# US 10,504,428 B2 · Color variance gamma correction > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,504,428 B2 - Document ID: US10504428B2 - Status: Granted - Kind: B2 - Application number: 15/786,210 - Filed: 2017-10-17 - Published: 2019-04-18 - Granted: 2019-12-10 - Earliest claimed: 2017-10-17 - Assignees: Microsoft Technology Licensing, LLC - Applicants: Microsoft Technology Licensing, LLC - Inventors: Minhyuk Choi; Samu Matias Kallio; Ying Zheng - Web page: https://patentgrep.com/patent/US10504428B2 ## CPC - G09G 3/3233: with pixel circuitry controlling the current through the light-emitting element - G09G 3/2003: {Display of colours (specific for liquid crystal displays G09G3/3607)} - G09G 3/2074: {using sub-pixels} - G09G 3/3225: using an active matrix - H04N 9/73: Colour balance circuits, e.g. white balance circuits or colour temperature control (camera processing pipelines for colour balance H04N23/88) - G09G 2320/0223: Compensation for problems related to R-C delay and attenuation in electrodes of matrix panels, e.g. in gate electrodes or on-substrate video signal electrodes - G09G 2320/0242: Compensation of deficiencies in the appearance of colours - G09G 2320/0271: Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping - G09G 2320/0276: for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction - G09G 2320/0666: for control of colour parameters, e.g. colour temperature - G09G 2320/0673: for control of gamma adjustment, e.g. selecting another gamma curve - 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) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract While organic light-emitting diode (OLED) display devices are often calibrated upon commissioning to provide similar output colors in response to input signals, they are not calibrated based on varying display content. Significant variation in output color as a function of varying output display content is increasingly unacceptable to users. In an OLED display, an emissive electroluminescent layer selectively emits light in discrete areas in response to an electric current. Higher overall applied electrical currents correspond to higher overall output luminesces, however, as current is increased, attendant voltage generally drops. Variation in attendant voltage causes variation in output color. The presently disclosed display drivers that detect an on-pixel ratio of an input display signal, select a gamma correction factor, apply the selected gamma correction factor, and output a color-corrected display signal to the OLED display address variations in output color as a function of varying output display content. ## Claims ### Claim 1 A computing device comprising: an organic light-emitting diode (OLED) display; and a display driver to detect an on-pixel ratio (OPR) of an input display signal, select a gamma color correction factor based on the detected OPR to achieve a desired reference color, apply the selected gamma color correction factor to the input display signal, and output a color-corrected display signal to the OLED display. ### Claim 2 (depends on 1) The computing device of claim 1, wherein the display driver includes: a gamma correction selector to select the gamma color correction factor based on the detected OPR; and a gamma color corrector to apply the selected gamma color correction factor to the input display signal. ### Claim 3 (depends on 1) The computing device of claim 1, wherein the desired reference color is one or both of white point and gray color of the color-corrected display signal. ### Claim 4 (depends on 1) The computing device of claim 1, wherein the gamma color correction factor is applied to a portion of the input display signal corresponding to a discrete area of the OLED display. ### Claim 5 (depends on 1) The computing device of claim 1, further comprising: a display frame buffer to store the input display signal. ### Claim 6 (depends on 1) The computing device of claim 1, further comprising: a storage device to store the gamma color correction factor. ### Claim 7 (depends on 6) The computing device of claim 6, wherein the gamma color correction factor is selected from one or more look-up tables (LUTs) within the storage device. ### Claim 8 (depends on 6) The computing device of claim 6, wherein the gamma color correction factor is calculated in real time using one or more gamma color correction formulae stored within the storage device. ### Claim 9 (depends on 6) The computing device of claim 6, wherein the storage device includes one or both of volatile memory and a non-volatile storage media. ### Claim 10 A method of correcting output color on an organic light-emitting diode (OLED) display comprising: receiving an input display signal; detecting an on-pixel ratio (OPR) of the input display signal; selecting a gamma color correction factor corresponding to the detected OPR to achieve a desired reference color; applying the selected gamma color correction factor to the input display signal; and outputting a color-corrected display signal to the OLED display. ### Claim 11 (depends on 10) The method of claim 10, further comprising: assigning each of two or more gamma color correction factors to a distinct OPR range for the OLED display, wherein the gamma color correction factor is selected from the assigned two or more gamma color correction factors. ### Claim 12 (depends on 10) The method of claim 10, wherein the desired reference color is one or both of white point and gray color of the color-corrected display signal. ### Claim 13 (depends on 10) The method of claim 10, wherein the gamma color correction factor is applied to a portion of the input display signal corresponding to a discrete area of the OLED display. ### Claim 14 (depends on 10) The method of claim 10, wherein the gamma color correction factor is selected from one or more look-up tables (LUTs) within a storage device. ### Claim 15 (depends on 10) The method of claim 10, wherein the gamma color correction factor is calculated in real time using one or more gamma color correction formulae stored within a storage device. ### Claim 16 A tangible computer-readable medium containing processor-executable instructions that, when executed by a processor, cause the processor to: receive an input display signal; detect an on-pixel ratio (OPR) of the input display signal; select a gamma color correction factor corresponding to the detected OPR to achieve a desired reference color; apply the selected gamma color correction factor to the input display signal; and output a color-corrected display signal to an organic light-emitting diode (OLED) display. ### Claim 17 (depends on 16) The tangible computer-readable medium of claim 16, wherein the processor-executable instructions further cause the processor to: assign each of two or more gamma color correction factors to a distinct OPR range for the OLED display, wherein the gamma color correction factor is selected from the assigned two or more gamma color correction factors. ### Claim 18 (depends on 16) The tangible computer-readable medium of claim 16, wherein the gamma color correction factor is applied to a portion of the input display signal corresponding to a discrete area of the OLED display. ### Claim 19 (depends on 16) The tangible computer-readable medium of claim 16, wherein the gamma color correction factor is selected from one or more LUTs within a storage device. ### Claim 20 (depends on 16) The tangible computer-readable medium of claim 16, wherein the gamma color correction factor is calculated in real time using one or more gamma color correction formulae stored within a storage device.