# US 2019/0318679 A1 · Tone correction data preparation device, tone correction device, electronic apparatus, and tone correction data preparation method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0318679 A1 - Document ID: US20190318679A1 - Status: Published application - Kind: A1 - Application number: 16/381,855 - Filed: 2019-04-11 - Published: 2019-10-17 - Earliest claimed: 2018-04-13 - Assignees: Sharp Kabushiki Kaisha - Applicants: Sharp Kabushiki Kaisha - Inventors: TAKUYA MATSUISHI - Web page: https://patentgrep.com/patent/US20190318679A1 ## CPC - G09G 3/2003: {Display of colours (specific for liquid crystal displays G09G3/3607)} - G09G 3/2007: {Display of intermediate tones} - G09G 3/3607: {for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels (display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127)} - G09G 3/36: using liquid crystals - G09G 2320/0242: Compensation of deficiencies in the appearance of colours - 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 2320/0693: Calibration of display systems - G09G 2340/06: Colour space transformation - G09G 2360/145: the light originating from the display screen - 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 driver calculates a white gamma curve based on a deviation of a tone (including a maximum tone) of white displayed on a liquid crystal display panel (LCD panel) with respect to a target tone value and on a measured gamma value at arbitrary tones excluding a maximum tone in a white gamma characteristic of the LCD panel. The driver calculates three primary gamma curves by applying, to the white gamma curve, a relation obtained by comparing a gamma curve of white of a reference display panel with gamma curves of respective red, green, and blue. The driver corrects a white balance of display data based on the three primary gamma curves and expected output values of respective three primary colors calculated based on highest tone values of three primary colors of the reference display panel and of white of the LCD panel. ## Claims ### Claim 1 A tone correction data preparation device comprising: a white gamma curve calculating section which calculates a white gamma curve based on a deviation of a tone of white displayed on a display panel with respect to a target tone value and on a measured gamma value, the tone including a maximum tone and being measured at one or more measurement points, the measured gamma value being measured at one or more measurement points which are at respective one or more arbitrary tones excluding a maximum tone in a white gamma characteristic of the display panel; a three primary gamma curve calculating section which calculates three primary gamma curves of respective red, green, and blue by applying, to the white gamma curve, a relation obtained by comparing a gamma curve of white of a reference display panel having an ideal gamma characteristic with gamma curves of respective red, green, and blue of the reference display panel; and a conversion value calculating section which calculates, based on expected output values of respective three primary colors and the three primary gamma curves, a conversion value for converting inputted display data into corrected display data in which a white balance has been corrected, the expected output values being calculated by the conversion value calculating section based on highest tone values of respective three primary colors of the reference display panel and on a highest tone value of white of the display panel. ### Claim 2 (depends on 1) The tone correction data preparation device as set forth in claim 1, wherein: the white gamma curve calculating section calculates the white gamma curve with use of the measured gamma value on a higher tone side. ### Claim 3 (depends on 1) A tone correction device comprising: a tone correction data preparation device recited in claim 1; a conversion process section which converts the inputted display data into the corrected display data based on the conversion value; and a gamma correction section which corrects the corrected display data with a predetermined gamma characteristic. ### Claim 4 (depends on 3) The tone correction device as set forth in claim 3, wherein: said tone correction device is provided in a display driving circuit which supplies, to the display panel, output display data which has been subjected to gamma correction by the gamma correction section. ### Claim 5 (depends on 3) The tone correction device as set forth in claim 3, wherein: said tone correction device controls a display driving circuit which supplies, to the display panel, output display data which has been subjected to gamma correction by the gamma correction section; and said tone correction device is provided in a control device which outputs the inputted display data. ### Claim 6 (depends on 3) An electronic apparatus comprising: a tone correction device recited in claim 3; and the display panel. ### Claim 7 A method for preparing tone correction data, said method comprising the steps of: calculating a white gamma curve based on a deviation of a tone of white displayed on a display panel with respect to a target tone value and on a measured gamma value, the tone including a maximum tone and being measured at one or more measurement points, the measured gamma value being measured at one or more measurement points which are at respective one or more arbitrary tones excluding a maximum tone in a white gamma characteristic of the display panel; calculating three primary gamma curves of respective red, green, and blue based on a relation obtained by comparing gamma curves of respective red, green, and blue of a reference display panel having an ideal gamma characteristic with the white gamma curve; and calculating, based on expected output values of respective three primary colors and the three primary gamma curves, a conversion value for converting inputted display data into corrected display data in which a white balance has been corrected, the expected output values being calculated based on highest tone values of respective three primary colors of the reference display panel and on a highest tone value of white of the display panel.