Global Oled Technology LLC

Eastman-kodak Company

Semprius, Inc.

Gary Parrett

John W Hamer

Christopher J White

Charles I Levey

Felipe A Leon

Dustin Lee Winters

Bruno Primerano

Ronald S Cok

Christopher Andrew Bower

Etienne Menard

Christopher Jason White

John William Hamer

Felipe Antonio Leon

Charles Iselin Levey

An electroluminescent (EL) panel with 2T1C subpixels is compensated for initial nonuniformity ('mura'). The current of each subpixel is measured at a selected time to provide a status signal representing the characteristics of the subpixel. A compensator receives a linear code value and changes it according to the status signals. A linear source driver drives the panel with the changed code values.

Electroluminescent display initial-nonuniformity-compensated drve signal

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 &#x394;V, &#x394;V, 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.

Compensated drive signal for electroluminescent display

A method of compensating for differences in characteristics of a plurality of electroluminescent (EL) subpixels having readout transistors, includes providing a first voltage source connected through a first switch to each subpixel's drive transistor and a second voltage source connected through a second switch to each subpixel's EL emitter; providing a current source connected through a third switch, and a current sink connected through a fourth switch, to the readout transistor; providing a test voltage to a subpixel; closing only the first and fourth switches and measuring the readout transistor voltage to provide a first signal representative of characteristics of the drive transistor; closing only the second and third switches and measuring the voltage to provide a second signal representative of characteristics of the EL emitter; repeating for each subpixel; and using the first and second signals for each subpixel to compensate for differences in characteristics of the EL subpixels.

Electroluminescent display with initial nonuniformity compensation

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.

Digital-drive electroluminescent display with aging compensation

Apparatus for providing an analog drive transistor control signal to the gate electrode of a drive transistor in a drive circuit that applies current to an EL device, the drive circuit including a first supply electrode of the drive transistor and the EL device connected to a second supply electrode of the drive transistor, comprising a measuring circuit for measuring the current passing through the supply electrodes at different times to provide an aging signal representing variations in the characteristics of the drive transistor and EL device caused by operation of the drive transistor and EL device over time; a compensator for changing a linear code value in response to the aging signal to compensate for the variations in the characteristics of the drive transistor and EL device; and a linear source driver for producing the analog drive transistor control signal in response to the changed linear code value.

Electroluminescent display compensated analog transistor drive signal

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.

OLED device with embedded chip driving

A light-emitting diode display device includes a transparent substrate; a plurality of chiplets located over the substrate between a transparent electrode and the substrate, each chiplet including drive circuitry for driving pixels to emit light and including a storage capacitor for storing charge and wherein light illumination of at least a portion of the drive circuit causes the capacitor to leak charge; a connection pad forming a first light shield separate from the drive circuitry located on the surface of each chiplet disposed over the drive circuitry and substantially shielding at least a portion of the drive circuitry from illumination, the connection pad electrically connected to the drive circuitry, and a second light shield disposed under the drive circuitry between the drive circuitry and the substrate to shield at least a portion of the drive circuitry from illumination.

Display device with chiplets and light shields

A method of compensating for changes in an OLED drive circuit, includes: providing a drive transistor; providing a first voltage source and a first switch; providing an OLED device connected to the drive transistor. Voltages are measured and used to compensate for changes in the OLED drive transistor.

OLED display with aging and efficiency compensation

An apparatus for selecting a stressing voltage for compensating for changes in the threshold voltages (V) 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.

Active matrix display compensation

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.

Active matrix display compensating apparatus

An electroluminescent display device comprising a plurality of pixels for generating light emission disposed over a substrate arranged in a matrix with rows and columns wherein each pixel includes first and second electrodes, an electroluminescent media disposed between the first and second electrodes, and at least one transistor electrically connected to the first electrode to regulate an electrical current flow to the organic electroluminescent media; a plurality of power lines arranged in either the row or column direction for supplying electrical current to the transistor of each pixel; at least one power bypass line electrically connected to two or more of the plurality of power lines; and the power lines formed from a patterned first conductor layer and the first electrodes and the power bypass lines formed from a patterned second conductor layer and wherein the first and second conductor layers are spaced apart from each other.

Electrical connection in OLED devices

Compensated drive circuit adjusting for changes in the threshold voltage of a drive transistor and for aging of an OLED device, comprising: a data line carrying analog data representative of the brightness level, and a select line; the drive transistor connected to a power supply and to the OLED device such that when the select line is activated and a voltage from the data line is applied to the gate electrode of such transistor and current proportional to the applied voltage will flow through the drain and source electrodes through the OLED device; circuitry for measuring first and second parameters associated with the drive circuitry and responsive to the measured first and second parameters for computing offset voltages to adjust for changes in the threshold voltage of the drive transistors and for aging of the OLED device.

Growing community of inventors

Rochester, NY, United States of America

Gary Parrett