Patents by Inventor Jeffrey T. Rahn

Jeffrey T. Rahn 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).

  • Publication number: 20100322631
    Abstract: A coherent optical receiver circuit is disclosed in which various components of the optical receiver may be provided or integrated, in one example, on a common substrate. Further integration is achieved by incorporating various optical demultiplexer designs that are relatively compact and conserve space on the surface of the substrate. The optical receiver circuit may be used to demultiplex quadrature phase shift keying (QPSK) optical signals.
    Type: Application
    Filed: June 16, 2010
    Publication date: December 23, 2010
    Inventors: Radhakrishnan L. Nagarajan, Masaki Kato, Jeffrey T. Rahn
  • Patent number: 7271390
    Abstract: An imaging system includes a plurality of gate lines, a plurality of data lines, a common ground line, a plurality of capacitors and an array of pixels that are alternately arranged so that the common ground line is shared by the plurality of capacitors and shared by at least two rows or columns of pixels. A method of forming an array of pixels in an imaging system includes forming a plurality of gate lines, forming a plurality of data lines, forming a common ground line, forming a plurality of capacitors and forming the array of pixels to be alternately arranged so that the common ground line is shared by the plurality of capacitors and shared by at least two rows of pixels.
    Type: Grant
    Filed: December 16, 2004
    Date of Patent: September 18, 2007
    Assignee: Palo Alto Research Center, Incorporated
    Inventor: Jeffrey T Rahn
  • Patent number: 6940142
    Abstract: The signal-to-noise ratio of amorphous silicon (a-Si:H) image sensor arrays is limited by electronic noise, which is largely due to data line capacitance. To reduce data line capacitance, an air-gap (i.e., vacuum or gas-filled space) is produced at crossover points separating the data lines and gate lines. This air-gap crossover structure is formed by depositing a release material on the gate lines, forming the data lines on the release material, and then removing (etching) the release material such that the data lines form an arch extending over the gate lines. A dielectric material is then applied to strengthen the data line, and the sensor pixels are then formed.
    Type: Grant
    Filed: July 2, 2001
    Date of Patent: September 6, 2005
    Assignee: Xerox Corporation
    Inventors: Robert A. Street, Ping Mei, Jeffrey T. Rahn
  • Patent number: 6720594
    Abstract: Improved pixel circuits are disclosed for high fill-factor large area imager systems using continuous (e.g., amorphous silicon) sensor layers. A first approach prevents crosstalk by ensuring that each pixel is not able to go into saturation. A second approach employs a cascode transistor to maintain the bias of the sensor contact at a constant potential regardless of illumination condition. These two approaches may be combined. A resistive film connecting the pixel contacts may be used in conjunction with the second approach to prevent aliasing of signal and noise.
    Type: Grant
    Filed: January 7, 2002
    Date of Patent: April 13, 2004
    Assignee: Xerox Corporation
    Inventors: Jeffrey T. Rahn, Koenraad F. Van Schuylenbergh, Jeng Ping Lu
  • Publication number: 20030127672
    Abstract: Improved pixel circuits are disclosed for high fill-factor large area imager systems using continuous (e.g., amorphous silicon) sensor layers. A first approach prevents crosstalk by ensuring that each pixel is not able to go into saturation. A second approach employs a cascode transistor to maintain the bias of the sensor contact at a constant potential regardless of illumination condition. These two approaches may be combined. A resistive film connecting the pixel contacts may be used in conjunction with the second approach to prevent aliasing of signal and noise.
    Type: Application
    Filed: January 7, 2002
    Publication date: July 10, 2003
    Inventors: Jeffrey T. Rahn, Koenraad F. Van Schuylenbergh, Jeng Ping Lu
  • Patent number: 6579238
    Abstract: A medical ultrasonic imaging system uses an adaptive multi-dimensional back-end mapping stage to eliminate loss of information in the back-end, minimize any back-end quantization noise, reduce or eliminate electronic noise, and map the local average of soft tissue to a target display value throughout the image. The system uses spatial variance to identify regions of the image corresponding substantially to soft tissue and a noise frame acquired with the transmitters turned off to determine the mean system noise level. The system then uses the mean noise level and the identified regions of soft tissue to both locally and adaptively set various back-end mapping stages, including the gain and dynamic range.
    Type: Grant
    Filed: February 23, 2001
    Date of Patent: June 17, 2003
    Assignee: Acuson Corporation
    Inventors: Constantine Simopoulos, Kutay F. Üstüner, Anming He Cai, Jeffrey T. Rahn, John Jackson, Matthew O'Donnell
  • Publication number: 20030001222
    Abstract: The signal-to-noise ratio of amorphous silicon (a-Si:H) image sensor arrays is limited by electronic noise, which is largely due to data line capacitance. To reduce data line capacitance, an air-gap (i.e., vacuum or gas-filled space) is produced at crossover points separating the data lines and gate lines. This air-gap crossover structure is formed by depositing a release material on the gate lines, forming the data lines on the release material, and then removing (etching) the release material such that the data lines form an arch extending over the gate lines. A dielectric material is then applied to strengthen the data line, and the sensor pixels are then formed.
    Type: Application
    Filed: July 2, 2001
    Publication date: January 2, 2003
    Applicant: Xerox Corporation
    Inventors: Robert A. Street, Ping Mei, Jeffrey T. Rahn
  • Patent number: 6408054
    Abstract: Image contrast grids include a body having openings and an x-ray absorbing material in the openings. The openings can be formed by various micromachining techniques and the x-ray absorbing material can be formed in the openings by various coating and deposition techniques. The image contrast grids can have contoured surfaces for improved focusing capabilities. The image contrast grids can remove Compton scattered x-rays in two, non-normal dimensions. The openings can be formed with fine structures that are not visible in most imaging modes.
    Type: Grant
    Filed: November 24, 1999
    Date of Patent: June 18, 2002
    Assignee: Xerox Corporation
    Inventors: Jeffrey T. Rahn, Raj B. Apte