Patents by Inventor John Ladd

John Ladd 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: 7858914
    Abstract: Methods and apparatuses for reducing dark current and hot pixels in CMOS image sensors. A pixel apparatus includes a photosensor capable of generating dark current, a floating diffusion region coupled to the photosensor by way of a charge transfer transistor, a rest transistor connected between the floating diffusion region and an array pixel supply voltage. The array supply voltage varies between first and second voltages when sampling pixel signals from the pixel.
    Type: Grant
    Filed: November 20, 2007
    Date of Patent: December 28, 2010
    Assignee: Aptina Imaging Corporation
    Inventors: Xiangli Li, Richard Mauritzson, Xiaofeng Fan, John Ladd
  • Patent number: 7851798
    Abstract: A method and apparatus for operating an imager pixel that includes the act of applying a relatively small first polarity voltage and a plurality of pulses of a second polarity voltage on the gate of a transfer transistor during a charge integration period.
    Type: Grant
    Filed: May 4, 2005
    Date of Patent: December 14, 2010
    Assignee: Micron Technology, Inc.
    Inventor: John Ladd
  • Publication number: 20100309351
    Abstract: Image sensors and color filter arrays for in-pixel charge summing and interlaced readout modes may be provided. An image sensor that supports charge summing and interlaced readout modes may include an array of pixels with pairs of adjacent green, red, and blue light-sensitive pixels. An image sensor may implement an in-pixel charge summing readout mode in which charges from pairs of pixels are summed onto a common node and then read out from the common node. An image sensor may implement an interlaced readout mode in which image data is read out from alternating rows of the image sensor. An image sensor may use a shared readout scheme in which a group of four pixels is formed from two pairs of commonly-colored pixels. The four pixels may share circuitry such as a reset transistor, a buffer transistor, and a row select transistor and may connect to a single readout line.
    Type: Application
    Filed: June 8, 2009
    Publication date: December 9, 2010
    Inventors: Scott Smith, John Ladd
  • Patent number: 7808063
    Abstract: Imaging devices having reduced fixed pattern noise are disclosed. The fixed pattern noise in the imaging devices is reduced by measuring and adjusting the spectral characteristics of the imager device on a pixel by pixel basis. The fixed pattern noise of the pixel cells are changed by modifying the absorption, reflectance, refractive index, shape, and/or micro structure of the material.
    Type: Grant
    Filed: May 26, 2005
    Date of Patent: October 5, 2010
    Assignee: Micron Technology, Inc.
    Inventors: Ulrich C. Boettiger, John Ladd
  • Patent number: 7704782
    Abstract: Imager devices having an array of photosensors, each photosensor having at least two doped regions. The two doped regions are each independently tailored to a particular wavelength.
    Type: Grant
    Filed: August 30, 2005
    Date of Patent: April 27, 2010
    Assignee: Aptina Imaging Corporation
    Inventors: John Ladd, Inna Patrick, Gennadiy A. Agranov, Jeff A. McKee
  • Patent number: 7696597
    Abstract: A pixel with a photosensor and a transfer transistor having a split transfer gate. A first section of the transfer gate is connectable to a first voltage source while a second section of the transfer gate is connectable to a second voltage source. Thus, during a charge integration period of a photosensor, the two sections of the transfer gate may be oppositely biased to decrease dark current while controlling blooming of electrons within and out of the pixel cell. During charge transfer the two gate sections may be commonly connected to a positive voltage sufficient to transfer charge from the photosensor to a floating diffusion region.
    Type: Grant
    Filed: June 24, 2009
    Date of Patent: April 13, 2010
    Assignee: Aptina Imaging Corporation
    Inventor: John Ladd
  • Patent number: 7663167
    Abstract: A pixel with a photosensor and a transfer transistor having a split transfer gate. A first section of the transfer gate is connectable to a first voltage source while a second section of the transfer gate is connectable to a second voltage source. Thus, during a charge integration period of a photosensor, the two sections of the transfer gate may be oppositely biased to decrease dark current while controlling blooming of electrons within and out of the pixel cell. During charge transfer the two gate sections may be commonly connected to a positive voltage sufficient to transfer charge from the photosensor to a floating diffusion region.
    Type: Grant
    Filed: December 23, 2004
    Date of Patent: February 16, 2010
    Assignee: Aptina Imaging Corp.
    Inventor: John Ladd
  • Patent number: 7642107
    Abstract: A pixel with a photosensor and a transfer transistor having a split transfer gate. A first section of the transfer gate is connectable to a first voltage source while a second section of the transfer gate is connectable to a second voltage source. Thus, during a charge integration period of a photosensor, the two sections of the transfer gate may be oppositely biased to decrease dark current while controlling blooming of electrons within and out of the pixel cell. During charge transfer the two gate sections may be commonly connected to a positive voltage sufficient to transfer charge from the photosensor to a floating diffusion region.
    Type: Grant
    Filed: December 21, 2006
    Date of Patent: January 5, 2010
    Assignee: Aptina Imaging Corporation
    Inventor: John Ladd
  • Publication number: 20090322913
    Abstract: A pixel with a photosensor and a transfer transistor having a split transfer gate. A first section of the transfer gate is connectable to a first voltage source while a second section of the transfer gate is connectable to a second voltage source. Thus, during a charge integration period of a photosensor, the two sections of the transfer gate may be oppositely biased to decrease dark current while controlling blooming of electrons within and out of the pixel cell. During charge transfer the two gate sections may be commonly connected to a positive voltage sufficient to transfer charge from the photosensor to a floating diffusion region.
    Type: Application
    Filed: June 24, 2009
    Publication date: December 31, 2009
    Inventor: John Ladd
  • Patent number: 7619671
    Abstract: A method and apparatus are provided for operation of an image sensor during signal readout. During a reset operation the gate of a reset transistor coupled to the storage node receives a voltage greater than a threshold voltage to produce a reset of the storage node. During a period where photogenerated charges stored at the storage node are read out the gate of the reset transistor receives a voltage VRST—LOW greater than ground, but less than a maximum voltage which can be stored at the storage node.
    Type: Grant
    Filed: July 18, 2006
    Date of Patent: November 17, 2009
    Assignee: Aptina Imaging Corporation
    Inventors: Xiangli Li, Chen Xu, Peter Parker Altice, John Ladd
  • Publication number: 20090237541
    Abstract: An imaging device and method for operating the device. The imaging device comprises a pixel array having a plurality of pixels arranged in rows and columns. At least one pixel of the array comprises a photosensor and a first reset circuit responsive to a first reset control signal for resetting the photosensor. A first terminal of the first reset circuit is coupled to the photosensor and a second terminal of the first reset circuit is configured to receive a first resetting voltage from a control line.
    Type: Application
    Filed: March 20, 2008
    Publication date: September 24, 2009
    Inventors: Richard S. Johnson, John Ladd
  • Patent number: 7538304
    Abstract: A method of operating an imager to have increased capacitance on a pixel output or column output line during most reset signal and pixel signal sampling operations from the line. The increased capacitance is achieved by switching in multiple sample and hold capacitors during the sampling operations.
    Type: Grant
    Filed: March 30, 2006
    Date of Patent: May 26, 2009
    Assignee: Aptina Imaging Corporation
    Inventor: John Ladd
  • Publication number: 20090127437
    Abstract: Methods and apparatuses for reducing dark current and hot pixels in CMOS image sensors. A pixel apparatus includes a photosensor capable of generating dark current, a floating diffusion region coupled to the photosensor by way of a charge transfer transistor, a rest transistor connected between the floating diffusion region and an array pixel supply voltage. The array supply voltage varies between first and second voltages when sampling pixel signals from the pixel.
    Type: Application
    Filed: November 20, 2007
    Publication date: May 21, 2009
    Applicant: MICRON TECHNOLOGY, INC.
    Inventors: Xiangli Li, Richard Mauritzson, Xiaofeng Fan, John Ladd
  • Publication number: 20090101796
    Abstract: Methods, systems and apparatuses proving a high dynamic range imager. Multiple photosensor integration periods are used to capture pixel signal information. A transistor gate is used to remove electrons from the photosensor between the two successive integration periods providing a non-linear pixel response characteristic having a knee point. Each pixel is calibrated for the knee point which is used during adjustment of the pixel output signal. Each pixel may also be calibrated with an arbitrary signal response curve for multiple light intensities.
    Type: Application
    Filed: October 23, 2007
    Publication date: April 23, 2009
    Inventors: John Ladd, Gennadiy A. Agranov, Dmitri Jerdev
  • Publication number: 20090103827
    Abstract: Methods, systems and apparatuses for using regular and/or dark pixels of a pixel array in either a fixed or dynamic fashion to compensate for fixed pattern noise.
    Type: Application
    Filed: October 19, 2007
    Publication date: April 23, 2009
    Inventors: John Ladd, Gennadiy Agranov, Johannes Solhusvik, Trygve Willassen
  • Publication number: 20080291310
    Abstract: A pixel having no dedicated reset control line. By using the voltage on the column line to control the gate of the reset transistor, there is no need to provide a dedicate reset control line.
    Type: Application
    Filed: May 21, 2007
    Publication date: November 27, 2008
    Inventors: John Ladd, Gennadiy A. Agranov
  • Publication number: 20080018762
    Abstract: A method and apparatus are provided for operation of an image sensor during signal readout. During a reset operation the gate of a reset transistor coupled to the storage node receives a voltage greater than a threshold voltage to produce a reset of the storage node. During a period where photogenerated charges stored at the storage node are read out the gate of the reset transistor receives a voltage VRST—LOW greater than ground, but less than a maximum voltage which can be stored at the storage node.
    Type: Application
    Filed: July 18, 2006
    Publication date: January 24, 2008
    Inventors: Xiangli Li, Chen Xu, Peter Parker Altice, John Ladd
  • Publication number: 20070235631
    Abstract: A method of operating an imager to have increased capacitance on a pixel output or column output line during most reset signal and pixel signal sampling operations from the line. The increased capacitance is achieved by switching in multiple sample and hold capacitors during the sampling operations.
    Type: Application
    Filed: March 30, 2006
    Publication date: October 11, 2007
    Inventor: John Ladd
  • Publication number: 20070102781
    Abstract: A pixel with a photosensor and a transfer transistor having a split transfer gate. A first section of the transfer gate is connectable to a first voltage source while a second section of the transfer gate is connectable to a second voltage source. Thus, during a charge integration period of a photosensor, the two sections of the transfer gate may be oppositely biased to decrease dark current while controlling blooming of electrons within and out of the pixel cell. During charge transfer the two gate sections may be commonly connected to a positive voltage sufficient to transfer charge from the photosensor to a floating diffusion region.
    Type: Application
    Filed: December 21, 2006
    Publication date: May 10, 2007
    Inventor: John Ladd
  • Publication number: 20070045680
    Abstract: Imager devices having an array of photosensors, each photosensor having at least two doped regions. The two doped regions are each independently tailored to a particular wavelength.
    Type: Application
    Filed: August 30, 2005
    Publication date: March 1, 2007
    Inventors: John Ladd, Inna Patrick, Gennadiy Agranov, Jeff McKee