Abstract: 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.

Abstract: 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.

Abstract: What is disclosed are systems and methods of compensation of images produced by active matrix light emitting diode device (AMOLED) and other emissive displays. Anomalies in luminance produced by pixel circuits and bias currents produced by current biasing circuits for driving current biased voltage programmed pixels are corrected through calibration and compensation while re-using existing data or other lines that can be controlled individually to perform said calibration and compensation.

Abstract: A system for driving a display that includes a plurality of pixel circuits arranged in an array, each of the pixel circuits including a light emitting device and a driving transistor for conveying a driving current through the light emitting device. Methods of measuring characteristics of circuit elements of pixels sharing a monitor line include the control of biasing to selectively turn off circuit elements or render their response known while measuring other circuit elements of interest.

Abstract: 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.

Abstract: 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.

Abstract: What is disclosed are systems and methods of optical feedback for pixel identification, evaluation, and calibration for active matrix light emitting diode device (AMOLED) and other emissive displays. Optical feedback is utilized to calibrate pixel whose output luminance exceeds a threshold difference from a reference value, and may include the use of sparse pixel activation to ensure pixel identification and luminance measurement, as well as a coarse calibration procedure for programming the starting calibration data for a fine calibration stage.

Abstract: A system uses 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 by dividing each frame into at least first and second sub-frames, supplying the image data during one of the sub-frames, supplying compensation data during the other of the sub-frames, compensating image data based on the compensation data, and supplying each pixel with a drive current that is based on the compensated image data during each frame. The compensated image data may be supplied from a driver having a preselected data resolution, and the system determines whether the compensated image data is greater than the data resolution of the driver, and if the compensated image data is greater than the data resolution of the driver, transfers the excess compensated image data to a different sub-frame.

Abstract: 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.

Abstract: What is disclosed are display systems and methods of compensation of images produced by active matrix light emitting diode device (AMOLED) and other emissive displays. Anomalies in luminance produced by pixel circuits due to hysteresis effects are corrected through in-pixel compensation and resetting of the driving transistor.

Abstract: 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.

Abstract: A system for compensating the input signals to arrays of pixels that include semiconductor devices that age differently under different ambient and stress conditions. The system creates a library of compensation curves for different stress conditions of the semiconductor devices; identifies the stress conditions for at least a selected one of the semiconductor devices based on the rate of change or absolute value of at least one parameter of at least the selected device; selects a compensation curve for the selected device based on the identified stress conditions; calculates compensation parameters for the selected device based on the selected compensation curve; and compensates an input signal for the selected device based on the calculated compensation parameters.

Abstract: 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.

Abstract: 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.

Abstract: A method and system control an OLED display to achieve desired color points and brightness levels in an array of pixels in which each pixel includes at least three sub-pixels having different colors and at least one white sub-pixel. The method and system select a plurality of reference points in the pixel content domain with known color points and brightness levels. For each set of three sub-pixels of different colors, the method and system determine the share of each sub-pixel to produce the color point and brightness level of each selected reference point, and select the maximum share determined for each sub-pixel as peak brightness needed from that sub-pixel.

Abstract: A system for driving a display that includes a plurality of pixel circuits arranged in an array, each of the pixel circuits including a light emitting device and a driving transistor for conveying a driving current through the light emitting device. Each of a first plurality of supply lines is associated with at least one pixel circuit in a preselected segment of the array, the first plurality of supply lines providing driving currents to the at least one pixel circuit in the preselected segment. Each of a plurality of voltage supplies is configured to provide a supply voltage to the at least one pixel circuit in the preselected segment of the array, the voltage supplies being controllably coupled to the pixel circuits in the preselected segment of the array. A controller determines which of the plurality of voltage supplies to connect to the preselected segment of the array.

Abstract: What is disclosed are systems and methods of compensation of images produced by active matrix light emitting diode device (AMOLED) and other emissive displays. The electrical output of a pixel is compared with a reference value to adjust an input for the pixel. In some embodiments an integrator is used to integrate a pixel current and a reference current using controlled integration times to generate values for comparison.

Abstract: 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. In-pixel, charge-based compensation schemes are also discussed, which can be used with the external parameter extraction implementations.

Abstract: A system for controlling a display in which each pixel circuit comprises a light-emitting device, a drive transistor, a storage capacitor, a reference voltage source, and a programming voltage source. The storage capacitor stores a voltage equal to the difference between the reference voltage and the programming voltage, and a controller supplies a programming voltage that is a calibrated voltage for a known target current, reads the actual current passing through the drive transistor to a monitor line, turns off the light emitting device while modifying the calibrated voltage to make the current supplied through the drive transistor substantially the same as the target current, modifies the calibrated voltage to make the current supplied through the drive transistor substantially the same as the target current, and determines a current corresponding to the modified calibrated voltage based on predetermined current-voltage characteristics of the drive transistor.

Abstract: 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.