Patents by Inventor Kalluri R. Sarma

Kalluri R. Sarma 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: 20080297452
    Abstract: Apparatus, systems, and methods are provided for dimming pixels on an active matrix light-emitting diode display. One apparatus includes an LED couplable between a voltage source and ground. First and second pulse-width modulation (PWM) drivers are also coupled to the LED. A system includes a plurality of LEDs forming a plurality of rows coupled between a voltage source and ground. A plurality of PWM drivers, each coupled to each of the LEDs in one of the plurality of rows, and a global PWM driver coupled to each of the plurality of LEDs in each of the plurality of rows are also included. One method includes providing current to each LED of a row of LEDs for a first portion of a cycle via a PWM driver, and providing current to each LED in the row for a second portion of the cycle via a different PWM driver.
    Type: Application
    Filed: May 30, 2007
    Publication date: December 4, 2008
    Applicant: HONEYWELL INTERNATIONAL, INC.
    Inventors: Jerry A. Roush, Kalluri R. Sarma, John F. L. Schmidt
  • Publication number: 20080284693
    Abstract: An improved AM OLED pixel circuit and method of wide dynamic range dimming for AM OLED displays are disclosed that maintain color balance throughout the dimming range, and also maintain the uniformity of the luminance and chromaticity of the display at low gray-levels as the display is dimmed to lower luminance values. As such, AM OLED displays can meet the stringent color/dimming specifications required for existing and future avionics, cockpit, and hand-held military device display applications. Essentially, the OLED pixel circuit and method of dimming that are disclosed use Pulse Width Modulation (PWM) of the OLED pixel current to achieve the desired display luminance. Two example circuits are disclosed that externally PW modulate the common cathode voltage or common power supply voltage to modulate the OLED current in order to achieve the desired display luminance.
    Type: Application
    Filed: April 22, 2008
    Publication date: November 20, 2008
    Applicant: HONEYWELL INTERNATIONAL INC.
    Inventors: Kalluri R. Sarma, Jerry A. Roush, John Schmidt
  • Patent number: 7316942
    Abstract: An active matrix display backplane is formed by annealing a flexible dielectric substrate, and then forming one or more thin-film-transistors (TFTs), one or more pixel electrodes, and an interconnect on a surface of the annealed substrate. The interconnect includes individual, spaced apart electrodes that are electrically coupled to one another. One of the interconnect electrodes is electrically coupled to a TFT, and the other interconnect electrode is electrically coupled to the pixel electrode, to thereby electrically interconnect the TFT and the pixel electrode.
    Type: Grant
    Filed: February 14, 2005
    Date of Patent: January 8, 2008
    Assignee: Honeywell International, Inc.
    Inventors: Kalluri R. Sarma, Charles Chanley
  • Publication number: 20060046335
    Abstract: The present invention provides amorphous silicon thin-film transistors and methods of making such transistors for use with active matrix displays. In particular, one aspect of the present invention provides transistors having a structure based on a channel passivated structure wherein the amorphous silicon layer thickness and the channel length can be optimized. In another aspect of the present invention thin-film transistor structures that include a contact enhancement layer that can provide a low threshold voltage are provided.
    Type: Application
    Filed: September 1, 2004
    Publication date: March 2, 2006
    Inventors: Kalluri R. Sarma, Charles S. Chanley
  • Patent number: 6680766
    Abstract: A display according to various aspects of the present invention comprises an LCD having a first substrate, a second substrate proximate the first substrate, a liquid crystal material located between the first and second substrates, an element for compensating for horizontal view angle limitations of the display. The LCD may further include a nonmechanical element for vertically shifting the viewing angle associated with the high-contrast viewing envelope of the LCD device.
    Type: Grant
    Filed: December 31, 1998
    Date of Patent: January 20, 2004
    Assignee: Honeywell Inc.
    Inventors: Brent D. Larson, Elias S. Haim, Kalluri R. Sarma, Syed H. Jamal
  • Patent number: 6498073
    Abstract: The present invention is a back illuminated image array device and a method of constructing such a device. The device is generally comprised of an array circuitry layer, a front layer, and a quartz layer. The array circuitry layer is defined on one surface of the front layer. The quartz layer is mounted on the other surface of the front layer. The method of fabricating the device is generally comprised of the following steps. The method provides a wafer having a thick silicon layer, an oxide layer on the thick silicon layer, and a front silicon layer on the oxide layer. The front layer has a first surface and a second surface with the second surface proximal to the oxide layer. Array circuitry is formed on the first surface of the front layer. A temporary layer is applied to the surface of the array circuitry. The thick silicon layer and the oxide layers are removed from the wafer, thereby, exposing the second surface of the front layer. A quartz layer is applied to the second surface.
    Type: Grant
    Filed: January 2, 2001
    Date of Patent: December 24, 2002
    Assignee: Honeywell International Inc.
    Inventors: Kalluri R. Sarma, Charles S. Chanley
  • Publication number: 20020084474
    Abstract: The present invention is a back illuminated image array device and a method of constructing such a device. The device is generally comprised of an array circuitry layer, a front layer, and a quartz layer. The array circuitry layer is defined on one surface of the front layer. The quartz layer is mounted on the other surface of the front layer. The method of fabricating the device is generally comprised of the following steps. The method provides a wafer having a thick silicon layer, an oxide layer on the thick silicon layer, and a front silicon layer on the oxide layer. The front layer has a first surface and a second surface with the second surface proximal to the oxide layer. Array circuitry is formed on the first surface of the front layer. A temporary layer is applied to the surface of the array circuitry. The thick silicon layer and the oxide layers are removed from the wafer, thereby, exposing the second surface of the front layer. A quartz layer is applied to the second surface.
    Type: Application
    Filed: January 2, 2001
    Publication date: July 4, 2002
    Inventors: Kalluri R. Sarma, Charles S. Chanley
  • Patent number: 5831693
    Abstract: The active matrix liquid crystal display panel comprises a matrix of predetermined color filters, arranged in a predetermined configuration within a viewing area, deposited on a first substrate, and a first plate of an activating element is deposited over the matrix of predetermined color filters. A plurality of second plates of the activating element is deposited on a second substrate opposite each color filter. When a predetermined second plate is activated, light is permitted to pass through the corresponding filter, the light exiting the first substrate having the color of the corresponding filter. A plurality of thin film transistors is deposited on the second substrate and forms the control elements, each control element corresponding to a corresponding second plate of the activating element, the control element selecting predetermined second plate in response to control signals. The display panel includes a liquid crystal material filled in a space between the first and second substrate.
    Type: Grant
    Filed: February 22, 1996
    Date of Patent: November 3, 1998
    Assignee: Honeywell
    Inventors: Richard Isaiah McCartney, Jr., Kalluri R. Sarma
  • Patent number: 5717474
    Abstract: A multi-domain halftone gray scale active matrix liquid crystal display utilizing a mono-gap configuration for achieving a very wide viewing angle at a low-cost. The substrate of the display has areas having a rub or an alignment of different directions from the direction of the rub or alignment in other adjacent areas. Each pixel of the gray scale matrix has a plurality of subpixels such that each subpixel turns on at a different voltage than that of the other subpixels. The areas involving different rubs or alignments on the substrates may be areas of pixels or subpixels. At least one compensating retardation layer is formed on the display. The technique of enabling the combining of multiple domains and compensation with halftone grayscale pixels results in a display having significantly wider viewing angles than either a multi-domain display or a halftone grayscale display, whether compensated for or not.
    Type: Grant
    Filed: September 30, 1994
    Date of Patent: February 10, 1998
    Assignee: Honeywell Inc.
    Inventor: Kalluri R. Sarma
  • Patent number: 5659192
    Abstract: A back-etch silicon-on-insulator SOI process that has a silicon handle wafer with an oxide layer bonded at room temperature to a silicon device wafer with an etch stop and silicon device layer. The surfaces that are bonded at room temperature are first conditioned to be hydrophilic. After bonding, the edges of the layers are sealed. The silicon device wafer, the etch-stop layer and the device layer are boron doped. Most of the silicon device wafer is ground away. Then, the remaining portion of the silicon device wafer and the etch stop layer are chemically etched away, thereby leaving a uniform layer of silicon device layer on the oxide layer of the silicon handle wafer.
    Type: Grant
    Filed: January 27, 1997
    Date of Patent: August 19, 1997
    Assignee: Honeywell Inc.
    Inventors: Kalluri R. Sarma, Michael S. Liu
  • Patent number: 5646702
    Abstract: A liquid crystal display having pixels illuminated by field emitter arrays. The field emitter arrays may be utilized to illuminate each pixel individually or to be a backlight lamp to illuminate the whole display, whether monochrome or color. A field emitter array back-lighted liquid crystal displays, whether active matrix or passive, provide greater compactness, higher luminous efficiency, more brightness, and longer lifetime than a fluorescent lamp. Field-emitter arrays may also provide light in various colors for the liquid crystal display thereby eliminating the need for color filters which result in duller colors than that of field emitter arrays. Each color filter absorbs two-thirds of the light that it receives. A color filter liquid crystal color display exhibits colors that have diminished chromaticity and purity in comparison to those of a field emitter array liquid crystal display.
    Type: Grant
    Filed: October 31, 1994
    Date of Patent: July 8, 1997
    Assignee: Honeywell Inc.
    Inventors: Akintunde Ibitayo (Tayo) Akinwande, Kalluri R. Sarma
  • Patent number: 5536950
    Abstract: A transistor panel used for active matrix display devices includes islands of single crystal silicon formed on a transparent quartz substrate and arranged in rows and columns, with an NMOS transistor formed in each island. Each transistor includes source, drain and channel regions and an isolated pixel reference voltage region. A silicon body tie connects the channel region to the pixel reference voltage region and acts as a current sink for unwanted carriers thereby greatly increasing the snapback voltage. A metallization extends to each transistor and is in contact with each reference voltage region to form a body tie buss. The portion of the body tie that overlaps the pixel electrode may be sized to provide a storage capacitor for improved display performance. The unique body tie design obviates the need for a separate light shield layer, provides a dramatically increased aperture ratio and is compatible with normal high temperature silicon processes.
    Type: Grant
    Filed: October 28, 1994
    Date of Patent: July 16, 1996
    Assignee: Honeywell Inc.
    Inventors: Michael S. Liu, Ka-Lun Lo, Kalluri R. Sarma
  • Patent number: 5471330
    Abstract: A liquid crystal display wherein each pixel has a thin film transistor with a silicon pixel electrode. A doping and recrystallization of the silicon is effected to increase the electrical conductivity and light transmittance of the silicon adequately for the pixel electrode.
    Type: Grant
    Filed: July 29, 1993
    Date of Patent: November 28, 1995
    Assignee: Honeywell Inc.
    Inventor: Kalluri R. Sarma
  • Patent number: 5308779
    Abstract: High mobility thin film transistors for fabricating integrated drivers for active matrix displays and a special method of fabrication for obtaining the thin film transistors having mobility sufficiently high enough as drivers operable in the several megahertz frequency range needed for driving high resolution active matrix displays.
    Type: Grant
    Filed: August 13, 1993
    Date of Patent: May 3, 1994
    Assignee: Honeywell Inc.
    Inventor: Kalluri R. Sarma
  • Patent number: 5281840
    Abstract: High mobility thin film transistors for fabricating integrated drivers for active matrix displays and a special method of fabrication for obtaining the thin film transistors having mobility sufficiently high enough as drivers operable in the several megahertz frequency range needed for driving high resolution active matrix displays.
    Type: Grant
    Filed: August 17, 1992
    Date of Patent: January 25, 1994
    Assignee: Honeywell Inc.
    Inventor: Kalluri R. Sarma
  • Patent number: 5258323
    Abstract: A method for fabricating single crystal islands on a high temperature substrate, thereby allowing for the use of high temperature processes to further make devices incorporating the islands such as, for example, high mobility thin film transistor integrated drivers for active matrix displays.
    Type: Grant
    Filed: December 29, 1992
    Date of Patent: November 2, 1993
    Assignee: Honeywell Inc.
    Inventors: Kalluri R. Sarma, Charles S. Chanley
  • Patent number: 5204659
    Abstract: A liquid crystal display is described that includes gray scale capability. Each pixel of the display is subdivided into a plurality of subpixels. Each subpixel has coupled thereto a thin film transistor, the thin film transistor coupled to the effective subpixel capacitor. The liquid crystal material is contained between the effective capacitor plates. The voltage applied to the effective capacitor resulting from current flowing through the thin film transistor controls the optical activity of the subpixel. By controlling parameters associated with the thin transistor and by controlling the voltage applied to the pixel (and the subpixel thin film transistors), the optical properties of the subpixel can be controlled as a result of the charge applied across the effective capacitor to provide an angular independent gray scale for the pixel.
    Type: Grant
    Filed: August 3, 1990
    Date of Patent: April 20, 1993
    Assignee: Honeywell Inc.
    Inventor: Kalluri R. Sarma
  • Patent number: 5191452
    Abstract: A structure and method of fabricating a active matrix display with halftone grayscale and wide viewing angle, having an active matrix array and a control capacitor array fabricated on separate substrates.
    Type: Grant
    Filed: September 20, 1989
    Date of Patent: March 2, 1993
    Assignee: Honeywell Inc.
    Inventor: Kalluri R. Sarma
  • Patent number: 5168074
    Abstract: A structure and method of fabricating a active matrix display with halftone grayscale and wide viewing angle, having an active matrix array and a control capacitor array fabricated on separate substrates.
    Type: Grant
    Filed: May 7, 1991
    Date of Patent: December 1, 1992
    Assignee: Honeywell Inc.
    Inventor: Kalluri R. Sarma
  • Patent number: 5126865
    Abstract: A half-tone pixel having subpixels and control capacitor constituting a 100 percent optically active pixel. The subpixel design results in no reductions in the maximum pixel aperture ratio, brightness or contrast, as a pixel with no subpixels would have. Various subpixel layouts including differing numbers of subpixels and subpixel-turn-on sequences may be implemented and still result in the entire pixel being optically active.
    Type: Grant
    Filed: December 31, 1990
    Date of Patent: June 30, 1992
    Assignee: Honeywell Inc.
    Inventor: Kalluri R. Sarma