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).

  • Patent number: 5031032
    Abstract: 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: Grant
    Filed: March 30, 1990
    Date of Patent: July 9, 1991
    Assignee: Xerox Corporation
    Inventors: Alain E. Perregaux, Jagdish C. Tandon, Josef E. Jedlicka
  • Patent number: 5029020
    Abstract: 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: Grant
    Filed: November 17, 1989
    Date of Patent: July 2, 1991
    Assignee: Xerox Corporation
    Inventors: Paul D. Norder, Jagdish C. Tandon, Ying-wei Lin, Anthony F. Calarco
  • Patent number: 4860075
    Abstract: 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: Grant
    Filed: January 1, 1989
    Date of Patent: August 22, 1989
    Assignee: Xerox Corporation
    Inventors: Mehdi N. Araghi, Jagdish C. Tandon
  • Patent number: 4830985
    Abstract: 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: Grant
    Filed: April 16, 1987
    Date of Patent: May 16, 1989
    Assignee: Xerox Corporation
    Inventors: Mehdi N. Araghi, Jagdish C. Tandon
  • Patent number: 4761683
    Abstract: 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: Grant
    Filed: December 18, 1986
    Date of Patent: August 2, 1988
    Assignee: Xerox Corporation
    Inventors: Ronald G. Matteson, Jagdish C. Tandon
  • Patent number: 4737854
    Abstract: 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: Grant
    Filed: July 18, 1986
    Date of Patent: April 12, 1988
    Assignee: Xerox Corporation
    Inventors: Jagdish C. Tandon, Pierre A. Lavallee
  • Patent number: 4735671
    Abstract: 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: Grant
    Filed: March 26, 1987
    Date of Patent: April 5, 1988
    Assignee: Xerox Corporation
    Inventors: James C. Stoffel, Jagdish C. Tandon
  • Patent number: 4712018
    Abstract: 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: Grant
    Filed: March 26, 1987
    Date of Patent: December 8, 1987
    Assignee: Xerox Corporation
    Inventors: James C. Stoffel, Jagdish C. Tandon
  • Patent number: 4712137
    Abstract: 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: Grant
    Filed: July 20, 1981
    Date of Patent: December 8, 1987
    Assignee: Xerox Corporation
    Inventors: Narayan K. Kadekodi, Abd-El-Fattah A. Ibrahim, Roland J. Handy, Jagdish C. Tandon
  • Patent number: 4698131
    Abstract: 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: Grant
    Filed: December 13, 1985
    Date of Patent: October 6, 1987
    Assignee: Xerox Corporation
    Inventors: Mehdi N. Araghi, Jagdish C. Tandon
  • Patent number: 4695716
    Abstract: 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: Grant
    Filed: October 27, 1986
    Date of Patent: September 22, 1987
    Assignee: Xerox Corporation
    Inventors: Jagdish C. Tandon, Mehdi N. Araghi
  • Patent number: 4690391
    Abstract: 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: Grant
    Filed: January 31, 1983
    Date of Patent: September 1, 1987
    Assignee: Xerox Corporation
    Inventors: James C. Stoffel, Jagdish C. Tandon
  • Patent number: 4668333
    Abstract: 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: Grant
    Filed: December 13, 1985
    Date of Patent: May 26, 1987
    Assignee: Xerox Corporation
    Inventors: Jagdish C. Tandon, Mehdi N. Araghi
  • Patent number: 4468704
    Abstract: 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: Grant
    Filed: October 28, 1982
    Date of Patent: August 28, 1984
    Assignee: Xerox Corporation
    Inventors: James C. Stoffel, To R. Hsing, Jagdish C. Tandon
  • Patent number: 4438457
    Abstract: 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: Grant
    Filed: July 20, 1981
    Date of Patent: March 20, 1984
    Assignee: Xerox Corporation
    Inventors: Jagdish C. Tandon, Narayan K. Kadekodi, Abd-El-Fattah A. Ibrahim, Roland J. Handy, James C. Stoffel
  • Patent number: 4432017
    Abstract: 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: Grant
    Filed: July 20, 1981
    Date of Patent: February 14, 1984
    Assignee: Xerox Corporation
    Inventors: James C. Stoffel, Jagdish C. Tandon, Ned J. Seachman
  • Patent number: 4091379
    Abstract: 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: Grant
    Filed: May 3, 1976
    Date of Patent: May 23, 1978
    Assignee: Litton Business Systems, Inc.
    Inventors: Paul S. Wu, Jagdish C. Tandon