# US 10,121,408 B2 · Method of eliminating OLED display panel Mura > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,121,408 B2 - Document ID: US10121408B2 - Status: Granted - Kind: B2 - Application number: 15/108,779 - Filed: 2016-04-27 - Published: 2018-04-12 - Granted: 2018-11-06 - Earliest claimed: 2016-03-31 - Assignees: Shenzhen China Star Optoelectronics Technology Co., Ltd. - Applicants: Shenzhen China Star Optoelectronics Technology Co., Ltd. - Inventors: Yufan Deng - Web page: https://patentgrep.com/patent/US10121408B2 ## CPC - G09G 3/3208: organic, e.g. using organic light-emitting diodes [OLED] - G09G 3/2074: {using sub-pixels} - G09G 2320/0233: Improving the luminance or brightness uniformity across the screen - G09G 2320/0276: for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction - G09G 2320/0295: by monitoring each display pixel - G09G 2320/0626: for control of overall brightness - G09G 2320/0673: for control of gamma adjustment, e.g. selecting another gamma curve - 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 The present invention provides a method of eliminating OLED display panel Mura. First, a corresponding calculation formula is selected by comparing the gamma value of the OLED display panel and the local gamma value at the present display gray scale, and the compensation gray scale which should be utilized is calculated, and then the OLED display panel is made to show the present compensation gray scale captured with the present calculation to determine whether the preset condition of ending the calculation of the compensation gray scale is achieved, and if the preset condition of ending the calculation of the compensation gray scale is not achieved, the iterative computation does not stop until the preset condition of ending the calculation of the compensation gray scale is achieved, which can rapidly and effectively eliminate the OLED display panel Mura to ensure the brightness uniformity of the OLED display panel. ## Claims ### Claim 1 A method of eliminating organic light emitting display (OLED) panel Mura, comprising steps of: step 1, providing an OLED panel and a brightness capturing device, and the OLED panel is made to show a 255 gray scale, and employing the brightness capturing device to capture actual brightnesses of respective sub pixels of the OLED panel at the 255 gray scale; step 2, making the OLED panel show a gray scale to be compensated; step 3, employing the brightness capturing device to capture actual brightnesses of respective sub pixels of the OLED panel at a present display gray scale; step 4, calculating a local gamma value at the present display gray scale, and a calculation formula is: Gamma ⁢ i = log ⁡ ( L i L 255 ) log ⁡ ( Gray i 255 ) wherein i is an integer larger than or equal to 0, and i+1 is a number of a present iterative computation, and Gammai, is the local gamma value at the present display gray scale, and Li is the actual brightness of the sub pixel at the present display gray scale, and L255 is the actual brightness of the sub pixel at the 255 gray scale, and the Grayi is the present display gray scale; step 5, capturing a gamma value of the OLED panel and preset target brightnesses of respective sub pixels, and selecting a corresponding calculation formula by comparing the gamma value of the OLED panel and the local gamma value at the present display gray scale to obtain a compensation gray scale should be utilized for achieving the preset target brightness of the sub pixel, and a specific calculation formula and an application condition are: if the local gamma value at the present display gray scale is larger than twice of the gamma value of the OLED panel, then the compensation gray scale should be utilized is calculated according to the following formula; Gray i + 1 = ( L goal L 255 ) 1 Gamma i × 255 ; wherein Lgoal is a target brightness of the sub pixel, and Grayi+1 is the compensation gray scale; if the local gamma value at the present display gray scale is smaller than twice of the gamma value of the OLED panel, then the compensation gray scale should be utilized is calculated according to the following formula; Gray i + 1 = ( L goal L i ) 1 γ × Gray i ; wherein γ is the gamma value of the OLED panel; step 6, making OLED panel to show the compensation gray scale obtained by a present calculation to determine whether a preset condition of ending the calculation of the compensation gray scale is achieved; if the condition of ending the calculation of the compensation gray scale is not achieved, then returning back to the step 3; if the condition of ending the calculation of the compensation gray scale is achieved, then ending the method. ### Claim 2 (depends on 1) The method of eliminating OLED panel Mura according to claim 1, wherein the brightness capturing device is a brightness meter. ### Claim 3 (depends on 1) The method of eliminating OLED panel Mura according to claim 1, wherein the brightness capturing device is a charge coupled device (CCD). ### Claim 4 (depends on 3) The method of eliminating OLED panel Mura according to claim 3, wherein in the step 3, a picture of a display image of the OLED panel at the present display gray scale is captured with the CCD to obtain actual brightnesses of the respective sub pixels of the OLED panel at the present gray scale. ### Claim 5 (depends on 1) The method of eliminating OLED panel Mura according to claim 1, wherein in the step 6, the condition of ending the calculation of the compensation gray scale is: a difference value of the actual brightness and the target brightness of the sub pixel is smaller than a preset allowable deviation brightness. ### Claim 6 (depends on 1) The method of eliminating OLED panel Mura according to claim 1, wherein in the step 6, the condition of ending the calculation of the compensation gray scale is: the number of the present iterative computation reaches a preset number of a maximum iterative computation. ### Claim 7 (depends on 6) The method of eliminating OLED panel Mura according to claim 6, wherein the preset number of the maximum iterative computation is three. ### Claim 8 (depends on 1) The method of eliminating OLED panel Mura according to claim 1, wherein in the step 6, the condition of ending the calculation of the compensation gray scale is: a difference value of the actual brightness and the target brightness of the sub pixel is smaller than a preset error brightness or the number of the present iterative computation reaches a preset number of a maximum iterative computation. ### Claim 9 (depends on 1) The method of eliminating OLED panel Mura according to claim 1, wherein in the step 5, the preset target brightnesses of the respective sub pixels are captured with a corresponding gamma curve of the gamma value of the OLED panel. ### Claim 10 A method of eliminating organic light emitting display (OLED) panel Mura, comprising steps of: step 1, providing an OLED panel and a brightness capturing device, and the OLED panel is made to show a 255 gray scale, and employing the brightness capturing device to capture actual brightnesses of respective sub pixels of the OLED panel at the 255 gray scale; step 2, making the OLED panel show a gray scale to be compensated; step 3, employing the brightness capturing device to capture actual brightnesses of respective sub pixels of the OLED panel at a present display gray scale; step 4, calculating a local gamma value at the present display gray scale, and a calculation formula is: Gamma ⁢ i = log ⁡ ( L i L 255 ) log ⁡ ( Gray i 255 ) wherein i is an integer larger than or equal to 0, and i+1 is a number of a present iterative computation, and Gammai is the local gamma value at the present display gray scale, and Li is the actual brightness of the sub pixel at the present display gray scale, and L255 is the actual brightness of the sub pixel at the 255 gray scale, and the Grayi is the present display gray scale; step 5, capturing a gamma value of the OLED panel and preset target brightnesses of respective sub pixels, and selecting a corresponding calculation formula by comparing the gamma value of the OLED panel and the local gamma value at the present display gray scale to obtain a compensation gray scale should be utilized for achieving the preset target brightness of the sub pixel, and a specific calculation formula and an application condition are: if the local gamma value at the present display gray scale is larger than twice of the gamma value of the OLED panel, then the compensation gray scale should be utilized is calculated according to the following formula; Gray i + 1 = ( L goal L 255 ) 1 Gamma i × 255 ; wherein Lgoal is a target brightness of the sub pixel, and Grayi+1 is the compensation gray scale; if the local gamma value at the present display gray scale is smaller than twice of the gamma value of the OLED panel, then the compensation gray scale should be utilized is calculated according to the following formula; Gray i + 1 = ( L goal L i ) 1 γ × Gray i ; wherein γ is the gamma value of the OLED panel; step 6, making OLED panel to show the compensation gray scale obtained by a present calculation to determine whether a preset condition of ending the calculation of the compensation gray scale is achieved; if the condition of ending the calculation of the compensation gray scale is not achieved, then returning back to the step 3; if the condition of ending the calculation of the compensation gray scale is achieved, then ending the method; wherein the brightness capturing device is a charge coupled device (CCD); wherein in the step 5, the preset target brightnesses of the respective sub pixels are captured with a corresponding gamma curve of the gamma value of the OLED panel. ### Claim 11 (depends on 10) The method of eliminating OLED panel Mura according to claim 10, wherein in the step 3, a picture of a display image of the OLED panel at the present display gray scale is captured with the CCD to obtain actual brightnesses of the respective sub pixels of the OLED panel at the present gray scale. ### Claim 12 (depends on 10) The method of eliminating OLED panel Mura according to claim 10, wherein in the step 6, the condition of ending the calculation of the compensation gray scale is: a difference value of the actual brightness and the target brightness of the sub pixel is smaller than a preset allowable deviation brightness. ### Claim 13 (depends on 10) The method of eliminating OLED panel Mura according to claim 10, wherein in the step 6, the condition of ending the calculation of the compensation gray scale is: the number of the present iterative computation reaches a preset number of a maximum iterative computation. ### Claim 14 (depends on 13) The method of eliminating OLED panel Mura according to claim 13, wherein the preset number of the maximum iterative computation is three. ### Claim 15 (depends on 10) The method of eliminating OLED panel Mura according to claim 10, wherein in the step 6, the condition of ending the calculation of the compensation gray scale is: a difference value of the actual brightness and the target brightness of the sub pixel is smaller than a preset error brightness or the number of the present iterative computation reaches a preset number of a maximum iterative computation.