# US 8,570,263 B2 · Electronic equipment including LED backlight > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,570,263 B2 - Document ID: US8570263B2 - Status: Granted - Kind: B2 - Application number: 12/776,612 - Filed: 2010-05-10 - Published: 2010-09-02 - Granted: 2013-10-29 - Earliest claimed: 1999-03-18 - Assignees: Semiconductor Energy Laboratory Co., Ltd. - Applicants: Shunpei Yamazaki; Jun Koyama - Inventors: Shunpei Yamazaki; Jun Koyama - Web page: https://patentgrep.com/patent/US8570263B2 ## CPC - G09G 3/30: using electroluminescent panels - G09G 3/3648: {using an active matrix (G09G3/367 - G09G3/3696 take precedence)} - G09G 3/2011: {by amplitude modulation} - G09G 3/2018: {by time modulation using two or more time intervals} - G09G 3/3688: {suitable for active matrices only} - G09G 2310/027: Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters - 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 An object of the present invention is to provide a display device which enables multi-gray scale display without complicating the structure of D/A converter circuit. The measure taken to achieve the object is to use n bit of information among m bit digital video data inputted from external for voltage gray scale method, and (m−n) bit of information for time ratio gray scale. ## Claims ### Claim 1 An electronic equipment comprising: a display device including a plurality of pixels over a substrate; an LED backlight; a D/A converter circuit; and a circuit which converts m-bit digital video data into n-bit digital video data, wherein the m and the n are integers equal to or larger than 2 and satisfy m>n, wherein n-bit information out of the m-bit digital video data is used for a voltage gray scale method and (m−n)-bit information is used for a time ratio gray scale method, wherein each of a voltage level for the voltage gray scale method is designated as (VH−VL)/2n, where VH is the highest voltage level of voltages inputted to the D/A converter circuit, and VL is the lowest voltage level of voltages inputted to the D/A converter circuit, and wherein one frame period includes 2m-n subframe periods. ### Claim 2 (depends on 1) The electronic equipment according to claim 1, wherein the display device contains thresholdless antiferroelectric mixed liquid crystal indicating electric-optical characteristic of V-shape. ### Claim 3 (depends on 1) The electronic equipment according to claim 1, wherein the display device is configured to perform a field sequential operation. ### Claim 4 (depends on 1) The electronic equipment according to claim 1, wherein the electronic equipment is one selected from the group consisting of a telephone, a camera, a computer, an electronic book, an electronic game equipment, a projector, and a goggle type display. ### Claim 5 An electronic equipment comprising: a display device including a plurality of pixels over a substrate; an LED backlight; a D/A converter circuit; and a circuit which converts m-bit digital video data into n-bit digital video data, wherein the m and the n are integers equal to or larger than 2 and satisfy m>n, wherein n-bit information out of the m-bit digital video data is used for a voltage gray scale method and (m−n)-bit information is used for a time ratio gray scale method, and wherein each of a voltage level for the voltage gray scale method is designated as (VH−VL)/2n, where VH is the highest voltage level of voltages inputted to the D/A converter circuit, and VL is the lowest voltage level of voltages inputted to the D/A converter circuit. ### Claim 6 (depends on 5) The electronic equipment according to claim 5, wherein the display device contains thresholdless antiferroelectric mixed liquid crystal indicating electric-optical characteristic of V-shape. ### Claim 7 (depends on 5) The electronic equipment according to claim 5, wherein the display device is configured to perform a field sequential operation. ### Claim 8 (depends on 5) The electronic equipment according to claim 5, wherein the electronic equipment is one selected from the group consisting of a telephone, a camera, a computer, an electronic book, an electronic game equipment, a projector, and a goggle type display. ### Claim 9 An electronic equipment comprising: a display device including a plurality of pixels over a substrate; an LED backlight; and a D/A converter circuit; wherein n-bit information out of m-bit digital video data is used for a voltage gray scale method and (m−n)-bit information is used for a time ratio gray scale method, wherein the m and the n are integers equal to or larger than 2 and satisfy m>n, wherein each of a voltage level for the voltage gray scale method is designated as (VH−VL)/2n, where VH is the highest voltage level of voltages inputted to the D/A converter circuit, and VL is the lowest voltage level of voltages inputted to the D/A converter circuit, and wherein one frame period includes 2m-n subframe periods. ### Claim 10 (depends on 9) The electronic equipment according to claim 9, wherein the display device contains thresholdless antiferroelectric mixed liquid crystal indicating electric-optical characteristic of V-shape. ### Claim 11 (depends on 9) The electronic equipment according to claim 9, wherein the display device is configured to perform a field sequential operation. ### Claim 12 (depends on 9) The electronic equipment according to claim 9, wherein the electronic equipment is one selected from the group consisting of a telephone, a camera, a computer, an electronic book, an electronic game equipment, a projector, and a goggle type display.