Patents by Inventor John W. Hamer

John W. Hamer 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: 20100259166
    Abstract: A flexible emissive device, includes a flexible rough substrate having a rough substrate surface and defining a display area; an organic low-temperature adhesion layer formed on the rough substrate surface, at least a portion of the organic low-temperature adhesion layer having a thickness greater than or equal to five microns; a plurality of chiplets distributed in the display area and adhering to the organic low-temperature adhesion layer, each chiplet having one or more connection pads; a plurality of patterned bottom electrodes formed over the organic low-temperature adhesion layer in the display area, each bottom electrode being electrically connected to only one connection pad of a corresponding chiplet; one or more layers of light-emitting material formed over the bottom electrode; and a top electrode formed over the one or more layers of light-emitting material; and a flexible encapsulating layer located over the top electrode and adhered to the rough substrate surface.
    Type: Application
    Filed: April 9, 2009
    Publication date: October 14, 2010
    Inventors: Ronald S. Cok, John W. Hamer
  • Publication number: 20100225630
    Abstract: An electroluminescent (EL) subpixel, such as an organic light-emitting diode (OLED) subpixel, is compensated for aging effects such as threshold voltage Vth shift, EL voltage Voled shift, and OLED efficiency loss. The drive current of the subpixel is measured at one or more measurement reference gate voltages to form a status signal representing the characteristics of the drive transistor and EL emitter of the subpixel. Current measurements are taken in the linear region of drive transistor operation to improve signal-to-noise ratio in systems such as modern LTPS PMOS OLED displays, which have relatively small Voled shift over their lifetimes and thus relatively small current change due to channel-length modulation. Various sources of noise are also suppressed to further increase signal-to-noise ratio.
    Type: Application
    Filed: March 3, 2009
    Publication date: September 9, 2010
    Inventors: Charles I. Levey, John W. Hamer
  • Publication number: 20100225634
    Abstract: Subpixels on an electroluminescent (EL) display panel, such as an organic light-emitting diode (OLED) panel, are compensated for initial nonuniformity (“mura”) and for aging effects such as threshold voltage Vth shift, EL voltage Voled shift, and OLED efficiency loss. The drive current of each subpixel is measured at one or more measurement reference gate voltages to form status signals representing the characteristics of the drive transistor and EL emitter of those subpixels. Current measurements are taken in the linear region of drive transistor operation to improve signal-to-noise ratio in systems such as modern LTPS PMOS OLED displays, which have relatively small Voled shift over their lifetimes and thus relatively small current change due to channel-length modulation. Various sources of noise are also suppressed to further increase signal-to-noise ratio.
    Type: Application
    Filed: March 4, 2009
    Publication date: September 9, 2010
    Inventors: Charles I. Levey, John W. Hamer
  • Publication number: 20100213819
    Abstract: A flexible emissive display device having an adhesion layer thinner than the device substrate; a plurality of chiplets adhered to the adhesion layer wherein at least a portion of the adhesion layer extends above a portion of the chiplets; an OLED formed over the adhesion layer and wherein the OLED is thinner than the adhesion layer; a cover thicker than the adhesion layer located over the OLED and adhered to the device substrate; and wherein the chiplets and OLED are at or near the neutral stress plane of the device and the bending radius of the device is less than 2 cm.
    Type: Application
    Filed: February 25, 2009
    Publication date: August 26, 2010
    Inventors: Ronald S. Cok, John W. Hamer
  • Publication number: 20100207851
    Abstract: A display device, including a substrate; a first layer having an array of row electrodes formed in rows across the substrate in a first direction and a second layer having an array of column electrodes formed in columns across the substrate in a second direction different from the first direction wherein the row and column electrodes overlap to form pixel locations; one or more layers of light-emitting material formed between the row and column electrodes to form a two-dimensional array of pixels, the pixels being located in the pixel locations; and a plurality of row driver chiplets and a separate plurality of column driver chiplets distributed relative to the two-dimensional array of pixels, each row driver chiplet exclusively connected to and controlling an independent set of row electrodes and each column driver chiplet exclusively connected to and controlling an independent set of column electrodes.
    Type: Application
    Filed: February 17, 2009
    Publication date: August 19, 2010
    Inventors: Ronald S. Cok, John W. Hamer
  • Publication number: 20100207849
    Abstract: A display device, including a substrate; a first layer having an array of row electrodes formed in rows across the substrate in a first direction and a second layer having an array of column electrodes formed in columns across the substrate in a second direction different from the first direction wherein the row and column electrodes overlap to form pixel locations; one or more layers of light-emitting material formed between the row and column electrodes to form a two-dimensional array of pixels, the pixels being located in the pixel locations; and a plurality of chiplets located over the substrate, the number of chiplets being less than the number of pixels, each chiplet exclusively controlling a subset of row electrodes and a subset of column electrodes, whereby the pixels are controlled to display an image.
    Type: Application
    Filed: February 18, 2009
    Publication date: August 19, 2010
    Inventors: Ronald S. Cok, John W. Hamer
  • Publication number: 20100201275
    Abstract: A method for controlling an OLED display includes providing an OLED device and a controller, measuring and communicating the amount of ambient and emitted OLED light incident upon an array of photosensors distributed over the display area for measuring the incident light, operating the OLED pixels with at least one calibration image and forming an OLED compensation map in response to a first measured incident light, receiving a second incident light measurement and forming an ambient illumination map, receiving and compensating an image and driving the OLED pixels with the compensated image, receiving a third incident light measurement and forming large-area average values and small-area average values, and comparing the large-area average values and the small-area average values to a predetermined criterion, and determining the location of one or more light occlusions or reflections.
    Type: Application
    Filed: February 6, 2009
    Publication date: August 12, 2010
    Inventors: RONALD S. COK, John W. Hamer
  • Publication number: 20100156766
    Abstract: An electroluminescent (EL) subpixel driven by a digital-drive scheme has a readout transistor driven by a current source when the drive transistor is non-conducting. This produces an emitter-voltage signal from which an aging signal representing the efficiency of the EL emitter can be computed. The aging signal is used to determine the loss in current of the subpixel when active, and an input signal is adjusted to provide increased on-time to compensate for voltage rise and efficiency loss of the EL emitter. Variations due to temperature can also be compensated for.
    Type: Application
    Filed: December 18, 2008
    Publication date: June 24, 2010
    Inventors: Charles I. Levey, Fellpe A. Leon, John W. Hamer, Gary Parett, Christopher J. White
  • Publication number: 20100123649
    Abstract: Compensation is performed for initial nonuniformity or aging of drive transistors and electroluminescent (EL) emitters in 3T1C EL subpixels of an EL display, such as an organic light-emitting diode (OLED) display. A readout transistor connected to the EL emitter is used to readout the voltage of the emitter and compensation for ?Vth, ?VEL, and OLED efficiency loss is performed using a model. Measurements are taken during a frame by driving a target subpixel at a higher luminance for a shorter time, then using the remaining time in the frame to measure. Measurements can be taken with an A/D converter or with a ramp generator and comparator. Compensation is performed for each subpixel individually.
    Type: Application
    Filed: November 17, 2008
    Publication date: May 20, 2010
    Inventors: John W. Hamer, Gary Parrett, Charles I. Levey
  • Publication number: 20100123384
    Abstract: An area-emissive light-emitting diode (LED) device comprises a substrate having an internal substrate surface, an external substrate surface opposite the internal substrate surface, and a substrate edge; an array of area-emissive LED pixels formed on the internal substrate surface with an edge gap between the substrate edge and the LED pixel on the internal substrate surface nearest the substrate edge; and a light-extraction structure formed in the edge gap and at least partially exterior to the LED pixels.
    Type: Application
    Filed: November 17, 2008
    Publication date: May 20, 2010
    Inventors: Michael E. Miller, John W. Hamer, Ronald S. Cok
  • Publication number: 20100123694
    Abstract: A display device having a hybrid drive including a substrate, a two-dimensional pixel array formed on the substrate, the pixels associated into a plurality of pixel groups. A separate set of group row electrodes and group column electrodes are connected to pixels in pixel groups, so that a single group row electrode together with a single group column electrode drives a single pixel. Two or more chiplets are located over the substrate within the pixel array, each chiplet associated with a pixel group and having connections to each of the associated group row electrodes and associated group column electrodes and having storage elements, the storage element storing a value representing a desired luminance for a pixel and the chiplet using such value to control the desired luminance of each pixel in its associated pixel group.
    Type: Application
    Filed: November 17, 2008
    Publication date: May 20, 2010
    Inventors: Ronald S. Cok, John W. Hamer, Janos Veres
  • Publication number: 20100123141
    Abstract: An emissive device includes a substrate having a substrate surface; a chiplet adhered to the substrate surface, the chiplet having one or more connection pads; a bottom electrode formed on the substrate surface, one or more organic or inorganic light-emitting layers formed over the bottom electrode, and a top electrode formed over the one or more organic or inorganic light-emitting layers; an electrical conductor including a transition layer formed over only a portion of the chiplet and only a portion of the substrate surface, the transition layer exposing at least one connection pad, the electrical conductor formed in electrical contact with the exposed connection pad and the bottom electrode; and an LED spaced from the chiplet and including a layer of light-emissive material formed over the bottom electrode and a top electrode formed over the light-emissive layer.
    Type: Application
    Filed: November 17, 2008
    Publication date: May 20, 2010
    Inventors: Ronald S. Cok, John W. Hamer
  • Publication number: 20100109166
    Abstract: An active-matrix device includes a device substrate including a plurality of pixels formed thereon, each pixel having a separate control electrode, a plurality of chiplets having at least first and second corresponding chiplets disposed at different locations over the device substrate, a plurality of wires formed over the device substrate, each wire being connected to a connection pad and to a different pixel control electrode, and wherein the shape of at least one of the wires connecting a connection pad for the first chiplet is different from the shape of at least one of the wires connecting a corresponding connection pad for the second chiplet.
    Type: Application
    Filed: November 4, 2008
    Publication date: May 6, 2010
    Inventors: Ronald S. Cok, Dustin L. Winters, John W. Hamer, Todd M. Spath
  • Publication number: 20100073338
    Abstract: A method of controlling an RGBW electroluminescent display system that receives a three-component input image signal having triplets of intensity values in an image range and a highlight range includes transforming at least one of the triplets having an intensity value within the image range to a four-or-more-component drive signal to produce a luminance less than the sum of the corresponding luminance values of the red, green and blue light-emitting elements and transforming at least one of the intensity values within a triplet having an intensity value within the highlight range to a four-or-more-component drive signal to produce a luminance greater than the sum of the corresponding luminance values of the red, green, and blue light-emitting elements.
    Type: Application
    Filed: September 24, 2008
    Publication date: March 25, 2010
    Inventors: Michael E. Miller, Paula J. Alessi, John W. Hamer, Ronald S. Cok
  • Publication number: 20100039030
    Abstract: An electroluminescent device having a plurality of current driven pixels arranged in rows and columns, such that when current is provided to a pixel it produces light, including each pixel having first and second electrodes and current responsive electroluminescent media disposed between the first and second electrodes; at least one chiplet having a thickness less than 20 micrometers; including transistor drive circuitry for controlling the operation of at least four pixels, the chiplet being mounted on a substrate and having connection pads; a planarization layer disposed over at least a portion of the chiplet; a first conductive layer over the planarization layer and connected to at least one of the connection pads; and a structure for providing electrical signals through the first conductive layer and at least one of the connection pads of the chiplet so that the transistor drive circuitry of the chiplet controls current to the four pixels.
    Type: Application
    Filed: August 14, 2008
    Publication date: February 18, 2010
    Inventors: Dustin L. Winters, John W. Hamer, Gary Parrett, Chrstopher Bower, Etienne Menard
  • Publication number: 20100039357
    Abstract: A display device includes: a substrate; one or more pixels arranged on the substrate, each pixel including a control electrode; a wiring layer located over the substrate, the wiring layer having a continuous line and a discontinuous pass-thru line formed therein. The active-matrix device includes at least one chiplet located over the substrate and including first, second, third, and control connection pads including; a control line electrically connecting the control connection pad to the control electrode; a first end of the discontinuous pass-thru line connected to the first connection pad and a second end of the discontinuous pass-thru line connected to the second connection pad; circuitry electrically connecting the first and second connection pads; and the continuous line electrically connected to the third connection pad, wherein the continuous line extends to opposite sides of the chiplet.
    Type: Application
    Filed: August 14, 2008
    Publication date: February 18, 2010
    Inventors: Ronald S. Cok, John W. Hamer, Dustin L. Winters
  • Patent number: 7642997
    Abstract: An apparatus for selecting a stressing voltage for compensating for changes in the threshold voltages (Vth) for drive transistors in pixel drive circuits in an active matrix OLED display having a plurality of OLED light-emitting pixels arranged in an array is disclosed.
    Type: Grant
    Filed: June 28, 2006
    Date of Patent: January 5, 2010
    Assignee: Eastman Kodak Company
    Inventors: John W. Hamer, Gary Parrett
  • Publication number: 20090322649
    Abstract: A tiled display comprising: a plurality of display tiles aligned so that they provide the emissive image area; each display tile including: a plurality of light-emitting pixels arranged in groups of pixels; a plurality of sequentially arranged pixel drive circuits and each pixel drive circuit being electrically connected to a particular group of pixels for controlling the light emission of such pixels; one or more signal communication line(s) for providing data for controlling the operation of each pixel drive circuit; and each pixel drive circuit controlling the light emission of its corresponding group of pixels and providing information to the next sequential pixel drive circuit to cause such next sequential pixel drive circuit to respond to its corresponding data to control the operation of its group of light-emitting pixels and repeating this operation until a predetermined number of pixel drive circuits have caused the desired light emission.
    Type: Application
    Filed: June 30, 2008
    Publication date: December 31, 2009
    Inventors: John W. Hamer, Dustin L. Winters
  • Patent number: 7636074
    Abstract: An apparatus for determining an adjustment to a signal voltage for compensating for changes in the threshold voltage (Vth) for a drive transistor in a pixel drive circuit in an active matrix OLED display having at least one OLED light-emitting pixel, comprising: the pixel drive circuit having a data line, a power supply line, a drive transistor; the drive transistor being electrically connected to the power supply line and to the OLED light-emitting pixel; the switch transistor being electrically connected to the gate electrode of the drive transistor and to the data line; first means for applying a first voltage to the power supply line; second means for applying a second voltage to the power supply line opposite in polarity to the first voltage; third means for producing a threshold-voltage-related signal on the data line; and fourth means responsive to the threshold-voltage-related signal for calculating the adjustment to the signal voltage.
    Type: Grant
    Filed: June 28, 2006
    Date of Patent: December 22, 2009
    Assignee: Eastman Kodak Company
    Inventors: John W. Hamer, Gary Parrett
  • Publication number: 20090295422
    Abstract: A method of compensating for changes in the characteristics of transistors and electroluminescent devices in an electroluminescent display, includes: providing an electroluminescent display having a two-dimensional array of subpixels arranged forming each pixel having at least three subpixels of different colors, with each having an electroluminescent device and a drive transistor, wherein each electroluminescent device is driven by the corresponding drive transistor; providing in each pixel a readout circuit for one of the subpixels of a specific color having a first readout transistor and a second readout transistor connected in series; using the readout circuit to derive a correction signal based on the characteristics of at least one of the transistors in the specific color subpixel, or the electroluminescent device in the specific color subpixel, or both; and using the correction signal to adjust the drive signals.
    Type: Application
    Filed: May 29, 2008
    Publication date: December 3, 2009
    Inventors: John W. Hamer, Dustin L. Winters, Charles I. Levey