from a resting position to a pre-launch position by being coupled between the riser and the cable slide. The arrow rest is coupled between the riser and the cable slide with a pair of arms that are pivotally connected to one another and to the riser and cable slide. As the bow is drawn to a pre-launch position sliding the cable guide along the cable guard away from the riser, the pair of arms straighten relative to one another. As the pair of arms straighten, the arrow rest rises relative to the riser. When the arrow is released, the action of the cable causes the cable guide to slide back to its resting position. The movement of the cable guide back to its original position causes the arrow rest to drop. Another example of a “fall-away” arrow rest is manufactured by Trophy Taker of Montana. The arrow rest is coupled to the riser and tide with a tether to the cable of the bow. The arrow rest is actuated from a resting position to a pre-launch position at full draw by the pull on the tether generated by the cable. As tension is applied to the tether, the arrow rest is caused to be rotated from a first position to a second position that raises the shaft of the arrow. As the arrow is released, the tension on the tether is removed and the arrow rest is allowed to drop by rotation of the arrow rest relative to the riser. Such fall-away arrow rests, while attempting to resolve some of the problems caused by arrow rests, do not address a significant disadvantage of all arrow rests. When an archer draws an arrow along the arrow rest, one hand grasps the grip of the bow and the other draws the cable. The shaft of the arrow rests on the arrow rest but is otherwise unsupported along its length. As most arrow rests provide a V-shaped notch for supporting the shaft of the arrow or a pair of arms whose tips support the shaft therein between, any sudden movement of the bow can cause the shaft of the arrow to fall from the arrow rest. Often times, such the shaft of the arrow falls from the arrow rest when an archer has pulled the cable to a full draw, but decides to controllably return the cable to its resting position without launching the arrow. Because of the jerking force of such a maneuver, the archer is often unable to maintain the shaft of the arrow on the arrow rest. As the arrow falls, it may impact the riser of the bow generating a noise that can startle game. In a hunting setting, noise is a major factor in the ability to stalk an animal. Hunters take great strides to maintain silence in the wild so as to not startle the game. As most hunters will attest, the “clanking” of the shaft of a falling arrow against the riser is sure to startle most game causing the animal to flee. The Muzzy device attempts to address this issue by providing a relatively large V for supporting the shaft of the arrow. Even with the Muzzy device, however, an archer is not likely to be able to move through underbrush with a loaded arrow without the arrow falling from the arrow rest. Another example of an arrow rest that prevents the shaft of the arrow from falling from the arrow rest is comprised of a cylindrical aperture supporting a plurality of inwardly extending bristles that form a small opening in the center of the bristles for supporting the shaft of the arrow. As the arrow is launched, the fletching can pass through the bristles. The bristles, however, tend to tear the fletching from the shaft of the arrow. Thus, it would be advantageous to provide an arrow rest that is capable of grasping the shaft of the arrow when the arrow is at a resting position and freely supporting the shaft of the arrow when the bow is at full draw. It would also be advantageous to provide such an arrow rest that falls away as the arrow is launched to eliminate effects of the arrow rest on the flight and/or fletching of the arrow. | <SOH> SUMMARY OF THE INVENTION <EOH>These and other advantages will become apparent from a reading of the following summary of the invention and description of the illustrated embodiments in accordance with the principles of the present invention. Accordingly, an arrow rest comprises an arrow rest support arm pivotally mounted to the riser of a bow. The support arm is coupled to the cable guide of the bow through linkage that causes the support arm to rise relative to the riser of the bow as the cable is drawn to launch an arrow. As the cable is released to launch an arrow, the arrow rest drops to allow the fletching to pass the arrow rest without contact. As the arrow rest moves from a first resting position to a second pre-launch position and back again, the support arm is provided with a clamping mechanism that grasps the shaft of the arrow when the support arm is in the resting position. As the support arm moves to the pre-launch position, the clamping mechanism releases the shaft of the arrow so that the arrow can be freely launched from the support arm without interference from the clamping mechanism. As the cable is released and the cable guide returns to its resting position, the support arm also returns to its resting position. As the support arm moves from the pre-launch position to the resting position, the clamping mechanism closes relative to the support arm so as to be able to grasp the shaft of an arrow. The clamping mechanism is comprised of a flexible or rigid material that allows the shaft of an arrow to be inserted into the clamping mechanism while it is in a closed position. The clamping mechanism, however, prevents the shaft of the arrow from being dislodged from the clamping mechanism until the cable of the bow is drawn an amount sufficient to open the clamping mechanism. The clamping mechanism may be actuated by contacting the shelf of the riser or an overdraw shelf as a secondary shelf such that the clamping mechanism closes upon contacting the shelf. The clamping mechanism is biased into an open position so that as the clamping mechanism rises relative to the shelf of the riser, the clamping mechanism automatically opens. Likewise, the clamping mechanism may be actuated by gear-type arrangements that cause the clamping mechanism to open and close around the shaft. It is also contemplated that the shaft of the arrow may be removed from the clamping mechanism by a secondary arrow rest support that rises to remove the shaft of the arrow from the clamping mechanism as the cable is drawn. | 20040126 | 20050927 | 20050120 | 63514.0 | 2 | RICCI, JOHN A | SHAFT CLAMPING ARROW REST | SMALL | 1 | CONT-ACCEPTED | 2,004 |
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