Patents by Inventor Jagdish C. Tandon
Jagdish C. Tandon has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 5031032Abstract: A color chip construction especially adapted for use in fabricating full width arrays in which the individual chip photosites consisting of a blue, green, and red photodiode shaped and positioned to provide a rectangular photosite with square sides that enhance butting of the color chip with other like color chips to form full width color arrays.Type: GrantFiled: March 30, 1990Date of Patent: July 9, 1991Assignee: Xerox CorporationInventors: Alain E. Perregaux, Jagdish C. Tandon, Josef E. Jedlicka
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Patent number: 5029020Abstract: A scanner-printer of the type that scans and prints in blocks, each block consisting of a preset number of image lines, in which the block of lines scanned by the scanning array is larger than the block of lines printed by a printing array so that there is provided additional image scan lines before and after each block of image lines printed, the additional image scan lines providing image context data for use in processing image signals adjacent the boundaries between blocks of image lines.Type: GrantFiled: November 17, 1989Date of Patent: July 2, 1991Assignee: Xerox CorporationInventors: Paul D. Norder, Jagdish C. Tandon, Ying-wei Lin, Anthony F. Calarco
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Patent number: 4860075Abstract: An image sensor array and method of fabrication which facilitates replacement of a defective one in a series of arrays butted together to form a longer scanning array in which a (110) silicon wafer having a row of photosites has separation lines etched thereon by orientation dependent etching along the (111) planes, with the separation lines for the opposite ends of the array each consisting of first and second partial boundary lines longitudinally offset from one another connected by a third boundary line so that the ends of the array have a has a generally L-shaped offset permitting bi-directional separating and aligned inserting movement when replacing a defective array.In a second embodiment, the arrays are formed on (100) silicon with alternating `nail` head and `mesa` head shapes to facilitate removal and replacement of a defective array.Type: GrantFiled: January 1, 1989Date of Patent: August 22, 1989Assignee: Xerox CorporationInventors: Mehdi N. Araghi, Jagdish C. Tandon
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Patent number: 4830985Abstract: An image sensor array and method of fabrication which facilitates replacement of a defective one in a series of arrays butted together to form a longer scanning array in which a (110) silicon wafer having a row of photosites has separation lines etched thereon by orientation dependent etching along the (111) planes, with the separation lines for the opposite ends of the array each consisting of first and second partial boundary lines longitudinally offset from one another connected by a third boundary line so that the ends of the array have a has a generally L-shaped offset permitting bi-directional separating and aligned inserting movement when replacing a defective array.In a second embodiment, the arrays are formed on (100) silicon with alternating `nail` head and `mesa` head shapes to facilitate removal and replacement of a defective array.Type: GrantFiled: April 16, 1987Date of Patent: May 16, 1989Assignee: Xerox CorporationInventors: Mehdi N. Araghi, Jagdish C. Tandon
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Patent number: 4761683Abstract: A scanner system for detecting images on a surface and generating an electronic representation thereof for transmission to an image processing system, including at least first, second and third rows of n sensors generating charges representative of detected light of preselected wavelengths during an integration period of a selected duration. Each row of sensors is comprised of substantially similar construction, and suitable for detection of a preselected wavelength, Sensors may be chosen from a sensor type which facilitates transfer of charges through the sensor.Type: GrantFiled: December 18, 1986Date of Patent: August 2, 1988Assignee: Xerox CorporationInventors: Ronald G. Matteson, Jagdish C. Tandon
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Patent number: 4737854Abstract: A linear image sensor array with a row of photodiodes and a transfer circuit for each photodiode, the circuit having a pair of transistors for two stage transfer of the image signal charge from the photodiode to the gate of one transistor of a two transistor source follower, a transistor for applying a bias charge to the photodiode, a multiplexing transistor for connecting the source follower output to an output line, a reset transistor for resetting the source follower, and clock signals for operating the transfer circuits in succession to serially output image signals to the output line.Type: GrantFiled: July 18, 1986Date of Patent: April 12, 1988Assignee: Xerox CorporationInventors: Jagdish C. Tandon, Pierre A. Lavallee
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Patent number: 4735671Abstract: A method and apparatus for fabricating long full width scanning arrays for reading or writing images. For this purpose, smaller scanning arrays are assembled in abutting end-to-end relationship, each of the smaller arrays being provided with a pair of V-shaped locating grooves in the face thereof. An aligning tool having predisposed pin-like projections insertable into the locating grooves on the smaller scanning arrays upon assembly of the smaller arrays with the aligning tool is used to mate a series of the smaller arrays in end-to-end abutting relationship, there being discretely located vacuum ports in the aligning tool to draw the smaller arrays into tight face-to-face contact with the tool. A suitable base is then affixed to the aligned arrays and the aligning tool withdrawn.Type: GrantFiled: March 26, 1987Date of Patent: April 5, 1988Assignee: Xerox CorporationInventors: James C. Stoffel, Jagdish C. Tandon
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Patent number: 4712018Abstract: A method and apparatus for fabricating long full width scanning arrays for reading or writing images. For this purpose, smaller scanning arrays are assembled in abutting end-to-end relationship, each of the smaller arrays being provided with a pair of V-shaped locating grooves in the face thereof. An aligning tool having predisposed pin-like projections insertable into the locating grooves on the smaller scanning arrays upon assembly of the smaller arrays with the aligning tool is used to mate a series of the smaller arrays in end-to-end abutting relationship, there being discretely located vacuum ports in the aligning tool to draw the smaller arrays into tight face-to-face contact with the tool. A suitable base is then affixed to the aligned arrays and the aligning tool withdrawn.Type: GrantFiled: March 26, 1987Date of Patent: December 8, 1987Assignee: Xerox CorporationInventors: James C. Stoffel, Jagdish C. Tandon
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Patent number: 4712137Abstract: A high density charge coupled device imaging array 88 with a bilinear array of photosites on a single integrated circuit chip is utilized in an image scanning configuration. Offset photosites 90a, 94a in the two separated rows are coupled via transfer gates 98, 106 to storage registers 104, 108 and then to two shift registers 110, 112, and via transfer gates 96 directly to two shift registers 100, 102 in a quadrilinear array. The output of these four shift registers 110,102,110,112 are multiplexed to generate a single output pulse train representative of the information scanned. By separating the offset rows 90, 94 of photosites by a row 92 therebetween, the necessity for accurate alignment of the photosite areas is reduced.Type: GrantFiled: July 20, 1981Date of Patent: December 8, 1987Assignee: Xerox CorporationInventors: Narayan K. Kadekodi, Abd-El-Fattah A. Ibrahim, Roland J. Handy, Jagdish C. Tandon
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Patent number: 4698131Abstract: An image sensor array and method of fabrication which facilitates replacement of a defective one in a series of arrays butted together to form a longer scanning array in which a (110) silicon wafer having a row of photosites has separation lines etched thereon by orientation dependent etching along the (111) planes, with the separation lines for the opposite ends of the array each consisting of first and second partial boundary lines longitudinally offset from one another connected by a third boundary line so that the ends of the array have a has a generally L-shaped offset permitting bi-directional separating and aligned inserting movement when replacing a defective array.In a second embodiment, the arrays are formed on (100) silicon with alternating `nail` head and `mesa` head shapes to facilitate removal and replacement of a defective array.Type: GrantFiled: December 13, 1985Date of Patent: October 6, 1987Assignee: Xerox CorporationInventors: Mehdi N. Araghi, Jagdish C. Tandon
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Patent number: 4695716Abstract: Apparatus and method of fabricating a sensor array from a (110) silicon substrate having a row of photosites to provides a sensor array chip with uniformly smooth and angled ends designed to permit the chip to be lock butted end to end with other like chips to form a full length scanning array in which the substrate is etched for separation along the (111) planes at the desired boundaries of the chip, the etched boundaries delimiting the chip ends running between selected pairs of photosites to provide whole photosites right up to the ends of the chip so as to avoid any cap or interruption between the photosites at the junctions with other chips.In a second embodiment, the chip ends are formed with complementary irregular shapes to enhance locating and butting of the chips with one another, and in a third embodiment, grooves are etched between each of the photosites in the row to assure photosite uniformity and prevent cross talk between photosites.Type: GrantFiled: October 27, 1986Date of Patent: September 22, 1987Assignee: Xerox CorporationInventors: Jagdish C. Tandon, Mehdi N. Araghi
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Patent number: 4690391Abstract: A method and apparatus for fabricating long full width scanning arrays for reading or writing images. For this purpose, smaller scanning arrays are assembled in abutting end-to-end relationship, each of the smaller arrays being provided with a pair of V-shaped locating grooves in the face thereof. An aligning tool having predisposed pin-like projections insertable into the locating grooves on the smaller scanning arrays upon assembly of the smaller arrays with the aligning tool is used to mate a series of the smaller arrays in end-to-end abutting relationship, there being discretely located vacuum ports in the aligning tool to draw the smaller arrays into tight face-to-face contact with the tool. A suitable base is then affixed to the aligned arrays and the aligning tool withdrawn.Type: GrantFiled: January 31, 1983Date of Patent: September 1, 1987Assignee: Xerox CorporationInventors: James C. Stoffel, Jagdish C. Tandon
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Patent number: 4668333Abstract: Apparatus and method of fabricating a sensor array from a (110) silicon substrate having a row of photosites to provide a sensor array chip with uniformly smooth and angled ends designed to permit the chip to be lock butted end to end with other like chips to form a full length scanning array in which the substrate is etched for separation along the (111) planes at the desired boundaries of the chip, the etched boundaries delimiting the chip ends running between selected pairs of photosites to provide whole photosites right up to the ends of the chip so as to avoid any gap or interruption between the photosites at the junctions with other chips.In a second embodiment, the chip ends are formed with complementary irregular shapes to enhance locating and butting of the chips with one another, and in a third embodiment, grooves are etched between each of the photosites in the row to assure photosite uniformity and prevent cross talk between photosites.Type: GrantFiled: December 13, 1985Date of Patent: May 26, 1987Assignee: Xerox CorporationInventors: Jagdish C. Tandon, Mehdi N. Araghi
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Patent number: 4468704Abstract: An adaptive thresholder of the fractional average context type for processing image pixels in which an offset potential, which is used in conjunction with the image potentials of the nearest neighbor pixels to provide an updated threshold potential, is obtained on a pixel by pixel basis as a function of the pixel white peak and black valley potentials. The white peak and black valley potentials are compared with the image potential of each pixel being processed and with predetermined minimum white and maximum black potentials to provide updated white peak and black valley potentials for use in updating the offset potential during processing of each pixel.Type: GrantFiled: October 28, 1982Date of Patent: August 28, 1984Assignee: Xerox CorporationInventors: James C. Stoffel, To R. Hsing, Jagdish C. Tandon
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Patent number: 4438457Abstract: A high density charge coupled device imaging array 58 with a bilinear array 60, 62 of photosites on a single integrated circuit chip is utilized in an image scanning configuration. Offset photosites 60a, 62a in two rows are coupled via transfer gates 64 to storage register 72 and then to two shift registers 74, 76, and via transfer gates 66 directly to two shift registers 68, 70 in a quadrilinear array. The output of these four shift registers 68, 70, 74, 76 are multiplexed to generate a single output pulse train representative of the information scanned.Type: GrantFiled: July 20, 1981Date of Patent: March 20, 1984Assignee: Xerox CorporationInventors: Jagdish C. Tandon, Narayan K. Kadekodi, Abd-El-Fattah A. Ibrahim, Roland J. Handy, James C. Stoffel
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Patent number: 4432017Abstract: A high density charge coupled device imaging array 28 with a bilinear array 30, 32 of photosites on a single integrated circuit chip is utilized in an image scanning configuration. Offset photosites 30a, 32a in two rows are coupled via transfer gates 36 to storage register 38 and then to shift register 44, and via transfer gates 34 to shift register 42. The output of these two shift registers 42, 44 are multiplexed to generate a single output pulse train representative of the information scanned.Type: GrantFiled: July 20, 1981Date of Patent: February 14, 1984Assignee: Xerox CorporationInventors: James C. Stoffel, Jagdish C. Tandon, Ned J. Seachman
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Patent number: 4091379Abstract: An analog to digital wave shaping system comprising, a source of analog signals, adaptive threshold circuitry coupled to said source, said adaptive threshold circuitry having an output selected as a function of the intensity of said analog signal compared to a fixed intensity signal, and, comparator circuitry coupled to said source and to the output of said adaptive threshold circuitry.Type: GrantFiled: May 3, 1976Date of Patent: May 23, 1978Assignee: Litton Business Systems, Inc.Inventors: Paul S. Wu, Jagdish C. Tandon