Ignis Innovation Inc. Patent applications |
Patent application number | Title | Published |
20140329339 | DEFECT DETECTION AND CORRECTION OF PIXEL CIRCUITS FOR AMOLED DISPLAYS - A method of testing an array-based semiconductor device for defects during fabrication of the semiconductor device detects defects in said entities forming the semiconductor device at an intermediate stage in the fabrication of multiple types of entities forming the semiconductor device; determines whether the detected defects exceed preselected thresholds for the types of entities in which said detects are detected; if the detected defects do not exceed said preselected thresholds, continues the fabrication of the semiconductor device; and if the detected defects exceed said preselected thresholds, identifies the types of defects detected, repairs the identified defects, and continues the fabrication of the semiconductor device. | 11-06-2014 |
20140312330 | INSPECTION SYSTEM FOR OLED DISPLAY PANELS - A system for inspecting at least a portion of a display panel having thin film transistors (TFTs) and light emitting devicxes (OLEDs), during or immediately following fabrication, so that adjustments can be made to the fabrication procedures to avoid defects and non-uniformities. The system provides bonding pads connected to signal lines on at least portions of the display panel, and probe pads along selected edges of the display panel. The probe pads are coupled to the bonding pads through a plurality of multiplexers so that the number of probe pads is smaller than the number of bonding pads. | 10-23-2014 |
20140292342 | System And Method For Extracting Correlation Curves For An Organic Light Emitting Device - A system for determining the efficiency degradation of an organic light emitting device (OLED) in an array-based semiconductor device having an array of pixels that include OLEDs. The system determines the relationship between changes in an electrical operating parameter of the OLEDs and the efficiency degradation of said OLEDs, for at least one stress condition; measures a change in the electrical operating parameter of the OLEDs; determines the stress condition of at least one pixel or group of pixels in the semiconductor device; and uses the determined relationship and the determined stress condition to determine the efficiency degradation of the OLEDs corresponding to the measured change in the electrical operating parameter of the OLEDs. | 10-02-2014 |
20140285407 | SYSTEM AND METHODS FOR EXTRACTION OF THRESHOLD AND MOBILITY PARAMETERS IN AMOLED DISPLAYS - A system extracts effective parameters from a pixel circuit that includes a light emitting device, a drive device to provide a programmable drive current to the light emitting device, a programming input, and a storage device to store a programming signal. The system measures the value of at least one operating parameter of the pixel circuit at a plurality of levels, and then extracts the value of at least one related parameter of the pixel circuit, based on the measured values of the at least one operating parameter. The measured values of the operating parameter are translated to effective values for driving the pixel circuit, based on the extracted value. Then effective parameters for driving effective devices in the pixel circuit are extracted, based on the translated values, and stored for use in compensating input signals to the pixel circuit. | 09-25-2014 |
20140267372 | RE-INTERPOLATION WITH EDGE DETECTION FOR EXTRACTING AN AGING PATTERN FOR AMOLED DISPLAYS - A method that includes an initial uniform pixel measurement and interpolation followed by an edge detection algorithm to recognize the areas that contribute mostly to the estimation error due to the interpolation. The pixels on the detected edges and around their vicinity are also measured, and an aging pattern of the entire display is obtained by re-interpolating the entire measured set of data for the initially measured pixels as well as the pixels around the detected edges. The estimation error is reduced particularly in the presence of aging patterns having highly spatially correlated areas with distinctive edges. | 09-18-2014 |
20140267215 | AMOLED DISPLAYS WITH MULTIPLE READOUT CIRCUITS - The OLED voltage of a selected pixel is extracted from the pixel produced when the pixel is programmed so that the pixel current is a function of the OLED voltage. One method for extracting the OLED voltage is to first program the pixel in a way that the current is not a function of OLED voltage, and then in a way that the current is a function of OLED voltage. During the latter stage, the programming voltage is changed so that the pixel current is the same as the pixel current when the pixel was programmed in a way that the current was not a function of OLED voltage. The difference in the two programming voltages is then used to extract the OLED voltage. | 09-18-2014 |
20140266994 | STABLE DRIVING SCHEME FOR ACTIVE MATRIX DISPLAYS - A method and system for operating a pixel array having at least one pixel circuit is provided. The method includes repeating an operation cycle defining a frame period for a pixel circuit, including at each frame period, programming the pixel circuit, driving the pixel circuit, and relaxing a stress effect on the pixel circuit, prior to a next frame period. The system includes a pixel array including a plurality of pixel circuits and a plurality of lines for operation of the plurality of pixel circuits. Each of the pixel circuits includes a light emitting device, a storage capacitor, and a drive circuit connected to the light emitting device and the storage capacitor. The system includes a drive for operating the plurality of lines to repeat an operation cycle having a frame period so that each of the operation cycle comprises a programming cycle, a driving cycle and a relaxing cycle for relaxing a stress on a pixel circuit, prior to a next frame period. | 09-18-2014 |
20140252988 | PIXEL CIRCUITS FOR AMOLED DISPLAYS - The OLED voltage of a selected pixel is extracted from the pixel produced when the pixel is programmed so that the pixel current is a function of the OLED voltage. One method for extracting the OLED voltage is to first program the pixel in a way that the current is not a function of OLED voltage, and then in a way that the current is a function of OLED voltage. During the latter stage, the programming voltage is changed so that the pixel current is the same as the pixel current when the pixel was programmed in a way that the current was not a function of OLED voltage. The difference in the two programming voltages is then used to extract the OLED voltage. | 09-11-2014 |
20140232623 | COMPENSATION TECHNIQUE FOR LUMINANCE DEGRADATION IN ELECTRO-LUMINANCE DEVICES - A method and system for compensation for luminance degradation in electro-luminance devices is provided. The system includes a pixel circuit having a light emitting device, a storage capacitor, a plurality of transistors, and control signal lines to operate the pixel circuit. The storage capacitor is connected or disconnected to the transistor and a signal line(s) when programming and driving the pixel circuit. | 08-21-2014 |
20140217409 | THIN FILM TRANSISTOR - A thin film transistor comprises a semiconductor layer; first and second dielectric layers disposed on opposite sides of the semiconductor layer; a first metal layer forming first and second terminals on the opposite side of the first dielectric layer from the semiconductor layer, one of said first and second terminals extending through said first dielectric layer into contact with the semiconductor layer, the first and second terminals and the first dielectric layer forming a capacitor; and a second metal layer forming a third terminal on the opposite side of the second dielectric layer from the semiconductor layer. The first and second terminals may be source and drain terminals, and the third terminal may be a gate terminal. The first metal layer may be divided to form the first and second terminals. The third terminal may be shared with one of the first and second terminals. | 08-07-2014 |
20140198092 | DRIVING SCHEME FOR EMISSIVE DISPLAYS PROVIDING COMPENSATION FOR DRIVING TRANSISTOR VARIATIONS - Systems and methods detect and compensate for process or performance-related non-uniformities and/or degradation in displays. The systems and methods can compare a device current with one or more reference currents to generate an output signal indicative of the difference between the device and reference currents. This output voltage can be amplified, and quantized and then be used to determine how the device current differs from the reference current and to adjust the programming voltage for the device of interest accordingly. | 07-17-2014 |
20140168203 | METHOD AND SYSTEM FOR PROGRAMMING, CALIBRATING AND DRIVING A LIGHT EMITTING DEVICE DISPLAY - A method and system for programming, calibrating and driving a light emitting device display is provided. The system may include extracting a time dependent parameter of a pixel for calibration. | 06-19-2014 |
20140160093 | PIXEL CIRCUITS FOR AMOLED DISPLAYS - A system is provided for controlling an array of pixels in a display in which each pixel includes a light-emitting device and a reference voltage source that controllably supplies a reference voltage having a magnitude that turns off the light-emitting device. While the reference voltage is coupled to a drive transistor, a control voltage is supplied to the gate of the drive transistor to cause the drive transistor to transfer to a node common to the drive transistor and the light-emitting device, a voltage that is a function of the threshold voltage and mobility of the drive transistor. During an emission cycle, the current conveyed through the light emitting device via the drive transistor is controlled by a voltage stored in the storage capacitor, which is a function of the threshold voltage and mobility of the drive transistor so that the current supplied to the light-emitting device remains stable. | 06-12-2014 |
20140159996 | METHOD AND SYSTEM FOR PROGRAMMING, CALIBRATING AND DRIVING A LIGHT EMITTING DEVICE DISPLAY - A method and system for programming, calibrating and driving a light emitting device display is provided. The system may include extracting a time dependent parameter of a pixel for calibration. | 06-12-2014 |
20140132581 | VOLTAGE PROGRAMMED PIXEL CIRCUIT, DISPLAY SYSTEM AND DRIVING METHOD THEREOF - A voltage programmed pixel circuit, display system having the pixel circuit and driving method thereof is provided. The pixel circuit includes a light emitting device, a driving transistor connected to the light emitting device and a programming circuit. The programming circuit adjusts a pixel current during a programming cycle of the pixel circuit. | 05-15-2014 |
20140111567 | SYSTEM AND METHOD FOR COMPENSATION OF NON-UNIFORMITIES IN LIGHT EMITTING DEVICE DISPLAYS - A display degradation compensation system and method for adjusting the operating conditions for pixels in an OLED display to compensate for non-uniformity or aging of the display. The system or method sets an initial value for at least one of peak luminance and an operating condition, calculates compensation values for the pixels in the display, determines the number of pixels having compensation values larger than a predetermined threshold compensation value, and if the determined number of pixels having compensation values larger than said predetermined threshold value is greater than a predetermined threshold number, adjusts the set value until said determined number of pixels is less than said predetermined threshold number. | 04-24-2014 |
20140104325 | STABLE FAST PROGRAMMING SCHEME FOR DISPLAYS - A technique for improving the spatial and/or temporal uniformity of a light-emitting display by providing a faster calibration of reference current sources and reducing the noise effect by improving the dynamic range, despite instability and non-uniformity of the transistor devices. A calibration circuit for a display panel having an active area having a plurality of light emitting devices arranged on a substrate, and a peripheral area of the display panel separate from the active area is provided. The calibration circuit includes a first row of calibration current source or sink circuits and a second row of calibration current source or sink circuits. A first calibration control line is configured to cause the first row of calibration current source or sink circuits to calibrate the display panel with a bias current while the second row of calibration current source or sink circuits is being calibrated by a reference current. A second calibration control line is configured to cause the second row of calibration current source or sink circuits to calibrate the display panel with the bias current while the first row of calibration current source or sink circuits is being calibrated by the reference current. | 04-17-2014 |
20140085359 | SYSTEM AND DRIVING METHOD FOR LIGHT EMITTING DEVICE DISPLAY - A light emitting device display, its pixel circuit and its driving technique is provided. The pixel includes a light emitting device and a plurality of transistors. A bias current and programming voltage data are provided to the pixel circuit in accordance with a driving scheme so that the current through the driving transistor to the light emitting device is adjusted. | 03-27-2014 |
20140085168 | METHOD AND SYSTEM FOR DRIVING AN ACTIVE MATRIX DISPLAY CIRCUIT - A method and system for driving an active matrix display is provided. The system includes a drive circuit for a pixel having a light emitting device. The drive circuit includes a drive transistor for driving the light emitting device. The system includes a mechanism for adjusting the gate voltage of the drive transistor. | 03-27-2014 |
20140084932 | SYSTEM AND METHODS FOR EXTRACTION OF THRESHOLD AND MOBILITY PARAMETERS IN AMOLED DISPLAYS - A system reads a desired circuit parameter from a pixel circuit that includes a light emitting device, a drive device to provide a programmable drive current to the light emitting device, a programming input, and a storage device to store a programming signal. One embodiment of the extraction system turns off the drive device and supplies a predetermined voltage from an external source to the light emitting device, discharges the light emitting device until the light emitting device turns off, and then reads the voltage on the light emitting device while that device is turned off. The voltages on the light emitting devices in a plurality of pixel circuits may be read via the same external line, at different times. | 03-27-2014 |
20140062993 | SYSTEM AND METHODS FOR EXTRACTION OF PARASITIC PARAMETERS IN AMOLED DISPLAYS - A system reads a desired circuit parameter from a pixel circuit that includes a light emitting device, a drive device to provide a programmable drive current to the light emitting device, a programming input, and a storage device to store a programming signal. One embodiment of the extraction system extracts a parasitic capacitance value from a pixel circuit by measuring at least one parameter of the pixel circuit when in a first state having a first set of operating voltages and currents, measuring at least one parameter of the pixel circuit when in a second state having a second set of operating voltages and currents different from the first set, and extracting the value of a selected parasitic capacitance from the measurements. | 03-06-2014 |
20140043316 | SYSTEM AND METHODS FOR POWER CONSERVATION FOR AMOLED PIXEL DRIVERS - A system is provided for conserving energy in an AMOLED display having pixels that include a drive transistor and an organic light emitting device, and an adjustable source of a supply voltage for the drive transistor. The system monitors the content of a selected segment of the display, sets the supply voltage to the minimum supply voltage required for the current content of the selected segment of the display, determines whether the number of pixels requiring a supply voltage larger than the set value is greater than a predetermined threshold number, and, when the answer is negative, reduces the supply voltage by a predetermined step amount. | 02-13-2014 |
20140035488 | OLED LUMINANCE DEGRADATION COMPENSATION - A system and method are disclosed for determining a pixel capacitance. The pixel capacitance is correlated to a pixel age to determine a current correction factor used for compensating the pixel drive current to account for luminance degradation of the pixel that results from the pixel aging. | 02-06-2014 |
20140028738 | CIRCUIT AND METHOD FOR DRIVING AN ARRAY OF LIGHT EMITTING PIXELS - A technique for driving a column of pixels that include light emitting elements. The technique incorporates feedback data provided from feedback data sources connected to the data line and to feedback line of the array, pixel driving circuit with feedback path. The technique can also include block of the reference elements for input signal corrections. | 01-30-2014 |
20140028217 | Pixel Driver Circuit And Pixel Circuit Having The Pixel Driver Circuit - A pixel driver circuit for driving a light-emitting element and a pixel circuit having the pixel driver circuit are provided. The pixel driver circuit includes a data line, address lines, switch thin film transistors, feedback thin film transistors and drive thin film transistors. The pixel circuit may include an organic light emitting diode, which is driven by the pixel driver circuit. | 01-30-2014 |
20140015824 | SYSTEM AND METHODS FOR EXTRACTING CORRELATION CURVES FOR AN ORGANIC LIGHT EMITTING DEVICE - A system and method for determining and applying characterization correlation curves for aging effects on an organic light organic light emitting device (OLED) based pixel is disclosed. A first stress condition is applied to a reference pixel having a drive transistor and an OLED. An output voltage based on a reference current is measured periodically to determine an electrical characteristic of the reference pixel under the first predetermined stress condition. The luminance of the reference pixel is measured periodically to determine an optical characteristic of the reference pixel. A characterization correlation curve corresponding to the first stress condition including the determined electrical and optical characteristic of the reference pixel is stored. Characterization correlation curves for other predetermined stress conditions are also stored based on application of the predetermined stress conditions on other reference pixels. The stress condition of an active pixel is determined and a compensation voltage is determined by correlating the stress condition of the active pixel with the curves of the predetermined stress conditions. | 01-16-2014 |
20130314394 | DISPLAY SYSTEMS WITH COMPENSATION FOR LINE PROPAGATION DELAY - A method for characterizing and eliminating the effect of propagation delay on data and monitor lines of AMOLED panels is introduced. A similar technique may be utilized to cancel the effect of incomplete settling of select lines that control the write and read switches of pixels on a row. | 11-28-2013 |
20130307834 | SYSTEM AND METHODS FOR EXTRACTION OF THRESHOLD AND MOBILITY PARAMETERS IN AMOLED DISPLAYS - Disclosed is a system and method to improve the extraction of transistor and OLED parameters in an AMOLED display for compensation of programming voltages to improve image quality. A pixel circuit includes an organic light emitting device, a drive device to provide a programmable drive current to the light emitting device, a programming input to provide the programming signal, and a storage device to store the programming signal. A charge-pump amplifier has a current input and a voltage output. The charge-pump amplifier includes an operational amplifier in negative feedback configuration. The feedback is provided by a capacitor connected between the output and the inverting input of the operational amplifier. A common-mode voltage source drives the non-inverting input of the operational amplifier. An electronic switch is coupled across the capacitor to reset the capacitor. A switch module including the input is coupled to the output of the pixel circuit and an output is coupled to the input of the charge-pump amplifier. The switch module includes a set of electronic switches that may be controlled by external control signals to steer current in and out of the pixel circuit and provide a discharge path between the pixel circuit and the charge-pump amplifier and isolating the charge-pump amplifier from the pixel circuit. A controller is coupled to the pixel circuit, charge-pump amplifier and the switch module. The controller controls input signals to the pixel circuit, charge-pump amplifier and switch module in a predetermined sequence to produce an output voltage value which is a function of a parameter of the pixel circuit. The sequence includes providing a program voltage to the programming input to either pre-charge an internal capacitance of the pixel circuit to a charge level and transfer the charge to the charge-pump amplifier via the switch module to generate the output voltage value or provide a current from the pixel circuit to the charge-pump amplifier via the switch module to produce the output voltage value by integration over a certain period of time. | 11-21-2013 |
20130300724 | PIXEL CIRCUITS INCLUDING FEEDBACK CAPACITORS AND RESET CAPACITORS, AND DISPLAY SYSTEMS THEREFORE - A display with a pixel circuit for driving a current-driven emissive element includes a feedback capacitor in series between the emissive element and a programming node of the pixel circuit. During driving, variations in the operating voltage of the emissive element due to variations in the current conveyed through the emissive element by a driving transistor are accounted for. The feedback capacitor generates voltage adjustments at the programming node that correspond to the variations at the emissive element, and thus reduces variations in light emission. A reset capacitor connected to a select line is selectively connected to the gate terminal of the driving transistor and resets the driving transistor prior to programming. The select line adjusts the voltage on the gate terminal to reset the driving transistor by the capacitive coupling of the select line to the gate terminal created by the reset capacitor. | 11-14-2013 |
20130285537 | HIGH RESOLUTION DISPLAY ARCHITECTURE - An arrangement for a high resolution active matrix display includes organic emissive layers of distinct colors each deposited across continuous regions so as to include more than one pixel emissive region. Color filters are situated to partially block light from at least some of the emissive regions such that primary additive colors are transmitted from distinct subsets of pixels. The emissive layers may be deposited in alternating parallel stripes along rows or columns of the display, or may be oriented perpendicularly with respect to one another such that the emissive layers overlap in the emissive regions of at least some pixels. In some examples, red, green, and blue of pixels are arranged in regular patterns across the display and with the emissive regions for the blue pixels forming a relatively larger area of the display than either the red or green pixels. | 10-31-2013 |
20130257845 | RESETTING CYCLE FOR AGING COMPENSATION IN AMOLED DISPLAYS - A method of voltage-programming a pixel circuit in a display panel to remove, before programming the pixel circuit, effects due to short-term effects such as caused by fast light transitions or effects due to previous pixel circuit measurements such as charge trapping. During a resetting cycle, the pixel circuit is programmed with a reset voltage value corresponding to a maximum or a minimum voltage value. Then, during a calibration cycle, the pixel circuit is programmed with a calibration voltage based on previously extracted data for the pixel circuit, a pixel current of the pixel circuit is measured, and the extracted data for the pixel circuit is updated based on the measured pixel current. Then, the pixel circuit is programmed with a video data that is calibrated with the updated extracted data. The pixel circuit is finally driven according to the programmed video data and emits a commensurate amount of light. | 10-03-2013 |
20130235023 | SYSTEM AND METHODS FOR AGING COMPENSATION IN AMOLED DISPLAYS - A voltage-programmed display system allows measurement of effects on pixels in a panel that includes both active pixels and reference pixels coupled to a supply line and a programming line. The reference pixels are controlled so that they are not subject to substantial changes due to aging and operating conditions over time. A readout circuit is coupled to the active pixels and the reference pixels for reading at least one of current, voltage or charge from the pixels when they are supplied with known input signals. The readout circuit is subject to changes due to aging and operating conditions over time, but the readout values from the reference pixels are used to adjust the readout values from the active pixels to compensate for the unwanted effects. | 09-12-2013 |
20130201223 | DRIVING SYSTEM FOR ACTIVE-MATRIX DISPLAYS - Raw grayscale image data, representing images to be displayed in successive frames, is used to drive a display having pixels that include a drive transistor and an organic light emitting device by dividing each frame into at least first and second-frames, and supplying each pixel with a drive current that is higher in the first sub-frame than in the second sub-frame for raw grayscale values in a first preselected range, and higher in the second sub-frame than in the first sub-frame for raw grayscale values in a second preselected range. The display may be an active matrix display, such as an AMOLED display. | 08-08-2013 |
20130201173 | SYSTEM AND METHODS FOR EXTRACTION OF THRESHOLD AND MOBILITY PARAMETERS IN AMOLED DISPLAYS - A system to improve the extraction of transistor and OLED parameters in an AMOLED display includes a pixel circuit having an organic light emitting device, a drive device to provide a programmable drive current to the light emitting device, a programming input to provide the programming signal, and a storage device to store the programming signal. A charge-pump amplifier has a current input and a voltage output. The charge-pump amplifier includes an operational amplifier in negative feedback configuration. The feedback is provided by a capacitor connected between the output and the inverting input of the operational amplifier. A common-mode voltage source drives the non-inverting input of the operational amplifier. An electronic switch is coupled across the capacitor to reset the capacitor. A switch module including the input is coupled to the output of the pixel circuit and an output is coupled to the input of the charge-pump amplifier. | 08-08-2013 |
20130162507 | METHOD AND SYSTEM FOR PROGRAMMING AND DRIVING ACTIVE MATRIX LIGHT EMITTING DEVICE PIXEL HAVING A CONTROLLABLE SUPPLY VOLTAGE - Method and system for programming and driving active matrix light emitting device pixel is provided. The pixel is a voltage programmed pixel circuit, and has a light emitting device, a driving transistor and a storage capacitor. The pixel has a programming cycle having a plurality of operating cycles, and a driving cycle. During the programming cycle, the voltage of the connection between the OLED and the driving transistor is controlled so that the desired gate-source voltage of a driving transistor is stored in a storage capacitor. | 06-27-2013 |
20130147764 | Multi-functional active matrix organic light-emitting diode display - A multi-functional active matrix display comprises a transparent front sheet, a semi-transparent layer of light emissive devices adjacent the rear side of the front sheet and forming a matrix of display pixels, and a solar cell layer located behind the light emissive devices for converting both ambient light and internal light7 from the light emissive devices into electrical energy, the solar cell layer including an array of electrodes on the front surface of the solar cell layer for use in detecting the location of a change in the amount of light impinging on a portion of the front surface of the solar cell layer. | 06-13-2013 |
20130112960 | HIGH RESOLUTION PIXEL ARCHITECTURE - A pixel structure comprises a substantially transparent substrate, a drive transistor formed on the substrate, an organic light emitting device formed on the opposite side of the drive transistor from the substrate, a reflective layer disposed between the light emitting device and the drive transistor and having a reflective surface facing the light emitting device. The reflective layer forms an opening offset from the drive transistor for passing light emitted by the light emitting device to the substrate. At least a portion of the reflective layer is preferably concave in shape to direct reflected light from the light emitting device back onto the light-emitting device. | 05-09-2013 |
20130100173 | SYSTEMS AND METHODS FOR OPERATING PIXELS IN A DISPLAY TO MITIGATE IMAGE FLICKER - Circuits for programming a circuit with decreased programming time are provided. Such circuits include a storage device such as a capacitor for storing display information and for ensuring a driving device such as a driving transistor drives a light emitting device according to the display information. The present disclosure provides driving schemes for decreasing flickering perceived while displaying video content by introducing idle phases in between in emission phases to increase the effective refresh rate of a display. Driving schemes are also disclosed for reducing the effects of cross-talk by ensuring that programming information is refreshed in a display array that utilizes a driver connected to multiple data lines via a multiplexer. | 04-25-2013 |
20130099692 | SYSTEM AND METHOD FOR FAST COMPENSATION PROGRAMMING OF PIXELS IN A DISPLAY - Circuits for programming a circuit with decreased programming time are provided. Such circuits include a storage device such as a capacitor for storing display information and for ensuring a driving device such as a driving transistor drives a light emitting device according to the display information. To increase programming time, the pixel circuits may be pre-charged or a biasing current may be applied to charge and/or discharge a data line and/or the driving device. Aspects of the present disclosure allow for the biasing current to drain partially through the storage device to allow the portion of the biasing current applied to the driving device to remain small while the data line discharges. Furthermore, the present disclosure provides display architectures and operation schemes for display arranged in segments each including a plurality of pixel circuits. | 04-25-2013 |
20130088482 | METHOD AND SYSTEM FOR DRIVING AN ACTIVE MATRIX DISPLAY CIRCUIT - A method and system for driving an active matrix display is provided. The system includes a drive circuit for a pixel having a light emitting device. The drive circuit includes a drive transistor for driving the light emitting device. The system includes a mechanism for adjusting the gate voltage of the drive transistor. | 04-11-2013 |
20130057595 | OLED LUMINANCE DEGRADATION COMPENSATION - A system and method are disclosed for determining a pixel capacitance. The pixel capacitance is correlated to a pixel age to determine a current correction factor used for compensating the pixel drive current to account for luminance degradation of the pixel that results from the pixel aging. | 03-07-2013 |
20130032831 | ORGANIC LIGHT EMITTING DIODE AND METHOD OF MANUFACTURING - Aspects of the present disclosure provide for manufacturing an organic light emitting diode (OLED) by forming two terminals of the OLED on two substrates of the display, and then depositing a plurality of layers of the OLED on one or both of the two terminals to form a first portion and a second portion of the OLED on each substrate. The two portions are joined together to form an assembled OLED. The deposition of the two portions can be stopped with each portion having approximately half of a common layer exposed. The two portions can then be aligned to be joined together and an annealing process can be employed to join together the two parts of the common layer and thereby form the OLED. | 02-07-2013 |
20130032784 | THIN FILM TRANSISTOR INCLUDING A NANOCONDUCTOR LAYER - A thin film transistor having a channel region including a nanoconductor layer. The nanoconductor layer can be a dispersed monolayer of nanotubes or nanowires formed of carbon. The thin film transistor generally includes a gate terminal insulated by a dielectric layer. The nanoconductor layer is placed on the dielectric layer and a layer of semiconductor material is developed over the nanoconductor layer to form the channel region of the thin film transistor. A drain terminal and a source terminal are then formed on the semiconductor layer. At low field effect levels, the operation of the thin film transistor is dominated by the semiconductor layer, which provides good leakage current performance. At high field effect levels, the charge transfer characteristics of the channel region are enhanced by the nanoconductor layer such that the effective mobility of the thin film transistor is enhanced. | 02-07-2013 |
20130027381 | METHOD AND SYSTEM FOR PROGRAMMING, CALIBRATING AND DRIVING A LIGHT EMITTING DEVICE DISPLAY - A method and system for programming, calibrating and driving a light emitting device display is provided. The system may include extracting a time dependent parameter of a pixel for calibration. | 01-31-2013 |
20120299978 | SYSTEMS AND METHODS FOR AGING COMPENSATION IN AMOLED DISPLAYS - Circuits for programming, monitoring, and driving pixels in a display are provided. Circuits generally include a driving transistor to drive current through a light emitting device according to programming information which is stored on a storage device, such as a capacitor. One or more switching transistors are generally included to select the circuits for programming, monitoring, and/or emission. Circuits advantageously incorporate emission transistors to selectively couple the gate and source terminals of a driving transistor to allow programming information to be applied to the driving transistor independently of a resistance of a switching transistor. | 11-29-2012 |
20120299973 | Adaptive Feedback System For Compensating For Aging Pixel Areas With Enhanced Estimation Speed - A local priority-based scanning scheme that focuses scanning to areas of a display panel whose measured characteristics are under continuous change (e.g., aging or relaxation). The algorithm identifies areas or regions needing compensation, using a current measurement from a single pixel in an area as a candidate to determine whether the rest of the region needs further compensation. The algorithm thus detects newly changed areas quickly, focusing time-consuming measurements on those areas that need high attention. Optionally, neighboring pixels sharing the same state (e.g., aging or overcompensated) as the measured pixel can be adjusted automatically given the likelihood that the neighboring pixels will also require compensation if the measured pixel needs compensation. | 11-29-2012 |
20120293481 | SYSTEMS AND METHODS FOR DISPLAY SYSTEMS WITH DYNAMIC POWER CONTROL - Methods and systems to dynamically adjust a voltage supply of a display are provided. Systems are provided to receive a digital data input indicative of an amount of luminance to be emitted from the display, to determine a desired supply voltage to supply to the display based on the received digital data, and to adjust an adjustable voltage supply according to the determined desired supply voltage. Furthermore, the methods and systems disclosed herein provide for dynamically separately controlling supply voltages supplied to distinct subsections of the display. Systems and methods are also provided for operating a display device in an idle mode by turning off subsections of the display that would otherwise be shown dark and thereby save energy required to program the subsections with display information. | 11-22-2012 |
20120293478 | SYSTEM AND METHODS FOR EXTRACTION OF THRESHOLD AND MOBILITY PARAMETERS IN AMOLED DISPLAYS - Disclosed is a system and method to improve the extraction of transistor and OLED parameters in an AMOLED display for compensation of programming voltages to improve image quality. A pixel circuit includes an organic light emitting device, a drive device to provide a programmable drive current to the light emitting device, a programming input to provide the programming signal, and a storage device to store the programming signal. A charge-pump amplifier has a current input and a voltage output. The charge-pump amplifier includes an operational amplifier in negative feedback configuration. The feedback is provided by a capacitor connected between the output and the inverting input of the operational amplifier. A common-mode voltage source drives the non-inverting input of the operational amplifier. An electronic switch is coupled across the capacitor to reset the capacitor. A switch module including the input is coupled to the output of the pixel circuit and an output is coupled to the input of the charge-pump amplifier. The switch module includes a set of electronic switches that may be controlled by external control signals to steer current in and out of the pixel circuit and provide a discharge path between the pixel circuit and the charge-pump amplifier and isolating the charge-pump amplifier from the pixel circuit. A controller is coupled to the pixel circuit, charge-pump amplifier and the switch module. The controller controls input signals to the pixel circuit, charge-pump amplifier and switch module in a predetermined sequence to produce an output voltage value which is a function of a parameter of the pixel circuit. The sequence includes providing a program voltage to the programming input to either pre-charge an internal capacitance of the pixel circuit to a charge level and transfer the charge to the charge-pump amplifier via the switch module to generate the output voltage value or provide a current from the pixel circuit to the charge-pump amplifier via the switch module to produce the output voltage value by integration over a certain period of time. | 11-22-2012 |
20120169793 | METHOD AND SYSTEM FOR DRIVING AN ACTIVE MATRIX DISPLAY - A method and system for driving an active matrix display is provided. The system includes a drive circuit for a pixel having a light emitting device. The drive circuit includes a drive transistor for driving the light emitting device. The system includes a mechanism for adjusting the gate voltage of the drive transistor. | 07-05-2012 |
20120139955 | SYSTEM AND METHODS FOR THERMAL COMPENSATION IN AMOLED DISPLAYS - Disclosed is a circuit and technique to determine the temperature of an AMOLED display in order to calibrate programming data signals. The temperature of selected pixels of a plurality of pixels in an AMOLED display is measured via one of several disclosed methods. A thermal sensor for the selected pixels may be used. A measurement of output voltage data may be used to estimate temperature. A finite element analysis model may be used based on consumed power of the selected pixel. The temperature data for the selected pixel is then interpolated to the neighboring non-selected pixels to estimate the temperature of those pixels. | 06-07-2012 |
20120139894 | VOLTAGE-PROGRAMMING SCHEME FOR CURRENT-DRIVEN AMOLED DISPLAYS - A system and method for driving an AMOLED display is provided. The AMOLED display includes a plurality of pixel circuits. A voltage-programming scheme, a current-programming scheme or a combination thereof is applied to drive the display. Threshold shift information, and/or voltage necessary to obtain hybrid driving circuit may be acquired. A data sampling may be implemented to acquire a current/voltage relationship. A feedback operation may be implemented to correct the brightness of the pixel. | 06-07-2012 |
20120013581 | METHOD AND SYSTEM FOR DRIVING AN ACTIVE MATRIX DISPLAY CIRCUIT - A method and system for driving an active matrix display is provided. The system includes a drive circuit for a pixel having a light emitting device. The drive circuit includes a drive transistor for driving the light emitting device. The system includes a mechanism for adjusting the gate voltage of the drive transistor. | 01-19-2012 |
20120007842 | METHOD AND SYSTEM FOR PROGRAMMING AND DRIVING ACTIVE MATRIX LIGHT EMITTING DEVICE PIXEL HAVING A CONTROLLABLE SUPPLY VOLTAGE - Method and system for programming and driving active matrix light emitting device pixel is provided. The pixel is a voltage programmed pixel circuit, and has a light emitting device, a driving transistor and a storage capacitor. The pixel has a programming cycle having a plurality of operating cycles, and a driving cycle. During the programming cycle, the voltage of the connection between the OLED and the driving transistor is controlled so that the desired gate-source voltage of a driving transistor is stored in a storage capacitor. | 01-12-2012 |
20120001888 | VOLTAGE PROGRAMMED PIXEL CIRCUIT, DISPLAY SYSTEM AND DRIVING METHOD THEREOF - A voltage programmed pixel circuit, display system having the pixel circuit and driving method thereof is provided. The pixel circuit includes a light emitting device, a driving transistor connected to the light emitting device and a programming circuit. The programming circuit adjusts a pixel current during a programming cycle of the pixel circuit. | 01-05-2012 |
20110279488 | OLED LUMINANCE DEGRADATION COMPENSATION - A system and method are disclosed for determining a pixel capacitance. The pixel capacitance is correlated to a pixel age to determine a current correction factor used for compensating the pixel drive current to account for luminance degradation of the pixel that results from the pixel aging. | 11-17-2011 |
20110272695 | PIXEL HAVING AN ORGANIC LIGHT EMITTING DIODE AND METHOD OF FABRICATING THE PIXEL - A pixel having an organic light emitting diode (OLED) and method for fabricating the pixel is provided. A planarization dielectric layer is provided between a thin-film transistor (TFT) based backplane and OLED layers. A through via between the TFT backplane and the OLED layers forms a sidewall angle of less than 90 degrees to the TFT backplane. The via area and edges of an OLED bottom electrode pattern may be covered with a dielectric cap. | 11-10-2011 |
20110248980 | CIRCUIT AND METHOD FOR DRIVING AN ARRAY OF LIGHT EMITTING PIXELS - A technique for driving a column of pixels that include light emitting elements. The technique incorporates feedback data provided from feedback data sources connected to the data line and to feedback line of the array, pixel driving circuit with feedback path. The technique can also include block of the reference elements for input signal corrections. | 10-13-2011 |
20110227964 | LIFETIME UNIFORMITY PARAMETER EXTRACTION METHODS - A system and method for deriving a sequence of OLED non-uniformity test patterns. A pattern generator generates a full sequence of display patterns according to a transform function, such as a discrete cosine transformation or wavelet transformation. A driver drives a display with each of the sequence of patterns. A sensor senses a property of the display, such as a total current for the display, for each of the sequence of patterns. An extraction unit derives a pixel non-uniformity model using the sensed properties and an inverse of the transform function. Patterns that contribute less than a threshold amount to the non-uniformity model can be identified and deleted to derive a sparse sequence of patterns, which can be stored in a memory. The sparse sequence of patterns can be used to test the display and extract a set of pixel non-uniformity values. The pixel non-uniformity values can be used to generate a correction signal for the display. | 09-22-2011 |
20110199395 | SYSTEM AND METHOD FOR COMPENSATION OF NON-UNIFORMITIES IN LIGHT EMITTING DEVICE DISPLAYS - A system and method for operating a display at a constant luminance even as some of the pixels in the display are degraded over time. Each pixel in the display is configured to emit light when a voltage is supplied to the pixel's driving circuit, which causes a current to flow through a light emitting element. Degraded pixels are compensated by supplying their respective driving circuits with greater voltages. The display data is scaled by a compression factor less than one to reserve some voltage levels for compensating degraded pixels. As pixels become more degraded, and require additional compensation, the compression factor is decreased to reserve additional voltage levels for use in compensation. | 08-18-2011 |
20110193834 | PIXEL DRIVER CIRCUIT AND PIXEL CIRCUIT HAVING THE PIXEL DRIVER CIRCUIT - A pixel driver circuit for driving a light-emitting element and a pixel circuit having the pixel driver circuit are provided. The pixel driver circuit includes a data line, address lines, switch thin film transistors, feedback thin film transistors and drive thin film transistors. The pixel circuit may include an organic light emitting diode, which is driven by the pixel driver circuit. | 08-11-2011 |
20110191042 | SYSTEM AND METHODS FOR EXTRACTING CORRELATION CURVES FOR AN ORGANIC LIGHT EMITTING DEVICE - A system and method for determining and applying characterization correlation curves for aging effects on an organic light organic light emitting device (OLED) based pixel is disclosed. A first stress condition is applied to a reference pixel having a drive transistor and an OLED. An output voltage based on a reference current is measured periodically to determine an electrical characteristic of the reference pixel under the first predetermined stress condition. The luminance of the reference pixel is measured periodically to determine an optical characteristic of the reference pixel. A characterization correlation curve corresponding to the first stress condition including the determined electrical and optical characteristic of the reference pixel is stored. Characterization correlation curves for other predetermined stress conditions are also stored based on application of the predetermined stress conditions on other reference pixels. The stress condition of an active pixel is determined and a compensation voltage is determined by correlating the stress condition of the active pixel with the curves of the predetermined stress conditions. | 08-04-2011 |
20110141160 | COMPENSATION TECHNIQUE FOR LUMINANCE DEGRADATION IN ELECTRO-LUMINANCE DEVICES - A method and system for compensation for luminance degradation in electro-luminance devices is provided. The system includes a pixel circuit having a light emitting device, a storage capacitor, a plurality of transistors, and control signal lines to operate the pixel circuit. The storage capacitor is connected or disconnected to the transistor and a signal line(s) when programming and driving the pixel circuit. | 06-16-2011 |
20110134157 | SYSTEM AND METHODS FOR POWER CONSERVATION FOR AMOLED PIXEL DRIVERS - A circuit and method to improve energy conservation of an AMOLED display. The display includes a matrix of pixels each having an organic light emitting device coupled to a drive transistor. The brightness of the light emitting device is controlled by a programming voltage applied to the gate of the drive transistor. The supply voltage to the drive transistor is adjusted to different levels based on the required brightness of the pixel. Since the drive transistor operates in saturation mode, especially when maximum brightness is desired, the supply voltage may be reduced while maintaining the same brightness level. | 06-09-2011 |
20110134094 | SYSTEM AND DRIVING METHOD FOR ACTIVE MATRIX LIGHT EMITTING DEVICE DISPLAY - Active matrix light emitting device display and its driving technique is provided. The pixel includes a light emitting device and a plurality of transistors. A capacitor may be used to store a voltage applied to a driving transistor so that a current through the light emitting device is independent of any shifts of the transistor and light emitting device characteristics. A bias data and a programming data are provided to the pixel circuit in accordance with a driving scheme. | 06-09-2011 |
20110130981 | SYSTEM AND METHODS FOR AGING COMPENSATION IN AMOLED DISPLAYS - Methods and systems to provide baseline measurements for aging compensation for a display device are disclosed. An example display system has a plurality of active pixels and a reference pixel. Common input signals are provided to the reference pixel and the plurality of active pixels. The outputs of the reference pixel is measured and compared to the output of the active pixels to determine aging effects. The display system may also be tested applying a first known reference current to a current comparator with a second variable reference current and the output of a device under test such as one of the pixels. The variable reference current is adjusted until the second current and the output of the device under test is equivalent of the first current. The resulting current of the device under test is stored in a look up table for a baseline for aging measurements during the display system operation. The display system may also be tested to determine production flaws by determining anomalies such as short circuits in pixel components such as OLEDs and drive transistors. | 06-02-2011 |
20110128262 | HIGH RESOLUTION PIXEL ARCHITECTURE - A high resolution pixel using organic light emitting devices (OLEDs) in a staggered arrangement to increase aperture ratio is disclosed. The arrangement may be used with both bottom and top emission type pixels. The arrangement includes a first organic light emitting device emitting light of a first color. A second organic light emitting device emitting light of a second color is located in a bottom row under the first organic light emitting device. A third organic light emitting device emitting light of a third color is located in a top row with the first organic light emitting device. | 06-02-2011 |
20110109612 | SHARING SWITCH TFTS IN PIXEL CIRCUITS - A circuit and driving technique to improve the display resolution of an AMOLED display. Sharing of switch transistors between several sub-pixels in the display leads to improved manufacturing yield by minimizing the number of transistors used. The method also allows for conventional sequential scan driving to be used. The circuit includes a shared switch transistor connected between a voltage data line and a shared line that is connected to a reference voltage through a reference voltage transistor, a first pixel including a first light emitting device configured to be current driven by a first drive circuit connected to the shared line through a first storage device, a second pixel including a second light emitting device configured to be current driven by a second drive circuit connected to the shared line through a second storage device, and a reference current line configured to apply a bias current to the first and second drive circuits. | 05-12-2011 |
20110109350 | Stable Current Source for System Integration to Display Substrate - A technique to implement a stable and high impedance current sink or source onto a display substrate using a single device. The high output current source or sink circuit includes an input that receives a fixed reference current and provides the reference current to a node in the current source or sink circuit during a calibration operation of the current source or sink circuit. The circuit further includes a first transistor and a second transistor series-connected to the node such that the reference current adjusts the voltage at the node to allow the reference current to pass through the series-connected transistors during the calibration operation. The circuit includes one or more storage devices connected to the node, and an output transistor connected to the node to source or sink an output current from current stored in the one or more storage devices to a drive an active matrix display with a bias current corresponding to the output current. | 05-12-2011 |
20110109299 | Stable Fast Programming Scheme for Displays - A technique for improving the spatial and/or temporal uniformity of a light-emitting display by providing a faster calibration of reference current sources and reducing the noise effect by improving the dynamic range, despite instability and non-uniformity of the transistor devices. A calibration circuit for a display panel having an active area having a plurality of light emitting devices arranged on a substrate, and a peripheral area of the display panel separate from the active area is provided. The calibration circuit includes a first row of calibration current source or sink circuits and a second row of calibration current source or sink circuits. A first calibration control line is configured to cause the first row of calibration current source or sink circuits to calibrate the display panel with a bias current while the second row of calibration current source or sink circuits is being calibrated by a reference current. A second calibration control line is configured to cause the second row of calibration current source or sink circuits to calibrate the display panel with the bias current while the first row of calibration current source or sink circuits is being calibrated by the reference current. | 05-12-2011 |
20110069096 | Driving System For Active-Matrix Displays - A system is provided for using raw grayscale image data, representing images to be displayed in successive frames, to drive a display having pixels that include a drive transistor and an organic light emitting device. The system defines high and low ranges of raw grayscale image data, and determines whether the raw grayscale image data for each pixel falls within the high range or the low range. Raw grayscale image data that falls within the low range is converted to higher grayscale values, and the pixels are driven with currents corresponding to the higher grayscale values during time periods that are shorter than complete frame time periods. Raw grayscale image data that falls within the high range is converted to higher grayscale values, and the pixels are driven with currents corresponding to the higher grayscale values during time periods that are shorter than complete frame time periods and different from the time periods of the low range image data. When the raw grayscale image data is adjusted according to a preselected gamma curve before using that data to drive the pixels, the high and low ranges may be selected according to how well the gamma curve corrects the raw grayscale image data within the ranges. | 03-24-2011 |
20110012884 | METHOD AND SYSTEM FOR DRIVING A LIGHT EMITTING DEVICE DISPLAY - A method and system for driving a light emitting device display is provided. The system provides a timing schedule which increases accuracy in the display. The system may provide the timing schedule by which an operation cycle is implemented consecutively in a group of rows. The system may provide the timing schedule by which an aging factor is used for a plurality of frames. | 01-20-2011 |
20110012883 | METHOD AND SYSTEM FOR PROGRAMMING AND DRIVING ACTIVE MATRIX LIGHT EMITTING DEVICE PIXEL - Method and system for programming and driving active matrix light emitting device pixel is provided. The pixel is a voltage programmed pixel circuit, and has a light emitting device, a driving transistor and a storage capacitor. The pixel has a programming cycle having a plurality of operating cycles, and a driving cycle. During the programming cycle, the voltage of the connection between the OLED and the driving transistor is controlled so that the desired gate-source voltage of a driving transistor is stored in a storage capacitor. | 01-20-2011 |
20100315449 | COMPENSATION TECHNIQUE FOR COLOR SHIFT IN DISPLAYS - A system for maintaining a substantially constant display white point over an extended period of operation of a color display formed by an array of multiple pixels in which each of the pixels includes multiple subpixels having different colors, and each of the subpixels includes a light emissive device. The display is generated by energizing the subpixels of successively selected pixels, and the color of each selected pixel is controlled by the relatives levels of energization of the subpixels in the selected pixel. The degradation behavior of the subpixels in each pixel is determined, and the relative levels of energization of the subpixels in each pixel are adjusted to adjust the brightness shares of the subpixels to compensate for the degradation behavior of the subpixels. The brightness shares are preferably adjusted to maintain a substantially constant display white point. | 12-16-2010 |
20100207920 | LOW POWER CIRCUIT AND DRIVING METHOD FOR EMISSIVE DISPLAYS - A display system, a driver for driving the display array, method of operating the display system and a pixel circuit in the display system are provided. The driver includes: a bidirectional current source having a convertor coupling to a time-variant voltage, for converting the time-variant voltage to the current. The pixel circuit includes: a transistor for providing a pixel current to a light emitting device; and a storage capacitor electrically coupling to the transistor, the capacitor coupling to a time-variant voltage in a predetermined timing for providing a current based on the time-variant voltage. The method includes: in a first cycle in a programming operation, changing a time-variant voltage provided to a storage capacitor in a pixel circuit, from a reference voltage to a programming voltage, the storage capacitor electrically coupling to a driving transistor for driving a light emitting device; and in a second cycle in the programming operation, maintaining the time-variant voltage at the programming voltage. The method includes: in a programming operation, providing programming data to a pixel circuit from a data line, the pixel circuit including a transistor coupling to the data line and a storage capacitor; and in a driving operation, providing, to the storage capacitor in the pixel circuit via a power supply line, a time-variant voltage for turning on a light emitting device. The pixel circuit, which includes: an organic light emitting diode (OLED) device having an electrode and an OLED layer; and an inter-digitated capacitor having a plurality of layers. | 08-19-2010 |
20100039458 | SYSTEM AND DRIVING METHOD FOR LIGHT EMITTING DEVICE DISPLAY - A light emitting device display, its pixel circuit and its driving technique is provided. The pixel includes a light emitting device and a plurality of transistors. A bias current and programming voltage data are provided to the pixel circuit in accordance with a driving scheme so that the current through the driving transistor to the light emitting device is adjusted. | 02-18-2010 |
20100039453 | METHOD AND SYSTEM FOR DRIVING LIGHT EMITTING DISPLAY - A display system and its driving method is provided. The system includes: a driver for operating a panel having a plurality of pixels arranged by a plurality of first lines and at least one second line, the driver including: a driver output unit for providing to the panel a single driver output for activating the plurality of first lines, the single driver output being demultiplexed on the panel to activate each first line. The system includes: a driver for operating a panel having a plurality of pixels arranged by a plurality of data lines and at least one scan line, the driver including: a shift register unit including a plurality of shift registers; a latch and shift register unit including a plurality of latch and shift circuits for the plurality of shift registers, each storing an image signal from the corresponding shift register or shifting the image signal to a next latch and shift circuit; and a decoder unit including at least one decoder coupled to one of the latch and shift circuits, for decoding the image signal latched in the one of the latch and shift circuit to provide a driver output. The system includes: a driver for operating a panel having a plurality of pixels, the driver including: a plurality of multiplexers for a plurality of offset gamma curve sections, each offset gamma curve section having a first range less than a second range of a main gamma curve, at least one of offset gamma curve sections being offset by a predetermined voltage from a corresponding section of the main gamma curve; a plurality of decoders for the plurality of multiplexers; and an output buffer for providing a driver output based on the output from the decoder and the predetermined voltage. | 02-18-2010 |
20100033469 | METHOD AND SYSTEM FOR PROGRAMMING, CALIBRATING AND DRIVING A LIGHT EMITTING DEVICE DISPLAY - A method and system for programming, calibrating and driving a light emitting device display is provided. The system may include extracting a time dependent parameter of a pixel for calibration. | 02-11-2010 |
20090284501 | PIXEL DRIVER CIRCUIT AND PIXEL CIRCUIT HAVING THE PIXEL DRIVER CIRCUIT - A pixel driver circuit for driving a light-emitting element and a pixel circuit having the pixel driver circuit are provided. The pixel driver circuit includes a data line, address lines, switch thin film transistors, feedback thin film transistors and drive thin film transistors. The pixel circuit may include an organic light emitting diode, which is driven by the pixel driver circuit. | 11-19-2009 |
20090262101 | PIXEL CIRCUIT, DISPLAY SYSTEM AND DRIVING METHOD THEREOF - A display system and method for the same is provided. A display includes a plurality of pixels, each having a light emitting device and a driving transistor for driving the light emitting device, the driving transistor and the light emitting device being coupled in series between a first power supply and a second power supply. The method includes: at a first frame, programming a pixel with a first programming voltage different from a programming voltage for a valid image, and charging at least one of the first power supply and the second power supply so that at least one of the driving transistor and the light emitting device is under a negative bias. The pixel circuit includes: a light emitting device; a driving transistor for driving the light emitting device, the driving transistor having a gate terminal, a first terminal coupled to the light emitting device, and a second terminal; a storage capacitor; a first switch transistor coupled to a data line for providing a programming data and the gate terminal of the driving transistor; and a second switch transistor for reducing a threshold voltage shift of the driving transistor, the storage capacitor and the second switch transistor being coupled in parallel to the gate terminal of the driving transistor and the first terminal of the driving transistor. The method includes: at a first cycle, implementing an image display operation having programming the pixel circuit for a valid image and driving the light emitting device; and at a second cycle, implementing a relaxation operation for reducing a stress on the pixel circuit, including: selecting a relaxation switch transistor coupled to the storage capacitor in parallel. | 10-22-2009 |
20090262046 | HIGH APERTURE RATIO PIXEL LAYOUT FOR DISPLAY DEVICE - A display device, pixel layout and method of forming the same is provided. The display device includes: a plurality of pixels formed in a pixel array area; and a power supply grid for distributing power to the pixels. Each pixel has a light emitting device and a plurality of transistors. The power supply grid includes a first group of power supply lines and a second group of power supply lines. The first group of power supply lines extend across the pixel array area. The second group of power supply lines extends across the pixel array area and electrically contacts the first group of power supply lines in the pixel array area. Each pixel is coupled to at least one power supply line in the first group of power supply lines and the second group of power supply lines. | 10-22-2009 |
20090219273 | DISPLAY SYSTEM WITH A SOLAR CELL AND DEVICE HAVING THE SAME - A display system and a device having the display system are provided. The display system includes: a pixel area on which a pixel is formed; a substrate having a top side and a back side opposite to the top side, and a plurality of edges between the top side and the back side, the substrate being a main substrate on which the pixel area being formed or a sealing substrate; and a solar cell area having at least one solar cell integrated on a peripheral of the pixel area, the edge of the substrate or a combination thereof. The display system includes: a pixel area on a display substrate, including: a transparent electrode; and an emissive device for emitting a light, the transparent electrode and the emissive device being aligned in series on the display substrate, a solar cell placed behind the transparent electrode, for making the transparent electrode non-reflective to the emissive device. The device includes: the display system, and a chargeable power source electrically connected to the solar cell for supplying an operation power to the device. | 09-03-2009 |
20090212287 | THIN FILM TRANSISTOR AND METHOD FOR FORMING THE SAME - A thin film transistor (TFT) and the method of forming the same is provided. The method of forming the TFT on a surface of a substrate, includes the steps of: forming a gate electrode; deposing a gate dielectric on the gate electrode; forming a nanocrystalline silicon (nc-Si) layer and an amorphous silicon (a-Si:H) layer above the gate dielectric, so that the thickness of the nc-Si layer is less than 30 nm thereby reducing off-current; and forming a source/drain electrode. The TFT includes: a gate electrode on a substrate, a gate dielectric on the gate electrode; a nc-Si layer having a thickness less than 30 nm, thereby reducing off-current; an a-Si:H layer; and a source/drain electrode. | 08-27-2009 |