Global Oled Technology LLC

Eastman-kodak Company

Oledworks Gmbh

Charles I Levey

John W Hamer

Gary Parrett

Samuel Chen

Felipe A Leon

Christopher J White

Joseph Anthony Manico

John Randall Fredlund

Michael E Miller

Dustin Lee Winters

Scott B Chase

Allan F Camp

Vincent J Andrews

Christopher Jason White

Felipe Antonio Leon

An active-matrix display comprising a power source V; a pixel array of columns and rows, each light-emitting pixel having an individually controlled segmented electrode and an opposite electrode; a driving circuit comprising at least one data line that supplies a data signal for each pixel along a column, wherein the data signal controls the gate of a driving transistor whose source and drain are connected between the power source Vand the segmented electrode and at least one scan line that supplies a scan signal that controls the gate of a scan transistor that enables the loading of the data signal from the data line to the gate of the driving transistor for each pixel along a row; and a pixel control circuit in electrical contact with the segmented electrode wherein the pixel control circuit prevents light emission by the pixel based on the value of the data signal for that pixel. The pixel control circuit comprises a decision circuit which outputs a signal which controls a bypass transistor which prevents emission whenever the data signal indicates that the pixel should be non-emitting. This reduces crosstalk, particularly in OLED microdisplays.

Pixel circuit for crosstalk reduction

A method for making a printed wiring member including wire-bondable contact pads and wear-resistant connector pads, the method includes the steps of a) providing a blank printed wiring member comprising a copper foil laminated to a dielectric substrate; b) masking the blank printed wiring member to protect regions of the copper foil; c) removing copper in unprotected regions of the blank printed wiring member to form a patterned printed wiring member including contact pads and connector pads; d) depositing a nickel coating on the patterned printed wiring member using an electroless nickel deposition process; e) depositing a gold layer on the nickel coating using an electroless gold deposition process; and f) depositing palladium on the gold layer using an electroless palladium deposition process to improve wear resistance of the connector pads while preserving bondability of the contact pads.

Method of making bondable printed wiring member

A method for making a printed wiring member including wire-bondable contact pads and wear-resistant connector pads, the method includes a) providing a blank printed wiring member comprising a copper foil laminated to a dielectric substrate; b) masking the blank printed wiring member to protect regions of the copper foil; c) removing copper in unprotected regions of the blank printed wiring member to form a patterned printed wiring member including contact pads and connector pads; d) depositing a nickel coating on the patterned printed wiring member; e) electrolytically depositing a hard gold layer on the nickel coating; and f) depositing palladium on a surface of the hard gold layer to improve bondability of the contact pads while preserving wear resistance of the connector pads.

Method of making wear-resistant printed wiring member

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

A printed wiring member includes a dielectric substrate; a patterned copper layer formed on the dielectric substrate. The patterned copper layer includes i) contact pads for wire bonding; ii) connector pads for making electrical connection with an electrical connector; and iii) conductor traces between contact pads and corresponding connector pads. A nickel coating is formed on the contact pads and the connector pads, and a gold layer is formed on the nickel coating on the contact pads and the connector pads. A palladium deposit is formed on the gold layer on at least the connector pads.

Bondable printed wiring with improved wear resistance

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.

Compensation scheme for multi-color electroluminescent display

An electroluminescent (EL) subpixel, such as an organic light-emitting diode (OLED) subpixel, is compensated for aging effects such as threshold voltage Vshift, EL voltage Vshift, 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 Vshift 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.

Electroluminescent subpixel compensated drive signal

Inoperative or defective electroluminescent (EL) emitters in an EL display having a plurality of subpixels are detected. Current flow through a drive transistor in a subpixel is turned off, a selected test current is provided through the EL emitter in the subpixel using a current source, and the voltage at a second electrode of a readout transistor in the subpixel is measured to provide a status signal representative or characteristics of the selected EL emitter. The status signal for the subpixel is compared to the respective status signals of neighboring subpixels to determine whether the EL emitter in the subpixel is defective.

Defective emitter detection for electroluminescent display

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 Vshift, EL voltage Vshift, 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 Vshift 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.

Electroluminescent display compensated drive signal

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

A method of compensating for changes in the characteristics of transistors and EL devices in an EL display, includes providing an EL display having a two-dimensional array of EL devices arranged in rows and columns, wherein each EL device is driven by a drive circuit in response to a drive signal; providing a first drive circuit for an EL device having three transistors and providing a second drive circuit for an EL device having only two transistors, and wherein a first column in the display includes at least one first drive circuit and an adjacent second column includes at least one second drive circuit; deriving a correction signal based on the characteristics of a transistor in a first drive circuit, or the EL device; and using the correction signal to adjust the drive signals applied to the first drive circuit and one or more adjacent second drive circuits.

Electroluminescent display with interleaved 3T1C compensation

Compensating for changes in the threshold voltage of the drive transistor of an OLED drive circuit, the drive transistor includes a first electrode, second electrode, and gate electrode; connecting a first voltage source to the first electrode, and an OLED device to the second electrode and to a second voltage source; providing a test voltage to the gate electrode and connecting to the OLED drive circuit, a test circuit, that includes an adjustable current mirror causing voltage applied to the current mirror, to be at a first test level; providing a test voltage to the gate electrode of the drive transistor and connecting the test circuit to the OLED device producing a second test level after the drive transistor and the OLED device age; and using the first and second test levels to calculate changes in the voltage applied to the gate electrode of the drive transistor to compensate for drive transistor aging.

Active matrix display compensating method

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

A method of determining characteristics of transistors and electroluminescent devices, includes: providing an electroluminescent display; providing for pairs of electroluminescent devices drive circuits and a single readout line, each drive circuit including a readout transistor electrically connected to the readout line; providing a first voltage source; providing a second voltage source; providing a current source; providing a current sink; providing a test voltage source; providing a voltage measurement circuit; sequentially testing the drive transistors to provide a first signal representative of characteristics of the drive transistor of the first drive circuit and a second signal representative of characteristics of the drive transistor of the second drive circuit, whereby the characteristics of each drive transistor are determined; and simultaneously testing the first and second electroluminescent devices to provide a third signal representative of characteristics of the pair of electroluminescent devices, whereby the characteristics of both electroluminescent devices are determined.

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West Henrietta, NY, United States of America

Charles I Levey