# US 8,570,349 B2 · Method for dividing display area for local dimming, liquid crystal display device using the same, and method for driving the liquid crystal display device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,570,349 B2 - Document ID: US8570349B2 - Status: Granted - Kind: B2 - Application number: 12/827,537 - Filed: 2010-06-30 - Published: 2011-06-09 - Granted: 2013-10-29 - Earliest claimed: 2009-12-07 - Assignees: LG Display Co., Ltd. - Applicants: Kyung-Joon Kwon; Si-Hoon Lee; Jung-Hwan Lee - Inventors: Kyung-Joon Kwon; Si-Hoon Lee; Jung-Hwan Lee - Web page: https://patentgrep.com/patent/US8570349B2 ## CPC - G09G 3/3426: {the different display panel areas being distributed in two dimensions, e.g. matrix} - G09G 2320/02: Improving the quality of display appearance - G09G 2320/0646: Modulation of illumination source brightness and image signal correlated to each other - 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 method for dividing a display area for local dimming of LCD is disclosed. The method includes determining an initial number of pixels per data analysis area and a total number of residual pixels, calculating a first residual pixel sum of a current data analysis area using the total number of residual pixels and a second residual pixel sum of a previous data analysis area, determining whether to assign a residual pixel to the current data analysis area using the first residual pixel sum and the total number of data analysis areas, calculating a second residual sum of the current data analysis area whether to assign a residual pixel, and repeating the calculation above until the data analysis area index is a last data analysis area index. ## Claims ### Claim 1 A method for dividing a display area for local dimming, comprising: determining an initial number of pixels per data analysis area and a total number of residual pixels using a resolution of the display area and a total number of data analysis areas equal to a total number of local dimming areas of a backlight unit; calculating a first residual pixel sum of a current data analysis area by adding the total number of residual pixels to a second residual pixel sum of a previous data analysis area, each time a data analysis area index increases; comparing the first residual pixel sum of the current data analysis area with the total number of data analysis areas and determining whether to assign a residual pixel to the current data analysis area according to a result of the comparison; calculating a second residual sum of the current data analysis area by subtracting the total number of data analysis areas from the first residual pixel sum of the current data analysis area and outputting the second residual sum of the current data analysis area as the second residual sum of the previous data analysis area for a next data analysis area, if a residual pixel is assigned to the current data analysis area; setting the first residual sum of the current data analysis area as the second residual sum of the current data analysis area and outputting the second residual sum of the current data analysis area as the second residual sum of the previous data analysis area for the next data analysis area, if a residual pixel is not assigned to the current data analysis area; and repeating the calculation of a first residual pixel sum of a current data analysis area, the determination as to whether to assign a residual pixel to the current data analysis area, and the outputting of a second residual pixel sum of the current data analysis area, until the data analysis area index is a last data analysis area index, wherein the determination of an initial number of pixels per data analysis area and a total number of residual pixels comprises: determining an integer obtained by diving the resolution by the total number of data analysis areas as the initial number of pixels per data analysis area; and determining the total number of residual pixels by calculating “the resolution-(the initial number of pixels per data analysis area)×(the total number of data analysis areas)”. ### Claim 2 (depends on 1) The method according to claim 1, wherein if the backlight unit is driven in parallel through a plurality of ports, the determination of the total number of residual pixels comprises determining the total number of residual pixels by calculating “(the resolution/a number of the ports)-(the initial number of pixels per data analysis area)×(the total number of data analysis areas)”. ### Claim 3 (depends on 2) The method according to claim 2, wherein the calculation of a first residual pixel sum of a current data analysis area comprises calculating the first residual pixel sum of the current data analysis area by adding the total number of residual pixels to the second residual pixel sum of the previous data analysis area. ### Claim 4 (depends on 3) The method according to claim 3, wherein the determination as to whether to assign a residual pixel to the current data analysis area comprises: distributing one residual pixel to the current data analysis area, if the first residual pixel sum of the current data analysis area is larger than the total number of data analysis areas; and determining a final number of pixels in the current data analysis area by adding one to the initial number of pixels per data analysis areas. ### Claim 5 (depends on 4) The method according to claim 4, wherein the determination as to whether to assign a residual pixel to the current data analysis area further comprises: determining the final number of pixels in the current data analysis as the initial number of pixels per data analysis areas without assigning a residual pixel to the current data analysis area, if the first residual pixel sum of the current data analysis area is equal to or smaller than the total number of data analysis areas. ### Claim 6 (depends on 5) The method according to claim 5, wherein the determination of an initial number of pixels per data analysis area and a total number of residual pixels, the calculation of a first residual pixel sum of a current data analysis area, the determination as to whether to assign a residual pixel to the current data analysis area, the outputting of a second residual pixel sum of the current data analysis area, and the repetition are performed for each of horizontal and vertical resolutions of the resolution of the display area. ### Claim 7 (depends on 6) The method according to claim 6, wherein one residual pixel is assigned to each of as many data analysis areas as the total number of residual pixels, among the data analysis areas. ### Claim 8 A method for driving a Liquid Crystal Display (LCD) device, comprising analyzing data on a data analysis area basis using information about the data analysis areas set by a method for dividing a display area for local dimming modulating the data on a data analysis area basis according to a result of the analysis, and determining a local dimming value for each of the local dimming blocks according to the result of the analysis, wherein the method for dividing a display area for local dimming, comprises: determining an initial number of pixels per data analysis area and a total number of residual pixels using a resolution of the display area and a total number of data analysis areas equal to a total number of local dimming areas of a backlight unit; calculating a first residual pixel sum of a current data analysis area by adding the total number of residual pixels to a second residual pixel sum of a previous data analysis area, each time a data analysis area index increases; comparing the first residual pixel sum of the current data analysis area with the total number of data analysis areas and determining whether to assign a residual pixel to the current data analysis area according to a result of the comparison; calculating a second residual sum of the current data analysis area by subtracting the total number of data analysis areas from the first residual pixel sum of the current data analysis area and outputting the second residual sum of the current data analysis area as the second residual sum of the previous data analysis area for a next data analysis area, if a residual pixel is assigned to the current data analysis area; setting the first residual sum of the current data analysis area as the second residual sum of the current data analysis area and outputting the second residual sum of the current data analysis area as the second residual sum of the previous data analysis area for the next data analysis area, if a residual pixel is not assigned to the current data analysis area; and repeating the calculation of a first residual pixel sum of a current data analysis area, the determination as to whether to assign a residual pixel to the current data analysis area, and the outputting of a second residual pixel sum of the current data analysis area, until the data analysis area index is a last data analysis area index, wherein the determination of an initial number of pixels per data analysis area and a total number of residual pixels comprises: determining an integer obtained by diving the resolution by the total number of data analysis areas as the initial number of pixels per data analysis area; and determining the total number of residual pixels by calculating “the resolution-(the initial number of pixels per data analysis area)×(the total number of data analysis areas)”. ### Claim 9 (depends on 8) The method according to claim 8, wherein if the backlight unit is driven in parallel through a plurality of ports, the determination of the total number of residual pixels comprises determining the total number of residual pixels by calculating “(the resolution/a number of the ports)−(the initial number of pixels per data analysis area)×(the total number of data analysis areas)”. ### Claim 10 (depends on 9) The method according to claim 9, wherein the calculation of a first residual pixel sum of a current data analysis area comprises calculating the first residual pixel sum of the current data analysis area by adding the total number of residual pixels to the second residual pixel sum of the previous data analysis area. ### Claim 11 (depends on 10) The method according to claim 10, wherein the determination as to whether to assign a residual pixel to the current data analysis area comprises: distributing one residual pixel to the current data analysis area, if the first residual pixel sum of the current data analysis area is larger than the total number of data analysis areas; and determining a final number of pixels in the current data analysis area by adding one to the initial number of pixels per data analysis areas. ### Claim 12 (depends on 11) The method according to claim 11, wherein the determination as to whether to assign a residual pixel to the current data analysis area further comprises: determining the final number of pixels in the current data analysis as the initial number of pixels per data analysis areas without assigning a residual pixel to the current data analysis area, if the first residual pixel sum of the current data analysis area is equal to or smaller than the total number of data analysis areas. ### Claim 13 (depends on 12) The method according to claim 12, wherein the determination of an initial number of pixels per data analysis area and a total number of residual pixels, the calculation of a first residual pixel sum of a current data analysis area, the determination as to whether to assign a residual pixel to the current data analysis area, the outputting of a second residual pixel sum of the current data analysis area, and the repetition are performed for each of horizontal and vertical resolutions of the resolution of the display area. ### Claim 14 (depends on 13) The method according to claim 13, wherein one residual pixel is assigned to each of as many data analysis areas as the total number of residual pixels, among the data analysis areas. ### Claim 15 An Liquid Crystal Display (LCD) device, comprising: a backlight unit for projecting light; a liquid crystal panel for displaying an image using the light received from the backlight unit; a local dimming driver for analyzing data on a data analysis area basis using information about the data analysis areas set by a method for dividing a display area for local dimming, modulating the data on a data analysis area basis according to a result of the analysis, and determining a local dimming value for each of the local dimming blocks according to the result of the analysis; a panel driver for outputting the data received from the local dimming driver to the liquid crystal panel; and a backlight driver for controlling luminance of the backlight unit on a local dimming block basis according to the local dimming value of each local dimming block received from the local dimming driver, wherein the method for dividing a display area for local dimming, comprises: determining an initial number of pixels per data analysis area and a total number of residual pixels using a resolution of the display area and a total number of data analysis areas equal to a total number of local dimming areas of a backlight unit; calculating a first residual pixel sum of a current data analysis area by adding the total number of residual pixels to a second residual pixel sum of a previous data analysis area, each time a data analysis area index increases; comparing the first residual pixel sum of the current data analysis area with the total number of data analysis areas and determining whether to assign a residual pixel to the current data analysis area according to a result of the comparison; calculating a second residual sum of the current data analysis area by subtracting the total number of data analysis areas from the first residual pixel sum of the current data analysis area and outputting the second residual sum of the current data analysis area as the second residual sum of the previous data analysis area for a next data analysis area, if a residual pixel is assigned to the current data analysis area; setting the first residual sum of the current data analysis area as the second residual sum of the current data analysis area and outputting the second residual sum of the current data analysis area as the second residual sum of the previous data analysis area for the next data analysis area, if a residual pixel is not assigned to the current data analysis area; and repeating the calculation of a first residual pixel sum of a current data analysis area, the determination as to whether to assign a residual pixel to the current data analysis area, and the outputting of a second residual pixel sum of the current data analysis area, until the data analysis area index is a last data analysis area index wherein the determination of an initial number of pixels per data analysis area and a total number of residual pixels comprises: determining an integer obtained by diving the resolution by the total number of data analysis areas as the initial number of pixels per data analysis area; and determining the total number of residual pixels by calculating “the resolution-(the initial number of pixels per data analysis area)×(the total number of data analysis areas)”. ### Claim 16 (depends on 15) The device according to claim 15, wherein if the backlight unit is driven in parallel through a plurality of ports, the determination of the total number of residual pixels comprises determining the total number of residual pixels by calculating “(the resolution/a number of the ports)−(the initial number of pixels per data analysis area)×(the total number of data analysis areas)”. ### Claim 17 (depends on 16) The device according to claim 16, wherein the calculation of a first residual pixel sum of a current data analysis area comprises calculating the first residual pixel sum of the current data analysis area by adding the total number of residual pixels to the second residual pixel sum of the previous data analysis area. ### Claim 18 (depends on 17) The device according to claim 17, wherein the determination as to whether to assign a residual pixel to the current data analysis area comprises: distributing one residual pixel to the current data analysis area, if the first residual pixel sum of the current data analysis area is larger than the total number of data analysis areas; and determining a final number of pixels in the current data analysis area by adding one to the initial number of pixels per data analysis areas. ### Claim 19 (depends on 18) The device according to claim 18, wherein the determination as to whether to assign a residual pixel to the current data analysis area further comprises: determining the final number of pixels in the current data analysis as the initial number of pixels per data analysis areas without assigning a residual pixel to the current data analysis area, if the first residual pixel sum of the current data analysis area is equal to or smaller than the total number of data analysis areas. ### Claim 20 (depends on 19) The device according to claim 19, wherein the determination of an initial number of pixels per data analysis area and a total number of residual pixels, the calculation of a first residual pixel sum of a current data analysis area, the determination as to whether to assign a residual pixel to the current data analysis area, the outputting of a second residual pixel sum of the current data analysis area, and the repetition are performed for each of horizontal and vertical resolutions of the resolution of the display area. ### Claim 21 (depends on 20) The device according to claim 20, wherein one residual pixel is assigned to each of as many data analysis areas as the total number of residual pixels, among the data analysis areas.