# US 2014/0192101 A1 · Display apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0192101 A1 - Document ID: US20140192101A1 - Status: Published application - Kind: A1 - Application number: 14/209,244 - Filed: 2014-03-13 - Published: 2014-07-10 - Earliest claimed: 2011-10-14 - Assignees: Panasonic Corporation - Applicants: Panasonic Corporation - Inventors: Hitoshi TSUGE - Web page: https://patentgrep.com/patent/US20140192101A1 ## CPC - G09G 3/3291: in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements - G09G 3/3225: using an active matrix - G09G 3/2081: {with combination of amplitude modulation and time modulation (space and time error diffusion G09G3/2066)} - G09G 2300/0819: used for counteracting undesired variations, e.g. feedback or autozeroing - G09G 2300/0852: being a dynamic memory with more than one capacitor - G09G 2300/0861: with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes - G09G 2310/0251: Precharge or discharge of pixel before applying new pixel voltage - G09G 2310/0262: The addressing of the pixel, in a display other than an active matrix LCD, involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependent on signals of two data electrodes - G09G 2320/0233: Improving the luminance or brightness uniformity across the screen - G09G 2320/0285: using tables for spatial correction of display data - G09G 2320/043: Preventing or counteracting the effects of ageing - G09G 2330/021: Power management, e.g. power saving - G09G 2360/16: Calculation or use of calculated indices related to luminance levels in display data - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) ## Abstract A display apparatus has an image display unit having a plurality of arrayed pixel circuits, and an image signal compensation circuit compensating an image signal and outputs the compensated signal to the image display unit. Each of the pixel circuits has a compensating capacitor which compensates the threshold voltage of the driving transistor. The image signal compensation circuit has a compensation memory storing a compensation data for compensating the current variation of the driving transistors, a first comparison circuit which compares the image signal and first threshold value, and an arithmetic circuit compensating the image signal. When the image signal has a luminance larger than the threshold value, the compensation is performed. ## Claims ### Claim 1 A display apparatus comprising an image display unit having a plurality of arrayed pixel circuits, each of the pixel circuits having a current light emitting device and a driving transistor supplying current to the current light emitting device; and an image signal compensation circuit compensating an image signal and outputs the compensated signal to the image display unit; wherein each of the pixel circuits having a compensating capacitor which compensates a threshold voltage of a corresponding driving transistor; and the image signal compensation circuit having a compensation memory storing compensation data for compensating current dispersion between the driving transistors, a comparison circuit which compares the image signal with a threshold value of luminance, and an arithmetic circuit which outputs the compensated image signal being compensated based on the compensation data, and the image signal compensation circuit outputs the compensated image signal when the image signal has a luminance larger than the threshold value, and outputs the image signal when the image signal has a luminance smaller than the threshold value. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the image signal compensation circuit comprises a compensation memory storing the compensation data for compensating the variation of current in the driving transistor; a first comparison circuit comparing the image signal and a first threshold of luminance; a lighting ratio calculation circuit calculating a lighting ratio of the plurality of arrayed pixel circuits for every frame of the image signal; a second comparison circuit comparing the lighting ratio calculated by the lighting ratio calculation circuit and the second threshold which is different from the first threshold, and an arithmetic circuit which performs the compensation, wherein the image signal compensation circuit compensates the image signal when the image signal is larger than the first threshold and the lighting ratio is larger than the second threshold. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein each of the pixel circuits further comprises a first capacitor having a first terminal connected to a gate of the driving transistor; a second capacitor connected between a second terminal of the first capacitor and a source of the driving transistor; a first switch applying a reference voltage to a node to which the first and the second capacitors are connected; a second switch supplying an image signal voltage to the gate of the driving transistor; a third switch supplying an initialization voltage to drain of the driving transistor, and a fourth switch supplying current to the drain of the drive transistor for emitting light from the current light emitting device, wherein the second capacitor is the compensating capacitor.