# US 7,466,296 B2 · Apparatus and method for gamma correction in a liquid crystal display > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,466,296 B2 - Document ID: US7466296B2 - Status: Granted - Kind: B2 - Application number: 10/858,971 - Filed: 2004-06-02 - Published: 2004-11-04 - Granted: 2008-12-16 - Earliest claimed: 2001-12-31 - Assignees: Himax Technologies Limited - Inventors: Lin-Kai Bu - Web page: https://patentgrep.com/patent/US7466296B2 ## CPC - G09G 3/3611: {Control of matrices with row and column drivers} - G09G 3/3685: {Details of drivers for data electrodes} - G09G 3/3696: {Generation of voltages supplied to electrode drivers} - G09G 2310/027: Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters - 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: 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 gamma correction apparatus for a liquid crystal display comprises a reference voltage generating circuit and a gamma correction circuit. The reference voltage generating circuit outputs a plurality of reference voltages according to the pixel data. The gamma correction circuit gamma-corrects the pixel data according to the reference voltages. The feature of the invention resides in that the reference voltage generating circuit outputs the corresponding reference voltages to gamma-correct the pixel data according to the positions of the pixels corresponding to the pixel data in the LCD monitor and the display colors of the pixels. ## Claims ### Claim 1 A method for generating a driving voltage, comprising steps of: generating a plurality of digital reference signals according to a position of a pixel to which the driving voltage is applied; generating a plurality of analog reference voltages by performing digital-to-analog conversion according to the digital reference signals respectively; generating the driving voltage according to a digital pixel signal corresponding to the pixel and the analog reference voltages; and applying two of the analog reference voltages to a resistor string to generate a plurality of additional reference voltages. ### Claim 2 (depends on 1) The method of claim 1 further comprising a step of storing the digital reference signals. ### Claim 3 (depends on 1) The method of claim 1 further comprising a step of generating the digital reference signals according to a color of a pixel to which the driving voltage is applied. ### Claim 4 (depends on 1) The method of claim 1 further comprising a step of generating the digital reference signals according to a block to which a pixel, to which the driving voltage is applied, belong in a display. ### Claim 5 (depends on 1) The method of claim 1, wherein the driving voltage is generated further according to the additional reference voltages. ### Claim 6 (depends on 1) The method of claim 1, further comprising a step of applying the driving voltage to a pixel in a display. ### Claim 7 (depends on 1) The method of claim 1, wherein the analog reference voltages are generated further according to a color of a pixel to which the driving voltage is applied in the step of generating the analog reference voltages. ### Claim 8 (depends on 1) The method of claim 1, wherein the analog reference voltages are generated further according to a position of a pixel to which the driving voltage is applied in the step of generating the analog reference voltages. ### Claim 9 (depends on 1) The method of claim 1, wherein the analog reference voltages are generated further according to a block to which a pixel, to which the driving voltage is applied, belong in a display in the step of generating the analog reference voltages. ### Claim 10 A method of driving a liquid crystal display (LCD) having a plurality of pixels arranged in a matrix, comprising the steps of: generating a plurality of analog reference voltages according to a position of the pixel in the LCD; applying two of the analog reference voltages to a resistor string to generate a plurality of additional reference voltages; receiving a digital pixel signal corresponding to the pixel; and generating a driving voltage according to the digital pixel signal and the analog reference voltages and the additional reference voltages, wherein the driving voltage is applied to the pixel. ### Claim 11 (depends on 10) The method of claim 10 further comprising the steps of: generating a plurality of digital reference signals according to the position of the pixel in the LCD; and converting the digital reference signals to the analog reference voltages. ### Claim 12 (depends on 11) The method of claim 11 further comprising the steps of receiving and storing the digital reference signals. ### Claim 13 (depends on 10) The method of claim 10 wherein the step of generating the analog reference voltages is performed by a plurality of digital-to-analog converters. ### Claim 14 A method of driving a liquid crystal display (LCD) having a plurality of pixels arranged in a matrix, comprising the steps of: generating a plurality of digital reference signals according to a position of the pixel in the LCD and converting the digital reference signals to a plurality of analog reference voltages; generating further the plurality of analog reference voltages according to a color of the pixel in the LCD; applying two of the analog reference voltages to a resistor string to generate a plurality of additional reference voltages; receiving a digital pixel signal corresponding to the pixel; and generating a driving voltage according to the digital pixel signal and the analog reference voltages and the additional reference voltages, wherein the driving voltage is applied to the pixel. ### Claim 15 (depends on 14) The method of claim 14 further comprising the steps of receiving and storing the digital reference signals. ### Claim 16 (depends on 14) The method of claim 14 wherein the step of generating the analog reference voltages is performed by a plurality of digital-to-analog converters.